Cell-nonautonomous induction of ovarian and uterine serous cystadenomas in mice lacking a functional Brca1 in ovarian granulosa cells.
Women with germline mutations in BRCA1 have a 40% risk of developing ovarian cancer by age 70 and are also predisposed to cancers of the fallopian tubes. Given that ovulatory activity is a strong risk factor for sporadic ovarian cancer, we hypothesized that reduced BRCA1 expression might predispose to gynecological cancers indirectly, by influencing ovarian granulosa cells. These cells secrete sex steroids that control the ovulatory cycle and influence the growth of ovarian epithelial tumors. Granulosa cells also secrete mullerian inhibiting substance (MIS), a hormone that inhibits both the formation of female reproductive organs in male embryos and the proliferation of ovarian epithelial tumor cells. We tested this hypothesis by using the Cre-lox system to inactivate the Brca1 gene in mouse ovarian granulosa cells. A truncated form of the Fsh receptor promoter served as the Cre driver. Here, we show that indeed, inactivation of the Brca1 gene in granulosa cells led to the development of cystic tumors in the ovaries and uterine horns. These tumors carried normal Brca1 alleles, supporting the view that Brca1 may influence tumor development indirectly, possibly through an effector secreted by granulosa cells.
Chodankar
Rajas
R
Department of Pathology, University of Southern California/Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California 90033, USA.
Kwang
Stanford
S
Sangiorgi
Frank
F
Hong
Hao
H
Yen
Hai-Yun
HY
Deng
Chuxia
C
Pike
Malcolm C
MC
Shuler
Charles F
CF
Maxson
Robert
R
Dubeau
Louis
L
D000818:Animals; D018293:Cystadenoma, Serous / Q000235:genetics*; D017931:DNA Primers; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D020868:Gene Silencing; D019398:Genes, BRCA1; D006106:Granulosa Cell Tumor / Q000235:genetics*; D007150:Immunohistochemistry; D019426:Integrases / Q000235:genetics; D051379:Mice; D010051:Ovarian Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D011962:Receptors, FSH / Q000235:genetics; D019076:Transgenes / Q000235:genetics; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000235:genetics*
D017931:DNA Primers; D011962:Receptors, FSH; C045073:Cre recombinase; D019426:Integrases