Periprostatic fat correlates with tumour aggressiveness in prostate cancer patients

Inorganic Arsenic-Related Changes in the Stromal Tumor Microenvironment in a Prostate Cancer Cell-Conditioned Media Model

BACKGROUND

The tumor microenvironment plays an important role in the progression of cancer by mediating stromal-epithelial paracrine signaling, which can aberrantly modulate cellular proliferation and tumorigenesis. Exposure to environmental toxicants, such as inorganic arsenic (iAs), has also been implicated in the progression of prostate cancer.

OBJECTIVE

The role of iAs exposure in stromal signaling in the tumor microenvironment has been largely unexplored. Our objective was to elucidate molecular mechanisms of iAs-induced changes to stromal signaling by an enriched prostate tumor microenvironment cell population, adipose-derived mesenchymal stem/stromal cells (ASCs).

RESULTS

ASC-conditioned media (CM) collected after 1 week of iAs exposure increased prostate cancer cell viability, whereas CM from ASCs that received no iAs exposure decreased cell viability. Cytokine array analysis suggested changes to cytokine signaling associated with iAs exposure. Subsequent proteomic analysis suggested a concentration-dependent alteration to the HMOX1/THBS1/TGFβ signaling pathway by iAs. These results were validated by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, confirming a concentration-dependent increase in HMOX1 and a decrease in THBS1 expression in ASC following iAs exposure. Subsequently, we used a TGFβ pathway reporter construct to confirm a decrease in stromal TGFβ signaling in ASC following iAs exposure.

CONCLUSIONS

Our results suggest a concentration-dependent alteration of stromal signaling: specifically, attenuation of stromal-mediated TGFβ signaling following exposure to iAs. Our results indicate iAs may enhance prostate cancer cell viability through a previously unreported stromal-based mechanism. These findings indicate that the stroma may mediate the effects of iAs in tumor progression, which may have future therapeutic implications.

CITATION

Shearer JJ, Wold EA, Umbaugh CS, Lichti CF, Nilsson CL, Figueiredo ML. 2016. Inorganic arsenic-related changes in the stromal tumor microenvironment in a prostate cancer cell-conditioned media model. Environ Health Perspect 124:1009-1015; http://dx.doi.org/10.1289/ehp.1510090.

Periprostatic adipocytes act as a driving force for prostate cancer progression in obesity

Obesity favours the occurrence of locally disseminated prostate cancer in the periprostatic adipose tissue (PPAT) surrounding the prostate gland. Here we show that adipocytes from PPAT support the directed migration of prostate cancer cells and that this event is strongly promoted by obesity. This process is dependent on the secretion of the chemokine CCL7 by adipocytes, which diffuses from PPAT to the peripheral zone of the prostate, stimulating the migration of CCR3 expressing tumour cells. In obesity, higher secretion of CCL7 by adipocytes facilitates extraprostatic extension. The observed increase in migration associated with obesity is totally abrogated when the CCR3/CCL7 axis is inhibited. In human prostate cancer tumours, expression of the CCR3 receptor is associated with the occurrence of aggressive disease with extended local dissemination and a higher risk of biochemical recurrence, highlighting the potential benefit of CCR3 antagonists in the treatment of prostate cancer.

Linking obesogenic dysregulation to prostate cancer progression

The global epidemic of obesity is closely linked to the development of serious co-morbidities, including many forms of cancer. Epidemiological evidence consistently shows that obesity is associated with a similar or mildly increased incidence of prostate cancer but, more prominently, an increased risk for aggressive prostate cancer and prostate cancer-specific mortality. Studies in mice demonstrate that obesity induced by high-fat feeding increases prostate cancer progression; however, the mechanisms underpinning this relationship remain incompletely understood. Adipose tissue expansion in obesity leads to local tissue dysfunction and is associated with low-grade inflammation, alterations in endocrine function and changes in lipolysis that result in increased delivery of fatty acids to tissues of the body. The human prostate gland is covered anteriorly by the prominent peri-prostatic adipose tissue and laterally by smaller adipose tissue depots that lie directly adjacent to the prostatic surface. We discuss how the close association between dysfunctional adipose tissue and prostate epithelial cells might result in bi-directional communication to cause increased prostate cancer aggressiveness and progression. However, the literature indicates that several 'mainstream' hypotheses regarding obesity-related drivers of prostate cancer progression are not yet supported by a solid evidence base and, in particular, are not supported by experiments using human tissue. Understanding the links between obesity and prostate cancer will have major implications for the health policy for men with prostate cancer and the development of new therapeutic or preventative strategies.

