The RNA helicase p68 is a novel androgen receptor coactivator involved in splicing and is overexpressed in prostate cancer

The androgen receptor (AR) is a member of the nuclear steroid hormone receptor family and is thought to play an important role in the development of both androgen-dependent and androgen-independent prostatic malignancy. Elucidating roles by which cofactors regulate AR transcriptional activity may provide therapeutic advancement for prostate cancer (PCa). The DEAD box RNA helicase p68 (Ddx5) was identified as a novel AR-interacting protein by yeast two-hybrid screening, and we sought to examine the involvement of p68 in AR signaling and PCa. The p68-AR interaction was verified by colocalization of overexpressed protein by immunofluorescence and confirmed in vivo by coimmunoprecipitation in the PCa LNCaP cell line. Chromatin immunoprecipitation in the same cell line showed AR and p68 recruitment to the promoter region of the androgen-responsive prostate-specific antigen (PSA) gene. Luciferase reporter, minigene splicing assays, and RNA interference (RNAi) were used to examine a functional role of p68 in AR-regulated gene expression, whereby p68 targeted RNAi reduced AR-regulated PSA expression, and p68 enhanced AR-regulated repression of CD44 splicing (P = 0.008). Tyrosine phosphorylation of p68 was found to enhance coactivation of ligand-dependent transcription of AR-regulated luciferase reporters independent of ATP-binding. Finally, we observe increased frequency and expression of p68 in PCa compared with benign tissue using a comprehensive prostate tissue microarray (P = 0.003; P = 0.008). These findings implicate p68 as a novel AR transcriptional coactivator that is significantly overexpressed in PCa with a possible role in progression to hormone-refractory disease.

Aberrant expression of extracellular signal-regulated kinase 5 in human prostate cancer

Abnormal intracellular signaling contributes to carcinogenesis and may represent novel therapeutic targets. mitogen/extracellular signal-regulated kinase kinase-5 (MEK5) overexpression is associated with aggressive prostate cancer. In this study, we examined the role of extracellular signal-regulated kinase (ERK5, an MAPK and specific substrate for MEK5) in prostate cancer. ERK5 immunoreactivity was significantly upregulated in high-grade prostate cancer when compared to benign prostatic hyperplasia (P<0.0001). Increased ERK5 cytoplasmic signals correlated closely with Gleason sum score (P<0.0001), bony metastases (P=0.0044) and locally advanced disease at diagnosis (P=0.0023), with a weak association with shorter disease-specific survival (P=0.036). A subgroup of patients showed strong nuclear ERK5 localization, which correlated with poor disease-specific survival and, on multivariant analysis, was an independent prognostic factor (P<0.0001). Analysis of ERK5 expression in matched tumor pairs (before and after hormone relapse, n=26) revealed ERK5 nuclear expression was significantly associated with hormone-insensitive disease (P=0.0078). Similarly, ERK5 protein expression was increased in an androgen-independent LNCaP subline. We obtained the following in vitro and in vivo evidence to support the above expression data: (1) cotransfection of ERK5wt and MEK5D constructs in PC3 cells results in predominant ERK5 nuclear localization, similar to that observed in aggressive clinical disease; (2) ERK5-overexpressing PC3 cells have enhanced proliferative, migrative and invasive capabilities in vitro (P<0.0001), and were dramatically more efficient in forming tumors, with a shorter mean time for tumors to reach a critical volume of 1000 mm(3), in vivo (P<0.0001); (3) the MEK1 inhibitor, PD184352, blocking ERK1/2 activation at low dose, did not suppress proliferation but did significantly decrease proliferation at a higher dose required to inhibit ERK5 activation. Taken together, our results establish the potential importance of ERK5 in aggressive prostate cancer.

The role of androgen in determining differentiation and regulation of androgen receptor expression in the human prostatic epithelium transient amplifying population

