Defective repair of oxidative dna damage in triple-negative breast cancer confers sensitivity to inhibition of poly(ADP-ribose) polymerase.
Subtypes of breast cancer that represent the two major types of epithelial cells in the breast (luminal and basal) carry distinct histopathologic profiles. Breast cancers of the basal-like subtype, which include the majority of hereditary breast cancers due to mutations in the breast cancer susceptibility gene 1 (BRCA1), frequently assume triple-negative status, i.e., they lack expression of estrogen receptor-alpha and progesterone receptor, and lack overexpression or amplification of the HER2/NEU oncogene. Defects in DNA damage response pathways result in genome instability and lead to carcinogenesis, but may also be exploited for therapeutic purposes. We analyzed repair of oxidative DNA damage by the base-excision repair (BER) pathway, which when aberrant leads to genomic instability and breast carcinogenesis, in cell lines that represent the different subtypes of breast cancer and in the presence of BRCA1 deficiency. We found that basal-like and BRCA1-mutated breast cancer cells were defective in BER of oxidative DNA damage, and that this defect conferred sensitivity to inhibition of poly(ADP-ribose) polymerase, a DNA repair enzyme. The defect may be attributed, at least in part, to a novel role for BRCA1 in the BER pathway. Overall, these data offer preventive, prognostic, and therapeutic usefulness.
Department of Medicine-Oncology, Stanford University School of Medicine, Stanford, California 94305, USA.
Elizabeth
E
Alli
Vandana B
VB
Sharma
Preethi
P
Sunderesakumar
James M
JM
Ford
D000818:Animals; D019313:BRCA1 Protein; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D045744:Cell Line, Tumor; D004249:DNA Damage; D045647:DNA Glycosylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004260:DNA Repair; D019398:Genes, BRCA1; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000235:genetics; D051379:Mice; D010084:Oxidation-Reduction; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases; D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human