Periprostatic fat thickness on MRI: correlation with Gleason score in prostate cancer

OBJECTIVE

The purpose of this study was to retrospectively evaluate the relationship between periprostatic fat thickness on MRI and Gleason score of prostate cancer using radical prostatectomy as the reference standard.

MATERIALS AND METHODS

This study included 190 patients (mean age [± SD], 66.9 ± 7.0 years) who underwent MRI before radical prostatectomy. Two radiologists measured the subcutaneous and periprostatic fat thickness on midsagittal T2-weighted MR images as the shortest perpendicular distance from the pubic symphysis to the skin and prostate, respectively. Subcutaneous and periprostatic fat along with age, height, weight, body mass index, and prostate-specific antigen (PSA) were correlated with Gleason score by using Pearson (r) or Spearman (ρ) correlation coefficients and compared between low- (Gleason score = 6) and high- (≥ 7) grade prostate cancer by using univariate and multivariate logistic regression analyses.

RESULTS

The mean subcutaneous and periprostatic fat thicknesses were 24.0 ± 8.4 mm and 5.0 ± 2.0 mm, respectively. The Gleason score was significantly correlated with age (ρ = 0.181, p = 0.012), PSA (ρ = 0.345, p < 0.001), and periprostatic fat thickness (ρ = 0.228, p = 0.002). Multivariate analysis revealed that age, height, PSA level, and periprostatic fat thickness (odds ratio, 1.331; 95% CI, 1.063-1.666) were independently predictive of high-grade (p ≤ 0.013) disease.

CONCLUSION

Periprostatic fat thickness on MRI showed a mild to modest but significant correlation with Gleason score of prostate cancer with radical prostatectomy as the reference standard and was an independent predictive factor for high-grade prostate cancer.

MRS measured fatty acid composition of periprostatic adipose tissue correlates with pathological measures of prostate cancer aggressiveness

PURPOSE

To investigate the association between magnetic resonance (MR) spectroscopically measured fatty acid composition of periprostatic adipose tissue and pathological markers of prostate cancer aggressiveness.

MATERIALS AND METHODS

Periprostatic adipose (PPA) and subcutaneous adipose (SQA) tissue from prostate cancer patients undergoing radical prostatectomy were examined ex vivo by proton MR spectroscopy at 14.1T (n = 31). Fractions of monounsaturated, polyunsaturated, total unsaturated, and saturated fatty acids, as well as T2 relaxation times were measured from the spectra. Univariate and multivariate analyses based on receiver operating characteristic (ROC) and support vector machines (SVM) were used to evaluate the association between differential measures of fatty acid levels in the PPA and SQA tissues and Gleason score and extracapsular extension (ECE), which are pathological measures of prostate cancer aggressiveness.

RESULTS

Both pathological markers for aggressive prostate cancer have separable patterns in the MRS features space. The association between ECE and PPA tissue fatty acid composition is linear (area under receiver operating characteristic curve (AROC) and 95% confidence intervals [CIs]: 1.00, [1.00, 1.00]), along the Δ(fM /fS ) measure, and is marked by elevated monounsaturated and reduced saturated fatty acids in the PPA tissue relative to SQA. In contrast, the association between Gleason score and PPA tissue fatty acid composition is nonlinear (classifier AROC and 95% CIs: 0.86, [0.71, 1.00]).

CONCLUSION

Fatty acid composition is altered in the PPA tissue of patients with aggressive prostate cancer. Ex vivo MR spectroscopy may be a useful tool in studying the altered fatty acid metabolism in prostate cancer.

Is periprostatic adipose tissue associated with aggressive tumor biology in prostate cancer?

