Exosomes: Mediators of cellular communication in potentially malignant oral lesions and head and neck cancers

Monica Charlotte Solomon; Chetana Chandrashekar; Spoorti Kulkarni; Nisha Shetty; Aditi Pandey

doi:10.12688/f1000research.127368.2

. 2023 Oct 4;12:58. Originally published 2023 Jan 13. [Version 2] doi: 10.12688/f1000research.127368.2

Exosomes: Mediators of cellular communication in potentially malignant oral lesions and head and neck cancers

Monica Charlotte Solomon ^1,^a, Chetana Chandrashekar ¹, Spoorti Kulkarni ¹, Nisha Shetty ¹, Aditi Pandey ¹

PMCID: PMC10696492 PMID: 38059133

Version Changes

Revised. Amendments from Version 1

The revised version elaborates on the morphological and molecular characteristics of exosomes. The role of salivary exosomes in dysplastic lesions and oral cancer is described. The different methods by which exosomes can be employed for chemotherapeutic drug delivery is explained. The mechanism by which exosomes bring about drug resistance in tumor cells is explained. The challenges related to the clinical application of exosomes is described. Two figures have also been added.

Abstract

Exosomes are a unique type of extracellular vesicles that contain a plethora of biological cargo such as miRNA, mRNA, long non-coding RNA, DNA, proteins and lipids. Exosomes serve as very effective means of intercellular communication. Due the presence of a lipid bilayer membrane, exosomes are resistant to degradation and are highly stable. This makes them easily identifiable in blood and other bodily fluids such as saliva. The exosomes that are secreted from a parent cell directly release their contents into the cytoplasm of a recipient cell and influence their cellular activity and function. Exosomes can also transfer their content between cancer cells and normal cells and regulate the tumor microenvironment. Exosomes play a vital role in tumor growth, tumor invasion and metastasis. Exosomes provide a multitude of molecular and genetic information and have become valuable indicators of disease activity at the cellular level. This review explores the molecular characteristics of exosomes and the role that exosomes play in the tumorigenesis pathway of potentially malignant oral lesions and head and neck cancers The application of exosomes in the treatment of oral cancers is also envisioned.

Exosomes are very small and can easily pass through various biological barriers, making them very good delivery vectors for therapeutic drugs as well as to selectively induce DNA’s mRNA and miRNAs into targeted cancer cells.

Keywords: Exosomes, miRNA, intercellular communication, tumor microenvironment, invasion and metastasis

Introduction

Exosomes are a form of extracellular vesicles (EVs) that were first described by Pan and Johnstone in 1980. They were first identified as endocytic vesicles released by maturing reticulocytes. ¹ ^, ²

Exosomes are formed intracellularly, and the size of exosomes ranges from 30nm-150nm. The exosomes contain a plethora of biological entities such as proteins, lipids, DNA, microRNA, messenger RNA and long noncoding RNA enclosed in a lipid bilayer. ³ ^, ⁴

Exosomes originally form as intraluminal vesicles within the endosome and are released to the environment by fusion with the plasma membrane. ⁵ Exosomes are formed by the invagination of the endosomal plasma membrane during the transformation of an early endosome into a late endosome. The late endosomes, also known as microvesicular bodies, fuse with the cell membrane and release their contents into the extracellular environment and are now called exosomes ⁶ ( Figure 1). The formation of exosomes depends on two different pathways; the first an endosomal sorting complex required for transport (ESCRT)-dependent mechanism, and an ESCRT-independent mechanism. ⁷ Several factors influence the release of exosomes into the extracellular environment, such as oxidative stress and hypoxia. In addition, drugs such as sitafloxacin, pentatrezole and fenoterol activate the production of exosomes. ⁸

Exosomes are an unique mode of intercellular communication for transferring bioactive cargo to recipient cells. ⁹ As exosomes are released into the extracellular compartment, they are richly available in most of the body’s fluids including saliva. The lipid bilayer membrane that forms around the exosome capsule protects their cargo from degradation and RNAse damage, thus allowing exosomes to be highly stable in circulation. ¹⁰

Exosomes play a vital role in transferring molecular mediators and promote cell-to-cell communication both locally and to distant sites. ¹¹ When exosomes release the protein, signaling molecules, mRNA and miRNA into the cytoplasm of the target cells, this modifies the cell biology of that target cell. ¹²

The mRNA and the miRNA that are present in exosomes can be translated into proteins in the target cells that they enter, thereby transferring genetic information from one cell to another cell. ¹³

This review elucidates the molecular characteristic of exosomes and their implication in the biology of potentially malignant oral disorders and head and neck cancers.

Characteristic features of exosomes

Zlotogorski et al. ¹⁴ elucidated the molecular characteristics of exosomes through several molecular techniques such as transmission electron microscopy, nanoparticle tracking, atomic force microscopy, ELISA and Western blot. In his experimental analysis he compared the morphological features and molecular characteristic of exosomes in oral fluids of healthy individual and oral cancer patients. The details are as follows.

Transmission electron microscopy

Oral fluids collected from 36 Oral Cancer patients and from 25 Healthy individuals was centrifuged to remove the cell fragments and residual organelles and the supernatant was removed. The pellet that remained after the removal of the supernatant was washed and purified These pellets were dehydrated and fixed with epoxy resins and ultrathin sections were cut and the ultrastructural features were evaluated under a TEM. The ultrastructural features of the pellets that were obtained from the saliva of both healthy individuals and oral cancer patients showed nanoparticles that resembled exosomes. They appear as round-shaped vesicles surrounded by bilayered membranes.

Nanoparticle tracking analysis

The number of exosomes in saliva as determined by nanoparticle tracking analysis was 17.9±12.45E8 particles/ml in healthy individuals, while that in oral cancer patients was 36.0±7.5E8 particles/ml. The average size of the nanoparticles in healthy individuals was 49.05±32.87 nm and that of exosomes in oral cancer patients was 95.36±36.76 nm, which is much larger than that of healthy Individuals.

Atomic force microscopy

The 3D topographical images of the nanoparticle in the Oral fluids of both healthy individuals and oral cancer patients appeared as circular bulging structures, but the height of the particles in oral cancer patients was larger than the height of those in healthy individuals.

Enzyme linked immunosorbent analysis (ELISA)

Oral fluids collected from oral cancer patients (n=36) and health individuals (n=25) was evaluated for amount of exosomal proteins CD63, CD9 and CD81. The concentration of CD63 in the exosomes in the oral fluids was higher in oral cancer patients (234±79 pg/ml) compared with that of health individuals (176±42.3 pg/ml) however there was no significant difference (p=0.2).

The concentration of CD81 in exosomes in the oral fluids of patients with oral squamous cell carcinoma was 61.1±37 pg/ml, and that concentration of CD81 in the exosomes of oral fluids of healthy individuals was 201±79.5 pg/ml. This difference is statistically significant (p=0.032). The concentration of CD9 in the exosomes of oral fluids of oral cancer patients was 104.1±18 pg/ml, while that in the exosomes in the oral fluids of healthy individuals was 152.9±24.4 pg /ml. This difference is not statistically significant.

Western blot

In oral cancer patients the exosomal pellets obtained from the oral fluids showed the presence of the glycosylated form of CD63 as a prominent band at 53Kd. With regard to CD81, the exosomes obtained from the oral fluids of oral cancer patients and healthy individuals showed a band at the expected 26 kDa area of the protein. The exosomes obtained from the oral fluid of both oral cancer patients and healthy individuals showed a specific band at 28kDa area to represent CD9. However, in oral cancer patients the intensity of the band was lower than that in healthy individuals.

Mathivanan et al also found a significant increase in the expression of CD63 and a decrease in the expression of CD9 and CD81 in exosomes present in the saliva of oral cancer patients compared to that of the exosomes in the saliva of healthy individuals. ⁶ Exosomes are recognized by the molecular biomarkers that they express; namely, CD63, CD9, CD81, Alix, TSG101 and hsp70. ¹⁵

Proteins that are encapsulated and transported by exosomes are responsible for regulating the fusion, migration, and adhesion to the target cells. These proteins are transmembrane proteins such as CD9, CD63, CD81 and CD82 molecular chaperones Hsp70 and Hsp90, and multi-capsule synthesis proteins TSG101 and ALIX. ¹⁶ ^– ²⁰ The miRNAs in the exosomes are of higher concentration and greater stability while they are in circulation as they are within encapsulated vesicles. ¹¹ ^, ²¹ ^, ²² The proteases and RNAases in circulation cannot act on the exosomal proteins; hence they have a longer half-life than the free molecules. ¹⁹ Exosomes are enriched in cholesterol, diglycerides, glycerophospholipids, phospholipids and sphinolipids or glyceromides. ²³

Exosomes in oral potentially malignant disorders

Li et al. isolated mesenchymal stem cells from the clinical tissue samples of normal oral mucosal tissues, dysplastic oral lesions and oral squamous cell carcinoma tissue. The exosomes were isolated from the Mesenchymal stem cells and a microarray analysis of the exosomes showed that miR 8485 was differentially expressed in the three groups. The miRNA-8485, when transfected into dysplastic oral mucosal cell lines (DOK) as well as tongue squamous cell carcinoma cell line SCC15, caused rapid growth, promoted migration and invasion of the cells. ²⁴

Wang et al. found that when MSC-EV-miR-185 was pasted onto buccal lesions in dimethylbenzanthracene (DMBA) induced Oral Potentially Malignant disorders (OPMD) model it remarkably attenuated the severity of inflammation and significantly decreased the incidence and the number of dysplastic characteristics in the OPMD tissue. Also, these cells showed a low immunohistochemical expression of PCNA and CD 31. By activating caspase 3 and 9 of the apoptotic pathway, the miR-185 targeted the Akt pathway. ²⁵

Exosomes in oral submucous fibrosis

Oral submucous fibrosis is a multifactorial precancer disorder that is caused by chewing areca nuts. Liu et al. isolated adipose-derived mesenchymal stem cell exosomes from the fibroblasts of oral submucous fibrosis patients and normal individuals. These ADSC-Exos were found to be positive for CD63. The mRNA expression levels of COLIA 1 and COLIA III were down regulated in fibroblasts that were stimulated with both TGF- Beta and ADSC-Exos in the culture media. Similarly, the expression of Collagen I and Collagen III was downregulated in fibroblasts that were treated with both TGF Beta and ADSC-exosomes. The ADSC-exosomes inhibited the p38 MAPK signalling pathway and reduced the expression of collagen I and Collagen III.

However, the expression levels of matrix metalloproteinase (MMP)1 and MMP3 were significantly upregulated in fibroblasts when they were stimulated with both TGF beta and ADSC-Exosomes in the culture media. With the ability of ADSC-Exos to inhibit the P38 MAPK signaling pathway, this biomarker can serve as remarkable treatment option for Oral submucous fibrosis. ²⁶

In another study, Zhou et al. isolated exosomal long non-coding RNA ADAMTS9-AS2 from tissue samples of oral submucous fibrosis and oral squamous cell carcinomas. miRNAs regulated by lncRNA ADAMTS9-AS2 enriched the metabolic pathway, epithelial mesenchymal transition, p13K-Akt pathway and pathways of cancer and enhanced the malignant potential of OSF. ADAMTS9-AS2 plays a crucial role in altering the cell microenvironment during the carcinogenesis process of oral submucous fibrosis and, thus is an ideal marker for early diagnosis of OSCC in oral submucous fibrosis. ²⁷

Exosomes in oral lichen planus

Oral lichen planus is a chronic inflammatory disease of the oral mucosa with an unknown etiology which is characterized by abnormal activity in the T-cell mediated immune response and is also regarded as a “potentially precancerous disorder ^”. ²⁸ ^, ²⁹

Byun et al. ³⁰ isolated exosomes from the lesions of oral lichen planus and from saliva of 16 patients and eight age-matched normal individuals. The miRNA microarray analysis showed that there were 21 miRNAs that showed a 2-fold increase in the saliva samples of oral lichen planus compared to that in normal individuals. Among all the miRNAs that were identified, hsa-miR4484, hsa-miR1246 and hsa-miR1290 were found to be upregulated in the salivary exosomes of oral lichen planus patients. The miRNA 4484 can target a multitude of genes and initiate their translation into proteins that alter the cellular mechanisms.

