It is possible that small changes to a large number of androgen regulated genes is an important factor in the mechanism of action of the combination therapy, or that these cumulative changes are able to sensitize the prostate cancer cells to HDAC inhibition
September 5, 2021
It is possible that small changes to a large number of androgen regulated genes is an important factor in the mechanism of action of the combination therapy, or that these cumulative changes are able to sensitize the prostate cancer cells to HDAC inhibition. While the importance of enhanced blockade of androgen signaling by the combination treatment remains ambiguous, the expression data revealed that this treatment also modulates a multitude of other critical cellular processes. treatment. Depletion of IB Framycetin by siRNA knockdown enhanced apoptosis of prostate cancer cells, while ectopic overexpression of IB markedly suppressed cell death induced by the combination of bicalutamide and vorinostat. Conclusion These findings implicate IB as a key mediator of the apoptotic action of this combinatorial AR targeting strategy and a promising new therapeutic target Framycetin for Framycetin prostate cancer. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2188-2) contains supplementary material, which is available to authorized users. gene to produce more active or promiscuous forms of the receptor [9C14], altered levels of AR coregulators (reviewed in ), the expression of constitutively active AR splice variants [16C18], and adrenal and intratumoral biosynthesis of androgens [19C23], explain continued AR signaling during ADT. As many of these mechanisms are refractory to conventional ADT, there is considerable impetus to develop new and more potent agents targeting the androgen signaling axis. Two such agents are enzalutamide (MDV-3100), a novel AR antagonist that has demonstrated clinical activity in men who have failed both ADT and docetaxel-based chemotherapy , and abiraterone acetate, which targets an enzyme required for adrenal and intratumoral androgen biosynthesis. Phase III clinical trials demonstrated that these agents extend median survival of men with advanced CRPC by several months and both have received FDA approval . Despite the success of enzalutamide and abiraterone, it is accepted that treatment with these agents remains essentially palliative, and that combinatorial treatment strategies targeting multiple cellular pathways in addition to androgen signaling are more likely to improve outcomes for men with CRPC. One such combination therapy comprises the AR antagonist bicalutamide and the histone deacetylase (HDAC) inhibitor vorinostat, which act synergistically together to cause death of cell line models of prostate cancer . Vorinostat has a global effect on the acetylation of histones and other proteins within the cell but also reduces AR levels and activity and thereby directly targets androgen signaling . The aim of this study was to interrogate the molecular mechanisms underlying the synergistic action of bicalutamide and vorinostat in prostate cancer. Through expression profiling and functional studies, we identified (IB) as a critical mediator of this therapy, and in doing so provided novel insight into AR signaling and how this might be effectively targeted in prostate cancer. Methods Cells and Rabbit Polyclonal to OR52E2 reagents LNCaP human prostate cancer cells were purchased from the American Type Culture Collection (ATCC, Rockville, MD, USA), maintained in RPMI 1640 supplemented with 10?% fetal bovine serum (FBS) and used within a range of 20C40 passages. VCaP human prostate cancer cells were purchased from the ATCC, maintained in DMEM supplemented with sodium pyruvate, non-essential amino acids and 10?% FBS, and used within 60C70 passages. Vorinostat was obtained from Merck (New Jersey, USA) and dissolved in DMSO. Bicalutamide was obtained from Astra Zeneca (London, UK) and dissolved in ethanol. Cycloheximide was obtained from Sigma (St. Louis, MO, USA) and dissolved in DMSO. Anti-AR (N-20), anti-prostate specific antigen (PSA; Framycetin C-19) and anti-heat shock protein 90 (HSP90; H-114) antibodies were obtained from Santa Cruz Biotechnology (Santa Cruz, CA, USA). Anti-IB antibody was obtained from Cell Signaling Technology Inc (Danvers, MA, USA). Anti-tubulin antibody was obtained from Merck Millipore (Billerica, MA, USA). Horseradish peroxidase conjugated anti-rabbit, anti-mouse, and anti-sheep/goat secondary antibodies were obtained from DAKO (Botany, NSW, Australia). Non-specific, scrambled siRNA and ON-TARGETplus siRNAs targeting were purchased from Dharmacon (Lafayette, CO, USA) and the lentiviral ORF plasmid was purchased from GeneCopoeia (Rockville, MD,.