First Author | Hoogervorst EM | Year | 2005 |
Journal | DNA Repair (Amst) | Volume | 4 |
Issue | 1 | Pages | 3-9 |
PubMed ID | 15533832 | Mgi Jnum | J:94445 |
Mgi Id | MGI:3512821 | Doi | 10.1016/j.dnarep.2004.08.009 |
Citation | Hoogervorst EM, et al. (2005) 2-AAF-induced tumor development in nucleotide excision repair-deficient mice is associated with a defect in global genome repair but not with transcription coupled repair. DNA Repair (Amst) 4(1):3-9 |
abstractText | The nucleotide excision repair (NER) pathway comprises two sub-pathways, transcription coupled repair (TCR) and global genome repair (GGR). To establish the importance of these separate sub-pathways in tumor suppression, we exposed mice deficient for either TCR (Csb), GGR (Xpc) or both (Xpa) to 300 ppm 2-acetylaminofluorene (in feed, ad libitum) in a unique comparative exposure experiment. We found that cancer proneness was directly linked to a defect in the GGR pathway of NER as both Xpa and Xpc mice developed significantly more liver tumors upon 2-AAF exposure than wild type or Csb mice. In contrast, a defect in TCR appeared to act tumor suppressive, leading to a lower hepatocellular tumor response in Xpa mice (tumor incidence of 25%) as compared to Xpc mice (53% tumor-bearing mice). The link between deficient GGR and tumor proneness was most pronounced in the liver, but this phenomenon was also found in the urinary bladder. As tumor induction by 2-AAF appeared almost exclusively dependent on a defect in GGR, we examined whether gene mutation induction in the non-transcribed lacZ locus could reliably predict tumor risk. Interestingly, however, short-term 2-AAF exposure induced lacZ mutant levels in Csb mice almost as high as those found in Xpa or Xpc mice. This indicates that lacZ mutant frequencies are not correlated with a specific DNA repair defect and eventual tumor outcome, at least not in the experimental design presented here. |