The prevalence of overweight and obesity and their health-related problems have been increasing. Obesity is increasingly recognized as a risk factor in different types of cancer in humans. The mechanisms supporting the link between obesity and cancer development have not been fully understood. Leptin, a circulating cytokine produced by adipocytes, may influence prostate cancer (PCa) progression in different ways. Body mass index seems to be an unreliable predictor for the development of PCa, but its influence on progression and poor oncological outcomes seems to be clear. Given the fact that abdominal fat is the most metabolically active fat, with different metabolic and paracrine effects, related anthropometric measurements may lead to a better estimation of PCa risk. Metabolically active periprostatic abdominal fat may also play an important role in releasing cytokines and growth factors that may promote tumor cell proliferation or even create a favorable environment for aggressive tumor biology. Different imaging measurements, e.g., periprostatic adipose tissue (PPAT) thickness, may be significant predictors of PCa. Several genes in the PPAT of obese men have been identified to contribute to chronic immuno-inflammatory responses which eventually lead to cell cycle alteration with oncological potential. In vitro studies showed the importance of PCa and its interaction with its microenvironment particularly in patients with aggressive PCa. Different types of cytokines, such as interleukin-6, may promote a tumorigenic microenvironment. This article endeavors to review the current literature on the association of PPAT with aggressive tumor biology in PCa.

Body Mass Index and Doses at Organs at Risk in a Mediterranean Population Treated with Postoperative Vaginal Cuff Brachytherapy

Purpose

Association between body mass index (BMI) and doses in organs at risk during postoperative vaginal cuff brachytherapy (VCB) treatment has not been evaluated. The aim of this study was to analyse the impact of BMI on the dose delivered to bladder and rectum during high-dose-rate VCB using computed tomography (CT) scans at every fraction.

Materials and Methods

A retrospective analysis of 220 planning CT sets derived from 59 patients was conducted. Every planning CT was re-segmented and re-planned under the same parameters. Rectum and bladder dose-volume histogram values (D_0.1cc, D_1cc, and D_2cc) were extracted and evaluated. The mean values for all applications per patient were calculated and correlated with BMI, as well as other factors influencing rectal and bladder doses. Multiple regression analysis performed to model organ at risk dose-volume parameters.

Results

According to World Health Organization (WHO), 6.8% of patients were normal, 35.6% were overweight, and 57.6% were class I obese. Median rectal doses were 133.5%, 110.9%, and 99.3% for D_0.1cc, D_1cc, and D_2cc, respectively. The corresponding median bladder doses were 96.2%, 80.6%, and 73.3%, respectively. BMI did not show significant association with rectal doses. However, BMI did show a significant association with evaluated bladder dose metrics (D_0.1cc, r=–0.366, p=0.004; D_1cc, r=–0.454, p < 0.001; D_2cc, r=–0.451, p < 0.001). BMI was retained in the multivariate regression models (D_0.1cc, p=0.004; D_1cc, p < 0.001; D_2cc, p=0.001).

Conclusion

In this group of Mediterranean, overweight, and moderately obese patients, BMI showed association with lower bladder dose values, but not with rectal doses.

Influence of adipocytokines and periprostatic adiposity measurement parameters on prostate cancer aggressiveness

BACKGROUND

The relationship between obesity and prostate cancer aggressiveness is controversial in recent studies, partly because BMI is the only generally applied marker of obesity. Our study aimed at evaluating the correlation of periprostatic fat (PF) on magnatic resonance imaging (MRI) and adipocytokines with prostate cancer aggressiveness.

PATIENTS AND METHOD

A total of 184 patients who underwent radical retropubic prostatectomy (RRP) were analyzed retrospectively; different fat measurements on MRI slices and levels of adipocytokines were compared with the clinical and pathologic factors using SSPS ver.13.0.

RESULT

The PF rates showed a statistically significant variation (p=0.019, 0.025) among groups, that is to say, more adipose tissue was distributed in periprostatic areas of high risk patients. Logistic regression analysis adjusted for age revealed a statistically association between the PF, the ratio and the risk of having high-risk disease (p=0.031, 0.024). The levels of IL-6, leptin and c-reactive protein (CRP) significantly increased with the aggressiveness of prostate cancer, and also with PF and its ratio. The strongest correlation was seen between IL-6 and PF (Pearson r coefficient=0.67, P<0.001). No association was observed between adipocytokines and BMI.

CONCLUSION

Periprostatic adiposity not only affects prostate cancer aggressiveness, but also influences the secretion of adipocytokines. IL-6, PF and CRP have promoting effects on progression of prostate cancer.

Racial differences in adipose tissue distribution and risk of aggressive prostate cancer among men undergoing radiotherapy

BACKGROUND

Although elevated body mass index (BMI) has been associated with increased risk of aggressive prostate cancer, the importance of adipose tissue distribution is not well understood. We examined associations between overall and visceral obesity and aggressive prostate cancer risk. Moreover, given racial differences in adipose tissue distribution, we examined whether race modified these associations.

