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. 2025 Aug 29;20:60. doi: 10.1186/s13027-025-00689-5

Porphyromonas gingivalis and Fusobacterium nucleatum synergistically strengthen the effect of promoting oral squamous cell carcinoma progression

Xiao Song 1, Jingfei Wang 1, Zhen Gu 1, Xinyi Qiu 1, Meng Yuan 1, Huiji Ke 1, Runzhi Deng 1,✉
PMCID: PMC12398151  PMID: 40883778

Abstract

Objective

To investigate the mechanism of action of Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) individually and synergistically on Cal-27 cells through transcriptome analyses to evaluate the mechanism evidence of periodontal pathogen involvement in oral squamous cell carcinoma.

Methods

Cal-27 cells were treated with P. gingivalis and F. nucleatum individually or in combination. Cell proliferation was assessed via CCK-8 assay and EdU staining, while migration was evaluated using scratch assays. Transcriptomic sequencing analyzed molecular mechanisms underlying single and co-infections.

Results

Synergistic treatment with P. gingivalis and F. nucleatum significantly enhanced Cal-27 cell proliferation and migration compared to either pathogen alone. Transcriptomics revealed that co-infection accelerated tumor cell cycle progression and amplified pro-inflammatory pathways, indicating stronger pro-tumorigenic effects.

Conclusion

This study clarifies the cooperative tumor-promoting role of multiple bacterial species, providing potential therapeutic targets for oral squamous cell carcinoma in bacterial infection contexts and highlighting the importance of controlling oral microbiota.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13027-025-00689-5.

Keywords: Porphyromonas gingivalis, Fusobacterium nucleatum, Cell cycle, Tumor proliferation, Oral squamous cell carcinoma

Introduction

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers in the oral and maxillofacial region, which leads patients to suffer from impaired appearance, swallowing, and taste [1]. The 5-year survival rates for individuals with OSCC remain below 50%. Persistent exposure to risk factors such as tobacco, alcohol, betel quid (BQ), and human papillomavirus (HPV) increases the incidence of OSCC [2]. Notably, studies have demonstrated that oral microbiota dysbiosis may serve as a clinical high-risk factor for OSCC [3, 4]. Understanding the association between oral microbiota and OSCC is crucial for both prevention and prognosis improvement [5, 6].

In 1998, Nagy first reported an increased abundance of the Porphyromonas and Fusobacterium genera within the oral microbiota of OSCC patients [7]. Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) are commensal microorganisms within the human oral cavity [8]. They colonize in the dorsal/ventral sides of the tongue, floor of the mouth, gingival sulci, and buccal mucosa, which are described to be primary lesion sites during OSCC initial presentation [9]. P. gingivalis promotes OSCC progression primarily by enhancing tumor cell proliferation and migration, while enabling tumor cells to evade host immune surveillance [10]. P. gingivalis accelerates the tumor cell progression through the S-phase of the cell cycle by modulation of cyclin/cyclin-dependent kinase activity and downregulation of the level of the p53 tumor suppressor protein [11]. Additionally, P. gingivalis-induced inflammation disrupts the immune homeostasis, thereby accelerating the proliferation of tumor cells [12]. F. nucleatum is a bridging bacterium that acts in a supportive role by co-aggregating bacterial colonization and helps form a stable biofilm structure [13]. High abundance of F. nucleatum could be consistently detected in both tumor tissues and saliva samples from OSCC patients [14–16]. Harrandah et al. [17] showed that compared to uninfected controls, F. nucleatum-colonized mice developed larger tumor volumes and higher tumor counts in the oral cavity. In addition to activating tumor cell proliferation [18], inducing inflammation [19], and promoting cell migration [20], F. nucleatum has also been demonstrated to enhance co-aggregation and colonization of other bacteria through its outer membrane adhesin Fap2 [21], thereby indirectly elevating the risk of OSCC development [22].

The pathogenesis of OSCC is generally conceptualized as highly complex, while accumulating evidence collectively highlights the occurrence of inter-microbial interactions within the oral microbiome [5, 23]. P. gingivalis and F. nucleatum exhibit a highly intricate interconnection. The colonization and reproduction of P. gingivalis require F. nucleatum [24], and F. nucleatum can enhance the invasion of human gingival epithelial cells by P. gingivalis [25], increasing the transmission of P. gingivalis to other body sites [26]. In addition, the diffusible signaling molecules of P. gingivalis enhance the metabolism of F. nucleatum by regulating gene expression, which in turn accelerates biofilm formation of P. gingivalis and F. nucleatum [27]. Studies have shown that when co-infected with P. gingivalis and F. nucleatum, the alveolar bone destruction would be more severe and expression levels of inflammatory mediators increased more significantly compared to individual infection [28–30].

