Cold Atmospheric Plasma Induces Accumulation of Lysosomes and Caspase-independent Cell Death in U373MG Glioblastoma Multiforme Cells

Authors

Gillian Conway, Technological University DublinFollow
Zhonglei He, Technological University Dublin
Ana L. Hutanu, Trinity College Dublin, IrelandFollow
George P. Cribaro, Universitat Autònoma de Barcelona, SpainFollow
Eline Manaloto, Technological University Dublin
Alan Casey, Technological University DublinFollow
Damien Traynor, Technological University Dublin
Vladimir Milosavljevic, Technological University DublinFollow
Orla Howe, Technological University DublinFollow
Carlos Barcia, Universitat Autonoma de Barcelona
James T. Murray, Trinity College Dublin, Ireland
Patrick Cullen, Technological University DublinFollow
James Curtin, Technological University DublinFollow

Document Type

Article

Rights

Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence

Publication Details

Scientific Reports | (2019) 9:12891 | https://doi.org/10.1038/s41598-019-49013-3

Abstract

Room temperature Cold Atmospheric Plasma (CAP) has shown promising efficacy for the treatment of cancer but the exact mechanisms of action remain unclear. Both apoptosis and necrosis have been implicated as the mode of cell death in various cancer cells. We have previously demonstrated a caspase-independent mechanism of cell death in p53-mutated glioblastoma multiforme (GBM) cells exposed to plasma. The purpose of this study was to elucidate the molecular mechanisms involved in caspase-independent cell death induced by plasma treatment. We demonstrate that plasma induces rapid cell death in GBM cells, independent of caspases. Accumulation of vesicles was observed in plasma treated cells that stained positive with acridine orange. Western immunoblotting confirmed that autophagy is not activated following plasma treatment. Acridine orange intensity correlates closely with the lysosomal marker Lyso TrackerTM Deep Red. Further investigation using isosurface visualisation of confocal imaging confirmed that lysosomal accumulation occurs in plasma treated cells. The accumulation of lysosomes was associated with concomitant cell death following plasma treatment. In conclusion, we observed rapid accumulation of acidic vesicles and cell death following CAP treatment in GBM cells. We found no evidence that either apoptosis or autophagy, however, determined that a rapid accumulation of late stage endosomes/lysosomes precedes membrane permeabilisation, mitochondrial membrane depolarisation and caspase independent cell death.

DOI

https://doi.org/10.1038/s41598-019-49013-3

Recommended Citation

Conway G. et al. Cold Atmospheric Plasma induces accumulation of lysosomes and caspase-independent cell death in U373MG glioblastoma multiforme cells. Scientific Reports 9, Article number: 12891 (2019). doi:10.1038/s41598-019-49013-3

Funder

This work is supported by Irish Research Council IRCSET grant (G.E.C.), DIT Fiosraigh Research Scholarship programme (Z.H., E.M.), Science Foundation Ireland Grant Number 11/PI/08 (A.C.), Science Foundation Ireland Grant Number 14/IA/2626 (V.M., P.C. and J.C.), Spanish Ministry of Economy and Competitiveness and European Regional Development Fund Grant number SAF2015-64123-P (C.B. and G.P.C.). The authors also thank the FOCAS Research Institute, TU Dublin and Institut de Neurociències at UAB for the use of facilities.