Kinase experiment:

Ten centimeter square dishes are seeded with 2 million cells in a volume of 10 mL followed by incubation at 37℃ under 5% CO2 overnight (appr 16 hours). Cells are treated with the indicated concentration of GDC-0941, Apitolisib (GDC-0980), or mTOR1/2 inhibitor for the time indicated. Following treatment, cells are washed with cold PBS and lysed in 1X Cell Extraction Buffer, 1 mM PMSF, and Phosphatase Inhibitor Cocktails 1 and 2 are all needed. Protein concentration is determined using the Pierce BCA Protein Assay Kit. For immunoblots, equal protein amounts are separated by electrophoresis through NuPage Bis-Tris 10% gradient gels; proteins are transferred onto polyvinylidene difluoride membranes using the Criterion system and protocol.

Cell experiment:

Three hundred and eighty-four-well plates are seeded with 2,000 cells/well in a volume of 54 μL per well followed by incubation at 37℃ under 5% CO2 overnight (appr 16 hours). Compounds are diluted in dimethyl sulfoxide to generate the desired stock concentrations then added in a volume of 6 μL per well. All treatments are tested in quadruplicate. After 4 days incubation, relative numbers of viable cells are estimated using CellTiter-Glo and total luminescence is measured on a Wallac Multilabel Reader. The concentration of drug resulting in 50% inhibition of cell viability (IC50) or 50% maximal effective concentration (EC50) is determined using Prism software. For cell lines that failed to achieve an IC50 the highest concentration tested (20 μM) is listed.

Animal experiment:

Human prostate cancer PC3 cells are resuspended in Hank’s Balanced Salt Solution and 3×106 cells implanted subcutaneously into the right hind flank of athymic nu/nu (nude) mice. Tumors are monitored until they reach a mean tumor volume of 150-200 mm3 prior to the initiation of dosing. MCF7.1 cells resuspended in a 1:1 mixture of Hank’s Buffered Salt Solution and Matrigel Basement Membrane Matrix are 5×106 subcutaneously implanted into the right hind flank of athymic nu/nu (nude) mice. Prior to cell inoculation, 17β-estradiol (0.36 mg/pellet, 60-day release, no. SE-121) are implanted into the dorsal shoulder blade area of each nude mouse. After implantation of cells, tumors are monitored until they reach a mean tumor volume of 250-350 mm3 prior to initiating dosing. Compound 2 is dissolved in 0.5% methylcellulose with 0.2% Tween-80 (MCT). Female nude (nu/nu) mice that are 6-8 weeks old and weighed 20-30 g are obtained from Charles River Laboratories. Tumor bearing mice are dosed daily for 14-21 days depending on the xenograft model with 100 μL of vehicle (MCT) or test agent orally.

GDC-0980 (RG7422) is a selective, novel, potent and orally bioavailable inhibitor of class 1 PI3K/mTOR kinase with the Ki value of 17nmol/L for mTOR kinase [1].

GDC-0980 (RG7422) has shown the effective inhibition with the IC50 values of ＜200nmol/L in prostate, breast and NSCLC lines, respectinely. In addition, GDC-0980 (RG7422) has been reported to reduce cell viability in KPL4 cells by cell-cycle inhibition and induction of apoptosis with the IC50 value of 109nM and the EC50 value of 78nM. Furthermore, GDC-0980 (RG7422) has been revealed to significantly inhibit tumor responses in xenograft models in oral dose of the compound. Besides, GDC-0980 (RG7422) has been noted to enhance the antitumor activity in combination with antitumor agents ( docetaxel) in vivo [1].

References:
[1] Wallin JJ1, Edgar KA, Guan J, Berry M, Prior WW, Lee L, Lesnick JD, Lewis C, Nonomiya J, Pang J, Salphati L, Olivero AG, Sutherlin DP, O'Brien C, Spoerke JM, Patel S, Lensun L, Kassees R, Ross L, Lackner MR, Sampath D, Belvin M, Friedman LS. GDC-0980 is a novel class I PI3K/mTOR kinase inhibitor with robust activity in cancer models driven by the PI3K pathway. Mol Cancer Ther. 2011 Dec;10(12):2426-36. doi: 10.1158/1535-7163.MCT-11-0446. Epub 2011 Oct 13.