New experimental markers for early detection of high-risk prostate cancer: role of cell-cell adhesion and cell migration

The Tumor Microenvironment and Immunotherapy in Prostate and Bladder Cancer

Bladder cancer has been successfully treated with immunotherapy, whereas prostate cancer is a cold tumor with inadequate immune-related treatment response. A greater understanding of the tumor microenvironment and methods for harnessing the immune system to address tumor growth will be needed to improve immunotherapies for both prostate and bladder cancer. Here, we provide an overview of prostate and bladder cancer, including fundamental aspects of the disease and treatment, the elaborate cellular makeup of the tumor microenvironment, and methods for exploiting relevant pathways to develop more effective treatments.

The effects of flutamide on cell-cell junctions in the testis, epididymis, and prostate

In this review, we summarize recent findings on the effect of the anti-androgen flutamide on cell-cell junctions in the male reproductive system. We outline developmental aspects of flutamide action on the testis, epididymis, and prostate, and describe changes in junction protein expression and organization of junctional complexes in the adult boar following prenatal and postnatal exposure. We also discuss findings on the mechanisms by which flutamide induces alterations in cell-cell junctions in reproductive tissues of adult males, with special emphasis on cytoplasmic effects. Based on the results from in vivo and in vitro studies in the rat, we propose that flutamide affects the expression of junction proteins and junction complex structure not only by inhibiting androgen receptor activity, but equally important by modulating protein kinase-dependent signaling in testicular cells. Additionally, results from studies on prostate cancer cell lines point to a role for the cellular molecular outfit in response to flutamide.

Connexin43high prostate cancer cells induce endothelial connexin43 up-regulation through the activation of intercellular ERK1/2-dependent signaling axis

Connexin(Cx)43 regulates the invasive potential of prostate cancer cells and participates in their extravasation. To address the role of endothelial Cx43 in this process, we analyzed Cx43 regulation in human umbilical vein endothelial cells in the proximity of Cx43^high (DU-145 and MAT-LyLu) and Cx43^low prostate cancer cells (PC-3 and AT-2). Endothelial Cx43 up-regulation was observed during the diapedesis of DU-145 and MAT-LyLu cells. This process was attenuated by transient Cx43 silencing in cancer cells and by chemical inhibition of ERK1/2-dependent signaling in endothelial cells. Cx43 expression in endothelial cells was insensitive to the inhibition of gap junctional intercellular coupling between Cx43^high prostate cancer and endothelial cells by 18α-glycyrrhetinic acid. Instead, endothelial Cx43 up-regulation was correlated with the local contraction of endothelial cells and with their activation in the proximity of Cx43^high DU-145 and MAT-LyLu cells. It was also sensitive to pro-inflammatory factors secreted by peripheral blood monocytes, such as TNFα. In contrast to Cx43^low AT-2 cells, Cx43^low PC-3 cells produced angioactive factors that locally activated the endothelial cells in the absence of endothelial Cx43 up-regulation. Collectively, these data show that Cx43^low and Cx43^high prostate cancer cells can adapt discrete, Cx43-independent and Cx43-dependent strategies of diapedesis. Our observations identify a novel strategy of prostate cancer cell diapedesis, which depends on the activation of intercellular Cx43/ERK1/2/Cx43 signaling axis at the interfaces between Cx43^high prostate cancer and endothelial cells.

Anti-androgen 2-hydroxyflutamide modulates cadherin, catenin and androgen receptor phosphorylation in androgen-sensitive LNCaP and androgen-independent PC3 prostate cancer cell lines acting via PI3K/Akt and MAPK/ERK1/2 pathways

