14-3-3sigma and p21 synergize to determine DNA damage response following Chk2 inhibition.
DNA damage checkpoints are critical for preventing tumorigenesis and regulating the response of cells to genotoxic agents. It is believed that the coordinated actions of a number of effectors underlie proper checkpoint function. The kinase Chk2, p21 and 14-3-3sigma have each been shown to be independent effectors of the G(2) DNA damage checkpoint. However, the relative roles of these proteins remain unclear. To help elucidate this question, we have perturbed each of these 3 genes in combination in human cells. We show that Chk2 depletion causes markedly increased sensitivity to DNA damage in p21(-/-), 14-3-3sigma(-/-) cells but not in cells lacking only one or none of these genes. This greater sensitivity was due to an increase in apoptosis following DNA damage and not due to exacerbation of G(2) checkpoint defects. Pharmacologic inhibition of Chk2 in p21(-/-), 14-3-3sigma(-/-) cells also resulted in greater sensitivity to DNA damage. Our data indicates that p21 and 14-3-3sigma synergize as molecular determinants of sensitivity to DNA damage following Chk2 inhibition, and Chk2 modulates the biological rheostat that determines whether a cancer cell undergoes arrest versus death after treatment with a chemotherapeutic agent. These findings have implications for the targeting of Chk2 in human cancers.
Meng
Shasha
S
Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
Arbit
Tali
T
Veeriah
Selvaraju
S
Mellinghoff
Ingo K
IK
Fang
Fang
F
Vivanco
Igor
I
Rohle
Dan
D
Chan
Timothy A
TA
D048948:14-3-3 Proteins; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D064007:Ataxia Telangiectasia Mutated Proteins; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D064447:Checkpoint Kinase 2; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D005092:Exonucleases / Q000235:genetics / Q000378:metabolism*; D005095:Exoribonucleases; D016195:G2 Phase; D055785:Gene Knockdown Techniques; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D048948:14-3-3 Proteins; D000903:Antibiotics, Antineoplastic; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D004317:Doxorubicin; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases; D005092:Exonucleases; D005095:Exoribonucleases; C413442:SFN protein, human