A Preliminary Study of miR-144 Inhibiting the Stemness of Colon Cancer Stem Cells by Targeting Krüppel-Like Factor 4.

Abstract

Colon cancer is a prevalent clinical malignant tumor of the digestive system. The current study aims to explore the miR-144 expression in colorectal cancer (CRC) cell lines and CRC stem cells (CSCs) and to explore its effect on the stemness of CSCs and the targeted regulation of Krüppel-like factor 4 (KLF4). Use qRT-PCR to detect the expression level of miR-144 in CRC cells SW480, HCT116, and H129 and the healthy colon cell NCM460. The CSCs that were used were cultured in HCT116 cells. Use western blot to explore the expressions of Nanog, SOX2, and OCT4 stemness marker protein. After it was transfected with miR-144 mimics or KLF4 plasmid, use MTT to explore the cell viability of CSCs, use flow cytometry to evaluate apoptosis, and use transwell assay to evaluate the ability of invasive of CSCs. The targeting effect of miR-144 on the KLF4 gene was verified using TargetScan prediction and the double-luciferase reporter gene test. Use qRT-PCR to evaluate the role of miR-144 mimics on KLF4 mRNA expression in CSCs. The qRT-PCR results exhibited that the miR-144 expression in CRC cells was higher than that in the healthy colon cell line. The expressions of OCT4, Nanog, and SOX2 stem cell markers were up-regulated in CSCs, and the expression of miR144 increased in CSCs. The cell viability, apoptosis, and invasion of CSCs increased after miR-144 was transfected. The TargetScan prediction and double-luciferase reporter gene assay confirmed that miR-144 was targeted by KLF4, and the expression of KLF4 mRNA in the miR-144 mimics group reduced. Moreover, the overexpression of KLF4 could partially reverse the role of miR-144 mimics on CSCs. In summary, miR-144 was highly expressed in CRC cell lines and CSCs, and the overexpression of miR-144 in CSCs significantly promoted the proliferation of CSCs, inhibited its apoptosis, and promoted its invasion ability. In addition, its preliminary mechanism, possibly through negative regulation KLF4, promotes the stemness of CSCs, and miR-144 is likely to be a potential target for eliminating CSC from CRC treatment.