Key participants of the tumor microenvironment of the prostate: an approach of the structural dynamic of cellular elements and extracellular matrix components during epithelial-stromal transition

Reactive Stroma and Acinar Morphology in Prostate Cancer: Implications for Progression and Prognostic Assessment

INTRODUCTION

Prostate cancer (PC) remains a significant global health concern, with prognostic assessments largely reliant on the Gleason Classification System. While it has proven effective, subjectivity in interpretation persists, prompting the need for complementary approaches. Reactive stroma (RS) has emerged as a potential candidate for enhancing PC characterization, as it reflects intricate interactions among stromal, epithelial, and extracellular matrix components. To shed light on this, we conducted a comprehensive study.

METHODS

Two expert pathologists independently analyzed consecutive prostate biopsies (n = 120 patients), categorized into four groups based on Gleason scores. Four acinar patterns were described, denoted as A, B, C, and D. Our study uncovered a noteworthy presence of RS, predominantly within poorly differentiated tumors. Stromogenic tumors, characterized by high RS content, were particularly associated with Gleason scores of 4 + 3 and ≥ 8. Intriguingly, acinar patterns, including the distinctive B and D patterns, exhibited strong correlations with stromogenic tumors. Incorporating quantitative imaging techniques (Second Harmonic Generation and Two-Photon Excitation Fluorescence Microscopy), we examined collagen fiber density within the stroma.

RESULTS

Our analysis revealed a direct relationship between RS intensity and collagen fiber counts, particularly prominent in patterns B and D. These findings suggest that the stromal reaction in PC is closely linked to acinar morphology and collagen deposition. Moreover, rudimentary microacini at the tumor periphery, associated with intense RS and patterns B and D, may signify an unfavorable prognosis.

CONCLUSION

Our study highlights the potential of RS as an additional prognostic factor in PC. It underscores the intricate interplay between acinar patterns, RS intensity, and collagen fiber density, providing valuable insights for future prognostic assessments and therapeutic strategies. Further exploration of these relationships is essential for a comprehensive understanding of PC progression and management.

Nanomechanical-based classification of prostate tumor using atomic force microscopy

BACKGROUND

The loss of mechanical homeostasis between tumor cells and microenvironment is an important factor in tumor metastasis. In the process, mechanical forces affect cell proliferation, differentiation, migration and tissue development.

AIMS

Using high spatial resolution of Atomic force microscopy (AFM) technology, our study provides the direct measurement of the nanomechanical properties of prostate cancer clinical tissue specimens.

MATERIALS AND METHODS

AFM was used to determine the biomechanical properties of prostate tissue with different grade scores. K-means clustering method and fuzzy C-means were used to distinguish the cellular component in prostate tissue from non-cellular component based on their viscoelasticity. Futhermore, AFM measurements in vitro cells, including metastatic prostate cells (PC-3) and normal human prostate cells (PZ-HPV-7) were carried out.

RESULTS

The Young's modulus was decreased in prostate cancer progression, and the elasticity of cellular component in prostate cancer tissue was smaller than that of normal prostate tissue. PC-3 cells were softer than PZ-HPV-7 cells. Further mechanism investigation showed that the difference in modulus between cancerous and normal prostate tissue may be associated with a greater actin cytoskeleton distribution inside the cancer cells.

CONCLUSION

The results suggests that the nanomechanical properties can classify the prostate tumor, which could be used as an index for the identification and classification of cancer at cellular level.

Long exposure to a mixture of endocrine disruptors prediposes the ventral prostate of rats to preneoplastic lesions

Endocrine disruptors (ED) are compounds dispersed in the environment that modify hormone biosynthesis, affecting hormone-dependent organs such as the prostate. Studies have only focused on evaluating the effects of ED alone or in small groups and short intervals and have not adequately portrayed human exposure. Therefore, we characterized the prostate histoarchitecture of rats exposed to an ED mixture (ED Mix) mimicking human exposure. Pregnant females of the Sprague-Dawley strain were randomly distributed into two experimental groups: Control group (vehicle: corn oil, by gavage) and ED Mix group: received 32.11 mg/kg/day of the ED mixture diluted in corn oil (2 ml/kg), by gavage, from gestational day 7 (DG7) to post-natal day 21 (DPN21). After weaning at DPN22, the male pups continued to receive the complete DE mixture until they were 220 days old when they were euthanized. The ED Mix decreased the epithelial compartment, increased the fractal dimension, and decreased glandular dilation. In addition, low-grade prostatic intraepithelial neoplasia was observed in addition to regions of epithelial atrophy in the group exposed to the ED Mix. Exposure to the mixture decreased both types I and III collagen area in the stroma. We concluded that the ED Mix was able to cause alterations in the prostatic histoarchitecture and induce the appearance of preneoplastic lesions.

