Novel Trifluoromethylated Enobosarm Analogues with Potent Antiandrogenic Activity In Vitro and Tissue Selectivity In Vivo

The antiandrogen enzalutamide downregulates TMPRSS2 and reduces cellular entry of SARS-CoV-2 in human lung cells

SARS-CoV-2 attacks various organs, most destructively the lung, and cellular entry requires two host cell surface proteins: ACE2 and TMPRSS2. Downregulation of one or both of these is thus a potential therapeutic approach for COVID-19. TMPRSS2 is a known target of the androgen receptor, a ligand-activated transcription factor; androgen receptor activation increases TMPRSS2 levels in various tissues, most notably prostate. We show here that treatment with the antiandrogen enzalutamide—a well-tolerated drug widely used in advanced prostate cancer—reduces TMPRSS2 levels in human lung cells and in mouse lung. Importantly, antiandrogens significantly reduced SARS-CoV-2 entry and infection in lung cells. In support of this experimental data, analysis of existing datasets shows striking co-expression of AR and TMPRSS2, including in specific lung cell types targeted by SARS-CoV-2. Together, the data presented provides strong evidence to support clinical trials to assess the efficacy of antiandrogens as a treatment option for COVID-19.

TMPRSS2 is regulated by androgen receptor signalling in the prostate, however it is unclear if blocking this signalling is beneficial in the context of SARS-CoV-2 lung infection. Here the authors show that antiandrogen treatment downregulates TMPRSS2 in the lung and reduces viral entry and infection.

Synthesis, biological evaluation and X-ray analysis of bicalutamide sulfoxide analogues for the potential treatment of prostate cancer

The androgen receptor (AR) is a pivotal target for the treatment of prostate cancer (PC) even when the disease progresses toward androgen-independent or castration-resistant forms. In this study, a series of sulfoxide derivatives were prepared and their antiproliferative activity evaluated in vitro against four different human prostate cancer cell lines (22Rv1, DU-145, LNCaP and VCap). Bicalutamide and enzalutamide were used as positive controls. Compound 28 displayed significant enhancement in anticancer activity across the four PC cell lines with IC₅₀ = 9.09 - 31.11 µM compared to the positive controls: bicalutamide (IC₅₀ = 45.20 -51.61 µM) and enzalutamide (IC₅₀ = 11.47 - 53.04 µM). Sulfoxide derivatives of bicalutamide were prepared efficiently from the corresponding sulfides using only one equivalent of mCPBA, limiting the reaction time to 15-30 min and maintaining the temperature at 0 °C. Interestingly, three pairs of sulfoxide diastereomers were separated and NMR comparison of their diastereotopic methylene (CH₂) group is presented. X-ray diffraction crystal structure analysis provided relative configuration assignment at the chiral sulfur and carbon centres. Molecular modelling study of the four diastereoisomers of compound 28 is described.

Synthesis and Biological Evaluation of Bicalutamide Analogues for the Potential Treatment of Prostate Cancer

The androgen receptor (AR) is a pivotal target for the treatment of prostate cancer (PC) even when the disease progresses toward androgen-independent or castration-resistant forms. In this study, a series of 15 bicalutamide analogues (sulfide, deshydroxy, sulfone, and O-acetylated) were prepared and their antiproliferative activity evaluated against four different human prostate cancer cell lines (22Rv1, DU-145, LNCaP, and VCap). Bicalutamide and enzalutamide were used as positive controls. Seven of these compounds displayed remarkable enhancement in anticancer activity across the four PC cell lines. The deshydroxy analogue (16) was the most active compound with IC₅₀ = 6.59-10.86 µM. Molecular modeling offers a plausible explanation of the higher activity of the sulfide analogues compared to their sulfone counterparts.