This study aimed to investigate rapid effect of anti-androgen 2-hydroxyflutamide (HF) on cadherin/catenin complex and androgen receptor (AR) phosphorylation in prostate cancer cell lines. In addition, a role of PI3K/Akt and MAPK/ERK1/2 pathways in mediating these effects was explored. We have demonstrated that in androgen-sensitive LNCaP cells HF induced rapid increase of E-cadherin phosphorylation at Ser 838/840 (p<0.05) in MAPK/ERK1/2-dependent manner, whereas phosphorylation of β-catenin at Tyr 654 was unchanged. Concomitantly, the reduction of the level of AR phosphorylated at Ser210/213 was found (p<0.01). In androgen-independent PC3 cells HF decreased Tyr 860 N-cadherin and Tyr 645 β-catenin phosphorylation (p<0.01), acting via both MAPK/ERK1/2 and PI3K/Akt pathways. Further, we evidenced that MAPK/ERK1/2 and PI3K/Akt pathways were differentially influenced by HF in LNCaP and PC3 cells. In LNCaP cells, both Akt (p<0.01) and ERK1/2 (p<0.001) phosphorylation were negatively regulated and this effect was mediated by Raf-1 (p<0.05). In contrast, in PC3 cells HF stimulated Akt (p<0.001) and ERK1/2 (p<0.001) activation, but had no effect on the crosstalk between PI3K/Akt and MEK/ERK1/2 pathways at the Raf-1 kinase level. Our findings expand the role of anti-androgen into non-genomic signaling, creating a link between anti-androgen action and phosphorylation of adherens junction proteins in prostate cancer cells.

Bioinformatics analysis of differentially expressed proteins in prostate cancer based on proteomics data

We mined the literature for proteomics data to examine the occurrence and metastasis of prostate cancer (PCa) through a bioinformatics analysis. We divided the differentially expressed proteins (DEPs) into two groups: the group consisting of PCa and benign tissues (P&b) and the group presenting both high and low PCa metastatic tendencies (H&L). In the P&b group, we found 320 DEPs, 20 of which were reported more than three times, and DES was the most commonly reported. Among these DEPs, the expression levels of FGG, GSN, SERPINC1, TPM1, and TUBB4B have not yet been correlated with PCa. In the H&L group, we identified 353 DEPs, 13 of which were reported more than three times. Among these DEPs, MDH2 and MYH9 have not yet been correlated with PCa metastasis. We further confirmed that DES was differentially expressed between 30 cancer and 30 benign tissues. In addition, DEPs associated with protein transport, regulation of actin cytoskeleton, and the extracellular matrix (ECM)–receptor interaction pathway were prevalent in the H&L group and have not yet been studied in detail in this context. Proteins related to homeostasis, the wound-healing response, focal adhesions, and the complement and coagulation pathways were overrepresented in both groups. Our findings suggest that the repeatedly reported DEPs in the two groups may function as potential biomarkers for detecting PCa and predicting its aggressiveness. Furthermore, the implicated biological processes and signaling pathways may help elucidate the molecular mechanisms of PCa carcinogenesis and metastasis and provide new targets for clinical treatment.

ROBO1, a tumor suppressor and critical molecular barrier for localized tumor cells to acquire invasive phenotype: study in African-American and Caucasian prostate cancer models

High-risk populations exhibit early transformation of localized prostate cancer (CaP) disease to metastasis which results in the mortality of such patients. The paucity of knowledge about the molecular mechanism involved in acquiring of metastatic behavior by primary tumor cells and non-availability of reliable phenotype-discriminating biomarkers are stumbling blocks in the management of CaP disease. Here, we determine the role and translational relevance of ROBO1 (an organogenesis-associated gene) in human CaP. Employing CaP-progression models and prostatic tissues of Caucasian and African-American patients, we show that ROBO1 expression is localized to cell-membrane and significantly lost in primary and metastatic tumors. While Caucasians exhibited similar ROBO1 levels in primary and metastatic phenotype, a significant difference was observed between tumor phenotypes in African-Americans. Epigenetic assays identified promoter methylation of ROBO1 specific to African-American metastatic CaP cells. Using African-American CaP models for further studies, we show that ROBO1 negatively regulates motility and invasiveness of primary CaP cells, and its loss causes these cells to acquire invasive trait. To understand the underlying mechanism, we employed ROBO1-expressing/ROBO1-C2C3-mutant constructs, immunoprecipitation, confocal-microscopy and luciferase-reporter techniques. We show that ROBO1 through its interaction with DOCK1 (at SH3-SH2-domain) controls the Rac-activation. However, loss of ROBO1 results in Rac1-activation which in turn causes E-Cadherin/β-catenin cytoskeleton destabilization and induction of cell migration. We suggest that ROBO1 is a predictive biomarker that has potential to discriminate among CaP types, and could be exploited as a molecular target to inhibit the progression of disease as well as treat metastasis in high-risk populations such as African-Americans.

