A potent new-scaffold androgen receptor antagonist discovered on the basis of a MIEC-SVM model.

Prostate cancer (PCa) is the second most prevalent malignancy among men worldwide. The aberrant activation of androgen receptor (AR) signaling has been recognized as a crucial oncogenic driver for PCa and AR antagonists are widely used in PCa therapy. To develop novel AR antagonist, a machine-learning MIEC-SVM model was established for the virtual screening and 51 candidates were selected and submitted for bioactivity evaluation. To our surprise, a new-scaffold AR antagonist C2 with comparable bioactivity with Enz was identified at the initial round of screening. C2 showed pronounced inhibition on the transcriptional function (IC50 = 0.63 µM) and nuclear translocation of AR and significant antiproliferative and antimetastatic activity on PCa cell line of LNCaP. In addition, C2 exhibited a stronger ability to block the cell cycle of LNCaP than Enz at lower dose and superior AR specificity. Our study highlights the success of MIEC-SVM in discovering AR antagonists, and compound C2 presents a promising new scaffold for the development of AR-targeted therapeutics.

Computationally guided discovery of novel non-steroidal AR-GR dual antagonists demonstrating potency against antiandrogen resistance.

As a major class of medicine for treating the lethal type of castration-resistant prostate cancer (PCa), long-term use of androgen receptor (AR) antagonists commonly leads to antiandrogen resistance. When AR signaling pathway is blocked by AR-targeted therapy, glucocorticoid receptor (GR) could compensate for AR function especially at the late stage of PCa. AR-GR dual antagonist is expected to be a good solution for this situation. Nevertheless, no effective non-steroidal AR-GR dual antagonist has been reported so far. In this study, an AR-GR dual binder H18 was first discovered by combining structure-based virtual screening and biological evaluation. Then with the aid of computationally guided design, the AR-GR dual antagonist HD57 was finally identified with antagonistic activity towards both AR (IC50 = 0.394 µM) and GR (IC50 = 17.81 µM). Moreover, HD57 could effectively antagonize various clinically relevant AR mutants. Further molecular dynamics simulation provided more atomic insights into the mode of action of HD57. Our research presents an efficient and rational strategy for discovering novel AR-GR dual antagonists, and the new scaffold provides important clues for the development of novel therapeutics for castration-resistant PCa.

Discovery of N-(4-(Benzyloxy)-phenyl)-sulfonamide Derivatives as Novel Antagonists of the Human Androgen Receptor Targeting the Activation Function 2.

Androgen receptor (AR) antagonists have been widely used for the treatment of prostate cancer (PCa). As a link between the AR and its transcriptional function, the activation function 2 (AF2) region has recently been revealed as a novel targeting site for developing AR antagonists. Here, we reported a series of N-(4-(benzyloxy)-phenyl)-sulfonamide derivatives as new-scaffold AR antagonists targeting the AR AF2. Therein, compound T1-12 showed excellent AR antagonistic activity (IC50 = 0.47 µM) and peptide displacement activity (IC50 = 18.05 µM). Furthermore, the in vivo LNCaP xenograft study confirmed that T1-12 offered effective inhibition on tumor growth when administered intratumorally. The study represents the first successful attempt to identify a small molecule targeting the AR AF2 with submicromolar AR antagonistic activity by structure-based virtual screening and provides important clues for the development of novel therapeutics for PCa treatment.

Discovery of novel antagonists targeting the DNA binding domain of androgen receptor by integrated docking-based virtual screening and bioassays.