Abnormal differentiation in epithelial stem cells or their immediate proliferative progeny, the transiently amplifying population (TAP), may explain malignant pathogenesis in the human prostate. These models are of particular importance as differing sensitivities to androgen among epithelial cell subpopulations during differentiation are recognised and may account for progression to androgen independent prostate cancer. Androgens are crucial in driving terminal differentiation and their indirect effects via growth factors from adjacent androgen responsive stroma are becoming better characterised. However, direct effects of androgen on immature cells in the context of a prostate stem cell model have not been investigated in detail and are studied in this work. In alpha2beta1hi stem cell enriched basal cells, androgen analogue R1881 directly promoted differentiation by the induction of differentiation-specific markers CK18, androgen receptor (AR), PSA and PAP. Furthermore, treatment with androgen down-regulated alpha2beta1 integrin expression, which is implicated in the maintenance of the immature basal cell phenotype. The alpha2beta1hi cells were previously demonstrated to lack AR expression and the direct effects of androgen were confirmed by inhibition using the anti-androgen bicalutamide. AR protein expression in alpha2beta1hi cells became detectable when its degradation was repressed by the proteosomal inhibitor MG132. Stratifying the alpha2beta1hi cells into stem (CD133(+)) and transient amplifying population (TAP) (CD133(-)) subpopulations, AR mRNA expression was found to be restricted to the CD133(-) (TAP) cells. The presence of a functional AR in the TAP, an androgen independent subpopulation for survival, may have particular clinical significance in hormone resistant prostate cancer, where both the selection of immature cells and functioning AR regulated pathways are involved.

KGF suppresses α2β1 integrin function and promotes differentiation of the transient amplifying population in human prostatic epithelium

Prostate epithelial stem cells are self-renewing cells capable of differentiation into prostate epithelium, and are thought to contribute towards both benign and malignant conditions in the human prostate. We have previously demonstrated that prostate epithelial basal cells express high levels of integrin α2β1 and this population can be subdivided into stem (α2β1hi CD133+) and transient-amplifying population (TAP) cells (α2β1hi CD133-). However, the molecular mechanism(s) controlling the commitment and regulation of these cells towards differentiated epithelium remains unclear. Here, we demonstrate that β1 integrin function is required for the maintenance of basal prostatic epithelial cells and suppression of its function by either methylcellulose or, more specifically, β1-blocking antibody (80 μg/ml) induces differentiation, with associated expression of the differentiation-specific markers prostate acid phosphatase (PAP) and cytokeratin 18 (CK18). Keratinocyte growth factor (KGF), a stromal-derived growth factor, has previously been implicated in prostate organogenesis using in vitro tissue recombination experiments. We show that treatment with KGF (10 ng/ml) potently induces epithelial differentiation with concomitant suppression of α2β1 integrin expression as well as the induction of androgen receptor expression. Specifically, p38-MAPK appears to be involved and the presence of SB202190, a p38 inhibitor, significantly blocks KGF-induced differentiation. Furthermore, the expression of the high-affinity receptor tyrosine kinase to KGF (FGFR2) is predominantly detectable in α2β1hi CD133- TAP cells when compared with stem cells (α2β1hi CD133+), which would therefore be relatively unresponsive to the differentiating effect of KGF. Taken together, using a human primary culture model, we have demonstrated key roles for interactions between KGF and integrin-mediated function in the regulation of prostate epithelial differentiation.

Epigenetic inactivation of the human sprouty2 (hSPRY2) homologue in prostate cancer

Abnormal signalling events mediated by receptor tyrosine kinases (RTKs) contribute to human carcinogenesis. Sprouty2 (Spry2) is a key antagonistic regulator of RTK signalling and suppression of its expression or function may facilitate proliferation and angiogenesis. Using prostate cancer (CaP) as a model, we investigated the significance of Spry2 in human malignancy. We observed downregulated Spry2 expression in invasive CaP cell lines and high-grade clinical CaP (compared to benign prostatic hyperplasia (BPH) and well-differentiated tumours, P=0.041). A large CpG island is associated with hSPRY2, and extensive hypermethylation of this CpG island was observed in 76-82% of high-grade CaP, while control BPH tissues were predominantly unmethylated (P=0.0005). Furthermore, suppressed Spry2 expression correlated with methylation of the CpG region in clinical samples (P=0.004) and treatment with 5-aza-2'-deoxycytidine reactivated Spry2 expression in LNCaP and PC-3M cells. hSPRY2 maps to the long arm of chromosome 13 (13q31.1), where loss of heterozygosity (LOH) has been reported. We found no evidence of mutation; however, we demonstrated 27-40% LOH using flanking markers to hSPRY2. Hence, while biallelic epigenetic inactivation of hSPRY2 represents the main genetic event in prostate carcinogenesis, the observed 27-40% LOH presents evidence of hemizygous deletion with the remaining allele hypermethylated. We therefore propose hSPRY2 as a potential tumour suppressor locus in CaP.

