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Research Area
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Description
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Cancer |
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Biological Activity
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Description
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Deforolimus (Ridaforolimus, AP23573, MK-8669) is a selective mTOR inhibitor with IC50 of 0.2 nM. |
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Targets
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mTOR |
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IC50 |
0.2 nM [1] |
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In Vitro
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Treatment of HT-1080 cells with Deforolimus induces a dose-dependent inhibition of phosphorylation of both S6 and 4E-BP1, with IC50 of 0.2 nM and 5.6 nM, respectively, and leads to a decrease in cell size, an increase in the proportion of cells in the G1 phase of the cell cycle, and inhibition of glucose uptake. Deforolimus displays significant antiproliferative activity a broad panel of cell lines with EC50 of 0.2-2.3 nM. Deforolimus potently and selectively inhibits VEGF production in a dose-dependent manner. [1] Deforolimus treatment significantly induces growth suppression in human NSCLC cell lines with IC30 values of 2.45-8.83 nM, with the exception of H157 with IC30 of >20 nM. Deforolimus treatment (2.8-5.9 nM) significantly dephosphorylates p70S6KThr389 in A549, H1703 and H157 cells, except H1666 that may express a resistant variant of mTORC1, and causes increased phosphorylation of pAKTser473 and pAKTThr308 in A549 and H1703 cells. Deforolimus in combination with the MEK inhibitors, CI-1040 or PD0325901 exhibits dose-dependent synergism in lung cancer cell lines, which is associated with the suppression of proliferation rather than enhancement of cell death, involving the inhibition of ribosomal biogenesis by 40% within 24 hours and a decreased polysome/monosome ratio. [2] |
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In Vivo
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Administration of Deforolimus exerts significant antitumor effects in mice bearing PC-3 (prostate), HCT-116 (colon), MCF7 (breast), PANC-1 (pancreas) or A549 (lung) xenografts in a dose-dependent manner, and inhibits mTOR signaling in in SK-LMS-1 xenograft model associated with inhibition of tumor growth. [1] |
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Clinical Trials
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Features
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Combination Therapy
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Description
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Deforolimus combined with Lapatinib results in synergistic inhibition of proliferation, reduces anchorage-independent growth, and reduces in vivo tumor growth of HER2-overexpressing breast cancer cells that have primary trastuzumab resistance. [3] Deforolimus in combination with Bicalutamide produces synergistic antiproliferative effects in prostate cancer cells in vitro, and exhibits potent antitumor activity with parallel reductions in plasma PSA levels in vivo. [4] Deforolimus in combination with MK-2206 is highly effective for inhibiting castration-resistant prostate cancer (CRPC) in preclinical studies in vivo using a refined genetically engineered mouse model of the disease. [5] |
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Protocol
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Kinase Assay
[1]
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| Cell based target inhibition |
HT-1080 cells are treated with increasing concentrations of Deforolimus (0-100 nM) for 2 hours, prior to harvest. Cellular lysates are extracted in denaturing lysis buffer, resolved on SDS-PAGE and transferred to PVDF membranes. After blocking, membranes are incubated with primary antibodies for 1 hour, followed by appropriate HRPconjugated secondary antibodies for 1 hour at room temperature. Immunoreactive proteins are detected using enhanced chemiluminescence and autoradiography performed by exposure to X-ray film. IC50 is determined from the inhibition of levels of phosphorylated ribosomal protein S6 (p-S6) and 4E-BP1 (p-4E-BP1). |
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Cell Assay
[2]
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| Cell Lines |
Colo205, H1755, H1395, H1666, A549, H157, and H1703 cells |
| Concentrations |
Dissolved in ethanol, final concentrations ~ 1 μM |
| Incubation Time |
72-120 hours |
| Methods |
Cells are seeded at 2-3 × 104/mL, and serial dilutions of Deforolimus are added after 2 hours, for at least three cell doublings (72-120 hours). Deforolimus effects are measured using the CellTiter 96 Aqueous nonradioactive cell proliferation assay and Sulforhodamine B assays. For Deforolimus, growth effects are described as IC30 because rapamycin and its derivatives do not significantly impede cell proliferation. |
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Animal Study
[1]
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| Animal Models |
Male and female athymic NCr-nu mice with xenografts established by subcutaneous implantation of PC-3, A549, HCT-116, MCF7, PANC-1 and SK-LMS-1 tumors |
| Formulation |
Dissolved in ethanol, and diluted in a vehicle of 4% ethanol, 5% Tween 80, and 5% propylene glycol |
| Doses |
~10 mg/kg |
| Administration |
Intraperitoneally |
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References |
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[1] Rivera VM, et al. Mol Cancer Ther, 2011, 10(6), 1059-1071.
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[2] Legrier ME, et al. Cancer Res, 2007, 67(23), 11300-11308.
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[3] Gayle SS, et al. Anticancer Agents Med Chem, 2012, 12(2), 151-162.
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[4] Squillace RM, et al. Int J Oncol, 2012, 41(2), 425-432.
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[5] Floc'h N, et al. Cancer Res, 2012, 72(17), 4483-4493.
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