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Sokhi S, Lewis CW, Bukhari AB, Hadfield J, Xiao EJ, Fung J, Yoon YJ, Hsu WH, Gamper AM, Chan GK. Myt1 overexpression mediates resistance to cell cycle and DNA damage checkpoint kinase inhibitors. Front Cell Dev Biol 2023; 11:1270542. [PMID: 38020882 PMCID: PMC10652759 DOI: 10.3389/fcell.2023.1270542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Cell cycle checkpoint kinases serve as important therapeutic targets for various cancers. When they are inhibited by small molecules, checkpoint abrogation can induce cell death or further sensitize cancer cells to other genotoxic therapies. Particularly aberrant Cdk1 activation at the G2/M checkpoint by kinase inhibitors causing unscheduled mitotic entry and mitotic arrest was found to lead to DNA damage and cell death selectively in cancer cells. Promising drugs inhibiting kinases like Wee1 (Adavosertib), Wee1+Myt1 (PD166285), ATR (AZD6738) and Chk1 (UCN-01) have been developed, but clinical data has shown variable efficacy for them with poorly understood mechanisms of resistance. Our lab recently identified Myt1 as a predictive biomarker of acquired resistance to the Wee1 kinase inhibitor, Adavosertib. Here, we investigate the role of Myt1 overexpression in promoting resistance to inhibitors (PD166285, UCN-01 and AZD6738) of other kinases regulating cell cycle progression. We demonstrate that Myt1 confers resistance by compensating Cdk1 inhibition in the presence of these different kinase inhibitors. Myt1 overexpression leads to reduced premature mitotic entry and decreased length of mitosis eventually leading to increased survival rates in Adavosertib treated cells. Elevated Myt1 levels also conferred resistance to inhibitors of ATR or Chk1 inhibitor. Our data supports that Myt1 overexpression is a common mechanism by which cancer cells can acquire resistance to a variety of drugs entering the clinic that aim to induce mitotic catastrophe by abrogating the G2/M checkpoint.
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Affiliation(s)
- Sargun Sokhi
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Cody W. Lewis
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Amirali B. Bukhari
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Joanne Hadfield
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Edric J. Xiao
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Jeremy Fung
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
| | - Yea Jin Yoon
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
| | - Wen-Hsin Hsu
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Armin M. Gamper
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Gordon K. Chan
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
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Hadfield JD, Sokhi S, Chan GK. Cell Synchronization Techniques for Studying Mitosis. Methods Mol Biol 2022; 2579:73-86. [PMID: 36045199 DOI: 10.1007/978-1-0716-2736-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cell synchronization allows the examination of cell cycle progression. Nocodazole and other microtubule poisons have been used extensively to interfere with microtubule function and arrest cells in mitosis. Since microtubules are important for many cellular functions, alternative cell cycle synchronization techniques independent of microtubule inhibition are also used for synchronizing cells in mitosis. Here we describe using nocodazole, STLC, and combining thymidine block with MG132 to synchronize cells in mitosis. These inhibitors are reversible and mitotic cells can be released into the G1 phase synchronously. These techniques can be applied to both Western blot and timelapse imaging to study mitotic progression.
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Affiliation(s)
- Joanne D Hadfield
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Sargun Sokhi
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada
| | - Gordon K Chan
- Department of Oncology, University of Alberta, Edmonton, AB, Canada.
- Experimental Oncology, Cross Cancer Institute, Edmonton, AB, Canada.
- Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, AB, Canada.
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