Short interfering RNA-mediated silencing of glutaredoxin 2 increases the sensitivity of HeLa cells toward doxorubicin and phenylarsine oxide.
Glutaredoxin (Grx) belongs to the thioredoxin fold superfamily and catalyzes glutathione-dependent oxidoreductions. The recently discovered mitochondrial and nuclear Grx (Grx2) differs from the more abundant cytosolic Grx (Grx1) by its higher affinity toward S-glutathionylated proteins and by being a substrate for thioredoxin reductase. Here, we have successfully established a method to silence the expression of Grx2 in HeLa cells by using short interfering RNA to study its role in the cell. Cells with levels of Grx2 <3% of the control were dramatically sensitized to cell death induced by doxorubicin/adriamycin and phenylarsine oxide but did not show signs of a general increase in oxidative damage with respect to carbonylation and glutathionylation. The ED(50) for doxorubicin dropped from 40 to 0.7 microM and for phenylarsine oxide from 200 to 5 nM. However, no differences were detected after treatment with cadmium, a known inhibitor of Grx1. These results indicate a crucial role of Grx2 in the regulation of the mitochondrial redox status and regulation of cell death at the mitochondrial checkpoint.
Medical Nobel Institute for Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institute, SE-17177 Stockholm, Sweden.
Christopher Horst
CH
Lillig
Maria Elisabet
ME
Lönn
Mari
M
Enoksson
Aristi Potamitou
AP
Fernandes
Arne
A
Holmgren
D001152:Arsenicals / Q000494:pharmacology*; D002104:Cadmium / Q000494:pharmacology; D004317:Doxorubicin / Q000494:pharmacology*; D020868:Gene Silencing; D054477:Glutaredoxins; D006367:HeLa Cells; D006801:Humans; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000037:antagonists & inhibitors* / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology*
D001152:Arsenicals; C516005:GLRX protein, human; C516008:GLRX2 protein, human; D054477:Glutaredoxins; D034741:RNA, Small Interfering; D002104:Cadmium; C029341:oxophenylarsine; D004317:Doxorubicin; D010088:Oxidoreductases