Purification of activins from androgen-independent Shionogi carcinoma cells demonstrates enhanced expression of activin βB-subunit under androgen-depleted cell conditions in vitro and in vivo

✍ Scribed by Akira Tanaka; Yoshihisa Hasegawa; Yoji Hakamata; Tomoko Kamiakito; Ken Kuriki; Hiroki Yoshida; Masashi Fukayama

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 240 KB
• Volume: 188
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1109

✦ Synopsis

Abstract

Here, we report characterization of growth factors secreted from androgen‐independent mouse mammary Shionogi carcinoma cells. Previous isolation of fibroblast growth factor 8 (FGF8) from androgen‐dependent Shionogi carcinoma SC‐3 cells prompted us to characterize growth factors secreted from the androgen‐independent cells. After several purification procedures, mitogens for NIH3T3 cells from the androgen‐independent cells were identified as activins on the grounds that activin βA‐ and βB‐subunits are detected in the active fractions by Western blotting and that the growth‐promoting effects by the active fractions are specifically inhibited in the presence of follistatin. In addition, exogenous activins, but not inhibin, stimulated the growth of NIH3T3 cells in a dose‐dependent manner. Interestingly, transcripts of activin βB‐subunit were predominantly found in the androgen‐independent cells while its βA‐subunit was universally expressed in both androgen‐dependent and ‐independent Shionogi carcinoma cells. In concordant with this in vitro finding, transcripts of activin βB‐subunit were enhanced in murine prostates after castration. Therefore, expression of activin βB‐subunit, but not its βA‐subunit, is likely to be related with androgen‐depleted cell conditions in prostates, and possibly in androgen‐related cancers. © 2001 Wiley‐Liss, Inc.