Oestrogens and prostate cancer.

Abstract

Androgens are essential for stimulating normal development, growth and secretory activities of the prostate whereas oestrogens are generally regarded as inhibitors of growth. Evidence for the local synthesis of oestrogens includes the detection of aromatase mRNA and protein in the stroma of human non-malignant tissues and in malignant tissue, where it is detected in epithelial tumour cells. As well, aromatase activity was measured by biochemical assay and protein was detected in prostatic non-malignant and tumour cell lines. Taken together with the identification of direct oestrogenic actions on the prostate, these results suggest that alterations in local oestrogen synthesis may have significant consequences in malignancy of these organs.Genetically modified mouse models were studied in order to evaluate the action of oestrogens alone or in combination with androgens on the prostate gland. Hypogonadal (hpg) mice are deficient in gonadotrophins and androgens but showed direct proliferative responses to oestradiol. The responses were characterised by discrete lobe-specific changes including smooth-muscle regression, fibroblast proliferation, inflammation, and basal epithelial cell proliferation and metaplasia. The aromatase knockout (ArKO) mouse, deficient in oestrogens due to a non-functional aromatase enzyme, developed prostatic hyperplasia during the lifelong exposure to elevated androgens, however, no malignant changes were detected in the prostate at any time. In contrast, combined androgen and oestrogen treatment has been shown to induce prostatic dysplasia and adenocarcinoma. These results demonstrate that malignant changes to the prostate gland are dependent upon both androgenic and oestrogenic responses and that neither hormone alone is sufficient to evoke aberrant patterns of growth, resulting in malignancy.

The differential effects of prostate stromal cells derived from different zones on prostate cancer epithelial cells under the action of sex hormones

“…The period of development of PCa and BPH coincides with this elevation in the E2/ DHT ratio, indicating that the balance between the two hormonal factors may be critical to disease progression. 31 In our study, we utilized direct stromal-epithelial coculture models to demonstrate the influence of primary prostate stromal cells on the properties of metastatic PC3 cells under an increasing E2/DHT ratio. The growth-promoting effect of androgens on the epithelium during development is mediated through an AR-positive stroma.…”

The role of estrogens and estrogen receptors in normal prostate growth and disease

“…In addition, estrogens may be produced locally within the prostate via conversion of testosterone to 17β-estradiol by aromatase expressed within the prostate stroma [1,2], thus estrogen action in the prostate may occur independent of serum levels of this steroid.…”

Plasma estrone sulfate assay in men: Comparison of radioimmunoassay, mass spectrometry coupled to gas chromatography (GC–MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS)

“…Several tissues, whose prostate, contain the enzyme machinery required to convert E 1 S to E 2 [6]. Estrogens appear to be involved in the natural history of prostate cancer (PCa) [7][8][9][10][11]. We previously demonstrated an association between E 1 S and aggressive PCa [12].…”