Malignant gliomas are characterized by high invasive potential and strong angiogenic ability. Constitutive activation of Rho and its downstream target Rho-kinase are crucial for tumor progression. We investigated the effect of the Rho-kinase inhibitor HA1077 on tumor-induced angiogenesis of malignant glioma cells and explored the molecular mechanisms underlying the effect of HA1077. Here, we demonstrated that HA1077 suppressed tube formation of endothelial cells in human umbilical vein endothelial cell (HUVEC)-glioma cell co-culture assay. Western blot, RT-PCR, ELISA and zymography demonstrated that HA1077 suppressed gene and protein expressions of vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2 and MMP-9 in glioma cells. Furthermore, HA1077 attenuated the phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and the DNA binding activity of activator protein-1, a key downstream transcriptional factor of ERK1/2. HA1077 also suppressed the migration of HUVEC in vitro. Thus, it is suggested that the anti-angiogenic effect of HA1077 may be due to the combination of ROCK inhibition and mitogen-activated protein kinase kinase (MEK)/ERK pathway inhibition. Moreover, an in vivo intracerebral human glioma cell xenograft mouse model demonstrated that HA1077 suppressed neovascularity and tumor growth. The results of the present study suggest that HA1077 has a therapeutic potential as an anti-angiogenic agent against malignant gliomas.
© 2010 Japanese Cancer Association.