Obesometric factors associated with increased skin-to-stone distances in renal stone patients

INTRODUCTION

Obese patients are at increased risk for renal stones as well as treatment failures due to increased skin-to-stone distances (SSD) and harder stone compositions. We investigated the relationships between obesometric parameters (body mass index [BMI], body fat distribution and obesity-related hormone levels) with SSD and stone hardness.

MATERIALS AND METHODS

We prospectively enrolled patients undergoing stone interventions at our institution. Computed tomography (CT) scans were analyzed; adipose tissue was identified according to Hounsfield units (HU) and separated into subcutaneous (SAT) and visceral (VAT) components. The pixels were averaged at three levels to calculate fat distribution: %VAT = (VAT)/(VAT + SAT). SSD was measured and HU were used as a surrogate for stone hardness. Obesity-related hormones leptin and adiponectin were measured by ELISA.

RESULTS

Seventy-nine patients were prospectively enrolled. Mean BMI and %VAT were 30.02 kg/m2 and 40.13 kg/m2. Mean leptin and adiponectin levels were 17.5 ng/mL and 7.67 mcg/mL indicating high risk for metabolic consequences of obesity. Females had greater proportions of subcutaneous fat than males (%VAT 28.4 versus 46.94, p < 0.001) and greater SSD (11.26 cm versus 9.86 cm, p = 0.025). Among obese patients, subcutaneous fat correlated with SSD independently of BMI (r = 0.454, p = 0.008). Obese patients with %VAT > 40 versus < 40 had SSD of 11.35 cm versus 13.7 cm (p = 0.005). Diabetics had harder stone compositions as measured by HU than non-diabetics (982.86 versus 648.86, p = 0.001).

CONCLUSION

Obesometric parameters such as BMI, body fat distribution, and the presence of diabetes mellitus are important considerations in the management of renal stone disease. A large proportion of subcutaneous fat, which can be estimated by physical examination, predicts SSD among obese patients and may aid treatment decisions in patients, particularly those without pre-treatment CT scans. Further studies are needed to refine the role of obesometrics in personalizing treatment decisions.

Metabolic features of clear-cell renal cell carcinoma: mechanisms and clinical implications

Central to the malignant behaviour that endows cancer cells with growth advantage is their unique metabolism. Cancer cells can process nutrient molecules differently from normal cells and use it to overcome stress imposed on them by various therapies. This metabolic conversion is controlled by specific genetic mutations that are associated with activation of oncogenes and loss of tumour suppressor proteins. Understanding these processes is important as it can lead to the discovery of biomarkers that can predict the aggressiveness of the disease and its response to therapy, and even more importantly, to the development of novel therapeutics. A classic tumour in this respect is clear-cell renal cell carcinoma (RCC). In this review, we will begin with a brief summary of normal cellular bioenergetic pathways, which will be followed by a description of the characteristic metabolism of glucose and lipids in clear-cell RCC cells and its clinical implications. Data relating to the potential effect of dietary nutrients on RCC will also be reviewed along with potential therapies targeted at interrupting specific metabolic pathways in clear-cell RCC.

The clinical importance of visceral adiposity: a critical review of methods for visceral adipose tissue analysis

As a result of the rising epidemic of obesity, understanding body fat distribution and its clinical implications is critical to timely treatment. Visceral adipose tissue is a hormonally active component of total body fat, which possesses unique biochemical characteristics that influence several normal and pathological processes in the human body. Abnormally high deposition of visceral adipose tissue is known as visceral obesity. This body composition phenotype is associated with medical disorders such as metabolic syndrome, cardiovascular disease and several malignancies including prostate, breast and colorectal cancers. Quantitative assessment of visceral obesity is important for evaluating the potential risk of development of these pathologies, as well as providing an accurate prognosis. This review aims to compare different methods of measuring visceral adiposity with emphasis on their advantages and drawbacks in clinical practice.

Construction of tissue micro array from prostate needle biopsies using the vertical clustering re-arrangement technique

BACKGROUND

Tissue microarray (TMA) allows for simultaneous rapid expression analysis of multiple molecular targets in many tissue specimens. TMA's are specifically in demand for the screening for diagnostic and prognostic markers in prostate cancer (PC). Consequently, TMAs from prostate needle biopsy (PNB) material taken at diagnosis before any treatment commenced are in demand. However, since PNB contain only limited amount of tumor arranged within a very thin tissue core, TMA construction from PNB is problematic.

