Differential roles of ATR and ATM in p53, Chk1, and histone H2AX phosphorylation in response to hyperoxia: ATR-dependent ATM activation

Abstract

Elevated level of oxygen (hyperoxia) is widely used in critical care units and in respiratory insufficiencies. In addition, hyperoxia has been implicated in many diseases such as bronchopulmonary dysplasia or acute respiratory distress syndrome. Although hyperoxia is known to cause DNA base modifications and strand breaks, the DNA damage response has not been adequately investigated. We have investigated the effect of hyperoxia on DNA damage signaling and show that hyperoxia is a unique stress that activates the ataxia telangiectasia mutant (ATM)-and Rad3-related protein kinase (ATR)-dependent p53 phosphorylations (Ser6, -15, -37, and -392), phosphorylation of histone H2AX (Ser139), and phosphorylation of checkpoint kinase 1 (Chk1). In addition, we show that phosphorylation of p53 (Ser6) and histone H2AX (Ser139) depend on both ATM and ATR. We demonstrate that ATR activation precedes ATM activation in hyperoxia. Finally, we show that ATR is required for ATM activation in hyperoxia. Taken together, we report that ATR is the major DNA damage signal transducer in hyperoxia that activates ATM.

DNA damage signaling in response to 5-fluorouracil in three colorectal cancer cell lines with different mismatch repair and TP53 status

“…TP53 activation at Ser20/33/37 was seen in drug-treated TP53-proficient HCT116 cultures, suggesting BER and NER activity. These cultures (but not the TP53-depleted cultures which arrested at the G 1 /S border) arrested in S phase at 24 h and had high levels of apoptosis and phospho-H2AX, consistent with our previous study and other studies (29,41,42,(46)(47)(48). ATM was activated in response to continuous high-dose 5-FU in HCT15 cultures indicating DSB formation, but CHEK2 activation at Thr68 was not observed, consistent with the fact that this cell line carries the R145W mutation (on one allele of) the CHEK2 gene (26), resulting in a destabilized CHEK2 protein that cannot be phosphorylated by ATM at Thr68 (49).…”

“…An interesting question is how TP53 is activated in the absence of activated CHEK1 or CHEK2. Potential activators include BER-associated APEX1 (also known as REF-1) (38,39), p38 kinase (40), ATR or DNA-PK (18,41,42), but this remains unclear since we have not investigated expression of these proteins. Clinically-relevant bolus 5-FU treatment led to SSB and DSB formation in the MMR-proficient/TP53-deficient HT29 cultures as indicated by activation of ATM, CHEK1 and subsequently CHEK2.…”

Induction of mitosis delay, apoptosis and aneuploidy in human cells by phenyl hydroquinone, an Ames test-negative carcinogen

“…5). It was shown previously that histone H2AX undergoes phosphorylation in response to DNA damage such as oxidative damage (Tanaka et al, 2006;Kulkarni and Das, 2008). Moreover, PHQ did not efficiently induce base substitution-type mutations in bacterial systems (Brusick, 2005).…”

Glucose oscillations, more than constant high glucose, induce p53 activation and a metabolic memory in human endothelial cells

“…Additional studies examined whether this upregulation in p53 would persist after 1 week of glucose normalisation. We therefore measured p53 phosphorylation on serine 15, phosphorylation being generated by ATM as a consequence of DNA damage [13] (Fig. 2a).…”

“…ATM activation following genotoxic stress leads not only to formation of phospho-γ-H2AX, but also to p53 phosphorylation [12,13]. The role of the well known tumour suppressor transcription factor p53 in diabetes has long been undervalued.…”