Periprostatic adipose tissue-derived adipokine profile in prostate cancer patients reveals two distinct molecular phenotypes linked to obesity-related comorbidities: multifaceted role of lipocalin-2

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 is associated with more aggressive prostate cancer (PCa), with visceral obesity conferring an even higher risk than generalized obesity. However, the mechanism by which obesity fuels PCa progression remains unclear. As an active endocrine organ, adipose tissue contributes to metabolic regulation, and current data suggest that the periprostatic adipose (PPA) tissue from obese PCa patients promotes a tumor permissive microenvironment. We hypothesized that altered lipid metabolism in the PPA tissue may be one mechanism for this activity. In this pilot study, we used MR spectroscopy, a technique which could be readily utilized in vivo to obtain the FA signature of tissues non-invasively, to compare the fatty acid (FA) profiles of PPA tissue and subcutaneous adipose (SQA) tissue taken from PCa patients (n=12). The FA profiles of fat biopsies were obtained from proton MR spectra as follows: PRESS localized spectra were acquired from 8μL voxels in fresh tissue on a 600MHz Bruker Avance spectrometer using recycle time TR 4000ms, echo delay time TE 7.5ms, spectral width 8000Hz, number of complex points 16k, and 256 averages. The various functional groups in FA were identified by peaks appearing at characteristic frequencies (chemical shifts) in the proton spectrum. Peak integrals of FA functional groups were measured from which the fractions of saturated (fS), mono-unsaturated (fM), and poly-unsaturated fatty acids (fP), as well as the fractions of 16C FA (f16C) and 18C FA (f18C) were calculated using published methods (Ren, et al. J. Lipid Res. 49: 2055, 2008). We found that mono-unsaturated FA fraction (fM ∼0.40) was higher than saturated or poly-unsaturated FA fraction in both PPA and SQA tissues from PCa patients. However, in the PPA, fM > fS > fP, whereas in the SQA tissue, fM > fP ∼ fS. In a parallel study, we examined the PPA tissue from obese (ob/ob) mice which develop prostate hyperplasia (unpublished results). In these samples, the mono-unsaturated fatty acids were the predominant FA (fM 0.44) while in wildtype control mice polyunsaturated fatty acids (fP 0.47) were the major FA in the PPA tissue. In the human tissues, while f18C > f16C in both adipose depots, the ratio (f16C/ f18C) was significantly higher in PPA (0.59) than in SQA (0.14). This increased abundance of shorter chain length FA (f16C) suggests that PPA may be metabolically more active than SQA in PCa patients, as shorter chain length FA are mobilized at a higher rate. These data support the potential utility of MR spectroscopy to establish FA profiles of PPA tissue, and in ongoing studies we will test tissues from obese PCa patients and normal controls to determine if differences can be exploited to provide additional diagnostic or prognostic information using this noninvasive technique. (Supported by an award from the Prostate Cancer Foundation, a pilot grant award from NorthShore University HealthSystem, and NIH S10 RR13880) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-321. doi:10.1158/1538-7445.AM2011-LB-321

The prostate is surrounded by periprostatic adipose tissue (PPAT), the thickness of which has been associated with more aggressive prostate cancer (PCa). There are limited data regarding the functional characteristics of PPAT, how it compares to subcutaneous adipose tissue (SAT), and whether in a setting of localized PCa, these traits are altered by obesity or disease aggressiveness. PPAT and SAT were collected from 60 men (age: 42–78 years, BMI: 21.3–35.6 kg/m2) undergoing total prostatectomy for PCa. Compared to SAT, adipocytes in PPAT were smaller, had the same basal rates of fatty acid release (lipolysis) yet released less polyunsaturated fatty acid species, and were more sensitive to isoproterenol-stimulated lipolysis. Basal lipolysis of PPAT was increased in men diagnosed with less aggressive PCa (Gleason score (GS) ≤ 3 + 4) compared to men with more aggressive PCa (GS ≥ 4 + 3) but no other measured adipocyte parameters related to PCa aggressiveness. Likewise, there was no difference in PPAT lipid biology between lean and obese men. In conclusion, lipid biological features of PPAT do differ from SAT; however, we did not observe any meaningful difference in ex vivo PPAT biology that is associated with PCa aggressiveness or obesity. As such, our findings do not support a relationship between altered PCa behavior in obese men and the metabolic reprogramming of PPAT.

