Targeting HCCR expression resensitizes gastric cancer cells to chemotherapy via down-regulating the activation of STAT3

Sci Rep. 2016 Apr 7:6:24196. doi: 10.1038/srep24196.

Abstract

The human cervical cancer oncogene (HCCR) has been found to be overexpressed in a variety of human cancers. However, the level of expression of HCCR and its biological function in gastric cancer are largely unknown. In this study, we evaluated HCCR expression in several gastric cancer cell lines and in one normal gastric mucosal cell line. We established a 5-FU-resistant gastric cancer cell subline, and we evaluated its HCCR expression. HCCR expression levels were high in gastric cancer lines, and expression was significantly increased in the 5-FU-resistant cancer cell subline. HCCR expression affected cell growth by regulating apoptosis in the cancer cells, and it had a positive correlation with p-STAT3 expression. Western blot and luciferase reporter assays showed that the activation of STAT3 upregulated HCCR expression in a positive feedback loop model. In vivo and in vitro studies showed that HCCR plays an important role in the apoptosis induced by 5-FU. Our data demonstrate that HCCR is probably involved in apoptosis and cancer growth and that it functions as a p-STAT3 stimulator in a positive feedback loop model. In gastric cancer cells, HCCR confers a more aggressive phenotype and resistance to 5-FU-based chemotherapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimetabolites, Antineoplastic / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Blotting, Western
  • Cell Line
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / genetics
  • Down-Regulation / drug effects
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / genetics
  • Fluorouracil / pharmacology*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Mice, Nude
  • Microscopy, Confocal
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins / metabolism
  • RNA Interference
  • RNAi Therapeutics / methods
  • Reverse Transcriptase Polymerase Chain Reaction
  • STAT3 Transcription Factor / metabolism*
  • Stomach Neoplasms / drug therapy*
  • Stomach Neoplasms / genetics
  • Stomach Neoplasms / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Antimetabolites, Antineoplastic
  • LETMD1 protein, human
  • Proto-Oncogene Proteins
  • STAT3 Transcription Factor
  • Fluorouracil