Steroidogenic factor-1 regulates the rate of proliferation of normal and neoplastic rat ovarian surface epithelial cells in vitro.
Steroidogenic factor-1 (SF-1) is a transcription factor that is expressed by many cell types within the ovary and has been shown to inhibit granulosa cell proliferation. The present studies were designed to determine whether: 1) SF-1 is expressed by primary and transformed rat ovarian surface epithelial cells (i.e. ROSE cells); and 2) SF-1 expression effects the proliferation of both normal and neoplastic ROSE cells. These studies used immature, gonadotropin-primed and mature rat ovaries, as well as ROSE-179 cells from early passages (EP) and late passages (LP), T-sv-40 transformed ROSE cells, and T-ras transformed ROSE cells. In situ hybridization studies demonstrated that SF-1 was detected in the surface epithelium of rat ovaries, independent of age or gonadotropin treatment. Further, Northern blot and quantitative in situ hybridization studies revealed that significant amounts of SF-1 messenger RNA (mRNA) were present in EP-ROSE-179 cells but not in the other cell lines. Interestingly, EP-ROSE-179 cells proliferated at a significantly slower rate than the other cell lines. Further, SF-1 mRNA levels were higher in EP-ROSE-179 cells in the G0/G1 stage than in the S-, G2/M stage of the cell cycle. These observations suggest that a cause and effect relationship exists between the level of SF-1 expression and cell proliferation. To test this hypothesis, LP, T-sv-40, and T-ras ROSE cells were transfected with either control vector or SF-1 expression vector. Forty-eight hours after transfection, SF-1 expression was assessed by in situ hybridization, and the fold increase in cell number/24 h was determined. For each cell line, about 30% of the cells were successfully transfected. The fold increase in the number of cells observed after transfection with the SF-1 expression vector was significantly less than the increase in cell number after transfection with the control vector (P < 0.05). To confirm that the forced expression of SF-1 prevented proliferation, LP cells were cotransfected with a green fluorescent protein (GFP) expression vector and either control vector or SF-1 expression vector. This study demonstrated that virtually none of the GFP/SF-1-transfected cells proliferated over a 24-h period, whereas GFP/Control vector-transfected cells proliferated. Further, approximately 40% of the GFP/SF-1-transfected cells underwent apoptosis after 24 h of culture in serum-supplemented medium. These data demonstrate that: 1) normal ovarian surface epithelial cells express SF-1; 2) SF-1 is also expressed by EP-ROSE-179 cells, but its expression seems to be suppressed when the cells enter the cell cycle; 3) LP-, T-sv, and T-ras ROSE cells do not express SF-1 mRNA; and 4) the inability to express SF-1 is associated with an increase in cell proliferation. Finally, forced SF-1 expression interferes with serum-induced proliferation and leads to apoptosis.
Nash
D M
DM
Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington 06030, USA.
Hess
S A
SA
White
B A
BA
Peluso
J J
JJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology*; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D008938:Mitosis / Q000187:drug effects; D010051:Ovarian Neoplasms / Q000473:pathology*; D010053:Ovary / Q000166:cytology* / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear; D011988:Receptors, Thyroid Hormone / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011988:Receptors, Thyroid Hormone; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515060:steroidogenic factor 1, rat