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Purpose: We determined the role of purine and pyrimidine nucleotides in erectile function in diabetic rats., Materials and Methods: A total of 60 adult male rats were divided into 2 groups, including 30 controls and 30 treated with streptozotocin (60 mg/kg) for 8 weeks to induce hyperglycemia. Changes in intracavernous pressure after intracrural injections of adenosine 5'triphosphate and adenosine 5'triphosphate analogues in control and diabetic rats, and the relaxant response to electrical field stimulation of precontracted corpus cavernosum smooth muscle in organ baths were investigated. The localization of P2X1, P2Y1 and P2Y2 receptors was assessed in penile tissue via an immunohistochemical approach., Results: Corpus cavernosum smooth muscle relaxation in vivo and by electrical field stimulation in vitro was significantly decreased in diabetic rats. Adenosine 5'triphosphate (P2X, P2Y), 2-methylthioadenosine 5'triphosphate (P2Y1) and uridine 5'-triphosphate (P2Y2) agonists but not alpha,beta-methylene adenosine 5'triphosphate (a P2X1 agonist) significantly improved the erectile response to electrical field stimulation in diabetic rat corpus cavernosum smooth muscle. Although intracavernous pressure/mean arterial pressure values in the rats were not restored in the presence of the P2X1 antagonist PPADS, the relaxation response to electrical field stimulation in isolated corpus cavernosum smooth muscle from diabetic rats was improved. Abundant immunoreactivity for PX1 and P2Y2 receptors was observed in penile tissues from diabetic rats compared to that from control rats., Conclusions: These results demonstrate 1) heterogeneous effects of purinergic agonists on corporeal function in diabetic rats, and 2) the activation of P2Y1 and P2Y2 receptor relaxation of corpus cavernosum smooth muscle to induce erection in rats and perhaps improve erectile function in men with diabetes.

Background: Bone morphogenetic proteins (BMPs) exert osteoinductive effects in prostate cancer (PC) via uncharacterized mechanisms. In this study, we investigated whether the nuclear transcription factor NF-kappaB, implicated in PC metastasis, is involved in transcriptional regulation and activation of BMP-2 or BMP-4/Smad signaling in PC cells., Methods: NF-kappaB inhibition was achieved by IkappaBalpha super-repressor adenoviral vector and activation was monitored by EMSA and reporter assays. BMP expression and activation was measured by PCR and reporter assays. Promoter binding assay was performed by chromatin immunoprecipitation (ChIP) assay. Smad1/5/8 phosphorylation was measured by Western blot analysis., Results: PCR and chimeric BMP-2 and BMP-4 luciferase assays demonstrate that NF-kappaB confers robust and selective activation of BMP-2 in p65 overexpressing or rhTNF-alpha-stimulated PC cells. Inhibition of NF-kappaB significantly reduced transcript levels and autocrine production of BMP-2 by rhTNF-alpha stimulated C4-2B cells and to a lesser extent by the parental LNCaP cells. Selective inhibition of PI3K/Akt suppressed the NF-kappaB-induced BMP-2 promoter activity. Furthermore, suppression of NF-kappaB activation decreased the transcript levels and BMP-2-induced phosphorylation of Smad1/5/8, critical downstream targets of BMP-2 signaling in PC cells. Notably, the activation of BMPRII by BMP-2 is required for modulation of Smad activation by NF-kappaB in PC cells. Based on ChIP analysis, the transcriptional regulation of BMP-2 gene by NF-kappaB may be partially attributed to binding to kappab site on the BMP-2 promoter., Conclusions: The data suggest that PI3K/Akt-NF-kappaB axis may promote PC bone metastasis in part by regulating transcription and activation of the BMP-2-Smad signaling cascade in osteotropic PC cells.

