RBFOX3 Regulates the Chemosensitivity of Cancer Cells to 5-Fluorouracil via the PI3K/AKT, EMT and Cytochrome-C/Caspase Pathways

Cell Physiol Biochem. 2018;46(4):1365-1380. doi: 10.1159/000489153. Epub 2018 Apr 18.

Abstract

Background/aims: RBFOX3, an RNA-binding fox protein, plays an important role in the differentiation of neuronal development, but its role in the chemosensitivity of hepatocellular carcinoma (HCC) to 5-FU is unknown.

Methods: In this study, we examined the biological functions of RBFOX3 and its effect on the chemosensitivity of HCC cells to 5-FU in vitro and in a mouse xenograft model.

Results: RBFOX3 was found to have elevated expression in HCC cell lines and tissue samples, and its knockdown inhibited HCC cell proliferation. Moreover, knockdown of RBFOX3 improved the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and enhanced the apoptosis induced by 5-FU. However, overexpression of RBFOX3 reduced the inhibitory effect of 5-fluorouracil (5-FU) on cell proliferation, migration and invasion, and decreased the apoptosis induced by 5-FU. We further elucidated that RBFOX3 knockdown synergized with 5-FU to inhibit the growth and invasion of HCC cells through PI3K/AKT and epithelial-mesenchymal transition (EMT) signaling, and promote apoptosis by activating the cytochrome-c/caspase signaling pathway. Finally, we validated that RBFOX3 regulated 5-FU-mediated cytotoxicity in HCC in mouse xenograft models.

Conclusions: The findings from this study indicate that RBFOX3 regulates the chemosensitivity of HCC to 5-FU in vitro and in vivo. Therefore, targeting RBFOX3 may improve the inhibition of HCC growth and progression by 5-FU, and provide a novel potential therapeutic strategy for HCC.

Keywords: 5-fuorouracil (5-FU); Hepatocellular carcinoma (HCC); Rbfox3.

MeSH terms

  • Animals
  • Antigens, Nuclear / genetics
  • Antigens, Nuclear / metabolism*
  • Apoptosis / drug effects
  • Carcinoma, Hepatocellular / drug therapy
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Caspases / metabolism
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Cytochromes c / metabolism
  • Drug Resistance, Neoplasm / drug effects*
  • Epithelial-Mesenchymal Transition / drug effects*
  • Fluorouracil / therapeutic use
  • Fluorouracil / toxicity*
  • Humans
  • Liver Neoplasms / drug therapy
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • Mice
  • Mice, Nude
  • Microscopy, Fluorescence
  • Neoplasm Metastasis
  • Nerve Tissue Proteins / antagonists & inhibitors
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Signal Transduction / drug effects*
  • Transplantation, Heterologous

Substances

  • Antigens, Nuclear
  • Nerve Tissue Proteins
  • RNA, Small Interfering
  • neuronal nuclear antigen NeuN, human
  • Cytochromes c
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • Caspases
  • Fluorouracil