Wnt/β-catenin signalling in prostate cancer

Overexpression of salusin-β is associated with poor prognosis in ovarian cancer

Ovarian cancer is recognized as one of the worst gynecologic malignancies associated with rapid metastasis and poor overall survival rate. The identified valuable molecular biomarkers criticize importance of timely diagnosis for ovarian cancer. Salusin-β levels are dramatically increased in women with polycystic ovarian syndrome. However, the roles of salusin-β in ovarian cancer have yet to be fully elucidated. A total of 57 paired ovarian cancer specimens and matched adjacent normal tissues were used to measure the salusin-β levels. The prognostic value of salusin-β for tumor progression and survival rate was investigated. The effects of salusin-β on ovarian cancer cell proliferation and epithelial-mesenchymal transition were also explored. The expression of salusin-β was significantly increased in ovarian cancer tissue specimens compared with matched normal adjacent tissue (P<0.05). The high salusin-β level was closely related with FIGO stage and lymph node metastases. The ovarian cancer patients with high salusin-β had a shorter overall survival (P<0.05). Salusin-β obviously enhanced the proliferation and epithelial mesenchymal-transition of SKOV3 cells. Furthermore, salusin-β substantially decreased the expression of p-GSK-3β and GSK-3β, but stimulated the β-catenin expression and downstream genes of wnt/β-catenin including cyclin D1 and C-myc. Our data demonstrated for the first time that upregulated salusin-β may be a novel independent prognostic biomarker for overall survival of ovarian cancer. Salusin-β accelerated the proliferation and epithelial mesenchymal transition of ovarian cancer cells at least partly via activation of Wnt/β-catenin signaling pathway. Salusin-β may be an important target for therapeutic intervention in ovarian cancer.

Inhibition of DIXDC1 by microRNA-1271 suppresses the proliferation and invasion of prostate cancer cells

Disheveled-Axin domain containing 1 (DIXDC1) is involved in the development and progression of multiple cancers. However, the function significance of DIXDC1 in prostate cancer remains unclear. In this study, we investigated the function of DIXDC1 in prostate cancer and the regulation of DIXDC1 by microRNAs (miRNAs). We found that DIXDC1 was highly expressed in prostate cancer cells. Knockdown of DIXDC1 by small interfering RNAs markedly suppressed proliferation, invasion and Wnt signaling in prostate cancer cells. DIXDC1 was identified as a target gene of miR-1271 by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction and Western blot analysis. Furthermore, DIXDC1 expression was inversely correlated with miR-1271 expression in prostate cancer tissues. The overexpression of miR-1271 significantly inhibited proliferation, invasion and Wnt signaling in prostate cancer cells. However, the inhibition of miR-1271 exhibits the opposite effects. Moreover, the overexpression of DIXDC1 significantly reversed the inhibitory effects of miR-1271 overexpression. Taken together, our results suggest that DIXDC1 plays an important role in regulating prostate cancer cell proliferation and invasion. Targeting DIXDC1 by miR-1271 may be a promising therapeutic strategy for prostate cancer.

Anti-Cancer Phytometabolites Targeting Cancer Stem Cells

Medicinal plants are a plentiful source of bioactive molecules with much structural diversity. In cancer treatment, molecules obtained from plants represent an attractive alternative to other treatments because several plant-derived compounds have exhibited lower toxicity and higher selectivity against cancer cells. In this review, we focus on the possible application of bioactive molecules obtained from plants against more primitive cell populations in cancers, cancer stem cells. Cancer stem cells are present in several kinds of tumors and are responsible for recurrences and metastases. Common anti-cancer drugs exhibit lower effectiveness against cancer stem cells because of their biological features. However, recently discovered natural phytometabolites exert cytotoxic effects on this rare population of cells in cancers. Therefore, this review presents the latest research on promising compounds from plants that can act as antitumor drugs and that mainly affect stem cell populations in cancers.