Exosomes in oral cancer

Exosomes derived from oral cancer are saucer-like in shape with a membranous structure. The size of the exosomes in the saliva of oral cancer patients can be as large as 400 nm in diameter. ¹⁴ Western blot can detect proteins CD63, Rab 5, CD9 and Alix in the exosomes derived from oral cancer patients. Exosomes derived from oral cancer cell lines contain close to 267 proteins. ³¹

Exosomes are involved in several cellular mechanisms of oral cancers such as tumor growth, invasion, metastasis and chemoresistance ⁹ ^, ³² ( Figure 2). Exosomes secreted by neoplastic cells into the tumor microenvironment (TME) play a vital role in tumor growth, invasion and metastasis. ³³ Exosomes are also found to promote epithelial-mesenchymal transition during the progression of squamous cell carcinomas of the tongue. ³⁴ ^, ³⁵ In the study done by Veread et al., the exosomes isolated from HSC 3 cancer cell extracts when tested with ELISA also showed the presence of CAV-1 along with CD 63, CD 9 and CD 81. ³⁴ Dayan et al., in their study identified cancer derived exosomes by the presence of TSGO1, with EMT epithelial–mesenchymal transition process and the trans differentiation of fibroblast-to-CAF-like cell in the TME and suggested that molecular cross talk can be exploited to design therapeutic strategies. ³⁵

Wang et al. found that in oral cancer patients with lymphatic metastasis, exosomal laminin 332 was highly expressed. ³⁶ Theodoraki et al. ³⁷ found that exosomal PD-L 1 was associated with the clinical stage of oral cancer. Rabinowitz also found exosomes enriched with miRNA in the tissue samples of tongue oral squamous cell carcinomas. ³⁸ The exosomes in saliva from oral cancer patients are larger compared to that of normal exosomes. The density of CD63 in the exosomes of oral cancer patients is markedly increased when compared with normal exosomes. ³⁹ Yet the density of the other surface markers of exosomes CD9 and CD81 is significantly reduced in saliva of oral cancer patients when compared with that of normal individuals. ¹⁴

Exosomes from hypoxic oral squamous cell carcinoma cells are found to deliver the miR-21 to tumor OSCC cells. This promotes a prometastatic behavior among tumor cells. ⁴⁰ Exosomes can also spread the invasive potential to non-invasive cells by transferring oncogenic miRNAs. Highly invasive tongue cancer cells can release exosomes containing miR-200-3p that will prevent the expression of CHD 9 and WRN in non-invasive cells and confer an invasive potential to these cells as well. ⁴¹ Qadir et al. found that CEP55 (a centrosomal protein) was present in all the exosomes released from cell lines of Head and Neck Carcinoma cells and absent in the exosomes released from normal oral keratinocytes. ⁴²

Liu et al. found that oral squamous cell carcinoma cells released chemo resistant exosomes which induce cisplatin resistance in OSCC. These exosomes can upregulate miR-21 and downregulate the expression of phosphate and tensin homolog and programmed cell death. ⁴³

Langevi et al. found that salivary exosomes expressed elevated levels of miRNA 486-5p in oropharyngeal squamous cell carcinomas compared to controls. ⁴⁴ He et al. isolated salivary exosomes from oral squamous cell carcinoma patients and quantified them by NTA and characterized them by TEM and found that salivary exosomes had higher level of miR24-3p in oral squamous cell carcinoma patients. ⁴⁵

Early-stage tumors release exosomes that contain several tumor markers into saliva and hence they can serve as non-invasive, efficient diagnostic tools. ⁴⁶ Faur et al. found that miR-10b-5p, miR-486-5p, miR-24-3p and miR-200a in the exosomes of saliva are the most useful salivary biomarkers of head and neck cancer. ⁴⁷ In addition other biomarkers such as A2M, HPa, MUC5B, LGALS3BP, IGHA1, PIP, PKM1/M2, GAPDH, have also be identified in the salivary exosomes derived from oral cancer patients. ⁴⁸ Moreover, Human Papilloma virus has been detected in the salivary exosomes of patients with oro-pharyngeal carcinomas. ⁴⁹

Exosomal miR-29a-3p derived from OSCC cells can promote proliferation and invasion of OSCC cells by enhancing the polarization of M2-subtype of macrophages, the tumor associated macrophages (TAMs). ⁵⁰ When OSCC cells release exosomes that contain THBS1, they communicate with M1 subtype of macrophages and transform them into TAMs. These TAMs can now promote migration of OSCC cells. ⁵¹

Zhu et al. found that oral cancer cells released exosomes that contained TGF-beta. these exosomes are internalized by natural killer cells in the microenvironment. During the early stages, the proteins in the exosomes enhanced the function of the NK cells. Yet, with a longer incubation time, the TGF-beta gradually inhibited the cellular cytotoxicity of NK cells. The killer function of natural killer cells also decreased. A PANTHER protein class analysis showed that there is salient enrichment of proteins related to localization and adhesion of exosomes to their recipient cells. Then the exosomes fuse with the cell membrane of the recipient cell and transfer their contents in the recipient cell. ⁵²

Exosomes derived from oral cancer cell contain NAP1 that enhanced the cytotoxicity of NK cells. ⁵³ Exosomes derived from oral squamous cell carcinomas also contain the biomarker EGFR. ⁵⁴ Most often EGFR and CD 9 are in the same exosome. ⁵⁵ The EGFR secreted by OSCC cells play a vital role in the EMT of epithelial cells. Cetuximab is not able to inhibit the EGFR mediated EMT transition of the transformed OSCC cells. ⁵⁶ Metastatic OSCC cells actively secrete chaperone-rich exosomes that are rich in stress re resistant protein HSP. ⁵⁷

Cancer associated fibroblasts

Cancer associated fibroblasts promote tumor progression mainly through actively communicating with cancer cells. CAFs-associated exosomes mediate migration and invasion of OSCC cells. CAF’s derived exosomes exert a stronger effect on upregulation of MMP-3, MMP-9, N-Cadherin and Beta catenin. miR-382-5p are transferred from CAFs to OSCC cells through exosomes. The expression of miR-382-5p in CAFs is elevated by ~3.83 fold compared to that of normal fibroblasts. ⁵⁸ Languino et al. showed that exosomes released from cancer-associated fibroblasts transferred TBRII cells to malignant keratinocytes and activates them to be responsive to the TGF B ligand. ⁵⁹

Exosomes in salivary gland malignancies

Yang et al. in their study found that exosomes loaded with epiregulin from salivary adenoid cystic carcinoma induced epithelial-mesenchymal transition by down regulating the expression of E cadherin. Epilegrin-enriched exosomes derived from salivary adenoid cystic carcinoma can also enhance invasion and metastasis of this tumor. ⁶⁰

Hou et al. found that exosomes-derived salivary adenoid cystic carcinoma 833 cells target the tight junction proteins claudin-1, Zo-1 and beta catenin and enhance migration and invasion of the tumor cells. ⁶¹

Exosomes are an unique biological entity that play an important role in pathogenesis of potentially malignant oral disorders and head and neck cancers ( Tables 1 and 2).

Table 1. Exosomal components in the biology of potentially malignant oral disorders.

Oral leukoplakia
Exosomal component	Target/tissue	Biological function
Exosomal -miR-185 from Mesenchymal stem cells. ²⁵	Buccal lesions in DMBA induces OPMD.	Increased the severity of inflammation. Decreased the number of dysplastic features.

Oral submucous fibrosis
Exosomal component	Target/tissue	Biological function
Human Adipose-derived mesenchymal stem cell exosome. ²⁶	Acts on TGF -β1.	• Reversed the upregulation of Collagen I and Collagen III that is induced by TGF- β1. • Downregulation of COLIA 1 and COL3A I mRNA. • Upregulation of MMP1 and MMP3. • Reversed the upregulation of phosphorylation of p38 that is induced by TGF-.
Exosomal long non-coding RNA ADAMT S 9 -AS2. ²⁷	Acts on the p13K-AKT-Signaling pathway. Acts on the Epithelial – Mesenchymal transition pathway. Act on the metabolic pathways.	• Suppresses the malignant transformation of oral submucous fibrosis • Can also inhibit the cell growth, migration and invasion of oral squamous cell carcinoma cells.

Oral Lichen Planus
Exosomal component	Target/tissue	Biological function
miR-4484. (upregulated). ³⁰	Translation of several genes.	Immune reaction or represents a protective mechanism against a pathological stimulus.

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Table 2. Exosomal components in the biology of head and neck Cancers.

Squamous cell carcinoma
Exosomal component	Target/Tissue	Biological function
Exosomal miRNA 8485 from mesenchymal stem cells of dysplastic oral leukoplakia. ²⁴	Dysplastic oral mucosal cell line and human tongue squamous cell carcinoma cell line.	Promotes proliferation, migration, and invasion of dysplastic oral keratinocytes.
Laminin 332 released from exosomes. ³⁶	Over-expressed.	Associated with lymphatic metastasis.
Programmed death ligand 1 and cytotoxic T lymphocyte associated protein 4 present in the exosomes from head and neck cancer cells. ³⁷	Induce apoptosis of T cells. Inhibit T cell proliferation.	Promotes tumor cell evasion from the immune system.
Exosomal miR 21. ⁴⁰ ^, ⁴³	Hypoxic oral squamous cell carcinoma cells. Down regulates Phosphate and tensin homolog Programmed cell death.	Prometastatic behaviour of tumor cells. Transfers cisplatin-resistance to non-resistant OSCC cell lines.
Exosomal miR 200-3p. ⁴¹	Inhibits the translation of CDH, ETNK1, and WRN.	Enhances the invasive potential of non-invasive tumor cells.
Exosomal CEP55. ⁴²	ESCRT and ALIX binding region.	Cell division.
Salivary exosomal miRNA-486-5p ⁴⁴	Elevated.	• Screening and diagnosis of oral cancers.
Salivary exosomal miR-24-3p. ⁴⁵	Cell cycle regulatory gene PER 1	• Proliferation of Oral Squamous cell carcinoma cells
OSCC Exosomal derived miR 29a-3p. ⁵⁰	Promotes M2 subtype macrophage polarization. These macrophages produce VEGF, PDGF, cytokines and MMPs.	• Promotes proliferation and invasion of Oral Squamous cell carcinoma • Promotes angiogenesis, cancer growth and metastasis.
OSCC Exosomal THBS1 ⁵¹	Acts on M1 subtype of Macrophages.	• Transform macrophages into tumor associated macrophages • Regulates the migration of tumor cells.
Exosomal TGF B. ⁵²	Reduces the expression of surface receptors NKp30 and NKG2D on natural killer lymphocytes.	• Inhibits the cellular cytotoxicity of natural killer lymphocytes.
Exosomal nuclear Kappa B – activating kinase associated protein 1 (NAP -1). ⁵³	Interferon regulatory factor 3-dependent pathway.	• Enhanced the cytotoxicity of natural killer cells.
Exosomal EGFR. ⁵⁵ ^, ⁵⁶	Epithelial mesenchymal transition of epithelial cells.	• Inhibited by anti-EGFR cetuximab
Exosomal stress resistant protein – heat shock protein. ⁵⁷		• Lymph node metastatic oral squamous cell carcinomas.
Exosomes derived from cancer associated fibroblasts. ⁵⁸	Upregulation of MMP-3, MMP-9, N-Cadherin and Beta Catenin.	• Migration and invasion of CAL 27 lines.
Exosomal miR-382-5p derived from cancer-associated fibroblasts. ⁵⁹	RERG/Ras/ERK pathway?	• Migration and invasion of tumor cells.

