Role of the PLA 2-independent peroxiredoxin VI activity in the survival of immortalized fibroblasts exposed to cytotoxic oxidative stress

Peroxiredoxin VI (PrxVI) is a bifunctional enzyme with non-selenium glutathione peroxidase and Ca 2+-independent acidic phospholipase A 2 activities. We demonstrate that transfection-mediated PrxVI overexpression protects immortalized human WI-38 and murine NIH3T3 fibroblasts against cytotoxic doses of tert-butylhydroperoxide and H 2O 2. Mutants for either glutathione peroxidase or phospholipase A 2 activity show that glutathione peroxidase but not phospholipase A 2 activity is required to promote cell survival after stress. Also, ectopic PrxVI overexpression does not protect telomerase-stabilized WI-38 fibroblasts against stress-induced premature senescence.