Prostate cancer cells demonstrate unique metabolism and substrate adaptability acutely after androgen deprivation therapy.

BACKGROUND: Androgen deprivation therapy (ADT) has been the standard of care for advanced hormone-sensitive prostate cancer (PC), yet tumors invariably develop resistance resulting in castrate-resistant PC. The acute response of cancer cells to ADT includes apoptosis and cell death, but a large fraction remains arrested but viable. In this study, we focused on intensively characterizing the early metabolic changes that result after ADT to define potential metabolic targets for treatment. METHODS: A combination of mass spectrometry, optical metabolic imaging which noninvasively measures drug responses in cells, oxygen consumption rate, and protein expression analysis was used to characterize and block metabolic pathways over several days in multiple PC cell lines with variable hormone response status including ADT sensitive lines LNCaP and VCaP, and resistant C4-2 and DU145. RESULTS: Mass spectrometry analysis of LNCaP pre- and postexposure to ADT revealed an abundance of glycolytic intermediates after ADT. In LNCaP and VCaP, a reduction in the optical redox ratio [NAD(P)H/FAD], extracellular acidification rate, and a downregulation of key regulatory enzymes for fatty acid and glutamine utilization was acutely observed after ADT. Screening several metabolic inhibitors revealed that blocking fatty acid oxidation and synthesis reversed this stress response in the optical redox ratio seen with ADT alone in LNCaP and VCaP. In contrast, both cell lines demonstrated increased sensitivity to the glycolytic inhibitor 2-Deoxy- d-glucose(2-DG) and maintained sensitivity to electron transport chain inhibitor Malonate after ADT exposure. ADT followed by 2-DG results in synergistic cell death, a result not seen with simultaneous administration. CONCLUSIONS: Hormone-sensitive PC cells displayed altered metabolic profiles early after ADT including an overall depression in energy metabolism, induction of a quiescent/senescent phenotype, and sensitivity to selected metabolic inhibitors. Glycolytic blocking agents (e.g., 2-DG) as a sequential treatment after ADT may be promising.

Epigenetic field alterations in non-tumor prostate tissues detect prostate cancer in urine.

Prostate cancer (PC) development involves epigenetic DNA methylation changes that occur in the tumor. However, distinct DNA methylation changes have been previously found to encompass a widespread cancer field defect involving normal prostate tissue. In the current study, we analyzed a series of DNA methylation field markers to determine if they predict the presence of PC in urine. Urine samples were collected from patients undergoing prostate biopsy with biopsy-proven PC (90), and without PC (77). From the urine pellet, methylated DNA was quantified across several previously identified CpG island regions near the caveolin 1 (CAV1), even-skipped homeobox 1 (EVX1), fibroblast growth factor 1 (FGF1), natural cytotoxicity triggering receptor 2 (NCR2) and phospholipase A and acyltransferase 3 (PLA2G16) genes using bisulfite pyrosequencing. Univariate and multivariate analyses were performed. Urine cell pellets show significant increases in methylation in four of the markers from patients with PC compared to those without PC including EVX1 12.2 vs. 7.7%, CAV1 15.7 vs. 10.36%, FGF1 12.0 vs. 7.1%, and PLA2G16 12.2 vs. 8.3% [all P<0.01]. Area under the ROC Curve (AUCs) were generated for EXV1 (0.74, Odds ratios (OR) 1.09; 95% confidence intervals (CI) 0.94-1.25, CAV1 (0.72, OR 1.18; 95% CI 1.09-1.28) and PLA2G16 (0.76, OR 1.35; 95% CI 1.199-1.51). In combination, a two-marker assay performs better than prostate specific antigen (PSA), AUC 0.77 vs. PSA AUC of 0.6 (P = 0.01) with the lowest error. In addition, FGF1 distinguished between grade group 1 (GG1) and higher grade cancers (P<0.03). In conclusion, applying methylation of field defect loci to urine samples provides a novel approach to distinguish patients with and without cancer.

Synthetic Lethal Metabolic Targeting of Androgen-Deprived Prostate Cancer Cells with Metformin.