Salivary gland neoplasms
Exosomal component	Target/Tissue	Biological function
Epiregulin-enriched exosomes Derived from adenoid cystic carcinomas. ⁶⁰	Down regulates the expression of E-Cadherin. Enhance the expression of vascular endothelial growth factor receptor 1 in lung endothelial cells.	• Induces epithelial-mesenchymal transition • Enhances invasion and metastasis • Generates a premetastatic niche at the site of future metastasis.
Exosomes derived from Adenoid cystic carcinoma 883 cells. ⁶¹	Down regulates the proteins of the tight junctions Claudin-1, ZO-1, and catenin.	• Promotes tumor cell migration and invasion.

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Exosomes in oral cancer treatment – drug delivery

Precise targeted delivery of chemotherapeutic drugs is one of the best methods to reduce the toxic side effects of chemotherapy. Exosomes have superior drug delivery properties, such as good stability, allowing them to travel to distant target organs. The hydrophilic core encapsulates water soluble drug molecules. Exosomes are highly biosafe and do not induce an immune response in the body. ⁶² ^, ⁶³ Exosomes can track and monitor tumor progression and drug resistance in real-time giving information on drug heterogeneity. ⁶⁴ A proteome map of human parotid exosomes has also been developed using multi-dimensional protein identification technology, which helps in discovering exosome protein markers related to oral cancer. ⁶⁵

Exosomes can be used as natural drug delivery vehicles for oral cancer. Exosomes can deliver their contents to the target cell by binding to the cell membranes and the receptors present on the surface membrane and then by cytocytosis. ⁶⁶ Exosomal drug loading can either be through three types of a passive methods and four types of active methods. ⁶⁷ ^– ⁷³

One of the passive forms of exosomal drug loading is to transfect the drugs to be loaded into the donor cells and then encapsulate the drugs into the exosomes inside the donor cells. Although the drugs might have a toxic effect on the donor cell, this method is safe and is used in immunotherapeutic treatment for cancer. ⁶⁸ Another method of passive drug loading is to separate and purify the exosomes from the donor cell and mix them with the drug to be loaded. Although the drug loading is slow, the integrity of the exosomal membrane is maintained. ⁶⁷

One of the active methods of loading exosomes with drugs is to prepare a pore in the exosomal membrane by an electrical field and then to allow the therapeutic drug to penetrate the exosomes. By this method, hydrophilic molecules are transported into the hydrophilic core of the exosomes. ⁷⁰ In another active method the exosomes and the drugs are first frozen and then thawed. ⁷³

Exosomes can also serve as carriers of therapeutic small molecules, proteins and nuclei acids for therapeutic application in diseases. Exosomes have an amazing advantage of good biocompatibility, almost non-toxic side effects and can be used as a sound drug delivery system. The lipid bilayer membrane of exosomes protects their contents from degradation and destruction, and they are highly stable in circulation. The small size of exosomes gives them the ability to cross various biological barriers such as the blood – brain barrier and reach the target cell or organ. ⁶⁶

Exosomes carry hydrophilic molecules such as miRNAs. An effective way of cancer treatment would be load the exosomes with miRNAs that can inhibit OSCC progress such as miR-1294, miR- 6887-5p or miR-101-3p. It is revealed that Fe3O4 nanoparticles and a constant magnetic field can induce exosomal miR-21-5p upregulation. This method of a combination of nanomaterials and a magnetic field improves the precise localization of drug, drug retention and the drug half-life and reduces the drug dose that is needed and improves drug efficacy. ⁷⁴ ^, ⁷⁵

Maacha et al. in their review on the role of extracellular vesicles in the tumor microenvironment and in anti-cancer drug resistance deduced that by exploiting their molecular cargo the extracellular vesicles can be developed into efficient drug vehicles for cancer treatment. Bioengineered EV’s loaded with chemotherapeutic agents or ligands which target malignant cells can be used for cancer treatment. ⁷⁶ The presence of CD47 on exosomes produces a signal that protects them from phagocytosis. ⁷⁷ Delivering specific DNA, RNA or proteins via exosomes can be an interesting method of treating oral cancers.

Modifications of the cargo of exosomes to express CD3 antibodies reprograms exosomes to activate T cells, and thereby, exosomes can be engineered to generate allogenic therapeutics with defined immune targeting properties. ⁷⁸

Exosomes have also been recognized as modulators of drug resistance. They can mediate drug resistance by directly exporting of sequestrated cytotoxic drugs and this reduces the effective concentration of the drugs at the target sites. Exosomes can also serve as a sink for immunotherapies, as their surface contain cellular antigens that are a target for monoclonal antibody-based drugs. The bioavailability of these drugs at the tumor site is diminished. ⁷⁶

In addition, exosomes can also communicate drug resistance to cancer cells that are drug sensitive. The presence of some microRNA’s-21 in exosomes was found to promote anticancer drug resistance to cisplatin in oral cancer cell lines. ⁴³ To mitigate exosomes that promote drug resistance, these exosomes are to be specifically removed and the secretion of the beneficial exosomes is to be maintained. ⁷⁶

Challenges in the clinical application of exosomes

One of the challenges application of exosomes in oral cancer therapeutics is that the isolation of exosomes is time consuming, laborious, costly and at times inefficient. The purity and the quality of the exosomes is not sufficient. ⁷⁵ The translation of Exosome based therapeutic vesicles requires large-scale good manufacturing practice production. ⁷⁹

Substantial amount of clinical grade exosomes has been obtained through differential ultra centrifugation and tangential flow filtration. By Tangential flow filtration and size exclusion chromatography large volumes of exosomes can be isolated from cell culture media. ⁸⁰

It is challenging to maintain the stability of the exosomes in saliva for a long period of time. The action of exosomes is also affected by several pre-analysis parameters, that will reduce the efficacy of exosomes in the diagnosis of oral cancers. ⁸¹

For the application of exosomes for oral cancer treatment, the route of exosome delivery, the optimal dose to be employed and the frequency of the treatment needs to be determined to realise the maximum clinical efficiency with minimal side effects. Extensive clinical research with high quality exosomes is necessary to accomplish this. ⁸²

There are strategies to develop exosome-based vaccine for treating oral cancer. Yet, because of their heterogenous origin and the differential effect that the oral cancer derived exosomes exhibit, it is challenging to develop these vaccines. Also, derived exosomes may inhibit anti-tumor mechanisms and promote metastasis and hence will be risky to employ them in vaccine preparation. ⁸³

Conclusion

Exosomes are extracellular messengers that transport and exchange valuable molecules across cells and this has a huge influence on the cellular activity of the recipient cell as well as their microenvironment. An astute evaluation of the components of exosomes will provide a greater insight into the underlying molecular mechanism of the disease process. Exosomes are found in abundance in biofluids such as saliva, which can be readily and easily obtained through non-invasive methods. Salivary exosomes are more stable and can be widely used for the diagnosis and early detection of oral cancers. miRNAs in the exosomes provide molecular and genetic information that can assist in the prognosis and for disease monitoring of oral cancer patients. Further investigation in the area of salivary exosomes, will unravel the biological mechanism of exosomes in the tumorigenesis pathway of oral precancers and cancers. Exosomes are very small and can easily pass through various biological barriers, making them very good delivery vectors for therapeutic drugs as well as to selectively induce DNA’s mRNA and miRNAs into targeted cancer cells.

Data availability

No data are associated with this article.

Funding Statement

The author(s) declared that no grants were involved in supporting this work.