Prostate cancer (PCA) is a leading cause of cancer death in men. Underlying immunosuppressive mechanisms in benign prostate hyperplasia (BPH) and PCA patients are not fully clarified. We analyzed homeostatic proliferation of CD8+ T cells upon stimulation with common receptor γ chain IL-2, IL-7 and IL-15 cytokines in PCA as compared to BPH patients. CD8+ T cells exhaustion was assessed by evaluating Programmed Death-1 (PD-1) receptor and its ligand PD-L1 expression in PBMC and tissue infiltrating CD8+ T cells from PCA and BPH patients. 57 BPH and 76 PCA patients were enrolled. Gene expression was quantified by Real-Time PCR. T cell proliferation was evaluated by CFSE dilution. CD132, CD122, PD-1 and PD-Ll expression were assessed by flow cytometry. IL-2, IL-7 and IL-15 gene expression were quantified in PCA (n=57) and BPH (n=32) tissues. IL-7 and IL-15 gene expression were significantly increased in PCA tissues as compared to BPH (p=0.024; p=0.031). No significant differences were observed for IL-2 gene expression. CD8+ cells from BPH (n=17) and PCA (n=21) patients showed a significantly decreased responsiveness to IL-7 and IL-15 (p=0.021; p=0.015) as compared to healthy donors (n=9). Response to IL-2 was similar. A trend towards a lower response to IL-15 in PCA as compared to BPH patients was detectable. Percentage of CD8+ T cells expressing the common γ chain (CD132) of homeostatic cytokines receptor is significantly decreased in PCA (n=13) and BPH (n=16) patients as compared to healthy donors (n=8) (p= 0.024; p<0.001). Percentage of CD8+ T cells expressing the common β chain (CD122) is significantly decreased in PCA patients as compared to healthy donors (p=0.035). No significant differences were noticed for the expression of the α chain of homeostatic cytokine receptor. Urged by these findings, we addressed the expression of PD-1 and its ligand in CD8+ T cells from BPH and PCA patients. In BPH (n=7) and PCA (n=7), %CD8+PD-1+ and %CD8+PD-L1+ T cells are increasing upon culture with homeostatic cytokines. In freshly isolated CD8+ cells, a highly significant increase in the %CD8+PD-1+ cells was observed in PCA (n=32) and BPH (n=22) as compared to healthy donors (p<0.001; p<0.001). In contrast, PD-L1 expression in CD8+ cells was similar in BPH and PCA patients and in healthy donors. A large majority of CD8+ cells infiltrating BPH or PCA tissues (83±22% for BPH, n=9; 88±17% for PCA, n=7) were PD-1+, whereas PD-L1 was expressed in 51±43% and 37±39% of infiltrating CD8+ T cells in BPH and PCA, respectively. Taken together these data indicate that both BPH and PCA patients display a decreased responsiveness to IL-7 and IL-15 homeostatic cytokines. Interestingly, high percentages of peripheral blood CD8+ T cells express PD-1 in BPH and PCA patients. Notably, PD-1 and its ligand are highly expressed in tissue infiltrating CD8+ T cells in BPH and PCA patients, thus raising the issue of the role of T cells exhaustion in PCA. 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 4782.

