miR-6883 family miRNAs target CDK4/6 to induce G1 phase cell cycle arrest in colon cancer cells

CDK4/6 targeting is a promising therapeutic strategy under development for various tumor types. In this study, we used computational methods and TCGA dataset analysis to identify novel miRNAs that target CDK4/6 and exhibit potential for therapeutic development in colorectal cancer (CRC). The 3′UTR of CDK4/6 mRNAs are targeted by a family of miRNAs which includes miR-6883-5p, miR-149*, miR-6785-5p and miR-4728-5p. Ectopic expression of miR-6883-5p or miR-149* downregulated CDK4 and CDK6 levels in human CRC cells. RNA-seq analysis revealed an inverse relationship between the expression of CDK4/6 and miR-149* and intronic miRNA-6883-5p encoding the clock gene PER1 in CRC patient samples. Restoring expression of miR-6883-5p and miR-149* blocked cell growth leading to G0/G1 phase cell cycle arrest and apoptosis in CRC cells. CDK4/6 targeting by miR-6883-5p and miR-149* could only partially explain the observed anti-proliferative effects. Notably, both miRNAs synergized with the frontline CRC chemotherapy drug irinotecan. Further, they re-sensitized mutant p53-expressing cell lines resistant to 5-fluorouracil. Taken together, our results established the foundations of a candidate miRNA-based theranostic strategy to improve CRC management.

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