Abstracts from the 1998 International Symposium on Biology of Prostate Growth

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 416 KB
• Volume: 38
• Category: Article
• ISSN: 0270-4137
• DOI: 10.1002/(sici)1097-0045(19990301)38:4<317::aid-pros8>3.0.co;2-1

✦ Synopsis

Inhibins and activins are dimeric proteins, composed of ␣ and ␤ subunits, which are members of the TGF␤ superfamily. In human ovarian cancer, serum levels of inhibin are elevated but the deletion of inhibin ␣ in mice results in tumour formation which implies that inhibin has tumour suppressive actions. The aim of this study was to determine if inhibin ␣ and activin ␤A and ␤B subunit gene expression was altered in men with high grade prostate cancer. The expression and localisation of ␣ and ␤ subunit mRNAs and proteins was examined in tissue sections from men with high grade prostate cancer using in situ hybridisation and immunostaining with specific antibodies to the subunits. A comparison was made between malignant and non malignant regions of tissue. Needle biopsies were obtained from a total of 46 men who were grouped according to histological diagnosis of BPH or prostate cancer (Gleason grade 4 or 5). The results demonstrate that the ␣ subunit is down regulated and there is no detectable expression or localisation of protein in poorly differentiated tumours. In contrast there was no corresponding loss in the expression or localisation of the ␤A or ␤B subunits; therefore the epithelial tumour tissue retains the capacity to synthesise activins, but not inhibins. Activins are known to inhibit IL-6 induced activities and suppress inflammatory responses which would effect the host defense; but some human prostate tumour cell lines are growth inhibited by activin. The latter effect is blocked by activin binding proteins, follistatins. We have previously reported that follistatin mRNA and protein production is