Evaluation of the effects of androgenic Chinese herbal medicines on androgen receptors and tumor growth in experimental prostate cancer models

ETHNOPHARMACOLOGICAL RELEVANCE

Many prostate cancer (PCa) patients in Mainland China and other Asian countries often use Chinese herbal medicines as an adjuvant treatment while receiving Western medicines. However, concerns have been raised about the potential herb-drug interaction when using herbal medicines containing phytoandrogens.

AIM OF THE STUDY

This study aimed to investigate the effects of the selected 21 Chinese herbal medicines on the proliferation and tumor growth using the relevant in vitro and in vivo models of PCa.

MATERIALS AND METHODS

After treatment of LNCaP and 22Rv1 cells with different concentrations of 70% ethanol extracts of the 21 selected herbal medicines for 48 h, the proliferative activity, the effects on androgen receptor (AR) and prostate specific antigen (PSA) were determined. The anti-tumor effects of the 21 herbs on PCa growth were also investigated on a subcutaneous mouse model of PCa.

RESULTS

The results showed that Epimedii Folium (EF) and Codonopsis Radix (CNR) could significantly increase the cell viability in LNCaP cells (p < 0.05 for both) and 22Rv1 cells (p < 0.05 for both), protein expressions of AR in LNCaP cells (p < 0.05 for both) and 22Rv1 cells (p < 0.05 for both), and PSA (p < 0.05 for both) in LNCaP cells. EF, CNR, and Cistanches Herba (CCH) markedly accentuated the tumor growth (p < 0.05 for three drugs) and AR expression (p < 0.05 for three herbs) in tumor tissues. On the other hand, treatment with Astragali Radix (AGR), Chuanxiong Rhizoma (CXR) and Bruceae Fructus (BF) significantly inhibited the cell viability in LNCaP cells (p < 0.05, p < 0.05 and p < 0.001, respectively) and in 22Rv1 cells (p < 0.05, p < 0.05 and p < 0.001, respectively), and the protein expression of AR in LNCaP cells (p < 0.05 for three herbs) and 22Rv1 cells (p < 0.05, p < 0.05 and p < 0.001, respectively), and the protein expression of PSA (p < 0.05 for three herbs) in LNCaP cells, as well as tumor growth (p < 0.05 for three herbs) and the AR expression (p < 0.05 for AGR and CXR, p < 0.001 for BF) in tumor tissues.

CONCLUSION

Our results revealed that AGR, CXR and BF suppressed the PCa development via inhibition of AR expression, while EF, CNR and CCH promoted the development and progression of PCa via enhancement of AR expression. The results strongly suggest that caution should be exercised when using androgenic Chinese herbal medicines in PCa patients.

AR mRNA stability is increased with AR-antagonist resistance via 3'UTR variants

Advanced prostate cancer is often treated with AR antagonists which target the androgen receptor (AR) on which the growth of the tumour depends. Prostate cancer often develops AR-antagonist resistance via a plethora of mechanisms, many of which are as yet unknown, but it is thought that AR upregulation or AR ligand-binding site mutations, may be responsible. Here we describe the production of cell lines based on LNCaP and VCaP, with acquired resistance to the clinically relevant AR antagonists, bicalutamide and enzalutamide. In these resistant cells, we observed, via RNA-seq, that new variants in the 3'UTR of the AR mRNA were detectable and that the levels were increased both with AR-antagonist treatment and with hormonal starvation. Around 20% of AR transcripts showed a 3 kb deletion within the 6.7 kb 3'UTR sequence. Actinomycin D and luciferase fusion studies indicated that this shorter mRNA variant was inherently more stable in anti-androgen-resistant cell lines. Of additional interest was that the AR UTR variant could be detected in the sera of prostate cancer patients in a cohort of serum samples collected from patients of Gleason grades 6-10, with an increasing level correlated to increasing grade. We hypothesise that the shorter AR UTR variant is a survival adaptation to low hormone levels and/or AR-antagonist treatment in these cells, where a more stable mRNA may allow higher levels of AR expression under these conditions.