Palanivel Kandasamy, Kanimozhi Veerasamy, Kadalmani Balamuthu, Akbarsha Mohammad Abdulkader
Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India.
J Cell Biochem. 2014 Nov;115(11):2022-32. doi: 10.1002/jcb.24874.
The present study was carried out to elucidate the mechanisms underlying Verrucarin A (VA)-induced cytotoxicity in human breast cancer cell line MDA-MB-231. VA inhibited the growth of MDA-MB-231 cells by induction of reactive oxygen species (ROS)-dependent mitochondrial apoptosis. Elevation of ROS production, associated with changes in Bax/Bcl-2 ratio, led to loss of mitochondrial membrane potential (Δψm) and cytochrome c release in VA-treated cells. Release of cytochrome c from mitochondria to cytosol triggered activation of caspase-3, PARP cleavage, DNA fragmentation, and finally apoptotic cell death. Furthermore, VA-induced apoptosis was accompanied by the activation of p38MAPK and inhibition of phosphorylation of EGFR as well as of Akt and ERK1/2. However, pre-treatment with n-acetyl cysteine, an ROS scavenger, and SB202190, a p38MAPK inhibitor, significantly inhibited VA-induced ROS generation, EGFR inhibition, p38MAPK activation and apoptosis. Moreover, pharmacological inhibition of EGFR and ERK1/2 significantly accelerated the VA-induced apoptosis in MDA-MB-231 cells. Collectively, these results indicate that VA-induces ROS elevation in cancer cells, which results in the activation of p38MAPK and inhibition of EGFR/Akt/ERK signaling cascade and, ultimately, cancer cell death.
本研究旨在阐明疣孢漆斑菌素A（VA）诱导人乳腺癌细胞系MDA-MB-231细胞毒性的潜在机制。VA通过诱导活性氧（ROS）依赖性线粒体凋亡来抑制MDA-MB-231细胞的生长。ROS生成增加，伴随着Bax/Bcl-2比值的变化，导致VA处理的细胞线粒体膜电位（Δψm）丧失和细胞色素c释放。细胞色素c从线粒体释放到细胞质中触发了caspase-3的激活、PARP裂解、DNA片段化，最终导致凋亡细胞死亡。此外，VA诱导的凋亡伴随着p38MAPK的激活以及EGFR、Akt和ERK1/2磷酸化的抑制。然而，用ROS清除剂N-乙酰半胱氨酸和p38MAPK抑制剂SB202190预处理可显著抑制VA诱导的ROS生成、EGFR抑制、p38MAPK激活和凋亡。此外，EGFR和ERK1/2的药理学抑制显著加速了VA诱导的MDA-MB-231细胞凋亡。总的来说，这些结果表明VA诱导癌细胞中ROS升高，这导致p38MAPK激活以及EGFR/Akt/ERK信号级联的抑制，并最终导致癌细胞死亡。