METHODS

We conducted a cross-sectional analysis of 308 radiotherapy-treated patients with prostate cancer within the Durham VA from 2005 to 2011. Multivariable logistic regression examined the association between BMI categories and tertiles of waist circumference (WC), visceral fat area (VFA), and periprostatic adipose tissue area (PPAT) with high-grade prostate cancer risk (Gleason score ≥7 vs. ≤6). Models stratified by race examined whether these associations differed between black and nonblack men.

RESULTS

Both elevated BMI (Ptrend = 0.054) and WC (Ptrend = 0.040) were associated with increased high-grade prostate cancer risk, with similar results between races, although the association with BMI was not statistically significant. In contrast, elevated VFA was associated with increased aggressive prostate cancer risk in black men (Ptrend = 0.002) but not nonblack men (Ptrend = 0.831), with a significant interaction between race and VFA (Pinteraction = 0.035). Though similar patterns were observed for PPAT, none was statistically significant.

CONCLUSIONS

Among men undergoing radiotherapy for prostate cancer, visceral obesity is associated with increased aggressive prostate cancer risk, particularly among black men. If confirmed in future studies, these results suggest that adipose tissue distribution differences may contribute to prostate cancer racial disparity.

IMPACT

These findings highlight the need to elucidate mechanisms contributing to racial differences in the association between visceral obesity and aggressive prostate cancer.

Periprostatic adipose tissue from obese prostate cancer patients promotes tumor and endothelial cell proliferation: a functional and MR imaging pilot study

BACKGROUND

Obesity, particularly visceral adiposity, confers a worse prognosis for prostate cancer (PCa) patients, and increasing periprostatic adipose (PPA) tissue thickness or density is positively associated with more aggressive disease. However, the cellular mechanism of this activity remains unclear. Therefore, in this pilot study, we assessed the functional activity of PPA tissue secretions and established a biochemical profile of PPA as compared to subcutaneous adipose (SQA) tissues from lean, overweight and obese PCa patients.

METHODS

Adipose tissues were collected from PCa patients undergoing surgical prostate removal. Tissues were analyzed by histologic and magnetic resonance (MR) techniques. Explant tissue culture secretions were used in proliferation assays on PCa and endothelial cells.

RESULTS

PPA secretions obtained from obese patients were significantly more pro-proliferative in both PCa and endothelial cells as compared to PPA obtained from lean or overweight men and SQA tissues. Consistent with this, PPA microvessel density was increased, and the T2 relaxation time was decreased, compared to SQA tissues, and we observed a modest, inverse correlation between the T2 and tumor stage. Moreover, the ratio of unsaturated to saturated fatty acids, obtained using MR spectroscopy, showed a modest, inverse correlation with Gleason score.

CONCLUSIONS

These pilot data show that PPA stimulates PCa cell proliferation and angiogenesis and that obesity intensifies this activity, thus generating a mechanistic hypothesis to explain the worse prognosis observed in obese PCa patients. Our pilot study also shows that MR technology may be useful in further elucidating the relationship between obesity and PCa progression.

Unusually high prostate-specific antigen bounce after prostate brachytherapy: Searching for etiologic factors

PURPOSE

Determine whether fat distribution, body mass index, or clinical and dosimetric factors are associated with prostate specific antigen (PSA) bounce (PSAb) of ≥1.6 ng/mL in patients treated with permanent seed (125)I prostate brachytherapy (PB).

METHODS AND MATERIALS

We identified 23 patients with a PSAb of ≥1.6 ng/mL. For each patient with a bounce, at least one control with similar age (age ± 2 years, n=31) was identified. Control patients had to have no bounce (≤0.2 ng/mL) and a most recent PSA of <1 ng/mL. CT at Day 30 after PB was used to determine the volume of subcutaneous adipose tissue, visceral adipose tissue, and peri-prostatic fat. Univariate and multivariate logistic models were used to assess the association between PSAb and adipose tissue distribution and clinical and dosimetric factors.