A Tale of Two Signals: AR and WNT in Development and Tumorigenesis of Prostate and Mammary Gland

Prostate cancer (PCa) is one of the most common cancers and among the leading causes of cancer deaths for men in industrialized countries. It has long been recognized that the prostate is an androgen-dependent organ and PCa is an androgen-dependent disease. Androgen action is mediated by the androgen receptor (AR). Androgen deprivation therapy (ADT) is the standard treatment for metastatic PCa. However, almost all advanced PCa cases progress to castration-resistant prostate cancer (CRPC) after a period of ADT. A variety of mechanisms of progression from androgen-dependent PCa to CRPC under ADT have been postulated, but it remains largely unclear as to when and how castration resistance arises within prostate tumors. In addition, AR signaling may be modulated by extracellular factors among which are the cysteine-rich glycoproteins WNTs. The WNTs are capable of signaling through several pathways, the best-characterized being the canonical WNT/β-catenin/TCF-mediated canonical pathway. Recent studies from sequencing PCa genomes revealed that CRPC cells frequently harbor mutations in major components of the WNT/β-catenin pathway. Moreover, the finding of an interaction between β-catenin and AR suggests a possible mechanism of cross talk between WNT and androgen/AR signaling pathways. In this review, we discuss the current knowledge of both AR and WNT pathways in prostate development and tumorigenesis, and their interaction during development of CRPC. We also review the possible therapeutic application of drugs that target both AR and WNT/β-catenin pathways. Finally, we extend our review of AR and WNT signaling to the mammary gland system and breast cancer. We highlight that the role of AR signaling and its interaction with WNT signaling in these two hormone-related cancer types are highly context-dependent.

Anticancer activity and potential mechanisms of 1C, a ginseng saponin derivative, on prostate cancer cells

Background

AD-2 (20(R)-dammarane-3b, 12b, 20, 25-tetrol; 25-OH-PPD) is a ginsenoside and isolated from Panax ginseng, showing anticancer activity against extensive human cancer cell lines. In this study, effects and mechanisms of 1C ((20R)-3b-O-(L-alanyl)-dammarane-12b, 20, 25-triol), a modified version of AD-2, were evaluated for its development as a novel anticancer drug.

Methods

MTT assay was performed to evaluate cell cytotoxic activity. Cell cycle and levels of reactive oxygen species (ROS) were determined using flow cytometry analysis. Western blotting was employed to analyze signaling pathways.

Results

1C concentration-dependently reduces prostate cancer cell viability without affecting normal human gastric epithelial cell line-1 viability. In LNCaP prostate cancer cells, 1C triggered apoptosis via Bcl-2 family-mediated mitochondria pathway, downregulated expression of mouse double minute 2, upregulated expression of p53 and stimulated ROS production. ROS scavenger, N-acetylcysteine, can attenuate 1C-induced apoptosis. 1C also inhibited the proliferation of LNCaP cells through inhibition on Wnt/β-catenin signaling pathway.

Conclusion

1C shows obvious anticancer activity based on inducing cell apoptosis by Bcl-2 family-mediated mitochondria pathway and ROS production, inhibiting Wnt/β-catenin signaling pathway. These findings demonstrate that 1C may provide leads as a potential agent for cancer therapy.

•

Ginseng saponin derivative 1C was obtained by structural modification.

•

Anticancer activity of 1C is much better than that of the original compound AD-2 on cancer cells.

•

1C induces cell apoptosis by Bcl-2 family-mediated mitochondria pathway and ROS production.

•

1C inhibits Wnt/β-catenin signaling pathway

Inherited Variants in Wnt Pathway Genes Influence Outcomes of Prostate Cancer Patients Receiving Androgen Deprivation Therapy

Aberrant Wnt signaling has been associated with many types of cancer. However, the association of inherited Wnt pathway variants with clinical outcomes in prostate cancer patients receiving androgen deprivation therapy (ADT) has not been determined. Here, we comprehensively studied the contribution of common single nucleotide polymorphisms (SNPs) in Wnt pathway genes to the clinical outcomes of 465 advanced prostate cancer patients treated with ADT. Two SNPs, adenomatous polyposis coli (APC) rs2707765 and rs497844, were significantly (p ≤ 0.009 and q ≤ 0.043) associated with both prostate cancer progression and all-cause mortality, even after multivariate analyses and multiple testing correction. Patients with a greater number of favorable alleles had a longer time to disease progression and better overall survival during ADT (p for trend ≤ 0.003). Additional, cDNA array and in silico analyses of prostate cancer tissue suggested that rs2707765 affects APC expression, which in turn is correlated with tumor aggressiveness and patient prognosis. This study identifies the influence of inherited variants in the Wnt pathway on the efficacy of ADT and highlights a preclinical rationale for using APC as a prognostic marker in advanced prostate cancer.