BackgroundAdipose tissue has gained attention due to its potential paracrine role. Periprostatic adipose tissue surrounds the prostate and the prostatic urethra, and it is an essential player in prostate cancer progression. Since obesity is directly related to human tumor progression, and adipose tissue depots are one of the significant components of the tumor microenvironment, the molecular mediators of the communication between adipocytes and epithelial cells are in the spotlight. Although periprostatic white adipose tissue contributes to prostate cancer progression, brown adipose tissue (BAT), which has beneficial effects in metabolic pathologies, has been scarcely investigated concerning cancer progression. Given that adipose tissue is a target of androgen signaling, the actual role of androgen removal on the periprostatic adipose tissue was the aim of this work.MethodsSurgical castration of the transgenic adenocarcinoma of the mouse prostate (TRAMP) was employed. By histology examination and software analysis, WAT and BAT tissue was quantified. 3T3-like adipocytes were used to study the role of Casodex® in modifying adipocyte differentiation and to investigate the function of the secretome of adipocytes on the proliferation of androgen-dependent and independent prostate cancer cells. Finally, the role of cell communication was assayed by TRAMP-C1 xenograft implanted in the presence of 3T3-like adipocytes.ResultsAndrogen removal increases brown/beige adipose tissue in the fat immediately surrounding the prostate glands of TRAMP mice, concomitant with an adjustment of the metabolism. Castration increases body temperature, respiratory exchange rate, and energy expenditure. Also, in vitro, it is described that blocking androgen signaling by Casodex® increases the uncoupling protein 1 (UCP1) marker in 3T3-like adipocytes. Finally, the effect of brown/beige adipocyte secretome was studied on the proliferation of prostate cancer cells in vivo and in vitro. The secretome of brown/beige adipocytes reduces the proliferation of prostate cancer cells mediated partly by the secretion of extracellular vesicles.ConclusionsConsequently, we concluded that hampering androgen signaling plays a crucial role in the browning of the periprostatic adipose tissue. Also, the presence of brown adipocytes exhibits the opposite effect to that of white adipocytes in vitro regulating processes that govern the mechanisms of cell proliferation of prostate cancer cells. And finally, promoting the browning of adipose tissue in the periprostatic adipose tissue might be a way to handle prostate cancer cell progression.EECkevEGf-HMwkJP3j4bZsVideo

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

Background: While obesity is associated with increased risk of aggressive prostate cancer, mechanisms remain unclear. Periprostatic adipose tissue (PPAT), a visceral fat depot surrounding the prostate, may influence tumourigenesis via inflammatory and metabolic pathways. Prior research is limited to small studies of men with prostate cancer. This study characterises PPAT in a large, longitudinal cohort of prostate cancer-free men and examines its relationship with anthropometric, metabolic, demographic and lifestyle factors. Methods: Using magnetic resonance images (MRIs) from 27,748 male UK Biobank participants, an nnUNet autosegmentation model was used to quantify the volume of PPAT, defined as adipose tissue surrounding the prostate and anterior to the rectal wall. Spearman and partial correlation assessed the relationship of PPAT volume with other adiposity and anthropometric measures, and with markers of systemic metabolic health. Age and race-adjusted linear regression examined associations of log-transformed, standardised measures of PPAT volume, and of other adiposity measures, with demographic and lifestyle characteristics. Beta coefficients were exponentiated to estimate percentage differences. Results: Men had a median PPAT volume of 14ml (interquartile range (IQR), 8-23ml) and median abdominal visceral adipose tissue (VAT) volume of 4.7L (IQR 3.2-6.3L). PPAT volume correlated more strongly with VAT volume (r=0.61) than with other anthropometric measures, including body mass index (BMI; r=0.47) or waist circumference (r=0.48). Correlations of PPAT with systemic measures of metabolic health were weak (all r<0.3) and attenuated (all r<0.1) after adjusting for VAT using partial correlation. While VAT volume was 19% higher in older (65+ years) relative to younger men (<45 years), PPAT volume more than doubled over this age range (+104%). By contrast, BMI was lower in older vs younger men (-19%). While black men had higher BMI relative to white men (+20%), they had less VAT (-56%) and PPAT (-31%). Associations of PPAT volume with lifestyle characteristics followed similar patterns as for VAT, although slightly less pronounced. Men completing higher level education vs high school only had less PPAT (-14%) and less VAT (-23%). Relative to sedentary men, those reporting physical activity equating to an hour moderate intensity or 30 minutes high intensity activity per day had less PPAT (-20%) and less VAT (-28%). Men with benign prostatic hyperplasia (BPH) had higher PPAT (+9%) but no significant difference in VAT volume. Conclusions: In the largest study to date in prostate cancer-free men, we find that PPAT is closely associated with visceral obesity and more strongly associated with aging than other adiposity measures. Weak correlations of PPAT with measures of systemic metabolic health imply any influence on prostate growth and tumorigenesis may be through local effects. Associations of PPAT volume with lifestyle characteristics may support its modifiable nature, potentially through interventions to reduce visceral adiposity. Citation Format: Jade Dorrian, Emma H. Allott, Ryan O’Keeffe, Angela O'Neill, Sarah Winter, Joshua Atkins, Mahboubeh Parsaeian, Karl Smith-Byrne, Amy Dawes, Vilmundur Guðnason, Ruth Travis, Tom Gaunt, Michelle Leech. Characterization of periprostatic adipose tissue in 27,748 Men: Links to visceral fat, aging, and factors relevant to prostate cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Innovations in Prostate Cancer Research and Treatment; 2026 Jan 20-22; Philadelphia PA. Philadelphia (PA): AACR; Cancer Res 2026;86(2_Suppl):Abstract nr B015.