[version 2; peer review: 2 approved

References

1. Pan BT, Teng K, Wu C, et al. : Electron microscopic evidence for externalization of the transferrin receptor in vesicular form in sheep reticulocytes. J. Cell Biol. 1985;101(3):942–948. 10.1083/jcb.101.3.942 [DOI] [PMC free article] [PubMed] [Google Scholar]
2. Johnstone RM: The Jeanne Manery-Fisher Memorial Lecture 1991 Maturation of reticulocytes: formation of exosomes as a mechanism for shedding membrane proteins. Biochem. Cell Biol. 1992;70(3–4):179–190. 10.1139/o92-028 [DOI] [PubMed] [Google Scholar]
3. Kourembanas S: Exosomes: vehicles of intercellular signaling, biomarkers, and vectors of cell therapy. Annu. Rev. Physiol. 2015;77:13–27. 10.1146/annurev-physiol-021014-071641 [DOI] [PubMed] [Google Scholar]
4. Tkach M, Théry C: Communication by Extracellular Vesicles: Where We Are and Where We Need to Go. Cell. 2016 Mar 10;164(6):1226–1232. 10.1016/j.cell.2016.01.043 [DOI] [PubMed] [Google Scholar]
5. Rani S, Ritter T: The Exosome - A Naturally Secreted Nanoparticle and its Application to Wound Healing. Adv. Mater. 2016 Jul;28(27):5542–5552. 10.1002/adma.201504009 [DOI] [PubMed] [Google Scholar]
6. Mathivanan S, Ji H, Simpson RJ: Exosomes: extracellular organelles important in intercellular communication. J. Proteome. 2010 Sep 10;73(10):1907–1920. 10.1016/j.jprot.2010.06.006 [DOI] [PubMed] [Google Scholar]
7. Doyle LM, Wang MZ: Overview of Extracellular Vesicles, Their Origin, Composition, Purpose, and Methods for Exosome Isolation and Analysis. Cells. 2019 Jul 15;8(7):727. 10.3390/cells8070727 [DOI] [PMC free article] [PubMed] [Google Scholar]
8. Johny J, Sreedhar S, Jaseela CR, et al. : Role of exosomes in oral cancer- A review. Int. J. Dent. Sci. 2022;4(1):13–16. [Google Scholar]
9. Zhan C, Yang X, Yin X, et al. : Exosomes and other extracellular vesicles in oral and salivary gland cancers. Oral Dis. 2020 Jul;26(5):865–875. 10.1111/odi.13172.E [DOI] [PubMed] [Google Scholar]
10. Tschuschke M, Kocherova I, Bryja A, et al. : Inclusion Biogenesis, Methods of Isolation and Clinical Application of Human Cellular Exosomes. J. Clin. Med. 2020 Feb 6;9(2):436. 10.3390/jcm9020436 [DOI] [PMC free article] [PubMed] [Google Scholar]
11. Sahu S, Routray S: Assessing the analytical efficacy of TEX in diagnosing oral cancer using a systematic review approach. J. Oral Pathol. Med. 2021 Feb;50(2):123–128. 10.1111/jop.1312 [DOI] [PubMed] [Google Scholar]
12. Valadi H, Ekström K, Bossios A, et al. : Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells. Nat. Cell Biol. 2007 Jun;9(6):654–659. 10.1038/ncb1596 [DOI] [PubMed] [Google Scholar]
13. Wei F, Lin CC, Joon A, et al. : Noninvasive saliva-based EGFR gene mutation detection in patients with lung cancer. Am. J. Respir. Crit. Care Med. 2014 Nov 15;190(10):1117–1126. 10.1164/rccm.201406-1003OC [DOI] [PMC free article] [PubMed] [Google Scholar]
14. Zlotogorski-Hurvitz A, Dayan D, Chaushu G, et al. : Morphological and molecular features of oral fluid-derived exosomes: oral cancer patients versus healthy individuals. J. Cancer Res. Clin. Oncol. 2016 Jan;142(1):101–110. 10.1007/s00432-015-2005-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
15. Simons M, Raposo G: Exosomes--vesicular carriers for intercellular communication. Curr. Opin. Cell Biol. 2009 Aug;21(4):575–581. 10.1016/j.ceb.2009.03.007 [DOI] [PubMed] [Google Scholar]
16. Hemler ME: Tetraspanin proteins mediate cellular penetration, invasion, and fusion events and define a novel type of membrane microdomain. Annu. Rev. Cell Dev. Biol. 2003;19:397–422. 10.1146/annurev.cellbio.19.111301.153609 [DOI] [PubMed] [Google Scholar]
17. Li P, Kaslan M, Lee SH, et al. : Progress in exosome isolation techniques. Annu. Rev. Cell Dev. Biol. 2017a;19:397–422. 10.1146/annurev.cellbio.19.111301.153609 [DOI] [Google Scholar]
18. Hu Q, Su H, Li J, et al. : Clinical applications of exosome membrane proteins. Precis. Clin. Med. 2020 Mar;3(1):54–66. 10.1093/pcmedi/pbaa007 [DOI] [PMC free article] [PubMed] [Google Scholar]
19. Li L, Zhu D, Huang L, et al. : Argonaute 2 complexes selectively protect the circulating microRNAs in cell-secreted microvesicles. PLoS One. 2012;7(10):e46957. 10.1371/journal.pone.0046957 [DOI] [PMC free article] [PubMed] [Google Scholar]
20. Niel G, Porto-Carreiro I, Simoes S, et al. : Exosomes: a common pathway for a specialized function. J. Biochem. 2006 Jul;140(1):13–21. 10.1093/jb/mvj128 [DOI] [PubMed] [Google Scholar]
21. Gallo A, Alevizos I: Isolation of circulating microRNA in saliva. Methods Mol. Biol. 2013;1024:183–190. 10.1007/978-1-62703-453-1_14 [DOI] [PubMed] [Google Scholar]
22. Köberle V, Pleli T, Schmithals C, et al. : Differential stability of cell-free circulating microRNAs: implications for their utilization as biomarkers. PLoS One. 2013 Sep 20;8(9):e75184. 10.1371/journal.pone.0075184 [DOI] [PMC free article] [PubMed] [Google Scholar]
23. Record M, Carayon K, Poirot M, et al. : Exosomes as new vesicular lipid transporters involved in cell-cell communication and various pathophysiologies. Biochim. Biophys. Acta. 2014 Jan;1841(1):108–120. 10.1016/j.bbalip.2013.10.004 [DOI] [PubMed] [Google Scholar]
24. Li W, Han Y, Zhao Z, et al. : Oral mucosal mesenchymal stem cell-derived exosomes: A potential therapeutic target in oral premalignant lesions. Int. J. Oncol. 2019 May;54(5):1567–1578. 10.3892/ijo.2019.4756 [DOI] [PMC free article] [PubMed] [Google Scholar]
25. Wang L, Yin P, Wang J, et al. : Delivery of mesenchymal stem cells-derived extracellular vesicles with enriched miR-185 inhibits progression of OPMD. Artif Cells Nanomed Biotechnol. 2019 Dec;47(1):2481–2491. 10.1080/21691401.2019.1623232 [DOI] [PubMed] [Google Scholar]
26. Liu J, Li F, Liu B, et al. : Adipose-derived mesenchymal stem cell exosomes inhibit transforming growth factor-β1-induced collagen synthesis in oral mucosal fibroblasts. Exp. Ther. Med. 2021 Dec;22(6):1419. 10.3892/etm.2021.10854 [DOI] [PMC free article] [PubMed] [Google Scholar]
27. Zhou S, Zhu Y, Li Z, et al. : Exosome-derived long non-coding RNA ADAMTS9-AS2 suppresses progression of oral submucous fibrosis via AKT signalling pathway. J. Cell. Mol. Med. 2021 Feb;25(4):2262–2273. 10.1111/jcmm.16219 [DOI] [PMC free article] [PubMed] [Google Scholar]
28. Lodi G, Scully C, Carrozzo M, et al. : Current controversies in oral lichen planus: report of an international consensus meeting. Part 2. Clinical management and malignant transformation. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2005 Aug;100(2):164–178. 10.1016/j.tripleo.2004.06.07 [DOI] [PubMed] [Google Scholar]
29. Warnakulasuriya S, Johnson NW, Waal I: Nomenclature and classification of potentially malignant disorders of the oral mucosa. J. Oral Pathol. Med. 2007 Nov;36(10):575–580. 10.1111/j.1600-0714.2007.00582.x [DOI] [PubMed] [Google Scholar]
30. Byun JS, Hong SH, Choi JK, et al. : Diagnostic profiling of salivary exosomal microRNAs in oral lichen planus patients. Oral Dis. 2015 Nov;21(8):987–993. 10.1111/odi.12374 [DOI] [PubMed] [Google Scholar]
31. Zhu X, Qin X, Wang X, et al. : Oral cancer cell-derived exosomes modulate natural killer cell activity by regulating the receptors on these cells. Int. J. Mol. Med. 2020 Dec;46(6):2115–2125. 10.3892/ijmm.2020.4736 [DOI] [PMC free article] [PubMed] [Google Scholar]
32. Whitefield TL: Tumor- derived exosomes and their role in tumor-induced immune suppression. Vaccines. 2016;4:35. 10.3390/vaccines4040035 [DOI] [PMC free article] [PubMed] [Google Scholar]
33. Zhang HG, Grizzle WE: Exosomes: a novel pathway of local and distant intercellular communication that facilitates the growth and metastasis of neoplastic lesions. Am. J. Pathol. 2014 Jan;184(1):28–41. 10.1016/j.ajpath.2013.09.027 [DOI] [PMC free article] [PubMed] [Google Scholar]
34. Vered M, Lehtonen M, Hotakainen L, et al. : Caveolin-1 accumulation in the tongue cancer tumor microenvironment is significantly associated with poor prognosis: an in-vivo and in-vitro study. BMC Cancer. 2015 Jan 30;15:25. 10.1186/s12885-015-1030-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
35. Dayan D, Salo T, Salo S, et al. : Molecular crosstalk between cancer cells and tumor microenvironment components suggests potential targets for new therapeutic approaches in mobile tongue cancer. Cancer Med. 2012 Oct;1(2):128–140. 10.1002/cam4.24 [DOI] [PMC free article] [PubMed] [Google Scholar]
36. Wang SH, Liou GG, Liu SH, et al. : Laminin γ2-enriched extracellular vesicles of oral squamous cell carcinoma cells enhance in vitro lymphangiogenesis via integrin α3-dependent uptake by lymphatic endothelial cells. Int. J. Cancer. 2019 Jun 1;144(11):2795–2810. 10.1002/ijc.32027 [DOI] [PubMed] [Google Scholar]
37. Theodoraki MN, Yerneni SS, Hoffmann TK, et al. : Clinical Significance of PD-L1 ⁺ Exosomes in Plasma of Head and Neck Cancer Patients. Clin. Cancer Res. 2018 Feb 15;24(4):896–905. 10.1158/1078-0432.CCR-17-2664.905 [DOI] [PMC free article] [PubMed] [Google Scholar]
38. Rabinowits G, Bowden M, Flores LM, et al. : Comparative Analysis of MicroRNA Expression among Benign and Malignant Tongue Tissue and Plasma of Patients with Tongue Cancer. Front. Oncol. 2017 Aug 29;7:191. 10.3389/fonc.2017.00191 [DOI] [PMC free article] [PubMed] [Google Scholar]
39. Sharma S, Gillespie BM, Palanisamy V, et al. : Quantitative nanostructural and single-molecule force spectroscopy biomolecular analysis of human-saliva-derived exosomes. Langmuir. 2011 Dec 6;27(23):14394–14400. 10.1021/la2038763 [DOI] [PMC free article] [PubMed] [Google Scholar]
40. Sakha S, Muramatsu T, Ueda K, et al. : Exosomal microRNA miR-1246 induces cell motility and invasion through the regulation of DENND2D in oral squamous cell carcinoma. Sci. Rep. 2016 Dec 8;6:38750. 10.1038/srep38750 [DOI] [PMC free article] [PubMed] [Google Scholar]
41. Kawakubo-Yasukochi T, Morioka M, Hazekawa M, et al. : miR-200c-3p spreads invasive capacity in human oral squamous cell carcinoma microenvironment. Mol. Carcinog. 2018 Feb;57(2):295–302. 10.1002/mc.2274 [DOI] [PubMed] [Google Scholar]
42. Qadir F, Aziz MA, Sari CP, et al. : Transcriptome reprogramming by cancer exosomes: identification of novel molecular targets in matrix and immune modulation. Mol. Cancer. 2018 Jul 16;17(1):97. 10.1186/s12943-018-0846-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
43. Liu T, Chen G, Sun D, et al. : Exosomes containing miR-21 transfer the characteristic of cisplatin resistance by targeting PTEN and PDCD4 in oral squamous cell carcinoma. Acta Biochim. Biophys. Sin. Shanghai. 2017 Sep 1;49(9):808–816. 10.1093/abbs/gmx078 [DOI] [PubMed] [Google Scholar]
44. Langevin S, Kuhnell D, Parry T, et al. : Comprehensive microRNA-sequencing of exosomes derived from head and neck carcinoma cells in vitro reveals common secretion profiles and potential utility as salivary biomarkers. Oncotarget. 2017 Jul 27;8(47):82459–82474. 10.18632/oncotarget.19614 [DOI] [PMC free article] [PubMed] [Google Scholar]
45. He L, Ping F, Fan Z, et al. : Salivary exosomal miR-24-3p serves as a potential detective biomarker for oral squamous cell carcinoma screening. Biomed. Pharmacother. 2020 Jan;121:109553. 10.1016/j.biopha.2019.109553 [DOI] [PubMed] [Google Scholar]
46. Nonaka T, Wong DTW: Salivary exosomics in cancer. Molecular characterization of cancer-derived exosomes in saliva. Enzyme. 2017;42:125–151. 10.1016/bs.enz.2017.08.002 [DOI] [PMC free article] [PubMed] [Google Scholar]
47. Faur CI, Rotaru H, Osan C, et al. : Salivary exosomal microRNAs as biomarkers for head and neck cancer detection-a literature review. Maxillofac. Plast. Reconstr. Surg. 2021 Jun 30;43(1):19. 10.1186/s40902-021-00303-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
48. Winck FV, Prado Ribeiro AC, Ramos Domingues R, et al. : Insights into immune responses in oral cancer through proteomic analysis of saliva and salivary extracellular vesicles. Sci. Rep. 2015;5:16305. 10.1038/srep16305 [DOI] [PMC free article] [PubMed] [Google Scholar]
49. Wang z, Li F, Rufo J, et al. : Acoustofluidic salivary exosome isolation a liquid biopsy compatible approach for human papillomavirus associated oropharyngeal cancer detaction. J. Mol. Diagn. 2020;22:50–59. 10.1016/j.jmoldx.2019.08.004 [DOI] [PMC free article] [PubMed] [Google Scholar]
50. Cai J, Qiao B, Gao N, et al. : Oral squamous cell carcinoma-derived exosomes promote M2 subtype macrophage polarization mediated by exosome-enclosed miR-29a-3p. Am. J. Physiol. Cell Physiol. 2019 May 1;316(5):C731–C740. 10.1152/ajpcell.00366.2018 [DOI] [PubMed] [Google Scholar]
51. Xiao M, Zhang J, Chen W, et al. : M1-like tumor-associated macrophages activated by exosome-transferred THBS1 promote malignant migration in oral squamous cell carcinoma. J. Exp. Clin. Cancer Res. 2018 Jul 9;37(1):143. 10.1186/s13046-018-0815-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
52. Zhu X, Qin X, Wang X, et al. : Oral cancer cell-derived exosomes modulate natural killer cell activity by regulating the receptors on these cells. Int. J. Mol. Med. 2020 Dec;46(6):2115–2125. 10.3892/ijmm.2020.4736 [DOI] [PMC free article] [PubMed] [Google Scholar]
53. Wang Y, Qin X, Zhu X, et al. : Oral cancer-derived exosomal NAP1 enhances cytotoxicity of natural killer cells via the IRF-3 pathway. Oral Oncol. 2018 Jan;76:34–41. 10.1016/j.oraloncology.2017.11.024 [DOI] [PMC free article] [PubMed] [Google Scholar]
54. Huang SH, Li Y, Zhang J, et al. : Epidermal growth factor receptor-containing exosomes induce tumor-specific regulatory T cells. Cancer Investig. 2013 Jun;31(5):330–335. 10.3109/07357907.2013.789905 [DOI] [PubMed] [Google Scholar]
55. Fujiwara T, Eguchi T, Sogawa C, et al. : Carcinogenic epithelial-mesenchymal transition initiated by oral cancer exosomes is inhibited by anti-EGFR antibody cetuximab. Oral Oncol. 2018 Nov;86:251–257. 10.1016/j.oraloncology.2018.09.030 [DOI] [PubMed] [Google Scholar]
56. Fujiwara T, Eguchi T, Sogawa C, et al. : Anti-EGFR antibody cetuximab is secreted by oral squamous cell carcinoma and alters EGF-driven mesenchymal transition. Biochem. Biophys. Res. Commun. 2018 Sep 10;503(3):1267–1272. 10.1016/j.bbrc.2018.07.035 [DOI] [PubMed] [Google Scholar]
57. Ono K, Eguchi T, Sogawa C, et al. : HSP-enriched properties of extracellular vesicles involve survival of metastatic oral cancer cells. J. Cell. Biochem. 2018 Sep;119(9):7350–7362. 10.1002/jcb.27039 [DOI] [PubMed] [Google Scholar]
58. Sun LP, Xu K, Cui J, et al. : Cancer-associated fibroblast-derived exosomal miR-382-5p promotes the migration and invasion of oral squamous cell carcinoma. Oncol. Rep. 2019 Oct;42(4):1319–1328. 10.3892/or.2019.7255 [DOI] [PMC free article] [PubMed] [Google Scholar]
59. Languino LR, Singh A, Prisco M, et al. : Exosome-mediated transfer from the tumor microenvironment increases TGFβ signaling in squamous cell carcinoma. Am. J. Transl. Res. 2016 May 15;8(5):2432–2437. [PMC free article] [PubMed] [Google Scholar]
60. Yang WW, Yang LQ, Zhao F, et al. : Epiregulin Promotes Lung Metastasis of Salivary Adenoid Cystic Carcinoma. Theranostics. 2017 Aug 23;7(15):3700–3714. 10.7150/thno.19712 [DOI] [PMC free article] [PubMed] [Google Scholar]
61. Hou J, Wang F, Liu X, et al. : Tumor-derived exosomes enhance invasion and metastasis of salivary adenoid cystic carcinoma cells. J. Oral Pathol. Med. 2018 Feb;47(2):144–151. 10.1111/jop.12654 [DOI] [PubMed] [Google Scholar]
62. Ha D, Yang N, Nadithe V: Exosomes as therapeutic drug carriers and delivery vehicles across biological membranes: current perspectives and future challenges. Acta Pharm. Sin. B. 2016 Jul;6(4):287–296. 10.1016/j.apsb.2016.02.001 [DOI] [PMC free article] [PubMed] [Google Scholar]
63. Jiang XC, Gao JQ: Exosomes as novel bio-carriers for gene and drug delivery. Int. J. Pharm. 2017 Apr 15;521(1-2):167–175. 10.1016/j.ijpharm.2017.02.038 [DOI] [PubMed] [Google Scholar]
64. Balasaheb Mali S, Dahivelkar S: Liquid biopsy = Individualized cancer management: Diagnosis, monitoring treatment and checking recurrence and metastasis. Oral Oncol. 2021 Dec;123:105588. 10.1016/j.oraloncology.2021.105588 [DOI] [PubMed] [Google Scholar]
65. Principe S, Hui AB, Bruce J, et al. : Tumor-derived exosomes and microvesicles in head and neck cancer: implications for tumor biology and biomarker discovery. Proteomics. 2013 May;13(10-11):1608–1623. 10.1002/pmic.201200533 [DOI] [PubMed] [Google Scholar]
66. Liu H, Huang Y, Huang M, et al. : Current Status, Opportunities, and Challenges of Exosomes in Oral Cancer Diagnosis and Treatment. Int. J. Nanomedicine. 2022 Jun 16;17:2679–2705. 10.2147/IJN.S365594 [DOI] [PMC free article] [PubMed] [Google Scholar]
67. Sun D, Zhuang X, Xiang X, et al. : A novel nanoparticle drug delivery system: the anti-inflammatory activity of curcumin is enhanced when encapsulated in exosomes. Mol. Ther. 2010 Sep;18(9):1606–1614. 10.1038/mt.2010.105 [DOI] [PMC free article] [PubMed] [Google Scholar]
68. Pascucci L, Coccè V, Bonomi A, et al. : Paclitaxel is incorporated by mesenchymal stromal cells and released in exosomes that inhibit in vitro tumor growth: a new approach for drug delivery. J. Control. Release. 2014 Oct 28;192:262–270. 10.1016/j.jconrel.2014.07.042 [DOI] [PubMed] [Google Scholar]
69. Zeelenberg IS, Ostrowski M, Krumeich S, et al. : Targeting tumor antigens to secreted membrane vesicles in vivo induces efficient antitumor immune responses. Cancer Res. 2008 Feb 15;68(4):1228–1235. 10.1158/0008-5472.CAN-07-3163 [DOI] [PubMed] [Google Scholar]
70. Johnsen KB, Gudbergsson JM, Skov MN, et al. : Evaluation of electroporation-induced adverse effects on adipose-derived stem cell exosomes. Cytotechnology. 2016 Oct;68(5):2125–2138. 10.1007/s10616-016-9952-7 [DOI] [PMC free article] [PubMed] [Google Scholar]
71. Fuhrmann G, Serio A, Mazo M, et al. : Active loading into extracellular vesicles significantly improves the cellular uptake and photodynamic effect of porphyrins. J. Control. Release. 2015;205:35–44. 10.1016/j.jconrel.2014.11.029 [DOI] [PubMed] [Google Scholar]
72. Kim MS, Haney MJ, Zhao Y, et al. : Development of exosome-encapsulated paclitaxel to overcome MDR in cancer cells. Nanomedicine. 2016 Apr;12(3):655–664. 10.1016/j.nano.2015.10.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
73. Sato YT, Umezaki K, Sawada S, et al. : Engineering hybrid exosomes by membrane fusion with liposomes. Sci. Rep. 2016 Feb 25;6:21933. 10.1038/srep21933 [DOI] [PMC free article] [PubMed] [Google Scholar]
74. Wu D, Kang L, Tian J, et al. : Exosomes Derived from Bone Mesenchymal Stem Cells with the Stimulation of Fe ₃O ₄ Nanoparticles and Static Magnetic Field Enhance Wound Healing Through Upregulated miR-21-5p. Int. J. Nanomedicine. 2020 Oct 19;15:7979–7993. 10.2147/IJN.S275650 [DOI] [PMC free article] [PubMed] [Google Scholar]
75. Chen Y, Hou S: Application of magnetic nanoparticles in cell therapy. Stem Cell Res. Ther. 2022;13:135. 10.1186/s13287-022-02808-0 [DOI] [PMC free article] [PubMed] [Google Scholar]
76. Maacha S, Bhat AA, Jimenez L, et al. : Extracellular vesicles-mediated intercellular communication: roles in the tumor microenvironment and anti-cancer drug resistance. Mol. Cancer. 2019 Mar 30;18(1):55. 10.1186/s12943-019-0965-7 [DOI] [PMC free article] [PubMed] [Google Scholar]
77. Kamerkar S, LeBleu VS, Sugimoto H, et al. : Exosomes facilitate therapeutic targeting of oncogenic KRAS in pancreatic cancer. Nature. 2017 Jun 22;546(7659):498–503. 10.1038/nature22341 [DOI] [PMC free article] [PubMed] [Google Scholar]
78. Cheng Q, Shi X, Han M, et al. : Reprogramming Exosomes as Nanoscale Controllers of Cellular Immunity. J. Am. Chem. Soc. 2018 Dec 5;140(48):16413–16417. 10.1021/jacs.8b10047 [DOI] [PMC free article] [PubMed] [Google Scholar]
79. Kalluri R, McAndrews KM: The role of extracellular vesicles in cancer. Cell. 2023 Apr 13;186(8):1610–1626. 10.1016/j.cell.2023.03.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
80. Dooley K, McConnell RE, Xu K, et al. : A versatile platform for generating engineered extracellular vesicles with defined therapeutic properties. Mol. Ther. 2021 May 5;29(5):1729–1743. 10.1016/j.ymthe.2021.01.020.) [DOI] [PMC free article] [PubMed] [Google Scholar]
81. Taylor DD, Shah S: Methods of isolating extracellular vesicles impact down-stream analyses of their cargoes. Methods. 2015 Oct 1;87:3–10. 10.1016/j.ymeth.2015.02.019 [DOI] [PubMed] [Google Scholar]
82. Butreddy A, Kommineni N, Dudhipala N: Exosomes as Naturally Occurring Vehicles for Delivery of Biopharmaceuticals: Insights from Drug Delivery to Clinical Perspectives. Nanomaterials (Basel). 2021 Jun 3;11(6):1481. 10.3390/nano11061481 [DOI] [PMC free article] [PubMed] [Google Scholar]
83. Stremersch S, De Smedt SC, Raemdonck K: Therapeutic and diagnostic, applications of extracellular vesicles. J. Control. Release. 2016;244:167–183. 10.1016/j.jconrel.2016.07.054 [DOI] [PubMed] [Google Scholar]