Functional links between Snail-1 and Cx43 account for the recruitment of Cx43-positive cells into the invasive front of prostate cancer

Suppressive function of connexin(Cx)43 in carcinogenesis was recently contested by reports that showed a multifaceted function of Cx43 in cancer progression. These studies did not attempt to model the dynamics of intratumoral heterogeneity involved in the metastatic cascade. An unorthodox look at the phenotypic heterogeneity of prostate cancer cells in vitro enabled us to identify links between Cx43 functions and Snail-1-regulated functional speciation of invasive cells. Incomplete Snail-1-dependent phenotypic shifts accounted for the formation of phenotypically stable subclones of AT-2 cells. These subclones showed diverse predilection for invasive behavior. High Snail-1 and Cx43 levels accompanied high motility and nanomechanical elasticity of the fibroblastoid AT-2_Fi2 subclone, which determined its considerable invasiveness. Transforming growth factor-β and ectopic Snail-1 overexpression induced invasiveness and Cx43 expression in epithelioid AT-2 subclones and DU-145 cells. Functional links between Snail-1 function and Cx43 expression were confirmed by Cx43 downregulation and phenotypic shifts in AT-2_Fi2, DU-145 and MAT-LyLu cells upon Snail-1 silencing. Corresponding morphological changes and Snail-1 downregulation were seen upon Cx43 silencing in AT-2_Fi2 cells. This indicates that feedback loops between both proteins regulate cell invasive behavior. We demonstrate that Cx43 may differentially predispose prostate cancer cells for invasion in a coupling-dependent and coupling-independent manner. When extrapolated to in vivo conditions, these data show the complexity of Cx43 functions during the metastatic cascade of prostate cancer. They may explain how Cx43 confers a selective advantage during cooperative invasion of clonally evolving, invasive prostate cancer cell subpopulations.

The role of adhesion molecules as biomarkers for the aggressive prostate cancer phenotype

BACKGROUND

Currently available methods for diagnosis and staging of prostate cancer lack the sensitivity to distinguish between patients with indolent prostate cancer and those requiring radical treatment. Alterations in key adherens (AJ) and tight junction (TJ) components have been hailed as potential biomarkers for prostate cancer progression but the majority of research has been carried out on individual molecules.

OBJECTIVE

To elucidate a panel of biomarkers that may help distinguish dormant prostate cancer from aggressive metastatic disease.

METHODS

We analysed the expression of 7 well known AJ and TJ components in cell lines derived from normal prostate epithelial tissue (PNT2), non-invasive (CAHPV-10) and invasive prostate cancer (LNCaP, DU145, PC-3) using gene expression, western blotting and immunofluorescence techniques.

RESULTS

Claudin 7, α -catenin and β-catenin protein expression were not significantly different between CAHPV-10 cells and PNT2 cells. However, in PC-3 cells, protein levels for claudin 7, α -catenin were significantly down regulated (-1.5 fold, p = <.001) or undetectable respectively. Immunofluoresence showed β-catenin localisation in PC-3 cells to be cytoplasmic as opposed to membraneous.

CONCLUSION

These results suggest aberrant Claudin 7, α - and β-catenin expression and/or localisation patterns may be putative markers for distinguishing localised prostate cancer from aggressive metastatic disease when used collectively.

Role of adhesion molecules and proliferation hyperplasic, pre neoplastic and neoplastic lesions in canine prostate

E-cadherin and beta-catenin are component of adherens junctions in epithelial cells. Loss of these proteins have been associated with progression of prostatic diseases. We performed immunohistochemistry for E-cadherin, beta-catenin and Ki-67 on canine prostatic lesions. We analyzed the expression of these antibodies in benign prostatic hyperplasia (BPH, n = 22), in pre neoplastic lesions Prostatic Intra-epithelial Neoplasia (PIN), n = 3 and Prostatic Inflammatory Atrophy (PIA), n = 7 and prostate carcinoma (PC, n = 10). In this study, a membranous expression of E-cadherin and beta-catenin and nuclear expression of Ki-67 antigen were demonstrated. The proliferative index was statistically different between carcinomas and BPH and carcinomas and pre-neoplastic lesions. Like in men, the reduction of E-cadherin and increase of Ki-67 expression in neoplastic lesions in dog prostate may be related to the carcinogenic process in this gland.

