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Updated: Oct 10, 2026
Silencing of BRCA2 to Identify Novel BRCA2-regulated Biological Functions in Cultured Human Cells
Published on: August 12, 2015
Increased cell survival by inhibition of BRCA1 using an antisense approach in an estrogen responsive ovarian
L A Annab1, R E Hawkins, G Solomon
1Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA. Annab@NIEHS.NIH.GOV
Abstract:
STATEMENT OF FINDINGS: We tested the hypothesis that BRCA1 may play a role in the regulation of ovarian tumor cell death as well as the inhibition of ovarian cell proliferation. Introduction of BRCA1 antisense retroviral constructs into BG-1 estrogen-dependent ovarian adenocarcinoma cells resulted in reduced BRCA1 expression. BRCA1 antisense pooled populations and derived subclones were able to proliferate in monolayer culture without estrogen, whereas control cells began to die after 10 days of estrogen deprivation. In addition, both populations and subclones of BRCA1 antisense infected cells demonstrated a growth advantage in monolayer culture in the presence of estrogen and were able to proliferate in monolayer culture without estrogen, while control cells did not. Furthermore, clonal studies demonstrated that reduced levels of BRCA1 protein correlated with growth in soft agar and greater tumor formation in nude mice in the absence of estrogen. These data suggest that reduction of BRCA1 protein in BG-1 ovarian adenocarcinoma cells may have an effect on cell survival during estrogen deprivation both in vitro and in vivo.
Insights
Reduced BRCA1 expression in ovarian cancer cells promotes cell survival and proliferation, even without estrogen. This suggests BRCA1
Area of Science:
- Molecular Biology
- Oncology
- Cell Biology
Background:
- The role of BRCA1 in ovarian tumor cell death and proliferation inhibition is not fully understood.
- Estrogen dependency is a key factor in the growth of certain ovarian adenocarcinoma cell lines.
Purpose of the Study:
- To investigate the hypothesis that BRCA1 regulates ovarian tumor cell death and proliferation.
- To determine the effect of reduced BRCA1 expression on estrogen-dependent ovarian cancer cells.
Main Methods:
- Introduction of BRCA1 antisense retroviral constructs into BG-1 estrogen-dependent ovarian adenocarcinoma cells.
- Assessment of BRCA1 expression levels.
- Evaluation of cell proliferation and survival under estrogen deprivation and presence.
- Soft agar growth assays and tumor formation studies in nude mice.
Main Results:
- BRCA1 antisense constructs successfully reduced BRCA1 expression in BG-1 cells.
- Reduced BRCA1 expression enabled cells to proliferate without estrogen, unlike control cells.
- BRCA1-deficient cells exhibited enhanced proliferation in the presence of estrogen and formed larger tumors in vivo without estrogen.
Conclusions:
- Reduction of BRCA1 protein in ovarian adenocarcinoma cells enhances cell survival during estrogen deprivation.
- BRCA1 may play a critical role in regulating ovarian cancer cell death and proliferation.
- Targeting BRCA1 could be a potential therapeutic strategy for ovarian cancer.
