Open AccessEpigallocatechin‐3‐gallate induces mesothelioma cell death via H 2 O 2 −dependent T‐type Ca 2+ channel opening
Author(s) -
Ranzato Elia,
Martinotti Simona,
Magnelli Valeria,
Murer Bruno,
Biffo Stefano,
Mutti Luciano,
Burlando Bruno
Publication year - 2012
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2012.01584.x
Subject(s) - cytotoxicity , apoptosis , microbiology and biotechnology , chemistry , dithiothreitol , mibefradil , programmed cell death , necrosis , cancer research , in vitro , biochemistry , biology , calcium , pathology , voltage dependent calcium channel , medicine , enzyme , organic chemistry
Malignant mesothelioma ( MMe ) is a highly aggressive, lethal tumour requiring the development of more effective therapies. The green tea polyphenol epigallocathechin‐3‐gallate ( EGCG ) inhibits the growth of many types of cancer cells. We found that EGCG is selectively cytotoxic to MM e cells with respect to normal mesothelial cells. MM e cell viability was inhibited by predominant induction of apoptosis at lower doses and necrosis at higher doses. EGCG elicited H 2 O 2 release in cell cultures, and exogenous catalase ( CAT ) abrogated EGCG ‐induced cytotoxicity, apoptosis and necrosis. Confocal imaging of fluo 3‐loaded, EGCG ‐exposed MM e cells showed significant [Ca 2+ ] i rise, prevented by CAT , dithiothreitol or the T‐type Ca 2+ channel blockers mibefradil and NiCl 2 . Cell loading with dihydrorhodamine 123 revealed EGCG ‐induced ROS production, prevented by CAT , mibefradil or the Ca 2+ chelator BAPTA ‐ AM . Direct exposure of cells to H 2 O 2 produced similar effects on Ca 2+ and ROS , and these effects were prevented by the same inhibitors. Sensitivity of REN cells to EGCG was correlated with higher expression of Ca v 3.2 T‐type Ca 2+ channels in these cells, compared to normal mesothelium. Also, Ca v 3.2 si RNA on MM e cells reduced in vitro EGCG cytotoxicity and abated apoptosis and necrosis. Intriguingly, Ca v 3.2 expression was observed in malignant pleural mesothelioma biopsies from patients, but not in normal pleura. In conclusion, data showed the expression of T‐type Ca 2+ channels in MM e tissue and their role in EGCG selective cytotoxicity to MM e cells, suggesting the possible use of these channels as a novel MM e pharmacological target.