2,4-dichlorophenoxyacetic acid (2,4-D) exposure during postnatal development alters the effects of western diet on mouse prostate

Western diet (WD), abundant in saturated fats and simple carbohydrates, has been associated with the development of prostate diseases. In addition, 2,4-dichlorophenoxyacetic acid (2,4-D), an herbicide used in agricultural and non-agricultural settings, may interfere with the endocrine system impacting reproductive health. The association of both factors is something common in everyday life, however, there are no relevant studies associating them as possible modulators of prostatic diseases. This study evaluated the action of the herbicide 2,4-D on the postnatal development of the prostate in mice fed with WD. Male C57Bl/6J mice received simultaneously a WD and 2,4-D at doses of 0.02, 2.0, or 20.0 mg/kg b.w./day for 6 months. The prolongated WD intake induced obesity and glucose intolerance, increasing body weight and fat. WD induced morphological changes and increased PCNA-positive epithelial cells in prostate. Additionally, the WD increased gene expression of AR, antioxidant targets, inflammation-related cytokines, cell repair and turnover, and targets related to methylation and miRNAs biosynthesis compared to the counterpart (basal diet). 2,4-D (0.02 and 2.0) changed prostate morphology and gene expression evoked by WD. In contrast, the WD group exposed to 20 mg/kg of 2,4-D reduced feed intake and body weight, and increased expression of androgen receptor and genes related to cell repair and DNA methylation compared to the negative control. Our results showed that 2,4-D was able to modulate the effects caused by WD, mainly at lower doses. However, further studies are needed to elucidate the mechanisms of 2,4-D on the obesogenic environment caused by the WD.

The impacts of exposure to bisphenol A in the adult female prostate Meriones unguiculatus

The female prostate is associated with the urogenital system and presents homology in morphological terms with the male prostate. Due to its responsiveness to endogenous hormones, this gland is under a constant risk of developing prostatic pathologies and neoplasia when exposed to certain exogenous compounds. Bisphenol A (BPA) is an endocrine disruptor found in different plastic and resin products. Studies have emphasized the effects of perinatal exposure to this compound on different hormone-responsive organs. However, there have been few studies highlighting the influence on female prostate morphology of perinatal exposure to BPA. The objective of this study was to describe the histopathological alterations caused by perinatal exposure to BPA (50 µg/kg) and 17-β estradiol (E2) (35 µg/kg) in the prostate of adult female gerbils. The results showed that E2 and BPA induced proliferative lesions in the female prostate and acted along similar pathways by modulating steroid receptors in the epithelium. BPA was also found to be a pro-inflammatory and pro-angiogenic agent. The impacts of both agents were marked in the prostatic stroma. An increase in the thickness of the smooth muscle layer and a decrease in AR expression were observed, but no alterations in the expression of ERα and ERβ, leading to estrogenic sensitivity of the prostate. However, a peculiar response of the female prostate was to diminish the collagen frequency under BPA exposure correlated to smooth muscle layer. These data therefore indicate the development of features related to estrogenic and non-estrogenic tissue repercussions by BPA perinatally exposure in gerbil female prostate.

