ATR kinase inhibition sensitizes quiescent human cells to the lethal effects of cisplatin but increases mutagenesis

Publication date: Available online 17 September 2019Source: Mutation Research/Fundamental and Molecular Mechanisms of MutagenesisAuthor(s): Rebekah J. Hutcherson, Michael G. KempAbstractThe ATR protein kinase is known to protect cells from DNA damage induced during the replicative phase of the cell cycle. Small molecule ATR kinase inhibitors have therefore been developed to improve the effectiveness of DNA damage-based chemotherapy regimens aimed at killing rapidly proliferating tumor cells. However, whether ATR functions in a similar manner in non-replicating cells has not been examined and is important considering the fact that most cells in the body, including cancer stem cells in solid tumors, normally reside in either a quiescent or differentiated non-replicating state. Using cultured human cell lines maintained in a quiescent or slowly growing state in vitro, ATR was found to be activated following treatment with the common anti-cancer drug cisplatin in a manner dependent on the nucleotide excision repair (NER) system. Moreover, treatment with the ATR kinase inhibitors VE-821 and AZD6738 enhanced quiescent cell killing and apoptotic signaling induced by cisplatin. However, ATR kinase inhibition in quiescent cells treated with a low concentration of cisplatin also elevated the level of mutagenesis at the hypoxanthine phosphoribosyltransferase locus and resulted in increased levels of PCNA mono-ubiquitination. These results suggest that the excision gaps generated by NER ...
Source: Mutation Research Fundamental and Molecular Mechanisms of Mutagenesis - Category: Cytology Source Type: research

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Source: Clinical Cancer Research - Category: Cancer & Oncology Authors: Tags: Clin Cancer Res Source Type: research
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Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
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Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
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