CDK5RAP3, a New BRCA2 Partner That Regulates DNA Repair, Is Associated with Breast Cancer Survival.

Jordi Minguillón,Helena Montanuy,Massimo Bogliolo,Pilar Bustamante-Madrid,Cristina Camps-Fajol,Conxi Lázaro,Hermela Shimelis,Fergus J Couch,Griselda Martrat,Jordi Surrallés,Pau Castillo,Daniel Cuadras,Llorenç Rovirosa,Roser Pujol,Penny Soucy,Javier Machín Gayarre ,Miquel Àngel Pujana ,María José García ,Gorka Ruíz De Garibay ,Antonio Gómez,Gonzalo Hernández ,Marı́a José Ramı́rez ,Javier Benı́tez ,Null Author_Id

doi:10.3390/cancers14020353

Abstract

Simple SummaryBRCA2 is an essential gene for DNA repair by homologous recombination and is often mutated in families at risk of breast and ovarian cancer. In this study we identified CDK5RAP3 tumor suppressor as a new BRCA2-interacting protein. CDK5RAP3 negatively regulates DNA repair of double-strand breaks, providing a new mechanism of DNA damage resistance. Consistently, gene expression data analysis showed CDK5RAP3 overexpression in breast cancer is associated with poorer survival. Finally, we identified common genetic variations in the CDK5RAP3 locus as potentially associated with breast and ovarian cancer risk in a large cohort of BRCA1 and BRCA2 mutation carriers.BRCA2 is essential for homologous recombination DNA repair. BRCA2 mutations lead to genome instability and increased risk of breast and ovarian cancer. Similarly, mutations in BRCA2-interacting proteins are also known to modulate sensitivity to DNA damage agents and are established cancer risk factors. Here we identify the tumor suppressor CDK5RAP3 as a novel BRCA2 helical domain-interacting protein. CDK5RAP3 depletion induced DNA damage resistance, homologous recombination and single-strand annealing upregulation, and reduced spontaneous and DNA damage-induced genomic instability, suggesting that CDK5RAP3 negatively regulates double-strand break repair in the S-phase. Consistent with this cellular phenotype, analysis of transcriptomic data revealed an association between low CDK5RAP3 tumor expression and poor survival of breast cancer patients. Finally, we identified common genetic variations in the CDK5RAP3 locus as potentially associated with breast and ovarian cancer risk in BRCA1 and BRCA2 mutation carriers. Our results uncover CDK5RAP3 as a critical player in DNA repair and breast cancer outcomes.

Highlights

BRCA2, the breast cancer type 2 susceptibility gene product, is a master regulator of the DNA damage response pathway
A screening for physical interactors of BRCA2 identified CDK5RAP3, which emerged as a critical regulator of DNA double-strand breaks (DSBs) repair that is associated with breast cancer outcomes
We screened for BRCA2 interactors by applying the yeast two-hybrid system and five baits based on Pfam-predicted domains and PONDR-predicted disordered regions [22], which overall covered most of the functionally important BRCA2 domains/regions (Figure 1A)

Summary

Introduction

BRCA2, the breast cancer type 2 susceptibility gene product, is a master regulator of the DNA damage response pathway. BRCA2 is involved in DNA repair by homologous recombination (HR) and maintains genomic stability to counteract the mutational load due to double-strand breaks (DSBs) and interstrand crosslink (ICL) inducers [1,2]. Monoallelic and biallelic mutations in BRCA2 cause hereditary breast and ovarian cancer and Fanconi anaemia (FA), respectively [6,7,8,9]. Similar causative associations have been described for other genes of the FA/BRCA pathway, including BRCA1, PALB2, and RAD51C [10,11,12,13,14,15]. A screening for physical interactors of BRCA2 identified CDK5RAP3, which emerged as a critical regulator of DNA DSB repair that is associated with breast cancer outcomes

Methods

Results

Conclusion