Everolimus (RAD001) is a potent mTOR inhibitor that binds to FKBP-12 to generate an immunosuppressive complex.
Description :
A potent, highly specific, orally active mTOR inhibitor with IC50 of 5-6 nM for binding to FKBP-12 or FKBP-12 complexed to mTOR; inhibits proliferation in vitro (IC50=1 nM-1 uM) in sensitive and insensitive tumor; dose-dependently inhibits tumor growth in vivo.
Kidney Cancer
Everolimus exhibits the immunosuppressive activity which is comparable to that of rapamycin. Everolimus competes with immobilized FK 506 for binding to biotinylated FKBP12 and shows the inhibitory effect on a two-way MLR performed with spleen cells from BALB/c and CBA mice with IC50 of 0.12-1.8 nM. [1] Everolimus also shows antiangiogenic/vascular effects in VEGF-induced HUVEC proliferation with IC50 of 0.12 nM and bFGF-induced HUVEC proliferation with IC50 of 0.8 nM, respectively. [2] A recent study shows that Everolimus shows a dose-dependent inhibitory effects on both the total cells and the stem cells from the BT474 cell line and the primary breast cancer cells with IC50 of 156 nM in total cells of primary breast cancer cells and 71 nM in total cells of BT474 cells. In addition, combination treatment with Everolimus and trastuzumab produces the significantly increased inhibition on the growth of cancer stem cells with the inhibition rate increased by more than 50 %. [3]
Everolimus is orally active in both mice and rats, producing an antitumor effect that is characterized by dramatic reduction in tumor growth rates as opposed to producing tumor regressions. In the rat CA20498 model, daily treatment with Everolimus (0.5 or 2.5 mg/kg) dose-dependently inhibits growth, and intermittent dosing using a higher dose of 5 mg/kg (once or twice per week) also shows similar antitumor efficacy. Inhibition by Everolimus is characterized by sustained suppression rather than regression and is not associated with any body weight loss[1]. The effect of Everolimus treatment (0.1-10 mg/kg/d) is selective and differ from the effects of PTK/ZK (100 mg/kg). With either growth factor, Everolimus dose-dependently increases the hemoglobin content (convert to blood equivalents and indicative of the number of vessels as well as vascular leakiness) but reduces the Tie-2 content (number of endothelial cells indicative of the number of vessels) and this is significant for VEGF stimulation but not bFGF stimulation. The pharmacokinetics of Everolimus in mice shows that maximum levels of only 0.1 μM are achieved in a human tumor xenograft following a single administration, whereas plasma levels reach 1 to 3 μM for ~4 h[2].