The initiation of androgen-deprivation therapy (ADT) induces susceptibilities in prostate cancer cells that make them vulnerable to synergistic treatment and enhanced cell death. Senescence results in cell-cycle arrest, but cells remain viable. In this study, we investigated the mechanisms by which prostate cancer cells undergo senescence in response to ADT, and determined whether an FDA-approved antidiabetic drug metformin has a synergistic effect with ADT in prostate cancer both in vitro and in vivo Our results show that longer term exposure to ADT induced senescence associated with p16INK4a and/or p27kip2 induction. The activation of PI3K/AKT and inactivation of AMPK in senescent cells resulted in mTORC1 activation. In addition, the antiapoptotic protein XIAP expression was increased in response to ADT. The addition of metformin following ADT induced apoptosis, attenuated mTOR activation, reduced senescent cell number in vitro, and inhibited tumor growth in prostate cancer patient-derived xenograft models. This study suggests that combining ADT and metformin may be a feasible therapeutic approach to remove persistent prostate cancer cells after ADT.

Validation of an epigenetic field of susceptibility to detect significant prostate cancer from non-tumor biopsies.

BACKGROUND: An epigenetic field of cancer susceptibility exists for prostate cancer (PC) that gives rise to multifocal disease in the peripheral prostate. In previous work, genome-wide DNA methylation profiling identified altered regions in the normal prostate tissue of men with PC. In the current multicenter study, we examined the predictive strength of a panel of loci to detect cancer presence and grade in patients with negative biopsy tissue. RESULTS: Four centers contributed benign prostate biopsy tissues blocks from 129 subjects that were either tumor associated (TA, Grade Group [GG] ≥ 2, n = 77) or non-tumor associated (NTA, n = 52). Biopsies were analyzed using pyrosequencing for DNA methylation encompassing CpG loci near CAV1, EVX1, FGF1, NCR2, PLA2G16, and SPAG4 and methylation differences were detected within all gene regions (p < 0.05). A multiplex regression model for biomarker performance incorporating a gene combination discriminated TA from NTA tissues (area under the curve [AUC] 0.747, p = 0.004). A multiplex model incorporating all the above genes and clinical information (PSA, age) identified patients with GG ≥ 2 PC (AUC 0.815, p < 0.0001). In patients with cancer, increased variation in gene methylation levels occurs between biopsies across the prostate. CONCLUSIONS: A widespread epigenetic field defect is utilized to detect GG ≥ 2 PC in patients with histologically negative biopsies. These alterations in non-tumor cells display increased heterogeneity of methylation extent and are spatially distant from tumor foci. These findings have the potential to decrease the need for repeated prostate biopsy.

The impact of statins in combination with androgen deprivation therapyin patients with advanced prostate cancer: A large observational study.

BACKGROUND: Statins are thought to possess antineoplastic properties related to their effect on cell proliferation and steroidogenesis. Progression to castrate resistant prostate cancer (CaP) includes de-regulation of androgen synthesis suggesting a role for statins in this setting. Our goal was to assess the role of statin use on oncologic outcomes in patients with advanced CaP being treated with androgen deprivation therapy (ADT). METHODS: The national VA database was used to identify all men diagnosed with CaP who were treated with ADT for at least 6 months between 2000 and 2008 with follow-up through May 2016. Our cohort was stratified based on statin use of at least 6 months duration during the same time. Multivariable Cox proportional hazards analyses with inverse propensity score weighted (IPSW) adjustment were calculated to assess for primary outcomes of CaP-specific survival (CSS), overall survival (OS) and skeletal related events (SREs). RESULTS: A total of 87,346 patients on ADT were included in the study cohort, 53,360 patients used statins and 33,986 did not. Statin users were younger in age (median 73 vs. 76, P < 0.001), more likely to have a higher Charlson comorbidity index (CCI) >3 (3.1% vs. 2.5%, P < 0.001) and more likely to have a high grade (Gleason score 8-10) cancer (12.3% vs. 10.9%, P < 0.001). Statin users had longer OS (median 6.5 vs. 4.0 years P < 0.001) and decreased death from CaP (5-year CSS 94.0% vs. 87.3%, P < 0.001). Statin use was also associated with longer time to a SRE (median 5.9 vs. 3.7 years, P < 0.001). On multivariable Cox proportional hazards analysis with inverse propensity score weighted, statin use was an independent predictor of improved OS (hazard ratio [HR] 0.66, confidence interval [CI] 0.63-0.68; P < 0.001), CSS (HR 0.56, 95% CI 0.53-0.60; P < 0.001), and SREs (HR 0.64, 95%CI 0.59-0.71; P < 0.001) when controlling for age, race, Charlson comorbidity index, prostate-specific antigen, and Gleason score. CONCLUSION: The use of statins in men on ADT for CaP is associated with improved CSS and OS. Statins are inexpensive, well-tolerated medications that offer a promising adjunct to ADT, but require further prospective studies.

