Abstract 9: Oxidative stress and antioxidant status in high-risk prostate cancer subjects

Prostate cancer is the most commonly diagnosed cancer among men in the United States. Epidemiological, experimental and clinical studies have implicated chronic inflammation and oxidative stress in the development and progression of prostate cancer. Diet, environmental carcinogens, aging, and other inflammatory diseases cause aberration in reactive oxygen species (ROS) which may play critical roles in the development and progression of prostate cancer. Chronic inflammation results in lipid peroxidation and generation of highly reactive products with the potential to damage DNA. The extent of ROS-induced oxidative damage can be determined by measuring reductions in levels of endogenous antioxidant defense enzymes such as glutathione-s-transferase (GST), glutathione peroxidase (GSH-Px), glutathione reductase (GSH-R), catalase (CAT), superoxide dismutase (SOD) and non-protein thiols, which participate in detoxification processes. The aim of this study was to assess the oxidative status and antioxidant defense mechanisms in 20 men, 54-84 years of age, with increased risk of developing prostate cancer because of the presence of high-grade prostatic intraepithelial neoplasia (HGPIN) in their prostate biopsies, as compared to 20 healthy men in the same age range whose prostate biopsies showed no evidence of HGPIN. Total glutathione levels were measured in red blood cells, and plasma levels of GSH-Px, GSH-R, CAT, SOD, and PSA were analyzed. Data obtained after analysis was represented as mean, standard error and box plot. Serum PSA levels were significantly (p<0.0001) higher in men with HGPIN, whereas glutathione (P=0.002) levels were higher in men without HGPIN. Levels of 8-hydroxydeoxyguanosine (8-OHdG), an oxidized nucleoside of DNA that is most often detected in the DNA of white blood cells, were significantly (p<0.00001) increased in men with HGPIN. There was no significant difference in levels of GSH-R, GSH-Px, lipid peroxide products, CAT, and SOD in men with or without HGPIN. A significant association in between CAT and GSH-Px activity [r= -0.33 (P=0.04)]; PSA levels and 8-OHdG [r= 0.57 (P=0.002] and between glutathione and 8-OHdG [r= -0.39 (P=0.038] were noted between men with HGPIN and healthy controls using Pearson correlation coefficient. These findings indicate that oxidative stress induces imbalances in oxidant/antioxidant status. Increased 8-OHdG levels may lead to oxidative damage and may thereby play an important role in the development of prostate cancer.

Citation Format: Sanjeev Shukla, Janmejai K. Srivastava, Rajnee Kanwal, Akbar Nawab, Haripaul Sharma, Natarajan Bhaskaran, Claudia Lillibridge, Lee E. Ponsky, Pingfu Fu, Gregory T. MacLennan, Sanjay Gupta. Oxidative stress and antioxidant status in high-risk prostate cancer subjects. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 9. doi:10.1158/1538-7445.AM2013-9

Pneumodissection: an alternative protective technique for the percutaneous cryoablation of small renal masses

INTRODUCTION

Percutaneous cryoablation is an emerging treatment option for the small renal mass. It poses a risk of thermal injury to adjacent tissues, limiting its application. We describe pneumodissection, a novel technique for preventing thermal injury during percutaneous cryoablation.

MATERIALS AND METHODS

The cases of 4 patients who underwent percutaneous renal cryoablation and pneumodissection were retrospectively reviewed.

RESULTS

Pneumodissection mechanically separated four tumors from overlying bowel segments (mean distance 1.2 ± 0.4 cm), permitting successful cryoablation. There were no complications or recurrences with 7.5 months of follow-up.

CONCLUSIONS

Pneumodissection is a feasible displacement technique that facilitates percutaneous cryoablation in at-risk patients. Further study is warranted.

Protection against oxidative DNA damage and stress in human prostate by glutathione S-transferase P1