METHODS

Archival PNB from 30 PC patients with variable Gleason scores (6-10) and % of cores involvement (30-90%) were used. Following selection of representative cores, the paraffin blocks were melted. Each core was sectioned into equal parts of 3-4 mm in length. For each case, a group of fragments was then re-embedded in a vertical orientation. Using Manual TMA Apparatus, 2 mm cores from each of the vertically rearranged fragments were harvested. Sections (4 µm) were stained with H&E and with high-molecular weight cytokeratin (HMWCK), PIN-cocktail (p63 + p504S), and PSA immunohistochemical stains.

RESULTS

A TMA from PNB with a capacity of 80 serial 4 µm sections was constructed. In all cases, identical tumor and neighboring tissue morphology (atrophic changes and high-grade prostatic intra-epithelial neoplasia) with no loss of tissue was evident.

CONCLUSIONS

The vertical clustering re-arrangement (VCR) technique is suitable for large scale construction of TMA blocks from PNB maintaining the morphological and immunohistochemical characteristics of the original samples. This method is promising both in terms of archival tissue preservation and biomarkers research.

Inter-related in vitro effects of androgens, fatty acids and oxidative stress in prostate cancer: a mechanistic model supporting prevention strategies

Oxidation of mitochondrial fatty acids (FA) results in the generation of reactive oxygen species (ROS) which have been postulated to play a key role in the initiation and progression of prostate cancer (PC). We previously reported that androgens increase FA uptake into PC cells. We thus examined if androgens that are known to induce ROS generation regulate FA oxidation in PC cells. The effects of the androgen-depleted medium, R1881 (synthetic androgen) and/or androgen receptor blocker, bicalutamide were examined in the human androgen-responsive but not dependent 22rv1 cells. R1881 supplementation significantly increased mitochondrial FA oxidation ((14)C-radiolabeled FA degradation studies), resulting in increased ROS production. Androgens increased the mRNA levels of carnitine palmitoyltransferase (CPT1), the rate limiting enzyme in the process of mitochondrial FA oxidation. Treatment with R1881 and bicalutamide inhibited these androgen regulated effects. Inhibition of mitochondrial ROS generation by two different inhibitors, rotenone and thenoyltrifluoroacetone, eliminated the androgen-induced ROS generation, to the same level as in cells deprived of androgens or treated with R1881 and bicalutamide. Taken together, androgens increase the mitochondrial oxidation of FA, leading to increased production of ROS that is associated with prostate cell proliferation and mutagenesis. These results therefore support the rationale for PC prevention using 5-alpha reductase inhibitors, dietary restrictions or anti-oxidants, each of which has different inhibitory but complementary effects.

Abstract 5099: Adiponectin inhibits oxidative stress in prostate cancer cells

INTRODUCTION AND OBJECTIVES: Emerging data suggest that obesity increases the risk of aggressive prostate cancer (PC) but the mechanisms underlying this relationship remain to be fully elucidated. Adiponectin, an adipocyte-specific hormone, circulates at relatively high levels in healthy human but its levels are reduced in obesity. Case control studies have documented an association between lower adiponectin blood levels and PC implying that obese individuals with low adiponectin levels are more susceptible in developing PC. In this study we examined the effect of adiponectin on the generation and reduction of oxidative stress (OS) in PC cells, a process that intimately relates to the initiation and development of PC.

METHOD: As models we used two human PC cell lines (22rv1 and DU145) expressing the adiponectin receptors AdipoR1, AdipoR2 and T-cadherin. Cells were treated with increasing doses of human recombinant adiponectin (0-40μg/ml) and were subjected to the following tests: Quantification of cellular OS (NBT reduction assay), expression of catalase and MnSOD (Western blot analysis), comparison of transcript levels of NADPH oxidases (NOX) enzymes- a major source of reactive oxygen species in PC cells (RT-PCR) and determination of the global cellular anti-oxidative capacity and catalase activity (colorimetric assays).

RESULT: Adiponectin significantly inhibited OS in both cell types in a dose dependent manner by inducing the expression of the two key anti-oxidative enzymes; catalase and MnSOD, leading to an increase in the anti-oxidative capacity of the cells. Treatment with adiponectin reduced Nox 2,4 mRNA expression in Du145 cells but increased it in 22RV1 cells.

