TY - JOUR
T1 - Genome-Protective Topoisomerase 2a-Dependent G2 Arrest Requires p53 in hTERT-Positive Cancer Cells
AU - Lockwood, Nicola
AU - Martini, Silvia
AU - López-Pardo, Ainara
AU - Deiss, Katharina
AU - Segeren, Hendrika A
AU - Semple, Robert K
AU - Collins, Ian
AU - Repana, Dimitra
AU - Cobbaut, Mathias
AU - Soliman, Tanya N
AU - Ciccarelli, Francesca
AU - Parker, Peter J
N1 - Funding Information:
This work was supported by The Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001130), the UK Medical Research Council (FC001130), and the Wellcome Trust (FC001130). R.K. Semple is funded by the Wellcome Trust (grant 210752/Z/18/Z). D. Repana was supported by a Fellowship from the Health Education England Genomics Education Programme. For the purpose of Open Access, the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission. The authors would like to thank The Francis Crick Institute STPs for support with this research, in particular the High-Throughput Screening Laboratory, Light Microscopy, Flow Cytometry, Experimental Histopathology, Biological Research Facility and Cell Services. They also thank Karen Vousden and Simon Boulton for their insightful discussion and gifting reagents and acknowledge Mariia Yuneva and Kanaga Sabapathy for kindly gifting cell lines.
Funding Information:
I. Collins reports other support from The Institute of Cancer Research, grants and personal fees from Cancer Research UK, grants from Cancer Research UK Pioneeer Fund, grants and other support from Sareum Ltd., and personal fees and other support from Sierra Oncology during the conduct of the study; grants and other support from The Institute of Cancer Research and Monte Rosa Therapeutics Inc., grants and personal fees from Cancer Research UK, grants from Merck KGaA and Medical Research Council, personal fees from Epidarex LLP, Dunad Therapeutics, Cardiff University, and nonfinancial support from Atomwise outside the submitted work; in addition, I. Collins has a patent for WO2009004329 issued and licensed to Sierra Oncology, a patent for WO2009044162 issued and licensed to Sierra Oncology, a patent for WO2009103966 pending and licensed to Sierra Oncology, a patent for WO2008075007 issued and licensed to Sierra Oncology, a patent for WO2013068755 pending and licensed to Sierra Oncology, a patent for WO2013171470 issued and
Funding Information:
This work was supported by The Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001130), the UK Medical Research Council (FC001130), and the Wellcome Trust (FC001130). R.K. Semple is funded by the Wellcome Trust (grant 210752/Z/18/Z). D. Repana was supported by a Fellowship from the Health Education England Genomics Education Programme. For the purpose of Open Access, the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission. The authors would like to thank The Francis Crick Institute STPs for support with this research, in particular the High-Throughput Screening Laboratory, Light Microscopy, Flow Cytometry, Experimental Histopathology, Biological Research Facility and Cell Services. They also thank Karen Vousden and Simon Boulton for their insightful discussion and gifting reagents and acknowledge Mariia Yuneva and Kanaga Saba-pathy for kindly gifting cell lines.
Publisher Copyright:
©2022 American Association for Cancer Research
PY - 2022/5/3
Y1 - 2022/5/3
N2 - Topoisomerase 2a (Topo2a)-dependent G
2 arrest engenders faithful segregation of sister chromatids, yet in certain tumor cell lines where this arrest is dysfunctional, a PKCe-dependent failsafe pathway can be triggered. Here we elaborate on recent advances in understanding the underlying mechanisms associated with this G
2 arrest by determining that p53–p21 signaling is essential for efficient arrest in cell lines, in patient-derived cells, and in colorectal cancer organoids. Regulation of this p53 axis required the SMC5/6 complex, which is distinct from the p53 pathways observed in the DNA damage response. Topo2a inhibition specifically during S phase did not trigger G
2 arrest despite affecting completion of DNA replication. Moreover, in cancer cells reliant upon the alternative lengthening of telomeres (ALT) mechanism, a distinct form of Topo2a-dependent, p53-independent G
2 arrest was found to be mediated by BLM and Chk1. Importantly, the previously described PKCe-dependent mitotic failsafe was engaged in hTERT-positive cells when Topo2a-dependent G
2 arrest was dysfunctional and where p53 was absent, but not in cells dependent on the ALT mechanism. In PKCe knockout mice, p53 deletion elicited tumors were less aggressive than in PKCe-replete animals and exhibited a distinct pattern of chromosomal rearrangements. This evidence suggests the potential of exploiting synthetic lethality in arrest-defective hTERT-positive tumors through PKCe-directed therapeutic intervention. Significance: The identification of a requirement for p53 in stringent Topo2a-dependent G
2 arrest and engagement of PKCe failsafe pathways in arrest-defective hTERT-positive cells provides a therapeutic opportunity to induce selective synthetic lethality.
AB - Topoisomerase 2a (Topo2a)-dependent G
2 arrest engenders faithful segregation of sister chromatids, yet in certain tumor cell lines where this arrest is dysfunctional, a PKCe-dependent failsafe pathway can be triggered. Here we elaborate on recent advances in understanding the underlying mechanisms associated with this G
2 arrest by determining that p53–p21 signaling is essential for efficient arrest in cell lines, in patient-derived cells, and in colorectal cancer organoids. Regulation of this p53 axis required the SMC5/6 complex, which is distinct from the p53 pathways observed in the DNA damage response. Topo2a inhibition specifically during S phase did not trigger G
2 arrest despite affecting completion of DNA replication. Moreover, in cancer cells reliant upon the alternative lengthening of telomeres (ALT) mechanism, a distinct form of Topo2a-dependent, p53-independent G
2 arrest was found to be mediated by BLM and Chk1. Importantly, the previously described PKCe-dependent mitotic failsafe was engaged in hTERT-positive cells when Topo2a-dependent G
2 arrest was dysfunctional and where p53 was absent, but not in cells dependent on the ALT mechanism. In PKCe knockout mice, p53 deletion elicited tumors were less aggressive than in PKCe-replete animals and exhibited a distinct pattern of chromosomal rearrangements. This evidence suggests the potential of exploiting synthetic lethality in arrest-defective hTERT-positive tumors through PKCe-directed therapeutic intervention. Significance: The identification of a requirement for p53 in stringent Topo2a-dependent G
2 arrest and engagement of PKCe failsafe pathways in arrest-defective hTERT-positive cells provides a therapeutic opportunity to induce selective synthetic lethality.
UR - http://www.scopus.com/inward/record.url?scp=85129780934&partnerID=8YFLogxK
U2 - 10.1158/0008-5472.CAN-21-1785
DO - 10.1158/0008-5472.CAN-21-1785
M3 - Article
C2 - 35247890
SN - 0008-5472
VL - 82
SP - 1762
EP - 1773
JO - Cancer Research
JF - Cancer Research
IS - 9
ER -