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. 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. 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. 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.

Extraprostatic Extension into Periprostatic Fat is a More Important Determinant of Prostate Cancer Recurrence than an Invasive Phenotype

Epigenome-wide DNA methylation and transcriptome profiling of localized and locally advanced prostate cancer: Uncovering new molecular markers

The aim of this study was to determine fatty acid composition in periprostatic adipose tissue (PPAT) of patients undergoing surgery for either prostatic cancer or benign prostatic hyperplasia (BPH). PPAT were obtained from 12 patients undergoing radical prostatectomy for clinically localized prostate tumors (TPPAT, age range 55-70 years) and 11 patients undergoing adenomectomy for BPH (BPPAT, age range 57-79 years). Fatty acid methyl esters of total lipids of PPAT were processed and then analyzed by gas chromatography-mass spectrometry. Quantitation was performed by comparing the percentage area of each FAME peak on the chromatogram with that of the internal standard of known weight, and expressed as percentage of total fatty acids. There were differences in fatty acid content of PPAT, with higher levels of palmitic acid (16:0; P = 0.036) and dihomo-gammalinolenic acid (20:3 n-6; P = 0.020) and lower levels of arachidonic acid (20:4 n-6; P = 0.030) in prostate cancer PPAT, along with a higher 20:4/20:3 (P = 0.001) and lower 20:3/18:2 (P = 0.027) fatty acid ratio in benign prostate hyperplasia PPAT. To the best of our knowledge, this study represents the first attempt at comparing periprostatic fat pad lipid composition in different prostate pathologies. Fatty acid analysis and lipidomics may be important tools to further understand events that occur in tumor microenvironment during prostate cancer disease.

Periprostatic Adipose Tissue as a Modulator of Prostate Cancer Aggressiveness

Background/Aims: Adipose microenvironment is involved in signaling pathways that influence prostate cancer (PCa) progression. However, the role of human periprostatic adipose tissue (PPAT) from patients with benign prostatic hyperplasia (BPH) has not been studied and compared to that of PPAT from PCa patients. The aim of this paper was to investigate the influence of factors derived from both PPATs on the behavior of androgen-dependent and castration resistant PCa cells. Methods: PPAT conditioned media (CM) were obtained from tissue samples from patients with clinically primary PCa (TPPAT) or BPH (BPPAT). Cell adhesion, proliferation, migration and metalloproteinase expression were evaluated following exposure of LNCaP (androgen dependent) and PC3 (androgen independent) prostate cancer cell lines to BPPAT or TPPAT CM. Results: Proliferation or motility of LNCaP or PC3 cells were not significantly affected by TPPAT or BPPAT CM. The number of LNCaP but not PC3 cells attached to components of TPPAT CM significantly decreased compared to cells attached to BPPAT CM. PPAT produced and released pro-MMP-9. Zymograms demonstrated that TPPAT CM induced a significant increase in pro-MMP-9 activity compared to BPPAT CM in LNCaP cells but not in PC3 cells. Conclusions: We conclude that TPPAT released factors, such as pro-MMP-9, could induce the invasive capacity of LNCaP cells and speculate that PPAT derived factors could, in the early stages of prostate cancer, modulate disease progression.

