Celastrol enhances TRAIL-induced apoptosis in human glioblastoma via the death receptor pathway
Celastrol enhances TRAIL-induced apoptosis in human glioblastoma via the death receptor pathway
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DOI：
10.1007/s00280-019-03900-8
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发表时间：
2019-10-01
影响因子：
3
通讯作者：
Yu, Huarong
中科院分区：
文献类型：
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作者：
Cha, Zhe;Cheng, Jianzhang;Yu, Huarong
目的胶质母细胞瘤是最常见、最恶性、最具破坏性的原发性脑肿瘤。肿瘤坏死因子相关凋亡诱导配体（tumor necrosis factor-related apoptosis-induced ligand，TRAIL）对癌前病变和癌细胞具有杀伤作用。然而，许多肿瘤细胞，包括大多数胶质瘤细胞，倾向于逃避TRAIL诱导的凋亡。雷公藤红素是一种来自传统中药的多效性化合物，已被证明可用作TRAIL治疗的敏化剂。然而，雷公藤红素在神经胶质瘤细胞致敏中的潜在机制和作用仍有待阐明。方法采用CCK-8法检测胶质瘤细胞株的存活率。逆转录实时荧光定量PCR检测DR 5的表达。Western blot检测DR 5、cleaved caspase-8、cleaved caspase-3和PARP蛋白表达。流式细胞仪检测细胞凋亡率和亚G1期细胞数。TUNEL法检测细胞凋亡，Hoechst 33258染色检测细胞形态学变化。通过siRNA进行DR 5表达的敲低。结果雷公藤红素对胶质瘤和正常人星形胶质细胞系的细胞活力有抑制作用，且呈剂量依赖性，而TRAIL对胶质瘤和正常人星形胶质细胞系的细胞活力无明显影响。我们还观察到TRAIL与非细胞毒性浓度的雷公藤红素组合的抗增殖作用显著大于单独的雷公藤红素或TRAIL。此外，联合处理诱导的细胞死亡是凋亡性的，并通过死亡受体途径通过激活半胱天冬酶-8、半胱天冬酶-3和PARP发生。此外，雷公藤红素在mRNA和蛋白质水平上调死亡受体5（DR 5），并且siRNA介导的DR 5敲低降低了组合药物治疗对胶质瘤细胞的杀伤作用，并降低了半胱天冬酶-3、半胱天冬酶-8和PARP的活化。结论雷公藤红素通过死亡受体途径使胶质瘤细胞对TRAIL敏感，DR 5在协同治疗中起重要作用。结果表明，这种联合治疗是一种有前途的高效低毒的肿瘤杀伤治疗策略。
Purpose Glioblastoma is the most common, malignant and devastating type of primary brain tumor. Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) is characterized by its lethality to precancerous and cancerous cells. However, many kinds of tumor cells, including most glioma cells, tend to evade TRAIL-induced apoptosis. Celastrol is a pleiotropic compound from a traditional Chinese medicine that has proven to be useful as a sensitizer for TRAIL treatment. However, the underlying mechanism and role of celastrol in the sensitization of glioma cells remain to be elucidated. Methods The viability of glioma cell lines was examined by the CCK-8 assay. The expression of DR5 was detected by reverse transcriptase quantitative real-time PCR. The protein expression of DR5, cleaved caspase-8, cleaved caspase-3 and PARP were measured by western blot. The apoptosis rates and the sub-G1 population were detected by flow cytometry. The cellular morphological changes were assessed by TUNEL apoptosis and Hoechst 33258 staining assays. The knockdown of DR5 expression was conducted by siRNA. Results In this study, we observed that celastrol treatment inhibited cell viability in a dose-dependent manner, while glioma and normal human astroglial cell lines were resistant to TRAIL treatment. We also observed that the antiproliferative effects of TRAIL in combination with a noncytotoxic concentration of celastrol were significantly greater than those of celastrol or TRAIL alone. In addition, cell death induced by the combination treatment was apoptotic and occurred through the death receptor pathway via activation of caspase-8, caspase-3, and PARP. Furthermore, celastrol upregulated death receptor 5 (DR5) at the mRNA and protein levels, and siRNA-mediated DR5 knockdown reduced the killing effect of the combination drug treatment on glioma cells and reduced the activation of caspase-3, caspase-8 and PARP. Conclusions Taken together, the results of our study demonstrate that celastrol sensitizes glioma cells to TRAIL via the death receptor pathway and that DR5 plays an important role in the effects of this cotreatment. The results indicate that this cotreatment is a promising tumor-killing therapeutic strategy with high efficacy and low toxicity.