Evaluation of candidate biomarkers to predict cancer cell sensitivity or resistance to PARP-1 inhibitor treatment

• Published in: Cell cycle (Georgetown, Tex.) Vol. 11; no. 20; pp. 3837 - 3850
• Main Authors: Oplustilova, Lenka, Wolanin, Kamila, Mistrik, Martin, Korinkova, Gabriela, Simkova, Dana, Bouchal, Jan, Lenobel, Rene, Bartkova, Jirina, Lau, Alan, O'Connor, Mark J., Lukas, Jiri, Bartek, Jiri
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 15.10.2012; Landes Bioscience
• Subjects: 53BP1; Acid Anhydride Hydrolases; Antineoplastic Agents - pharmacology; Binding; Biology; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Bioscience; BRCA1; BRCA1 Protein - genetics; BRCA1 Protein - metabolism; BRCA2 Protein - genetics; BRCA2 Protein - metabolism; Calcium; Camptothecin - pharmacology; Cancer; cancer treatment; Carcinoma - drug therapy; Cell; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Line, Tumor; Cycle; DNA Damage; DNA damage response; DNA Repair Enzymes - genetics; DNA Repair Enzymes - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drug Resistance, Neoplasm - genetics; Enzyme Inhibitors - pharmacology; Female; Gamma Rays - therapeutic use; Gene Expression Regulation, Neoplastic; Genes, MDR; Humans; Intracellular Signaling Peptides and Proteins - antagonists & inhibitors; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Landes; Male; MRE11 Homologue Protein; MRN complex; Neoplasms - drug therapy; Neoplasms - genetics; Neoplasms - metabolism; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Organogenesis; PARP-1 inhibitor; parsylation; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases - genetics; Poly(ADP-ribose) Polymerases - metabolism; predictive biomarkers; Proteins; Recombinational DNA Repair - drug effects; Recombinational DNA Repair - radiation effects; synthetic lethality or viability; Tumor Suppressor p53-Binding Protein 1
• ISSN: 1538-4101; 1551-4005
• DOI: 10.4161/cc.22026

Impaired DNA damage response pathways may create vulnerabilities of cancer cells that can be exploited therapeutically. One such selective vulnerability is the sensitivity of BRCA1- or BRCA2-defective tumors (hence defective in DNA repair by homologous recombination, HR) to inhibitors of the poly(ADP-ribose) polymerase-1 (PARP-1), an enzyme critical for repair pathways alternative to HR. While promising, treatment with PARP-1 inhibitors (PARP-1i) faces some hurdles, including (1) acquired resistance, (2) search for other sensitizing, non-BRCA1/2 cancer defects and (3) lack of biomarkers to predict response to PARP-1i. Here we addressed these issues using PARP-1i on 20 human cell lines from carcinomas of the breast, prostate, colon, pancreas and ovary. Aberrations of the Mre11-Rad50-Nbs1 (MRN) complex sensitized cancer cells to PARP-1i, while p53 status was less predictive, even in response to PARP-1i combinations with camptothecin or ionizing radiation. Furthermore, monitoring PARsylation and Rad51 foci formation as surrogate markers for PARP activity and HR, respectively, supported their candidacy for biomarkers of PARP-1i responses. As to resistance mechanisms, we confirmed the role of the multidrug resistance efflux transporters and its reversibility. More importantly, we demonstrated that shRNA lentivirus-mediated depletion of 53BP1 in human BRCA1-mutant breast cancer cells increased their resistance to PARP-1i. Given the preferential loss of 53BP1 in BRCA-defective and triple-negative breast carcinomas, our findings warrant assessment of 53BP1 among candidate predictive biomarkers of response to PARPi. Overall, this study helps characterize genetic and functional determinants of cellular responses to PARP-1i and contributes to the search for biomarkers to exploit PARP inhibitors in cancer therapy.