title: HIF-1α Induces Multidrug Resistance in Gastric Cancer Cells by Inducing MiR-27a.
abstract: This study aimed to determine the correlation between HIF-1α and miR-27a expression and to evaluate the effect of inhibition of HIF-1α expression on miR-27a expression and drug resistance in gastric cancer (GC). In the present study, real time-PCR and Western blot were performed to detect the expression of HIF-1α in GC tissues and cell lines. Then, OCUM-2MD3/L-OHP cells were transfected with HIF-1α-siRNA, a miR-27a mimic or pcDNA-HIF-1α, and cell survival was determined via the MTT assay. The expression of HIF-1α, miR-27a, and MDR-related genes was measured via real time-PCR and Western blot. ChIP and dual luciferase activity assays were performed to assess the transcriptional regulation of HIF-1α and miR-27a. The results revealed that transfection with HIF-1α-siRNA markedly decreased the levels of miR-27a, resulting in dramatically enhanced inhibition of the proliferation rate of OCUM-2MD3/L-OHP cells. Compared to non-transfected cells, the survival rate was significantly reduced in the cells transfected with HIF-1α-siRNA after treatment with L-OHP. The cell survival rate was significantly increased in OCUM-2MD3/L-OHP cells transfected with the miR-27a mimic, whereas HIF-1α overexpression did not result in any clear change in cell survival. The results of the dual luciferase activity assay demonstrated that HIF-1α enhances the transcriptional activity of the miR27a promoter in cells transfected with a reporter plasmid containing the upstream promoter region of miR27a together with pcDNA-HIF-1α. ChIP analysis suggested that HIF-1α directly binds to the promoter region of miR27a. Inhibition of HIF-1α or miR27a expression decreased MDR1/P-gp, LRP, and Bcl-2 expression in OCUM-2MD3/L-OHP cells. Thus, we found that HIF-1α is closely associated with MDR in GC and that HIF-1α may suppress MDR1/P-gp, LRP and Bcl-2 expression by inhibiting miR-27a expression.
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Qun
authors: Q
authors: Zhao
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Yong
authors: Y
authors: Li
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Bi-Bo
authors: BB
authors: Tan
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Li-Qiao
authors: LQ
authors: Fan
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Pei-Gang
authors: PG
authors: Yang
authors: Department of General Surgery, the Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, China.
authors: Yuan
authors: Y
authors: Tian
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D019450:Genes, MDR / Q000235:genetics; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics*; D014162:Transfection / Q000379:methods
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C531388:MIRN27 microRNA, human; D035683:MicroRNAs; D034741:RNA, Small Interfering