Combined inhibition of Chk1 and Wee1: in vitro synergistic effect translates to tumor growth inhibition in vivo.
Targeting Chk1 protein kinase can enhance the antitumor effects of radio- and chemotherapy. Recent evidence disclosed a role of Chk1 in unperturbed cell proliferation and survival, implying that Chk1 inhibitors could also be effective as single agents in tumors with a specific genetic background. To identify genes in synthetic lethality with Chk1, we did a high-throughput screening using a siRNA library directed against 719 human protein kinases in the human ovarian cancer cell line OVCAR-5, resistant to Chk1 inhibitors. Wee1 tyrosine kinase was the most significant gene in synthetic lethality with Chk1. Treatment with non-toxic concentrations of a Chk1 inhibitor (PF-00477736) and a Wee1 inhibitor (MK-1775) confirmed the marked synergistic effect in various human cancer cell lines (breast, ovarian, colon, prostate), independently of the p53 status. Detailed molecular analysis showed that the combination caused cancer cells to undergo premature mitosis before the end of DNA replication, with damaged DNA leading to cell death partly by apoptosis. In vivo treatment of mice bearing OVCAR-5 xenografts with the combination of Chk1 and Wee1 inhibitors led to greater tumor growth inhibition than with the inhibitors used as single agents with no toxicity. These data provide a strong rationale for the clinical investigation of the combination of a Chk1 and a Wee1 inhibitor.
Laboratory of Molecular Pharmacology, Department of Oncology, Istituto di Ricerche Farmacologiche "Mario Negri", Milan, Italy. laura.carrassa@marionegri.it
Laura
L
Carrassa
Rosaria
R
Chilà
Monica
M
Lupi
Francesca
F
Ricci
Cinzia
C
Celenza
Marco
M
Mazzoletti
Massimo
M
Broggini
Giovanna
G
Damia
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001570:Benzodiazepinones / Q000494:pharmacology / Q000627:therapeutic use; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D004261:DNA Replication / Q000187:drug effects; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008938:Mitosis / Q000187:drug effects; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010051:Ovarian Neoplasms / Q000188:drug therapy; D047428:Protein Kinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology / Q000627:therapeutic use; D011743:Pyrimidines / Q000494:pharmacology / Q000627:therapeutic use; D011744:Pyrimidinones; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014183:Transplantation, Heterologous
D001570:Benzodiazepinones; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C532366:PF 00477736; D047428:Protein Kinase Inhibitors; D011720:Pyrazoles; D011743:Pyrimidines; D011744:Pyrimidinones; D034741:RNA, Small Interfering; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse; C549567:adavosertib