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Cruz C, Castroviejo-Bermejo M, Gutiérrez-Enríquez S, Llop-Guevara A, Ibrahim YH, Gris-Oliver A, Bonache S, Morancho B, Bruna A, Rueda OM, Lai Z, Polanska UM, Jones GN, Kristel P, de Bustos L, Guzman M, Rodríguez O, Grueso J, Montalban G, Caratú G, Mancuso F, Fasani R, Jiménez J, Howat WJ, Dougherty B, Vivancos A, Nuciforo P, Serres-Créixams X, Rubio IT, Oaknin A, Cadogan E, Barrett JC, Caldas C, Baselga J, Saura C, Cortés J, Arribas J, Jonkers J, Díez O, O'Connor MJ, Balmaña J, Serra V. RAD51 foci as a functional biomarker of homologous recombination repair and PARP inhibitor resistance in germline BRCA-mutated breast cancer. Ann Oncol 2018; 29:1203-1210. [PMID: 29635390 PMCID: PMC5961353 DOI: 10.1093/annonc/mdy099] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background BRCA1 and BRCA2 (BRCA1/2)-deficient tumors display impaired homologous recombination repair (HRR) and enhanced sensitivity to DNA damaging agents or to poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi). Their efficacy in germline BRCA1/2 (gBRCA1/2)-mutated metastatic breast cancers has been recently confirmed in clinical trials. Numerous mechanisms of PARPi resistance have been described, whose clinical relevance in gBRCA-mutated breast cancer is unknown. This highlights the need to identify functional biomarkers to better predict PARPi sensitivity. Patients and methods We investigated the in vivo mechanisms of PARPi resistance in gBRCA1 patient-derived tumor xenografts (PDXs) exhibiting differential response to PARPi. Analysis included exome sequencing and immunostaining of DNA damage response proteins to functionally evaluate HRR. Findings were validated in a retrospective sample set from gBRCA1/2-cancer patients treated with PARPi. Results RAD51 nuclear foci, a surrogate marker of HRR functionality, were the only common feature in PDX and patient samples with primary or acquired PARPi resistance. Consistently, low RAD51 was associated with objective response to PARPi. Evaluation of the RAD51 biomarker in untreated tumors was feasible due to endogenous DNA damage. In PARPi-resistant gBRCA1 PDXs, genetic analysis found no in-frame secondary mutations, but BRCA1 hypomorphic proteins in 60% of the models, TP53BP1-loss in 20% and RAD51-amplification in one sample, none mutually exclusive. Conversely, one of three PARPi-resistant gBRCA2 tumors displayed BRCA2 restoration by exome sequencing. In PDXs, PARPi resistance could be reverted upon combination of a PARPi with an ataxia-telangiectasia mutated (ATM) inhibitor. Conclusion Detection of RAD51 foci in gBRCA tumors correlates with PARPi resistance regardless of the underlying mechanism restoring HRR function. This is a promising biomarker to be used in the clinic to better select patients for PARPi therapy. Our study also supports the clinical development of PARPi combinations such as those with ATM inhibitors.
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Affiliation(s)
- C Cruz
- Experimental Therapeutics Group; High Risk and Familial Cancer, Vall d'Hebron Institute of Oncology, Barcelona; Department of Medical Oncology, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona
| | | | | | | | | | | | | | - B Morancho
- Growth Factors Laboratory, Vall d'Hebron Institute of Oncology, Barcelona, Spain
| | - A Bruna
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge
| | - O M Rueda
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge
| | - Z Lai
- AstraZeneca, Gatehouse Park, Waltham, USA
| | - U M Polanska
- DNA Damage Response Biology Area, Oncology iMed, AstraZeneca, Cancer Research UK Cambridge Institute, Cambridge, UK
| | - G N Jones
- DNA Damage Response Biology Area, Oncology iMed, AstraZeneca, Cancer Research UK Cambridge Institute, Cambridge, UK
| | - P Kristel
- Division of Molecular Pathology and Cancer Genomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | - R Fasani
- Molecular Oncology Group, Vall d'Hebron Institute of Oncology, Barcelona
| | - J Jiménez
- Molecular Oncology Group, Vall d'Hebron Institute of Oncology, Barcelona
| | - W J Howat
- DNA Damage Response Biology Area, Oncology iMed, AstraZeneca, Cancer Research UK Cambridge Institute, Cambridge, UK
| | | | | | - P Nuciforo
- Molecular Oncology Group, Vall d'Hebron Institute of Oncology, Barcelona
| | | | - I T Rubio
- Breast Surgical Unit, Breast Cancer Center, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona
| | - A Oaknin
- Department of Medical Oncology, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona; Gynecological Malignancies Group, Vall d'Hebron Institute of Oncology, Barcelona, Spain
| | - E Cadogan
- DNA Damage Response Biology Area, Oncology iMed, AstraZeneca, Cancer Research UK Cambridge Institute, Cambridge, UK
| | | | - C Caldas
- Department of Oncology and Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, UK; Cambridge Breast Unit, NIHR Cambridge Biomedical Research Centre and Cambridge Experimental Cancer Medicine Centre at Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - J Baselga
- Human Oncology and Pathogenesis Program (HOPP); Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, USA
| | - C Saura
- Department of Medical Oncology, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona; Breast Cancer and Melanoma Group, Vall d'Hebron Institute of Oncology, Barcelona
| | - J Cortés
- Ramón y Cajal University Hospital, Madrid; Vall d'Hebron Institute of Oncology, Barcelona
| | - J Arribas
- Growth Factors Laboratory, Vall d'Hebron Institute of Oncology, Barcelona, Spain; Department of Biochemistry and Molecular Biology, Building M, Campus UAB, Bellaterra (Cerdanyola del Vallès); Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona; CIBERONC, Barcelona
| | | | - O Díez
- Oncogenetics Group; Clinical and Molecular Genetics Area, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - M J O'Connor
- DNA Damage Response Biology Area, Oncology Innovative Medicine and Early Development Biotech Unit, AstraZeneca, Cambridge, UK
| | - J Balmaña
- High Risk and Familial Cancer, Vall d'Hebron Institute of Oncology, Barcelona; Department of Medical Oncology, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona
| | - V Serra
- Experimental Therapeutics Group; CIBERONC, Barcelona.
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