Identification of androgen-regulated genes in human prostate

Androgens are essential for the development of the prostate and prostate cancer. We examined androgen-regulated gene expression in the human prostate. Samples from benign and malignant prostate tissue and samples containing prostate tissue obtained from prostate cancer patients three days after surgical castration were further processed as probes for a GeneChip array. The comparison of gene expression profiles in castrated samples and in benign or malignant prostate tissue samples revealed androgen-regulated genes. We further evaluated the genes which were differentially expressed in benign and malignant prostate samples. The androgen-regulated expression of dual specificity phosphatase 1 (DUSP1) was confirmed in the LNCaP prostate cancer cell line, as the expression of DUSP1 increased with androgen treatment over the course of time. The expression of the genes CRISP3, PCA3, OR51E2, HOXC6, AGR3, AMACR and SLC14A1 was affected by castration in addition to differential expression in the benign and malignant prostate. These sample results require further investigation for the role of AGR3 and SLC14A1 in prostate cancer as these associations have not been reported previously.

The role of connexins in prostate cancer promotion and progression

Prostate cancer is a prevalent disease that is characterized by a presumably long latency period and a moderate propensity to metastasize. Although a range of mechanisms have been implicated in prostate carcinogenesis, the factors determining the initiation of metastasis remain obscure. The synchronized function of prostate cells depends on their metabolic and electrical coupling; disturbance of these functions has long been suggested to be integral to prostate carcinogenesis. However, although connexins form intercellular channels involved in gap-junction-mediated intercellular coupling (GJIC), whether these proteins also have GJIC-independent roles in cancer progression and metastasis remains a matter of debate. Some data indicate a correlation between connexin expression and the invasive potential of prostate cancer cells, which points to stage-specific functions of connexins during prostate cancer development. For example, restoration of connexin expression seems to be crucial for the formation of invasive cell subsets within heterogeneous prostate cancer cell populations that have undergone aberrant differentiation. Consequently, the clinical application of therapeutic and prophylactic approaches focused on the modulation of connexin expression in prostate cancer cells should be reconsidered.

Steps in prostate cancer progression that lead to bone metastasis

Prostate cancer is a complex disease in which metastasis to the bone is the main cause of death. Initial stages of metastasis are generally similar to those for most solid tumors; however, the mechanisms that underlie the homing of prostate tumor cells to the bone are not completely understood. Prostate cancer bone metastasis is also a microenvironment-driven disease, involving bidirectional interactions between the tumor and the bone microenvironment. In this review, we discuss the current understanding of the biologic processes and regulatory factors involved in the metastasis of prostate cancer cells, and their specific properties that promote growth in bone. Although many of these processes still need to be fully elucidated, a better understanding of the complex tumor/microenvironment interplay is slowly leading to more effective therapies for patients with prostate cancer bone metastases.

Therapeutic targeting of the prostate cancer microenvironment

Solid tumors can be thought of as multicellular 'organs' that consist of a variety of cells as well as a scaffold of noncellular matrix. Stromal-epithelial crosstalk is integral to prostate cancer progression and metastasis, and androgen signaling is an important component of this crosstalk at both the primary and metastatic sites. Intratumoral production of androgen is an important mechanism of castration resistance and has been the focus of novel therapeutic approaches with promising results. Various other pathways are important for stromal-epithelial crosstalk and represent attractive candidate therapeutic targets. Hedgehog signaling has been associated with tumor progression, growth and survival, while Src family kinases have been implicated in tumor progression and in regulation of cancer cell migration. Fibroblast growth factors and transforming growth factor beta signaling regulate cell proliferation, apoptosis and angiogenesis in the prostate cancer microenvironment. Integrins mediate communication between the cell and the extracellular matrix, enhancing growth, migration, invasion and metastasis of cancer cells. The contribution of stromal-epithelial crosstalk to prostate cancer initiation and progression provides the impetus for combinatorial microenvironment-targeting strategies.

New prospective for non-invasive detection, grading, size evaluation, and tumor location of prostate cancer

BACKGROUND

PSA blood test and other present screening tools fail to provide the required sensitivity and specificity and, at early stages, lack correlation with tumor grade, volume, and location. Thus alternative approaches are highly desired. We present and assess a novel method for PCa detection, grading, volume evaluation and tumor location, based on non-invasive zinc concentration mapping in the gland by means of a dedicated rectal probe.

