miR-195 Regulates Proliferation and Apoptosis through Inhibiting the mTOR/p70s6k Signaling Pathway by Targeting HMGA2 in Esophageal Carcinoma Cells

Dis Markers. 2017:2017:8317913. doi: 10.1155/2017/8317913. Epub 2017 Apr 9.

Abstract

miR-195 is related to tumorigenesis and frequently inhibits cell proliferation and promotes apoptosis in various cancers, including esophageal carcinoma (EC). The mTOR/p70s6k signaling pathway, which is the major target pathway for HMGA2, regulates the survival and cell proliferation of many tumors and is commonly active in EC. The relationships of miR-195, HMGA2, and the mTOR/p70s6k signaling pathway in EC, however, remain unknown. In the present study, we found that the miR-195 level was significantly downregulated in EC tissues, while the mRNA expressions of HMGA2 were significantly upregulated. Dual-luciferase reporter assay demonstrated that HMGA2 is a target of miR-195. MTT assay and flow cytometry revealed that miR-195 overexpression inhibited cell proliferation and induced apoptosis by targeting HMGA2. We also found that HMGA2 restored the inhibitory effect of miR-195 on phosphorylation of mTOR and p70S6K. Furthermore, rapamycin, a specific inhibitor of the mTOR/p70S6K signaling pathway, decreased the levels of Ki-67 and Bcl-2/Bax ratio, inhibited cell proliferation, and promoted apoptosis in EC cells. In conclusion, upregulation of miR-195 significantly suppressed cell growth and induced apoptosis of EC cells via suppressing the mTOR/p70s6k signaling pathway by targeting HMGA2.

MeSH terms

  • Apoptosis*
  • Carcinoma / genetics
  • Carcinoma / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation*
  • Esophageal Neoplasms / genetics
  • Esophageal Neoplasms / metabolism*
  • Gene Expression Regulation, Neoplastic
  • HMGA2 Protein / genetics*
  • HMGA2 Protein / metabolism
  • Humans
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • HMGA2 Protein
  • MIRN195 microRNA, human
  • MicroRNAs
  • Ribosomal Protein S6 Kinases, 70-kDa
  • TOR Serine-Threonine Kinases