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Research Area
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Description
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Solid tumours, Non-small cell lung cancer |
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Biological Activity
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Description
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GDC-0941 is a potent inhibitor of PI3Kα, PI3Kβ, PI3Kδ and PI3Kγ with IC50 of 3 nM, 33 nM, 3 nM and 75 nM, respectively. |
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Targets
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PI3Kα |
PI3Kβ |
PI3Kδ |
PI3Kγ |
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IC50 |
3 nM |
33 nM |
3 nM |
75 nM [1] |
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In Vitro
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GDC-0941 is equipotent against PI3Kα and PI3Kδ as well as PI3Kα mutants E545-K and H1047-R, displaying modest levels of selectivity against PI3Kβ (10-fold) and PI3Kγ (25-fold), and greater levels of selectivity against members of PI3K class II, III, and IV, including C2β, Vps34, DNA-PK, and mTOR. GDC-0941 potently inhibits the phosphorylation of Akt in U87MG, PC3, and MDA-MB-361 cells with IC50 of 46 nM, 37 nM, and 28 nM, respectively. GDC-0941 inhibits the proliferation of U87MG, A2780, PC3, and MDA-MB-361 cells with IC50 of 0.95 μM, 0.14 μM, 0.28 μM, and 0.72 μM, respectively. [1] GDC-0941 treatment potently inhibits the proliferation of both trastuzumab-sensitive and -insensitive HER2-amplified cells with IC50 of 149-944 nM. GDC-0941 inhibits proliferation of HER2-amplified cells that harbor PIK3CA mutations with IC50 of <500 nm,="" and="" effectively="" inhibits="" both="" proliferation="" and="" viability="" of="" her2-amplified="" breast="" cancer="" cells="" that="" are="" resistant="" to="" trastuzumab="" due="" to="" pten="" loss.="">[2] GDC-0941 significantly inhibits the growth of HCT116, DLD1 and HT29 cells with GI50 of 1081 nM, 1070 nM and 157 nM, respectively. [4] |
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In Vivo
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Administration of GDC-0941 at 75 mg/kg/day displays significant inhibitory effect against established human U87MG glioblastoma xenografts in female NCr athymic mice, with tumor growth inhibition of 83%. [1] Oral administration of GDC-0941 at 150 mg/kg/day inhibits the growth of HER2-amplified, trastuzumab-resistant MDA-MB-361.1 xenografts in mice, and significantly delays the tumor progression, in association with potent induced apoptosis in tumors. [2] GDC-0941 (75 mg/kg/day) treatment for 2 weeks induces ~40% reduction in tumor volume of spontaneous B-cell follicular lymphomas developed in PTEN+/-LKB1+/hypo mice, accompanied by ablation of phosphorylation of Akt, S6K and SGK (serum and glucocorticoid protein kinase) protein kinases. Consistently, GDC-0941 inhibits tumor cell proliferation, induces apoptosis and suppresses centroblast population. [3] |
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Clinical Trials
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A Phase I study of GDC-0941 in patients with locally advanced or metastatic solid tumors, Non-Hodgkin's lymphoma, or multiple myeloma (MM) (expansion stage only) for which standard therapy either does not exist or has proven ineffective or intolerable is currently ongoing. |
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Features
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Combination Therapy
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Description
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GDC-0941 (50 nM) in combination with Trastuzumab (10 μg/mL) synergistically inhibits the PI3K/Akt pathway with a 67% reduction in pAkt compared to 50 nM GDC-0941 treatment alone, and efficiently blocks the compensatory effect (elevated pHER3) from PI3K inhibition, resulting in a synergistic effect on the proliferation of Trastuzumab-sensitive breast cancer cells. The combination also significantly increases caspase activity and induces apoptosis, reducing the required doses by 4-10 fold compared with GDC-0941 treatment alone. GDC-0941 combined with Trastuzumab is more efficient in inhibition of the trastuzumab-sensitive BT474-M1 xenografts in mice than either of the single agents. [2] GDC-0941 in combination with MEK inhibitor either AZD6244 or PD0325901 exhibits greater synergistic growth inhibition against HCT116, DLD1 and HT29 cells, compared with the combinations with NVP-BEZ235, which can be compromised by mTORC1/2 inhibitor KU0063794 due to inhibition of mTOR. [4] A Phase I study of GDC-0941 in combination with GDC-0973 in patients with locally advanced or metastatic solid tumors is currently ongoing. |
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Protocol
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Kinase Assay
[1]
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| Scintillation proximity assay |
Recombinant human PI3Kα, PI3Kβ, and PI3Kδ are coexpressed in a Sf9 baculovirus system with the p85α regulatory subunit and purified as GST-fusion proteins using affinity chromatography on glutathione-sepharose. Recombinant human PI3Kγ is expressed as monomeric GST-fusions and purified similarly. GDC-0941 is dissolved in DMSO and added to 20 mM Tris-HCl (pH 7.5) containing 200 μg yttrium silicate (Ysi) polylysine SPA beads, 4 mM MgCl2, 1 mM dithiothreitol (DTT), 1 μM ATP, 0.125 μCi [γ-33P]-ATP, and 4% (v/v) DMSO in a total volume of 50 μL. The recombinant GST-fusion of PI3Kα (5 ng), PI3Kβ (5 ng), PI3Kδ (5 ng), or PI3Kγ (5 ng) is added to the assay mixture to initiate the kinase reaction. After incubation for 1 hour at room temperature, the kinase reaction is terminated with 150 μL PBS. The mixture is then centrifuged for 2 minutes at 2000 rpm and read using a Wallac Microbeta counter. The reported IC50 values are calculated using a sigmoidal, dose-response curve fit in MDL Assay Explorer. |
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Cell Assay
[2]
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| Cell Lines |
SKBR-3, BT474-M1, AU-565, HCC-1419, ZR75-30, KPL-4, JIMT-1, BT474-EEI, HCC-1954, MCF-7, CALU-3, SKOV-3, and MKN-7 cells |
| Concentrations |
Dissolved in DMSO, final concentrations ~10 μM |
| Incubation Time |
48 and 72 hours |
| Methods |
Cells are exposed to various concentrations of GDC-0941 for 48, and 72 hours. Proliferation/viability of cells is detected by using the CellTiter-Glo Luminescent Cell Viability Assay. The pAkt (Ser473), cleaved caspase-3, and cleaved PARP are analyzed by western blot. The Caspase-Glo 3/7 assay and the Cell Death Detection ELISAplus assay are used to detect caspase 3/7 activity, and apoptosis, respectively. |
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Animal Study
[2]
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| Animal Models |
NCR nude mice implanted with MDA-MB-361.1 cells, and SCID, C.B-17/IcrHsd-Prkdcscid mice implanted subcutaneously with BT474-M1 cells |
| Formulation |
Dissolved in 10% DMSO, 5% Tween 20, 85% water |
| Doses |
~150 mg/kg/day |
| Administration |
Oral gavage |
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References |
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[1] Folkes AJ, et al. J Med Chem, 2008, 51(18), 5522-5532.
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[2] Junttila TT, et al. Cancer Cell, 2009, 15(5), 429-440.
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[3] García-Martínez JM, et al. Br J Cancer, 2011, 104(7), 1116-1125.
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[4] Haagensen EJ, et al. Br J Cancer, 2012, 106(8), 1386-1394.
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