The pi-class glutathione S-transferase (GSTP1) actively protect cells from carcinogens and electrophilic compounds. Loss of GSTP1 expression via promoter hypermethylation is the most common epigenetic alteration observed in human prostate cancer. Silencing of GSTP1 can increase generation of reactive oxygen species (ROS) and DNA damage in cells. In this study we investigated whether loss of GSTP1 contributes to increased DNA damage that may predispose men to a higher risk of prostate cancer. We found significantly elevated (103%; P < 0.0001) levels of 8-oxo-2'-deoxogunosine (8-OHdG), an oxidative DNA damage marker, in adenocarcinomas, compared to benign counterparts, which positively correlated (r = 0.2) with loss of GSTP1 activity (34%; P < 0.0001). Silencing of GSTP1 using siRNA approach in normal human prostate epithelial RWPE1 cells caused increased intracellular production of ROS and higher susceptibility of cells to H2 O2 -mediated oxidative stress. Additionally, human prostate carcinoma LNCaP cells, which contain a silenced GSTP1 gene, were genetically modified to constitutively express high levels of GSTP1. Induction of GSTP1 activity lowered endogenous ROS levels in LNCaP-pLPCX-GSTP1 cells, and when exposed to H2 O2 , these cells exhibited significantly reduced production of ROS and 8-OHdG levels, compared to vector control LNCaP-pLPCX cells. Furthermore, exposure of LNCaP cells to green tea polyphenols caused reexpression of GSTP1, which protected the cells from H2 O2 -mediated DNA damage through decreased ROS production compared to nonexposed cells. These results suggest that loss of GSTP1 expression in human prostate cells, a process that increases their susceptibility to oxidative stress-induced DNA damage, may be an important target for primary prevention of prostate cancer.

Endoscopic snare resection of bladder tumors: evaluation of an alternative technique for bladder tumor resection

Transurethral resection of bladder tumor (TURBT) is the standard of care for initial bladder tumor management. In response to its shortcomings, we propose an alternative technique for tumor resection and retrieval: The endoscopic snare resection of bladder tumor (ESRBT). Eleven tumors managed by ESRBT were reviewed retrospectively. Via cystoscopy, tumors were resected en bloc with an electrosurgical polypectomy snare and retrieved transurethrally. Safety and efficacy were assessed by clinical and pathologic outcomes. ESRBT was highly effective for appropriate tumors. Tumor size and location varied: Two small, six medium, three large; six lateral wall, two dome, two trigone, one posterior wall. Half of initial urothelial carcinoma specimens contained muscle. There were no intraoperative or postoperative complications (mean follow-up: 17 mos; range 10-25 mos). ESRBT is a feasible technique for the resection of pedunculated bladder tumors. It offers evident and theoretical advantages over TURBT and may augment bladder tumor management. Further study is needed.

Abstract 2569: Lyc-O-Mato causes cell cycle arrest and apoptosis in human bladder transitional carcinoma cells

Approximately two thirds of new bladder cancer cases in the United States are superficial papillary transitional cell carcinoma (TCC), the majority of which are low-grade neoplasms. Data suggest that bladder carcinogenesis is a multi-step, multi-focal (field effect) process, possibly involving the spread of pre-malignant clones-all of which are prerequisites for effective preventive and/or interventional approaches. Epidemiological data suggests an inverse relationship between serum levels of carotenoids and risk of bladder cancer which has encouraged further investigation. In this study, we evaluated the effect of Lyc-O-Mato® (a crude tomato extract containing 10% lycopene and other tomato phytonutrients viz. tocopherols, phytoene, phytofluene, beta-carotene, phospholipids and phytosterols) on human bladder cancer cell growth, cell cycle modulation, induction of apoptosis, and associated molecular alterations. Treatment of bladder cancer cell lines (T-24, high-grade TCC and TCC-SUP, high-grade invasive tumor) with Lyc-O-Mato® at doses of 1-60µM resulted in inhibition of cell growth along with a G1 arrest in T24 cells and G2/M arrest in TCCSUP cells at 24 h post-treatment. In other studies, Lyc-O-Mato® treatment strongly induced the expression of p21/waf1 and p27/kip1, and resulted in a decrease in cyclin-dependent kinases (CDKs) and cyclins involved in G1 and G2/M progression in T24 and TCC SUP cells. Lyc-O-Mato® exposure to these cells showed an increased interaction between cyclin dependent kinase inhibitors (CDKIs)-cyclin-dependent kinases (CDKs) and decrease in the interaction of cyclins and CDKs with their respective stages of the cell cycle. Furthermore, Lyc-O-Mato® treatment significantly reduced the phosphorylation of Retinoblastoma at Serine780, although no significant changes were observed in the total levels of this protein. In additional studies, Lyc-O-Mato® showed a dose- and time-dependent apoptotic death in both T24 and TCC SUP cells which was associated with significant downregulation of survivin along with the enhancement of pro-apoptotic protein, Bax. These observations provide a strong rationale for further evaluating preventive and/or intervention strategies for Lyc-O-Mato® in pre-clinical models of bladder cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2569. doi:1538-7445.AM2012-2569