F1000Res. 2023 Nov 30. doi: 10.5256/f1000research.156624.r223740

Reviewer response for version 2

Jiji George ¹

Monica et al has presented a comprehensive report on Exosomes, their origin, role in different disease conditions ranging from immunologic diseases to cancer. The authors have described the molecular characteristics of exosomes and the different methods of identification. The role of various components of the exosomes in the carcinogenic pathway is expounded in the manuscript. The implication of salivary exosomes in oral cancer diagnostics is highlighted. The benefits of drug delivery utilizing exosomes is explained explicitly.

Strength: The authors have analyzed data from relevant scientific literature and have systematically presented the way in which exosomes are mediators of intercellular communications in premalignant and malignant oral lesions. In addition, the limitations and challenges encountered in the clinical application of exosomes is also described.

I feel this manuscript can be approved in the present format.

Is the review written in accessible language?

Yes

Are all factual statements correct and adequately supported by citations?

Yes

Are the conclusions drawn appropriate in the context of the current research literature?

Yes

Is the topic of the review discussed comprehensively in the context of the current literature?

Yes

Reviewer Expertise:

Oral cancer

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

F1000Res. 2023 Oct 25. doi: 10.5256/f1000research.156624.r212100

Reviewer response for version 2

Ajaz A Bhat ¹

I have no further comments to make.

Is the review written in accessible language?

Yes

Are all factual statements correct and adequately supported by citations?

Yes

Are the conclusions drawn appropriate in the context of the current research literature?

Partly

Is the topic of the review discussed comprehensively in the context of the current literature?

Partly

Reviewer Expertise:

Cancer Biology, Immunology, Obesity

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.

