Androgen receptor inhibitory activity of dihydrocapsaicin: Insights from in vitro, in vivo and in silico studies

As a natural capsaicinoid from Capsicum annuum L., dihydrocapsaicin is well known for its anti-obesity property by reducing fat accumulation in adipose tissue. The androgen receptor (AR) is essential for both health and disease in humans and is the main focus for prostate cancer treatment. This study seeks to explore how dihydrocapsaicin inhibits the AR in human prostate cancer cell lines, aiming to offer a new natural product-derived AR inhibitor for the clinical management of prostate-related conditions. At first, it was observed that dihydrocapsaicin can induce proliferation suppression in human prostate cancer cells by hindering the cell cycle at the G0/G1 phase. In addition, dihydrocapsaicin probably inhibited AR activity by blocking its movement from the cytoplasm to the nucleus through binding to the AR-LBD, highlighting its potential as an effective inhibitor. From a mechanistic perspective, dihydrocapsaicin facilitated AR release from a stabilizing chaperone complex and enhanced its ubiquitination by E3 ligases, resulting in AR partial degradation via the ubiquitin-proteasome pathway. Our study on the molecular mechanisms behind dihydrocapsaicin's inhibitory effects on the AR revealed that it not only hindered the growth of prostate cancer cells but also reduced tumor growth in vivo. These results offer both experimental evidence and a theoretical basis for the thorough development of AR inhibitors, emphasizing dihydrocapsaicin's potential for application in functional foods or nutritional supplements targeting prostatic disorders.