MicroRNA-218 promotes cisplatin resistance in oral cancer via the PPP2R5A/Wnt signaling pathway

Oncol Rep. 2017 Oct;38(4):2051-2061. doi: 10.3892/or.2017.5899. Epub 2017 Aug 11.

Abstract

Accumulating data suggest that microRNAs (miRNAs) play a pivotal role in the regulation of tumor cell sensitivity to chemotherapeutic agents. Although the roles of a few miRNAs have been identified in cisplatin resistance, little is known in regards to the concerted contribution of miRNA‑mediated biological networks. In the present study, we demonstrated that microRNA-218 (miR-218) was significantly upregulated in cisplatin-resistant oral cancer cells. The results of cell viability and apoptosis assay showed that ectopic expression of miR-218 induced cell survival and resistance to cisplatin, whereas suppression of miR-218 caused apoptosis and enhanced sensitivity to cisplatin. Moreover, we identified PPP2R5A as a new direct target of miR-218 by using the dual luciferase reporter assay. Overexpression of miR-218 led to inhibition of PPP2R5A expression, whereas knockdown of miR-218 increased PPP2R5A levels. Introduction of PPP2R5A abrogated miR‑218-mediated cell survival and drug resistance. Furthermore, suppression of miR-218 or PPP2R5A significantly promoted or reduced cisplatin-induced apoptosis, respectively. Finally, PPP2R5A overexpression or β-catenin knockdown inhibited miR-218-mediated Wnt activation and partially restored cell sensitivity. Our data revealed a molecular link between miR-218 and PPP2R5A/Wnt signaling and implicates miR-218 as a potential target for oral cancer therapy.

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • Cisplatin / pharmacology*
  • Drug Resistance, Neoplasm
  • Gene Knockdown Techniques
  • Humans
  • MicroRNAs / biosynthesis
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Mouth Neoplasms / drug therapy*
  • Mouth Neoplasms / genetics
  • Mouth Neoplasms / metabolism*
  • Protein Phosphatase 2 / metabolism*
  • Up-Regulation
  • Wnt Signaling Pathway*

Substances

  • Antineoplastic Agents
  • MIRN218 microRNA, human
  • MicroRNAs
  • PPP2R5A protein, human
  • Protein Phosphatase 2
  • Cisplatin