@article{ThierbachBlumeWolfrumetal.2010, author = {Thierbach, Ren{\´e} and Blume, Urte and Wolfrum, K. and Drewes, Gunnar and Voigt, Anja and Ristow, Michael and Steinberg, Pablo}, title = {Altered carbohydrate metabolism in a tumour developing knock-out mice model}, issn = {0028-1298}, doi = {10.1007/s00210-010-0508-7}, year = {2010}, language = {en} } @article{ThierbachFlorianWolfrumetal.2012, author = {Thierbach, Rene and Florian, Simone and Wolfrum, Katharina and Voigt, Anja and Drewes, Gunnar and Blume, Urte and Bannasch, Peter and Ristow, Michael and Steinberg, Pablo}, title = {Specific alterations of carbohydrate metabolism are associated with hepatocarcinogenesis in mitochondrially impaired mice}, series = {Human molecular genetics}, volume = {21}, journal = {Human molecular genetics}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0964-6906}, doi = {10.1093/hmg/ddr499}, pages = {656 -- 663}, year = {2012}, abstract = {Friedreich's ataxia is an inherited neurodegenerative disease caused by the reduced expression of the mitochondrially active protein frataxin. We have previously shown that mice with a hepatocyte-specific frataxin knockout (AlbFxn(-/-)) develop multiple hepatic tumors in later life. In the present study, hepatic carbohydrate metabolism in AlbFxn(-/-) mice at an early and late life stage was analyzed. In young (5-week-old) AlbFxn(-/-) mice hepatic ATP, glucose-6-phosphate and glycogen levels were found to be reduced by similar to 74, 80 and 88\%, respectively, when compared with control animals. This pronounced ATP, G6P and glycogen depletion in the livers of young mice reverted in older animals: while half of the mice die before 30 weeks of age, the other half reaches 17 months of age and exhibits glycogen, G6P and ATP levels similar to those in age-matched controls. A key event in this respect seems to be the up-regulation of GLUT1, the predominant glucose transporter in fetal liver parenchyma, which became evident in AlbFxn(-/-) mice being 5-12 weeks of age. The most significant histological findings in animals being 17 or 22 months of age were the appearance of multiple clear cell, mixed cell and basophilic foci throughout the liver parenchyma as well as the development of hepatocellular adenomas and carcinomas. The hepatocarcinogenic process in AlbFxn 2/2 mice shows remarkable differences regarding carbohydrate metabolism alterations when compared with all other chemically and virally driven liver cancer models described up to now.}, language = {en} } @article{ThierbachDrewesFusseretal.2010, author = {Thierbach, Ren{\´e} and Drewes, Gunnar and Fusser, Markus and Voigt, Anja and Kuhlow, Doreen and Blume, Urte and Schulz, Tim Julius and Reiche, Carina and Glatt, Hansruedi and Epe, Bernd and Steinberg, Pablo and Ristow, Michael}, title = {The Friedreich's ataxia protein frataxin modulates DNA base excision repair in prokaryotes and mammals}, issn = {0264-6021}, doi = {10.1042/Bj20101116}, year = {2010}, abstract = {DNA-repair mechanisms enable cells to maintain their genetic information by protecting it from mutations that may cause malignant growth. Recent evidence suggests that specific DNA-repair enzymes contain ISCs (iron-sulfur clusters). The nuclear-encoded protein frataxin is essential for the mitochondrial biosynthesis of ISCs. Frataxin deficiency causes a neurodegenerative disorder named Friedreich's ataxia in humans. Various types of cancer occurring at young age are associated with this disease, and hence with frataxin deficiency. Mice carrying a hepatocyte- specific disruption of the frataxin gene develop multiple liver tumours for unresolved reasons. In the present study, we show that frataxin deficiency in murine liver is associated with increased basal levels of oxidative DNA base damage. Accordingly, eukaryotic V79 fibroblasts overexpressing human frataxin show decreased basal levels of these modifications, while prokaryotic Salmonella enterica serotype Typhimurium TA 104 strains transformed with human frataxin show decreased mutation rates. The repair rates of oxidative DNA base modifications in V79 cells overexpressing frataxin were significantly higher than in control cells. Lastly, cleavage activity related to the ISC-independent repair enzyme 8-oxoguanine glycosylase was found to be unaltered by frataxin overexpression. These findings indicate that frataxin modulates DNA-repair mechanisms probably due to its impact on ISC-dependent repair proteins, linking mitochondrial dysfunction to DNA repair and tumour initiation.}, language = {en} }