Effect of small molecules modulating androgen receptor (SARMs) in human prostate cancer models.

Abstract

The management of hormone-refractory prostate cancer represents a major challenge in the therapy of this tumor, and identification of novel androgen receptor antagonists is needed to render treatment more effective. We analyzed the activity of two novel androgen receptor antagonists, (S)-11 and (R)-9, in in vitro and in vivo experimental models of hormone-sensitive or castration-resistant prostate cancer (CRPC). In vitro experiments were performed on LNCaP, LNCaP-AR, LNCaP-Rbic and VCaP human prostate cancer cells. Cytotoxic activity was assessed by SRB and BrdU uptake, AR transactivation by luciferase reporter assay and PSA levels by Real Time RT-PCR and ELISA assays. Cell cycle progression-related markers were evaluated by western blot. In vivo experiments were performed on SCID mice xenografted with cells with different sensitivity to hormonal treatment. In hormone-sensitive LNCaP and LNCaP-AR cells, the latter expressing high androgen receptor levels, (R)-9 and (S)-11 exhibited a higher cytotoxic effect compared to that of the reference compound ((R)-bicalutamide), also in the presence of the synthetic androgen R1881. Furthermore, the cytotoxic effect produced by (R)-9 was higher than that of (S)-11 in the two hormone-resistant LNCaP-AR and VCaP cells. A significant reduction in PSA levels was observed after exposure to both molecules. Moreover, (S)-11 and (R)-9 inhibited DNA synthesis by blocking the androgen-induced increase in cyclin D1 protein levels. In vivo studies on the toxicological profile of (R)-9 did not reveal the presence of adverse events. Furthermore, (R)-9 inhibited tumor growth in various in vivo models, especially LNCaP-Rbic xenografts, representative of recurrent disease. Our in vitro results highlight the antitumor activity of the two novel molecules (R)-9 and (S)-11, making them a potentially attractive option for the treatment of CRPC.

• Authors: Anna Tesei, Carlo Leonetti, Marzia Di Donato, Elisa Gabucci, Manuela Porru, Greta Varchi, Andrea Guerrini, Dino Amadori, Chiara Arienti, Sara Pignatta, Giulia Paganelli, Michele Caraglia, Gabriella Castoria, Wainer Zoli
• Journal: PloS one (PLoS One) Vol. 8 Issue 5 Pg. e62657 ( 2013) ISSN: 1932-6203 [Electronic] United States
• PMID: 23667504 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Androgen Receptor Antagonists
• DNA Primers
• Receptors, Androgen
• Luciferases
• Prostate-Specific Antigen
• Bromodeoxyuridine

Topics

• Active Transport, Cell Nucleus (drug effects)
• Analysis of Variance
• Androgen Receptor Antagonists (chemistry, pharmacology, toxicity)
• Animals
• Blotting, Western
• Bromodeoxyuridine
• COS Cells
• Cell Cycle (drug effects)
• Cell Line, Tumor
• Chlorocebus aethiops
• DNA Primers (genetics)
• Enzyme-Linked Immunosorbent Assay
• Fluorescent Antibody Technique
• Gene Expression Regulation (drug effects)
• Humans
• Luciferases
• Male
• Mice
• Mice, SCID
• Prostate-Specific Antigen (metabolism)
• Prostatic Neoplasms, Castration-Resistant (drug therapy)
• Protein Binding
• Real-Time Polymerase Chain Reaction
• Receptors, Androgen (metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Transcriptional Activation
• Transfection