Table 1.
Summary of published work on the distinct role of CSC-derived exosomes in tumorigenicity.
| Exosome population | Tumorigenic action | Proposed mechanism of action | Reference |
|---|---|---|---|
| Macrovesicles derived from CD105+ cells of renal carcinoma specimens | Promoted angiogenesis and metastasis both in vitro and in vivo | miRNA screening showed 24 upregulated, and 33 downregulated miRNAs in CD105+ macrovesicles compared to CD105− macrovesicles. This distinct miRNA composition favor tumor growth and invasion. | (Grange et al., 2011) |
| Exosomes derived from CD133+ cells of glioblastoma cell line | Increased the in vitro angiogenic capacity of endothelial cells | miRNA analysis revealed elevated levels of miRNA-21 in the CD133+ cells, hypothesizing that the derived exosomes promoted angiogenesis through the miRNA-21/VEGF pathway. | (Sun et al., 2017) |
| Exosomes derived from CD105+ cells of clear cell renal cell carcinoma specimens | Induced EMT of cancer cells in vitro, and promoted metastasis in vivo | miRNA analysis revealed elevated levels of miRNA-19b-3p in the CD105+ cell-derived exosomes. This in turn affected the protein levels of PTEN, a key mediator of cell migration. | (Wang et al., 2019) |
| Exosomes derived from spheroid formations of thyroid cancer cell lines | Induced in vitro EMT in normal and non-cancerous thyroid cells | miRNA analysis revealed elevated levels of MALTA1, EMT marker SLUG and stem cell marker SOX2, in exosome treated cells. | (Hardin et al., 2018) |
| Exosomes derived from glioblastoma cell lines cells cultured in stem cell-permissive medium |
Polarized monocytes into M2 macrophage phenotype | Western Blot analysis revealed up regulation of PD-L1 in exosome-treated monocytes. PD-L1 correlates with increased STAT3 pathway phosphorylation, which mediate this immune suppressive switch. | (Gabrusiewicz et al., 2018) |
| Exosomes derived from spheroid formations of colorectal cancer cell line | Prompted a pro-tumoral phenotype in neutrophils | miRNA and ELISA analysis revealed elevated levels of IL-1β in exosome-treated neutrophils and their condition medium. | (Hwang et al., 2019) |
PTEN, phosphatase and tensin homolog; MALTA1, metastasis associated lung adenocarcinoma transcript 1; PD-l1, programmed death-ligand 1; ELISA, enzyme-linked immunosorbent assay.