[BRCA1 regulates progesterone receptors A and B protein expressions in breast cancer cells in vitro].
OBJECTIVE
To study the regulatory role of BRCA1 in the expression of progesterone receptors A and B (PRA and PRB) in breast cancer cells.


METHODS
Breast cancer MCF-7 cells were transfected with pFlag-CMV2-BRCA1 wt plasmid containing a full-length BRCA1 cDNA or with BRCA1-specific siRNA via lipofectamine 2000 to induce overexpression or suppressed expression of BRCA1, respectively. Twenty-four hours after the transfection, the cells were incubated in fresh culture medium containing 100 nmol/L progesterone for 24 h. The total RNA extract or whole cell lysate was prepared for detecting BRCA1, PRA and PRB expressions using RT-PCR and Western blotting.


RESULTS
The protein expressions of PRA and PRB were significantly decreased whereas their mRNA expressions remained unchanged in MCF-7 cells overexpressing BRCA1. In MCF-7 cells with BRCA1 knock-down, in contrast, the PRA and PRB protein expressions were markedly increased.


CONCLUSIONS
In breast cancer cells, exogenous and endogenous BRCA1 can both down-regulate the expressions of PRA and PRB at the protein level.
Guo
Yin-xia
YX
Department of Cell Biology, Southern Medical University, Guangzhou 510515, China. guo81929@126.com
Zeng
Wei-sen
WS
Liu
Ya-wei
YW
Li
Yu-sheng
YS
Lin
Jun
J
Xiong
Jing-bo
JB
Luo
Shen-qiu
SQ
D019313:BRCA1 Protein / Q000096:biosynthesis / Q000235:genetics*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D019313:BRCA1 Protein; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011980:Receptors, Progesterone