The sex discordance in COVID-19 outcomes has been widely recognized, with males generally faring worse than females and a potential link to sex steroids. A plausible mechanism is androgen-induced expression of TMPRSS2 and/or ACE2 in pulmonary tissues that may increase susceptibility or severity in males. This hypothesis is the subject of several clinical trials of anti-androgen therapies around the world. Here, we investigated the sex-associated TMPRSS2 and ACE2 expression in human and mouse lungs and interrogated the possibility of pharmacologic modification of their expression with anti-androgens. We found no evidence for increased TMPRSS2 expression in the lungs of males compared to females in humans or mice. Furthermore, in male mice, treatment with the androgen receptor antagonist enzalutamide did not decrease pulmonary TMPRSS2. On the other hand, ACE2 and AR expression was sexually dimorphic and higher in males than females. ACE2 was moderately suppressible with enzalutamide administration. Our work suggests that sex differences in COVID-19 outcomes attributable to viral entry are independent of TMPRSS2. Modest changes in ACE2 could account for some of the sex discordance.

325 Background: Abi, a potent inhibitor of 17α-hydroxylase/17,20-lyase (CYP17A1), is an oral treatment option for metastatic PCa in castration-resistant and -sensitive settings. Abi is converted to ∆4, 3-keto-abi (D4A) by 3β-hydroxysteroid dehydrogenase (3βHSD). D4A is further metabolized to multiple downstream steroidal metabolites including 3-keto-5α-Abi (5αA), which is an androgen receptor (AR) agonist and might affect response and/or resistance to Abi. The common HSD3B1(1245C) germline variant encodes for a 3βHSD missense that increases enzyme activity that allows tumors to utilize extragonadal androgens and is a predictive biomarker of resistance to ADT and sensitivity to CYP17A1 inhibition. However, the more active 3βHSD protein might increase 5αA synthesis, possibly limiting the clinical benefit of Abi. Methods: Blood was collected from CRPC pts on Abi and drug metabolites (MA) were extracted from serum, and analyzed by mass spectrometry. To correct for pharmacokinetics (PK) of time from last dose to blood draw in this cohort, data were normalized to the 8-hour time point of a separate PK study of Abi MAs and grouped by HSD3B1 genotype. HSD3B1 genotype was determined using germline DNA. Results: Abi MAs were evaluated in the sera of 30 CRPC pts on Abi. Abi, D4A, 5αA, were detectable in the sera of all pts. There were 8, 19, and 3 pts with homozygous wild-type, heterozygous, and homozygous variant HSD3B1 genotypes. HSD3B1 variant allele inheritance was associated with a statistically significant increase in 5αA concentrations, with highest concentration of 5αA MAs observed in homozygous variant HSD3B1 pts (Table). Conclusions: Germline HSD3B1 variant genotype is associated with higher 5αA metabolites with possible implications for AR stimulation and adverse clinical outcomes on Abi. [Table: see text]

157 Background: Prostate cancer is driven by androgen stimulation of the androgen receptor (AR). The next-generation AR antagonist, enzalutamide, prolongs progression-free and overall survival, but resistance and lethal disease eventually prevail. Emerging data suggest that the glucocorticoid receptor (GR) is upregulated in this context, stimulating expression of approximately 50% of genes normally stimulated by AR, thereby permitting continued growth despite AR blockade. However, countering this mechanism by administration of GR antagonists is problematic because GR is essential for life. Methods: We assessed the effects of enzalutamide on metabolism of cortisol to cortisone in the LAPC4 and VCaP models of prostate cancer using [3H]-cortisol and high performance liquid chromatography. Expression of 11β-hydroxysteroid dehydrogenase-2, encoding the enzyme 11βHSD2, which converts cortisol to cortisone, was assessed by immunoblot, in models of prostate cancer, tissues from patients treated with enzalutamide and prostate tissues treated exogenously with enzalutamide. The effect of shRNA knockdown of the AMFR ubiquitin E3-ligase on 11βHSD2 protein expression and enzyme activity was assessed. Finally, the potential therapeutic effects of 11βHSD2 re-expression on enzalutamide resistance was assessed in xenograft models. Results: Enzalutamide impedes inactivation of cortisol to cortisone, thereby sustaining tumor cortisol concentrations, permitting GR stimulation and enzalutamide resistance. Impeded cortisol inactivation by enzalutamide occurs by way of 11β-HSD2 expression loss in models of prostate cancer, prostate tissues from enzalutamide-treated patients and fresh prostatic tissues treated exogenously with enzalutamide. AMFR mediates loss of 11β-HSD2, which otherwise inactivates cortisol. Remarkably, reinstatement of 11β-HSD2 expression, or AMFR loss, reverses enzalutamide resistance in mouse xenograft tumors. Conclusions: Together, these findings reveal a surprising metabolic mechanism of enzalutamide resistance that may be targeted with a strategy that circumvents a requirement for systemic GR ablation.

No abstract

TPS155 Background: The common germline variant HSD3B1(1245C) encodes for a gain-of-function in 3βHSD1 which is associated with a shorter duration of response to androgen deprivation therapy (ADT) and more rapid disease progression to castration resistant PCa (CRPC) as shown previously in 5 independent cohorts. Therefore, evaluating the effect of such genotype variation on the level of steroid metabolites and the intratumoral dihydrotestosterone (DHT) concentration in benign and tumor tissue of men on ADT is of significant importance. We hypothesize that patients with homozygous HSD3B1 (1245C) genotype (HZ) will have a sustained androgen synthesis from extragonadal precursor steroids and higher concentrations of DHT compared to patients with wild-type HSD3B1 (1245A) (WT) inheritance in the context of testosterone suppression. In addition, it is expected that heterozygous HSD3B1 (1245C) patients (HTZ) will have intermediate levels of DHT. We also hypothesize that treatment with androgen receptor (AR) antagonist (apalutamide) will reverse the effects of elevated DHT on AR signaling in benign and malignant prostate tissue. Methods: In this Phase II trial (NCT02770391), men with newly diagnosed intermediate or high-risk PCa (GS ≥ 4+3, ≥cT2b, or PSA ≥ 10) who are scheduled to undergo radical prostatectomy (RP) will be enrolled into 3 groups based on their HSD3B1 genotype. All pts will receive one dose of 7.5 mg leuprolide injection and apalutamide 240 mg/day orally for 28 ± 3 days prior to RP. DHT and 7 other androgens (including testosterone, Dehydroepiandrosterone, Androstenedione) will be evaluated in the normal and malignant prostate tissue as well as serum samples obtained at the time of RP. AR regulated genes expression (including PSA, FKBP5, TMPRSS2) will be compared across 3 genotypes. A sample size of 57 pts (WT = 30, HTZ = 15, HZ = 12) will allow a statistical power of > 80% (with two-sided α = 0.05) to detect a 4-fold trend in DHT concentrations in the resected prostate tissue (primary endpoint) as well as similar trend in other androgens (secondary endpoint). As of Oct 2017, 16 of planned 57 pts have been enrolled. Clinical trial information: NCT02770391.