Deforolimus is a selective mTOR inhibitor with IC50 of 0.2 nM; while not classified as a prodrug, mTOR inhibition and FKBP12 binding is similar to rapamycin.
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. 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.
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.
|
