MicroRNA Associated with the Invasive Phenotype in Clear Cell Renal Cell Carcinoma: Let-7c-5p Inhibits Proliferation,...

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Differential microRNA (miRNA) expression is implicated in clear cell renal cell carcinoma (ccRCC) progression.
• Previous research identified dysregulated miRNAs in early-stage ccRCC associated with aggressive phenotypes.

Purpose of the Study:

• To investigate miRNA expression differences between pathologic stage I (pT1) and upstaged pathologic stage 3 (pT3) ccRCC tumors.
• To assess the functional role of let-7c-5p and its target, insulin-like growth factor 1 receptor (IGF1R), in ccRCC aggressiveness.

Main Methods:

• Screening of miRNA expression in 20 clinical stage I (cT1) ccRCC tumors (10 pT1, 10 pT3).
• In vitro assays using ccRCC cell lines (786-O, Caki-1) to evaluate the effects of let-7c-5p transfection on cell proliferation, migration, and invasion.
• Assessment of IGF1R expression and its interaction with let-7c-5p using Simple Western and luciferase reporter assays.

Main Results:

• Twenty dysregulated miRNAs, including let-7c-5p, were identified between pT1 and pT3 ccRCC tumors.
• let-7c-5p was found to be downregulated in aggressive ccRCC.
• Overexpression of let-7c-5p in ccRCC cells significantly reduced proliferation, migration, invasion, and IGF1R expression.

Conclusions:

• miRNA dysregulation, particularly the downregulation of let-7c-5p, contributes to the progression and aggressiveness of small ccRCC tumors.
• let-7c-5p exerts its tumor-suppressive effects, at least in part, by regulating IGF1R expression and downstream signaling pathways involved in invasion.