ENMD-1198, a novel tubulin-binding agent reduces HIF-1alpha and STAT3 activity in human hepatocellular carcinoma(HCC) cells, and inhibits growth and vascularization in vivo

BMC Cancer. 2008 Jul 23;8:206. doi: 10.1186/1471-2407-8-206.

Abstract

Background: Hepatocellular carcinoma (HCC) represents a highly vascularized tumor entity and the process of angiogenesis is essential for the growth of HCC. Importantly, the pro-angiogenic transcription factors HIF-1alpha and STAT3 have been implicated in HCC progression, thus representing interesting targets for molecular targeted therapy. We hypothesized that therapeutic inhibition of HIF-1alpha could be achieved by using a novel tubulin-binding agent (ENMD-1198). ENMD-1198 is an analog of 2-methoxyestradiol (2ME2) with antiproliferative and antiangiogenic activity.

Methods: The human HCC cell lines HUH-7 and HepG2 were used for experiments. Effects of ENMD-1198 on constitutive and inducible (hypoxia, growth factors) activation of signaling cascades, including HIF-1alpha and STAT3, were investigated by Western blotting. Changes in VEGF expression were determined by real-time PCR. Effects of ENMD-1198 on cancer cell migration and invasion were evaluated in in vitro-assays. The growth-inhibitory effects of ENMD-1198 (200 mg/kg/day) were determined in a subcutaneous tumor model (HUH-7).

Results: ENMD-1198 inhibited the phosphorylation of MAPK/Erk, PI-3K/Akt and FAK. Moreover, activation of HIF-1alpha and STAT3 was dramatically reduced by ENMD-1198, which resulted in lower VEGF mRNA expression (P < 0.05). In addition, tumor cell migratory and invasive properties were significantly inhibited (P < 0.05, for both). In vivo, treatment with ENMD-1198 led to a significant reduction in tumor growth, tumor vascularization, and numbers of proliferating tumor cells (P < 0.05 for all).

Conclusion: The novel microtubule destabilizing agent ENMD-1198 is suitable for inhibiting HIF-1alpha and STAT3 in human HCC cells and leads to reduced tumor growth and vascularization in vivo. Hence, inhibition of HIF-1alpha and STAT3 could prove valuable for therapy of hepatocellular carcinoma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inhibitors / pharmacology
  • Antineoplastic Agents / pharmacology*
  • Carcinoma, Hepatocellular / blood
  • Carcinoma, Hepatocellular / blood supply
  • Carcinoma, Hepatocellular / drug therapy*
  • Carcinoma, Hepatocellular / pathology
  • Cell Line, Tumor
  • Estrenes / pharmacology*
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / antagonists & inhibitors
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Liver Neoplasms / blood
  • Liver Neoplasms / blood supply
  • Liver Neoplasms / drug therapy*
  • Liver Neoplasms / pathology
  • Neovascularization, Pathologic / drug therapy*
  • Reverse Transcriptase Polymerase Chain Reaction
  • STAT3 Transcription Factor / antagonists & inhibitors
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism
  • Transcriptional Activation / drug effects
  • Tubulin Modulators / pharmacology*
  • Vascular Endothelial Growth Factor A / biosynthesis
  • Vascular Endothelial Growth Factor A / genetics

Substances

  • 2-methoxyoestra-1,3,5(10),16-tetraene-3-carboxamide
  • Angiogenesis Inhibitors
  • Antineoplastic Agents
  • Estrenes
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Tubulin Modulators
  • Vascular Endothelial Growth Factor A