title: MiR-27a modulates MDR1/P-glycoprotein expression by targeting HIPK2 in human ovarian cancer cells.
abstract: OBJECTIVE
  MicroRNAs (miRNAs) are non-coding, single-stranded small RNAs that regulate gene expression negatively, which is involved in fundamental cellular processes and the initiation, development and progression of human cancer. In this study, we investigated the role of miR-27a in the development of drug resistance in ovarian cancer cells.
  
  
  METHODS
  Expression of miR-27a in ovarian cancer cell lines A2780 and A2780/Taxol were detected by stem-loop real-time PCR. A2780 and A2780/Taxol cells were transfected with the mimics or inhibitors of miR-27a or negative control RNA (NC) by Lipofectamine 2000. The expression levels of MDR1 mRNA, P-glycoprotein (P-gp) and Homeodomain-interacting protein kinase-2 (HIPK2) proteins were assessed by real-time PCR and western blot respectively. Drug sensitivity was analyzed by MTT assay while apoptosis and the fluorescence intensity of intracellular Rhodamine 123 (Rh-123) were measured by FACS.
  
  
  RESULTS
  The expression levels of miR-27a and P-gp were up-regulated in paclitaxel-resistant ovarian cancer cell line A2780/Taxol as compared with its parental line A2780. Transfection of A2780/Taxol cells with the inhibitors of miR-27a decreased the expression of MDR1 mRNA and P-gp protein, increased HIPK2 protein expression, enhanced the sensitivity of A2780/taxol cells to paclitaxel, increased paclitaxel-induced apoptosis and the fluorescence intensity of intracellular Rh-123. Expression of MDR1 mRNA was increased while the sensitivity to paclitaxel was decreased in A2780 cells management with the mimics of miR-27a.
  
  
  CONCLUSIONS
  The deregulation of miR-27a may be involved in the development of drug resistance, regulating the expression of MDR1/P-gp, at least in part, by targeting HIPK2 in ovarian cancer cells.
authors.affiliation: Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Li
authors.forename: Sha
authors.initials: S
authors.lastname: Hu
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.forename: Lan
authors.initials: L
authors.lastname: Xiao
authors.forename: Lili
authors.initials: L
authors.lastname: Yu
authors.forename: Zehua
authors.initials: Z
authors.lastname: Wang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002352:Carrier Proteins; C531388:MIRN27 microRNA, human; D035683:MicroRNAs; C115114:HIPK2 protein, human; D017346:Protein Serine-Threonine Kinases; D017239:Paclitaxel