title: Mdm2 inhibition confers protection of p53-proficient cells from the cytotoxic effects of Wee1 inhibitors.
abstract: Pharmacological inhibition of the cell cycle regulatory kinase Wee1 represents a promising strategy to eliminate cancer cells. Wee1 inhibitors cooperate with chemotherapeutics, e. g. nucleoside analogues, pushing malignant cells from S phase towards premature mitosis and death. However, considerable toxicities are observed in preclinical and clinical trials. A high proportion of tumor cells can be distinguished from all other cells of a patient's body by inactivating mutations in the tumor suppressor p53. Here we set out to develop an approach for the selective protection of p53-proficient cells against the cytotoxic effects of Wee1 inhibitors. We pretreated such cells with Nutlin-3a, a prototype inhibitor of the p53-antagonist Mdm2. The resulting transient cell cycle arrest effectively increased the survival of cells that were subsequently treated with combinations of the Wee1 inhibitor MK-1775 and/or the nucleoside analogue gemcitabine. In this constellation, Nutlin-3a reduced caspase activation and diminished the phosphorylation of Histone 2AX, an indicator of the DNA damage response. Both effects were strictly dependent on the presence of p53. Moreover, Nutlin pre-treatment reduced the fraction of cells that were undergoing premature mitosis in response to Wee1 inhibition. We conclude that the pre-activation of p53 through Mdm2 antagonists serves as a viable option to selectively protect p53-proficient cells against the cytotoxic effects of Wee1 inhibitors, especially when combined with a nucleoside analogue. Thus, Mdm2 antagonists might prove useful to avoid unwanted side effects of Wee1 inhibitors. On the other hand, when a tumor contains wild type p53, care should be taken not to induce its activity before applying Wee1 inhibitors.
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: 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: Anusha
authors.initials: A
authors.lastname: Sriraman
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: D020169:Caspases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D045325:HCT116 Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D018613:Microscopy, Confocal; D008938:Mitosis / Q000187:drug effects; D009154:Mutation; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011744:Pyrimidinones; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D000093542:Gemcitabine
chemical_list: D018797:Cell Cycle Proteins; C468783:H2AX protein, human; D006657:Histones; D007093:Imidazoles; D009687:Nuclear Proteins; D010879:Piperazines; D011720:Pyrazoles; D011743:Pyrimidines; D011744:Pyrimidinones; D016159:Tumor Suppressor Protein p53; D003841:Deoxycytidine; C482205:nutlin 3; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D020169:Caspases; C549567:adavosertib; D000093542:Gemcitabine
keywords: Mdm2; Wee1; gemcitabine; p53; premature mitosis