Expression of Betaglycan, an Inhibin Coreceptor, in Normal Human Ovaries and Ovarian Sex Cord-Stromal Tumors and Its Regulation in Cultured Human Granulosa-Luteal Cells

• Published in: The journal of clinical endocrinology and metabolism 2003-10, Vol.88 (10), p.5002-5008
• Main Authors: Liu, Jianqi, Kuulasmaa, Tiina, Kosma, Veli-Matti, Bützow, Ralf, Vänttinen, Teemu, Hydén-Granskog, Christel, Voutilainen, Raimo
• Format: Article
• Language: English
• Subjects: Activins - metabolism; Biological and medical sciences; Cells, Cultured; Cyclic AMP-Dependent Protein Kinase Type II; Cyclic AMP-Dependent Protein Kinases - metabolism; Dinoprostone - pharmacology; Female; Female genital diseases; Follicle Stimulating Hormone - pharmacology; Gene Expression Regulation, Neoplastic - drug effects; Gynecology. Andrology. Obstetrics; Humans; Inhibins - metabolism; Luteal Cells - physiology; Luteinizing Hormone - pharmacology; Medical sciences; Ovarian Neoplasms - physiopathology; Oxytocics - pharmacology; Protein Kinase C - metabolism; Proteoglycans - genetics; Proteoglycans - metabolism; Receptors, Transforming Growth Factor beta - genetics; Receptors, Transforming Growth Factor beta - metabolism; Sex Cord-Gonadal Stromal Tumors - physiopathology; Tumors
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2003-030704

Activins and inhibins are often antagonistic in the regulation of ovarian function. TGFβ type III receptor, betaglycan, has been identified as a coreceptor to enhance the binding of inhibins to activin type II receptor and thus to prevent the binding of activins to their receptor. In this study we characterized the expression and regulation pattern of betaglycan gene in normal ovaries and sex cord-stromal tumors and in cultured human granulosa-luteal cells from women undergoing in vitro fertilization. Expression of betaglycan mRNA was detected by RT-PCR or Northern blotting in normal ovarian granulosa, thecal, and stroma cells as well as in granulosa-luteal cells. Immunohistochemical analysis revealed positive staining for betaglycan in antral and preovulatory follicular granulosa and thecal cells and in corpora lutea of normal ovaries. Furthermore, betaglycan expression was detected in the vast majority of granulosa cell tumors, thecomas, and fibromas, with weaker staining in granulosa cell tumors compared with fibrothecomas. In cultured granulosa-luteal cells, FSH and LH treatment increased dose-dependently the accumulation of betaglycan mRNA, as did the protein kinase A activator dibutyryl cAMP and the protein kinase C inhibitor staurosporine. In contrast, the protein kinase C activator 12-O-tetradecanoyl phorbol 13-acetate had no significant effect on betaglycan mRNA levels. Treatment with prostaglandin E2 and with its receptor EP2 subtype agonist butaprost increased betaglycan mRNA accumulation and progesterone secretion dose- and time-dependently. In summary, betaglycan gene is expressed in normal human ovarian steroidogenic cells and sex cord-stromal ovarian tumors. The accumulation of its mRNA in cultured granulosa-luteal cells is up-regulated by gonadotropins and prostaglandin E2, probably via the protein kinase A pathway. The specific expression and regulation pattern of betaglycan gene may be related to the functional antagonism of inhibins to activin signal transduction in human ovaries.