Although numerous studies have confirmed that P. gingivalis and F. nucleatum individually promote the initiation and progression of OSCC [31] and synergistically accelerate the inflammation, there is insufficient experimental evidence demonstrating the synergistic or antagonistic interactions between P. gingivalis and F. nucleatum in contributing to OSCC [32]. In this study, to provide a theoretical basis for the effect of oral microbiome on OSCC development, we applied live bacteria directly to Cal-27 cells to simulate the living environment of tumor cells in the oral cavity, and analyzed the difference between the individual effect and the synergistic effect of P. gingivalis and F. nucleatum. This study holds promise for laying the preclinical groundwork to inform disease management strategies for OSCC.

Materials and methods

P. gingivalis and F. nucleatum culture

P. gingivalis (ATCC 33277) and F. nucleatum (ATCC 10953) species were obtained from the American Type Culture Collection (ATCC, Manassas, VA, USA). P. gingivalis and F. nucleatum were cultivated in blood agar plates. The brain heart infusion broth (BHI) (Hopebio, China) was supplemented with 0.5 g/L L-cysteine hydrochloride (Sigma Aldrich, USA), 5 g/L yeast extract (Sigma, USA), 2 mg/L vitamin K1 (Hopebio, China) and 5 mg/L hemin (Hopebio, China). For establishing a comparable biomass of the mixed strain, P. gingivalis and F. nucleatum were mixed according to the ratio of 100:1, and the mixed strain was obtained after culture for 24 h. The inoculum concentration of each species was adjusted to 108 CFU/mL based on the standard curve of OD600nm vs. CFU/mL.

Cell culture and treatment

OSCC cell line of Cal-27 was cultured in MEM (Gibco, USA) containing 10% FBS (Excell, USA) in an incubator with 5% CO2 at 37 °C. Cal-27 cells were infected by P. gingivalis and F. nucleatum individually and collaboratively, and then washed three times with PBS (Hyclone, USA).

CCK-8 assay

Cal-27 cells were seeded in a 96-well plate at a density of 4.0 × 103 cells/well. Then, with or without P. gingivalis and F. nucleatum at different MOI (25:1, 50:1 and 100:1), after incubation for 1, 2, and 3 days, medium without FBS containing 10% of CCK-8 solution (Dojindo, Shanghai, China) was added to each well for 1 h treatment at 37 °C. The absorbance at 450 nm was examined by a SpectraMax M3 microplate reader.

EdU detection

Cells were seeded in a 6-well plate at a density of 4.0 × 105 cells/well. After being infected by P. gingivalis, F. nucleatum and mixed species (MOI:25:1) for 12 h, Cal-27 cells were treated with 10 µM 5-ethynyl-2’ -deoxyuridine (EdU) working solution in 2 h. Then cells were fixed with 4% paraformaldehyde for 20 min, and permeabilized by PBS with 0.3%Triton X-100. BeyoClick™ EdU Cell Proliferation Kit (Beyotime, China) was used to detect the EdU in Cal-27 cells. The fluorescence intensity was observed by the confocal fluorescence microscope at 562 nm recorded by the FACS Calibur system.

Scratch assay

Cells were seeded in a 6-well plate at a density of 4.0 × 105 cells/well. After being infected by P. gingivalis, F. nucleatum and mixed species (MOI:25:1), operator scratched on the bottom of each well. Then the scratches were observed after 0, 6, and 12 h with the optical microscope.

Transcriptome analyses

After treated with P. gingivalis, F. nucleatum and mixed species (MOI:25:1) for 6 h, Cal-27 cells were collected and the total RNA was extracted from the tissue using TRIzol® Reagent according the manufacturer’s instructions. Then RNA quality was determined by 5300 Bioanalyser (Agilent) and quantified using the ND-2000 (NanoDrop Technologies). Only high-quality RNA sample (OD260/280 = 1.8 ~ 2.2, OD260/230 ≥ 2.0, RIN ≥ 6.5, 28 S:18 S ≥ 1.0, >1 µg) was used to construct sequencing library.

