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A new approach to prostate cancer
Y Z Ito1, Y Nakazato, V Petrow
1College of Medical Care and Technology, Gunma University, Department of Pathology, Gunma University School of Medicine, Japan.
Abstract:
Growth of androgen-dependent human prostatic adenocarcinoma implanted in the nude mouse (Honda tumour), is inhibited by 6-methyleneprogesterone. This steroid is a potent inhibitor of both rat and human prostatic 5 alpha-reductase in-vitro. In-vivo, at the studied dose level, it reduces metabolic conversion of testosterone to dihydrotestosterone with minimal effects upon circulating LH and testosterone. These data support the hypothesis that dihydrotestosterone and not testosterone is the main trophic androgen of the human prostatic neoplasm.
Insights
6-methyleneprogesterone inhibits human prostate cancer growth by blocking the conversion of testosterone to dihydrotestosterone. This suggests dihydrotestosterone is the key androgen driving prostate tumor progression.
Area of Science:
- Endocrinology
- Oncology
- Pharmacology
Background:
- Androgen-dependent human prostatic adenocarcinoma growth is a significant clinical challenge.
- Testosterone and dihydrotestosterone are key androgens regulating prostate function and neoplasia.
- Inhibitors of 5 alpha-reductase are potential therapeutic agents for prostate cancer.
Purpose of the Study:
- To investigate the effect of 6-methyleneprogesterone on androgen-dependent human prostatic adenocarcinoma growth in vivo.
- To determine the mechanism of action of 6-methyleneprogesterone, specifically its effect on 5 alpha-reductase activity and androgen levels.
Main Methods:
- Implantation of human prostatic adenocarcinoma (Honda tumour) in nude mice.
- Administration of 6-methyleneprogesterone.
- In vitro and in vivo assessment of 5 alpha-reductase inhibition.
- Measurement of circulating luteinizing hormone (LH) and testosterone levels.
Main Results:
- 6-methyleneprogesterone significantly inhibited the growth of the Honda tumour.
- The steroid demonstrated potent inhibition of both rat and human prostatic 5 alpha-reductase in vitro.
- In vivo, 6-methyleneprogesterone reduced the metabolic conversion of testosterone to dihydrotestosterone.
- Minimal effects were observed on circulating LH and testosterone levels.
Conclusions:
- Dihydrotestosterone, not testosterone, is the primary trophic androgen for human prostatic neoplasms.
- 6-methyleneprogesterone is a potential therapeutic agent for prostate cancer due to its ability to inhibit dihydrotestosterone synthesis.
- Targeting dihydrotestosterone production offers a promising strategy for managing androgen-dependent prostate cancer.