Calpain and Reactive Oxygen Species Targets Bax for Mitochondrial Permeabilisation and Caspase Activation in Zerumbone Induced Apoptosis

Abstract

Fluorescent protein based signaling probes are emerging as valuable tools to study cell signaling because of their ability to provide spatio- temporal information in non invasive live cell mode. Previously, multiple fluorescent protein probes were employed to characterize key events of apoptosis in diverse experimental systems. We have employed a live cell image based approach to visualize the key events of apoptosis signaling induced by zerumbone, the active principle from ginger Zingiber zerumbet, in cancer cells that enabled us to analyze prominent apoptotic changes in a hierarchical manner with temporal resolution. Our studies substantiate that mitochondrial permeabilisation and cytochrome c dependent caspase activation dominate in zerumbone induced cell death. Bax activation, the essential and early event of cell death, is independently activated by reactive oxygen species as well as calpains. Zerumbone failed to induce apoptosis or mitochondrial permeabilisation in Bax knockout cells and over-expression of Bax enhanced cell death induced by zerumbone confirming the essential role of Bax for mitochondrial permeabilsation. Simultaneous inhibition of reactive oxygen species and calpain is required for preventing Bax activation and cell death. However, apoptosis induced by zerumbone was prevented in Bcl 2 and Bcl-XL over-expressing cells, whereas more protection was afforded by Bcl 2 specifically targeted to endoplasmic reticulum. Even though zerumbone treatment down-regulated survival proteins such as XIAP, Survivin and Akt, it failed to affect the pro-apoptotic proteins such as PUMA and BIM. Multiple normal diploid cell lines were employed to address cytotoxic activity of zerumbone and, in general, mammary epithelial cells, endothelial progenitor cells and smooth muscle cells were relatively resistant to zerumbone induced cell death with lesser ROS accumulation than cancer cells.

Role of Activating Transcription Factor 3 (ATF3) in Endoplasmic Reticulum (ER) Stress-induced Sensitization of p53-deficient Human Colon Cancer Cells to Tumor Necrosis Factor (TNF)-related Apoptosis-inducing Ligand (TRAIL)-mediated Apoptosis through Up-regulation of Death Receptor 5 (DR5) by Zerumbone and Celecoxib

“…This study also showed that ZER-induced DR5 expression was abolished by ROS scavengers, consistent with a previous report (30,53,54). More recently, it has been reported that ZER induces cellular proteostress through its binding to cellular proteins to activate the ubiquitin-proteasome system or heat shock response (36,37).…”

Levistolide A Induces Apoptosis via ROS-Mediated ER Stress Pathway in Colon Cancer Cells

“…Therefore, targeting ROS is an important anticancer therapeutic strategy. In fact, a large number of studies have demonstrated the induction of ROS-mediated apoptosis by various therapeutic drugs [19-21]. In this study, we found that LA triggered ROS generation (Fig.…”

PPARγ Alleviates Right Ventricular Failure Secondary to Pulmonary Arterial Hypertension in Rats

“…However, PPARγ pretreatment decreased TUNEL positive cells (Figure 2A). The Bcl-2-associated X protein (Bax) is a very important pro-apoptotic protein, which plays important roles in triggering the mitochondrial death cascade, [22][23][24] and PPARγ pretreatment suppressed the over-expression of Bax in our experiment. PPARγ decreases RV inflammation in RVF rats: Inflammation plays an important role in heart failure.…”