title: A novel crosstalk between BRCA1 and poly (ADP-ribose) polymerase 1 in breast cancer.
abstract: BRCA mutations are the main known hereditary factor for breast cancer. Notably, poly (ADP-ribose) polymerase 1 (PARP1) expression status plays a critical role in breast cancer progression and the clinical development of PARP1 inhibitors to treat BRCA-mutated breast cancer has advanced rapidly. However, dynamic crosstalk between BRCA1 and PARP1 remains largely unknown. Here, we showed that: (i) BRCA1 inactivation events (mutation, promoter methylation, or knockdown) were accompanied by increased PARP1 and nicotinamide adenine dinucleotide (NAD) levels, and a subsequent increase in NAD-dependent PARP1 activity in MDA-MB-231 and primary breast cancer cells; (ii) the overexpression of BRCA1 resulted in decreased PARP1 and NAD levels, and a subsequent impairment in NAD-dependent PARP1 activity in MDA-MB-231 and primary breast cancer cells; and (iii) intracellular NAD levels were largely responsible for regulating PARP1 activity in breast cancer cells, and NAD levels were positively correlated with PARP1 activity in human breast cancer specimens (R = 0.647, P < 0.001). Interestingly, the high efficiency of PARP1 triggered by BRCA1 inactivation may further inhibit BRCA1 transcription by NAD depletion. These results highlight a novel interaction between BRCA1 and PARP1, which may be beneficial for the dynamic balance between BRCA1 and PARP1-related biologic processes, especially for maintaining stable DNA repair ability. All of this may improve our understanding of the basic molecular mechanism underlying BRCA1- and PARP1-related breast cancer progression.
authors.affiliation: a Department of Obstetrics and Gynecology ; Shengjing Hospital of China Medical University ; Shenyang , China.
authors.forename: Da
authors.initials: D
authors.lastname: Li
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Bi
authors.forename: Na-Na
authors.initials: NN
authors.lastname: Chen
authors.forename: Ji-Min
authors.initials: JM
authors.lastname: Cao
authors.forename: Wu-Ping
authors.initials: WP
authors.lastname: Sun
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Zhou
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Li
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
mesh_terms: D019313:BRCA1 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D004260:DNA Repair; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D009154:Mutation; D009243:NAD / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D019313:BRCA1 Protein; D034741:RNA, Small Interfering; D009243:NAD; D011065:Poly(ADP-ribose) Polymerases
keywords: BRCA1; CtBP, C-terminal binding proteins; DMEM, Dulbecco's Modified Eagles Medium; DNA repair; ER, endoplasmic reticulum; ETS1, protein C-ets-1; NAD; NAD, nicotinamide adenine dinucleotide; Nampt, nicotinamide phosphoribosyltransferase; PARP1; PARP1, poly (ADP-ribose) polymerase 1; PCR, polymerase chain reaction; SD, standard deviations; TNBC, triple-negative breast cancer; breast cancer; shRNAs, short hairpin RNAs