The chemokine stromal-derived factor-1alpha (SDF-1alpha/CXCL-12) and its receptor, CXCR4, play a crucial role in adhesion and transendothelium migration (TEM) of prostate cancer cells. We tested the hypothesis that enhanced expression of CXCR4 in prostate cancer cells is dependent upon SDF-1alpha-mediated activation of nuclear factor-kappaB (NF-kappaB). SDF-1alpha increased the CXCR4 mRNA and protein expression in PC-3 cells but not in LNCaP cells. Similarly, SDF-1alpha enhanced the NF-kappaB-dependent transcriptional activity in PC-3 cells but not in LNCaP cells. SDF-1alpha increased PC-3 cell adhesion to the human umbilical vein endothelial cell monolayer and enhanced TEM, which was abrogated with anti-CXCR4 monoclonal antibody (mAb). Suppression of NF-kappaB activity in PC-3 cells by a mutant IkappaBalpha super-repressor adenoviral vector decreased the CXCR4 mRNA expression and inhibited adhesion and TEM. Transient overexpression of p65 subunit of NF-kappaB in PC-3 cells up-regulated CXCR4 receptor expression and increased the adhesion and TEM of these cells in response to SDF-1alpha gradient. Treatment of PC-3 cells with SDF-1alpha leads to nuclear translocation of NF-kappaB protein within 15 to 30 minutes, which correlated with IkappaBalpha phosphorylation. A p42/44 mitogen-activated protein kinase [MAPK, extracellular signal regulated kinase-1/2 (ERK-1/2)] biphasic activation pattern was observed in these cells at 15 minutes and 3 hours after SDF-1alpha treatment. Phosphorylation of IkappaB kinase alpha was observed within 30 minutes, which was blocked by PD98059 [MAPK kinase (MEK) inhibitor]. PD98059 cotreatment significantly inhibited SDF-1alpha-induced NF-kappaB reporter activity and CXCR4 receptor expression as shown by flow cytometry. These data suggest that SDF-1alpha-induced expression of CXCR4 in PC-3 cells is dependent on MEK/ERK signaling cascade and NF-kappaB activation.

Our previous report of predominant activation of nuclear transcription factor NF-kappaB in the bladder urothelium of interstitial cystitis (IC) patients suggests a potential role for this nuclear factor in the pathogenesis of the disease. Although NF-kappaB has been implicated in the pathogenesis of several inflammatory diseases, the downstream mechanism(s) by which it can mediate its effects are still fragmentary. In this study, we examined the role of this nuclear factor on the induction of proinflammatory cytokine gene expression in human bladder carcinoma T24 cells and further examined their corresponding protein levels in the urine of IC patients. T24 cells transduced with a dominant-negative super-repressor IkappaB mutant (pAxCAmIkappaB-M) or wild-type adenoviral vectors in the presence or absence of rhTNF-alpha. Transduction efficiency and ability of pAxCAmIkappaB-M to inhibit NF-kappaB activation were monitored by in situ reporter beta-galactosidase and gel mobility shift assays, respectively. Expression profile analysis of proinflammatory cytokines was measured in cells and urine of IC patients using RT-PCR and ELISA, respectively. The activation of NF-kappaB by rhTNF-alpha was associated with 27, eight, ten and sevenfold increases in the TNF-alpha, IL-1beta, IL-6 and IL-8 transcripts, respectively. In contrast, abrogation of the TNF-alpha-induced cytokine gene expression by an adenovirus super-repressor IkappaB mutant vector demonstrate that these effects were NF-kappaB-dependent. Interestingly, the NF-kappaB-induced expression of these transcripts correlates with increased protein levels of NF-kappaB-regulated proinflammatory factors in the urine of IC patients in comparison to controls. That these factors are capable of activating NF-kappaB in urothelial cells suggests a pivotal role for this nuclear transcription factor in the pathophysiology of the disease, possibly by inducing aberrant immune and inflammatory responses within the bladder of IC patients.