Collagen-Specific Molecular Magnetic Resonance Imaging of Prostate Cancer

Constant interactions between tumor cells and the extracellular matrix (ECM) influence the progression of prostate cancer (PCa). One of the key components of the ECM are collagen fibers, since they are responsible for the tissue stiffness, growth, adhesion, proliferation, migration, invasion/metastasis, cell signaling, and immune recruitment of tumor cells. To explore this molecular marker in the content of PCa, we investigated two different tumor volumes (500 mm3 and 1000 mm3) of a xenograft mouse model of PCa with molecular magnetic resonance imaging (MRI) using a collagen-specific probe. For in vivo MRI evaluation, T1-weighted sequences before and after probe administration were analyzed. No significant signal difference between the two tumor volumes could be found. However, we detected a significant difference between the signal intensity of the peripheral tumor area and the central area of the tumor, at both 500 mm3 (p < 0.01, n = 16) and at 1000 mm3 (p < 0.01, n = 16). The results of our histologic analyses confirmed the in vivo studies: There was no significant difference in the amount of collagen between the two tumor volumes (p > 0.05), but within the tumor, higher collagen expression was observed in the peripheral area compared with the central area of the tumor. Laser ablation with inductively coupled plasma mass spectrometry further confirmed these results. The 1000 mm3 tumors contained 2.8 ± 1.0% collagen and the 500 mm3 tumors contained 3.2 ± 1.2% (n = 16). There was a strong correlation between the in vivo MRI data and the ex vivo histological data (y = −0.068x + 1.1; R2 = 0.74) (n = 16). The results of elemental analysis by inductively coupled plasma mass spectrometry supported the MRI data (y = 3.82x + 0.56; R2 = 0.79; n = 7). MRI with the collagen-specific probe in PCa enables differentiation between different tumor areas. This may help to differentiate tumor from healthy tissue, potentially identifying tumor areas with a specific tumor biology.

Fibronectin Modulates the Expression of miRNAs in Prostate Cancer Cell Lines

Prostate cancer (PCa) is a significant cause of cancer-related deaths among men and companion animals, such as dogs. However, despite its high mortality and incidence rates, the molecular mechanisms underlying this disease remain to be fully elucidated. Among the many factors involved in prostate carcinogenesis, the extracellular matrix (ECM) plays a crucial role. This ECM in the prostate is composed mainly of collagen fibers, reticular fibers, elastic fibers, proteoglycans and glycoproteins, such as fibronectin. Fibronectin is a glycoprotein whose dysregulation has been implicated in the development of multiple types of cancer, and it has been associated with cell migration, invasion, and metastasis. Furthermore, our research group has previously shown that fibronectin induces transcriptional changes by modulating the expression of protein coding genes in LNCaP cells. However, potential changes at the post-transcriptional level are still not well understood. This study investigated the impact of exposure to fibronectin on the expression of a key class of regulatory RNAs, the microRNAs (miRNAs), in prostate cancer cell lines LNCaP and PC-3. Five mammalian miRNAs (miR-21, miR-29b, miR-125b, miR-221, and miR-222) were differentially expressed after fibronectin exposure in prostate cell lines. The expression profile of hundreds of mRNAs predicted to be targeted by these miRNAs was analyzed using publicly available RNA-Sequencing data (GSE64025, GSE68645, GSE29155). Also, protein-protein interaction networks and enrichment analysis were performed to gain insights into miRNA biological functions. Altogether, these functional analyzes revealed that fibronectin exposure impacts the expression of miRNAs potentially involved in PCa causing changes in critical signaling pathways such as PI3K-AKT, and response to cell division, death, proliferation, and migration. The relationship here demonstrated between fibronectin exposure and altered miRNA expression improves the comprehension of PCa in both men and other animals, such as dogs, which naturally develop prostate cancer.

The Extracellular Matrix Stiffening: A Trigger of Prostate Cancer Progression and Castration Resistance?

Despite advancements made in diagnosis and treatment, prostate cancer remains the second most diagnosed cancer among men worldwide in 2020, and the first in North America and Europe. Patients with localized disease usually respond well to first-line treatments, however, up to 30% develop castration-resistant prostate cancer (CRPC), which is often metastatic, making this stage of the disease incurable and ultimately fatal. Over the last years, interest has grown into the extracellular matrix (ECM) stiffening as an important mediator of diseases, including cancers. While this process is increasingly well-characterized in breast cancer, a similar in-depth look at ECM stiffening remains lacking for prostate cancer. In this review, we scrutinize the current state of literature regarding ECM stiffening in prostate cancer and its potential association with disease progression and castration resistance.

Prenatal and pubertal exposure to 17α-ethinylestradiol cause morphological changes in the prostate of old gerbils

This study evaluated such as exposure to ethinylestradiol during the prenatal (18th-22nd day) and pubertal (42nd-49th day) periods acts on the male ventral prostate and female prostate of 12-month old gerbils. We performed the analysis to serum hormone levels for estradiol and testosterone. The prostates were submitted to morphometric and immunohistochemical analyses. Exposure to ethinylestradiol during these developmental periods decreased the testosterone serum levels in males and increased the estradiol serum levels in females. Morphologically, prostate intraepithelial neoplasia and disorders in the arrangement of the fibrous components were observed in the prostate glands of both sexes of gerbil exposed to ethinylestradiol during development periods. In the male prostate, the ethinylestradiol promoted decreased in the frequency of positive epithelial cell for androgen receptor (AR) and increased the frequency of positive stromal cell for estrogen receptor α. However, in the female prostate, this synthetic estrogen caused AR upregulation and increased cell proliferation. This study shows that the exposure to ethinylestradiol during development phases alters the morphology and the hormonal signaling in the male and female prostates of old gerbils, confirming the action of ethinylestradiol as endocrine disruptor.

