title: Detection of impaired homologous recombination repair in NSCLC cells and tissues.
abstract: BACKGROUND
  Homologous recombination repair (HRR) is a critical pathway for the repair of DNA damage caused by cisplatin or poly-ADP ribose polymerase (PARP) inhibitors. HRR may be impaired by multiple mechanisms in cancer, which complicates assessing the functional HRR status in cells. Here, we monitored the ability of non-small-cell lung cancer (NSCLC) cells to form subnuclear foci of DNA repair proteins as a surrogate of HRR proficiency.
  
  
  METHODS
  We assessed clonogenic survival of 16 NSCLC cell lines in response to cisplatin, mitomycin C (MMC), and the PARP inhibitor olaparib. Thirteen tumor explants from patients with NSCLC were subjected to cisplatin ex vivo. Cells were assayed for foci of repair-associated proteins such as BRCA1, FANCD2, RAD51, and γ-H2AX.
  
  
  RESULTS
  Four cell lines (25%) showed an impaired RAD51 foci-forming ability in response to cisplatin. Impaired foci formation correlated with cellular sensitivity to cisplatin, MMC and olaparib. Foci responses complemented or superseded genomic information suggesting alterations in the ATM/ATR and FA/BRCA pathways. Because baseline foci in untreated cells did not predict drug sensitivity, we adapted an ex vivo biomarker assay to monitor damage-induced RAD51 foci in NSCLC explants from patients. Ex vivo cisplatin treatment of explants identified two tumors (15%) exhibiting compromised RAD51 foci induction.
  
  
  CONCLUSIONS
  A fraction of NSCLC harbors HRR defects that may sensitize the affected tumors to DNA-damaging agents including PARP inhibitors. We propose that foci-based functional biomarker assays represent a powerful tool for prospective determination of treatment sensitivity, but will require ex vivo techniques for induction of DNA damage to unmask the underlying HRR defect.
authors: Laboratory of Cellular & Molecular Radiation Oncology, Department of Radiation Oncology, Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.
authors: Moritz
authors: M
authors: Birkelbach
authors: Natalie
authors: N
authors: Ferraiolo
authors: Liliana
authors: L
authors: Gheorghiu
authors: Heike N
authors: HN
authors: Pfäffle
authors: Benedict
authors: B
authors: Daly
authors: Michael I
authors: MI
authors: Ebright
authors: Cheryl
authors: C
authors: Spencer
authors: Carl
authors: C
authors: O'Hara
authors: Johnathan R
authors: JR
authors: Whetstine
authors: Cyril H
authors: CH
authors: Benes
authors: Lecia V
authors: LV
authors: Sequist
authors: Lee
authors: L
authors: Zou
authors: Jochen
authors: J
authors: Dahm-Daphi
authors: Lisa A
authors: LA
authors: Kachnic
authors: Henning
authors: H
authors: Willers
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D019313:BRCA1 Protein / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D002945:Cisplatin / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D008856:Microscopy, Fluorescence; D016685:Mitomycin / Q000494:pharmacology; D010793:Phthalazines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic / Q000235:genetics*; D059767:Recombinational DNA Repair / Q000187:drug effects / Q000235:genetics*; D014407:Tumor Cells, Cultured; D014410:Tumor Stem Cell Assay
chemical_list: D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; C499905:FANCD2 protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D010793:Phthalazines; D010879:Piperazines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D016685:Mitomycin; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D002945:Cisplatin; C531550:olaparib
references: Oncogene. 2004 Jan 29;23(4):1000-4
references: 14647419
references: Mol Cancer Res. 2009 Aug;7(8):1304-9
references: 19671671
references: Mol Cell Biol. 2004 Jan;24(2):708-18
references: 14701743
references: Cancer Lett. 2010 Jun 1;292(1):73-9
references: 20034732
references: Nature. 2008 Oct 23;455(7216):1069-75
references: 18948947
references: EMBO J. 2009 Nov 4;28(21):3413-27
references: 19779458
references: J Biomed Biotechnol. 2008;2008:821529
references: 18483568
references: Cancer Res. 1999 Aug 1;59(15):3547-51
references: 10446958
references: PLoS One. 2007 Nov 07;2(11):e1129
references: 17987116
references: Nucleic Acids Res. 2010 Mar;38(4):1061-70
references: 19942681
references: Clin Cancer Res. 2009 May 15;15(10):3344-53
references: 19401347
references: Int J Radiat Biol. 2009 Jun;85(6):523-31
references: 19466639
references: Nat Cell Biol. 2005 Feb;7(2):195-201
references: 15665856
references: Clin Cancer Res. 2010 Dec 15;16(24):6159-68
references: 20802015
references: Cancer Res. 2006 Aug 15;66(16):8109-15
references: 16912188
references: Mol Cell. 2001 Feb;7(2):249-62
references: 11239454
references: Clin Lung Cancer. 2005 Jan;6(4):250-4
references: 15694018
references: Proc Natl Acad Sci U S A. 2010 May 4;107(18):8352-6
references: 20404174
references: Cancer Cell. 2012 Jul 10;22(1):106-16
references: 22789542
references: J Thorac Oncol. 2007 Jun;2 Suppl 2:S68-76
references: 17589302
references: EMBO J. 2006 Dec 13;25(24):5775-82
references: 17124492
references: Cancer Discov. 2012 Nov;2(11):1036-47
references: 22915752
references: Nucleic Acids Res. 2009 Oct;37(19):6400-13
references: 19713438
references: Cytometry B Clin Cytom. 2009 Mar;76(2):79-90
references: 18727058