RESULTS

Mean patient age was 62.3 ± 5.3 years. Mean PSAb height was 2.7 ± 0.8 ng/mL, and mean time to bounce was 9.6 ± 4 months. More than 90% of the patients reached a PSA nadir before PSAb within 12 months post-PB. Patients showing PSAb were more likely to have a T1c disease vs. T2a (odds ratio = 18.87; 95% confidence interval: 2.32-454.55; p=0.019) and a lower seed activity per cc of prostate volume (odds ratio=0.02; 95% confidence interval=0.42-2.22; p=0.026). Neither fat distribution nor body mass index was associated with PSAb (p=0.11-0.597).

CONCLUSIONS

Clinical and dosimetric factors play a role in PSAb of ≥1.6 ng/mL. Fat distribution is not associated with a PSAb. There is presently no satisfactory theory to explain the etiology of PSAb.

Obesity and prostate cancer: weighing the evidence

CONTEXT

Obesity and prostate cancer (PCa) affect substantial proportions of Western society. Mounting evidence, both epidemiologic and mechanistic, for an association between the two is of public health interest. An improved understanding of the role of this modifiable risk factor in PCa etiology is imperative to optimize screening, treatment, and prevention.

OBJECTIVE

To consolidate and evaluate the evidence for an epidemiologic link between obesity and PCa, in addition to examining the proposed underlying molecular mechanisms.

EVIDENCE ACQUISITION

A PubMed search for relevant articles published between 1991 and July 2012 was performed by combining the following terms: obesity, BMI, body mass index and prostate cancer risk, prostate cancer incidence, prostate cancer mortality, radical prostatectomy, androgen-deprivation therapy, external-beam radiation, brachytherapy, prostate cancer and quality of life, prostate cancer and active surveillance, in addition to obesity, BMI, body mass index and prostate cancer and insulin, insulin-like growth factor, androgen, estradiol, leptin, adiponectin, and IL-6. Articles were selected based on content, date of publication, and relevancy, and their references were also searched for relevant articles.

EVIDENCE SYNTHESIS

Increasing evidence suggests obesity is associated with elevated incidence of aggressive PCa, increased risk of biochemical failure following radical prostatectomy and external-beam radiotherapy, higher frequency of complications following androgen-deprivation therapy, and increased PCa-specific mortality, although perhaps a lower overall PCa incidence. These results may in part relate to difficulties in detecting and treating obese men. However, multiple molecular mechanisms could explain these associations as well. Weight loss slows PCa in animal models but has yet to be fully tested in human trials.

CONCLUSIONS

Obesity appears to be linked with aggressive PCa. We suggest clinical tips to better diagnose and treat obese men with PCa. Whether reversing obesity slows PCa growth is currently unknown, although it is an active area of research.

Human periprostatic white adipose tissue is rich in stromal progenitor cells and a potential source of prostate tumor stroma

A body of growing evidence now implicates white adipose tissue as a relevant source of stromal progenitor cells recruited to the tumor microenvironment to form supportive tumor stroma. While the role of periprostatic (PP) adipose tissue in prostate cancer progression has been barely appreciated, we sought to determine the progenitor cell population in PP adipose tissue and the association with prostate cancer. We isolated and characterized CD31(-)CD34(+)CD45(-)CD146(-) progenitor cells (adipose-derived stem cells [ASC]) in paired samples of PP and preperitoneal visceral adipose tissue from prostate tissue and peripheral blood mononuclear cells of prostate cancer and nodular prostatic hyperplasia patients. ASC were quantified by flow cytometry and confirmed through target gene expression. Here we show a significantly higher amount of ASC in PP than in visceral adipose tissue, independent of body mass index and prostatic disease. In the prostate, ASC are increased in cancer compared with prostatic nodular hyperplasia patients. Concordantly, adipsin gene (CFD) expression, which is known to be up-regulated in adipose stem cells, was overexpressed in PP adipose tissue, in the prostate of cancer patients and in prostate CD31(-)CD34(+)CD45(-)CD146(-) sorted cells. ASC were found at higher levels in the blood of prostate cancer patients simultaneously overweight/obese. Present findings indicate that PP adipose tissue is a reservoir of progenitor cells with the potential to migrate towards prostate tumors, although its clinical significance merits further evaluation.

Obesity and prostate cancer: gene expression signature of human periprostatic adipose tissue

BACKGROUND

Periprostatic (PP) adipose tissue surrounds the prostate, an organ with a high predisposition to become malignant. Frequently, growing prostatic tumor cells extend beyond the prostatic organ towards this fat depot. This study aimed to determine the genome-wide expression of genes in PP adipose tissue in obesity/overweight (OB/OW) and prostate cancer patients.

