Elevated periprostatic androgens, sneaky testosterone and its implications.

A subset of men with prostate cancer have elevated periprostatic androgens compared with levels in peripheral blood (termed the sneaky T phenomenon), which are associated with poor clinical outcomes after radical prostatectomy. These androgens are of testicular origin and reach the prostate, presumably through venous shunting. Varicocele physiology is accompanied by increased hydrostatic pressure within the pelvic venous system, providing a theoretical mechanistic explanation for the sneaky T phenomenon. These observations suggest a potential role for varicocele in contributing to prostate cancer pathophysiology through sneaky T, which if proved, could be a further indication for varicocele repair. Sneaky T can help to explain the differences in the natural history of benign or malignant prostatic diseases between individuals and could be a tool when deciding on the therapeutic course to take.

Androgen loss weakens anti-tumor immunity and accelerates brain tumor growth.

Many cancers, including glioblastoma (GBM), have a male-biased sex difference in incidence and outcome. The underlying reasons for this sex bias are unclear but likely involve differences in tumor cell state and immune response. This effect is further amplified by sex hormones, including androgens, which have been shown to inhibit anti-tumor T cell immunity. Here, we show that androgens drive anti-tumor immunity in brain tumors, in contrast to its effect in other tumor types. Upon castration, tumor growth was accelerated with attenuated T cell function in GBM and brain tumor models, but the opposite was observed when tumors were located outside the brain. Activity of the hypothalamus-pituitary-adrenal gland (HPA) axis was increased in castrated mice, particularly in those with brain tumors. Blockade of glucocorticoid receptors reversed the accelerated tumor growth in castrated mice, indicating that the effect of castration was mediated by elevated glucocorticoid signaling. Furthermore, this mechanism was not GBM specific, but brain specific, as hyperactivation of the HPA axis was observed with intracranial implantation of non-GBM tumors in the brain. Together, our findings establish that brain tumors drive distinct endocrine-mediated mechanisms in the androgen-deprived setting and highlight the importance of organ-specific effects on anti-tumor immunity.

Chronic hypoxia stabilizes 3ßHSD1 via autophagy suppression.

Progression of prostate cancer depends on androgen receptor, which is usually activated by androgens. Therefore, a mainstay treatment is androgen deprivation therapy. Unfortunately, despite initial treatment response, resistance nearly always develops, and disease progresses to castration-resistant prostate cancer (CRPC), which remains driven by non-gonadal androgens synthesized in prostate cancer tissues. 3ß-Hydroxysteroid dehydrogenase/Δ5-->4 isomerase 1 (3ßHSD1) catalyzes the rate-limiting step in androgen synthesis. However, how 3ßHSD1, especially the "adrenal-permissive" 3ßHSD1(367T) that permits tumor synthesis of androgen from dehydroepiandrosterone (DHEA), is regulated at the protein level is not well understood. Here, we investigate how hypoxia regulates 3ßHSD1(367T) protein levels. Our results show that, in vitro, hypoxia stabilizes 3ßHSD1 protein by suppressing autophagy. Autophagy inhibition promotes 3ßHSD1-dependent tumor progression. Hypoxia represses transcription of autophagy-related (ATG) genes by decreasing histone acetylation. Inhibiting deacetylase (HDAC) restores ATG gene transcription under hypoxia. Therefore, HDAC inhibition may be a therapeutic target for hypoxic tumor cells.