Nicotinamide sensitizes human breast cancer cells to the cytotoxic effects of radiation and cisplatin

• Published in: Oncology reports Vol. 33; no. 2; pp. 721 - 728
• Main Authors: DOMÍNGUEZ-GÓMEZ, G, DÍAZ-CHÁVEZ, J, CHÁVEZ-BLANCO, A, GONZALEZ-FIERO, A, JIMÉNEZ-SALAZAR, J.E, DAMIÁN-MATSUMURA, P, GÓMEZ-QUIROZ, L.E, DUEÑAS-GONZÁLEZ, A
• Format: Journal Article
• Language: English
• Published: Greece D.A. Spandidos 01.02.2015; Spandidos Publications; Spandidos Publications UK Ltd
• Subjects: Apoptosis; BRCA1; BRCA1 Protein - genetics; Breast cancer; Breast Neoplasms - genetics; Breast Neoplasms - metabolism; Cancer; Cancer cells; Cancer therapies; Cell cycle; Cell Line, Tumor; Cell Proliferation - drug effects; Cell Proliferation - radiation effects; Cisplatin; Cisplatin - pharmacology; Cytotoxicity; Deoxyribonucleic acid; DNA; DNA Damage; DNA repair; Dosage and administration; Drug dosages; Drug resistance; Drug Synergism; Drug therapy; Female; Gene Expression Regulation, Neoplastic - drug effects; Gene Expression Regulation, Neoplastic - radiation effects; Humans; MCF-7 Cells; Mutation; Niacinamide; Niacinamide - pharmacology; niconamide; Oncology, Experimental; poly(ADP-ribose) polymerase; Poly(ADP-ribose) Polymerases - metabolism; Radiation therapy; Radiation, Ionizing; Rodents; Studies; United States > US
• ISSN: 1021-335X; 1791-2431
• DOI: 10.3892/or.2014.3661

Poly(ADP-ribose) polymerase (PARP) inhibitors enhance the effect of DNA alkylating agents on BRCA1- and BRCA2-deficient cell lines. The aim of this study was to analyze the effect of the PARP inhibitor nicotinamide (NAM) on breast cancer cells with different BRCA1 expression or function, such as BRCA1-deficient MDA-MB-436 cells, low expression BRCA1 MCF-7 cells, and the BRCA1 wild-type MDA-MB-231 cells, to demonstrate its effects as a chemo-or radiosensitizing agent. PARP activity was analyzed in MDA-MB-436, MCF-7 and MDA-MB-231 breast cancer cells subjected or not to NAM. Inhibition of PARP by NAM in the presence of DNA damage was examined by Alexa Fluor 488 immunofluorescence. Crystal violet assays were used to test growth inhibition and the chemo- and radiosensitization effects of NAM were investigated using clonogenic assays. Significant differences among data sets were determined using two-tailed ANOVA and Bonferroni tests. We demonstrated that NAM reduces PARP activity in vitro, and in cells subjected or not to DNA damage, it also reduces the viability of breast cancer cell lines and synergyzes the cytotoxicity of cisplatin in MDA-MB-436 and MCF-7 cells. Downregulation of PARP1 with siRNA led to modest growth inhibition, which was further increased by cisplatin. Nicotinamide also induced radiosensitization in MDA-MB-436 and MDA-MB-231 cells. In conclusion, NAM may be used as a chemo- or radiosensitizing agent regardless of the BRCA1 status in breast cancer.