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Enhanced sensitivity to hydrogen peroxide‐induced apoptosis in Evi1 transformed Rat1 fibroblasts due to repression of carbonic anhydrase III
Author(s) -
Roy P.,
Reavey E.,
Rayne M.,
Roy S.,
Abed El Baky M.,
Ishii Y.,
Bartholomew C.
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.07496.x
Subject(s) - hydrogen peroxide , carbonic anhydrase , psychological repression , chemistry , carbonic anhydrase ii , apoptosis , microbiology and biotechnology , enzyme , biochemistry , biology , gene expression , gene
EVI1 is a nuclear zinc finger protein essential to normal development, which participates in acute myeloid leukaemia progression and transforms Rat1 fibroblasts. In this study we show that enforced expression of Evi1 in Rat1 fibroblasts protects from paclitaxel‐induced apoptosis, consistent with previously published studies. Surprisingly, however, these cells show increased sensitivity to hydrogen peroxide (H 2 O 2 )‐induced apoptosis, demonstrated by elevated caspase 3 catalytic activity. This effect is caused by a reduction in carbonic anhydrase III (caIII) production. ca III transcripts are repressed by 92–97% by Evi1 expression, accompanied by a similar reduction in caIII protein. Reporter assays with the rat ca III gene promoter show repressed activity, demonstrating that Evi1 either directly or indirectly modulates transcription of this gene in Rat1 cells. Targeted knockdown of ca III alone, with Dicer‐substrate short inhibitory RNAs, also increases the sensitivity of Rat1 fibroblasts to H 2 O 2 , which occurs in the absence of any other changes mediated by Evi1 expression. Enforced expression of ca III in Evi 1‐expressing Rat1 cells reverts the phenotype, restoring H 2 O 2 resistance. Together these data show that Evi1 represses transcription of ca III gene expression, leading to increased sensitivity to H 2 O 2 ‐induced apoptosis in Rat1 cells and might suggest the basis for the development of a novel therapeutic strategy for the treatment of leukaemias and solid tumours where EVI1 is overexpressed.