Browsing by Subject "BRCA1 Protein"

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    Survival Benefit of Germline BRCA Mutation is Associated with Residual Disease in Ovarian Cancer.
    (Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology, 2018-01) Shi, Tingyan; Wang, Pan; Tang, Wenbin; Jiang, Rong; Yin, Sheng; Shi, Di; Wang, Qing; Wei, Qingyi; Zang, Rongyu
    BACKGROUND/AIMS:Prognostic value of germline BRCA1 or BRCA2 (gBRCA1/2) mutations in epithelial ovarian cancer (EOC) remains controversial, especially in the estimation of long-term survival. We previously reported the largest study of gBRCA1/2 mutation prevalence in Chinese EOC patients. The aim of this study is to further illustrate the correlation of residual disease and survival in BRCA-associated EOC in China. METHODS:In the current cohort consisting of 615 cases from the Chinese EOC genome-wide association study, we evaluated the association between gBRCA1/2 mutation and clinical outcomes. RESULTS:Overall, we did not find any significant difference between gBRCA1/2 mutation carriers and non-carriers in both progression-free survival (PFS) and overall survival (OS) (19.3 vs. 18.1 months and 77.2 vs. 73.2 months, P=0.528 and 0.147, HR 0.93 and 0.79, 95%CI 0.74-1.17 and 0.57-1.09, respectively). However, within three years after diagnosis, mutation carriers showed a longer OS than non-carriers (P=0.018, HR 0.53, 95%CI 0.31-0.90). Such a survival advantage decreased along with the extension of follow-up time. Quite interestingly, in the subgroup of patients with gross residual disease, mutation carriers had a longer survival than non-carriers (18.5 vs. 15.1 months and 68.5 vs. 54.3 months, P=0.046 and 0.038, HR 0.74 and 0.65, 95% CI 0.55-1.00 and 0.43-0.98, for PFS and OS respectively). CONCLUSIONS:Our findings provided the evidence that gBRCA1/2 mutation was not associated with survival in Chinese EOC patients, which possibly attributed to more than 37% of the patients without gross residual disease. Survival benefit of gBRCA1/2 mutation was prominent in ovarian cancer patients with gross residual disease.
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    Yeast screens identify the RNA polymerase II CTD and SPT5 as relevant targets of BRCA1 interaction.
    (PLoS One, 2008-01-16) Bennett, Craig B; Westmoreland, Tammy J; Verrier, Carmel S; Blanchette, Carrie AB; Sabin, Tiffany L; Phatnani, Hemali P; Mishina, Yuliya V; Huper, Gudrun; Selim, Alice L; Madison, Ernest R; Bailey, Dominique D; Falae, Adebola I; Galli, Alvaro; Olson, John A; Greenleaf, Arno L; Marks, Jeffrey R
    BRCA1 has been implicated in numerous DNA repair pathways that maintain genome integrity, however the function responsible for its tumor suppressor activity in breast cancer remains obscure. To identify the most highly conserved of the many BRCA1 functions, we screened the evolutionarily distant eukaryote Saccharomyces cerevisiae for mutants that suppressed the G1 checkpoint arrest and lethality induced following heterologous BRCA1 expression. A genome-wide screen in the diploid deletion collection combined with a screen of ionizing radiation sensitive gene deletions identified mutants that permit growth in the presence of BRCA1. These genes delineate a metabolic mRNA pathway that temporally links transcription elongation (SPT4, SPT5, CTK1, DEF1) to nucleopore-mediated mRNA export (ASM4, MLP1, MLP2, NUP2, NUP53, NUP120, NUP133, NUP170, NUP188, POM34) and cytoplasmic mRNA decay at P-bodies (CCR4, DHH1). Strikingly, BRCA1 interacted with the phosphorylated RNA polymerase II (RNAPII) carboxy terminal domain (P-CTD), phosphorylated in the pattern specified by the CTDK-I kinase, to induce DEF1-dependent cleavage and accumulation of a RNAPII fragment containing the P-CTD. Significantly, breast cancer associated BRCT domain defects in BRCA1 that suppressed P-CTD cleavage and lethality in yeast also suppressed the physical interaction of BRCA1 with human SPT5 in breast epithelial cells, thus confirming SPT5 as a relevant target of BRCA1 interaction. Furthermore, enhanced P-CTD cleavage was observed in both yeast and human breast cells following UV-irradiation indicating a conserved eukaryotic damage response. Moreover, P-CTD cleavage in breast epithelial cells was BRCA1-dependent since damage-induced P-CTD cleavage was only observed in the mutant BRCA1 cell line HCC1937 following ectopic expression of wild type BRCA1. Finally, BRCA1, SPT5 and hyperphosphorylated RPB1 form a complex that was rapidly degraded following MMS treatment in wild type but not BRCA1 mutant breast cells. These results extend the mechanistic links between BRCA1 and transcriptional consequences in response to DNA damage and suggest an important role for RNAPII P-CTD cleavage in BRCA1-mediated cancer suppression.