CONCLUSIONS: These results suggest a protective role for adiponectin against the initiation and development of PC, through OS inhibition.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5099.

Abstract 70: Mitochondrial localization of adiponectin receptor 1 (AdipoR1) induces apoptosis in cancer cells

INTRODUCTION

Previous studies by us and others demonstrated tumor suppressive effects of adiponectin, an adipocyte derived hormone. Adiponectin signaling occurs through two distinct membrane receptors; AdipoR1 and AdipoR2. There is paucity of data how their activation leads to tumor suppression. Here we present data indicating localization of AdipoR1 to the mitochondria and its role in apoptosis of cancer cells.

MATERIALS AND METHODS

Human kidney (RCC1932) and cervical (HeLa CCL-2) cancer cells as well as human embryonic kidney cells (HEK 293) were used as models. Full length AdipoR1 and its N-terminal (ligand binding) and C-terminal (intracellular moiety) truncated mutants (mutAdipoR1) ORFs were subcloned into YFP expressing vectors (pEYFP- AdipoR1, pEYFPmutAdipoR1). Cells were seeded onto glass cover slips in multi-well culture plates and transfected with vectors through Lipofectamine-2000 (Invitrogen) method 24 h after seeding. The effect of adiponectin (BioVendor) supplementation was also tested. Immunocytochemistry staining were with MitoTracker labeling or anti-MnSOD (mitochondria), anti-Stearoyl-CoA desaturase (SCD-1, ER), anti-Reb5, anti-manose-6-phosphatase receptor (M6P, endosome); or anti-Catalase (peroxisome). Images of the cells were collected with DM IRB Deconvolution Microscope (Leica) or Confocal microscope LSM510 (Carl Zeiss). Apoptosis was determined by sub-diploid population detection and or annexin binding using flow cytometry.

RESULTS

Over-expression of AdipoR1 in the cells induced apoptosis which was further augmented by adiponectin treatment. This was evident only in cells expressing full length AdipoR1. Furthermore, cells expressing mutAdipoR1 had different intracellular distributions with loss of mitochondrial localization of the receptor and pro-apoptotic activity.

CONCLUSIONS

This is the first report showing that AdipoR1 can be localized in the mitochondria. Adiponectin induce apoptosis in cancer cells through mitochondrial localization related mechanism that requires both ligand and signaling domains of AdipoR1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 70.

Obesity and renal cell carcinoma: epidemiology, underlying mechanisms and management considerations

The incidence of both renal cell carcinoma (RCC) and obesity are steadily rising in Western societies. Recent studies have established that obesity is a significant risk factor for the development of several malignancies, including RCC. However, the mechanisms underlying this relationship remain to be fully elucidated. We review herein the epidemiological links between obesity and RCC, the potential mechanisms by which obesity can influence RCC development and progression, and the special considerations related to the treatment of obese patients with RCC.

Androgens induce oxidative stress and radiation resistance in prostate cancer cells though NADPH oxidase

Androgen deprivation therapy (ADT) facilitates the response of prostate cancer (PC) to radiation. Androgens have been shown to induce elevated basal levels of reactive oxygen species (ROS) in PC, leading to adaptation to radiation-induced cytotoxic oxidative stress. Here, we show that androgens increase the expression of p22^phox and gp91^phox subunits of NADPH oxidase (NOX) and ROS production by NOX2 and NOX4 in PC. Pre-radiation treatment of 22Rv1 human PC cells with NOX inhibitors sensitize the cells to radiation similarly to ADT, suggesting that their future usage may spare the need for adjuvant ADT in PC patients undergoing radiation.

Androgen-dependent regulation of medium and long chain fatty acids uptake in prostate cancer

BACKGROUND

Epidemiological and experimental studies suggest that both fatty acids and androgens have a role in the development and progression of prostate cancer (PC). Plasma membrane fatty acid binding protein (FABP(pm)) is a transporter of medium and long chain fatty acids (MCFA and LCFA) across the plasma membrane, and is identical to the mitochondrial protein aspartate aminotransferase (mAAT) that is regulated by testosterone only in prostate epithelial cells, a site where PC initially develops. We therefore hypothesized that FABP(pm) is also regulated by androgens.