Mass Spectrometry Imaging of Fibroblasts: Promise and Challenge

INTRODUCTION

Fibroblasts maintain tissue and organ homeostasis through output of extracellular matrix that affects nearby cell signaling within the stroma. Altered fibroblast signaling contributes to many disease states and extracellular matrix secreted by fibroblasts has been used to stratify patient by outcome, recurrence, and therapeutic resistance. Recent advances in imaging mass spectrometry allow access to single cell fibroblasts and their ECM niche within clinically relevant tissue samples.

AREAS COVERED

We review biological and technical challenges as well as new solutions to proteomic access of fibroblast expression within the complex tissue microenvironment. Review topics cover conventional proteomic methods for single fibroblast analysis and current approaches to accessing single fibroblast proteomes by imaging mass spectrometry approaches. Strategies to target and evaluate the single cell stroma proteome on the basis of cell signaling are presented.

EXPERT OPINION

The promise of defining proteomic signatures from fibroblasts and their extracellular matrix niches is the discovery of new disease markers and the ability to refine therapeutic treatments. Several imaging mass spectrometry approaches exist to define the fibroblast in the setting of pathological changes from clinically acquired samples. Continued technology advances are needed to access and understand the stromal proteome and apply testing to the clinic.

Zonal regulation of collagen-type proteins and posttranslational modifications in prostatic benign and cancer tissues by imaging mass spectrometry

BACKGROUND

The emergence of reactive stroma is a hallmark of prostate cancer (PCa) progression and a potential source for prognostic and diagnostic markers of PCa. Collagen is a main component of reactive stroma and changes systematically and quantitatively to reflect the course of PCa, yet has remained undefined due to a lack of tools that can define collagen protein structure. Here we use a novel collagen-targeting proteomics approach to investigate zonal regulation of collagen-type proteins in PCa prostatectomies.

METHODS

Prostatectomies from nine patients were divided into zones containing 0%, 5%, 20%, 70% to 80% glandular tissue and 0%, 5%, 25%, 70% by mass of PCa tumor following the McNeal model. Tissue sections from zones were graded by a pathologist for Gleason score, percent tumor present, percent prostatic intraepithelial neoplasia and/or inflammation (INF). High-resolution accurate mass collagen targeting proteomics was done on a select subset of tissue sections from patient-matched tumor or nontumor zones. Imaging mass spectrometry was used to investigate collagen-type regulation corresponding to pathologist-defined regions.

RESULTS

Complex collagen proteomes were detected from all zones. COL17A and COL27A increased in zones of INF compared with zones with tumor present. COL3A1, COL4A5, and COL8A2 consistently increased in zones with tumor content, independent of tumor size. Collagen hydroxylation of proline (HYP) was altered in tumor zones compared with zones with INF and no tumor. COL3A1 and COL5A1 showed significant changes in HYP peptide ratios within tumor compared with zones of INF (2.59 ± 0.29, P value: .015; 3.75 ± 0.96 P value .036, respectively). By imaging mass spectrometry COL3A1 showed defined localization and regulation to tumor pathology. COL1A1 and COL1A2 showed gradient regulation corresponding to PCa pathology across zones. Pathologist-defined tumor regions showed significant increases in COL1A1 HYP modifications compared with COL1A2 HYP modifications. Certain COL1A1 and COL1A2 peptides could discriminate between pathologist-defined tumor and inflammatory regions.

CONCLUSIONS

Site-specific posttranslational regulation of collagen structure by proline hydroxylation may be involved in reactive stroma associated with PCa progression. Translational and posttranslational regulation of collagen protein structure has potential for new markers to understand PCa progression and outcomes.

