Reduction of estrogen production by interleukin-6 in a human granulosa tumor cell line may have implications for endometriosis-associated infertility

• Published in: Fertility and sterility Vol. 83; no. 4; pp. 1086 - 1092
• Main Authors: Deura, Imari, Harada, Tasuku, Taniguchi, Fuminori, Iwabe, Tomio, Izawa, Masao, Terakawa, Naoki
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.2005; Elsevier Science
• Subjects: Antigens, CD - genetics; aromatase; Aromatase - metabolism; Biological and medical sciences; Birth control; Cell Line, Tumor; Cytokine Receptor gp130; Endometriosis; Endometriosis - metabolism; Endometriosis - physiopathology; Enzyme Activation - drug effects; Estradiol - metabolism; Estradiol - secretion; Female; Female genital diseases; granulosa cells; Gynecology. Andrology. Obstetrics; Humans; IL-6; infertility; Infertility, Female - metabolism; Infertility, Female - physiopathology; Interleukin-6 - genetics; Interleukin-6 - pharmacology; Luteal Cells - cytology; Luteal Cells - metabolism; Luteal Cells - secretion; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - physiology; Medical sciences; Membrane Glycoproteins - genetics; Non tumoral diseases; Receptors, Interleukin-6 - genetics; RNA, Messenger - analysis; Sterility. Assisted procreation; Endometriosis; granulosa cells; aromatase; infertility; IL-6; Human; Enzyme; Cytokine; Estrogen; Estrogen synthase; Sterility; Ovarian hormone; Female genital diseases; Interleukin 6; Granulosa cell; Cell line; Fertility; Established cell line; Uterine diseases; Sex steroid hormone; Tumor cell
• ISSN: 0015-0282; 1556-5653
• DOI: 10.1016/j.fertnstert.2004.12.014

To examine the effect of interleukin-6 (IL-6) on estrogen production and aromatase activity using a human granulosa tumor cell line (KGN cells). The involvement of the mitogen-activated protein kinase (MAPK) cascade in the inhibitory effects of IL-6 on estrogen production was also evaluated. Molecular and biological studies of KGN cells. Department of Obstetrics and Gynecology, Tottori University Hospital, Yonago, Japan. Gene expression of IL-6 and the IL-6 receptor was analyzed by reverse transcription–polymerase chain reaction and Southern blot analysis. KGN cells were cultured for 48 hours with IL-6 (0.1–10 ng/mL) or IL-6 (10 ng/mL) plus a mitogen activated protein kinase-extracellular signal regulated kinase kinase 1/2 (MEK1/2) inhibitor U0126 (10 μM). Estradiol concentration in the culture supernatants was measured by means of enzyme immunoassay, [1β- 3H] androstenedione was added to the cell lysate supernatant, and aromatase activity was determined by measuring the amount of [ 3H] H 2O released upon the conversion of [1β- 3H] androstenedione to estrone. To examine the activation of intracellular signal transduction molecules induced by IL-6, the phosphorylation of Stat3, p38 MAPK, and extracellular signal-regulated kinase 1/2 (ERK1/2) was examined by Western blotting. Gene expression of IL-6 and its receptor was detected in KGN cells. Estradiol secretion was significantly inhibited by adding IL-6, which also suppressed aromatase activity to 50% of the control. In addition, pretreatment with U0126 restored the IL-6–induced suppression of aromatase activity. IL-6 markedly enhanced the phosphorylation of ERK1/2, but not Stat3 and p38 MAPK. U0126 markedly reduced the level of the IL-6–induced phosphorylation of ERK1/2. These findings demonstrate that IL-6 may reduce estrogen production via the MAPK signal pathway in human granulosa cells. The results may support the notion that IL-6 is related to impaired estrogen biosynthesis in patients with endometriosis.