Abstract

Backgrounds: Exosomes from multiple sources function as regulatory factors in progression of various tumors. However, studies on the impact of exosomes from cancer-associated fibroblasts (CAFs) on tumor-cell proliferation, migration, invasion, and cycle regulation in clear-cell renal-cell carcinoma (ccRCC) are still lacking. Methods: A Western blot assay was performed to test the exosome-related marker protein level in exosomes derived from CAFs and normal fibroblasts (NFs). A confocal microscope was utilized to observe the internalization of CAF- and NF-derived exosomes after coculturing with cancer cells. MTT, EdU, colony formation, and transwell assays were conducted to detect progression of cancer cells incubated with CAF-derived exosomes. A Western blot assay was also conducted to test expression levels of metastasis-associated proteins. Changes in cell apoptosis and cell cycle were measured by flow cytometry. Results: Expression of CAF-derived exosome-related marker proteins was higher than that from NFs. Exosomes derived from CAFs and NFs could enter into cancer cells smoothly and be internalized by cancer cells. After cancer cells were cocultured with CAF-derived exosomes, cell proliferation, migration, and invasion were notably enhanced, and cell apoptosis was reduced. Moreover, expression of fibronectin, N-cadherin, vimentin, MMP9, and MMP2 in cancer cells increased, while E-cadherin was decreased. Besides, the proportion of cancer cells in the S phase increased. Conclusion: CAF-derived exosomes are internalized into ccRCC cells and promote the progression of ccRCC.