Androgen receptor (AR), a ligand-activated transcription factor, is a master regulator in the development and progress of prostate cancer (PCa). A major challenge for the clinically used AR antagonists is the rapid emergence of resistance induced by the mutations at AR ligand binding domain (LBD), and therefore the discovery of novel anti-AR therapeutics that can combat mutation-induced resistance is quite demanding. Therein, blocking the interaction between AR and DNA represents an innovative strategy. However, the hits confirmed targeting on it so far are all structurally based on a sole chemical scaffold. In this study, an integrated docking-based virtual screening (VS) strategy based on the crystal structure of the DNA binding domain (DBD) of AR was conducted to search for novel AR antagonists with new scaffolds and 2-(2-butyl-1,3-dioxoisoindoline-5-carboxamido)-4,5-dimethoxybenzoicacid (Cpd39) was identified as a potential hit, which was competent to block the binding of AR DBD to DNA and showed decent potency against AR transcriptional activity. Furthermore, Cpd39 was safe and capable of effectively inhibiting the proliferation of PCa cell lines (i.e., LNCaP, PC3, DU145, and 22RV1) and reducing the expression of the genes regulated by not only the full-length AR but also the splice variant AR-V7. The novel AR DBD-ARE blocker Cpd39 could serve as a starting point for the development of new therapeutics for castration-resistant PCa.

Discovery of a Novel Androgen Receptor Antagonist Manifesting Evidence to Disrupt the Dimerization of the Ligand-Binding Domain via Attenuating the Hydrogen-Bonding Network Between the Two Monomers.

Androgen receptor (AR) has proved to be a vital drug target for treating prostate cancer. Here, we reported the discovery of a novel AR antagonist 92 targeting the AR ligand-binding pocket, but distinct from the marketed drug enzalutamide (Enz), 92 demonstrated inhibition on the AR ligand-binding domain (LBD) dimerization, which is a novel mechanism reported for the first time. First, a novel hit (26, IC50 = 5.57 µM) was identified through virtual screening based on a theoretical AR LBD dimer bound with the Enz model. Then, guided by molecular modeling, 92 was discovered with 32.7-fold improved AR antagonistic activity (IC50 = 0.17 µM). Besides showing high bioactivity and safety, 92 can inhibit AR nuclear translocation. Furthermore, 92 inhibited the formation of the AR LBD dimer, possibly through attenuating the hydrogen-bonding network between the two monomers. This interesting finding would pave the way for the discovery of a new class of AR antagonists.

Serum thymidine kinase 1 reflects the progression of pre-malignant and malignant tumors during therapy.

This study evaluated the clinical utility of serum thymidine kinase 1 (STK1) in following the progression of pre-malignancies and malignancies and in monitoring the response of common carcinomas to therapy within a routine clinical setting. The STK1 concentration levels of patients with malignancies (n=224), pre-malignancies (n=10), non-tumor/non-proliferating diseases (systemic lupus erythematosus, SLE) (n=53), benign tumors (n=20) and healthy volunteers (n=761) were determined by enhanced chemoluminescence dot blot assay. Prior to treatment, STK1 levels in the pre-malignant group alone (3.1±2.3) or in the pre-malignant and malignant groups together (2.3±1.9) were significantly higher than in the benign (1.4±0.8), SLE (1.1±0.8) or healthy volunteer (0.6±0.4) groups (p<0.01). According to ROC analysis, the STK1 assay provided a high degree of discrimination between STK1-positive pre-malignant (0.978) or pre-malignant + malignant (0.941) patients and STK1-negative healthy individuals. After varying treatments (surgery, chemotherapy, X-ray), STK1 levels increased by 40-50% during the first month, then decreased back to normal values or even lower. Following treatment, STK1 levels were significantly increased in squamous cell carcinoma (SCC) as compared to adenocarcinoma (AC) patients. In other types of malignancies, STK1 levels decreased from as early as the first month. The STK1 levels of relapsed treated patients were significantly higher (50-60%) than those of mid/long-term treated patients. In conclusion, the STK1 assay discriminated between patients with malignancies and healthy individuals very well, and is therefore potentially useful for a broad range of clinical applications. For example, it could be used for the evaluation of early tumor progression or of tumor progression during therapy in routine clinical settings, as well as for the screening of healthy individuals.