Distribution of spleen connective tissue fibers in diabetic and vitamin C treated diabetic rats

We investigated the distribution of connective tissue fibers in diabetic and vitamin C treated diabetic rat spleen. Rats were divided into three groups: group A, control; group B, diabetic; group C, vitamin C treated diabetic. Diabetes was induced by streptozotocin. Vitamin C was administered intragastrically for 21 days. Spleen tissues were examined by light microscopy after staining with Masson's trichrome, Gomori silver impregnation and van Gieson. In group B, we found accumulation of collagen fibers in the trabeculae, in the capsule and around the central artery and splenic sinusoids. Splenic cord thickening due to fibrosis was observed. Reticular fibers accumulated principally in the white and red pulps of the spleen and focal reticular fiber thickening was observed in the dense fiber areas. Partial elastic fiber rupture was observed among the fibers of the elastic lamina of the arteries in the hilum. By contrast, the distribution of collagen fibers in group C was similar to group A. Collagen fiber accumulation was decreased in group C compared to group B. We found little reticular fiber thickening in group C and elastic fibers maintained their integrity and were better organized than in group B. Our findings suggest that appropriate doses of vitamin C may exert beneficial effects on the structure of the connective tissue fibers in the diabetic spleen.

Characterization of Collagen Fibers (I, III, IV) and Elastin of Normal and Neoplastic Canine Prostatic Tissues

This study aimed to investigate collagen (Coll-I, III, IV) and elastin in canine normal prostate and prostate cancer (PC) using Picrosirius red (PSR) and Immunohistochemical (IHC) analysis. Eight normal prostates and 10 PC from formalin-fixed, paraffin-embedded samples were used. Collagen fibers area was analyzed with ImageJ software. The distribution of Coll-I and Coll-III was approximately 80% around prostatic ducts and acini, 15% among smooth muscle, and 5% surrounding blood vessels, in both normal prostate and PC. There was a higher median area of Coll-III in PC when compared to normal prostatic tissue (p = 0.001 for PSR and p = 0.05 for IHC). Immunostaining for Coll-IV was observed in the basal membrane of prostate acini, smooth muscle, blood vessels, and nerve fibers of normal and PC samples. Although there was no difference in Coll-IV area between normal tissue and PC, tumors with Gleason score 10 showed absence of Coll-IV, when compared to scores 6 and 8 (p = 0.0095). Elastic fibers were found in the septa dividing the lobules and around the prostatic acini of normal samples and were statistically higher in PC compared to normal tissue (p = 0.00229). Investigation of ECM components brings new information and should be correlated with prognosis in future studies.

Do Androgens Modulate the Pathophysiological Pathways of Inflammation? Appraising the Contemporary Evidence

The role of testosterone in the pathophysiology of inflammation is of critical clinical importance; however, no universal mechanism(s) has been advanced to explain the complex and interwoven pathways of androgens in the attenuation of the inflammatory processes. PubMed and EMBASE searches were performed, including the following key words: "testosterone", "androgens", "inflammatory cytokines", "inflammatory biomarkers" with focus on clinical studies as well as basic scientific studies in human and animal models. Significant benefits of testosterone therapy in ameliorating or attenuating the symptoms of several chronic inflammatory diseases were reported. Because anti⁻tumor necrosis factor therapy is the mainstay for the treatment of moderate-to-severe inflammatory bowel disease; including Crohn's disease and ulcerative colitis, and because testosterone therapy in hypogonadal men with chronic inflammatory conditions reduce tumor necrosis factor-alpha (TNF-α), IL-1β, and IL-6, we suggest that testosterone therapy attenuates the inflammatory process and reduces the burden of disease by mechanisms inhibiting inflammatory cytokine expression and function. Mechanistically, androgens regulate the expression and function of inflammatory cytokines, including TNF-α, IL-1β, IL-6, and CRP (C-reactive protein). Here, we suggest that testosterone regulates multiple and overlapping cellular and molecular pathways involving a host of immune cells and biochemical factors that converge to contribute to attenuation of the inflammatory process.

Assessment of Tumor Stiffness With Shear Wave Elastography in a Human Prostate Cancer Xenograft Implantation Model

OBJECTIVES

To investigate the stiffness of human prostate cancer in a xenograft implantation model using shear wave elastography and compare the pathologic features of tumors with varying elasticity.

METHODS

Human prostate cancer DU-145 cells were injected into 24 nude male mice. The mice were divided into 3 groups according to the time of transplantation (6, 8, and 10 weeks). The volume, elasticity, and Young modulus of tumors were recorded by 2-dimensional sonography and shear wave elastography. The tumors were collected for pathologic analyses: hematoxylin-eosin staining, Ponceau S, and aniline staining were used to stain collagen and elastic fibers, and picric acid-sirius red staining was used to indicate type I and III collagen. The area ratios of collagen I/III were calculated. The correlation between the Young modulus of the tumor and area ratio of collagen I/III were evaluated. Immunohistochemistry of vimentin and α-smooth muscle actin was performed.

