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.
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).


CONCLUSIONS
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.
Moser
Christian
C
Department of Surgery, Regensburg Medical Center, Regensburg, Germany. christian.moser@klinik.uni-regensburg.de
Lang
Sven A
SA
Mori
Akira
A
Hellerbrand
Claus
C
Schlitt
Hans J
HJ
Geissler
Edward K
EK
Fogler
William E
WE
Stoeltzing
Oliver
O
D020533:Angiogenesis Inhibitors / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D004963:Estrenes / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000097:blood / Q000098:blood supply / Q000188:drug therapy* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D050257:Tubulin Modulators / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
C530263:2-methoxyoestra-1,3,5(10),16-tetraene-3-carboxamide; D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D004963:Estrenes; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050257:Tubulin Modulators; D042461:Vascular Endothelial Growth Factor A