miR-195-5p Suppresses KRT80 Expression Inducing Cell Cycle Arrest in Colon Cancer.

BACKGROUND/OBJECTIVES: Keratins form a crucial component of the epithelial cytoskeleton, playing an essential role in maintaining tissue architecture and coordinating key cellular functions. KRT80 is a type II keratin that has emerged as an oncogenic driver in several malignancies, yet its involvement in colorectal cancer (CRC) remains unclear. Here, we investigated the molecular interaction between miR-195-5p, KRT80 expression, and CRC growth. METHODS: Potential miR-195-5p binding sites in the KRT80 3'-UTR were identified through the use of integrated bioinformatic analyses, while publicly available datasets confirmed a significant overexpression of KRT80 in CRC tissues compared to normal mucosa. This finding was further validated through the use of mRNA and protein analysis in paired tumor and adjacent normal samples from CRC patients. RESULTS: Functional assays involving CRC cell lines showed that transfection with miR-195-5p mimics led to a significant downregulation of KRT80 expression, reflecting the effects of direct KRT80 silencing by siRNA. Both molecular approaches induced G(1)-phase cell cycle arrest, concomitantly with reductions in G(2)/M populations. Furthermore, the in vivo delivery of miR-195-5p mimics in a mouse model of colitis-associated CRC resulted in a significant reduction in Krt80 expression in the colon. CONCLUSIONS: Collectively, our results reveal that miR-195-5p negatively regulates KRT80 expression, contributing to its tumor-suppressive activity in colorectal cancer and highlighting a molecular mechanism with potential therapeutic relevance.