Analysis of Zinc-Exporters Expression in Prostate Cancer

Maintaining optimal intracellular zinc (Zn) concentration is crucial for critical cellular functions. Depleted Zn has been associated with prostate cancer (PCa) progression. Solute carrier family 30 (SLC30A) proteins maintain cytoplasmic Zn balance by exporting Zn out to the extracellular space or by sequestering cytoplasmic Zn into intracellular compartments. In this study, we determined the involvement of Zn-exporters, SLC30A 1-10 in PCa, in the context of racial health disparity in human PCa samples obtained from European-American (EA) and African-American (AA) populations. We also analyzed the levels of Zn-exporters in a panel of PCa cells derived from EA and AA populations. We further explored the expression profile of Zn-exporters in PCa using Oncomine database. Zn-exporters were found to be differentially expressed at the mRNA level, with a significant upregulation of SLC30A1, SLC30A9 and SLC30A10, and downregulation of SLC30A5 and SLC30A6 in PCa, compared to benign prostate. Moreover, Ingenuity Pathway analysis revealed several interactions of Zn-exporters with certain tumor suppressor and promoter proteins known to be modulated in PCa. Our study provides an insight regarding Zn-exporters in PCa, which may open new avenues for future studies aimed at enhancing the levels of Zn by modulating Zn-transporters via pharmacological means.

Glutathione Peroxidase 3 Inhibits Prostate Tumorigenesis in TRAMP Mice

BACKGROUND

Glutathione peroxidase 3 (GPx3) is involved in protecting cells from oxidative damage, and down-regulated levels of expression have been found in prostate cancer samples. We hypothesize that loss of the GPx3 increases the rate of prostate carcinogenesis and generated GPx3-deficient transgenic adenocarcinoma of the mouse prostate (TRAMP) mice.

METHODS

Prostate cancer incidence and progression were determined in TRAMP, TRAMP/GPx3 (+/-) HET, and TRAMP/GPx3 (-/-) KO mice at 8, 16, and 20 weeks of age.

RESULTS

We found that GPx3 expression was decreased in TRAMP mice and not detected in GPx3 KO mice both in mRNA and protein levels. Disruption of GPx3 expression in TRAMP mice increased the GU tract weights and the histopathological scores in each lobes with increased proliferation rates. Moreover, inactivation of one (+/-) or both (-/-) alleles of GPx3 resulted in increase in prostate cancer incidence with activated Wnt/β-catenin pathway.

CONCLUSIONS

Our results provide the first in vivo molecular genetic evidence that GPx3 does indeed function as a tumor suppressor during prostate carcinogenesis. Prostate 76:1387-1398, 2016. © 2016 Wiley Periodicals, Inc.

Prodigiosin inhibits Wnt/β-catenin signaling and exerts anticancer activity in breast cancer cells

Prodigiosin, a natural red pigment produced by numerous bacterial species, has exhibited promising anticancer activity; however, the molecular mechanisms of action of prodigiosin on malignant cells remain unclear. Aberrant activation of the Wnt/β-catenin signaling cascade is associated with numerous human cancers. In this study, we identified prodigiosin as a potent inhibitor of the Wnt/β-catenin pathway. Prodigiosin blocked Wnt/β-catenin signaling by targeting multiple sites of this pathway, including the low-density lipoprotein-receptor-related protein (LRP) 6, Dishevelled (DVL), and glycogen synthase kinase-3β (GSK3β). In breast cancer MDA-MB-231 and MDA-MB-468 cells, nanomolar concentrations of prodigiosin decreased phosphorylation of LRP6, DVL2, and GSK3β and suppressed β-catenin-stimulated Wnt target gene expression, including expression of cyclin D1. In MDA-MB-231 breast cancer xenografts and MMTV-Wnt1 transgenic mice, administration of prodigiosin slowed tumor progression and reduced the expression of phosphorylated LRP6, phosphorylated and unphosphorylated DVL2, Ser9 phosphorylated GSK3β, active β-catenin, and cyclin D1. Through its ability to inhibit Wnt/β-catenin signaling and reduce cyclin D1 levels, prodigiosin could have therapeutic activity in advanced breast cancers.