Periprostatic adipose tissue (PPAT) directs tumour behaviour. Microenvironment secretome provides information related to its biology. This study was performed to identify secreted proteins by PPAT, from both prostate cancer and benign prostate hyperplasia (BPH) patients. Liquid chromatography-mass spectrometry-based proteomic analysis was performed in PPAT-conditioned media (CM) from patients with prostate cancer (CMs-T) (stage T3: CM-T3, stage T2: CM-T2) or benign disease (CM-BPH). The highest number and diversity of proteins was identified in CM-T3. Locomotion was the biological process mainly associated to CMs-T and reproduction to CM-T3. Immune responses were enriched in CMs-T. Extracellular matrix and structural proteins were associated to CMs-T. CM-T3 was enriched in proteins with catalytic activity and CM-T2 in proteins with defense/immunity activity. Metabolism and energy pathways were enriched in CM-T3 and those with immune system functions in CMs-T. Transport proteins were enriched in CM-T2 and CM-BPH. Proteins and pathways reported in this study could be useful to distinguish stages of disease and may become targets for novel therapies.

Background: The prostate gland is surrounded by periprostatic adipose tissue (PPAT) that can release mediators that interfere in prostate function. In this study, we examined the effect of periprostatic adipose tissue supernatant obtained from obese mice on prostate reactivity in vitro and on the viability of human prostatic epithelial cell lines. Methods: Male C57BL/6 mice were fed a standard or high-fat diet after which PPAT was isolated, incubated in Krebs-Henseleit solution for 30min (without prostate) or 60min (with prostate), and the supernatant was then collected and screened for biological activity. Total nitrate and nitrite (NOx-) and adenosine were quantified, and the supernatant was then collected and screened for biological activity. NOx- and adenosine were quantified. Concentration-response curves to phenylephrine (PE) were obtained in prostatic tissue from lean and obese mice incubated with or without periprostatic adipose tissue. In some experiments, periprostatic adipose tissue was co-incubated with inhibitors of the nitric oxide (NO)-cyclic guanosine monophosphate pathway (L-NAME, 1400W, ODQ), adenylate cyclase (SQ22536) or with adenosine A2A (ZM241385), and A2B (MRS1754) receptor antagonists. PNT1-A (normal) and BPH-1 (hyperplasic) human epithelial cells were cultured and incubated with supernatant from periprostatic adipose tissue for 24, 48, or 72h in the absence or presence of these inhibitors/antagonists, after which cell viability and proliferation were assessed. Results: The levels of NOx- and adenosine were significantly higher in the periprostatic adipose tissue supernatant (30min, without prostate) when compared to the vehicle. A trend toward an increase in the levels of NOX was observed after 60min. PPAT supernatant from obese mice significantly reduced the PE-induced contractions only in prostate from obese mice. The co-incubation of periprostatic adipose tissue with L-NAME, 1400W, ODQ, or ZM241385 attenuated the anticontractile activity of the periprostatic adipose tissue supernatant. Incubation with the supernatant of periprostatic adipose tissue from obese mice significantly increased the viability of PNT1-A cells and attenuated expression of the apoptosis marker protein caspase-3 when compared to cells incubated with periprostatic adipose tissue from lean mice. Hyperplastic cells (BPH-1) incubated with periprostatic adipose tissue from obese mice showed greater proliferation after 24h, 48h, and 72h compared to cells incubated with culture medium alone. BPH-1 cell proliferation in the presence of PPAT supernatant was attenuated by NO-signaling pathway inhibitors and by adenosine receptor antagonists after 72h. Conclusion: NO and adenosine are involved in the anticontractile and pro-proliferative activities of periprostatic adipose tissue supernatant from obese mice. More studies are needed to determine whether the blockade of NO and/or adenosine derived from periprostatic adipose tissue can improve prostate function.