title: Involvement of miR-326 in chemotherapy resistance of breast cancer through modulating expression of multidrug resistance-associated protein 1.
abstract: Multidrug resistance-associated protein (MRP-1/ABCC1) transports a wide range of therapeutic agents and may play a critical role in the development of multidrug resistance (MDR) in tumor cells. However, the regulation of MRP-1 remains controversial. To explore whether miRNAs are involved in the regulation of MRP-1 expression and modulate the sensitivity of tumor cells to chemotherapeutic agents, we analyzed miRNA expression levels in VP-16-resistant MDR cell line, MCF-7/VP, in comparison with its parent cell line, MCF-7, using a miRNA microarray. MCF-7/VP overexpressed MRP-1 mRNA and protein not MDR-1 and BCRP. miR-326 was downregulated in MCF-7/VP compared to MCF-7. Additionally, miR-326 was downregulated in a panel of advanced breast cancer tissues and consistent reversely with expression levels of MRP-1. Furthermore, the elevated levels of miR-326 in the mimics-transfected VP-16-resistant cell line, MCF-7/VP, downregulated MRP-1 expression and sensitized these cells to VP-16 and doxorubicin. These findings demonstrate for the first time the involvement of miRNAs in multidrug resistance mediated by MRP-1 and suggest that miR-326 may be an efficient agent for preventing and reversing MDR in tumor cells.
authors.affiliation: Department of Radiology, Emory University, Atlanta, GA 30322, USA. zliang@emory.edu
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liang
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.forename: James
authors.initials: J
authors.lastname: Xia
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Li
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ke
authors.initials: K
authors.lastname: Huang
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wagar
authors.forename: Younghyoun
authors.initials: Y
authors.lastname: Yoon
authors.forename: Heidi T
authors.initials: HT
authors.lastname: Cho
authors.forename: Stefania
authors.initials: S
authors.lastname: Scala
authors.forename: Hyunsuk
authors.initials: H
authors.lastname: Shim
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005047:Etoposide / Q000494:pharmacology; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: D000970:Antineoplastic Agents; D004317:Doxorubicin; D005047:Etoposide; D035683:MicroRNAs; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C545322:MIRN326 microRNA, human; C421109:multidrug resistance-associated protein 1