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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http://dx.doi.org/10.1084/jem.20112147 | DOI Listing |
Nat Commun
January 2025
Robson DNA Science Centre, Charbonneau Cancer Institute, Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
To tolerate oxidative stress, cells enable DNA repair responses often sensitive to poly(ADP-ribose) (PAR) polymerase 1 and 2 (PARP1/2) inhibition-an intervention effective against cancers lacking BRCA1/2. Here, we demonstrate that mutating the CHD6 chromatin remodeler sensitizes cells to PARP1/2 inhibitors in a manner distinct from BRCA1, and that CHD6 recruitment to DNA damage requires cooperation between PAR- and DNA-binding domains essential for nucleosome sliding activity. CHD6 displays direct PAR-binding, interacts with PARP-1 and other PAR-associated proteins, and combined DNA- and PAR-binding loss eliminates CHD6 relocalization to DNA damage.
View Article and Find Full Text PDFMol Divers
January 2025
Department of Laboratory Medicine, The Fourth People's Hospital of Nanhai District of Foshan City, Foshan, 528000, Guangdong, China.
Disruption of the mycobacterial redox homeostasis leads to irreversible stress induction and cell death. Hydroquinone scaffolds, as a new type of redox cycling anti-tuberculosis chemotypes, exhibit potent bactericidal activity against non-replicating, nutrient-deprived phenotypically drug-resistant bacteria. Evidences from microbiological, biochemical, and genetic studies indicate that the redox-driven mode of action relies on the reduction of quinones by type II NADH dehydrogenase (NDH2), generating reactive oxygen species (ROS) of bactericidal level.
View Article and Find Full Text PDFViruses
January 2025
Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
The betacoronavirus genus contains five of the seven human coronaviruses, making it a particularly critical area of research to prepare for future viral emergence. We utilized three human betacoronaviruses, one from each subgenus-HCoV-OC43 (embecovirus), SARS-CoV-2 (sarbecovirus), and MERS-CoV (merbecovirus)-, to study betacoronavirus interactions with the PKR-like ER kinase (PERK) pathway of the integrated stress response (ISR)/unfolded protein response (UPR). The PERK pathway becomes activated by an abundance of unfolded proteins within the endoplasmic reticulum (ER), leading to phosphorylation of eIF2α and translational attenuation.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Department of Agrarian and Exact, Universidade Estadual da Paraíba, Catolé do Rocha 58884-000, PB, Brazil.
Freshwater depletion becomes a significant challenge as the population grows and food demand rises. We evaluated the responses of lettuce cultivars () under saline stress in photosynthetic responses, production, and ion homeostasis. We used a randomized block design in a 3 × 5 factorial scheme with five replications-the first factor: three cultivars of curly lettuce: SVR 2005, Simpson, and Grand Rapids.
View Article and Find Full Text PDFMolecules
January 2025
Institute of Bioorganic & Medicinal Chemistry, Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
The overprescription of antibiotics in medicine and agriculture has accelerated the development and spread of antibiotic resistance in bacteria, which severely limits the arsenal available to clinicians for treating bacterial infections. This work discovered a new class of heteroarylcyanovinyl quinazolones and quinazolone pyridiniums to surmount the increasingly severe bacterial resistance. Bioactive assays manifested that the highly active compound exhibited strong inhibition against MRSA and with extremely low MICs of 0.
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