Hari K. Koul

Oxidative stress is inherent in prostate cancer cells and is required for aggressive phenotype

Reactive oxygen species (ROS) and the coupled oxidative stress have been associated with tumor formation. Several studies suggested that ROS can act as secondary messengers and control various signaling cascades. In the present studies, we characterized the oxidative stress status in three different prostate cancer cells (PC3, DU145, and LNCaP) exhibiting various degree of aggressiveness and normal prostate cells in culture (WPMY1, RWPE1, and primary cultures of normal epithelial cells). We observed increased ROS generation in cancer cells compared with normal cells, and that extramitochondrial source of ROS generator, NAD(P)H oxidase (Nox) systems, are associated with the ROS generation and are critical for the malignant phenotype of prostate cancer cells. Moreover, diphenyliodonium, a specific Nox inhibitor, blocked proliferation, modulated the activity of growth signaling cascades extracellular signal-regulated kinase (ERK)1/ERK2 and p38 mitogen-activated protein kinase as well as AKT protein kinase B, and caused cyclin B-dependent G(2)-M cell cycle arrest. We also observed higher degrees of ROS generation in the PC3 cells than DU145 and LNCaP, and that ROS generation is critical for migratory/invasiveness phenotypes. Furthermore, blocking of the ROS production rather than ROS neutralization resulted in decreased matrix metalloproteinase 9 activity as well as loss of mitochondrial potential, plausible reasons for decreased cell invasion and increased cell death. Taken together, these studies show, for the first time, the essential role of ROS production by extramitochondrial source in prostate cancer and suggest that therapies aimed at reducing ROS production might offer effective means of combating prostate cancer in particular, and perhaps other malignancies in general.

Oxidative stress in prostate cancer.

As prostate cancer and aberrant changes in reactive oxygen species (ROS) become more common with aging, ROS signaling may play an important role in the development and progression of this malignancy. Increased ROS, otherwise known as oxidative stress, is a result of either increased ROS generation or a loss of antioxidant defense mechanisms. Oxidative stress is associated with several pathological conditions including inflammation and infection. ROS are products of normal cellular metabolism and play vital roles in stimulation of signaling pathways in response to changing intra- and extracellular environmental conditions. Chronic increases in ROS over time are known to induce somatic mutations and neoplastic transformation. In this review we summarize the causes for increased ROS generation and its potential role in etiology and progression of prostate cancer.

The Role of 3-Dimensional Mapping Biopsy in Decision Making for Treatment of Apparent Early Stage Prostate Cancer

PURPOSEnWe determined the impact of a grid based, transperineal 3-dimensional mapping biopsy on decision making for primary management of early stage prostate cancer.nnnMATERIALS AND METHODSnWe prospectively performed 3-dimensional mapping biopsy on 180 consecutive men who presented to our clinic between 2006 and 2009 with early stage, organ confined prostate cancer based on transrectal ultrasound guided 10 to 12-core biopsy, and on 35 with prior negative transrectal ultrasound biopsies.nnnRESULTSnAt presentation median patient age was 60.5 years (range 43 to 77), median prostate specific antigen was 4.8 ng/ml (range 0.5 to 72.4) and median prostate volume was 35 cc (range 9 to 95). The median number of cores acquired by transrectal ultrasound and 3-dimensional mapping biopsy was 12 and 56, and the median number of positive cores was 1 and 2, respectively. We documented Gleason score upgrade in 49 of 180 cases (27.2%) and up-stage in 82 (45.6%). The incidence of urinary retention catheter requirement of greater than 48 hours was 3.2% and the incidence of transient orthostatic hypotension was 5%. No urinary tract infections were documented. A total of 38 men received radical extirpative therapy, 11 radiation and 45 cryotherapy while 60 enrolled in a targeted focal therapy study, 44 entered active surveillance and 5 underwent other focal investigational treatments. Post-mapping data on 12 men were not available for analysis.nnnCONCLUSIONSnThree-dimensional mapping biopsy revealed that a significant portion of men initially diagnosed with apparently low risk disease harbored clinically significant cancers requiring more aggressive therapy. The technique also enabled a number of men with low risk disease to elect surveillance or another less morbid option.

