CHK1 overexpression in T-cell acute lymphoblastic leukemia is essential for proliferation and survival by preventing excessive replication stress

L. M. Sarmento, V. Póvoa, R. Nascimento, G. Real, I. Antunes, L. R. Martins, C. Moita, P. M. Alves, M. Abecasis, L. F. Moita, R. M E Parkhouse, J. P P Meijerink, J. T. Barata

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36 Citations (Scopus)

Abstract

Checkpoint kinase 1 (CHK1) is a key component of the ATR (ataxia telangiectasia-mutated and Rad3-related)-dependent DNA damage response pathway that protect cells from replication stress, a cell intrinsic phenomenon enhanced by oncogenic transformation. Here, we show that CHK1 is overexpressed and hyperactivated in T-cell acute lymphoblastic leukemia (T-ALL). CHEK1 mRNA is highly abundant in patients of the proliferative T-ALL subgroup and leukemia cells exhibit constitutively elevated levels of the replication stress marker phospho-RPA32 and the DNA damage marker γH2AX. Importantly, pharmacologic inhibition of CHK1 using PF-004777736 or CHK1 short hairpin RNA-mediated silencing impairs T-ALL cell proliferation and viability. CHK1 inactivation results in the accumulation of cells with incompletely replicated DNA, ensuing DNA damage, ATM/CHK2 activation and subsequent ATM- and caspase-3-dependent apoptosis. In contrast to normal thymocytes, primary T-ALL cells are sensitive to therapeutic doses of PF-004777736, even in the presence of stromal or interleukin-7 survival signals. Moreover, CHK1 inhibition significantly delays in vivo growth of xenotransplanted T-ALL tumors. We conclude that CHK1 is critical for T-ALL proliferation and viability by downmodulating replication stress and preventing ATM/caspase-3-dependent cell death. Pharmacologic inhibition of CHK1 may be a promising therapeutic alternative for T-ALL treatment.

Original languageEnglish
Pages (from-to)2978-2990
Number of pages13
JournalOncogene
Volume34
Issue number23
DOIs
Publication statusPublished - 4 Jun 2015

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    Sarmento, L. M., Póvoa, V., Nascimento, R., Real, G., Antunes, I., Martins, L. R., ... Barata, J. T. (2015). CHK1 overexpression in T-cell acute lymphoblastic leukemia is essential for proliferation and survival by preventing excessive replication stress. Oncogene, 34(23), 2978-2990. https://doi.org/10.1038/onc.2014.248