Ridaforolimus (AP23573) is a small molecule and non-prodrug analogue of the lipophilic macrolide antibiotic rapamycin with potential antitumor activity. Ridaforolimus binds to and inhibits the mammalian target of rapamycin (mTOR), which may result in cell cycle arrest and, consequently, the inhibition of tumor cell growth and proliferation. Upregulated in some tumors, mTOR is a serine/threonine kinase involved in regulating cellular proliferation, motility, and survival that is located downstream of the PI3K/Akt signaling pathway.

mTOR (HT-1080 cells):0.2 nM

Deforolimus以剂量依赖性方式在携带PC-3（前列腺）,HCT-116（结肠）,MCF7（乳房）,PANC-1（胰腺）或A549（肺）异种移植物的小鼠中发挥显著的抗肿瘤作用,在与抑制肿瘤生长相关的SK-LMS-1异种移植模型中抑制mTOR信号传导.

Deforolimus剂量依赖性抑制HT-1080细胞中S6和4E-BP1磷酸化,IC50分别为0.2 nM和5.6 nM,EC50分别为0.2 nM和1.0 nM,且导致细胞尺寸减小,G1期细胞增多,抑制葡萄糖摄取,EC50为0.1-1 nM。Deforolimus作用于一组细胞系,具有显著抗增殖活性,EC50为0.2-2.3 nM。Deforolimus有效且选择性及剂量依赖性抑制VEGF产量,EC50为~0.1 nM。Deforolimus和MEK抑制剂CI-1040或 PD0325901联用作用于人肺癌细胞系,具有协同作用,这种作用存在剂量依赖性,这种作用与细胞增殖受抑制而非细胞凋亡增多相关,处理24小时后,抑制40%核糖体合成,且使多核糖体/染色单体比例下降。Deforolimus显著抑制人NSCLC细胞系（除了H157细胞）细胞生长,IC30为2.45-8.83 nM,而作用于H157细胞时,IC30 >20 nM。2.8-5.9 nM Deforolimus处理A549,H1703和H157细胞（除了表达mTORC1耐药变异的H1666）,使p70S6KThr389去磷酸化,提高A549和H1703细胞中pAKTser473和pAKTThr308磷酸化水平。

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 by the inhibition of levels of phosphorylated ribosomal protein S6 (p-S6) and 4E-BP1 (p-4E-BP1).

Cell lines: Colo205,H1755,H1395,H1666,A549,H157,and H1703 cells. Concentrations: Dissolved in ethanol,final concentrations ~ 1 μM. Method: 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 by the CellTiter 96 Aqueous nonradioactive cell proliferation assay and Sulforhodamine B assays.

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. Dosages: ~10 mg/kg. Administration: Intraperitoneally injection