METHODS

Differentially expressed genes in human PP adipose tissue were identified using microarrays. Analyses were conducted according to the donors' body mass index characteristics (OB/OW versus lean) and prostate disease (extra prostatic cancer versus organ confined prostate cancer versus benign prostatic hyperplasia). Selected genes with altered expression were validated by real-time PCR. Ingenuity Pathway Analysis (IPA) was used to investigate gene ontology, canonical pathways and functional networks.

RESULTS

In the PP adipose tissue of OB/OW subjects, we found altered expression of genes encoding molecules involved in adipogenic/anti-lipolytic, proliferative/anti-apoptotic, and mild immunoinflammatory processes (for example, FADS1, down-regulated, and LEP and ANGPT1, both up-regulated). Conversely, in the PP adipose tissue of subjects with prostate cancer, altered genes were related to adipose tissue cellular activity (increased cell proliferation/differentiation, cell cycle activation and anti-apoptosis), whereas a downward impact on immunity and inflammation was also observed, mostly related to the complement (down-regulation of CFH). Interestingly, we found that the microRNA MIRLET7A2 was overexpressed in the PP adipose tissue of prostate cancer patients.

CONCLUSIONS

Obesity and excess adiposity modified the expression of PP adipose tissue genes to ultimately foster fat mass growth. In patients with prostate cancer the expression profile of PP adipose tissue accounted for hypercellularity and reduced immunosurveillance. Both findings may be liable to promote a favorable environment for prostate cancer progression.

The relationship between obesity and prostate cancer: from genetics to disease treatment and prevention

Recent studies demonstrated that obesity is associated with prostate cancer aggressiveness and prognosis. However, the mechanisms underlying this relationship are poorly understood. Tumor microenvironment has been increasingly considered as an important determinant of cancer growth and progression. In the light of this growing evidence, Ribeiro et al., in a BMC Medicine research article, investigated the gene expression profiles of periprostatic adipose tissue of obese patients with and without prostate cancer and compared them to those of lean patients. Their findings provide the first evidence of a differential gene expression in the periprostatic adipose tissue of obese individuals. Differences were also observed when comparing the periprostatic adipose tissue of patients with and without prostate cancer. Differentially expressed genes are related to cell proliferation and immunological responses. Besides suggesting the genetic bases for the observed relationship between obesity and prostate cancer aggressiveness, these findings provide new insights on the important link between local microenvironment and cancer progression.

Human periprostatic adipose tissue promotes prostate cancer aggressiveness in vitro

Background

Obesity is associated with prostate cancer aggressiveness and mortality. The contribution of periprostatic adipose tissue, which is often infiltrated by malignant cells, to cancer progression is largely unknown. Thus, this study aimed to determine if periprostatic adipose tissue is linked with aggressive tumor biology in prostate cancer.

Methods

Supernatants of whole adipose tissue (explants) or stromal vascular fraction (SVF) from paired fat samples of periprostatic (PP) and pre-peritoneal visceral (VIS) anatomic origin from different donors were prepared and analyzed for matrix metalloproteinases (MMPs) 2 and 9 activity. The effects of those conditioned media (CM) on growth and migration of hormone-refractory (PC-3) and hormone-sensitive (LNCaP) prostate cancer cells were measured.

Results

We show here that PP adipose tissue of overweight men has higher MMP9 activity in comparison with normal subjects. The observed increased activities of both MMP2 and MMP9 in PP whole adipose tissue explants, likely reveal the contribution of adipocytes plus stromal-vascular fraction (SVF) as opposed to SVF alone. MMP2 activity was higher for PP when compared to VIS adipose tissue. When PC-3 cells were stimulated with CM from PP adipose tissue explants, increased proliferative and migratory capacities were observed, but not in the presence of SVF. Conversely, when LNCaP cells were stimulated with PP explants CM, we found enhanced motility despite the inhibition of proliferation, whereas CM derived from SVF increased both cell proliferation and motility. Explants culture and using adipose tissue of PP origin are most effective in promoting proliferation and migration of PC-3 cells, as respectively compared with SVF culture and using adipose tissue of VIS origin. In LNCaP cells, while explants CM cause increased migration compared to SVF, the use of PP adipose tissue to generate CM result in the increase of both cellular proliferation and migration.

