Catherine Mazerolles

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.

Periprostatic adipocytes act as a driving force for prostate cancer progression in obesity

Obesity favours the occurrence of locally disseminated prostate cancer in the periprostatic adipose tissue (PPAT) surrounding the prostate gland. Here we show that adipocytes from PPAT support the directed migration of prostate cancer cells and that this event is strongly promoted by obesity. This process is dependent on the secretion of the chemokine CCL7 by adipocytes, which diffuses from PPAT to the peripheral zone of the prostate, stimulating the migration of CCR3 expressing tumour cells. In obesity, higher secretion of CCL7 by adipocytes facilitates extraprostatic extension. The observed increase in migration associated with obesity is totally abrogated when the CCR3/CCL7 axis is inhibited. In human prostate cancer tumours, expression of the CCR3 receptor is associated with the occurrence of aggressive disease with extended local dissemination and a higher risk of biochemical recurrence, highlighting the potential benefit of CCR3 antagonists in the treatment of prostate cancer.

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.

Activation of Sphingosine Kinase-1 in Cancer: Implications for Therapeutic Targeting

Sphingolipid metabolites are critical to the regulation of a number of fundamental biological processes including cancer. Whereas ceramide and sphingosine mediate and trigger apoptosis or cell growth arrest, sphingosine 1-phosphate promotes proliferation, cell survival and angiogenesis. The delicate equilibrium between the intracellular levels of each of these sphingolipids is controlled by the enzymes that either produce or degrade these metabolites. Sphingosine kinase-1 is a crucial regulator of this two-pan balance, because its produces the pro-survival and pro-angiogenic sphingosine 1-phosphate and decreases the amount of both ceramide and sphingosine, the pro-apoptotic sphingolipids. Moreover, its gene is oncogenic, its mRNA is overproduced in several solid tumors, its overexpression protects cells from apoptosis, and its activity is down-regulated by anti-cancer treatments. Therefore, the sphingosine kinase-1/sphingosine 1-phosphate signaling pathway appears to be a target of interest for therapeutic manipulation.

First Evidence of Sphingosine 1-Phosphate Lyase Protein Expression and Activity Downregulation in Human Neoplasm: Implication for Resistance to Therapeutics in Prostate Cancer

This is the first report of sphingosine 1-phosphate lyase (SPL) protein expression and enzymatic activity in human neoplasm. This enzyme drives irreversible degradation of sphingosine 1-phosphate (S1P), a bioactive lipid associated with resistance to therapeutics in various cancers, including prostate adenocarcinoma. In fresh human prostatectomy specimens, a remarkable decrease in SPL enzymatic activity was found in tumor samples, as compared with normal adjacent tissues. A significant relationship between loss of SPL expression and higher Gleason score was confirmed in tissue microarray (TMA) analysis. Moreover, SPL protein expression and activity were inversely correlated with those of sphingosine kinase-1 (SphK1), the enzyme producing S1P. SPL and SphK1 expressions were independently predictive of aggressive cancer on TMA, supporting the relevance of S1P in prostate cancer. In human C4-2B and PC-3 cell lines, silencing SPL enhanced survival after irradiation or chemotherapy by decreasing expression of proteins involved in sensing and repairing DNA damage or apoptosis, respectively. In contrast, enforced expression of SPL sensitized cancer cells to irradiation or docetaxel by tilting the ceramide/S1P balance toward cell death. Interestingly, the S1P degradation products failed to sensitize to chemo- and radiotherapy, supporting the crucial role of ceramide/S1P balance in cancer. Of note, the combination of SPL enforced expression with a SphK1 silencing strategy by further decreasing S1P content made prostate cancer cells even more sensitive to anticancer therapies, suggesting that a dual strategy aimed at stimulating SPL, and inhibiting SphK1 could represent a future approach to sensitize cancer cells to cancer treatments. Mol Cancer Ther; 11(9); 1841–51. ©2012 AACR.

Prognostic Interest in Discriminating Muscularis Mucosa Invasion (T1a vs T1b) in Nonmuscle Invasive Bladder Carcinoma: French National Multicenter Study with Central Pathology Review

PURPOSE Predictive factors of T1 nonmuscle invasive bladder cancer evolution that could guide treatment decision making are lacking. We assessed the prognostic value of muscularis mucosa invasion in nonmuscle invasive bladder cancer. MATERIALS AND METHODS In a national multicenter study patients with primary T1 nonmuscle invasive bladder cancer were recruited from 6 French hospitals. All patients had undergone transurethral resection of bladder tumor. All T1 tumors were substaged according to muscularis mucosa invasion as T1a-no invasion beyond the muscularis mucosa or T1b-invasion beyond the muscularis mucosa with muscle preservation. Subsequent central pathology review was then done by a single referent uropathologist. Muscularis mucosa invasion was tested as a prognostic factor for survival on univariate and multivariate analysis. RESULTS A total of 587 patients were enrolled in the study, including 388 (66%) with T1a and 199 (34%) with T1b tumors. Median followup after transurethral resection of bladder tumor was 35 months (IQR 14-54). There was no significant difference between groups T1a and T1b except high tumor grade in T1b cases (p <0.0001). After central review, initial pathological substaging was confirmed in 84% of cases. On multivariate analysis muscularis mucosa invasion (T1b substage) was significantly associated with recurrence-free (p = 0.03), progression-free (p = 0.0002) and cancer specific (p = 0.02) survival. The main study limitation was absent systematic subsequent transurethral resection of bladder tumor. CONCLUSIONS Muscularis mucosa invasion appears to be highly predictive of T1 nonmuscle invasive bladder cancer behavior. Consequently, systematic T1a vs T1b discrimination should be highly advocated by urologists and pathologists. We believe that it could aid in crucial decision making when choosing between conservative management and radical cystectomy remains a moot point.

