title: 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.
authors.affiliation: Institute of Pharmacy and Pharmacology, University of South China , Hengyang , P.R. China .
authors.forename: Jin
authors.initials: J
authors.lastname: Ma
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yang
authors.forename: Jie
authors.initials: J
authors.lastname: Yin
authors.forename: Jia
authors.initials: J
authors.lastname: Yu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Xiang
authors.forename: Xia
authors.initials: X
authors.lastname: Pan
authors.forename: Huifang
authors.initials: H
authors.lastname: Tang
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Lei
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D056945:Hep G2 Cells; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis / Q000235:genetics*; D014162:Transfection
chemical_list: D004317:Doxorubicin; D035683:MicroRNAs; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C548234:MIRN133 microRNA, human; C545322:MIRN326 microRNA, human; C421109:multidrug resistance-associated protein 1
keywords: ABCC1; adriamycin; hepatocellular carcinoma; microRNA