Exploring the tetrahydroisoquinoline thiohydantoin scaffold blockade the androgen receptor as potent anti-prostate cancer agents

Prostate cancer (PC) is a major cause of cancer-related male death in worldwide and the identification of new and improved potent anti-PC molecules is constantly required. A novel scaffold of tetrahydroisoquinoline thiohydantoin was rationally designed based on the enzalutamide structures and our pre-work, leading to the discovery of a series of new antiproliferative compounds. Several new analogues displayed improved androgen receptor (AR) antagonistic activity, while maintaining the higher selective toxicity toward LNCaP cells (AR-rich) versus DU145 cells (AR-deficient) compared to enzalutamide. In fact, compound 55 exhibited promising in vitro antitumor activity by impairing AR unclear translocation. More importantly, 55 showed better pharmacokinetic properties compared to the compound 1 reported in our pre-work. These results demonstrate a step towards the development of novel and improved AR antagonists.

Abiraterone acetate and prednisone in chemotherapy-naïve prostate cancer patients: rationale, evidence and clinical utility

Abiraterone acetate 1000 mg/day, combined with prednisone 5 mg PO twice daily, is indicated for the treatment of metastatic castration-resistant prostate cancer (mCRPC). Abiraterone acetate is the oral prodrug of abiraterone, a specific CYP17 inhibitor that blocks androgen biosynthesis within the adrenal glands, testes and tumor microenvironment. In a phase III trial of men with asymptomatic or minimally symptomatic, chemotherapy-naïve mCRPC, treatment with oral abiraterone acetate plus prednisone led to a statistically significant improvement in the co-primary endpoints of overall survival and radiographic progression-free survival when compared with placebo plus prednisone. In long-term follow-up of phase III trials, the incidence of corticosteroid-associated adverse events was 25.5% in the abiraterone acetate plus prednisone arm compared with 23.3% in the placebo plus prednisone arm. The need for regular patient monitoring and appropriate management of symptoms during long-term use of prednisone must be placed in context with the improvement in survival seen with abiraterone plus prednisone. Within the multidisciplinary environment that is emerging to meet quality and cost imperatives, abiraterone acetate plus prednisone is suitable for use in the chemotherapy-naïve population with minimal symptoms as well as in patients who have been treated with docetaxel and may have symptomatic disease. Ongoing trials are evaluating the role of abiraterone acetate plus prednisone in patients with nonmetastatic CRPC and metastatic hormone-sensitive prostate cancer, while further trials in the mCRPC setting are evaluating its use in combination regimens.

Enzalutamide: targeting the androgen signalling pathway in metastatic castration-resistant prostate cancer

Significant progress has been made in the understanding of the underlying cancer biology of castration‐resistant prostate cancer (CRPC) with the androgen receptor (AR) signalling pathway remaining implicated throughout the prostate cancer disease continuum. Reactivation of the AR signalling pathway is considered to be a key driver of CRPC progression and, as such, the AR is a logical target for therapy in CRPC. The objective of this review was to understand the importance of AR signalling in the treatment of patients with metastatic CRPC (mCRPC) and to discuss the clinical benefits associated with inhibition of the AR signalling pathway. A search was conducted to identify articles relating to the role of AR signalling in CRPC and therapies that inhibit the AR signalling pathway. Current understanding of prostate cancer has identified the AR signalling pathway as a logical target for the treatment of CRPC. Available therapies that inhibit the AR signalling pathway include AR blockers, androgen biosynthesis inhibitors, and AR signalling inhibitors. Enzalutamide, the first approved AR signalling inhibitor, has a novel mode of action targeting AR signalling at three key stages. The direct mode of action of enzalutamide has been shown to translate into clinical responses in patients with mCRPC. In conclusion, the targeting of the AR signalling pathway in patients with mCRPC results in numerous clinical benefits. As the number of treatment options increase, more trials evaluating the sequencing and combination of treatments are required. This review highlights the continued importance of targeting a key driver in the progression of CRPC, AR signalling, and the clinical benefits associated with inhibition of the AR signalling pathway in the treatment of patients with CRPC.