Hepatocyte growth factor induced up-regulations of VEGF through Egr-1 in hepatocellular carcinoma cells.
The potential role of hepatocyte growth factor (HGF) in the regulation of angiogenesis factors in hepatoma cells is not widely appreciated. We investigated the role of HGF-induced activation of a transcription factor, Egr-1, in the expression of pro-angiogenic factors. Genes associated with angiogenesis induced by HGF were screened by using cDNA microarray technology in hepatocellular carcinoma cell lines, HepG2 and Hep3B. Expression levels of Egr-1, vascular endothelial growth factor (VEGF), and interleukin (IL)-8 were further confirmed by real time RT-PCR and Western blot analysis. Roles of Egr-1 in the levels of HGF-induced up-regulations of VEGF and IL-8 were measured by knockdown of Egr-1 with Egr-1 shRNA and chromatin immunoprecipitation assay. The levels of Egr-1, VEGF and IL-8 were up-regulated in cells treated with HGF. HGF-induced up-regulations of Egr-1, VEGF, and IL-8 were inhibited by the pretreatment with an MEK inhibitor, PD098059. HGF-induced up-regulation of VEGF and IL-8 were repressed by Egr-1 knockdown. HGF enhanced the binding activity of Egr-1 to the VEGF promoter in control cells, but not in the Egr-1-shRNA cells. No constitutive and inducible Egr-1 binding activities to the IL-8 promoter were observed in control and Egr-1-shRNA cells. Egr-1 knockdown reduced the luciferase activities increased by HGF not in the IL-8 promoter, but in the VEGF promoter. Egr-1 might play an important role in the up-regulation of VEGF and IL-8 induced by HGF and contribute to HGF-mediated angiogenesis, which might be promising targets for hepatocellular carcinoma therapy.
Lee
Kyung Hee
KH
Department of Hemato-Oncology, College of Medicine, Yeungnam University, Daegu 705-717, Republic of Korea. lkhee@med.yu.ac.kr
Kim
Jae-Ryong
JR
D001483:Base Sequence; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers; D051766:Early Growth Response Protein 1 / Q000502:physiology*; D055785:Gene Knockdown Techniques; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000502:physiology*
D017931:DNA Primers; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D016209:Interleukin-8; D042461:Vascular Endothelial Growth Factor A; D017228:Hepatocyte Growth Factor