Acquirement of multi-drug resistance by tumor cells represents a major obstacle in the management of prostate cancer. Such resistance was demonstrated in the androgen-independent DU-145 cells in response to paclitaxel and the mechanisms by which these cell develops resistance was not understood. The objective of this study was to examine whether abrogation of the constitutively active NF-kappaB in the chemoresistant, androgen independent DU-145 prostate cancer cells will enhance their sensitivity to cytototoxic agents. Inhibition of NF-kappaB by a dominant negative super-repressor IkappaB mutant adenoviral construct enhanced the apoptotic potentials of paclitaxel and rhTNF-alpha in these cells. Using reporter assays and RT-PCR analysis, we demonstrate that paclitaxel-induced cell death was associated with an increase in NF-kappaB activation and MDR-1 gene expression. Abrogation of these effects by the dominant negative IkappaB adenoviral construct suggests that induction and/or constitutive activation of NF-kappaB can block the paclitaxel-induced apoptotic signaling pathways in this cell line, possibly by increasing the expression of anti-apoptotic and MDR-1 gene products, leading to development of chemoresistance in these cells. We conclude that inhibition of NF-kappaB activation may have therapeutic implications for prostate cancer.

Purpose: We determined whether adenoviral gene transfer of endothelial nitric oxide synthase (eNOS) to the penis of streptozotocin induced diabetic rats could improve the impaired erectile response., Materials and Methods: Two experimental groups of animals were transfected with adenoviruses, including streptozotocin (Sigma Chemical Company, St. Louis, Missouri) diabetic rats with AdCMVbetagal and streptozotocin diabetic rats with AdCMVeNOS. At 1 to 2 days after transfection these study animals underwent cavernous nerve stimulation to assess erectile function and their responses were compared with those of age matched control rats. In control and transfected streptozotocin diabetic rats eNOS and neuronal NOS (nNOS) were examined by Western blot analysis. Constitutive and inducible NOS activities were evaluated in the presence and absence of calcium by L-arginine to L-citrulline conversion and nitrate plus nitrite levels were measured. In control and streptozotocin diabetic penes beta-galactosidase activity and localization were determined., Results: After transfection with AdCMVbetagal beta-galactosidase was localized to the endothelium and smooth muscle cells of the streptozotocin diabetic rat penis. Streptozotocin diabetic rats had a significant decrease in erectile function, as determined by peak and total intracavernous pressure (area under the curve) after cavernous nerve stimulation compared with control rats. Streptozotocin diabetic rats transfected with AdCMVeNOS had peak intracavernous pressure and area under the curve similar to those in control animals. This change in erectile function was a result of eNOS over expression with an increase in eNOS protein expression and constitutive NOS activity as well as an increase in nitric oxide biosynthesis, as reflected by an increase in cavernous nitrate plus nitrite formation. There was no change in nNOS protein expression or calcium independent conversion of NOS (inducible NOS activity)., Conclusions: Adenoviral gene transfer of eNOS significantly increased peak and total intracavernous pressure to cavernous nerve stimulation in streptozotocin diabetic rats to a value similar to the response observed in control rats. Our results suggest that eNOS contributes significantly to the physiology of penile erection. These data demonstrate that in vivo adenoviral gene transfer of eNOS can physiologically improve erectile function in the streptozotocin diabetic rat.

Increased superoxide anion (O(2)(-).) may contribute to vascular dysfunction in aging. In aged cavernosal tissue, lucigenin-enhanced chemiluminescence demonstrated a threefold increase in superoxide formation, and the oxidative fluorescent probe hydroethidine indicated higher superoxide levels throughout the aged penis. This increase in superoxide was associated with impaired cavernosal nerve-mediated and agonist-induced erectile responses, increased nitrotyrosine staining, and lower cGMP levels, but no compensatory change in cavernosal extracellular (EC)-superoxide dismutase (EC-SOD) mRNA or protein. In vivo adenoviral (Ad) gene transfer of EC-SOD to the penis resulted in higher expression of EC-SOD mRNA, protein, SOD activity, cGMP levels, and lower nitrotyrosine staining. Transfection with AdCMVEC-SOD resulted in a significant increase in erectile response to cavernosal nerve stimulation, ACh, and zaprinast to a magnitude similar to young rats. These data provide evidence in support of the hypothesis that erectile dysfunction associated with aging is related in part to an increase in cavernosal O(2)(-). formation. Gene-transfer of EC-SOD reduces superoxide formation and restores age-associated erectile function and may represent a novel therapeutic target for the treatment of erectile dysfunction.