Mitogen Activated Protein kinase signal transduction pathways in the prostate

The biochemistry of the mitogen activated protein kinases ERK, JNK, and p38 have been studied in prostate physiology in an attempt to elucidate novel mechanisms and pathways for the treatment of prostatic disease. We reviewed articles examining mitogen-activated protein kinases using prostate tissue or cell lines. As with other tissue types, these signaling modules are links/transmitters for important pathways in prostate cells that can result in cellular survival or apoptosis. While the activation of the ERK pathway appears to primarily result in survival, the roles of JNK and p38 are less clear. Manipulation of these pathways could have important implications for the treatment of prostate cancer and benign prostatic hypertrophy.

Loss of PDEF, a prostate-derived Ets factor is associated with aggressive phenotype of prostate cancer: Regulation of MMP 9 by PDEF

BackgroundProstate-derived Ets factor (PDEF) is expressed in tissues of high epithelial content including prostate, although its precise function has not been fully established. Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer.ResultsWe observed decreased PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immuno-histochemical methods. Reintroduction of PDEF profoundly affected cell behavior leading to less invasive phenotypes in three dimensional cultures. In addition, PDEF expressing cells had altered cell morphology, decreased FAK phosphorylation and decreased colony formation, cell migration, and cellular invasiveness. In contrast PDEF knockdown resulted in increased migration and invasion as well as clonogenic activity. Our results also demonstrated that PDEF downregulated MMP9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate decreased PDEF expression and increased MMP9 expression during the transition to aggressive prostate cancer.ConclusionsThese studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, and that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP9 expression in clinical samples of prostate cancer. Based on these exciting results, we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer.

Vascular endothelial growth factor (VEGF) gene therapy using a nonviral gene delivery system improves erectile function in a diabetic rat model

Erectile dysfunction (ED) is a cause of decreased quality of life in more than 70% of diabetic men. Vascular endothelial growth factor (VEGF) has shown to improve overall endothelial and smooth muscle cell dysfunction in models of ED. We describe a novel technique for nonviral, in vivo gene transfection of VEGF in the rat corpus cavernosum. Diabetic rats were transfected with DNA encoding a fusion VEGF/green fluorescent protein (GFP) complex and fluorescence microscopy was used to monitor the expression of VEGF–GFP fusion protein. Western blot and PCR analyses confirmed the expression of the GFP–VEGF fusion protein and mRNA. Functional studies using cavernous nerve stimulation revealed maximal intracavernous pressures (ICPs) of 63.1u2009mmu2009Hg, and 30.7u2009mmu2009Hg in the normal and diabetic control groups, respectively, and 47.4u2009mmu2009Hg in VEGF–GFP-transfected diabetic group. Immunohistochemical analysis of the cavernosal tissue from transfected rats showed increased smooth muscle content compared with the diabetic control group. We show for the first time in our animal model that expression of the transfected VEGF in cavernosal tissue leads to an overall improvement of maximal ICP and smooth muscle content. On the basis of these results, it is tempting to speculate that our nonviral vector system offers an excellent system for gene delivery into cavernosal tissue, and that VEGF gene therapy using this system could be useful in improving erectile function in diabetic men.

Correlation between LUTS (AUA-SS) and erectile dysfunction (SHIM) in an age-matched racially diverse male population: data from the Prostate Cancer Awareness Week (PCAW)

