[Description]:
Ganetespib is a heat shock protein 90 (HSP90) inhibitor which exhibits potent cytotoxicity in a wide variety of hematological and solid tumor cell lines.
[Related Catalog]:
[Target]
[In Vitro]
Ganetespib causes depletion of receptor tyrosine kinases, extinguishing of downstream signaling, inhibition of proliferation and induction of apoptosis with IC50 values ranging 2-30 nM in genomically-defined NSCLC cell lines. Ganetespib is also approximately 20-fold more potent in isogenic Ba/F3 pro-B cells rendered IL-3 independent by expression of EGFR and ERBB2 mutants[1]. Ganetespib exhibits potent in vitro cytotoxicity in a range of solid and hematologic tumor cell lines, induces the degradation of known Hsp90 client proteins, displays superior potency to the ansamycin inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG)[2]. Ganetespib is a potent HSP90 inhibitor, and shown to kill canine tumor cell lines in vitro[3]. Ganetespib possesses superior JAK/STAT inhibitory activity to both P6 and 17-AAG in terms of potency or duration of response in the HEL92.1.7 cells[4].
[In Vivo]
Ganetespib (125 mg/kg, i.v.) accumulates in tumors relative to normal tissues and displays greater in vivo efficacy than 17-AAG without increased toxicity and inhibits proliferation and induces apoptosis in parallel with EGFR depletion in NCI-H1975 xenografts[1]. Ganetespib (100, 125, 150 mg/kg, i.v.) shows potent antitumor efficacy in solid and hematologic xenograft models of oncogene addiction, as evidenced by significant growth inhibition and/or regressions[2].
[Kinase Assay]
Exponentially growing cells are processed in lysis buffer (20 mM HEPES, pH 7.4, 1 mM EDTA, 5 mM MgCl2, 100 mM KCl) and incubated with increasing concentrations of 17-AAG or ganetespib for 30 min at 4°C, and incubated with biotin-GM linked to Dynabeads MyOne Streptavidin T1 magnetic beads for 1 h at 4°C. Beads are washed three times in lysis buffer and heated for 5 min at 95°C in SDS-PAGE sample buffer. Samples are resolved on 4-12% Bis-Tris gradient gel and Western blots are performed using an anti-HSP90 antibody.
[Cell Assay]
Cells are grown in 96-well plates based on optimal growth rates determined empirically for each line. Twenty-four hours after plating, cells are treated with the indicated compounds or controls for 72 hours. AlamarBlue is added (10% v/v) to the cells, and the plates are incubated for 3 hours and, then, subjected to fluorescence detection. For the comparative viability/apoptosis assay, NCI-H1975 cells are treated with escalating concentrations of ganetespib for the indicated time periods and subjected to viability analysis via CellTiter Fluor and apoptosis via Caspase Glo 3/7.
[Animal admin]
Mice: NCI-H1975 or HCC827 cells are cultured as above and 0.5-1×107 cells are mixed with 50% RPMI 1640/50% Matrigel and subcutaneously injected into the flanks of SCID mice. For efficacy studies, animals with 100-200 mm3 tumors are then randomized into treatments groups of eight. Tumor volumes (V) are calculated by the equation V=0.5236×L×W×T (Length, width, and thickness). Animals are treated by intravenous bolus tail vein injection at 10 mL/kg with ganetespib formulated in 10/18 DRD (10% DMSO, 18% Cremophor RH 40, 3.6% dextrose and 68.4% water). As a measurement of in vivo efficacy, the relative size of treated and control tumors [(%T/C) value] is determined from the change in average tumor volumes of each drug-treated group relative to the vehicle-treated group, or itself in the case of tumor regression. Body weights are monitored daily. For biomarker studies, mice bearing NCI-H1975 xenografts are treated with either a single dose of vehicle or ganetespib, or with 5 daily doses of vehicle or ganetespib, in groups of 3 or 8, and harvested at various time points. Tumors are excised and flash frozen in liquid nitrogen for preparation of protein lysates or fixed in 10% neutral buffered formalin for immunohistochemistry.
[References]
[1]. Shimamura T, et al. Ganetespib (STA-9090), a Non-Geldanamycin HSP90 Inhibitor, has Potent Antitumor Activity in In Vitro and In Vivo Models of Non-Small Cell Lung Cancer. Clin Cancer Res. 2012 Jul 17.
[2]. Ying W, et al. Ganetespib, a unique triazolone-containing Hsp90 inhibitor, exhibits potent antitumor activity and a superior safety profile for cancer therapy. Mol Cancer Ther. 2012 Feb;11(2):475-84.
[3]. London CA, et al. Phase I evaluation of STA-1474, a prodrug of the novel HSP90 inhibitor ganetespib, in dogs with spontaneous cancer.PLoS One. 2011;6(11):e27018.
[4]. Proia DA, et al. Multifaceted intervention by the Hsp90 inhibitor ganetespib (STA-9090) in cancer cells with activated JAK/STAT signaling. PLoS One. 2011 Apr 14;6(4):e18552.
[5]. Stewart E, et al. Identification of Therapeutic Targets in Rhabdomyosarcoma through Integrated Genomic, Epigenomic, and Proteomic Analyses. Cancer Cell. 2018 Sep 10;34(3):411-426.e19.
[Related Small Molecules]