RNA purification, reverse transcription, library construction and sequencing were performed at Hangzhou cosmos wisdom Biotechnology Co., Ltd. (Hangzhou, China) according to the manufacturer’s instructions (Illumina, San Diego, CA). The RNA-seq transcriptome librariy was prepared following Illumina® Stranded mRNA Prep, Ligation from Illumina (San Diego, CA) using 1 µg of total RNA. Shortly, messenger RNA was isolated according to polyA selection method by oligo (dT) beads and then fragmented by fragmentation buffer firstly. Secondly double-stranded cDNA was synthesized using a SuperScript double-stranded cDNA synthesis kit (Invitrogen, CA) with random hexamer primers (Illumina). Then the synthesized cDNA was subjected to end-repair, phosphorylation and ‘A’ base addition according to Illumina’s library construction protocol. Libraries were size selected for cDNA target fragments of 300 bp on 2% Low Range Ultra Agarose followed by PCR amplified using Phusion DNA polymerase (NEB) for 15 PCR cycles. After quantified by Qubit 4.0, paired-end RNA-seq sequencing library was sequenced with the NovaSeq 6000 sequencer (2 × 150 bp read length).

The raw paired end reads were trimmed and quality controlled by fastp with default parameters. Then clean reads were separately aligned to reference genome with orientation mode using HISAT2 software. The mapped reads of each sample were assembled by StringTie in a reference-based approach.

To identify DEGs (differential expression genes) between two different samples, the expression level of each transcript was calculated according to the transcripts per million reads (TPM) method. RSEM was used to quantify gene abundances. Essentially, differential expression analysis was performed using the DESeq2 or DEGseq. DEGs with |log2FC|≧1 and FDR ≤ 0.05 (DESeq2) or FDR ≤ 0.001 (DEGseq) were considered to be significantly different expressed genes. In addition, functional-enrichment analysis including GO and KEGG were performed to identify which DEGs were significantly enriched in GO terms and metabolic pathways at Bonferroni-corrected P-value ≤ 0.05 compared with the whole-transcriptome background. GO functional enrichment and KEGG pathway analysis were carried out by Goatools and KOBAS, respectively.

All the alternative splice events that occurred in our sample were identified by using recently releases program rMATS. Only the isoforms that were similar to the reference or comprised novel splice junctions were considered, and the splicing differences were detected as exon inclusion, exclusion, alternative 5′, 3′, and intron retention events.

Statistical analysis

Statistical analysis was conducted by GraphPad Prism 10.1 using the one-way analysis of variance. Numerical data are expressed as the mean ± SD. P < 0.05 was considered statistically significant.

Results

P. gingivalis and F. nucleatum promoted the proliferation of Cal-27 cells

Abnormal cell proliferation is one of the most prominent characteristics of tumors. To evaluate the effect of periodontal pathogens on the proliferation of C27 cells, live bacteria were added to cell culture medium at different MOI ratios, and cell proliferation was observed by CCK8 method. According to the results, bacteria significantly promoted cell proliferation at MOI ratios of 25:1 and 50:1, with the combined treatment of P. gingivalis and F. nucleatum showing a more pronounced proliferative effect. However, when the MOI ratio increased to 100:1, bacterial infection inhibited tumor cell proliferation (Fig. 1). In the subsequent experiments, the cells were infected by live bacteria at an MOI of 50:1.

Fig. 1.

Fig. 1

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Cell proliferation of Cal-27 cells treated with P. gingivalis and F. nucleatum at different MOI. * means P < 0.05, ** means P < 0.01, *** means P < 0.001, ns means P > 0.05

P. gingivalis and F. nucleatum synergistically promoted DNA synthesis of Cal-27 cells

EdU, a thymidine nucleoside analog, substitutes for thymine (T) to infiltrate the replicating DNA molecule during cell proliferation. This allows quantification of DNA synthesis as a direct measure of cellular proliferative capacity. In the current study, compared to the control group, both P. gingivalis and F. nucleatum treatment groups exhibited increased EdU fluorescence intensity, with P. gingivalis demonstrating a significantly higher signal than F. nucleatum. The highest EdU fluorescence intensity was observed in the P. gingivalis & F. nucleatum group, indicating that the synergistic treatment significantly accelerated the DNA synthesis rate of Cal-27 cells (Fig. 2).

Fig. 2.