Sphingosine Kinase-1 Is Central to Androgen-Regulated Prostate Cancer Growth and Survival

Background Sphingosine kinase-1 (SphK1) is an oncogenic lipid kinase notably involved in response to anticancer therapies in prostate cancer. Androgens regulate prostate cancer cell proliferation, and androgen deprivation therapy is the standard of care in the management of patients with advanced disease. Here, we explored the role of SphK1 in the regulation of androgen-dependent prostate cancer cell growth and survival. Methodology/Principal Findings Short-term androgen removal induced a rapid and transient SphK1 inhibition associated with a reduced cell growth in vitro and in vivo, an event that was not observed in the hormono-insensitive PC-3 cells. Supporting the critical role of SphK1 inhibition in the rapid effect of androgen depletion, its overexpression could impair the cell growth decrease. Similarly, the addition of dihydrotestosterone (DHT) to androgen-deprived LNCaP cells re-established cell proliferation, through an androgen receptor/PI3K/Akt dependent stimulation of SphK1, and inhibition of SphK1 could markedly impede the effects of DHT. Conversely, long-term removal of androgen support in LNCaP and C4-2B cells resulted in a progressive increase in SphK1 expression and activity throughout the progression to androgen-independence state, which was characterized by the acquisition of a neuroendocrine (NE)-like cell phenotype. Importantly, inhibition of the PI3K/Akt pathway—by negatively impacting SphK1 activity—could prevent NE differentiation in both cell models, an event that could be mimicked by SphK1 inhibitors. Fascinatingly, the reversability of the NE phenotype by exposure to normal medium was linked with a pronounced inhibition of SphK1 activity. Conclusions/Significance We report the first evidence that androgen deprivation induces a differential effect on SphK1 activity in hormone-sensitive prostate cancer cell models. These results also suggest that SphK1 activation upon chronic androgen deprivation may serve as a compensatory mechanism allowing prostate cancer cells to survive in androgen-depleted environment, giving support to its inhibition as a potential therapeutic strategy to delay/prevent the transition to androgen-independent prostate cancer.

Mannose-6-Phosphate Receptor: A Target for Theranostics of Prostate Cancer†

The development of personalized and non-invasive cancer therapies based on new targets combined with nanodevices is a major challenge in nanomedicine. In this work, the over-expression of a membrane lectin, the cation-independent mannose 6-phosphate receptor (M6PR), was specifically demonstrated in prostate cancer cell lines and tissues. To efficiently target this lectin a mannose-6-phosphate analogue was synthesized in six steps and grafted onto the surface of functionalized mesoporous silica nanoparticles (MSNs). These MSNs were used for in vitro and ex vivo photodynamic therapy to treat prostate cancer cell lines and primary cell cultures prepared from patient biopsies. The results demonstrated the efficiency of M6PR targeting for prostate cancer theranostic.

Ureteral stenosis as the sole manifestation of Wegener's granulomatosis.

In Wegeners granulomatosis, necrotizing lesions are typically located in the upper and lower respiratory tract and kidneys, and ureteral involvement is uncommon. We report 2 cases in which intrinsic ureteral stenosis was the sole manifestation of this small-vessel vasculitis. Excisional surgery evidenced characteristic granulomatous inflammation that allowed adjuvant elective medical treatment. Urologists, nephrologists, and internists should be aware of this atypical presentation of Wegeners granulomatosis. Thorough clinical and biologic assessments are warranted in the initial workup of isolated intrinsic ureteral stenosis.

PURE SEMINOMA IN A MALE PHENOTYPE 46,XX TRUE HERMAPHRODITE

A 56-year-old man was referred to us for chronic abdominal pain. Physical examination revealed a firm mass in the right upper quadrant of the abdomen, gynecomastia and penile chordee. Exploration for crytorchidism when the patient was 31 years old failed to identify testicles and 2 prostheses had been inserted in the scrotum. Computerized tomography (CT) guided biopsies of the 6 3 8 3 10 cm. mass demonstrated pure seminoma. A moderate increase in serum b-human chorionic gonadotropin (15 IU/l., normal male less than 4), and normal levels of a-fetoprotein and carcinoembryonic antigen were consistent with the diagnosis. The seminoma was believed to be in an ectopic gonad. At surgery 2 pedicles originating from the superior mesenteric artery and right renal artery were identified, and the tumor was excised (fig. 1, A). Exploration on the left side revealed a 3 3 2 cm. mass beside the left colic flexure and 2 adjacent 10 mm. nodules (fig. 2, A). Pelvic exploration, secondary cystourethrography and cystoscopy were consistent with the male phenotype. Pathological examination confirmed the diagnosis of pure seminoma extending through the tunica albuginea (fig. 1, B). The main left nodule comprised testicular and ovarian tissues (fig. 2, B and C). No evidence of metastasis was found. The patient received 3 cycles of bleomycin, etoposide and cisplatin with no evidence of disease at 24-month followup. Subsequent cytogenetic evaluation of peripheral leukocytes revealed a normal sex chromatin complement 46,XX. No Y chromosome related material in frozen sections of the tumor was found on fluorescent in situ hybridization using a probe that hybridizes to highly repeat tandem monomers at the centromere regions of the human Y chromosome. Polymerase chain reaction amplification of the tumor and peripheral leukocyte DNA with primer specific for the sex determining region of the Y chromosome were negative.