Wang Alice T, Prinsep Michèle R, Martinus Ryan D
School of Science, Faculty of Science and Engineering, The University of Waikato, Hamilton, New Zealand.
Springerplus. 2016 Jun 16;5(1):742. doi: 10.1186/s40064-016-2397-9. eCollection 2016.
Pterocellin A is a novel bioactive alkaloid isolated from the New Zealand marine bryozoan Pterocella vesiculosa. It exhibits potent antitumour activity towards the P388 (murine leukaemia) cell line in vitro and is selectively sensitive towards certain non-small cell lung, melanoma, and breast cancer cell lines, however, the biological mode of action of pterocellin A is unknown. Using the human cervical cancer cell line HeLa, we show that pterocellin A exhibited cytotoxicity against HeLa cells with an IC50 of 886 ng/mL. Time-course MTT and LDH assays were carried out and the results showed only a low level of cytosolic LDH was detected in the supernatant after all the cells have died from pterocellin A treatment at 2000 ng/mL. This indicated the cells maintained membrane integrity upon cell death which suggested apoptotic cell death. Additionally, morphological changes were observed under the microscope after 6 h of treatment. Cell shrinkage and nucleus condensation were observed, as well as apparent membrane blebbing, a key feature of apoptosis. The MTT data was also indicative of mitochondria impairment which could suggest that pterocellin A targets the mitochondria. This idea was supported by the observed changes in the morphology and location of the mitochondria after exposure to pterocellin A. Furthermore, the level of activated caspase-3 in HeLa cells increased after treatment with pterocellin A; activated caspase-3 can only be detected after a series of signalling events following the induction of apoptosis. These data support the notion that pterocellin A is an inducer of apoptosis in HeLa cells possibly via mitochondria related processes.
翼苔藓虫素A是一种从新西兰海洋苔藓虫泡状翼苔藓虫中分离出的新型生物活性生物碱。它在体外对P388（小鼠白血病）细胞系表现出强大的抗肿瘤活性，并且对某些非小细胞肺癌、黑色素瘤和乳腺癌细胞系具有选择性敏感性，然而，翼苔藓虫素A的生物学作用模式尚不清楚。使用人宫颈癌细胞系HeLa，我们发现翼苔藓虫素A对HeLa细胞具有细胞毒性，IC50为886 ng/mL。进行了时间进程MTT和LDH测定，结果显示在所有细胞因2000 ng/mL的翼苔藓虫素A处理而死亡后，上清液中仅检测到低水平的胞质LDH。这表明细胞在死亡时保持膜完整性，提示细胞凋亡死亡。此外，处理6小时后在显微镜下观察到形态变化。观察到细胞收缩和核浓缩，以及明显的膜泡形成，这是细胞凋亡的一个关键特征。MTT数据也表明线粒体受损，这可能表明翼苔藓虫素A靶向线粒体。暴露于翼苔藓虫素A后观察到的线粒体形态和位置变化支持了这一观点。此外，用翼苔藓虫素A处理后，HeLa细胞中活化的半胱天冬酶-3水平升高；活化的半胱天冬酶-3只有在凋亡诱导后的一系列信号事件后才能检测到。这些数据支持了翼苔藓虫素A可能通过与线粒体相关的过程诱导HeLa细胞凋亡的观点。
