Abstract
Targeting DNA repair with poly(ADP-ribose) polymerase (PA RP) inhibitors has shown a broad range of anti-tumor activity in patients with advanced malignancies with and without BRCA deficiency. It remains unclear what role p53 plays in response to PA RP inhibition in BRCA-proficient cancer cells treated with DNA damaging agents. Using gene expression microarray analysis, we find that DNA damage response (DDR) pathways elicited by veliparib (ABT-888), a PA RP inhibitor, plus topotecan comprise the G1/S checkpoint, ATM and p53 signaling pathways in p53-wild-type cancer cell lines and BRCA1, BRCA2 and ATR pathway in p53-mutant lines. In contrast, topotecan alone induces the G 1/S checkpoint pathway in p53 wild-type lines and not in p53-mutant cells. These responses are coupled with G2/G1 checkpoint effectors p21CDKN1A upregulation, and Chk1 and Chk2 activation. The drug combination enhances G2 cell cycle arrest, apoptosis and a marked increase in cell death relative to topotecan alone in p53-wild-type and p53-mutant or -null cells. We also show that the checkpoint kinase inhibitor UCN-01 abolishes the G2 arrest induced by the veliparib and topotecan combination and further increases cell death in both p53-wild-type and -mutant cells. Collectively, PA RP inhibition by veliparib enhances DDR and cell death in BRCA-proficient cancer cells in a p53-dependent and -independent fashion. Abrogating the cell cycle arrest induced by PA RP inhibition plus chemotherapeutics may be a strategy in the treatment of BRCA-proficient cancer.
Original language | English (US) |
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Pages (from-to) | 4074-4082 |
Number of pages | 9 |
Journal | Cell Cycle |
Volume | 10 |
Issue number | 23 |
DOIs | |
State | Published - Dec 1 2011 |
Externally published | Yes |
Keywords
- DNA damaging agent
- Microarray
- P53
- Parp inhibition
- Topotecan
- Veliparib (ABT-888)
ASJC Scopus subject areas
- Molecular Biology
- Developmental Biology
- Cell Biology