Inhibition of tumor cell growth, invasion, and metastasis by SIM-89, a novel inhibitor of HGF receptor tyrosine kinases.

Abstract

e13528 Background: The Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), are overexpressed and/or activated in a wide variety of human malignancies. SIM-89, developed by Simcere Bio-Pharmaceutical Co, Ltd, is a small-molecule kinase inhibitor that targets members of the HGF receptor tyrosine kinase families. Methods: Kinase inhibition was investigated using Z-lyte detection technique(Invitrogen), LanthaScreen Tb-activity technique and LanthaScreen Binding technique. Inhibition of p-Met and Met is validated through Westernblot. IC50 of the compound is determined by CCK-8. HGF level in culture medium is determined by ELISA.Migration and invasion assayare done with Transwell system. A549 and H460(2×106)are implanted subcutaneous in right upper extremity of nude mice.Once daily oral administration of SIM-89/ placebo are given to nude mice for 35d.Tumor growth curve is calculated. B16F10 tumor cells (2 × 105) were implanted via i.v. tail vein injection into mice on day 0. SIM-89/ placebo administration was initiated 3 days after implantation for 10 days followed by assessment of lung tumor burden. Lung nodule diameters were morphometrically measured on digitally captured images. The results for each treatment group (n = 10 animals) were averaged, and statistical t test analysis was done comparing each treatment group to the placebo treated control. Results: SIM-89 is a small-molecule kinase inhibitor that targets members of the HGF receptor tyrosine kinase families,with additional inhibitory activity toward AMPK (A1/B1/G1) and TRKA. SIM-89 significantly decreases HGF level in culture medium of nsclc cell lines at the IC50 of 625nmol/l. In vivo, these effects produce significant dose-dependent inhibition of tumor burden in an experimental model of lung metastasis. Once daily oral gavage administration of SIM-89 resulted in a dose-dependent reduction in tumor burden, as determined by a reduction in lung wet weights. Conclusions: These data indicate that SIM-89 may prevent tumor growth through a direct effect on tumor cell proliferation and by inhibition of invasion mediated by HGF receptors.