METHODS

Zinc-concentration values measured in histologically examined tissue fragments from needle biopsy of 598 patients were analyzed. They were used to generate computer simulated zinc-concentration maps, further analyzed with image-processing tools. The tumor detection performances versus Gleason grade were assessed.

RESULTS

A significant increase of zinc depletion with increasing Gleason pattern (grade) classification was established. Tumor detection performance in zinc-concentration maps progressively improves with the cancer's first component score. Reliable information on the location, size and Gleason-grade combination of the lesion can be extracted for clinically relevant volumes.

CONCLUSIONS

Zinc depletion in the prostate peripheral zone is the basis for a novel, non-invasive PCa detection, localization, volume evaluation and grading method. Its realization and application as a pre-biopsy and pre-treatment examination, or a follow-up tool, relies on the development of a dedicated transrectal probe. It should have significant impact on biopsy effectiveness, point at a possible extraprostatic extension and provide critical data for focal treatment. The information on tumor grade and distribution may have an important impact on disease management.

Expression and prognostic significance of focal adhesion kinase in hepatocellular carcinoma

AIM

To examine the expressions of focal adhesion kinase (FAK) and its clinical significance in hepatocellular carcinoma (HCC).

METHODS

We determined the expression levels of FAK on both steady-state mRNA and protein levels in 50 HCC samples by quantitative real-time PCR and immunohistochemistry, respectively. The correlations between FAK expression and various clinicopathological parameters were analyzed.

RESULTS

The expression of FAK on the mRNA level was consistent with that on the protein level. FAK mRNA levels in tumor tissues were significantly higher than in the paratumor tissues (0.229 +/- 0.027 vs. 0.163 +/- 0.019; P < 0.001), but lower than in the macroscopic cancer emboli (0.506 +/- 0.155 vs. 0.377 +/- 0.176; P < 0.05). Compared within the tumor tissues, FAK expressions were significantly higher in those with cancer emboli than those without (0.343 +/- 0.05 vs. 0.165 +/- 0.025; P = 0.003). Univariate and multivariate analyses revealed that FAK expression was an independent prognostic factor for disease-free survival and overall survival. Both 3-year disease-free survival rates and overall survival rates in FAK-negative group were significantly higher than in positive group (52 vs. 20% and 72 vs. 29%, P < 0.001).

CONCLUSION

Our results suggest that FAK expression is up-regulated in HCC and its expression is an independent prognostic factor for HCC.

Detecting disease associated modules and prioritizing active genes based on high throughput data

BACKGROUND

The accumulation of high-throughput data greatly promotes computational investigation of gene function in the context of complex biological systems. However, a biological function is not simply controlled by an individual gene since genes function in a cooperative manner to achieve biological processes. In the study of human diseases, rather than to discover disease related genes, identifying disease associated pathways and modules becomes an essential problem in the field of systems biology.

RESULTS

In this paper, we propose a novel method to detect disease related gene modules or dysfunctional pathways based on global characteristics of interactome coupled with gene expression data. Specifically, we exploit interacting relationships between genes to define a gene's active score function based on the kernel trick, which can represent nonlinear effects of gene cooperativity. Then, modules or pathways are inferred based on the active scores evaluated by the support vector regression in a global and integrative manner. The efficiency and robustness of the proposed method are comprehensively validated by using both simulated and real data with the comparison to existing methods.

CONCLUSIONS

By applying the proposed method to two cancer related problems, i.e. breast cancer and prostate cancer, we successfully identified active modules or dysfunctional pathways related to these two types of cancers with literature confirmed evidences. We show that this network-based method is highly efficient and can be applied to a large-scale problem especially for human disease related modules or pathway extraction. Moreover, this method can also be used for prioritizing genes associated with a specific phenotype or disease.

Integrin involvement in freeze resistance of androgen-insensitive prostate cancer