F1000Res. 2023 Jun 29. doi: 10.5256/f1000research.139868.r177886

Reviewer response for version 1

Ajaz A Bhat ¹

Main Findings:

The review by Solomon et al., focuses on the role of exosomes, extracellular vesicles that mediate intercellular communication, in the pathogenesis of potentially malignant oral lesions and head and neck cancers. The authors discuss the molecular characteristics of exosomes, highlighting their resilience due to their lipid bilayer membrane and their capacity to transfer biological material, such as miRNA, mRNA, long non-coding RNA, DNA, proteins, and lipids, between cells. They emphasize the importance of exosomes in tumor growth, invasion, and metastasis, and their potential use in diagnosing disease activity. The review also explores the potential of using exosomes as therapeutic vectors due to their size and ability to traverse biological barriers.

Strengths:

The review provides a comprehensive discussion on the emerging role of exosomes in the context of potentially malignant oral lesions and head and neck cancers, a relatively novel area of research.
It delves into the molecular and genetic information carried by exosomes, thereby providing deep insights into their functioning and influence on cancer cells.
The review brings to light the potential of exosomes as biomarkers, which is crucial for early diagnosis and personalized treatment strategies.
It also explores the potential use of exosomes as therapeutic delivery vectors, which opens a new avenue in the treatment of these types of cancers.

Limitations:

The title might benefit from minor rephrasing to improve readability. For example: "Exosomes: Mediators of Cellular Communication in Potentially Malignant Oral Lesions and Head and Neck Cancers" or "The Role of Exosomes in Cellular Communication: Implications for Potentially Malignant Oral Lesions and Head and Neck Cancers."
Important literature is missing ¹ ^, ². Authors should cite these and many other important recent references. Readers might benefit from references to key studies that have shown the importance of exosomes in potentially malignant oral lesions and head and neck cancers.
It does not address potential challenges or limitations in utilizing exosomes for diagnosis or therapy, which would provide a more balanced perspective.
Authors should have at least one or two figures in the paper.
Although the conclusion acknowledges the need for further investigation in the area of salivary exosomes, it could also discuss potential challenges in this line of research or any practical barriers to using exosomes as diagnostic markers or therapeutic vectors.
Rather than simply stating the need for more research, the authors could suggest specific areas for future study or the kinds of experiments that could be valuable in this field.

English Language:

The language is generally clear and well-written. However, there are some phrases that could be reworded for clarity and flow. For instance, "Exosomes provide a multitude of molecular and genetic information and have become valuable indicators of disease activity at the cellular level" could be reworded to "Exosomes, rich in molecular and genetic information, have emerged as valuable indicators of cellular disease activity." There are many such instances.

Is the review written in accessible language?

Yes

Are all factual statements correct and adequately supported by citations?

Yes

Are the conclusions drawn appropriate in the context of the current research literature?

Partly

Is the topic of the review discussed comprehensively in the context of the current literature?

Partly

Reviewer Expertise:

Cancer Biology, Immunology

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

References

1. : The role of extracellular vesicles in cancer. Cell .2023;186(8) : 10.1016/j.cell.2023.03.010 1610-1626 10.1016/j.cell.2023.03.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
2. : Extracellular vesicles-mediated intercellular communication: roles in the tumor microenvironment and anti-cancer drug resistance. Mol Cancer .2019;18(1) : 10.1186/s12943-019-0965-7 55 10.1186/s12943-019-0965-7 [DOI] [PMC free article] [PubMed] [Google Scholar]

F1000Res. 2023 Sep 21.

Monica Charlotte Solomon ¹

The authors thank the reviewer's for their suggestions and recommendation. Thank you for your time and patience.

The title might benefit from minor rephrasing to improve readability. For example: "Exosomes: Mediators of Cellular Communication in Potentially Malignant Oral Lesions and Head and Neck Cancers" or "The Role of Exosomes in Cellular Communication: Implications for Potentially Malignant Oral Lesions and Head and Neck Cancers."

The title of the manuscript has been corrected as per the suggestion.
Important literature is missing ¹ ^, ² . Authors should cite these and many other important recent references. Readers might benefit from references to key studies that have shown the importance of exosomes in potentially malignant oral lesions and head and neck cancers.

The recommended references have been included in the manuscript.
It does not address potential challenges or limitations in utilizing exosomes for diagnosis or therapy, which would provide a more balanced perspective.

The potential limitation of utilizing exosomes for diagnosis and therapy has been addressed in the manuscript.
Authors should have at least one or two figures in the paper.

Figures have been included in the manuscript.
Although the conclusion acknowledges the need for further investigation in the area of salivary exosomes, it could also discuss potential challenges in this line of research or any practical barriers to using exosomes as diagnostic markers or therapeutic vectors.

The practical barriers has been included in the manuscript.
Rather than simply stating the need for more research, the authors could suggest specific areas for future study or the kinds of experiments that could be valuable in this field.

This has been included in the manuscript.

F1000Res. 2023 Jun 26. doi: 10.5256/f1000research.139868.r177869

Reviewer response for version 1

John W Barrett ¹

The authors review the literature surrounding exosomes generally and more specifically the role of exosomes in oral cancer. Although this manuscript is presented as a Review it reads more like a list of observations or facts. The authors provide two organized tables outlining the exosomal components in the biology of malignant disorders (table 1) or head and neck cancers (table 2) but there is overlap. For example, the first example in Table 1 (Oral Disorders) is dysplastic oral mucosal cell line and human tongue squamous cell carcinoma cell line which should properly be in Table 2 (head and neck cancers).

Minor issues:

The first sentence of the Introduction is clearly untrue. I am not sure what the authors meant to say but to state that exosomes were first described in 2014 is incorrect by about 40 years. Exosomes were first described in the 1970s.
Page 3 TEM section. This section contains a single sentence, and it requires a reference. And in the same section what are the pellets that the authors are referring to?
Page 3 ELISA section. The authors report the levels of CD63 observed in exosomes from the oral fluids from oral cancer patients compared to normal individuals; however, there is no mention as to whether the differences are statistically significant or how many patients were sampled. Looking at the numbers I would predict that the observed levels overlap and are unlikely to be significantly different. But this may just reflect a small sampling number. Neither is reported but the authors should address this deficiency.
Page 5 paragraph 2. The authors state that “The size of the exosomes in the saliva of oral cancer patients are also larger compared to that of healthy individuals and range from 20-400nm in diameter”. So what are the sizes of healthy individuals for comparison? They must be extremely small if they are less than 20nm.
Page 5, last sentence of paragraph 3. “Early-stage tumors release exosomes that contain several tumor markers into saliva and hence they can serve as non-invasive, efficient diagnostic tools." Ok, that is fine but what are these “several tumor markers”? and how can they serve as diagnostic tools?
On page 5, 5 ^th paragraph the authors state that “hypoxic oral squamous cell carcinoma cells are found to deliver the miR-21 to normal OSCC cells." How is this possible? By definition “normal cells” can’t be OSCC (oral squamous cell carcinoma). Please correct and clarify what you mean.
The authors list several studies that identified numerous miRNAs (9 different miRNAs) in the exosomes of oral cancer patients and only one is shared amongst the reports. A review article should be synthesizing these reports and sifting through the observations to present the reader with the best evidence. That is not clear here.

Is the review written in accessible language?

Yes

Are all factual statements correct and adequately supported by citations?

Yes

Are the conclusions drawn appropriate in the context of the current research literature?

Yes

Is the topic of the review discussed comprehensively in the context of the current literature?

Partly

Reviewer Expertise:

Translational head and neck cancer biology

F1000Res. 2023 Sep 21.

Monica Charlotte Solomon ¹

The authors thank the reviewer for their suggestion and recommendations

The first sentence of the Introduction is clearly untrue. I am not sure what the authors meant to say but to state that exosomes were first described in 2014 is incorrect by about 40 years. Exosomes were first described in the 1970s.

Thank you, this has been corrected in the manuscript.
Page 3 TEM section. This section contains a single sentence, and it requires a reference. And in the same section what are the pellets that the authors are referring to?

The details of the same has been included in the manuscript.
Page 3 ELISA section. The authors report the levels of CD63 observed in exosomes from the oral fluids from oral cancer patients compared to normal individuals; however, there is no mention as to whether the differences are statistically significant or how many patients were sampled. Looking at the numbers I would predict that the observed levels overlap and are unlikely to be significantly different. But this may just reflect a small sampling number. Neither is reported but the authors should address this deficiency.

The details have been included in the manuscript.
Page 5 paragraph 2. The authors state that “The size of the exosomes in the saliva of oral cancer patients are also larger compared to that of healthy individuals and range from 20-400nm in diameter”. So what are the sizes of healthy individuals for comparison? They must be extremely small if they are less than 20nm.

This has been corrected in the manuscript.
Page 5, last sentence of paragraph 3. “Early-stage tumors release exosomes that contain several tumor markers into saliva and hence they can serve as non-invasive, efficient diagnostic tools." Ok, that is fine but what are these “several tumor markers”? and how can they serve as diagnostic tools?

The details of the same has been included.
On page 5, 5 ^th paragraph the authors state that “hypoxic oral squamous cell carcinoma cells are found to deliver the miR-21 to normal OSCC cells." How is this possible? By definition “normal cells” can’t be OSCC (oral squamous cell carcinoma). Please correct and clarify what you mean.

This has been corrected.
The authors list several studies that identified numerous miRNAs (9 different miRNAs) in the exosomes of oral cancer patients and only one is shared amongst the reports. A review article should be synthesizing these reports and sifting through the observations to present the reader with the best evidence. That is not clear here.

The details are provided.

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

No data are associated with this article.

[ref1] 1. Pan BT, Teng K, Wu C, et al. : Electron microscopic evidence for externalization of the transferrin receptor in vesicular form in sheep reticulocytes. J. Cell Biol. 1985;101(3):942–948. 10.1083/jcb.101.3.942 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref2] 2. Johnstone RM: The Jeanne Manery-Fisher Memorial Lecture 1991 Maturation of reticulocytes: formation of exosomes as a mechanism for shedding membrane proteins. Biochem. Cell Biol. 1992;70(3–4):179–190. 10.1139/o92-028 [DOI] [PubMed] [Google Scholar]

[ref3] 3. Kourembanas S: Exosomes: vehicles of intercellular signaling, biomarkers, and vectors of cell therapy. Annu. Rev. Physiol. 2015;77:13–27. 10.1146/annurev-physiol-021014-071641 [DOI] [PubMed] [Google Scholar]

[ref4] 4. Tkach M, Théry C: Communication by Extracellular Vesicles: Where We Are and Where We Need to Go. Cell. 2016 Mar 10;164(6):1226–1232. 10.1016/j.cell.2016.01.043 [DOI] [PubMed] [Google Scholar]

[ref5] 5. Rani S, Ritter T: The Exosome - A Naturally Secreted Nanoparticle and its Application to Wound Healing. Adv. Mater. 2016 Jul;28(27):5542–5552. 10.1002/adma.201504009 [DOI] [PubMed] [Google Scholar]

[ref6] 6. Mathivanan S, Ji H, Simpson RJ: Exosomes: extracellular organelles important in intercellular communication. J. Proteome. 2010 Sep 10;73(10):1907–1920. 10.1016/j.jprot.2010.06.006 [DOI] [PubMed] [Google Scholar]

[ref7] 7. Doyle LM, Wang MZ: Overview of Extracellular Vesicles, Their Origin, Composition, Purpose, and Methods for Exosome Isolation and Analysis. Cells. 2019 Jul 15;8(7):727. 10.3390/cells8070727 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref8] 8. Johny J, Sreedhar S, Jaseela CR, et al. : Role of exosomes in oral cancer- A review. Int. J. Dent. Sci. 2022;4(1):13–16. [Google Scholar]

[ref9] 9. Zhan C, Yang X, Yin X, et al. : Exosomes and other extracellular vesicles in oral and salivary gland cancers. Oral Dis. 2020 Jul;26(5):865–875. 10.1111/odi.13172.E [DOI] [PubMed] [Google Scholar]

