Title

Comprehensive Mutational Analysis of the BRCA1-Associated DNA Helicase and Tumor-Suppressor FANCJ/BACH1/BRIP1

UMMS Affiliation

Department of Molecular, Cell and Cancer Biology; Department of Biochemistry and Molecular Pharmacology

Publication Date

2021-06-01

Document Type

Article

Disciplines

Cancer Biology | Enzymes and Coenzymes | Molecular Biology | Neoplasms

Abstract

FANCJ (BRIP1/BACH1) is a hereditary breast and ovarian cancer (HBOC) gene encoding a DNA helicase. Similar to HBOC genes, BRCA1 and BRCA2, FANCJ is critical for processing DNA inter-strand crosslinks (ICL) induced by chemotherapeutics, such as cisplatin. Consequently, cells deficient in FANCJ or its catalytic activity are sensitive to ICL-inducing agents. Unfortunately, the majority of FANCJ clinical mutations remain uncharacterized, limiting therapeutic opportunities to effectively use cisplatin to treat tumors with mutated FANCJ. Here, we sought to perform a comprehensive screen to identify FANCJ loss-of-function (LOF) mutations. We developed a FANCJ lentivirus mutation library representing approximately 450 patient-derived FANCJ nonsense and missense mutations to introduce FANCJ mutants into FANCJ knockout (K/O) HeLa cells. We performed a high-throughput screen to identify FANCJ LOF mutants that, as compared with wild-type FANCJ, fail to robustly restore resistance to ICL-inducing agents, cisplatin or mitomycin C (MMC). On the basis of the failure to confer resistance to either cisplatin or MMC, we identified 26 missense and 25 nonsense LOF mutations. Nonsense mutations elucidated a relationship between location of truncation and ICL sensitivity, as the majority of nonsense mutations before amino acid 860 confer ICL sensitivity. Further validation of a subset of LOF mutations confirmed the ability of the screen to identify FANCJ mutations unable to confer ICL resistance. Finally, mapping the location of LOF mutations to a new homology model provides additional functional information.

IMPLICATIONS: We identify 51 FANCJ LOF mutations, providing important classification of FANCJ mutations that will afford additional therapeutic strategies for affected patients.

Keywords

FANCJ, mutations, cancer

DOI of Published Version

10.1158/1541-7786.MCR-20-0828

Source

Calvo JA, Fritchman B, Hernandez D, Persky NS, Johannessen CM, Piccioni F, Kelch BA, Cantor SB. Comprehensive Mutational Analysis of the BRCA1-Associated DNA Helicase and Tumor-Suppressor FANCJ/BACH1/BRIP1. Mol Cancer Res. 2021 Jun;19(6):1015-1025. doi: 10.1158/1541-7786.MCR-20-0828. Epub 2021 Feb 22. PMID: 33619228; PMCID: PMC8178215. Link to article on publisher's site

Journal/Book/Conference Title

Molecular cancer research : MCR

Related Resources

Link to Article in PubMed

PubMed ID

33619228

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