The relationship between lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia and sexual health in men participating in a national multicenter screening program was studied. A total of 12u2009679 men were screened for prostate cancer in the year 2003. Of these, 6641 men had completed both the American Urological Association Symptom Score (AUA-SS) and the Sexual Health Inventory for Men (SHIM) questionnaires. We assessed the apparent effect of comorbidities (ischemic heart disease, hypertension, hypercholesteremia and diabetes), smoking habits and testosterone level on the overall sexual health. Age and race were also assessed as factors affecting the SHIM score. We used a general linear multivariable regression analysis to express the effect of these variables on the sexual health in these men adjusting for the apparent effect of LUTS. The mean and median age of the population was 58.4 ± 9.8 and 58u2009y, respectively. The median AUA-SS was 4/25 (mean=5.7 ± 5.3) and SHIM score was 19/25 (mean=16.3 ± 5.9). Of the men, 4948 (75%) were Caucasian and 1154 (17%) were from African-American racial origin. A high AUA-SS appears to have a negative effect on the overall sexual health (P<0.05) after adjusting for all other confounding factors. As expected, age showed a significant inverse correlation with SHIM score (P<0.05). Caucasian men on average appear to have a significantly higher SHIM score by 6.5 points when compared to African-American men after adjusting for age, comorbidities, smoking habits, and AUA-SS (P<0.05). However, with increasing age, the difference in SHIM score diminishes between the two groups. Further, smoking and comorbidities were strong predictors of poor sexual health performance. Interestingly, hypogonadism (testosterone <300u2009ng/dl) was not a significant risk factor (P=0.104) when adjusting for all other variables. Nonetheless, in a univariate analysis, testosterone levels significantly correlated with reported SHIM scores (P<0.05). The overall sexual health in aging men is substantially affected not only by age, but by the severity of their urinary symptoms after adjusting for the most common known risk factors, suggesting perhaps a common underlying pathophysiology. Moreover, race appears to constitute another neglected potential risk factor, which should be investigated further in future studies.

Role of Testosterone in Managing Advanced Prostate Cancer

Androgen deprivation therapy is frequently used to treat patients with advanced prostate cancer. New therapies for metastatic castration-resistant prostate cancer have drawn increased attention to serum and intratumoral testosterone levels. The present review examines the role of testosterone in prostate cancer progression, discusses the nuances and potential pitfalls in measuring serum testosterone using available assays, and summarizes current data relevant to the arguments for and against achieving and maintaining the lowest possible testosterone levels during androgen deprivation therapy, including the adverse effects of such treatment. Incorporating this information, we have made recommendations incorporating testosterone evaluation and its effect on the clinical decision-making process.

Partial Bladder Outlet Obstruction in Mice May Cause E-Cadherin Repression through Hypoxia Induced Pathway

PURPOSEnPosterior urethral valves are the most common cause of partial bladderxa0outlet obstruction in the pediatric population. Posterior urethral valves is a devastating clinical problem that ultimately results in urinary incontinence, neurogenic bladder and renal impairment. Despite improvements in medical and surgical management at least a third of patients with this condition progress toxa0end stage renal disease and half will have problems with urinary incontinence. To achieve better understanding of the mechanism associated with clinical events we generated partial bladder outlet obstruction in male mice. In this model we investigated pathological consequences and underlying molecular mechanisms secondary to partial bladder outlet obstruction.nnnMATERIALS AND METHODSnFive to 8-week-old male C57BL/6 mice were divided intoxa0a surgical obstruction group and a sham operated group that served as controls. Bladders and kidneys were harvested from each group 1, 2, 3, 5 and 7xa0days postoperatively, respectively. We examined histological and biochemical alterations, and further investigated our hypothesis that partial bladder outlet obstruction induces hypoxia activated profibrotic signaling and changes in gene expression in the bladder.nnnRESULTSnMice with partial bladder outlet obstruction demonstrated significant increases in bladder mass and urinary retention compared to sham operated mice.xa0Obstruction caused fibrosis in the bladder and induced up-regulation of profibrotic genes, hypoxia-inducible factors and epithelial-mesenchymal transition-inducing transcription factors, resulting in E-cadherin down-regulation.nnnCONCLUSIONSnObstruction induced significant histological and molecular alterations, including activation of the hypoxia-inducible factors pathway in the mouse bladder. Activation of epithelial-mesenchymal transition-inducing transcription factors by hypoxia-inducible factors might have an important role in thexa0pathogenesis of partial bladder outlet obstruction.

Differential effects of valproic acid on growth, proliferation and metastasis in HTB5 and HTB9 bladder cancer cell lines

High grade invasive bladder cancer is a leading cause of cancer deaths and treatment options are limited for this type of cancer. Recent studies have reported anticancer effects of valproic acid in many cancers and also in superficial bladder cancer. Acute valproic acid administration suppressed cell proliferation in a time- and dose-dependent manner in two muscle-invasive human bladder cancer cell lines (HTB5 and HTB9), with accompanying G1 phase cell cycle arrest. A significant decrease in colony formation ability and invasiveness was seen with valproic acid treatment though the effectiveness varied with cell type. Our results suggest a role for valproic acid in inhibiting growth and invasion of muscle-invasive bladder cancer.