MiR-224-5p Targeting OCLN Promotes the Proliferation, Migration, and Invasion of Clear Cell Renal Cell Carcinoma Cells.

A number of studies reported that miR-224-5p is involved in a variety of cancer-related cellular processes, yet its physiological role in clear cell renal cell carcinoma (ccRCC) remains unclear. In order to clarify the function of miR-224-5p in ccRCC, real-time quantitative-PCR was conducted to compare the expression of miR-224-5p in human normal renal tubular epithelial cell lines and ccRCC cell lines first, and a strikingly upregulated expression was observed in ccRCC cell lines. Inhibition of miR-224-5p expression by microRNA inhibitors could inhibit the proliferation, migration, and invasion of ccRCC cells. Besides, it was validated by dual-luciferase assay in which miR-224-5p directly targeted OCLN gene. The expression of OCLN was downregulated in ccRCC cells, and overexpression of miR-224-5p could inhibit the mRNA and protein expression levels of OCLN. Overexpression of OCLN could reduce the proliferation, migration, and invasion of ccRCC cells, while overexpressed miR-224-5p could partially reverse that inhibitory effect. Therefore, the promotive effect of miR-224-5p on the proliferation, invasion, and migration of ccRCC cell lines was at least partly due to the inhibition of OCLN expression. These findings highlighted the important function of miR-224-5p, which was promoting cell proliferation, migration, and invasion by downregulating OCLN, in the pathogenesis of ccRCC, and provided a potential treatment strategy.

Exosomes Derived from Cancer-Associated Fibroblasts Regulate Cell Progression in Clear-Cell Renal-Cell Carcinoma.

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.