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Lang F, Cornwell JA, Kaur K, Elmogazy O, Zhang W, Zhang M, Song H, Sun Z, Wu X, Aladjem MI, Aregger M, Cappell SD, Yang C. Abrogation of the G2/M checkpoint as a chemo sensitization approach for alkylating agents. Neuro Oncol 2023:noad252. [PMID: 38134889 DOI: 10.1093/neuonc/noad252] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND The cell cycle is tightly regulated by checkpoints, playing a vital role in controlling its progression and timing. Cancer cells exploit the G2/M checkpoint, which serves as a resistance mechanism against genotoxic anti-cancer treatments, allowing for DNA repair prior to cell division. Manipulating cell cycle timing has emerged as a potential strategy to augment the effectiveness of DNA damage-based therapies. METHODS In this study, we conducted a forward genome wide CRISPR/Cas9 screening with repeated exposure to the alkylating agent temozolomide (TMZ) to investigate the mechanisms underlying tumor cell survival under genotoxic stress. RESULTS Our findings revealed that canonical DNA repair pathways, including ATM/Fanconi and mismatch repair, determine cell fate under genotoxic stress. Notably, we identified the critical role of PKMYT1, in ensuring cell survival. Depletion of PKMYT1 led to overwhelming TMZ-induced cytotoxicity in cancer cells. Isobologram analysis demonstrated potent drug synergy between alkylating agents and a Myt1 kinase inhibitor, RP-6306. Mechanistically, inhibiting Myt1 forced G2/M-arrested cells into an unscheduled transition to the mitotic phase without complete resolution of DNA damage. This forced entry into mitosis, along with persistent DNA damage, resulted in severe mitotic abnormalities. Ultimately, these aberrations led to mitotic exit with substantial apoptosis. Preclinical animal studies demonstrated that the combination regimen involving TMZ and RP-6306 prolonged the overall survival of glioma-bearing mice. CONCLUSION Collectively, our findings highlight the potential of targeting cell cycle timing through Myt1 inhibition as an effective strategy to enhance the efficacy of current standard cancer therapies, potentially leading to improved disease outcomes.
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Affiliation(s)
- Fengchao Lang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - James A Cornwell
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, MD
| | - Karambir Kaur
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Omar Elmogazy
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Wei Zhang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Meili Zhang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Hua Song
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Zhonghe Sun
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, MD
| | - Xiaolin Wu
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, MD
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, MD
| | - Michael Aregger
- Molecular Targets Program, Center for Cancer Research, National Cancer Institute, MD
| | - Steven D Cappell
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, MD
| | - Chunzhang Yang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, MD
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Benton D, Jaeger EC, Kilner A, Kimble A, Lowry J, Schleicher EM, Power KM, Uibel D, Eisele C, Bowerman B, Lyczak R. Interactions between the WEE-1.3 kinase and the PAM-1 aminopeptidase in oocyte maturation and the early C. elegans embryo. G3 (Bethesda) 2021; 11:6157833. [PMID: 33681968 PMCID: PMC8049411 DOI: 10.1093/g3journal/jkab063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/23/2021] [Indexed: 11/25/2022]
Abstract
Puromycin-sensitive aminopeptidases are found across phyla and are known to regulate the cell-cycle and play a protective role in neurodegenerative disease. PAM-1 is a puromycin-sensitive aminopeptidase important for meiotic exit and polarity establishment in the one-cell Caenorhabditis elegans embryo. Despite conservation of this aminopeptidase, little is known about its targets during development. In order to identify novel interactors, we conducted a suppressor screen and isolated four suppressing mutations in three genes that partially rescued the maternal-effect lethality of pam-1 mutants. Suppressed strains show improved embryonic viability and polarization of the anterior–posterior axis. We identified a missense mutation in wee-1.3 in one of these suppressed strains. WEE-1.3 is an inhibitory kinase that regulates maturation promoting factor. Although the missense mutation suppressed polarity phenotypes in pam-1, it does so without restoring centrosome–cortical contact or altering the cortical actomyosin cytoskeleton. To see if PAM-1 and WEE-1.3 interact in other processes, we examined oocyte maturation. Although depletion of wee-1.3 causes sterility due to precocious oocyte maturation, this effect was lessened in pam-1 worms, suggesting that PAM-1 and WEE-1.3 interact in this process. Levels of WEE-1.3 were comparable between wild-type and pam-1 strains, suggesting that WEE-1.3 is not a direct target of the aminopeptidase. Thus, we have established an interaction between PAM-1 and WEE-1.3 in multiple developmental processes and have identified suppressors that are likely to further our understanding of the role of puromycin-sensitive aminopeptidases during development.
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Affiliation(s)
- Dorothy Benton
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Eva C Jaeger
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Arielle Kilner
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA.,Biomedical Studies Department, Graduate School of Biomedical Sciences and Professional Studies, Drexel University College of Medicine, 2900 W. Queen Lane Philadelphia, PA 19129, US A
| | - Ashley Kimble
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Josh Lowry
- Institute of Molecular Biology, 1229 University of Oregon, 1318 Franklin Blvd., Eugene, OR 97403, USA
| | - Emily M Schleicher
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Kaiden M Power
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Danielle Uibel
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Caprice Eisele
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
| | - Bruce Bowerman
- Institute of Molecular Biology, 1229 University of Oregon, 1318 Franklin Blvd., Eugene, OR 97403, USA
| | - Rebecca Lyczak
- Biology Department, Ursinus College, 601 E Main Street, Collegeville, PA 19426, USA
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