Cabozantinib (XL184)

RET, MET, KIT

501, 51

RIP-Tag2 transgenic mice in a C57BL/6 background with spontaneous pancreatic islet tumors

XL184 is currently under Phase III study versus mitoxantrone plus prednisone in men with previously treated symptomatic castration-resistant prostate cancer (COMET-2).

ca.60 mg/kg

0.035 nM, 0.035 nM, 0.035 nM, 0.035 nM, 0.035 nM, 0.035 nM

XL184 treatment at 30 mg/kg in RIP-Tag2 mice with spontaneous pancreatic islet tumors disrupts 83% of the tumor vasculature, reduces pericytes and empty basement membrane sleeves, causes widespread intratumoral hypoxia and extensive tumor cell apoptosis, and slows regrowth of the tumor vasculature after drug withdrawal, more significantly compared with XL999 that blocks VEGFR but not c-Met, leading to only 43% reduction in vascularity, suggesting that concurrent inhibition of VEGFR and other functionally relevant receptor tyrosine kinases (RTK) amplifies angiogenesis inhibition. XL184 also decreases invasiveness of primary tumors and reduces metastasis. [1] XL184 at 30 mg/kg/day significantly abrogates human MPNST xenografts growth and metastasis in SCID mice. [2] Administration of XL184 induces dose-dependent inhibition of tumor growth in breast, lung, and glioma tumor models, in association with decreased tumor and endothelial cell proliferation as well as increased apoptosis. A single oral dose of XL184 is sufficient to induce sustained tumor growth inhibition in MDA-MB-231 tumor-bearing mice and C6 tumor-bearing rats at 100 mg/kg and 10 mg/kg, respectively. [3]

Cells are exposed to various concentrations of XL184 for 48 hours. Cell growth is determined by MTS assays using CellTiter96 Aqueous Non-Radioactive Cell Proliferation Assay kit. Absorbance is measured at a wavelength of 490 nm, and the absorbance values of treated cells are presented as a percentage of the absorbance of untreated cells.

Cabozantinib (XL184) is a potent VEGFR2 inhibitor with IC50 of 0.035 nM and also inhibits c-Met, Ret, Kit, Flt-1/3/4, Tie2, and AXL with IC50 of 1.3 nM, 4 nM, 4.6 nM, 12 nM/11.3 nM/6 nM, 14.3 nM and 7 nM in cell-free assays, respectively. Cabozantinib induces PUMA-dependent apoptosis in colon cancer cells via AKT/GSK-3β/NF-κB signaling pathway.