State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-Sen University, Guangzhou, China.
Br J Pharmacol. 2012 Jul;166(5):1669-83. doi: 10.1111/j.1476-5381.2012.01849.x.
Besides targeting the well-known oncogenic c-Met, crizotinib is the first oral tyrosine kinase inhibitor inhibiting anaplastic lymphoma kinase (ALK) in clinical trials for the treatment of non-small cell lung cancer. Here, we assessed the possible reversal of multidrug resistance (MDR) by crizotinib in vitro and in vivo.
1-(4,5-Dimethylthiazol-2-yl)-3,5- diphenylformazan was used in vitro and xenografts in nude mice were used in vivo to investigate reversal of MDR by crizotinib. To understand the mechanisms for MDR reversal, the alterations of intracellular doxorubicin or rhodamine 123 accumulation, doxorubicin efflux, ABCB1 expression level, ATPase activity of ABCB1 and crizotinib-induced c-Met, Akt and ERK1/2 phosphorylation were examined.
Crizotinib significantly enhanced the cytotoxicity of chemotherapeutic agents which are also ABCB1 substrates, in MDR cells with no effect found on sensitive cells in vitro and in vivo. Additionally, crizotinib significantly increased intracellular accumulation of rhodamine 123 and doxorubicin and inhibited the drug efflux in ABCB1-overexpressing MDR cells. Further studies showed that crizotinib enhanced the ATPase activity of ABCB1 in a concentration-dependent manner. However, expression of ABCB1 was not affected, and reversal of MDR by crizotinib was not related to the phosphorylation of c-Met, Akt or ERK1/2. Importantly, crizotinib significantly enhanced the effect of paclitaxel against KBv200 cell xenografts in nude mice.
Crizotinib reversed ABCB1-mediated MDR by inhibiting ABCB1 transport function without affecting ABCB1 expression or blocking the Akt or ERK1/2 pathways. These findings are useful for planning combination chemotherapy of crizotinib with conventional chemotherapeutic drugs.
克唑替尼不仅靶向众所周知的致癌基因 c-Met，还是首个在临床试验中用于治疗非小细胞肺癌的、抑制间变性淋巴瘤激酶（ALK）的口服酪氨酸激酶抑制剂。在此，我们评估了克唑替尼在体外和体内逆转多药耐药（MDR）的可能性。
采用 1-(4,5-二甲基噻唑-2-基)-3,5-二苯基四唑鎓（MTT）法在体外和裸鼠异种移植瘤模型中在体内研究克唑替尼逆转 MDR 的作用。为了研究 MDR 逆转的机制，检测了细胞内阿霉素或罗丹明 123 蓄积、阿霉素外排、ABCB1 表达水平、ABCB1 三磷酸腺苷酶（ATPase）活性以及克唑替尼诱导的 c-Met、Akt 和 ERK1/2 磷酸化的改变。
克唑替尼显著增强了也是 ABCB1 底物的化疗药物对 MDR 细胞的细胞毒性，而对敏感细胞无影响，在体外和体内均如此。此外，克唑替尼显著增加了 ABCB1 过表达的 MDR 细胞内罗丹明 123 和阿霉素的蓄积，并抑制了药物外排。进一步的研究表明，克唑替尼以浓度依赖的方式增强了 ABCB1 的 ATPase 活性。然而，ABCB1 的表达不受影响，且克唑替尼逆转 MDR 与 c-Met、Akt 或 ERK1/2 的磷酸化无关。重要的是，克唑替尼显著增强了紫杉醇对裸鼠 KBv200 细胞异种移植瘤的疗效。
克唑替尼通过抑制 ABCB1 转运功能逆转 ABCB1 介导的 MDR，而不影响 ABCB1 的表达或阻断 Akt 或 ERK1/2 通路。这些发现有助于规划克唑替尼与传统化疗药物联合化疗的方案。
