MiR-381 Reverses Multidrug Resistance by Negative Regulation of the CTNNB1/ABCB1 Pathway in HepG2/Dox Cells, and the Diagnostic and Prognostic Values of CTNNB1/ABCB1 Are Identified in Patients with LIHC.

Abstract

Multidrug resistance (MDR) is the biggest challenge in cancer therapy. In this study, we explored the molecular mechanism of MDR in human liver cancer and explored the related diagnostic and prognostic values of the targeted genes in patients with hepatocellular carcinoma. We constructed a multidrug-resistant liver cancer cell line, HepG2/Dox, using the parental subline HepG2. The (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay was used to test the viability of the liver cancer cells. Western blotting was performed to test the expression of ABCB1, β-catenin, and β-actin. Luciferase assays were performed to confirm the relationship between miR-381 and its target genes. The diagnostic and prognostic values of target genes were analyzed using publicly available data from The Cancer Genome Atlas. The Mann-Whitney U test and logistic regression were performed to evaluate the association between ABCB1 or CTNNB1 expression and clinical features in patients with liver hepatocellular carcinoma (LIHC). Finally, Kaplan-Meier and Cox regression analyses were performed to test the effect of ABCB1 or CTNNB1 expression on the overall survival of patients with LIHC. ABCB1 expression was upregulated in HepG2/Dox cells. ABCB1 was found to be a direct target of hsa-miR-381 and was negatively regulated by has-miR-381. Moreover, hsa-miR-381 directly targeted the CTNNB1 3' UTR and decreased the luciferase activity of CTNNB1. Transfection with miR-183 partially reversed chemotherapeutic drug resistance by downregulating the expression of ABCB1 and CTNNB1 in HepG2/Dox cells. Spearman's analysis results showed that CTNNB1 and ABCB1 were positively correlated in patients with liver cancer, and increased CTNNB1 and ABCB1 expression occurred in patients with liver cancer. High expression of ABCB1 and CTNNB1 indicated poor prognosis in patients with liver cancer; however, neither ABCB1 nor CTNNB1 expression was an independent diagnostic factor in patients with LIHC. Overexpression of hsa-miR-381 partially reversed the MDR of HepG2 cells by directly targeting and negatively regulating the expression of CTTNB1 and ABCB1. Moreover, high expression of ABCB1 or CTNNB1 indicated poor prognosis in patients with liver cancer.