Fig. 2

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The fluorescence intensity of EdU in Cal-27 cells treated with P. gingivalis and F. nucleatum at MOI 50:1. (A) The images of EdU staining. (B) Mean fluorescence intensity (MFI) of EdU detected by flow cytometry. Scale bar: 20 μm. * means P < 0.05, ** means P < 0.01, *** means P < 0.001, ns means P > 0.05

P. gingivalis and F. nucleatum synergistically promoted the migration of Cal-27 cells

One of the characteristics of OSCC is that there is a high rate of lymph node metastasis and systemic metastasis, and the 5-year survival rate of OSCC patients with lymph node metastasis is greatly reduced. Therefore, the factors that promote tumor cell migration deserve attention. The scratch assay was used to assess the effect of bacteria on tumor cell migration. Cell migration of Cal-27 was observed at two time points (6 and 12 h post-bacterial treatment), and wound healing rates were calculated. We found that both P. gingivalis and F. nucleatum promoted cell migration, however, P. gingivalis and F. nucleatum synergistically demonstrated stronger pro-proliferative effects at both 6 h and 12 h time points (Fig. 3).

Fig. 3.

Fig. 3

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The cell migration assay of Cal-27 cells treated with P. gingivalis and F. nucleatum at MOI 50:1. (A) The images of cell migration. (B) The relative wound healing area. Scale bar: 200 μm. * means P < 0.05, ** means P < 0.01, *** means P < 0.001, ns means P > 0.05

P. gingivalis and F. nucleatum synergistically positively regulated the proliferation and adhesion Cal-27 cells

477 up-regulated genes and 393 down-regulated genes were analyzed in the P. gingivalis & F. nucleatum group compared with the Control group (Fig. S1). GO enrichment analysis demonstrated that Cal-27 cells exhibited specific responses to lipopolysaccharides and other bacterial virulence factors, confirming bacterial stimulation. Notably, P. gingivalis and F. nucleatum exhibited synergistic effects in upregulating epithelial cell proliferation and cell adhesion, providing crucial evidence for their role in promoting tumor cell proliferation. In addition, the positive regulation of the MAPK cascade was enriched, which has been proven to be highly involved in the proliferation and differentiation of tumor cells. Furthermore, significant enrichment was observed in positive regulation of the MAPK cascade, a critical signaling pathway in tumor cell proliferation. The downstream ERK and JNK pathways of MAPK signaling were found to substantially drive tumor cell proliferation and differentiation through facilitation of G1/S phase transition and response to growth factors. GSEA Reactome analysis further demonstrated significant enrichment in “Assembly of the ORC complex at the origin of replication”. The ORC complex, being a core component for DNA replication initiation, plays a central regulatory role in cell cycle progression, particularly in the G1/S phase transition. Its upregulation directly indicates the initiation of S-phase cell replication and accelerated cellular proliferation (Fig. 4).

Fig. 4.

Fig. 4

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The RNA-seq analysis of Cal-27 cells. The GO, KEGG and GSEA enriched bubble diagram of up-regulated signaling pathway (P. gingivalis & F. nucleatum vs. Control)

Synergistic treatment amplificated the advantages in promoting tumor progression compared to separate treatment

We further investigated the distinct contributions of P. gingivalis and F. nucleatum to tumor progression and compared the effects of combined treatment with those of individual monotherapies. According to the GO enrichment results, P. gingivalis primarily enhanced cytokine production and promoted cytokine-mediated signaling pathways, while F. nucleatum predominantly strengthened chemokine responses and activated the MAPK signaling cascade. P. gingivalis and F. nucleatum were found to facilitate interactions between cytokines and their corresponding receptors. Notably, P. gingivalis significantly upregulated the NF-κB pathways, indicating its potential to indirectly drive tumor cell proliferation through the activation of inflammatory signaling pathways. In contrast, F. nucleatum exhibited a more pronounced role in positively regulating the IL-17 signaling pathway (Fig. S2).

101 up-regulated genes and 77 down-regulated genes were analyzed compared P. gingivalis group with the P. gingivalis & F. nucleatum group; 334 up-regulated genes and 440 down-regulated genes were analyzed in the F. nucleatum group compared with the P. gingivalis & F. nucleatum group (Fig. S3). Compared with the P. gingivalis group, the P. gingivalis & F. nucleatum group significantly upregulated pathways related to “regulation of DNA-binding transcription factor activity”. In contrast to the F. nucleatum group, the P. gingivalis & F. nucleatum group showed notable enrichment in “regulation of epithelial proliferation,” and enhanced cell adhesion and inflammatory responses in Cal-27 cells, including the upregulation of the NF-κB pathway, a key inflammation-related signaling cascade (Fig. 5).

Fig. 5.

