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Biological Activity
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Description
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CH5132799 exhibits a strong inhibitory activity especially against PI3Kα with IC50 of 14 nM. |
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Targets
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PI3Kα |
PI3Kβ |
PI3Kδ |
PI3Kγ |
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IC50 |
0.014 μM |
0.12 μM |
0.50 μM |
0.036 μM [1] |
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In Vitro
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CH5132799 selectively inhibits class I PI3Ks, PI3Kα (IC50 = 0.014 μM ), PI3Kβ (IC50 = 0.12 μM ), PI3Kδ (IC50 = 0.50 μM ), PI3Kγ (IC50 = 0.036 μM ), but shows less inhibition of class II PI3Ks, class III PI3k and mTOR and also no inhibitory activity (IC50 > 10 μM) against 26 protein kinases. CH5132799 exhibits more inhibitory activities against PI3Kα with oncogenic mutations E542K (IC50 = 6.7 nM), E545K (IC50 = 6.7 nM) and H1047R (IC50 = 5.6 nM) than wild-type PI3Kα. CH5132799 treated breast cnacer KPL-4 cells, which harbor the PIK3CA mutation, phosphorylation of Akt and its direct substrates, PRAS40 and FoxO1/3a and phosphorylation of downstream factors, including S6K, S6 and 4E-BP1, are effectively suppressed. Cancer cell lines harboring PIK3CA mutations are significantly sensitive to CH5132799 [1] In human tumor cell lines with PI3K pathway activation by mutation, CH5132799 shows potent antiproliferative activity [HCT116(CRC): IC50 = 0.20 lM, KPL-4(BC):13 IC50 = 0.032 lM, T-47D(BC): IC50 = 0.056 lM, SK-OV-3(Ovarian): IC50 = 0.12 lM]. CH5132799 effectively suppresses phosphorylation of AKT in KPL-4 cells. [2] |
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In Vivo
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CH5132799 shows potent in vivo antitumor activity in several different xenograft models with PIK3CA mutations. CH5132799 overcomes mTORC1 inhibition-mediated Akt activation and regrowth of xenograft tumor by long-term everolimus administration. [1] CH5132799 as a clinical candidate that shows excellent oral bioavailability (BA) (101% in mouse), human liver microsomal stability and in vivo antitumor activity in the PC-3 xenograft model (TGI: 101% at 25 mg/kg, po, q.d. × 11 days). CH5132799 exhibits good oral BA in mouse, rat, monkey and dog (F: 54.2–101%, Table 2). In a human breast cancer (KPL-4: PI3Ka H1047R) xenograft model in mice, oral treatment with CH5132799 (12.5 mg/kg, q.d.) shows strong tumor regression. The strong regression is maintained during the 6 week administration, even in the intermittent dosing schedule (q.d., 2 weeks on/1 week off; q.d., 5 days on/2 days off), suggesting that a flexible administration schedule can be applicable in the clinic. [2] |
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Clinical Trials
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CH5132799 is now in Phase 1 clinic trial fro the orally administration in human with advanced solid tumors. |
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Features
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Combination Therapy
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Description
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Combination with CH5132799 and trastuzumab, tumors disappears in the trastuzumab-insensitive breast cancer model with the PIK3CA mutation. [1] |
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Protocol
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Kinase Assay
[1]
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| PI3K Assay |
The E542K, E545K, and H1047R mutants of PI3Kα are prepared with an overlapped extension-polymerase chain reaction. Glutathione S-transferase-tagged PI3Kα mutants and His-tagged p85α are co-expressed with BAC-TO-BAC Baculovirus Expression System. The inhibitory activities of CH5132799 on PI3Kα (p110α/p85α), PI3Kβ(p110β/p85α), PI3Kδ (p110δ/p85α), PI3Kγ (p110γ), PI3KC2α, PI3KC2β, Vps34, and PI3Kα mutants are determined by Adapta Universal Kinase Assay Kit. Time-resolved fluorescence is measured with an EnVision HTS microplate reader. IC50 values are calculated using XLfit. |
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Cell Assay
[1]
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| Cell Lines |
various cancer cell lines belonging to 4 types of cancer—breast, ovarian, prostate, and endometrial cancer—in which the PIK3CA mutation and PTEN deficiency are frequently found and in which RAS/RAF is rarely mutated |
| Concentrations |
0 – 10μM |
| Incubation Time |
4 days |
| Methods |
The cell lines are added to the wells of 96-well plates containing 0.076 to 10,000 nM CH5132799 and incubated at 37 °C. After 4 days of incubation, Cell Counting Kit-8 solution is added and, after incubation for several more hours, absorbance at 450 nm is measured with Microplate-Reader iMark. The antiproliferative activity is calculated by the formula (1- T/C) × 100 (%), in which T and C represent absorbance at 450 nm of the cells treated with CH5132799 (T) and that of untreated control cells (C). The IC50 values are calculated by using Microsoft Excel 2007. |
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Animal Study
[1]
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| Animal Models |
A total of 4 × 106 to 1.2 × 107 cells are injected subcutaneously into the right flank of female BALB-nu/nu mice. |
| Formulation |
CH5132799 is dissolved in DMSO. |
| Doses |
0.39, 0.78, 1.56, 3.13, 6.25, 12.5 and 25 mg/kg |
| Administration |
Orally administered once a day. |
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References |
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[1] Tanaka H, et al, Clin Cancer Res, 2011, 17(10), 3272-3281.
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[2] Ohwada J, et al, Bioorg Med Chem Leff, 2011, 21(6), 1767-1772.
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