Expression of telomerase inhibits hydroxyl radical-induced apoptosis in normal telomerase negative human lung fibroblasts

In tumor cells telomerase activity is associated with resistance to apoptos is and the introduction of the human telomerase reverse transcriptase (hTER T) subunit into normal human cells is associated with life span extension o f the cells, To determine the role of telomerase in regulating apoptosis, t elomerase negative human embryo lung fibroblasts Here transfected with the hTERT gene, Unlike the control fibroblasts, the telomerase-expressing cells had elongated telomeres and were resistant to apoptosis induced by hydroxy l radicals, The results indicate that expression of telomerase and, thus, t he maintenance of telomere length in normal human somatic cells caused resi stance to not only cellular senescence but also apoptosis. Moreover, we fou nd that hydroxyl radical-induced apoptosis in telomerase-expressing and con trol fibroblasts was caspase-3 independent, These findings have revealed a nea type of interrelation between telomerase and caspase-3, which may indic ate that in this case the expressed telomerase may inhibit apoptosis at a s ite not related to the caspase-3 cascade, (C) 2001 Federation of European B iochemical Societies, Published bq Elsevier Science B.V. All rights reserve d.