Description

Cancer

Description

GSK1838705A is a potent inhibitor of IGF-IR, IR and ALK with IC50 of 2.0 nM, 1.6 nM and 0.5 nM, respectively

Targets

IC₅₀

In Vitro

GSK1838705A potently and ATP-competitively inhibits IGF-IR and IR with ^appK_i values of 0.7 nM and 1.1 nM, respectively.In cells, GSK1838705A potently inhibits ligand-induced phosphorylation of IGF-IR and IR with IC50 of 85 nM and 79 nM, respectively. GSK1838705A shows the significant anti-proliferative effect in a panel of cell lines derived from solid and hematologic tumors such as L-82, SUP-M2, SK-ES and MCF-7 cells with EC50 of 24 nM, 28 nM, 141 nM and 203 nM, respectively. GSK1838705A shows an accumulation of MCF-7 and NCl-H929 cells predominantly in G1 (2N) phase of the cell cycle. GSK1838705A also inhibits ALK with K_i of 0.35 nM and supresses the proliferation of nucleophosmin (NPM)-ALK fusion cells with EC50 of 24-88 nM. GSK1838705A potently inhibits NPM-ALK phosphorylation in Karpas-299 and SR-786 cells, while has modest effect on STAT3 phosphorylation. ^[1]

In Vivo

In NIH-3T3/LISN tumor-bearing mice, oral treatment of GSK1838705A (60 mg/kg) cause tumor growth inhibition by 77%, without significant weight loss. In COLO 205 tumor–bearing mice, inhibition of tumor growth by GSK1838705A (30 mg/kg) is 80%. Besides, the antitumor efficacy of GSK1838705A is also observed in mice bearing HT29 xenograft or BxPC3 xenograft. In mice, GSK1838705A (60 mg/kg) leads to a transient 2-fold increase in blood glucose levels by inhibiting IR signaling. GSK1838705A (60 mg/kg) inhibits the growth of established Karpas-299 xenografts with 93% tumor growth inhibition, with no effect on weights of the rats. ^[1]

Clinical Trials

Features

GSK1838705A is a small-molecule kinase inhibitor of IGF-IR and the insulin receptor.

Kinase Assays

Baculovirus-expressed glutathione S-transferase–tagged proteins encoding the intracellular domain of IGF-IR (amino acids 957–1367) and IR (amino acids 979–1382) are used for determinations of IC50s by a homogeneous time-resolved fluorescence assay. A filter binding assay is used for appKi determinations using activated IGF-IR and IR kinases. Expanded kinase-selectivity profiling of GSK1838705A is carried out by screening the compound in the KinaseProfiler panel.

Cell Lines

L-82, SUP-M2, SK-ES and MCF-7

Concentrations

0 to 10 μM

Incubation Time

72 hours

Methods

Cells are seeded in 96-well dishes, incubated overnight at 37 °C, and treated with DMSO or GSK1838705A for 72 hours. For the NIH-3T3/LISN proliferation assays, cells are seeded on collagen-coated 96-well tissue culture plates and allowed to adhere for 24 hours. The medium is replaced with serum-free medium and the cells are treated with GSK1838705A for 2 hour. Cells are incubated for 72 hours after addition of IGF-I (30 ng/mL). Cell proliferation is quantified using the CellTiter-Glo Luminescent Cell Viability Assay. IC50s are determined from cytotoxicity curves using a four-parameter curve fit software package (XLfit4).

Animal Models

L-82, SUP-M2, SK-ES and MCF-7 cells are injected s.c. into the right flank of CD1 or SCID mice.

Formulation

GSK1838705A is dissolved in 20% sulfobutyl ether β-cyclodextrin (ISP; pH 3.5).

Doses

≤60 mg/kg

Administration

Administered via p.o.