Involvement of miR-133a and miR-326 in ADM resistance of HepG2 through modulating expression of ABCC1

Abstract

Recent studies have shown that a class of small, functional RNAs, named microRNAs, may regulate multidrug resistance-associated protein 1 (ABCC1). Since ABCC1 is an important efflux transporter responsible for cellular drug disposition, the discovery of microRNAs (miRNA) brings an idea that there may be some other unknown multidrug resistance (MDR) mechanisms exist. Using computational programs, we predicted that the 3'untranslated region (3'UTR) of ABCC1 contains a potential miRNA binding site for miR-133a and also two other for miR-326. These binding sites were confirmed by luciferase reporter assay. ABCC1 mRNA degradation was accelerated dramatically in cells transfected with miR-133a or miR-326 mimics using qRT-PCR, Furthermore, western blot analysis indicated that ABCC1 protein expression was significantly down-regulated in hepatocellular carcinoma cells line HepG2 after transfection with miR-133a or miR-326 mimics, suggesting the involvement of mRNA degradation and protein expression mechanism. The effects of the two miRNAs on adriamycin (ADM) sensitivity to HepG2 cells were determined by MTT assay. Compared with mock transfection, miR-133a or miR-326 mimics transfection sensitized these cells to ADM. These findings for the first time demonstrated that the involvement of miR-133a and miR-326 in MDR is mediated by ABCC1 in hepatocellular carcinoma cell line HepG2 and suggested that miR-133a and miR-326 may be efficient agents for preventing and reversing ADM resistance in cancer cells.

MicroRNA-133a functions as a tumor suppressor by targeting IGF-1R in hepatocellular carcinoma

“…Recently, growing pieces of evidence have shown that miR-133a acts as a tumor suppressor in prostate cancer [17], bladder cancer [18], head and neck cancer [19], esophageal cancer [20], and colorectal cancer [21], suggesting that miR-133a may serve as a potential therapeutic gene for the treatment of these cancers. Although a recent study has demonstrated that miR-133a could regulate multidrug resistance mediated by targeting multidrugresistance-associated protein 1 (ABCC1) in HCC cell line HepG2 [22], the clinical importance of miR-133a in HCC progression, the detailed function, and underlying molecular mechanism of miR-133a in HCC have not yet been thoroughly validated.…”

miR-17-5p down-regulation contributes to erlotinib resistance in non-small cell lung cancer cells

“…Recent evidence suggests that dys-regulation of miRNAs plays a vital role in regulating the drug response of tumor cells [8,[30][31][32]. For instance, miR-133a and miR-326 are involved in adriamycin resistance in HepG2 cells through altering expression of multidrug resistance-associated protein 1 (ABCC1) [33]. Moreover, p53 suppresses miR-520 g expression, which mediates drug resistance through down-regulation of p21 [34].…”

MicroRNA Pharmacoepigenetics: Posttranscriptional Regulation Mechanisms behind Variable Drug Disposition and Strategy to Develop More Effective Therapy

“…Further studies demonstrated that miR-326 directly acted on the 39UTR of ABCC1, reduced ABCC1 mRNA and protein expression, and sensitized drug-resistant MCF-7 cells to chemotherapy (Liang et al, 2010). Other ABCC1 regulatory miRNAs evaluated by biologic experiments include miR-134 and miR-7 in small cell lung cancer cells (Guo et al, 2010;Liu et al, 2015), miR-1291 in pancreatic cancer cells (Pan et al, 2013), and miR-133a in hepatocarcinoma cells (Ma et al, 2015). Likewise, restoring the expression or function of such ABCC1 regulatory miRNAs increased intracellular drug accumulation and chemosensitivity, supporting the feasibility of miRNA-based strategies to improve therapy (Fig.…”