Androgen-dependent Human Prostate Cancer Cell Research Articles

Androgens regulate proliferation of human prostate cancer cells in culture by increasing transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF)/TGF-alpha receptor.

Androgens affect growth of the prostate gland and many prostate cancers. Androgens could mediate their mitogenic effects on prostate cells by an autocrine loop involving epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha that bind to the EGF/TGF-alpha receptor. We examined the effects of 5 alpha-dihydrotestosterone (DHT) and testosterone (T), EGF, and EGF-alpha on cell proliferation and 3H-thymidine incorporation in an androgen-dependent human prostate cancer cell line, ALVA101, in serum-free medium. The regulation of TGF-alpha and EGF/TGF-alpha receptor messenger RNA (mRNA) levels were determined by Northern blot analysis and EGF/TGF-alpha receptor protein by immunoblot. After 24 h of treatment of ALVA101 cells with DHT (10(-8) M) or T (10(-8) M), TGF-alpha mRNA levels increased 3- and 2.5-fold, respectively, and EGF/TGF-alpha receptor mRNA levels 2- and 1.5-fold, respectively. Cell numbers increased at day 5 in response to 10(-8) M DHT (18%, P < 0.01), 10(-8) M T (15%, P < 0.01), 20 ng/ml EGF (16%, P < 0.01), and 50 ng/mL TGF-alpha (34%, P < 0.01). DHT combined with TGF-alpha or T combined with EGF increased cell number 43% and 40% above control, respectively (P < 0.01 vs. DHT, P < 0.05 vs. TGF-alpha, T, EGF alone). The anti-EGF/TGF-alpha receptor antibody (528) blocked the cell proliferation induced by either DHT or TGF-alpha. We conclude that DHT and T stimulate synthesis of TGF-alpha and EGF/TGF-alpha receptor mRNAs and EGF/TGF-alpha receptor content in ALVA101 cells. This mitogenic effect of androgen on ALVA101 cells may involve TGF-alpha and the EGF/TGF-alpha receptor autocrine loop.

CDNA cloning of a human androgen-induced mRNA exhibiting an early and protein synthesis-independent induction

The detailed mechanism of action of androgens remains unknown. We have used an androgen-dependent human prostate cancer cell line and a subtractive cDNA hybridisation strategy to enrich for androgen-dependent sequences. This yielded a cDNA clone which exhibits the characteristics of a primary trans-activated target for androgens. This androgen-regulated gene encodes a polyadenylated 4.5 kb mRNA which is induced 30–50-fold within 3 h of treatment with 10 nM dihydrotestosterone. The induction does not require continued protein synthesis as it is maintained in the presence of protein synthesis inhibitors.