Krüppel-like factor 8 regulates VEGFA expression and angiogenesis in hepatocellular carcinoma

Sci Rep. 2018 Nov 27;8(1):17415. doi: 10.1038/s41598-018-35786-6.

Abstract

Tumor angiogenesis plays a critical role in hepatocellular carcinoma (HCC) development and progression, but its mechanism is unclear. Krüppel-like factor 8 (KLF8) is a transcription factor that plays an important role in HCC progression. Here, we investigated the role of KLF8 in angiogenesis in HCC and its possible mechanism. Immunohistochemistry, quantitative RT-PCR, western blotting, promoter reporter assays, chromatin immunoprecipitation (ChIP), and chicken chorioallantoic membrane (CAM) and nude mouse tumor models were used to show that the mRNA and protein expression levels of KLF8 and VEGFA are highly correlated in HCC tissue samples. The up-regulation of KLF8 increased VEGFA protein levels and induced VEGFA promoter activity by binding to the CACCC region of the VEGFA promoter. In addition, KLF8 regulated HIF-1α and Focal adhesion kinase (FAK) expression. The PI3K/AKT inhibitor LY294002 inhibited KLF8-induced VEGFA expression, whereas PI3K/AKT signaling pathway proteins, such as P-PDK1(Ser241) and P-AKT(Thr308), were decreased significantly. KLF8-overexpressing HCC cells had a higher potential for inducing angiogenesis. Thus, our results indicate that KLF8 may induce angiogenesis in HCC by binding to the CACCC region of the VEGFA promoter to induce VEGFA promoter activity and through FAK to activate PI3K/AKT signaling to regulate HIF-1α expression levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carcinoma, Hepatocellular / metabolism*
  • Carcinoma, Hepatocellular / pathology
  • Cell Line, Tumor
  • Focal Adhesion Protein-Tyrosine Kinases / metabolism
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Kruppel-Like Transcription Factors
  • Liver Neoplasms / metabolism*
  • Liver Neoplasms / pathology
  • Mice
  • Mice, Nude
  • Neovascularization, Pathologic / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Promoter Regions, Genetic
  • Proto-Oncogene Proteins c-akt / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Signal Transduction
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • KLF8 protein, human
  • Kruppel-Like Transcription Factors
  • Repressor Proteins
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Focal Adhesion Protein-Tyrosine Kinases
  • Proto-Oncogene Proteins c-akt