Chang Hong-Tai, Chou Chiang-Ting, Chen I-Shu, Yu Chia-Cheng, Lu Ti, Hsu Shu-Shong, Shieh Pochuen, Jan Chung-Ren, Liang Wei-Zhe
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan, ROC.
Department of Nursing, Division of Basic Medical Sciences, Chang Gung University of Science and Technology, Chia-Yi 613, Taiwan, ROC; Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chia-Yi 613, Taiwan, ROC.
Toxicology. 2016 Aug 31;370:1-19. doi: 10.1016/j.tox.2016.09.006. Epub 2016 Oct 1.
Cytochalasin B, a cell-permeable mycotoxin isolated from the fungus Phoma spp., shows a wide range of biological effects, among which its potent antitumor activity has raised great interests in different models. However, the cytotoxic activity of cytochalasin B and its underlying mechanisms have not been elucidated in breast cells. This study examined the effect of cytochalasin B on MCF 10A human breast epithelial cells and ZR-75-1 human breast cancer cells. Cytochalasin B (10-20μM) concentration-dependently induced cytotoxicity, cell cycle arrest, and [Ca] rises in ZR-75-1 cells but not in MCF 10A cells. In ZR-75-1 cells, cytochalasin B triggered G2/M phase arrest through the modulation of CDK1, cyclin B1, p53, p27 and p21 expressions. The Ca signal response induced by cytochalasin B was reduced by removing extracellular Ca and was inhibited by the store-operated Ca channel blocker 2-APB and SKF96365. In Ca-free medium, cytochalasin B induced Ca release through thapsigargin-sensitive endoplasmic reticulum stores. Moreover, cytochalasin B increased HO levels but reduced GSH levels. The apoptotic effects evoked by cytochalasin B were partially inhibited by prechelating cytosolic Ca with BAPTA-AM and the antioxidant NAC. Together, in ZR-75-1 cells but not in MCF 10A cells, cytochalasin B activated Ca-associated mitochondrial apoptotic pathways that involved G2/M phase arrest and ROS signaling. Furthermore, cytochalasin B induced [Ca] rises by releasing Ca from the endoplasmic reticulum and causing Ca influx through 2-APB or SKF96365-sensitive store-operated Ca entry. Our findings provide new insights into the possible application of cytochalasin B in human breast cancer therapy.
细胞松弛素B是一种可透过细胞的霉菌毒素，从茎点霉属真菌中分离得到，具有广泛的生物学效应，其中其强大的抗肿瘤活性在不同模型中引起了极大关注。然而，细胞松弛素B在乳腺细胞中的细胞毒性活性及其潜在机制尚未阐明。本研究检测了细胞松弛素B对MCF 10A人乳腺上皮细胞和ZR-75-1人乳腺癌细胞的影响。细胞松弛素B（10-20μM）浓度依赖性地诱导ZR-75-1细胞的细胞毒性、细胞周期停滞和[Ca]升高，但对MCF 10A细胞无此作用。在ZR-75-1细胞中，细胞松弛素B通过调节CDK1、细胞周期蛋白B1、p53、p27和p21的表达触发G2/M期停滞。去除细胞外Ca可降低细胞松弛素B诱导的Ca信号反应，而储存-操纵性Ca通道阻滞剂2-APB和SKF96365可抑制该反应。在无Ca培养基中，细胞松弛素B通过毒胡萝卜素敏感的内质网储存诱导Ca释放。此外，细胞松弛素B增加了HO水平，但降低了GSH水平。用BAPTA-AM和抗氧化剂NAC预先螯合胞质Ca可部分抑制细胞松弛素B诱发的凋亡效应。总之，在ZR-75-1细胞而非MCF 10A细胞中，细胞松弛素B激活了与Ca相关的线粒体凋亡途径，该途径涉及G2/M期停滞和ROS信号传导。此外，细胞松弛素B通过从内质网释放Ca并通过2-APB或SKF96365敏感的储存-操纵性Ca内流引起Ca内流来诱导[Ca]升高。我们的研究结果为细胞松弛素B在人类乳腺癌治疗中的可能应用提供了新的见解。