RESULTS

Nineteen tumors in 3 groups were collected. The volume and mean Young modulus increased with the time of transplantation. There were more collagen fibers in the stiff tumors, and there were significant differences in the area ratios of collagen I/III between groups 1 (mean ± SD, 0.50 ± 0.17) and 3 (1.97 ± 0.56; P < .01). The Young modulus of the tumors showed a very significant correlation with the area ratios of collagen I/III (r = 0.968; P < .05). The expression level of α-smooth muscle actin protein was higher in group 3 than in the other groups, but differences in vimentin expression were barely seen.

CONCLUSIONS

Shear wave elastography is a novel useful technology for showing the elasticity of human prostate cancer xenograft implantation tumors. Collagen fibers, especially collagen type I, play a crucial role in the elasticity in the human prostate cancer xenograft implantation model.

Neonatal exposure to ethinylestradiol increases ventral prostate growth and promotes epithelial hyperplasia and inflammation in adult male gerbils

The aim of this study was to analyse morphologically the ventral prostate of adult Mongolian gerbils exposed to ethinylestradiol (EE) during the first week of postnatal development. Lactating females received daily, by gavage, doses of 10 μg/kg of EE diluted in 100 μl of mineral oil from the 1st to 10th postnatal day of the pups (EE group). In the control group (C), the lactating females received only the vehicle. Upon completing 120 days of age, the male offspring were euthanized and the prostates collected for analyses. We employed morphological, stereological-morphometrical, immunohistochemical and ultrastructural methods. The results showed that the postnatal exposure to EE doubled the prostatic complex weight, increasing the epithelial and stromal compartments, in addition to the secretory activity of the ventral lobe of the prostate. All glands exposed to EE showed strong stromal remodelling, and some foci of epithelial hyperplasia and inflammatory infiltrate in both luminal and epithelial or stromal compartments. Cells positive for anti-AR and anti-PCNA reactions increased into the epithelial and stromal tissues. ERα-positive cells, which are normally found in the stromal compartment of intact prostates, were frequently observed in the prostatic epithelium of treated animals. This study demonstrated that the exposure to EE during postnatal development causes histophysiological alterations in this gland, predisposing to the development of prostatic lesions during life. These results are important for public health, considering that women worldwide have commonly used EE. Moreover, the bioaccumulation of this chemical has increased in different ecosystems.

Structure and Function of a Prostate Cancer Dissemination-Permissive Extracellular Matrix

Purpose: The poor prognosis of metastatic prostate cancer continues to present a major challenge in prostate cancer treatment. The tumor extracellular matrix (ECM) plays an important role in facilitating metastasis. Here, we investigated the structure and function of an ECM that facilitates prostate cancer metastasis by comparing orthotopic tumors that frequently metastasize to poorly metastatic subcutaneous tumors.Experimental Design: Both tumors were derived from a human prostate cancer PC3 cell line engineered to fluoresce under hypoxia. Second harmonic generation (SHG) microscopy was used to characterize collagen 1 (Col1) fiber patterns in the xenografts as well as in human samples. MRI was used to determine albumin-Gd-diethylenetriaminepenta-acetate (alb-GdDTPA) transport through the ECM using a saturation recovery MR method combined with fast T₁ SNAPSHOT-FLASH imaging. Cancer-associated fibroblasts (CAF) were also quantified in these tumors.Results: Significant structural and functional differences were identified in the prometastatic orthotopic tumor ECM compared to the less metastatic subcutaneous tumor ECM. The significantly higher number of CAFs in orthotopic tumors may explain the higher Col1 fiber volumes in these tumors. In vivo, alb-GdDTPA pooling was significantly elevated in metastatic orthotopic tumors, consistent with the increased Col1 fibers.Conclusions: Developing noninvasive MRI indices of macromolecular transport, together with characterization of Col1 fiber patterns and CAFs can assist in stratifying prostate cancers for aggressive treatments or active surveillance. These results highlight the role of CAFs in supporting or creating aggressive cancers, and the importance of depleting CAFs to prevent metastatic dissemination in prostate cancer. Clin Cancer Res; 23(9); 2245-54. ©2016 AACR.