Cryoablation has emerged as a primary therapy to treat prostate cancer. While effective, the assumption that freezing serves as a ubiquitous lethal stress is challenged by clinical experience and experimental evidence demonstrating time-temperature related cell death dependence. The age-related transformation from an androgen-sensitive (AS) to an androgen-insensitive (AI) phenotype is a major challenge in the management of prostate cancer. AI cells exhibit morphological changes and treatment resistance to many therapies. Since this resistance has been linked with α6β4 integrin overexpression as a result of androgen receptor (AR) loss, we investigated whether α6β4 integrin expression, as a result AR loss, contributes to the reported increased freeze tolerance of AI prostate cancer. A series of studies using AS (LNCaP LP and PC-3 AR) and AI (LNCaP HP and PC-3) cell lines were designed to investigate the cellular mechanisms contributing to variations in freezing response. Investigation into α6β4 integrin expression revealed that AI cell lines overexpressed this protein, thereby altering morphological characteristics and increasing adhesion characteristics. Molecular investigations revealed a significant decrease in caspase 8, 9, and 3 levels AI cells following freezing. Inhibition of α6β4 integrin resulted in increased caspase activity following freezing (similar to AS cells) and enhanced cell death. These data demonstrate that AI cells show an increase in post-freeze susceptibility following inhibition of α6β4 integrin function. Further understanding the role of androgen-receptor related α6β4 integrin expression in prostate cancer cells responses to freezing might lead to novel options for neo-adjunctive treatments targeting the AR signaling pathway.

Prostatic chondroitin sulfate is increased in patients with metastatic disease but does not predict survival outcome

BACKGROUND

Previous studies from our laboratory demonstrated a strong association between an elevated level of chondroitin sulfate (CS) in peritumoral stroma and PSA-relapse in patients with early stage disease. In this study we determined whether CS levels could predict overall survival in men diagnosed with advanced prostate cancer subsequently treated by orchiectomy alone.

METHODS

CS was localized in archived prostatic tissues by immunohistochemistry, and the level of CS expression as measured by video image analysis was compared in cohorts of 157 and 60 men with early stage or advanced disease, respectively.

RESULTS

The CS levels in the peritumoral stroma of patients without relapse after treatment for early stage disease was significantly reduced compared to levels in prostate tissue from patients who either relapsed (P = 0.003) or were diagnosed with advanced prostate cancer (P < 0.00001). There was no difference between the median CS level in the peritumoral prostatic stroma of early stage patients that relapsed after treatment and patients diagnosed with advanced prostate cancer. Increased CS levels (P < 0.0001) and high Gleason score (P < 0.0001) were associated with an increased rate of PSA-relapse in the cohort of patients with early stage disease. However, neither CS level nor Gleason score alone or in combination could predict survival outcome in patients with advanced prostate cancer following androgen deprivation therapy.

CONCLUSIONS

Although peritumoral CS levels and Gleason score are strong predictors of relapse-free survival in early stage prostate cancer patients, neither peritumoral CS levels nor Gleason score can predict survival outcome in patients with advanced disease.

Vasoactive intestinal peptide behaves as a pro-metastatic factor in human prostate cancer cells

BACKGROUND

There is little known on the involvement of vasoactive intestinal peptide (VIP) in the metastatic cascade of human prostate cancer, that is, cell proliferation, cell-cell adhesion, extracellular-matrix degradation, and migration/invasion. Here we evaluated the expression of related biomarker proteins (cyclin D1, metalloproteinases MMP-2 and MMP-9, and E-cadherin) in human androgen-dependent (LNCaP) and independent (PC3) prostate cancer cells.

METHODS

Reverse transcriptase (RT)-polymerase chain reaction (PCR), gelatin zymography, Western blotting, confocal immunofluorescence microscopy, and assays on cell proliferation, adhesion, wound-healing, migration and random homing were performed.

RESULTS

VIP increased cell proliferation and cyclin D1 expression whereas it decreased cell adhesion and E-cadherin expression in LNCaP and PC3 cells. VIP enhanced the gelatinolytic activity of MMP-2 and MMP-9. Semiquantitative RT-PCR assays showed that VIP stimulated mRNA levels of these MMPs and suppressed mRNA levels of its inhibitory protein RECK. VIP promoted cell invasion and migration, and the responses were faster according to the most aggressive status in cancer progression (androgen-independence). The involvement of nuclear factor-kappaB (NF-kappaB) was demonstrated since the anti-inflammatory agent curcumin blocked VIP effects on the above biomarkers in both cell lines.

CONCLUSIONS

Taken together, these results and the presence of kappaB sites on gene promoter of cyclin D1, MMPs and, possibly, E-cadherin suggest that VIP may act as a cytokine in an early metastatic stage of human prostate cancer through the NF-kappaB/MMPs-RECK/E-cadherin system. Our findings may help to define novel targets and agents with potential usefulness in prostate cancer therapy.