Ridaforolimus (Deforolimus, MK-8669)

MTOR

990, 21

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

Dissolved in ethanol, final concentrations ca. 1 uM

Dissolved in ethanol, and diluted in a vehicle of 4% ethanol, 5% Tween 80, and 5% propylene glycol

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]

72-120 hours

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.

Ridaforolimus (Deforolimus, MK-8669, AP23573) is a selective mTOR inhibitor with IC50 of 0.2 nM in HT-1080 cell line; while not classified as a prodrug, mTOR inhibition and FKBP12 binding is similar to rapamycin. Phase 3.