A prospective audit of hypospadias correction in a regional paediatric surgery centre

AIM

To prospectively review the management and treatment of hypospadias in a single regional centre, and in particular, to assess the spectrum of cases treated, techniques used and to determine the nature of the complications.

METHODS

One hundred and fifty-three consecutive boys undergoing hypospadias repair during a 36-month period were included in the study. Information was collected prospectively and included the site of the urethral meatus, presence of chordee, surgical technique employed, use of urinary diversion, and the prescription of postoperative antibiotics and analgesics. Patients were assessed in the clinic following surgery at which time information on outcome and complications was obtained.

RESULTS

One hundred and fifty-seven procedures for hypospadias were performed. Single-stage reconstruction was performed in 145 boys. GRAP (glanular reconstruction and preputioplasty) repair was the most common operation employed (n=112). The overall fistula rate was 11.7 % with the majority of patients having a satisfactory functional and cosmetic outcome following surgery.

CONCLUSION

A variety of techniques can be employed to provide satisfactory correction of hypospadias with an increasing emphasis on single-stage day case procedures. GRAP repair is the favoured option for distal hypospadias and incorporates preservation of the prepuce.

Granulomatous mastitis can mimic breast cancer on clinical, radiological or cytological examination: a cautionary tale

In both women and men, breast lumps are the most common presentation of breast cancer. The following cases illustrate the pathological entity of granulomatous mastitis, which can present simulating breast cancer - including the first description of this condition in a male. These cases demonstrate the difficulty in clinical diagnosis and emphasizes that although there may be clues from the history, clinical awareness that this condition can mimic breast cancer in all aspects of the triple assessment process should arouse suspicion. The importance of histological diagnosis by core or excision biopsy is stressed, as with accurate diagnosis of granulomatous mastitis there is a mandate to avoid unnecessary surgery.

Fibroblast growth factor 17 is over-expressed in human prostate cancer

Over-expression of fibroblast growth factor 8 (FGF8) in human prostate cancer is associated with clinically aggressive disease. Among different members of the FGF family, FGF17 and FGF8 share high sequence homology and have similar patterns of expression during embryogenesis. In this study, the clinical significance of FGF17 expression and its in vitro function in prostate cancer cells were tested. Forty resected prostate specimens from patients with benign prostatic hyperplasia (BPH, n = 12) and prostate cancer (CaP, n = 28; Gleason sum scores 3-10) were studied using semi-quantitative RT-PCR. In addition, 85 cases of CaP (Gleason sum scores 5-9) and 20 cases of BPH were examined using immunohistochemistry and findings were correlated with clinical parameters. In vitro experiments using prostate cancer cell lines examined the functional significance of FGF17 in prostate cancer. These studies revealed a significant linear correlation between increasing Gleason sum scores and FGF17 expression using both immunohistochemistry (p < 0.0001, rho = 0.99) and RT-PCR (p = 0.008, rho = 0.99). Immunohistochemistry demonstrated upregulation of FGF17 in CaP compared with BPH (p < 0.0001) and, when comparing high-grade CaP (Gleason sum score 7-10) with BPH, RT-PCR showed a fourfold upregulation of FGF17 mRNA expression (p < 0.0001). Men with tumours displaying high levels of FGF17 expression had a worse outcome on survival analysis (p = 0.044) and a higher risk of progression with metastases (p < 0.0001). Proliferation assays showed low-dose recombinant (r) FGF17 (1 ng/ml) to be a more potent mitogen than rFGF1 and rFGF8 in prostate cancer cell lines (LNCaP, DU145, and PC3M) (p < 0.001). Furthermore, FGF8 was shown to induce expression of FGF17 in these cell lines. These data support a role for FGF17, and a model of co-expression of multiple FGFs, with FGF17 as a potential mediator of FGF8 function, in human prostate carcinogenesis.

The effects of sublingual glyceryl trinitrate on walking distance in patients with intermittent claudication. A randomised, doubled-blind, placebo-controlled, cross-over study

BACKGROUND

Intermittent claudication (IC) is a common problem in older age. New work shows that the administration of glyceryl trinitrate (GTN) can reduce the fall in ankle brachial pressure index (ABPI) after exercise and can increase maximum walking distance by 19% on treadmill exercise. The aim of this study was to further define the clinical benefits of GTN in patients with PVD.

