Pan J, Xu G, Yeung S C
Section of Endocrine Neoplasia and Hormonal Disorders, Department of Internal Medicine Specialties, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
J Clin Endocrinol Metab. 2001 Oct;86(10):4731-40. doi: 10.1210/jcem.86.10.7860.
We previously demonstrated that the combination of a farnesyltransferase inhibitor, manumycin A, and paclitaxel had a synergistic antineoplastic effect on anaplastic thyroid cancer. In this study we investigated the apoptosis pathway involved. In ARO and KAT-4 cells, manumycin- plus paclitaxel-induced DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8, and caspase-3. The drug combination enhanced the activation of caspase-9, caspase-8, and caspase-3 and cytochrome c release into the cytosol. Cytochrome c release was not affected by the inhibitors of caspase-9, caspase-8 and caspase-3. In a cell-free reconstitution assay, DNA fragmentation occurred after incubating nuclei purified from untreated KAT-4 cells with deoxy-ATP, exogenous cytochrome c and S-100 extracts from control KAT-4 cells, and also after incubation of purified KAT-4 nuclei with S-100 extracts from KAT-4 cells treated with manumycin-plus-paclitaxel. In both cases, the DNA fragmentation was blocked by the inhibitors of caspase-9, caspase-8 and caspase-3. We concluded that the cytochrome c release was upstream of the activation of caspase-9, caspase-8, and caspase-3 in the enhanced apoptosis of anaplastic thyroid cancer cells treated with manumycin plus paclitaxel, and that the interaction between manumycin and paclitaxel occurred at or upstream of cytochrome c in the apoptosis regulatory pathway in anaplastic thyroid cancer cells.
我们之前证明，法尼基转移酶抑制剂马尼霉素A与紫杉醇联合用药对间变性甲状腺癌具有协同抗肿瘤作用。在本研究中，我们调查了其中涉及的凋亡途径。在ARO和KAT-4细胞中，马尼霉素与紫杉醇联合诱导的DNA片段化被半胱天冬酶-9、半胱天冬酶-8和半胱天冬酶-3的抑制剂阻断。药物联合增强了半胱天冬酶-9、半胱天冬酶-8和半胱天冬酶-3的激活以及细胞色素c释放到细胞质中。细胞色素c的释放不受半胱天冬酶-9、半胱天冬酶-8和半胱天冬酶-3抑制剂的影响。在无细胞重建试验中，用脱氧三磷酸腺苷、外源性细胞色素c和来自未处理KAT-4细胞的S-100提取物孵育从未处理KAT-4细胞中纯化的细胞核后，以及用马尼霉素加紫杉醇处理的KAT-4细胞的S-100提取物孵育纯化的KAT-4细胞核后，均出现DNA片段化。在这两种情况下，DNA片段化均被半胱天冬酶-9、半胱天冬酶-8和半胱天冬酶-3的抑制剂阻断。我们得出结论，在用马尼霉素加紫杉醇处理的间变性甲状腺癌细胞增强的凋亡过程中，细胞色素c的释放发生在半胱天冬酶-9、半胱天冬酶-8和半胱天冬酶-3激活的上游，并且马尼霉素与紫杉醇之间的相互作用发生在间变性甲状腺癌细胞凋亡调节途径中细胞色素c处或其上游。