Cannabinoid receptor-2 agonist inhibits macrophage induced EMT in non-small cell lung cancer by downregulation of EGFR pathway

JWH-015, a cannabinoid receptor 2 (CB2) agonist has tumor regressive property in various cancer types. However, the underlying mechanism by which it acts in lung cancer is still unknown. Tumor associated macrophage (TAM) intensity has positive correlation with tumor progression. Also, macrophages recruited at the tumor site promote tumor growth by enhancing epithelial to mesenchymal (EMT) progression. In this study, we analyzed the role of JWH-015 on EMT and macrophage infiltration by regulation of EGFR signaling. JWH-015 inhibited EMT in NSCLC cells A549 and also reversed the mesenchymal nature of CALU-1 cells by downregulation of EGFR signaling targets like ERK and STAT3. Also, in vitro co-culture experiments of A549 with M2 polarized macrophages provided evidence that JWH-015 decreased migratory and invasive abilities which was proved by reduced expression of FAK, VCAM1, and MMP2. Furthermore, it decreased macrophage induced EMT in A549 by attenuating the mesenchymal character by downregulating EGFR and its targets. These results were confirmed in an in vivo subcutaneous syngenic mouse model where JWH-015 blocks tumor growth and also inhibits macrophage recruitment and EMT at the tumor site which was regulated by EGFR pathway. Finally, JWH-015 reduced lung tumor lesions in an in vivo tumorigenicity mouse model. These data confer the impact of this cannabinoid on anti-proliferative and anti-tumorigenic effects, thus enhancing our understanding of its therapeutic efficacy in NSCLC. Our findings open new avenues for cannabinoid receptor CB2 agonist-JWH-015 as a novel and potential therapeutic target based on EGFR downregulation mechanisms in NSCLC. © 2016 Wiley Periodicals, Inc.

Deep sequencing of small RNA libraries from human prostate epithelial and stromal cells reveal distinct pattern of microRNAs primarily predicted to target growth factors

Complex epithelial and stromal cell interactions are required during the development and progression of prostate cancer. Regulatory small non-coding microRNAs (miRNAs) participate in the spatiotemporal regulation of messenger RNA (mRNA) and regulation of translation affecting a large number of genes involved in prostate carcinogenesis. In this study, through deep-sequencing of size fractionated small RNA libraries we profiled the miRNAs of prostate epithelial (PrEC) and stromal (PrSC) cells. Over 50 million reads were obtained for PrEC in which 860,468 were unique sequences. Similarly, nearly 76 million reads for PrSC were obtained in which over 1 million were unique reads. Expression of many miRNAs of broadly conserved and poorly conserved miRNA families were identified. Sixteen highly expressed miRNAs with significant change in expression in PrSC than PrEC were further analyzed in silico. ConsensusPathDB showed the target genes of these miRNAs were significantly involved in adherence junction, cell adhesion, EGRF, TGF-β and androgen signaling. Let-7 family of tumor-suppressor miRNAs expression was highly pervasive in both, PrEC and PrSC cells. In addition, we have also identified several miRNAs that are unique to PrEC or PrSC cells and their predicted putative targets are a group of transcription factors. This study provides perspective on the miRNA expression in PrEC and PrSC, and reveals a global trend in miRNA interactome. We conclude that the most abundant miRNAs are potential regulators of development and differentiation of the prostate gland by targeting a set of growth factors. Additionally, high level expression of the most members of let-7 family miRNAs suggests their role in the fine tuning of the growth and proliferation of prostate epithelial and stromal cells.

Prostate cancer stroma: an important factor in cancer growth and progression

Reactive stromal changes that occur in different human cancers might play a role in local tumor spreading and progression. Studies done on various human cancers have shown activated stromal cell phenotypes, modified extracellular matrix (ECM) composition, and increased microvessel density. Furthermore, they exhibit biological markers consistent with stroma at the site of wound repair. In prostate cancer, stroma is composed of fibroblasts, myofibroblasts, endothelial cells and immune cells. Predominant cells in the tumorous stroma are, however, fibroblasts/myofibroblasts. They are responsible for the synthesis, deposition and remodeling of the ECM. Epithelial tumorous cells, in interaction with stromal cells and with the help of various molecules of ECM, create a microenvironment suitable for cancer cell proliferation, movement, and differentiation. In this review, we discussed the role of different stromal components in prostate cancer as well as their potential prognostic and therapeutic significance.