METHODS

We examined the effect of a synthetic androgen, R1881, and that of androgen receptor (AR) blocker, bicalutamide, on the expression of FABP(pm) and mAAT and on the uptake of fatty acids in the androgen-sensitive LNCaP, androgen responsive 22rv1 and androgen-independent CL1 human PC cells. This was done using immunofluorescence and confocal microscopy, Western blot, flow cytometry, and (3)H-oleate uptake studies.

RESULTS

Androgen supplementation increased the cellular and surface expression of FABP(pm) and mAAT and increased the uptake of fluorescently labeled MCFA and LCFA and that of (3)H-oleate only in PC cells that express the AR. Bicalutamide inhibited this phenomenon.

CONCLUSIONS

The uptake of MCFA and LCFA into PC cells is androgen regulated as well as the expression of FABP(pm) and mAAT.

Diagnosis of prostate cancer

The contemporary challenge of prostate cancer diagnosis has been changed in the past decade from the endeavor to increase detection to that of detecting only those tumors that are clinically significant. Better interpretation of the role of prostate-specific antigen (PSA) and its kinetics as a diagnostic tool, the adoption of extended prostate biopsy schemes, and perhaps implementation of new transrectal ultrasound (TRUS) technologies promote the achievement of this clinical mission. This chapter reviews these issues as well as the change in practice of patient preparation for TRUS-biopsy and analgesia during it, the role of repeat and saturation prostate biopsies, and the interpretation of an incidental prostate cancer finding. Currently, the lifetime risk of a diagnosis of prostate cancer for North American men is 16%, compared to the lifetime risk of death from prostate cancer, which is 3% (Carter 2004). The advent of prostate-specific antigen (PSA) screening and transrectal ultrasonography (TRUS) has significantly impacted the detection of prostate cancer over the last 20 years. The mean age at diagnosis has decreased (Hankey et al. 1999; Stamey et al. 2004) and the most common stage at diagnosis is now localized disease (Newcomer et al. 1997; Stamey et al. 2004). The goal of prostate cancer screening is to detect only those men at risk for death from the disease at an early curable phase. The ambiguous natural history of this most common malignancy in men, being latent with questionable life-threatening potential in a large number of cases on the one hand, with only a relatively small number (though not negligible) of highly malignant cases on the other, propels many doubts about whether this is possible. This was famously phrased more than 20 years ago by Whitmore who asked: "Is cure possible for those in whom it is necessary; and is it necessary for those in whom it is possible?" This is probably even more relevant nowadays. During the past decade two factors influenced significantly the increased detection rate of prostate cancer in general and that of clinically insignificant prostate cancers in particular: the widespread use of serum PSA as a screening tool to a large extent and to a lesser though significant extent the application of extended multiple core biopsy schemes (Master et al. 2005). In fact, 75% of men in the United States aged 50 years and older have been screened with the PSA test (Sirovich et al. 2003). Outside of the screening context, which is dealt with in depth in Chap. 5, clinical suspicion of prostate cancer is raised usually by abnormal digital rectal examination (DRE) and/or by abnormal levels of serum PSA. Final diagnosis is achieved only based on positive prostate biopsies.

Androgen induces adaptation to oxidative stress in prostate cancer: implications for treatment with radiation therapy

Radiation therapy is a standard treatment for prostate cancer (PC). The postulated mechanism of action for radiation therapy is the generation of reactive oxygen species (ROS). Adjuvant androgen deprivation (AD) therapy has been shown to confer a survival advantage over radiation alone in high-risk localized PC. However, the mechanism of this interaction is unclear. We hypothesize that androgens modify the radioresponsiveness of PC through the regulation of cellular oxidative homeostasis. Using androgen receptor (AR)(+) 22rv1 and AR(-) PC3 human PC cell lines, we demonstrated that testosterone increased basal reactive oxygen species (bROS) levels, resulting in dose-dependent activation of phospho-p38 and pAKT, and increased expression of clusterin, catalase, and manganese superoxide dismutase. Similar data were obtained in three human PC xenografts; WISH-PC14, WISH-PC23, and CWR22, growing in testosterone-supplemented or castrated SCID mice. These effects were reversible through AD or through incubation with a reducing agent. Moreover, testosterone increased the activity of catalase, superoxide dismutases, and glutathione reductase. Consequently, AD significantly facilitated the response of AR(+) cells to oxidative stress challenge. Thus, testosterone induces a preset cellular adaptation to radiation through the generation of elevated bROS, which is modified by AD. These findings provide a rational for combined hormonal and radiation therapy for localized PC.