State Key Laboratory in Oncology in South China, Sir YK Pao Center for Cancer, Department of Clinical Oncology, Cancer Drug Testing Unit, Hong Kong Cancer Institute, Li Ka Shing Institute of Health Sciences and Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
Cancer Chemother Pharmacol. 2013 Jun;71(6):1417-25. doi: 10.1007/s00280-013-2139-4. Epub 2013 Apr 2.
RAD001 targets at the mammalian target of rapamycin (mTOR), while TKI-258 is a potent tyrosine kinase inhibitor targeting at fibroblast growth factor receptor, vascular endothelial growth factor receptor, platelet-derived growth factor receptor and c-kit. We aim to study the activity of combined RAD001 and TKI-258 in cell lines and xenograft model of hepatocellular carcinoma (HCC), with reference to the parallel and upstream pathways of Akt-mTOR axis.
A panel of 4 human HCC cell lines HepG2, Hep3B, PLC/PRF/5 and Huh7 and the Hep3B-derived xenograft were treated with TKI-258 or/and RAD001, respectively. Related mechanistic studies (including apoptosis and angiogenesis) were conducted.
There was an enhanced increase in suppression of cell proliferation with combined TKI-258 and RAD001 compared with either drug alone. The combination could significantly suppress the phosphorylation of mTOR, MEK1/2 and p38 MAPK. Although the addition of the TKI258 only slightly suppressed the phosphorylation of AKT induced by RAD001, the pi-mTOR and its downstream signaling pathways including pi-p70S6K, pi-S6 and pi-4EBP1 were lowered in the combination. In Hep3B-derived xenograft, TKI-258 and RAD001 had shown an enhanced inhibition of tumor growth without impact on the weight of animals. There was a reduction in microvessel density in the xenograft with the combination, which indicated an enhanced inhibition on angiogenesis. Pro-caspases-3 and PARP cleavage were slightly detected at 48 h after treatment, suggesting that the combination mainly increased the cytostatic arrest ability.
The combination of RAD001 and TKI-258 was active in HCC via inhibition of both mTOR-mediated signaling and its parallel pathways.
RAD001 靶向哺乳动物雷帕霉素靶蛋白（mTOR），而 TKI-258 是一种针对成纤维细胞生长因子受体、血管内皮生长因子受体、血小板衍生生长因子受体和 c-kit 的强效酪氨酸激酶抑制剂。我们旨在研究 RAD001 和 TKI-258 在肝癌（HCC）细胞系和异种移植模型中的活性，并参考 Akt-mTOR 轴的平行和上游途径。
我们用 TKI-258 或/和 RAD001 分别处理一组 4 个人肝癌细胞系 HepG2、Hep3B、PLC/PRF/5 和 Huh7 以及 Hep3B 衍生的异种移植瘤，进行相关的机制研究（包括凋亡和血管生成）。
与单独使用任一药物相比，联合使用 TKI-258 和 RAD001 可显著增强对细胞增殖的抑制作用。该联合用药可显著抑制 mTOR、MEK1/2 和 p38 MAPK 的磷酸化。虽然添加 TKI258 仅略微抑制了 RAD001 诱导的 AKT 磷酸化，但 pi-mTOR 及其下游信号通路包括 pi-p70S6K、pi-S6 和 pi-4EBP1 在联合用药中降低。在 Hep3B 衍生的异种移植瘤中，TKI-258 和 RAD001 联合应用可增强抑制肿瘤生长，而对动物体重无影响。联合用药可降低异种移植瘤中的微血管密度，表明血管生成抑制增强。在治疗后 48 小时，检测到 pro-caspases-3 和 PARP 裂解略有增加，表明联合用药主要增加了细胞周期停滞能力。
RAD001 和 TKI-258 的联合应用通过抑制 mTOR 介导的信号及其平行途径在 HCC 中具有活性。
