1. BRCA1 levels and DNA-damage response are controlled by the competitive binding of circHIPK3 or FMRP to the BRCA1 mRNA.
- Author
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Grelloni C, Garraffo R, Setti A, Rossi F, Peruzzi G, Cinquanta M, Di Rosa MC, Pierotti MA, Beltran M, and Bozzoni I
- Subjects
- Humans, Binding, Competitive, Intracellular Signaling Peptides and Proteins metabolism, Intracellular Signaling Peptides and Proteins genetics, Gene Expression Regulation, Neoplastic, Breast Neoplasms genetics, Breast Neoplasms metabolism, Breast Neoplasms pathology, RNA metabolism, RNA genetics, HEK293 Cells, Protein Binding, Cell Line, Tumor, Protein Biosynthesis, MCF-7 Cells, Female, BRCA1 Protein metabolism, BRCA1 Protein genetics, RNA, Circular metabolism, RNA, Circular genetics, RNA, Messenger metabolism, RNA, Messenger genetics, DNA Damage, Fragile X Mental Retardation Protein metabolism, Fragile X Mental Retardation Protein genetics, Protein Serine-Threonine Kinases metabolism, Protein Serine-Threonine Kinases genetics
- Abstract
Circular RNAs (circRNAs) are covalently closed RNA molecules widely expressed in eukaryotes and deregulated in several pathologies, including cancer. Many studies point to their activity as microRNAs (miRNAs) and protein sponges; however, we propose a function based on circRNA-mRNA interaction to regulate mRNA fate. We show that the widely tumor-associated circHIPK3 directly interacts in vivo with the BRCA1 mRNA through the back-splicing region in human cancer cells. This interaction increases BRCA1 translation by competing for the binding of the fragile-X mental retardation 1 protein (FMRP) protein, which we identified as a BRCA1 translational repressor. CircHIPK3 depletion or disruption of the circRNA-mRNA interaction decreases BRCA1 protein levels and increases DNA damage, sensitizing several cancer cells to DNA-damage-inducing agents and rendering them susceptible to synthetic lethality. Additionally, blocking FMRP interaction with BRCA1 mRNA with locked nucleic acid (LNA) restores physiological protein levels in BRCA1 hemizygous breast cancer cells, underscoring the importance of this circRNA-mRNA interaction in regulating DNA-damage response., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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