Sphingosine kinase-1 activity and expression in human prostate cancer resection specimens.

PURPOSE: Sphingosine kinase-1 (SphK1) was shown in preclinical models and non-genitourinary cancers to be instrumental in cancer progression, adaptation to hypoxia and in tumour angiogenesis. No data were available in human prostate cancer. The present study was designed to assess SphK1 expression and activity in radical prostatectomy specimens and to research correlations with clinical features. MATERIALS AND METHODS: Transverse section of fresh tissue was obtained from 30 consecutive patients undergoing laparoscopic prostatectomy. SphK1 enzymatic activities of tumour and normal counterpart were determined. Relationships with PSA, Gleason sum, pathological stage, resection margin status and treatment failure were researched. SphK1 pattern of expression was then assessed on tissue microarray. RESULTS: A significant 2-fold increase in SphK1 enzymatic activity(11.1 ± 8.4 versus 5.9 ± 3.2 (P<0.04)) was observed in cancer. The upper quartile of SphK1 activity was associated with higher PSA (16.7 versus 6.4 ng/ml, P = 0.04), higher tumor volumes (20.7 versus 9.8, P = 0.002), higher rates of positive margins (85.7% versus 28.6%, P = 0.01) and surgical failure (71.4% versus 9.5%, P = 0.003) than the lower three quartiles. Odds ratios (OR) for treatment failure showed a strong relationship with SphK1 activity (OR: 23.7, P = 0.001), positive resection margins (OR: 15.0, P = 0.007) and Gleason sum (≥4+3, OR: 8.0, P = 0.003). Tissue microarrays showed discrete epithelial expression that varied with Gleason sum with significant relationship between SphK1 expression and higher Gleason sum. CONCLUSION: In complement to preclinical literature, the demonstrated relationships between SphK1-increased activity in cancer and relevant clinical features confirm a central role for SphK1 in prostate cancer that herald promising avenues in risk-assessment and treatment.

[Treatment of erectile dysfunction by phosphodiesterase-5 inhibitors and nonarteritic anterior ischemic optic neuropathy (NOIAN)]. / Traitement de la dysfonction erectile par les inhibiteurs de la phosphodiestérase-5 et troubles oculaires par neuropathie optique ischémique antérieure non artéritique (NOIAN).

INTRODUCTION: Following the notification of forty cases of varying degrees of vision loss in patients using phosphodiesterase-5 (PDE-5) inhibitors, the FDA (Food and Drug Administration) examined the possible link between these treatments of erectile dysfunction and NOIAN (nonarteritic anterior ischemic optic neuropathy). Following this investigation, the FDA requested modification of the summary of product characteristics (SPC) for this therapeutic category. The authors review this problem, especially in France. METHOD: The authors performed a search of the Pubmed database and the French Pharmacovigilance database. RESULTS: Since September 2006, 11 publications concerning 19 cases (14 with sildenafil and 2 with tadalafil) have been published. The mean age of these patients was 59.5 years (range: 42 to 69). Doses varied from 50 to 100 mg for sildenafil and 20 mg for tadalafil. Adverse effects (loss of visual acuity and decreased visual field) occurred between 30 min and 36 h after oral dosing. In 5 cases, treatment had been taken for more than one year. Ocular fundus examination showed papilloedema associated with several haemorrhages. Three patients presented a positive challenge. Several patients had a known risk factor for the development of NOIAN. One case was also reported to French Pharmacovigilance. DISCUSSION: The population with erectile dysfunction also often presents generalized endothelial disease, which also constitutes a risk factor for NOIAN. Although no cases of NOIAN were reported during the initial clinical trials, the rapid onset of NOIAN after the dose of PDE-5 inhibitor and several cases of positive challenge suggest a possible causal relationship with these drugs. The ocular action of PDE-5 inhibitors could be explained by a modification of retinal blood flow related to their pharmacological effects. CONCLUSION: The link between PDE-5 inhibitors and NOIAN has not been formally established. Before new studies are conducted to clarify this situation, practitioners must be aware of the potential ocular adverse effects related to the dose of PDE-5 inhibitors so that they can inform patients and notify any new cases. The SPCs of PDE-5 inhibitors were modified at the request of the FDA on 8 July 2005.

[Development and validation of a model of training at home to the laparoscopy]. / Mise au point et validation d'un modèle d'entraînement à domicile à la laparoscopie.

INTRODUCTION AND OBJECTIVES: Practice on a Pelvitrainer training is an essential part of the training of surgeons in laparoscopy. Most university departments are equipped with this type of model, but this equipment is expensive, cumbersome and often poorly accessible. The authors propose a new laparoscopy home training model and compare its performances with those of the reference training model. MATERIAL AND METHOD: The laparoscopy home training model is composed of a laptop computer; a Web Cam and a translucent plastic box. Ten operators with various levels of training were timed during 4 simple exercises performed on the home training model and were then timed when performing 6 interrupted sutures with this model and with a Pelvitrainer RESULTS: All operators successfully performed the proposed exercises. The mean operating time was correlated with the level of training (35 minutes versus 15 minutes for the 3 most experienced operators). The suture time was comparable with the home trainer (14 minutes) and the Pelvitrainer (13 minutes). The home training model is less expensive (75 euros), more accessible and easier to install (3 minutes) than the Pelvitrainer and can be used outside of medicalized structures. CONCLUSION: Trainee operators can practice laparoscopy at home. The manufacture of a Home-trainer requires simple material. The training capacities of this model are similar to those of a Pelvitrainer, but it is less cumbersome, less expensive and more readily available. This type of model could be used by each operator at home to improve his/her performances and to accelerate training.

Sphingosine kinase-1 as a chemotherapy sensor in prostate adenocarcinoma cell and mouse models.

Systemic chemotherapy was considered of modest efficacy in prostate cancer until the recent introduction of taxanes. We took advantage of the known differential effect of camptothecin and docetaxel on human PC-3 and LNCaP prostate cancer cells to determine their effect on sphingosine kinase-1 (SphK1) activity and subsequent ceramide/sphingosine 1-phosphate (S1P) balance in relation with cell survival. In vitro, docetaxel and camptothecin induced strong inhibition of SphK1 and elevation of the ceramide/S1P ratio only in cell lines sensitive to these drugs. SphK1 overexpression in both cell lines impaired the efficacy of chemotherapy by decreasing the ceramide/S1P ratio. Alternatively, silencing SphK1 by RNA interference or pharmacologic inhibition induced apoptosis coupled with ceramide elevation and loss of S1P. The differential effect of both chemotherapeutics was confirmed in an orthotopic PC-3/green fluorescent protein model established in nude mice. Docetaxel induced a stronger SphK1 inhibition and ceramide/S1P ratio elevation than camptothecin. This was accompanied by a smaller tumor volume and the reduced occurrence and number of metastases. SphK1-overexpressing PC-3 cells implanted in animals developed remarkably larger tumors and resistance to docetaxel treatment. These results provide the first in vivo demonstration of SphK1 as a sensor of chemotherapy.