Fig. 5

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The RNA-seq analysis of Cal-27 cells. The GO and KEGG enriched bubble diagram of up-regulated signaling pathway (P. gingivalis & F. nucleatum vs. P. gingivalis, P. gingivalis & F. nucleatum vs. F. nucleatum)

In summary, P. gingivalis primarily contributes to tumor cell adhesion and amplifies the inflammatory response through NF-κB activation, indirectly promoting tumor cell proliferation. In contrast, F. nucleatum is more closely associated with the MAPK signaling cascade and IL-17 pathway, driving tumor cell proliferation and migration by enhancing the expression of DNA transcription factors and chemokines within tumor cells.

Synergistic treatment of P. gingivalis and F. nucleatum significantly upregulated the cell cycle-related signaling pathways

Based on our previous transcriptome analysis, we identified that the proliferation-promoting mechanisms of P. gingivalis and F. nucleatum in Cal-27 cells primarily involve the regulation of cell cycle progression and inflammatory signaling pathways. To further elucidate the specific mechanisms underlying their tumor-promoting effects, we performed targeted enrichment analysis of pathways related to the cell cycle and inflammatory signaling. As shown in Fig. 6, the significant enrichment of the Wnt signaling pathway was observed, which is known to drive abnormal tumor cell proliferation and malignant progression by regulating cell cycle progression, maintaining stem cell characteristics, inducing epithelial-mesenchymal transition (EMT), and remodeling the tumor microenvironment. Additionally, pathways related to the cell cycle (particularly the G1/S phase transition) and serine/threonine kinase signaling were significantly enriched, suggesting accelerated cell cycle progression (Fig. 6A). KEGG pathway analysis further confirmed notable enrichment of the cell cycle pathway (Fig. 6B). Moreover, upregulation of the Hippo signaling pathway was detected, which is frequently associated with tumor cell proliferation through overactivation of its downstream effectors YAP/TAZ. In summary, our findings indicate that the synergistic tumor-promoting effects of P. gingivalis and F. nucleatum are primarily mediated by accelerating cell cycle progression, particularly the G1/S phase transition.

Fig. 6.

Fig. 6

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The RNA-seq analysis of Cal-27 cells. The GO and KEGG enriched bubble diagram of up-regulated signaling pathway (P. gingivalis & F. nucleatum vs. Control)

Discussion

OSCC is an invasive tumor with a high rate of metastasis and recurrence, which has primarily been shown to be related to the oral microbiome [33]. The oral microbiome exhibits the second highest level of individual diversity, following that of the gut [34], participating in the development of OSCC by promoting the proliferation, migration, and invasion of tumor cells [35]. Several studies compared the oral flora composition of cancer patients and normal subjects by 16 S rRNA amplicon sequencing, and found that periodontal pathogens were positively associated with OSCC [36, 37], especially P. gingivalis and F. nucleatum [6, 38]. However, tumor development is a combination of multiple factors; it is necessary to explore how P. gingivalis and F. nucleatum synergistically participate in OSCC.

In this study, we found that P. gingivalis and F. nucleatum could promote the proliferation and accelerate the migration of tumor cells with different mechanisms. P. gingivalis treatment significantly activated the response to lipopolysaccharide (LPS) and the bacterial original molecule, and the positively up-regulated cell adhesion was observed. Studies have shown that LPS did not alter migration, proliferation, or cell morphology, but it increased the ability to invade [39, 40]. In addition, P. gingivalis upregulated the toll-like receptor pathway that recognizes lipopolysaccharide and the downstream NF-κB pathway. The Toll/MyD88-NFκB axis has been proven to be associated with the high aggressiveness of OSCC [41]. Therefore, we confirm that P. gingivalis enhances tumor aggressiveness by promoting cell adhesion, mainly LPS-mediated. The up-regulation of the JAK/STAT signaling pathway also attracted our attention. The JAK/STAT signaling pathway activation can be triggered directly by P. gingivalis or by some inflammatory factors produced by cells after P. gingivalis stimulation, such as IL-1β, IL-6, and TNF-α [42–44]. JAK/STAT signaling pathway is involved in almost all cancer hallmark features, including tumor proliferation, metastasis, angiogenesis, immunosuppression, and tumor inflammation [45].

Notably, we found significant upregulation of IL-17 signaling pathways in the F. nucleatum group, which has rarely been reported. As an inflammatory cytokine, IL-17 contributes to the establishment of tumor stroma that supports tumor formation and growth, especially detected at the front of the tumor invasion [46, 47]. IL-17 mobilizes the production of inflammatory mediators and chemokines to trigger the inflammatory response and then to carcinogenic effects [48]. After treatment with F. nucleatum, we observed a significant upregulation of cellular chemotaxis, which may be related to upregulation of IL-17 [15, 22].

