Cell experiment:

To determine IC50 for SK-HEP1 cells, cells are plated at a density of 2×104 cells per dish. After 48 h, cells are treated with 0, 0.01, 0.1, 1, 5, 10, 50, 100 μM dovitinib in DMEM containing 1% FBS for 24 h. Cell viability is determined with Cell Proliferation Assay. IC50 is calculated by nonlinear regression analysis using GraphPad Prism software[2].

Animal experiment:

Mice: Six HCC lines (06-0606, 26-0808A, 26-1004, 25-0705A, 5-1318, 21-0208) are used to establish tumors in male SCID mice. or dose-esponse experiments, mice bearing the 06-0606 xenografts re orally given vehicle (5% dextrose) or two doses of dovitinib (50 and 75 mg/kg) daily for 14 days. For time-dependent inhibition of dovitinib targets, mice bearing 06-0606 tumors are given orally 200 μL of either vehicle (n=6) or 50 mg/kg/day of dovitinib (n=10)[2].

Dovitinib(CHIR-258; TKI258) lactate is a potent inhibitor of fibroblast growth factor receptor 3 (FGFR3) with an IC50 of 5 nM.

Dovitinib potently inhibits FGFR3 with an IC50 of 5 nM in in vitro kinase assays and selectively inhibits the growth of B9 cells and human myeloma cell lines expressing wild-type or activated mutant FGFR3. Addition of interleukin 6 (IL-6) or insulin growth factor 1 or coculture on stroma does not confer resistance to dovitinib. In primary myeloma cells dovitinib inhibits downstream extracellular signal-regulated kinase (ERK) 1/2 phosphorylation with an associated cytotoxic response[1]. Treatment of SK-HEP1 cells with dovitinib results in G2/M cell cycle arrest, inhibition of colony formation in soft agar and blockade of bFGF-induced cell migration. Dovitinib inhibits basal expression and FGF-induced phosphorylation of FGFR-1, FRS2-α and ERK1/2[2].

Dovitinib demonstrates significant antitumor and antimetastatic activities in HCC xenograft models. Dovitinib potently inhibits tumor growth of six HCC lines. Inhibition of angiogenesis correlates with inactivation of FGFR/PDGFR-β/VEGFR-2 signaling pathways. Dovitinib also causes dephosphorylation of retinoblastoma, upregulation of p-histone H2A-X and p27, and downregulation of p-cdk-2 and cyclin B1, which results in a reduction in cellular proliferation and the induction of tumor cell apoptosis[2].

[1]. Trudel S, et al. CHIR-258, a novel, multitargeted tyrosine kinase inhibitor for the potential treatment of t(4;14) multiple myeloma. Blood. 2005, 105(7), 2941-2948. [2]. Huynh H, et al. Dovitinib demonstrates antitumor and antimetastatic activities in xenograft models of hepatocellular carcinoma. J Hepatol. 2012, 56(3), 595-601.