@article{ThierbachSchulzVoigtetal.2004, author = {Thierbach, Rene and Schulz, Tim Julius and Voigt, Aanja and Drewes, Gunnar and Isken, F. and Pfeiffer, Andreas F. H. and Ristow, Michael and Steinberg, Pablo}, title = {Targeted disruption of frataxin in hepatocytes causes spontaneous neoplasia accompanied by increased ROS formation}, issn = {0028-1298}, year = {2004}, language = {en} } @article{SchulzThierbachVoigtetal.2006, author = {Schulz, Tim Julius and Thierbach, Ren{\`e} and Voigt, Anja and Drewes, Gunnar and Mietzner, Brun and Steinberg, Pablo and Pfeiffer, Andreas F. H. and Ristow, Michael}, title = {Induction of oxidative metabolism by mitochondrial frataxin inhibits cancer growth : Otto Warburg revisited}, doi = {10.1074/jbc.M511064200}, year = {2006}, abstract = {More than 80 years ago Otto Warburg suggested that cancer might be caused by a decrease in mitochondrial energy metabolism paralleled by an increase in glycolytic flux. In later years, it was shown that cancer cells exhibit multiple alterations in mitochondrial content, structure, function, and activity. We have stably overexpressed the Friedreich ataxia-associated protein frataxin in several colon cancer cell lines. These cells have increased oxidative metabolism, as shown by concurrent increases in aconitase activity, mitochondrial membrane potential, cellular respiration, and ATP content. Consistent with Warburg's hypothesis, we found that frataxin-overexpressing cells also have decreased growth rates and increased population doubling times, show inhibited colony formation capacity in soft agar assays, and exhibit a reduced capacity for tumor formation when injected into nude mice. Furthermore, overexpression of frataxin leads to an increased phosphorylation of the tumor suppressor p38 mitogen-activated protein kinase, as well as decreased phosphorylation of extracellular signal-regulated kinase. Taken together, these results support the view that an increase in oxidative metabolism induced by mitochondrial frataxin may inhibit cancer growth in mammals}, language = {en} } @article{ThierbachSchulzIskenetal.2005, author = {Thierbach, Ren{\`e} and Schulz, Tim Julius and Isken, Frank and Voigt, Aanja and Mietzner, Brun and Drewes, Gunnar and von Kleist-Retzow, J{\"u}rgen-Christoph and Wiesner, Rudolf J. and Magnuson, Mark A. and Puccio, Helene and Pfeiffer, Andreas F. H. and Steinberg, Pablo and Ristow, Michael}, title = {Targeted disruption of hepatic frataxin expression causes impaired mitochondrial function, decreased life span and tumor growth in mice}, year = {2005}, abstract = {We have disrupted expression of the mitochondrial Friedreich ataxia protein frataxin specifically in murine hepatocytes to generate mice with impaired mitochondrial function and decreased oxidative phosphorylation. These animals have a reduced life span and develop multiple hepatic tumors. Livers also show increased oxidative stress, impaired respiration and reduced ATP levels paralleled by reduced activity of iron-sulfur cluster (Fe/S) containing proteins (ISP), which all leads to increased hepatocyte turnover by promoting both apoptosis and proliferation. Accordingly, phosphorylation of the stress-inducible p38 MAP kinase was found to be specifically impaired following disruption of frataxin. Taken together, these findings indicate that frataxin may act as a mitochondrial tumor suppressor protein in mammals}, language = {en} }