1. Excessive transcription-replication conflicts are a vulnerability of BRCA1-mutant cancers.
- Author
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Patel PS, Algouneh A, Krishnan R, Reynolds JJ, Nixon KCJ, Hao J, Lee J, Feng Y, Fozil C, Stanic M, Yerlici T, Su P, Soares F, Liedtke E, Prive G, Baider GD, Pujana MA, Mekhail K, He HH, Hakem A, Stewart GS, and Hakem R
- Subjects
- Humans, RNA Polymerase II metabolism, Promoter Regions, Genetic, Methyltransferases deficiency, Methyltransferases genetics, R-Loop Structures, Cell Death, BRCA1 Protein deficiency, BRCA1 Protein genetics, DNA Replication genetics, Hereditary Breast and Ovarian Cancer Syndrome genetics, Hereditary Breast and Ovarian Cancer Syndrome pathology, Hereditary Breast and Ovarian Cancer Syndrome physiopathology, Mutation, Transcription, Genetic genetics
- Abstract
BRCA1 mutations are associated with increased breast and ovarian cancer risk. BRCA1-mutant tumors are high-grade, recurrent, and often become resistant to standard therapies. Herein, we performed a targeted CRISPR-Cas9 screen and identified MEPCE, a methylphosphate capping enzyme, as a synthetic lethal interactor of BRCA1. Mechanistically, we demonstrate that depletion of MEPCE in a BRCA1-deficient setting led to dysregulated RNA polymerase II (RNAPII) promoter-proximal pausing, R-loop accumulation, and replication stress, contributing to transcription-replication collisions. These collisions compromise genomic integrity resulting in loss of viability of BRCA1-deficient cells. We also extend these findings to another RNAPII-regulating factor, PAF1. This study identifies a new class of synthetic lethal partners of BRCA1 that exploit the RNAPII pausing regulation and highlight the untapped potential of transcription-replication collision-inducing factors as unique potential therapeutic targets for treating cancers associated with BRCA1 mutations., (© The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2023
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