[ref10] 10. Tschuschke M, Kocherova I, Bryja A, et al. : Inclusion Biogenesis, Methods of Isolation and Clinical Application of Human Cellular Exosomes. J. Clin. Med. 2020 Feb 6;9(2):436. 10.3390/jcm9020436 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref11] 11. Sahu S, Routray S: Assessing the analytical efficacy of TEX in diagnosing oral cancer using a systematic review approach. J. Oral Pathol. Med. 2021 Feb;50(2):123–128. 10.1111/jop.1312 [DOI] [PubMed] [Google Scholar]

[ref12] 12. Valadi H, Ekström K, Bossios A, et al. : Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells. Nat. Cell Biol. 2007 Jun;9(6):654–659. 10.1038/ncb1596 [DOI] [PubMed] [Google Scholar]

[ref13] 13. Wei F, Lin CC, Joon A, et al. : Noninvasive saliva-based EGFR gene mutation detection in patients with lung cancer. Am. J. Respir. Crit. Care Med. 2014 Nov 15;190(10):1117–1126. 10.1164/rccm.201406-1003OC [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref14] 14. Zlotogorski-Hurvitz A, Dayan D, Chaushu G, et al. : Morphological and molecular features of oral fluid-derived exosomes: oral cancer patients versus healthy individuals. J. Cancer Res. Clin. Oncol. 2016 Jan;142(1):101–110. 10.1007/s00432-015-2005-3 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref15] 15. Simons M, Raposo G: Exosomes--vesicular carriers for intercellular communication. Curr. Opin. Cell Biol. 2009 Aug;21(4):575–581. 10.1016/j.ceb.2009.03.007 [DOI] [PubMed] [Google Scholar]

[ref16] 16. Hemler ME: Tetraspanin proteins mediate cellular penetration, invasion, and fusion events and define a novel type of membrane microdomain. Annu. Rev. Cell Dev. Biol. 2003;19:397–422. 10.1146/annurev.cellbio.19.111301.153609 [DOI] [PubMed] [Google Scholar]

[ref17] 17. Li P, Kaslan M, Lee SH, et al. : Progress in exosome isolation techniques. Annu. Rev. Cell Dev. Biol. 2017a;19:397–422. 10.1146/annurev.cellbio.19.111301.153609 [DOI] [Google Scholar]

[ref18] 18. Hu Q, Su H, Li J, et al. : Clinical applications of exosome membrane proteins. Precis. Clin. Med. 2020 Mar;3(1):54–66. 10.1093/pcmedi/pbaa007 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref19] 19. Li L, Zhu D, Huang L, et al. : Argonaute 2 complexes selectively protect the circulating microRNAs in cell-secreted microvesicles. PLoS One. 2012;7(10):e46957. 10.1371/journal.pone.0046957 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref20] 20. Niel G, Porto-Carreiro I, Simoes S, et al. : Exosomes: a common pathway for a specialized function. J. Biochem. 2006 Jul;140(1):13–21. 10.1093/jb/mvj128 [DOI] [PubMed] [Google Scholar]

[ref21] 21. Gallo A, Alevizos I: Isolation of circulating microRNA in saliva. Methods Mol. Biol. 2013;1024:183–190. 10.1007/978-1-62703-453-1_14 [DOI] [PubMed] [Google Scholar]

[ref22] 22. Köberle V, Pleli T, Schmithals C, et al. : Differential stability of cell-free circulating microRNAs: implications for their utilization as biomarkers. PLoS One. 2013 Sep 20;8(9):e75184. 10.1371/journal.pone.0075184 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref23] 23. Record M, Carayon K, Poirot M, et al. : Exosomes as new vesicular lipid transporters involved in cell-cell communication and various pathophysiologies. Biochim. Biophys. Acta. 2014 Jan;1841(1):108–120. 10.1016/j.bbalip.2013.10.004 [DOI] [PubMed] [Google Scholar]

[ref24] 24. Li W, Han Y, Zhao Z, et al. : Oral mucosal mesenchymal stem cell-derived exosomes: A potential therapeutic target in oral premalignant lesions. Int. J. Oncol. 2019 May;54(5):1567–1578. 10.3892/ijo.2019.4756 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref25] 25. Wang L, Yin P, Wang J, et al. : Delivery of mesenchymal stem cells-derived extracellular vesicles with enriched miR-185 inhibits progression of OPMD. Artif Cells Nanomed Biotechnol. 2019 Dec;47(1):2481–2491. 10.1080/21691401.2019.1623232 [DOI] [PubMed] [Google Scholar]

[ref26] 26. Liu J, Li F, Liu B, et al. : Adipose-derived mesenchymal stem cell exosomes inhibit transforming growth factor-β1-induced collagen synthesis in oral mucosal fibroblasts. Exp. Ther. Med. 2021 Dec;22(6):1419. 10.3892/etm.2021.10854 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref27] 27. Zhou S, Zhu Y, Li Z, et al. : Exosome-derived long non-coding RNA ADAMTS9-AS2 suppresses progression of oral submucous fibrosis via AKT signalling pathway. J. Cell. Mol. Med. 2021 Feb;25(4):2262–2273. 10.1111/jcmm.16219 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref28] 28. Lodi G, Scully C, Carrozzo M, et al. : Current controversies in oral lichen planus: report of an international consensus meeting. Part 2. Clinical management and malignant transformation. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2005 Aug;100(2):164–178. 10.1016/j.tripleo.2004.06.07 [DOI] [PubMed] [Google Scholar]

[ref29] 29. Warnakulasuriya S, Johnson NW, Waal I: Nomenclature and classification of potentially malignant disorders of the oral mucosa. J. Oral Pathol. Med. 2007 Nov;36(10):575–580. 10.1111/j.1600-0714.2007.00582.x [DOI] [PubMed] [Google Scholar]

[ref30] 30. Byun JS, Hong SH, Choi JK, et al. : Diagnostic profiling of salivary exosomal microRNAs in oral lichen planus patients. Oral Dis. 2015 Nov;21(8):987–993. 10.1111/odi.12374 [DOI] [PubMed] [Google Scholar]

[ref31] 31. Zhu X, Qin X, Wang X, et al. : Oral cancer cell-derived exosomes modulate natural killer cell activity by regulating the receptors on these cells. Int. J. Mol. Med. 2020 Dec;46(6):2115–2125. 10.3892/ijmm.2020.4736 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref32] 32. Whitefield TL: Tumor- derived exosomes and their role in tumor-induced immune suppression. Vaccines. 2016;4:35. 10.3390/vaccines4040035 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref33] 33. Zhang HG, Grizzle WE: Exosomes: a novel pathway of local and distant intercellular communication that facilitates the growth and metastasis of neoplastic lesions. Am. J. Pathol. 2014 Jan;184(1):28–41. 10.1016/j.ajpath.2013.09.027 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref34] 34. Vered M, Lehtonen M, Hotakainen L, et al. : Caveolin-1 accumulation in the tongue cancer tumor microenvironment is significantly associated with poor prognosis: an in-vivo and in-vitro study. BMC Cancer. 2015 Jan 30;15:25. 10.1186/s12885-015-1030-6 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref35] 35. Dayan D, Salo T, Salo S, et al. : Molecular crosstalk between cancer cells and tumor microenvironment components suggests potential targets for new therapeutic approaches in mobile tongue cancer. Cancer Med. 2012 Oct;1(2):128–140. 10.1002/cam4.24 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref36] 36. Wang SH, Liou GG, Liu SH, et al. : Laminin γ2-enriched extracellular vesicles of oral squamous cell carcinoma cells enhance in vitro lymphangiogenesis via integrin α3-dependent uptake by lymphatic endothelial cells. Int. J. Cancer. 2019 Jun 1;144(11):2795–2810. 10.1002/ijc.32027 [DOI] [PubMed] [Google Scholar]

[ref37] 37. Theodoraki MN, Yerneni SS, Hoffmann TK, et al. : Clinical Significance of PD-L1 ⁺ Exosomes in Plasma of Head and Neck Cancer Patients. Clin. Cancer Res. 2018 Feb 15;24(4):896–905. 10.1158/1078-0432.CCR-17-2664.905 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref38] 38. Rabinowits G, Bowden M, Flores LM, et al. : Comparative Analysis of MicroRNA Expression among Benign and Malignant Tongue Tissue and Plasma of Patients with Tongue Cancer. Front. Oncol. 2017 Aug 29;7:191. 10.3389/fonc.2017.00191 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref39] 39. Sharma S, Gillespie BM, Palanisamy V, et al. : Quantitative nanostructural and single-molecule force spectroscopy biomolecular analysis of human-saliva-derived exosomes. Langmuir. 2011 Dec 6;27(23):14394–14400. 10.1021/la2038763 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref40] 40. Sakha S, Muramatsu T, Ueda K, et al. : Exosomal microRNA miR-1246 induces cell motility and invasion through the regulation of DENND2D in oral squamous cell carcinoma. Sci. Rep. 2016 Dec 8;6:38750. 10.1038/srep38750 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref41] 41. Kawakubo-Yasukochi T, Morioka M, Hazekawa M, et al. : miR-200c-3p spreads invasive capacity in human oral squamous cell carcinoma microenvironment. Mol. Carcinog. 2018 Feb;57(2):295–302. 10.1002/mc.2274 [DOI] [PubMed] [Google Scholar]

[ref42] 42. Qadir F, Aziz MA, Sari CP, et al. : Transcriptome reprogramming by cancer exosomes: identification of novel molecular targets in matrix and immune modulation. Mol. Cancer. 2018 Jul 16;17(1):97. 10.1186/s12943-018-0846-5 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref43] 43. Liu T, Chen G, Sun D, et al. : Exosomes containing miR-21 transfer the characteristic of cisplatin resistance by targeting PTEN and PDCD4 in oral squamous cell carcinoma. Acta Biochim. Biophys. Sin. Shanghai. 2017 Sep 1;49(9):808–816. 10.1093/abbs/gmx078 [DOI] [PubMed] [Google Scholar]

[ref44] 44. Langevin S, Kuhnell D, Parry T, et al. : Comprehensive microRNA-sequencing of exosomes derived from head and neck carcinoma cells in vitro reveals common secretion profiles and potential utility as salivary biomarkers. Oncotarget. 2017 Jul 27;8(47):82459–82474. 10.18632/oncotarget.19614 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref45] 45. He L, Ping F, Fan Z, et al. : Salivary exosomal miR-24-3p serves as a potential detective biomarker for oral squamous cell carcinoma screening. Biomed. Pharmacother. 2020 Jan;121:109553. 10.1016/j.biopha.2019.109553 [DOI] [PubMed] [Google Scholar]

[ref46] 46. Nonaka T, Wong DTW: Salivary exosomics in cancer. Molecular characterization of cancer-derived exosomes in saliva. Enzyme. 2017;42:125–151. 10.1016/bs.enz.2017.08.002 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref47] 47. Faur CI, Rotaru H, Osan C, et al. : Salivary exosomal microRNAs as biomarkers for head and neck cancer detection-a literature review. Maxillofac. Plast. Reconstr. Surg. 2021 Jun 30;43(1):19. 10.1186/s40902-021-00303-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref48] 48. Winck FV, Prado Ribeiro AC, Ramos Domingues R, et al. : Insights into immune responses in oral cancer through proteomic analysis of saliva and salivary extracellular vesicles. Sci. Rep. 2015;5:16305. 10.1038/srep16305 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref49] 49. Wang z, Li F, Rufo J, et al. : Acoustofluidic salivary exosome isolation a liquid biopsy compatible approach for human papillomavirus associated oropharyngeal cancer detaction. J. Mol. Diagn. 2020;22:50–59. 10.1016/j.jmoldx.2019.08.004 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref50] 50. Cai J, Qiao B, Gao N, et al. : Oral squamous cell carcinoma-derived exosomes promote M2 subtype macrophage polarization mediated by exosome-enclosed miR-29a-3p. Am. J. Physiol. Cell Physiol. 2019 May 1;316(5):C731–C740. 10.1152/ajpcell.00366.2018 [DOI] [PubMed] [Google Scholar]