Contrast-induced nephropathy and nephrogenic systemic fibrosis: minimizing the risk

INTRODUCTION

Contrast-enhanced cross-sectional imaging is essential to the urologist's practice. Traditionally, patients with impaired renal function could not be imaged with a computed tomography (CT) scan with contrast due to the risk of contrast-induced nephropathy (CIN). These patients could alternatively be imaged by magnetic resonance imaging (MRI) with gadolinium. However, the recent identification of the association between nephrogenic systemic fibrosis (NSF) and gadolinium administration has created significant challenges for urologists and radiologists when faced with the need for evaluation with contrast-enhanced cross-sectional imaging. In this review, we summarize the most comprehensive articles discussing both NSF and CIN and present a straightforward, evidence-based algorithm to determine the appropriate approach to cross-sectional imaging for all patients, as well as future directions regarding cross-sectional imaging.

MATERIALS AND METHODS

A MEDLINE literature search for review articles from 1966 to August 2009 was performed. Selected additional articles for specific topics were also reviewed. This search yielded a total of 25 articles for NSF and 28 for CIN that were reviewed.

RESULTS

The pathophysiology and risk factors of NSF and CIN are discussed, as well as potential interventions to decrease either morbidity or incidence. A multidisciplinary (urologist, nephrologist, radiologist) evidence-based algorithm is introduced for managing patients in need of cross-sectional imaging.

CONCLUSIONS

The associated risks of contrast-enhanced, cross-sectional imaging has created significant challenges for urologic evaluation. We propose an evidence-based approach to guide patient therapy, which can minimize patient risk and physician anxiety, while simplifying the decision-making process.

Molecular imaging of nuclear factor-κB in bladder as a primary regulator of inflammatory response

PURPOSE

Nuclear factor-κB activation is implicated in chronic inflammatory disorders and it is a key regulator of genes involved in the response to infection, inflammation and stress. Interstitial cystitis and painful bladder syndrome are common inflammatory disorders of the bladder characterized by frequent urination and bladder pain. The role of nuclear factor-κB activation in bladder inflammation is not well defined.

MATERIALS AND METHODS

Female transgenic nuclear factor-κB-luciferase Tag mice (The Jackson Laboratory, Bar Harbor, Maine) were used to perform serial, noninvasive in vivo and ex vivo molecular imaging of nuclear factor-κB activation in the whole body after administering arsenic trioxide (5 mg/kg), lipopolysaccharide (2 mg/kg) or cyclophosphamide (Sigma®) (200 mg/kg) to initiate acute transient bladder inflammation. Pretreatment with dexamethasone (Sigma) (10 mg/kg) was used to modulate cyclophosphamide induced nuclear factor-κB dependent luminescence in vivo.

RESULTS

Treatment of nuclear factor-κB-luciferase Tag mice with chemicals increased luminescence in a time and organ specific manner in vivo and ex vivo. The highest levels of bladder nuclear factor-κB dependent luminescence were observed 4 hours after cyclophosphamide administration. Pretreatment with dexamethasone 1 hour before cyclophosphamide injection significantly down-regulated cyclophosphamide induced bladder nuclear factor-κB dependent luminescence, ameliorated the grossly evident pathological features of acute inflammation and decreased cellular immunostaining for nuclear factor-κB in the bladder.

CONCLUSIONS

Nuclear factor-κB activity may have an important role in the pathophysiology of bladder inflammation. Nuclear factor-κB-luciferase mice can serve as a useful model in which to screen potential candidate drugs for cystitis associated with aberrant nuclear factor-κB activity. Such screening may significantly aid the development of therapeutic strategies to manage inflammatory bladder disorders.

Technical and equipment challenges for laparoendoscopic single-site surgery and natural orifice transluminal endoscopic surgery

Laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES™) are new approaches to minimally invasive surgery. A number of technical challenges need to be overcome and new developments of equipment are required before widespread acceptance of either modality occurs. In this paper we discuss novel approaches and innovations as well as review examples of equipment and platforms that have previously been used for LESS and NOTES. Emphasis is given to urological applications.

