Presence of activin signal transduction in normal ovarian cells and epithelial ovarian carcinoma

In this study, we have investigated the expression of inhibin subunits and activin receptors (ActRs) in normal and malignant ovarian cells. Each produ ct of the inhibin subunits (alpha, beta a, beta b) and activin receptors (A ctRs) amplified by reverse transcription polymerase chain reaction were det ected as a single band in human granulosa cells, surface epithelial cells ( OSE), and the ovarian cancer cell lines OVCAR 3 and SKOV 3. Western blot an alysis was performed using polyclonal antibodies against ActR IIa or IIb pe ptides based on 13 COOH-terminal amino acids; cultured human granulosa cell s were used as a positive control. Using ActR IIa antibody, one major band corresponding to approximately 80 kDa and one minor band corresponding to 1 05 kDa were observed in the samples. One single band at approximately 60 kD a was detected in OVCAR 3 and a 50 kDa band was detected with ActR IIb anti body in cultured granulosa cell, OSE and SKOV 3. Although no detectable cha nge was induced in Smad 4 mRNA in OVCAR 3, Smad 2 mRNA levels were increase d during 48 h treatment with activin A (50 ng ml(-1)). These data provide a better understanding as the first step in the mechanism of action of the a ctivin in the epithelial ovarian carcinoma. (C) 2000 Cancer Research Campai gn.