[ref51] 51. Xiao M, Zhang J, Chen W, et al. : M1-like tumor-associated macrophages activated by exosome-transferred THBS1 promote malignant migration in oral squamous cell carcinoma. J. Exp. Clin. Cancer Res. 2018 Jul 9;37(1):143. 10.1186/s13046-018-0815-2 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref52] 52. Zhu X, Qin X, Wang X, et al. : Oral cancer cell-derived exosomes modulate natural killer cell activity by regulating the receptors on these cells. Int. J. Mol. Med. 2020 Dec;46(6):2115–2125. 10.3892/ijmm.2020.4736 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref53] 53. Wang Y, Qin X, Zhu X, et al. : Oral cancer-derived exosomal NAP1 enhances cytotoxicity of natural killer cells via the IRF-3 pathway. Oral Oncol. 2018 Jan;76:34–41. 10.1016/j.oraloncology.2017.11.024 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref54] 54. Huang SH, Li Y, Zhang J, et al. : Epidermal growth factor receptor-containing exosomes induce tumor-specific regulatory T cells. Cancer Investig. 2013 Jun;31(5):330–335. 10.3109/07357907.2013.789905 [DOI] [PubMed] [Google Scholar]

[ref55] 55. Fujiwara T, Eguchi T, Sogawa C, et al. : Carcinogenic epithelial-mesenchymal transition initiated by oral cancer exosomes is inhibited by anti-EGFR antibody cetuximab. Oral Oncol. 2018 Nov;86:251–257. 10.1016/j.oraloncology.2018.09.030 [DOI] [PubMed] [Google Scholar]

[ref56] 56. Fujiwara T, Eguchi T, Sogawa C, et al. : Anti-EGFR antibody cetuximab is secreted by oral squamous cell carcinoma and alters EGF-driven mesenchymal transition. Biochem. Biophys. Res. Commun. 2018 Sep 10;503(3):1267–1272. 10.1016/j.bbrc.2018.07.035 [DOI] [PubMed] [Google Scholar]

[ref57] 57. Ono K, Eguchi T, Sogawa C, et al. : HSP-enriched properties of extracellular vesicles involve survival of metastatic oral cancer cells. J. Cell. Biochem. 2018 Sep;119(9):7350–7362. 10.1002/jcb.27039 [DOI] [PubMed] [Google Scholar]

[ref58] 58. Sun LP, Xu K, Cui J, et al. : Cancer-associated fibroblast-derived exosomal miR-382-5p promotes the migration and invasion of oral squamous cell carcinoma. Oncol. Rep. 2019 Oct;42(4):1319–1328. 10.3892/or.2019.7255 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref59] 59. Languino LR, Singh A, Prisco M, et al. : Exosome-mediated transfer from the tumor microenvironment increases TGFβ signaling in squamous cell carcinoma. Am. J. Transl. Res. 2016 May 15;8(5):2432–2437. [PMC free article] [PubMed] [Google Scholar]

[ref60] 60. Yang WW, Yang LQ, Zhao F, et al. : Epiregulin Promotes Lung Metastasis of Salivary Adenoid Cystic Carcinoma. Theranostics. 2017 Aug 23;7(15):3700–3714. 10.7150/thno.19712 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref61] 61. Hou J, Wang F, Liu X, et al. : Tumor-derived exosomes enhance invasion and metastasis of salivary adenoid cystic carcinoma cells. J. Oral Pathol. Med. 2018 Feb;47(2):144–151. 10.1111/jop.12654 [DOI] [PubMed] [Google Scholar]

[ref62] 62. Ha D, Yang N, Nadithe V: Exosomes as therapeutic drug carriers and delivery vehicles across biological membranes: current perspectives and future challenges. Acta Pharm. Sin. B. 2016 Jul;6(4):287–296. 10.1016/j.apsb.2016.02.001 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref63] 63. Jiang XC, Gao JQ: Exosomes as novel bio-carriers for gene and drug delivery. Int. J. Pharm. 2017 Apr 15;521(1-2):167–175. 10.1016/j.ijpharm.2017.02.038 [DOI] [PubMed] [Google Scholar]

[ref64] 64. Balasaheb Mali S, Dahivelkar S: Liquid biopsy = Individualized cancer management: Diagnosis, monitoring treatment and checking recurrence and metastasis. Oral Oncol. 2021 Dec;123:105588. 10.1016/j.oraloncology.2021.105588 [DOI] [PubMed] [Google Scholar]

[ref65] 65. Principe S, Hui AB, Bruce J, et al. : Tumor-derived exosomes and microvesicles in head and neck cancer: implications for tumor biology and biomarker discovery. Proteomics. 2013 May;13(10-11):1608–1623. 10.1002/pmic.201200533 [DOI] [PubMed] [Google Scholar]

[ref66] 66. Liu H, Huang Y, Huang M, et al. : Current Status, Opportunities, and Challenges of Exosomes in Oral Cancer Diagnosis and Treatment. Int. J. Nanomedicine. 2022 Jun 16;17:2679–2705. 10.2147/IJN.S365594 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref67] 67. Sun D, Zhuang X, Xiang X, et al. : A novel nanoparticle drug delivery system: the anti-inflammatory activity of curcumin is enhanced when encapsulated in exosomes. Mol. Ther. 2010 Sep;18(9):1606–1614. 10.1038/mt.2010.105 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref68] 68. Pascucci L, Coccè V, Bonomi A, et al. : Paclitaxel is incorporated by mesenchymal stromal cells and released in exosomes that inhibit in vitro tumor growth: a new approach for drug delivery. J. Control. Release. 2014 Oct 28;192:262–270. 10.1016/j.jconrel.2014.07.042 [DOI] [PubMed] [Google Scholar]

[ref69] 69. Zeelenberg IS, Ostrowski M, Krumeich S, et al. : Targeting tumor antigens to secreted membrane vesicles in vivo induces efficient antitumor immune responses. Cancer Res. 2008 Feb 15;68(4):1228–1235. 10.1158/0008-5472.CAN-07-3163 [DOI] [PubMed] [Google Scholar]

[ref70] 70. Johnsen KB, Gudbergsson JM, Skov MN, et al. : Evaluation of electroporation-induced adverse effects on adipose-derived stem cell exosomes. Cytotechnology. 2016 Oct;68(5):2125–2138. 10.1007/s10616-016-9952-7 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref71] 71. Fuhrmann G, Serio A, Mazo M, et al. : Active loading into extracellular vesicles significantly improves the cellular uptake and photodynamic effect of porphyrins. J. Control. Release. 2015;205:35–44. 10.1016/j.jconrel.2014.11.029 [DOI] [PubMed] [Google Scholar]

[ref72] 72. Kim MS, Haney MJ, Zhao Y, et al. : Development of exosome-encapsulated paclitaxel to overcome MDR in cancer cells. Nanomedicine. 2016 Apr;12(3):655–664. 10.1016/j.nano.2015.10.012 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref73] 73. Sato YT, Umezaki K, Sawada S, et al. : Engineering hybrid exosomes by membrane fusion with liposomes. Sci. Rep. 2016 Feb 25;6:21933. 10.1038/srep21933 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref74] 74. Wu D, Kang L, Tian J, et al. : Exosomes Derived from Bone Mesenchymal Stem Cells with the Stimulation of Fe ₃O ₄ Nanoparticles and Static Magnetic Field Enhance Wound Healing Through Upregulated miR-21-5p. Int. J. Nanomedicine. 2020 Oct 19;15:7979–7993. 10.2147/IJN.S275650 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref75] 75. Chen Y, Hou S: Application of magnetic nanoparticles in cell therapy. Stem Cell Res. Ther. 2022;13:135. 10.1186/s13287-022-02808-0 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref76] 76. Maacha S, Bhat AA, Jimenez L, et al. : Extracellular vesicles-mediated intercellular communication: roles in the tumor microenvironment and anti-cancer drug resistance. Mol. Cancer. 2019 Mar 30;18(1):55. 10.1186/s12943-019-0965-7 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref77] 77. Kamerkar S, LeBleu VS, Sugimoto H, et al. : Exosomes facilitate therapeutic targeting of oncogenic KRAS in pancreatic cancer. Nature. 2017 Jun 22;546(7659):498–503. 10.1038/nature22341 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref78] 78. Cheng Q, Shi X, Han M, et al. : Reprogramming Exosomes as Nanoscale Controllers of Cellular Immunity. J. Am. Chem. Soc. 2018 Dec 5;140(48):16413–16417. 10.1021/jacs.8b10047 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref79] 79. Kalluri R, McAndrews KM: The role of extracellular vesicles in cancer. Cell. 2023 Apr 13;186(8):1610–1626. 10.1016/j.cell.2023.03.010 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref80] 80. Dooley K, McConnell RE, Xu K, et al. : A versatile platform for generating engineered extracellular vesicles with defined therapeutic properties. Mol. Ther. 2021 May 5;29(5):1729–1743. 10.1016/j.ymthe.2021.01.020.) [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref81] 81. Taylor DD, Shah S: Methods of isolating extracellular vesicles impact down-stream analyses of their cargoes. Methods. 2015 Oct 1;87:3–10. 10.1016/j.ymeth.2015.02.019 [DOI] [PubMed] [Google Scholar]

[ref82] 82. Butreddy A, Kommineni N, Dudhipala N: Exosomes as Naturally Occurring Vehicles for Delivery of Biopharmaceuticals: Insights from Drug Delivery to Clinical Perspectives. Nanomaterials (Basel). 2021 Jun 3;11(6):1481. 10.3390/nano11061481 [DOI] [PMC free article] [PubMed] [Google Scholar]

[ref83] 83. Stremersch S, De Smedt SC, Raemdonck K: Therapeutic and diagnostic, applications of extracellular vesicles. J. Control. Release. 2016;244:167–183. 10.1016/j.jconrel.2016.07.054 [DOI] [PubMed] [Google Scholar]

PERMALINK

Exosomes: Mediators of cellular communication in potentially malignant oral lesions and head and neck cancers

Monica Charlotte Solomon

Chetana Chandrashekar

Spoorti Kulkarni

Nisha Shetty

Aditi Pandey

Roles

Version Changes

Revised. Amendments from Version 1

Abstract

Introduction

Figure 1. Exosomes.

Characteristic features of exosomes

Transmission electron microscopy

Nanoparticle tracking analysis

Atomic force microscopy

Enzyme linked immunosorbent analysis (ELISA)

Western blot

Exosomes in oral potentially malignant disorders

Exosomes in oral submucous fibrosis

Exosomes in oral lichen planus

Exosomes in oral cancer

Figure 2. Role of exosomes in oral cancer.

Cancer associated fibroblasts

Exosomes in salivary gland malignancies

Table 1. Exosomal components in the biology of potentially malignant oral disorders.

Table 2. Exosomal components in the biology of head and neck Cancers.

Exosomes in oral cancer treatment – drug delivery

Challenges in the clinical application of exosomes

Conclusion

Data availability

Funding Statement

References

Reviewer response for version 2

Jiji George

Roles

Reviewer response for version 2

Ajaz A Bhat

Roles

Reviewer response for version 1

Ajaz A Bhat

Roles

References

Monica Charlotte Solomon

Reviewer response for version 1

John W Barrett

Roles

Monica Charlotte Solomon

Associated Data

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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