Extracorporeal stereotactic radiosurgery for small renal masses

Over the past decade we have witnessed both a grade and stage migration for renal cell carcinoma. This shift in clinicopathology has been met with a paradigm shift in the treatment of these renal mass lesions. This trend has evolved from laparoscopic extirpation to needle-based and now extracorporeal ablation. At the forefront of the extracorporeal, minimally invasive treatment modalities is radiosurgical ablation. Still in its inaugural phase, renal radiosurgery is devoid of any long-term studies; however, short-term studies thus far show enormous potential. Herein we present the current status of radiosurgical ablation of small renal masses.

Prospective evaluation of prostate cancer risk in candidates for inguinal hernia repair

BACKGROUND

Preperitoneal placement of mesh during herniorraphy has been shown to complicate future extirpative prostate surgery. We investigated the value of a prostate cancer screening program in patients considering laparoscopic inguinal herniorrhaphy to identify men at risk of prostate cancer.

STUDY DESIGN

A prospective cohort study was conducted in men 30 years of age or older presenting with inguinal hernia. All patients were counseled on prostate cancer risk and the potential for herniorrhaphy with mesh placement to complicate future pelvic surgery. Serum prostate specific antigen (PSA) values were obtained, and patients determined to be at increased relative risk of prostate cancer were referred for urologic evaluation. Transrectal ultrasonography-guided biopsy was performed if clinically indicated, and operative data for patients undergoing prostate cancer treatment were retrospectively reviewed.

RESULTS

There were 1,324 patients who presented for management of inguinal hernia; 814 of these (median age 60 years) consented to screening. Overall, 259 (32%) had an increased relative risk of prostate cancer based on PSA 1.0 to 2.49 ng/mL, and 152 (19%) had PSA > or = 2.5 ng/mL. Transrectal ultrasonography-guided biopsy was performed in 86 patients. Prostate cancer was identified on initial or repeat biopsy in 31 patients (3.8%), including 1 patient (0.7%) younger than 50 years of age.

CONCLUSIONS

We found the incidence of concurrent prostate cancer with hernia to be low, but 51% of men had PSA values that suggested an increased relative risk of future development of prostate cancer. Men at increased risk of prostate cancer should be made aware of the impact that mesh might have on subsequent treatment options before mesh placement.

Pure natural orifice translumenal endoscopic surgery partial cystectomy: intravesical transurethral and extravesical transgastric techniques in a porcine model

OBJECTIVES

To describe 2 pure natural orifice translumenal endoscopic surgery (NOTES) techniques for partial cystectomy in a porcine model. NOTES is a new minimally invasive modality for performing abdominal surgery without transcutaneous incision.

METHODS

Transurethral-A rigid cystoscope is inserted into the porcine bladder with CO(2) insufflation. With an endoscopic loop device and a grasping device, the targeted area of the bladder is manipulated into the loop. The bladder segment is excised with electrocautery. Transgastric-A gastrotomy is made with a dual channel endoscope in the porcine stomach. The endoscope is inserted and pneumoperitoneum is established by insufflation through a channel. After identifying bladder, 2 endoscopic loops are placed at the intended area of resection. An incision is made between the loops to excise the specimen. In both cases, full-thickness specimen is removed en bloc with the scope and the defect is reapproximated with endoscopic clips.

RESULTS

Transurethral and transgastric NOTES approaches were achieved using standard endoscopic equipment in a porcine model. Transurethral NOTES partial cystectomy was successful in acute (n = 2) and chronic (n = 2) models. The transgastric NOTES approach was successfully performed in an acute animal.

CONCLUSIONS

NOTES partial cystectomy could potentially reduce morbidity of conventional methods of partial cystectomy. Transurethral NOTES may be the least invasive method possible for partial cystectomy. Potential advantages of a transgastric NOTES approach include visualization of adjacent structures, access to sites difficult to reach transurethrally, and lymph node sampling. However, a gastrotomy could be a source of morbidity. Further investigation is required to assess safety, efficacy, and adequate bladder healing.

Natural orifice translumenal endoscopic surgery: myth or reality?

Interest in natural orifice translumenal endoscopic surgery (NOTES) has blossomed since the publication of transgastric peritoneoscopy in animals in 2004. Laboratory research has demonstrated the feasibility of natural orifice surgery and provided insight into the technical innovations necessary to advance the field. Today, natural orifice surgery is entering the clinical realm, both in hybrid laparoscopic-endoscopic cases and a few pure natural orifice procedures. Although the promise of "scarless" surgery entices clinicians and the public alike, care must be taken to introduce novel techniques as safely as possible with critical evaluation of outcomes.