Registered report: androgen receptor splice variants determine taxane sensitivity in prostate cancer.

The Prostate Cancer Foundation-Movember Foundation Reproducibility Initiative seeks to address growing concerns about reproducibility in scientific research by conducting replications of recent papers in the field of prostate cancer. This Registered Report describes the proposed replication plan of key experiments from "Androgen Receptor Splice Variants Determine Taxane Sensitivity in Prostate Cancer" by Thadani-Mulero and colleagues (2014) published in Cancer Research in 2014. The experiment that will be replicated is reported in Fig. 6A. Thadani-Mulero and colleagues generated xenografts from two prostate cancer cell lines; LuCaP 86.2, which expresses predominantly the ARv567 splice variant of the androgen receptor (AR), and LuCaP 23.1, which expresses the full length AR as well as the ARv7 variant. Treatment of the tumors with the taxane docetaxel showed that the drug inhibited tumor growth of the LuCaP 86.2 cells but not of the LuCaP 23.1 cells, indicating that expression of splice variants of the AR can affect sensitivity to docetaxel. The Prostate Cancer Foundation-Movember Foundation Reproducibility Initiative is a collaboration between the Prostate Cancer Foundation, the Movember Foundation and Science Exchange, and the results of the replications will be published by PeerJ.

Pharmacological and functional characterization of bradykinin B2 receptor in human prostate.

The objective of this study was to pharmacologically characterize bradykinin receptors, a component of the kallikrein-kinin system, in normal human prostate cells. In primary cultured human prostate stromal cells, bradykinin, but not [des-Arg9]bradykinin or [des-Arg10]kallidin, produced calcium mobilization or inositol phosphates accumulation with potencies (pEC50) of 8.8+/-0.2 and 8.2+/-0.2, respectively. This was consistent with abundance of bradykinin B2 mRNA over bradykinin B1 mRNA in prostate stromal cells. Although the prostate epithelial cells (prostate epithelium, BPH-1, and PC-3) expressed mRNA for bradykinin B2 receptors (albeit in lesser amounts than stromal cells), bradykinin was not functionally efficacious in the epithelial cells. Increasing concentrations of D-arginyl-L-arginyl-L-prolyl-trans-4-hydroxy-L-prolylglycyl-3-(2-thienyl)-L-alanyl-L-seryl-D-1,2,3,4-tetrahhydro-3-isoquinolinecarbonyl-L-(2alpha,3beta,7alphabeta)-octahydro-1H-indole-2-carbonyl-L-arginine (HOE-140), a bradykinin B2-selective peptide antagonist, attenuated bradykinin concentration-response curves in human prostate stromal cells with apparent estimate of affinity similar to that for the human bradykinin B2 receptor. Bradykinin (10 nM) caused proliferation of prostate stromal cells and phosphorylated extracellular signal-regulated kinases (ERK-1 and ERK-2) that were blocked by HOE-140 (1 microM). This study demonstrated that, in primary cultures of normal human prostate stromal cells, bradykinin activates bradykinin B2 receptors that may play a significant role in proliferation via activation of ERK-1/2 pathways.

P2X receptors and their role in female idiopathic detrusor instability.

PURPOSE: It is clear from previous studies that adenosine triphosphate is released as a contractile co-transmitter with acetylcholine from parasympathetic nerves supplying the mammalian bladder but the physiological significance of ligand gated purinergic P2X receptors in human bladder innervation has not been adequately investigated. We examined the role of these receptors in female patients with idiopathic detrusor instability. MATERIALS AND METHODS: Female patients with idiopathic detrusor instability were recruited for cystoscopy and bladder biopsy with ethics approval. Control tissue was obtained from age and sex matched patients with a urodynamically proved stable bladder. We obtained 4 bladder biopsies per patient from the posterior wall. Samples were analyzed in an organ bath for functional studies of the detrusor muscle to assess the purinergic contribution to its contraction. In addition, we performed quantitative analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical localization of P2X receptors. RESULTS: In patients with idiopathic detrusor instability detrusor P2X2 receptors were significantly elevated, while other P2X receptor subtypes were significantly decreased. A purinergic component of nerve mediated contractions was not detected in control female bladder biopsy specimens but there was a significant component in unstable bladder specimens. It was particularly prominent at stimulation frequencies of 2 to 16 Hz. which are likely to be most relevant physiologically. Approximately 50% of nerve mediated contractions were purinergic in idiopathic detrusor instability cases. CONCLUSIONS: In patients with idiopathic detrusor instability there is abnormal purinergic transmission in the bladder, which may explain symptoms. This pathway may be a novel target for the pharmacological treatment of overactive bladder.