METHODS

The study is of a randomised, double-blind, placebo-controlled cross-over design. We studied 29 patients with intermittent claudication where the median age was 67.5 years (45-84). This included 20 males and nine females, and six of these patients were diabetics. To be selected, the patients had to have a history of IC with a resting ABPI of 1.0 or less, that fell by more than 0.1 on exercise. Patients were walked for 15 min on flat ground following GTN spray or placebo and total distances walked were measured. This was then followed by the crossover component of the trial.

RESULTS

Median walking distance with placebo was 825 m (100-1300 m) and with GTN was 900 m (240-1400 m). This is an increase of 9% (p = 0.02, using the Wilcoxon matched pairs signed ranks test).

CONCLUSION

This study shows a statistically significant improvement in walking distance with GTN in patients with IC.

How to alter surgical practice? The use of guidelines to encourage day-case haemorrhoidectomy

BACKGROUND

Day case haemorrhoidectomy has been shown to be safe and acceptable to patients. The best way to introduce such evidence into clinical practice remains unclear: The aim is to assess the effectiveness of guidelines on the introduction of day-case haemorrhoidectomy in a general surgical unit.

METHODS

Prospective audit of day-case haemorrhoidectomy and retrospective review of in-patient procedures. The effectiveness of guidelines in encouraging day-case haemorrhoidectomy is assessed by analysis of avoidable admissions.

RESULTS

In the year prior to introduction of the guidelines 75 patients had elective haemorrhoidectomy, none as day-cases. In the year following the introduction of the guidelines 80 patients had elective haemorrhoidectomy, 35 (44%) as day cases. There were no complications or re-admissions. Of the 45 in-patients 31 (69%) were eligible for day surgery.

CONCLUSIONS

The establishment of clear guidelines and their dissemination results in significant changes in practice. However, audit has demonstrated that alternative strategies are needed to encourage changes in clinical practice.

Five-year audit of ambulatory 24-hour esophageal pH-manometry in clinical practice

BACKGROUND

Esophageal function testing was developed to aid diagnosis in patients with negative endoscopy. Although combined 24-h esophageal pH-manometry is now commercially available, its routine clinical effectiveness has not yet been studied.

METHODS

From 1992 to 1996 we evaluated 303 consecutive patients who were first-time referrals to our unit for 24-h esophageal pH-manometry. The referral indications were gastroesophageal reflux disease, 47.2%; dysphagia, 18.5%; non-cardiac chest pain, 14.9%; connective tissue disease, 13.2%; and symptomatic patients after antireflux surgery, 6.3%.

RESULTS

Overall, esophageal function testing altered the diagnosis of 44% of the patients, confirmed it in 38%, and specifically changed the management of 66%. The final clinical 'diagnosis' was reflux disease, 54% (32% with non-specific esophageal motility disorder); connective tissue disease, 9.9%; achalasia, 9.6%; other specific esophageal motility disorders, 3.3%; non-specific esophageal motility disorders, 6.9%; and normal, 16.2%. The cost per testing was estimated to be US$305 and per change in management US$465.

CONCLUSION

Combined 24-h pH-manometry has been shown to be a useful and cost-effective test for the management of selected patients in whom the primary investigation was insufficient.

Vascular surgical society of great britain and ireland: prospective randomized double-blind placebo-controlled crossover study to assess the effect of sublingual glyceryl trinitrate in patients with intermittent claudication

BACKGROUND: The effect of sublingual glyceryl trinitrate (GTN) on the claudication distance (CD) and maximum walking distance (MWD) of patients with intermittent claudication was assessed. METHODS: Inclusion criteria were: history of intermittent claudication; resting ankle : brachial pressure index (ABPI) of 1.00 or less; fall in ABPI of more than 0.1 following exercise; and patient not taking nitrates. In the first study 22 patients (median age 69 (range 60-73) years, 16 men, five diabetic, median resting ABPI 0.57 (range 0.1-0.64)) had their CD and MWD measured on a treadmill set at 3.2 km h-1 and 10 per cent gradient. They were then randomized to either GTN or placebo spray, and the distances were remeasured. The crossover portion of the study was then completed. In the second study 28 patients (median age 68 (range 45-84) years, 20 men, six diabetic, median resting ABPI 0.57 (range 0.13-0.98)) were randomized to either GTN or placebo and walked at their own pace along a flat corridor for 15 min. Following a rest of 15 min, the crossover portion of the study was completed. Statistical analysis was by the Wilcoxon matched pairs signed rank test. RESULTS: CONCLUSION: GTN can increase the MWD by 19 per cent when patients with intermittent claudication are walked on a treadmill and by 9 per cent when walking at their own pace on a flat gradient.