Conclusions

Our findings suggest that the PP depot has the potential to modulate extra-prostatic tumor cells' microenvironment through increased MMPs activity and to promote prostate cancer cell survival and migration. Adipocyte-derived factors likely have a relevant proliferative and motile role.

Tumor cell-educated periprostatic adipose tissue acquires an aggressive cancer-promoting secretory profile

BACKGROUND/AIMS

The microenvironment produces important factors that are crucial to prostate cancer (PCa) progression. However, the extent to which the cancer cells stimulate periprostatic adipose tissue (PPAT) to produce these proteins is largely unknown. Our purpose was to determine whether PCa cell-derived factors influence PPAT metabolic activity.

METHODS

Primary cultures of human PPAT samples from PCa patients (adipose tissue organotypic explants and primary stromal vascular fraction, SVF) were stimulated with conditioned medium (CM) collected from prostate carcinoma (PC3) cells. Cultures without CM were used as control. We used multiplex analysis and ELISA for protein quantification, qPCR to determine mitochondrial DNA (mtDNA) copy number and zymography for matrix metalloproteinase activity, in order to evaluate the response of adipose tissue explants and SVFs to PC3 CM.

RESULTS

Stimulation of PPAT explants with PCa PC3 CM induced adipokines associated with cancer progression (osteopontin, tumoral necrosis factor alpha and interleukin-6) and reduced the expression of the protective adipokine adiponectin. Notably, osteopontin protein expression was 13-fold upregulated. Matrix metalloproteinase 9 activity and mitochondrial DNA copy number were higher after stimulation with cancer CM. Stromovascular cells from PPAT in culture were not influenced by tumor-derived factors.

CONCLUSION

The modulation of adipokine expression by tumor CM indicates the pervasive extent to which tumor cells command PPAT to produce factors favorable to their aggressiveness.

Measurement of peri-prostatic fat thickness using transrectal ultrasonography (TRUS): a new risk factor for prostate cancer

Study Type - Prognosis (cohort) Level of Evidence 2b. What's known on the subject? and What does the study add? ADIPOSE tissue secretes various endocrine and paracrine mediators. Some authors have begun to consider whether peri-prostatic fat (PPF) may interact with the prostate and play a role in carcinogenesis. It has recently been shown that the PPF quantity measured by CT is associated with more aggressive disease in patients undergoing radiation therapy. Our group studied a population not yet diagnosed with prostate cancer. By doing so we were able to identify PPF thickness on transrectal ultrasonography as a risk factor for prostate cancer detection upon biopsy, and as a risk factor for high-grade disease. Our study also raises interesting questions about the underlying mechanisms of the association between PPF quantity and prostate cancer.

OBJECTIVE

To determine if the amount of peri-prostatic fat (PPF) on transrectal ultrasonography (TRUS) is a risk factor for incident prostate cancer overall and high-grade prostate cancer (Gleason ≥4).

PATIENTS AND METHODS

A prospectively maintained database of patients undergoing prostate biopsy at Princess Margaret Hospital for cancer suspicion was used. • All TRUS examinations were retrospectively reviewed upon 'blinding' to outcome. • PPF thickness, measured as the distance between the prostate and the pubic bone, was used as an index of the quantity of PPF. • PPF measurements, together with other prostate cancer risk factors, were evaluated against prostate cancer and high-grade prostate cancer detection upon biopsy with univariable and multivariable logistic regression and area under the receiver operating characteristic curve (AUC) analysis.

RESULTS

Of the 931 patients, 434 (47%) were diagnosed with prostate cancer and 218 (23%) were diagnosed with high-grade prostate cancer. • The mean (range) PPF thickness was 5.3 (0-15) mm. • Increasing PPF thickness was associated with prostate cancer and high-grade prostate cancer diagnosis, with graded effect. When adjusting for other variables, the odds of detecting any prostate cancer and high-grade prostate cancer increased 12% (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.02-1.23) and 20% (OR 1.20, 95% CI 1.07-1.34), respectively, for each millimetre increase in PPF thickness. • The AUCs for the association of PPF with prostate cancer and high-grade prostate cancer were 0.58 (95% CI 0.54-0.62) and 0.59 (95% CI 0.55-0.64), respectively.

CONCLUSION

The amount of PPF can be estimated with TRUS and is a predictor of prostate cancer and high-grade prostate cancer at biopsy. To our knowledge, this study is the first to investigate PPF quantity in patients without prior prostate cancer diagnosis.