Pardaxin Activates Excessive Mitophagy and Mitochondria-Mediated Apoptosis in Human Ovarian Cancer by Inducing Reactive Oxygen Species

Abstract

Most ovarian cancer (OC) patients are diagnosed with stage III or higher disease, resulting in a poor prognosis. Currently, paclitaxel combined with carboplatin shows the best treatment outcome for OC. However, no effective drug is available for patients that do not respond to treatment; thus, new drugs for OC are needed. We evaluated the antimicrobial peptide, pardaxin, in PA-1 and SKOV3 cells. Pardaxin induced apoptosis as determined by MTT and TUNEL assays, as well as activation of caspases-9/3, Bid, t-Bid, and Bax, whereas Bcl-2 was downregulated. The IC50 values for pardaxin were 4.6–3.0 μM at 24 and 48 h. Mitochondrial and intracellular reactive oxygen species (ROS) were overproduced and associated with disrupted mitochondrial membrane potential and respiratory capacity. Additionally, the mitochondrial network was fragmented with downregulated fusogenic proteins, MFN1/2 and L-/S-OPA1, and upregulated fission-related proteins, DRP1 and FIS1. Autophagy was also activated as evidenced by increased expression of autophagosome formation-related proteins, Beclin, p62, and LC3. Enhanced mitochondrial fragmentation and autophagy indicate that mitophagy was activated. ROS-induced cytotoxicity was reversed by the addition of N-acetylcysteine, confirming ROS overproduction as a contributor. Taken together, pardaxin demonstrated promising anticancer activity in OC cells, which warrants further preclinical development of this compound.

Parkin, as a Regulator, Participates in Arsenic Trioxide-Triggered Mitophagy in HeLa Cells

“…Previous studies indicated that the PINK1/Parkin pathway was widely accepted as the chief mechanism of mitophagy, closely related to the regulation of mitochondrial membrane potential, mitochondrial fusion/fission and mitochondrial function [ 27 ]. Narendra et al demonstrated that Parkin is selectively recruited to dysfunctional mitochondria in mammalian cells and that after recruitment, Parkin mediates the engulfment of mitochondria by autophagosomes and their subsequent degradation [ 7 ].…”

Lycium Barbarum polysaccharide protects HaCaT cells from PM2.5-induced apoptosis via inhibiting oxidative stress, ER stress and autophagy

“…To further study how autophagy induced by PM2.5 leads to apoptosis, we have further studied a special form of autophagy, mitophagy. Mitophagy is a cellular metabolic process, the role of which is to recover damaged mitochondria and maintain cell physiological functions [ 41 ], but continuous mitophagy may aggravate mitochondrial damage and induce cell apoptosis [ 42 , 43 ]. In this study, the fusion (yellow puncta) of mitochondria and autophagosomes is obviously observed in the cells treated with PM2.5, indicating that PM2.5 induces mitophagy in HaCaT cells ( Figure 8 (A)).…”

Sinularin Induces Oxidative Stress-Mediated Apoptosis and Mitochondrial Dysfunction, and Inhibits Angiogenesis in Glioblastoma Cells

“…A number of cells (6 × 10 4 ) were then transferred to a 5 mL culture tube. All samples were processed for Annexin V label according to the literature [ 17 , 18 ]. At the end of the incubation, 1 mL of 1× binding buffer was added to each sample and the sample was analyzed using a flow cytometer Beckman Coulter cytometer (Beckman-Coulter, Brea, MI, USA) with the use of Cell Lab Quanta™ SC analysis software.…”

“…CellROX ® Green Reagent was applied to measure oxidative stress in live cells. The procedures for each staining method were conducted as described in the literature [ 17 ]. The fluorescence yielded from the staining reagents was detected using a Beckman Coulter cytometer (Beckman-Coulter, MI, USA) with the use of Cell Lab QuantaTM SC analysis software.…”