Does the Renal Parenchyma Adjacent to the Tumor Contribute to Kidney Function? A Critical Analysis of Glomerular Viability in Partial Nephrectomy Specimens.

OBJECTIVE: To evaluate the viability of glomeruli in the peritumor parenchyma of partial nephrectomy specimens removed for renal cell carcinoma (RCC) and relate it to kidney function, to better understand the contribution of peritumor parenchyma to renal function. MATERIALS AND METHODS: A retrospective analysis of 53 partial nephrectomies containing RCC was performed. Glomeruli within 0.25-cm increments from the tumor were quantified and histologically assessed for viability. Tumor size, minimum and maximum margin size, and pre- and postoperative estimated glomerular filtration rate (eGFR) were obtained. RESULTS: Glomerular viability positively correlated with distance from tumor with mean viable glomeruli in successive 0.25-cm increments of 0-0.25 cm, 58%; 0.25-0.5 cm, 80%; 0.5-0.75 cm, 90%; and 0.75-1.0 cm, 92%. Glomerular viability near the tumor did not correlate with preoperative eGFR, whereas decreased viability further from the tumor did correlate with worse preoperative eGFR. Tumor size showed a nonstatistically significant positive trend with minimum (median 0.15 cm) and maximum margin (median 0.7 cm) sizes. Percent change of glomerular filtration rate did not correlate with margin size (P = .190). CONCLUSION: Renal parenchyma immediately adjacent to RCC contains fewer viable glomeruli compared with the parenchyma further from the tumor. Based on this information, attempts to preserve all non-neoplastic renal parenchyma via a surgical margin approaching zero may not necessarily result in clinically relevant differences in the amount of viable glomeruli remaining or the renal function preserved.

Clinical pathway after robotic nephroureterectomy: omission of pelvic drain with next-day catheter removal and discharge.

OBJECTIVE: To determine the feasibility of applying a postoperative clinical pathway after robotic nephroureterectomy (RNU) targeting safe omission of a pelvic drain and removal of the bladder catheter on the day after surgery with hospital discharge on postoperative day 1 (POD#1). METHODS: We reviewed a prospectively collected database of all RNUs performed by a single surgeon (R.A.) since institution of our clinical pathway in 2008 that includes pelvic drain omission, bladder catheter removal the morning after surgery, and discharge on POD#1. Patient demographics, and perioperative and postoperative outcomes were evaluated. Ability to adhere to the pathway and achieving the described parameters and whether any resulting complications occurred were determined. RESULTS: RNU was performed in 29 patients with mean age and body mass index of 69 years (50-90 years) and 30 kg/m(2) (19-41 kg/m(2)), respectively. No patient required a pelvic drain, and 2 were discharged with a catheter. All but 2 patients (93%) were discharged on POD#1. Overall, successful pathway application was achieved in 26 of 29 patients (90%) including no drain, catheter removal on the morning after surgery, and discharge on POD#1. No patient developed urine leak or other complications related to early catheter removal. CONCLUSION: Our clinical pathway after RNU allows safe omission of a pelvic drain with early discontinuation of the bladder catheter and discharge on the POD#1 in most patients. To our knowledge, similar pathways have not been previously achieved with nephroureterectomy by any approach, but should be considered by surgeons treating urothelial carcinoma of the upper urinary tract.

