Huang Shengshi, Wang Di, Zhang Shu, Huang Xiaoyan, Wang Dandan, Ijaz Muhammad, Shi Yikang
National Glycoengineering Research Center, Shandong University, Jinan, 250012, China.
Cancer Chemother Pharmacol. 2017 Oct;80(4):685-696. doi: 10.1007/s00280-017-3393-7. Epub 2017 Aug 4.
Paclitaxel has been reported to upregulate both AKT and MAPK signaling pathways and thereby compromises its antitumor efficacy. However, tunicamycin has the ability to downregulate AKT and MAPK pathways. The aim of the study is to investigate the antitumor activity of the combination treatment of paclitaxel with tunicamycin and the mechanisms involving the changes of antitumor efficacy.
Sulforhodamine B (SRB) assay was used to examine the cell viability upon treatment of breast cancer cells with paclitaxel, tunicamycin and the combination of both. Cell cycle distributions and apoptosis were detected by flow cytometry. Western blotting and immunofluorescence staining were used to analyze the effect of drugs on tubulin polymerization. The antitumor growth of combined treatment was measured in nude mice bearing MDA-MB-231 xenograft. Western blotting was performed to explore the alteration of AKT and MAPK pathways in vitro and in vivo.
SRB assay and nude mice experiment showed that tunicamycin synergistically enhanced paclitaxel-induced inhibition of cell proliferation and tumor growth. Tunicamycin had no clear effect on paclitaxel-induced cell cycle arrest, demonstrating that cell cycle distribution was not involved in the enhanced antitumor activity. Both annexin V-FITC/propidium iodide assay and TUNEL assay indicated that the combination of tunicamycin with paclitaxel resulted in significant increased cell apoptosis as compared with individual treatment in vitro and in vivo. Tunicamycin decreased paclitaxel-induced microtubulin polymerization, suggesting that enhanced antitumor effect of paclitaxel was not dependent of microtubulin polymerization. Western blotting analysis confirmed that tunicamycin decreased paclitaxel-induced upregulation of survival signal pathways such as AKT and MAPK.
These results revealed that tunicamycin synergistically enhanced the antitumor effects of paclitaxel through potentiating apoptosis via inhibiting paclitaxel-induced elevation of AKT and MAPK pathways. This study raised the possibility that the combination of paclitaxel with tunicamycin may be a promising approach for improving the clinical activity of paclitaxel.
据报道，紫杉醇可上调AKT和MAPK信号通路，从而削弱其抗肿瘤疗效。然而，衣霉素具有下调AKT和MAPK通路的能力。本研究的目的是探讨紫杉醇与衣霉素联合治疗的抗肿瘤活性以及涉及抗肿瘤疗效变化的机制。
采用磺酰罗丹明B（SRB）法检测紫杉醇、衣霉素及其联合处理对乳腺癌细胞活力的影响。通过流式细胞术检测细胞周期分布和凋亡情况。采用蛋白质免疫印迹法和免疫荧光染色法分析药物对微管蛋白聚合的影响。在携带MDA-MB-231异种移植瘤的裸鼠中测量联合治疗的抗肿瘤生长情况。进行蛋白质免疫印迹法以探讨体外和体内AKT和MAPK通路的变化。
SRB法和裸鼠实验表明，衣霉素协同增强了紫杉醇诱导的细胞增殖抑制和肿瘤生长抑制。衣霉素对紫杉醇诱导的细胞周期阻滞没有明显影响，表明细胞周期分布与增强的抗肿瘤活性无关。膜联蛋白V-异硫氰酸荧光素/碘化丙啶检测法和TUNEL检测法均表明，与单独治疗相比，衣霉素与紫杉醇联合使用在体外和体内均导致细胞凋亡显著增加。衣霉素降低了紫杉醇诱导的微管蛋白聚合，表明紫杉醇增强的抗肿瘤作用不依赖于微管蛋白聚合。蛋白质免疫印迹分析证实，衣霉素降低了紫杉醇诱导的生存信号通路如AKT和MAPK的上调。
这些结果表明，衣霉素通过抑制紫杉醇诱导的AKT和MAPK通路升高来增强凋亡，从而协同增强紫杉醇的抗肿瘤作用。本研究提出了紫杉醇与衣霉素联合使用可能是提高紫杉醇临床活性的一种有前景的方法的可能性。
