title: Wee1 is required to sustain ATR/Chk1 signaling upon replicative stress.
abstract: The therapeutic efficacy of nucleoside analogues, e.g. gemcitabine, against cancer cells can be augmented by inhibitors of checkpoint kinases, including Wee1, ATR, and Chk1. We have compared the chemosensitizing effect of these inhibitors in cells derived from pancreatic cancer, a tumor entity where gemcitabine is part of the first-line therapeutic regimens, and in osteosarcoma-derived cells. As expected, all three inhibitors rendered cancer cells more sensitive to gemcitabine, but Wee1 inhibition proved to be particularly efficient in this context. Investigating the reasons for this potent sensitizing effect, we found that Wee1 inhibition or knockdown not only blocked Wee1 activity, but also reduced the activation of ATR/Chk1 in gemcitabine-treated cells. Combination of several inhibitors revealed that Wee1 inhibition requires Cyclin-dependent kinases 1 and 2 (Cdk1/2) and Polo-like kinase 1 (Plk1) to reduce ATR/Chk1 activity. Through activation of Cdks and Plk1, Wee1 inhibition reduces Claspin and CtIP levels, explaining the impairment in ATR/Chk1 activity. Taken together, these results confer a consistent signaling pathway reaching from Wee1 inhibition to impaired Chk1 activity, mechanistically dissecting how Wee1 inhibitors not only dysregulate cell cycle progression, but also enhance replicative stress and chemosensitivity towards nucleoside analogues.
authors.affiliation: Institute of Molecular Oncology, Göttingen Centre of Molecular Biosciences (GZMB), Faculty of Medicine, University of Göttingen, Göttingen, Germany.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Saini
authors.affiliation: Institute of Molecular Oncology, Göttingen Centre of Molecular Biosciences (GZMB), Faculty of Medicine, University of Göttingen, Göttingen, Germany.
authors.forename: Yizhu
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Molecular Oncology, Göttingen Centre of Molecular Biosciences (GZMB), Faculty of Medicine, University of Göttingen, Göttingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Dobbelstein
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D004357:Drug Synergism; D006801:Humans; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D011494:Protein Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D015398:Signal Transduction; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D003841:Deoxycytidine; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D000093542:Gemcitabine
keywords: ATR signaling pathway; Wee1; checkpoint kinases; gemcitabine; replicative stress