Background and Purpose: In an effort to better understand the pathophysiology of ureteropelvic junction (UPJ) obstruction and to determine possible predisposing factors for endopyelotomy failures, we compared the activation of the nuclear factor NF-kappa B and proinflammatory cytokines in patients who failed endopyelotomy and post-primary pyeloplasty patients. We hypothesized that an imbalance toward proinflammatory cytokines may promote fibrosis prior to and after endopyelotomy in patients with severe hydronephrosis., Patients and Methods: The charts of patients who underwent open pyeloplasty at our institution were reviewed. Group I was the control group, consisting of 10 patients who had undergone radical nephrectomy for renal-cell carcinoma without involvement of the renal pelvis. Group II was the endopyelotomy failure group and included 11 patients over the age of 15 years treated for symptomatic UPJ obstruction. Group III included six patients who underwent primary pyeloplasty. Paraffin-embedded blocks of UPJ segments from each of these patients were obtained, and immunohistochemical detection of NF-kappa B activation, interleukin (IL)-6, and hypoxia-inducing factor (HIF) was performed. As an in-vitro model, activation of NF-kappa B and cytokine gene expression were also monitored in human bladder T24 urothelial cells 24 hours after exposure to hypoxia (1% O(2)) in the presence and absence of NF-kappa B inhibitor. The activation of NF-kappa B was determined by immunocytochemical analysis, whereas cytokine gene expression was measured using reverse transcriptase-polymerase chain reaction., Results: Immunoreactivity to NF-kappa B was observed in the nuclei of the urothelium and muscle layer in all patients in group II. Such immunostaining suggests increased nuclear translocation and activation of this transcription factor. Those patients with increased expression of NF-kappa B demonstrated increases in IL-6 expression as well. Hypoxia-inducing factor was identified in all the tissue samples tested in group II. Stimulation of the human urothelial cells by hypoxia, known to activate NF-kappa B, resulted in an increase in the levels of IL-1 and IL-6 transcripts compared with hypoxia-exposed cells in the presence of NF-kappa B inhibitors., Conclusions: The NF-kappa B factor was upregulated and proinflammatory cytokines were activated in patients with UPJ obstruction who failed endopyelotomy. Proinflammatory cytokines upregulated by this nuclear factor can result in fibrosis and affect healing after endopyelotomy. Hypoxia appears to activate this nuclear factor. Further studies correlating the degree of hydronephrosis with the activation of HIF are necessary to clarify the role of severe hydronephrosis and its management in UPJ obstruction.

We describe the effects of tumor necrosis factor alpha-related apoptosis inducing ligand (TRAIL) on the induction of apoptosis in two related prostate cancer cell lines, PC3AR and PC3Neo. TRAIL is a potent drug, which induces apoptosis preferentially in cancer cells. Treatment of prostate cancer cells, reduced survival by approximately 41% in PC3AR, but only approximately 18% PC3Neo were killed. Western analysis demonstrated that increased apoptotic response of PC3AR cells may be due to differential response of death receptors DR4, DR5 and decoy receptors DcR1 and DcR2. Caspases-8, -9, -3 and Bid were highly activated in PC3AR cells compared to PC3Neo. Furthermore, lower apoptotic response of PC3Neo was probably due to higher expression of NFkappaB. Blocking the function of NFkappaB by adenoviral infection of mutated IkappaB, increased apoptotic response confirming the influence of NFkappaB. Thus, we have demonstrated the role of NFkappaB in the differential response of prostate cancer cells to TRAIL.