Mabuchi Seiji, Altomare Deborah A, Cheung Mitchell, Zhang Lili, Poulikakos Poulikos I, Hensley Harvey H, Schilder Russell J, Ozols Robert F, Testa Joseph R
Human Genetics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
Clin Cancer Res. 2007 Jul 15;13(14):4261-70. doi: 10.1158/1078-0432.CCR-06-2770.
mTOR (mammalian target of rapamycin) plays a central role in regulating cell growth and cell cycle progression and is regarded as a promising therapeutic target. We examined whether mTOR inhibition by RAD001 (everolimus) is therapeutically efficacious in the treatment of ovarian cancer as a single agent and in combination with cisplatin.
Using four human ovarian cancer cell lines, we determined the effect of RAD001 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Western blot, and apoptosis assays. We evaluated the association between phospho-AKT/mTOR activity and RAD001 sensitivity. We also determined the effect of RAD001 on tumor growth and malignancy using mice inoculated with human ovarian cancer cells.
RAD001 markedly inhibited cell proliferation of human ovarian carcinoma cells with high AKT activity (OVCAR10 and SKOV-3), but the effect was minimal in cells with low AKT activity (OVCAR4 and OVCAR5). Sensitivity to RAD001 was independent of p53 expression. RAD001 inhibited the phosphorylation of downstream 4E-BP1 and p70S6 kinase and attenuated the expression of Myc. RAD001 also attenuated the expression of HIF-1 alpha and vascular endothelial growth factor, important factors in angiogenesis and tumor invasiveness. RAD001 enhanced cisplatin-induced apoptosis in cells with high AKT/mTOR activity, with minimal effect in cells with low AKT-mTOR activity. Mouse xenografts of SKOV-3 cells revealed that RAD001 inhibits tumor growth, angiogenesis, and i.p. dissemination and ascites production and prolongs survival. Moreover, treatment with RAD001 significantly enhanced the therapeutic efficacy of cisplatin in vivo.
These results indicate that RAD001 could have therapeutic efficacy in human ovarian cancers with hyperactivated AKT/mTOR signaling.
雷帕霉素哺乳动物靶点（mTOR）在调节细胞生长和细胞周期进程中起核心作用，被视为一个有前景的治疗靶点。我们研究了雷帕霉素（RAD001，依维莫司）对mTOR的抑制作用作为单一药物以及与顺铂联合使用时对卵巢癌治疗是否有效。
使用四种人卵巢癌细胞系，我们通过3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐、蛋白质免疫印迹法和凋亡检测来确定RAD001的作用。我们评估了磷酸化AKT/mTOR活性与RAD001敏感性之间的关联。我们还使用接种人卵巢癌细胞的小鼠确定了RAD001对肿瘤生长和恶性程度的影响。
RAD001显著抑制具有高AKT活性的人卵巢癌细胞（OVCAR10和SKOV-3）的细胞增殖，但对具有低AKT活性的细胞（OVCAR4和OVCAR5）影响极小。对RAD001的敏感性与p53表达无关。RAD001抑制下游4E-BP1和p70S6激酶的磷酸化，并减弱Myc的表达。RAD001还减弱了HIF-1α和血管内皮生长因子的表达，这两者是血管生成和肿瘤侵袭中的重要因子。RAD001增强了顺铂诱导的具有高AKT/mTOR活性细胞的凋亡，对具有低AKT-mTOR活性的细胞影响极小。SKOV-3细胞的小鼠异种移植显示，RAD001抑制肿瘤生长、血管生成以及腹腔播散和腹水产生，并延长生存期。此外，RAD001治疗显著增强了顺铂在体内的治疗效果。
这些结果表明，RAD001对AKT/mTOR信号过度激活的人卵巢癌可能具有治疗效果。
