Oxyresveratrol activates parallel apoptotic and autophagic cell death pathways in neuroblastoma cells.
Drug resistance from apoptosis is a challenging issue with different cancer types, and there is an interest in identifying other means of inducing cytotoxicity. Here, treatment of neuroblastoma cells with oxyresveratrol (OXYRES), a natural antioxidant, led to dose-dependent cell death and increased autophagic flux along with activation of caspase-dependent apoptosis.



For cell viability, we performed the CCK-8 assay. Protein expression changes were with Western blot and immunocytochemistry. Silencing of proteins was with siRNA. The readouts for cell cycle, mitochondria membrane potential, caspase-3, autophagy and apoptosis were performed with flow cytometry.



Phosphorylation of p38 MAPK increased with OXYRES treatment and inhibition of p38 reduced autophagy and cell death from OXYRES. In contrast, PI3K/AKT/mTOR signaling decreased in the target cells with OXYRES and inhibition of PI3K or mTOR enhanced OXYRES-mediated cytotoxicity with increased levels of autophagy. Modulation of either of the apoptosis and autophagy flux pathways affected the extent of cell death by OXYRES, but did not affect the indicators of these pathways with respect to each other. Both pathways were independent of ROS generation or p53 activation.



OXYRES led to cell death from autophagy, which was independent of apoptosis induction. The OXYRES effects were due to changes in the activity levels of p38 MAPK and PI3K/AKT/mTOR.



With two independent and parallel pathways for cytotoxicity induction in target cells, this study puts forward a potential utility for OXYRES or the pathways it represents as novel means of inducing cell death in neuroblastoma cells.
Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, South Korea.
Md Ataur
MA
Rahman
Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, South Korea.
Kausik
K
Bishayee
Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, South Korea.
Ali
A
Sadra
Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, South Korea. Electronic address: s0huh@hallym.ac.kr.
Sung-Oh
SO
Huh
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D009447:Neuroblastoma / Q000188:drug therapy* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013267:Stilbenes / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3; D019869:Phosphatidylinositol 3-Kinases; D010936:Plant Extracts; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species; D013267:Stilbenes; D058570:TOR Serine-Threonine Kinases; D016159:Tumor Suppressor Protein p53; D048051:p38 Mitogen-Activated Protein Kinases; C034912:puag-haad
Caspase-independent; Macroautophagy; Neuroblastoma; Oxyresveratrol; mTOR signaling; p38 MAPK