Abstract
Prior studies have demonstrated that inhibition of CHK1 can promote the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and phosphorylation of histone H2AX and that inhibition of poly(ADP-ribose) polymerase 1 (PARP1) can affect growth factor-induced ERK1/2 activation. The present studies were initiated to determine whether CHK1 inhibitors interacted with PARP1 inhibition to facilitate apoptosis. Transient expression of dominant-negative CHK1 raised basal ERK1/2 activity and prevented CHK1 inhibitors from activating ERK1/2. CHK1 inhibitors modestly increased the levels of PARP1 ADP ribosylation and molecular or small-molecule inhibition of PARP1 blocked CHK1 inhibitor-stimulated histone H2AX phosphorylation and activation of ERK1/2. Stimulated histone H2AX phosphorylation was ataxia telangiectasia-mutated protein-dependent. Multiple CHK1 inhibitors interacted in a greater than additive fashion with multiple PARP1 inhibitors to cause transformed cell-killing in short-term viability assays and synergistically killed tumor cells in colony-formation assays. Overexpression of BCL-xL or loss of BAX/BAK function, but not the function of BID, suppressed CHK1 inhibitor + PARP1 inhibitor lethality. Inhibition of BCL-2 family protein function enhanced CHK1 inhibitor + PARP1 inhibitor lethality and restored drug-induced cell-killing in cells overexpressing BCL-xL. Thus, PARP1 plays an important role in regulating the ability of CHK1 inhibitors to activate ERK1/2 and the DNA damage response. An inability of PARP1 to modulate this response results in transformed cell death mediated through the intrinsic apoptosis pathway.
Footnotes
This work was funded by the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant R01-DK52825]; the National Institutes of Health National Cancer Institute [Grants P01-CA104177; R01-CA108325; R01-CA150214]; Department of Defense Awards [Grants DAMD17-03-1-0262; W81XWH-10-1-0009]; The Jim Valvano “Jimmy V” Foundation; The Goodwin Foundation; and the Universal Inc. Professorship in Signal Transduction Research (P.D.).
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
doi:10.1124/mol.110.067199.
-
ABBREVIATIONS:
- UCN-01
- 7-hydroxystaurosporine
- ERK
- extracellular signal-regulated kinase
- MEK
- mitogen-activated protein kinase kinase
- m.o.i.
- multiplicity of infection
- DMSO
- dimethyl sulfoxide
- ATM
- ataxia telangiectasia-mutated
- PAGE
- polyacrylamide gel electrophoresis
- CI
- combination index
- FBS
- fetal bovine serum
- GAPDH
- glyceraldehyde-3-phosphate dehydrogenase
- siRNA
- small interfering RNA
- PARP1
- poly(ADP-ribose) polymerase 1
- AZD7762
- 5-(3-fluoro-phenyl)-3-ureido-thiophene-2-carboxylic acid (S)-piperidin-3-ylamide hydrochloride
- GPI15427
- 10-(4-methyl-piperazin-1-ylmethyl)-2H-7-oxa-1,2-diaza-benzo[de]anthracen-3-one
- NU1025
- 8-hydroxy-2-methyl-4(3H)-quinazolinone
- AZD2281
- olaparib
- EE
- [Glu218,Glu222]Mek1
- PD184352
- 2-(2-chloro-4-iodo-phenylamino)-N-cyclopropylmethoxy-3,4-difluoro-benzamide
- PD98059
- 2′-amino-3′-methoxyflavone
- PJ34
- N-(5,6-dihydro-6-oxo-2-phenanthridinyl)-2-acetamide hydrochloride
- AG1478
- 4-(3′-chloroanilino)-6,7-dimethoxy-quinazoline
- GX15-070
- obatoclax
- ABT888
- veliparib
- HA14-1
- 2-amino-6-bromo-a-cyano-3-(ethoxycarbonyl)-4H-1-benzopy ran-4-acetic acid ethyl ester
- ABT-263
- navitoclax
- KU55933
- 2-(4-morpholinyl)-6-(1-thianthrenyl)-4H-pyran-4-one
- CEP6800
- 10-(aminomethyl)-4,5,6,7-tetrahydro-1H-cyclopenta[a]pyrrolo[3,4-c]carbazole-1,3(2H)-dione.
- Received June 29, 2010.
- Accepted August 9, 2010.
- Copyright © 2010 The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|