Optimization of near infrared fluorescence tumor localization during robotic partial nephrectomy.

PURPOSE: Near infrared fluorescence allows the differentiation of tumors and normal parenchyma during robotic partial nephrectomy. This may facilitate tumor excision but requires proper dosing of indocyanine green. Under dosing causes inadequate fluorescence of peritumor parenchyma. Overdosing causes tumors to fluoresce inappropriately. Currently there are no described dosing strategies to our knowledge to optimize near infrared fluorescence and reported doses vary widely. We devised a dosing strategy and assessed the reliability of near infrared fluorescence for differential fluorescence. MATERIALS AND METHODS: Robotic partial nephrectomy with near infrared fluorescence was performed for 79 tumors. Dosing strategy involved at minimum 2 indocyanine green doses, including the test dose and the calibrated dose before resection. The test dose was deliberately low to avoid confounding over-fluorescence. The second dose was calibrated depending on the extent of differential fluorescence achieved with the test doses. Intraoperative assessment of tumor fluorescence was recorded before pathological assessment. RESULTS: Mean tumor size was 3.5 cm (range 1.1 to 9.8) with a mean R.E.N.A.L. score of 8 (range 4 to 12). Median indocyanine green test dose and re-dose before clamping were 1.25 mg (range 0.625 to 2.5) and 1.875 mg (range 0.625 to 5), respectively. Differential fluorescence was achieved in 65 of 79 tumors (82%) that did not fluoresce. After 3 exclusions for the inability to assess fluorescence or indeterminate histology, 60 of 76 tumors were renal cell carcinoma. Of 60 renal cell carcinomas 55 behaved appropriately and did not fluoresce (92%). Overall 65 of 76 tumors behaved appropriately for an 86% agreement between histology and near infrared fluorescence behavior. CONCLUSIONS: With our dosing regimen near infrared fluorescence was highly reliable in achieving differential fluorescence of kidney and renal cell carcinomas. Standardized dosing is needed before deciding whether near infrared fluorescence improves robotic partial nephrectomy outcomes and additional studies may further improve reliability.

Risk and prevention of acute urinary retention after robotic prostatectomy.

PURPOSE: Acute urinary retention after catheter removal is a recognized complication following open or robot-assisted radical prostatectomy. We evaluated patient and surgery related risk factors to determine whether acute urinary retention could be prevented. To our knowledge this has not previously been investigated for prostatectomy done by any technique. MATERIALS AND METHODS: We reviewed a single surgeon, robot-assisted radical prostatectomy database of patients treated between February 2008 and June 2011 for acute urinary retention after catheter removal, which was routinely performed 3 to 7 days postoperatively. We compared the characteristics of patients with and without acute urinary retention. RESULTS: Of 1,026 patients 25 (2.4%) experienced acute urinary retention. There was no difference between patients with and without acute urinary retention in mean age, body mass index, blood loss or prostate size, and no difference in the frequency of bladder neck reconstruction or nerve sparing. The catheter was removed an average of 4.1 vs 5.7 days postoperatively in patients with vs without acute urinary retention. Of 25 patients with acute urinary retention 22 (88%) underwent catheter removal on postoperative day 3 or 4. Although only 3 of 381 patients (0.8%) had a leak on cystogram on postoperative day 3 or 4, the acute urinary retention rate when the catheter was removed on day 3 or 4 was 5.8% (22 of 381). This was several times higher than the rate in patients who retained the catheter for greater than 4 days (3 of 645 or 0.5%). CONCLUSIONS: Acute urinary retention develops infrequently after robotic prostatectomy. No patient related risk factors were identified beyond catheterization time. Although the catheter may be removed after 3 or 4 days with rare leaks, the acute urinary retention risk was much less when the catheter was left in place at least 5 days.

