A Novel miR-4745-KLC2 Axis Regulates Cancer Stem Cell Traits in Colorectal Cancer

Advanced colorectal cancer (CRC) treatments often fail due to chemoresistance and tumor recurrence, primarily driven by cancer stem cells (CSCs), which play a significant role in therapy ineffectiveness. MicroRNAs (miRNAs) play a pivotal role in regulating numerous biological functions within CSCs. Through a gain-of-function miRNA screening, we identified miRNAs that regulate the ALDEFLUOR-positive CSC population in colon cancer, with miR-4745 emerging as a promising inhibitor. Overexpression of miR-4745 reduced CSC self-renewal, diminished chemoresistance, and prevented CSC enrichment after chemotherapy in patient-derived CRC models. Mechanistically, miR-4745 directly targets the 3UTR of kinesin-light chain 2 (KLC2) mRNA, a member of the kinesin superfamily associated with poor clinical outcomes across various cancers. siRNA-mediated KLC2 downregulation reduced ALDH-positive CSCs and suppressed sphere formation, while KLC2 overexpression promoted CSC traits. Additionally, we observed an inverse correlation between KLC2 and miR-4745 mRNA levels in different colon cancer cell culture settings. Notably, KLC2 mRNA levels increased with local CRC progression and were correlated with poor overall survival in a cohort of over 1 000 stage I to IV colorectal cancer patients. Our study uncovers a novel miR-4745-KLC2 axis that regulates CSC properties and chemoresistance in CRC, offering a promising strategy to prevent relapse and improve clinical outcomes for patients.