An extra allele of Chk1 limits oncogene-induced replicative stress and promotes transformation

Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), E-28029 Madrid, Spain.
Journal of Experimental Medicine (Impact Factor: 12.52). 02/2012; 209(3):455-61. DOI: 10.1084/jem.20112147
Source: PubMed


Replicative stress (RS) is a type of endogenous DNA damage that cells suffer every time they duplicate their genomes, and which is further boosted by oncogenes. In mammals, the RS response (RSR) is coordinated by ATR and Chk1 kinases. We sought to develop a mammalian organism that is selectively protected from RS. To this end, mice carrying an extra copy of the Chk1 gene were generated. In vitro, Chk1 transgenic cells are protected from RS-inducing agents. Moreover, an extra Chk1 allele prolongs the survival of ATR-Seckel mice, which suffer from high levels of RS, but not that of ATM-deficient mice, which accumulate DNA breaks. Surprisingly, increased Chk1 levels favor transformation, which we show is associated with a reduction in the levels of RS induced by oncogenes. Our study provides the first example where supra-physiological levels of a tumor suppressor can promote malignant transformation, which is a result of the protection from the RS found in cancer cells.

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Available from: Oskar Fdez-Capetillo, Oct 05, 2015
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    • "Cells were allowed to recover for 15 minutes prior to processing for immunofluorescence. Analysis of RPA foci was performed using an Opera High-Content Screening system as described (Lopez-Contreras et al., 2012). Primary antibodies for immunofluorescence were rabbit anti-53BP1 (Novus), mouse anti-γ-H2AX (Upstate Biotechnology), mouse or rabbit anti-FLAG-M2 (Sigma), mouse anti-AIM1 (Becton Dickinson), mouse anti-GFP (Roche), rabbit anti-RAD51 (Santa Cruz), rat anti-RPA (Cell Signaling), rabbit-anti-PTIP (Cho et al., 2009) and rabbit-anti- RIF1(Di Virgilio et al., 2013). "
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