CRISPR Used in Triple Negative Breast Cancer Research



June 9, 2021

The cover paper for Oncotarget Volume 12, Issue 12 is entitled, "Frame-shift mediated reduction of gain-of-function p53 R273H and deletion of the R273H C-terminus in breast cancer cells result in replication-stress sensitivity," by researchers from the Department of Biological Sciences Hunter College, Belfer Building, City University of New York, NY; The Graduate Center Biology and Biochemistry Programs of City University of New York, NY; Department of Biological Sciences, Columbia University, NY; Department of Cell and Developmental Biology, Weill Cornell Medical College, NY. Abstract: We recently documented that gain-of-function (GOF) mutant p53 (mtp53) R273H in triple negative breast cancer (TNBC) cells interacts with replicating DNA and PARP1. The missense R273H GOF mtp53 has a mutated central DNA binding domain that renders it unable to bind specifically to DNA, but maintains the capacity to interact tightly with chromatin. Both the C-terminal domain (CTD) and oligomerization domain (OD) of GOF mtp53 proteins are intact and it is unclear whether these regions of mtp53 are responsible for chromatin-based DNA replication activities. We generated MDA-MB-468 cells with CRISPR-Cas9 edited versions of the CTD and OD regions of mtp53 R273H. These included a frame-shift mtp53 R273Hfs387, which depleted mtp53 protein expression; mtp53 R273HΔ381-388, which had a small deletion within the CTD; and mtp53 R273HΔ347-393, which had both the OD and CTD regions truncated. The mtp53 R273HΔ347-393 existed exclusively as monomers and disrupted the chromatin interaction of mtp53 R273H. The CRISPR variants proliferated more slowly than the parental cells and mt53 R273Hfs387 showed the most extreme phenotype. We uncovered that after thymidine-induced G1/S synchronization, but not hydroxyurea or aphidicholin, R273Hfs387 cells displayed impairment of S-phase progression while both R273HΔ347-393 and R273HΔ381-388 displayed only moderate impairment. Moreover, reduced chromatin interaction of MCM2 and PCNA in mtp53 depleted R273Hfs387 cells post thymidine-synchronization revealed delayed kinetics of replisome assembly underscoring the slow S-phase progression. Taken together our findings show that the CTD and OD domains of mtp53 R273H play critical roles in mutant p53 GOF that pertain to processes associated with DNA replication. Sign up for free Altmetric alerts about this article - DOI - Full text - Correspondence to - Jill Bargonetti - Keywords - mutant p53, gain-of-function, oligomerization, DNA replication, frame-shift, breast cancer About Oncotarget Oncotarget is a bi-weekly, peer-reviewed, open access biomedical journal covering research on all aspects of oncology. To learn more about Oncotarget, please visit or connect with: SoundCloud - Facebook - Twitter - YouTube - LinkedIn - Pinterest - Reddit - Oncotarget is published by Impact Journals, LLC please visit or connect with @ImpactJrnls Media Contact MEDIA@IMPACTJOURNALS.COM 18009220957

Cancer Research

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