Evaluation of a new 240-µm single-use holmium:YAG optical fiber for flexible ureteroscopy.

BACKGROUND AND PURPOSE: Numerous holmium:yttrium-aluminum-garnet laser fibers are available for flexible ureteroscopy. Performance and durability of fibers can vary widely among different manufacturers and their product lines with differences within a single product line have been reported. We sought to evaluate a newly developed nontapered, single-use 240-µm fiber, Flexiva™ 200 (Boston Scientific, Natick, MA), during clinical use and in a bench-testing model. MATERIALS AND METHODS: A total of 100 new fibers were tested after their use in 100 consecutive flexible ureteroscopic lithotripsy procedures by a single surgeon (B.K.). Prospectively recorded clinical parameters were laser pulse energy and frequency settings, total energy delivered and fibers failure. Subsequently, each fiber was bench-tested using an established protocol. Parameters evaluated for were fibers true diameter, flexibility, tip degradation, energy transmission in straight and 180° bend configuration and fibers failure threshold with stress testing. RESULTS: The mean total energy delivered was 2.20 kJ (range 0-18.24 kJ) and most common laser settings used were 0.8 J at 8 Hz, 0.2 J at 50 Hz, and 1.0 J at 10 Hz, respectively. No fiber fractured during clinical procedures. The true fiber diameter was 450 µm. Fiber tips burnt back an average of 1.664 mm, but were highly variable. With laser setting of 400 mJ at 5 Hz, the mean energy transmitted was 451 and 441 mJ in straight and 180° bend configuration, respectively. Thirteen percent of fibers fractured at the bend radius of 0.5 cm with a positive correlation to the total energy transmitted during clinical use identified. CONCLUSION: Fiber performance was consistent in terms of energy transmission and resistance to fracture when activated in bent configuration. Fiber failure during stress testing showed significant correlation with the total energy delivered during the clinical procedure. The lack of fiber fracture during clinical use may reduce the risk of flexible endoscope damage due to fiber failure.

Regaining candidacy for heart transplantation after robotic assisted laparoscopic radical prostatectomy in left ventricular assist device patient.

Several factors may highlight the relevance of prostate cancer to the pre-heart-transplant population. First, the expansion in candidate selection criteria led to increased number of men over the age of fifty to be considered for heart transplantation. With the introduction of left ventricular assist device (LVAD) therapy, waiting-list mortality has dramatically declined over the past decade. Additionally, transplant candidates are diligently screened for preexisting neoplasm while on the waiting list. Taken together, screening-detected prostate cancer may increasingly be diagnosed in patients on the waiting list. If discovered, it will pose unique challenge to clinicians as to date there has been no universally accepted management guideline. We report a case of LVAD-treated heart transplant candidate diagnosed with prostate cancer while on the waiting list. Patient screening demonstrated PSA elevation which prompted prostate biopsy. Low-risk clinically localized prostate cancer was confirmed and led to removal of patient from transplant list. When counseled regarding management of his cancer, the patient elected to undergo radical prostatectomy in a hope to regain candidacy for heart transplantation. Despite being of high surgical risk, multidisciplinary team approach led to successful management of prostate cancer and the patient eventually received heart transplant one year following prostatectomy.

Feasibility of robotic-assisted laparoscopic nephroureterectomy in left ventricular assist device patient.

Left ventricular assist devices (LVADs) have revolutionized management options for patients with advanced heart failure. It is not uncommon for patients treated with these devices to present with noncardiac surgical conditions including urologic problems. Maintaining perioperative hemodynamic and hematologic stability is a special challenge. The minimally invasive surgery provides well-documented advantages over the open approach including a less operative blood loss and faster convalescence. In carefully selected patients, robotic-assisted surgery can be utilized in the management of patients with complex urologic diseases in a dire need for these benefits. We present the first case of robotic-assisted laparoscopic nephroureterectomy (RANU) with retroperitoneal lymph node dissection for upper tract transitional cell carcinoma (TCC) in a patient treated with LVAD.