In the oral microbial ecology, the bacteria communicate and depend on each other, and the pathogenic unit is not formed by a single species [49]. P. gingivalis acts as a community activist that contributes to the dysbiotic process [50]. Gallimidi et al. suggested that exposure to P. gingivalis/F. nucleatum triggers TLR signaling, resulting in IL-6 production that activates STAT3, which induces important effectors driving oral cavity SCC growth and invasiveness [51]. According to the above results, the synergistic treatment of P. gingivalis and F. nucleatum seems to combine the advantages of separate treatments, resulting in more significant cell proliferation and migration in vitro. In addition, it has been reported that some bacterial species, such as Streptococcus gordonii (S. gordonii), could antagonize the tumor-promoting effect of P. gingivalis [52]. Therefore, when discussing the prevention and treatment of OSCC in terms of microbiome control, we must focus on the balance of the microbiome rather than the elimination of pathogenic bacteria.

In our study, the combined treatment of P. gingivalis and F. nucleatum appears to synergistically integrate the tumor-promoting “advantages” of single-species treatments. The tumorigenic effects of the combined treatment are primarily manifested in two ways: directly accelerating the cell cycle and indirectly promoting tumor proliferation by activating inflammatory signaling pathways to establish a chronic inflammatory microenvironment [53]. We highlight key molecular players that may serve as actionable targets for mitigating the tumor-promoting effects of bacterial infections. (1) ORC Complex. During the G1 phase of the cell cycle, the ORC complex binds to DNA replication origins and recruits other replication-associated proteins (such as CDC6 and the MCM complex) to form the pre-replication complex (pre-RC), which is essential for initiating DNA replication in the S phase [54]. By precisely controlling DNA replication initiation, the ORC complex ensures genomic stability. Its function is tightly regulated by mechanisms such as CDK activity and cell cycle checkpoint pathways. Dysregulation of the ORC complex can directly disrupt cell cycle progression, making it a potential therapeutic target for inhibiting tumor growth [55]. (2) Wnt Signaling Pathway. The Wnt signaling pathway plays a central role in regulating embryonic development, cell fate determination, and tissue homeostasis [56, 57]. The canonical Wnt/β-catenin pathway promotes G1/S phase transition and activates DNA replication-related genes thereby driving tumor cell proliferation [58]. Additionally, Wnt signaling maintains the self-renewal capacity of cancer stem cells (CSCs). Its interaction with the MAPK and NF-κB signaling pathways creates a vicious cycle of inflammation and proliferation, further exacerbating tumor progression [59]. (3) MAPK Inflammatory Signaling Cascade. Inflammation is a critical driver of tumor proliferation. The MAPK signaling cascade, activated by bacterial components via the TLR pathway, not only directly accelerates the cell cycle but also establishes a chronic inflammatory microenvironment conducive to tumor growth [60, 61].

In conclusion, our work elucidated the mechanism of promoting OSCC by P. gingivalis and F. nucleatum. P. gingivalis-derived lipopolysaccharide promoted the adhesion of tumor cells through the TLR/NF-κB axis and the JAK-STAT pathway, and F. nucleatum enhanced the chemotactic ability of tumor cells through activation of the IL-17 signaling pathway. Secondly, this study showed that P. gingivalis and F. nucleatum synergistic treatment integrated the above mechanisms and enhanced the tumor-promoting effects of individual treatments by accelerating the cell cycle and activating inflammatory MAPK signaling cascades (Fig. 7). These findings provide mechanistic insights into the cooperative role of periodontal pathogens in OSCC and highlight potential therapeutic targets.

Fig. 7.

Fig. 7

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An illustration of P. gingivalis and F. nucleatum synergistically effect on promoting tumor progression

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary Material 1 (43MB, docx)

Acknowledgements

This study was supported by the Project of the Nanjing Medical Science and Technique Development Foundation (YKK21183).

Author contributions

X.S. performed the in vitro experiments, the RNA-seq analyses and drafted the manuscript. J.W. and Z.G. contributed to conception, data acquisition, and critically revised the manuscript; X.Q. performed statistical analyses and critically revised the manuscript. M.Y. and H.K. contributed to data acquisition and interpretation. R.D. contributed to conception and design, provided the funding support and carefully revised the manuscript. All authors approved the final version of the manuscript.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Associated Data

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

Supplementary Materials

Supplementary Material 1 (43MB, docx)

Data Availability Statement

No datasets were generated or analysed during the current study.

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