RRC ID 64113
Author Shi L, Ito F, Wang Y, Okazaki Y, Tanaka H, Mizuno M, Hori M, Hirayama T, Nagasawa H, Richardson DR, Toyokuni S.
Title Non-thermal plasma induces a stress response in mesothelioma cells resulting in increased endocytosis, lysosome biogenesis and autophagy.
Journal Free Radic Biol Med
Abstract Non-thermal plasma (NTP) is a potential new therapeutic modality for cancer. However, its mechanism of action remains unclear. Herein, we studied the effect of NTP on mesothelioma cells and fibroblasts to understand its anti-proliferative efficacy. Interestingly, NTP demonstrated greater selective anti-proliferative activity against mesothelioma cells relative to fibroblasts than cisplatin, which is used for mesothelioma treatment. The anti-proliferative effect of NTP was enhanced by pre-incubation with the cellular iron donor, ferric ammonium citrate (FAC), and inhibited by iron chelation using desferrioxamine (DFO). Three oxidative stress probes (CM-H2DCFDA, MitoSOX and C11-BODIPY) demonstrated reactive oxygen species (ROS) generation by NTP, which was inhibited by DFO. Moreover, NTP decreased transferrin receptor-1 and increased ferritin-H and -L chain expression that was correlated with decreased iron-regulatory protein expression and RNA-binding activity. This regulation was potentially due to increased intracellular iron in lysosomes, which was demonstrated via the Fe(II)-selective probe, HMRhoNox-M, and was consistent with autophagic-induction. Immunofluorescence using LysoTracker and Pepstatin A probes demonstrated increased cellular lysosome content, which was confirmed by elevated LAMP1 expression. The enhanced lysosomal biogenesis after NTP could be due to the observed increase in fluid-phase endocytosis and early endosome formation. These results suggest NTP acts as a stressor, which results in increased endocytosis, lysosome content and autophagy. In fact, NTP rapidly increased autophagosome formation, as judged by increased LC3B-II expression, which co-localized with LAMP1, indicating autophagolysosome formation. Autophagic-induction by NTP was confirmed using electron microscopy. In summary, NTP acts as a cellular stressor to rapidly induce fluid-phase endocytosis, lysosome biogenesis and autophagy.
Volume 108
Pages 904-917
Published 2017-7-1
DOI 10.1016/j.freeradbiomed.2017.04.368
PII S0891-5849(17)30571-3
PMID 28465262
MeSH Autophagy Cell Line, Tumor Cell Proliferation Cisplatin / pharmacology Cisplatin / therapeutic use Deferoxamine / pharmacology Endocytosis Ferric Compounds / pharmacology Fibroblasts / drug effects Fibroblasts / physiology* Humans Iron / metabolism* Lysosomes / metabolism* Mesothelioma / metabolism Mesothelioma / therapy* Oxidative Stress Plasma Gases / pharmacology* Quaternary Ammonium Compounds / pharmacology Reactive Oxygen Species / metabolism
IF 6.17
Human and Animal Cells IMR-90-SV(RCB1024) Rat-1(RCB1830)