HIF-1α Induces Multidrug Resistance in Gastric Cancer Cells by Inducing MiR-27a

PLoS One. 2015 Aug 20;10(8):e0132746. doi: 10.1371/journal.pone.0132746. eCollection 2015.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Proliferation / genetics
  • Cell Survival / genetics
  • Drug Resistance, Multiple / genetics*
  • Drug Resistance, Neoplasm / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Genes, MDR / genetics
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics*
  • Male
  • MicroRNAs / genetics*
  • Middle Aged
  • Promoter Regions, Genetic / genetics
  • RNA, Small Interfering / genetics
  • Stomach Neoplasms / genetics*
  • Transfection / methods

Substances

  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • MIRN27 microRNA, human
  • MicroRNAs
  • RNA, Small Interfering

Grants and funding

This work was supported by the following grant: The Provincial Natural Science Foundation of Hebei Province (No. H2013206311 to Qun Zhao).