Stearoyl CoA desaturase-1: New insights into a central regulator of cancer metabolism

The processes of cell proliferation, cell death and differentiation involve an intricate array of biochemical and morphological changes that require a finely tuned modulation of metabolic pathways, chiefly among them is fatty acid metabolism. The critical participation of stearoyl CoA desaturase-1 (SCD1), the fatty acyl Δ9-desaturing enzyme that converts saturated fatty acids (SFA) into monounsaturated fatty acids (MUFA), in the mechanisms of replication and survival of mammalian cells, as well as their implication in the biological alterations of cancer have been actively investigated in recent years. This review examines the growing body of evidence that argues for a role of SCD1 as a central regulator of the complex synchronization of metabolic and signaling events that control cellular metabolism, cell cycle progression, survival, differentiation and transformation to cancer.

Frequently rearranged in advanced T‑cell lymphomas‑1 demonstrates oncogenic properties in prostate cancer

Prostate cancer is the fifth most common cause of cancer-associated mortality for males worldwide. Although dysregulation of the β-catenin/T-cell factor (TCF) pathway has been previously reported in prostate cancer, the mechanisms underlying this process remain unknown. Frequently rearranged in advanced T-cell lymphomas-1 (FRAT1) functions as a positive regulator of the β-catenin/TCF signaling pathway. However, to the best of our knowledge, the molecular association between FRAT1 and the β-catenin/TCF pathway in prostate cancer has not been investigated. In the present study, FRAT1 expression was analyzed in normal prostate tissues and prostate adenocarcinoma samples using publicly available databases, a commercial tissue microarray and immunohistochemistry techniques. In addition, FRAT1 expression levels were altered by overexpression or RNA interference-mediated depletion in prostate cancer cells. The effects of FRAT1 expression on tumor growth were determined using cell growth curves in vitro and xenografts in nude mice in vivo. The effects of FRAT1 on β-catenin/TCF activity were measured using the TOPFLASH reporter assay. FRAT1 was expressed exclusively in the nuclei of normal prostate basal cells, and nuclear FRAT1 was detected in 68% (40/59) of prostate adenocarcinoma samples. In addition, FRAT1 activated the TCF luciferase reporter gene promoter in prostate cancer cells, and was observed to promote the growth of prostate cancer cells in vitro. Furthermore, FRAT1 expression was sufficient to transform NIH3T3 mouse embryonic fibroblast cells and lead to tumor formation in vivo. These results suggest that FRAT1 demonstrates oncogenic properties in prostate cancer, potentially by suppressing the inhibitory effect of nuclear glycogen synthase 3β against β-catenin/TCF activity, thus activating the Wnt/β-catenin signaling pathway and promoting cell growth.

Self-regulation of functional pathways by motifs inside the disordered tails of beta-catenin

BACKGROUND

Beta-catenin has two major functions: coordinating cell-cell adhesion by interacting with cadherin in cadherin junction formation pathway; and regulating gene expression through Wnt signaling pathway. Accomplishing these two functions requires synergistic action of various sequential regions of the same beta-Catenin molecule, including the N-terminal tail, the middle armadillo domain, and the C-terminal tail. Although the middle armadillo domain is the major functional unit of beta-Catenin, the involvement of tails in the regulation of interaction between beta-Catenin and its partners has been well observed. Nonetheless, the regulatory processes of both tails are still elusive. In addition, it is interesting to note that the three sequential regions have different structural features: The middle armadillo domain is structured, but both N- and C-terminal tails are disordered. This observation leads to another important question on the functions and mechanisms of disordered tails, which is also largely unknown.

RESULTS

In this study, we focused on the characterization of sequential, structural, and functional features of the disordered tails of beta-Catenin. We identified multiple functional motifs and conserved sequence motifs in the disordered tails, discovered the correlation between cancer-associated mutations and functional motifs, explored the abundance of protein intrinsic disorder in the interactomes of beta-Catenin, and elaborated a working model on the regulatory roles of disordered tails in the functional pathways of beta-Catenin.

CONCLUSION

Disordered tails of beta-Catenin contain multiple functional motifs. These motifs interact with each other and the armadillo domain of beta-catenin to regulate the function of beta-Catenin in both cadherin junction formation pathway and Wnt signaling pathway.

SFRP1 repression in prostate cancer is triggered by two different epigenetic mechanisms

Worldwide, prostate cancer (PCa) is the second cause of death from malignant tumors among men. Establishment of aberrant epigenetic modifications, such as histone post-translational modifications (PTMs) and DNA methylation (DNAme) produce alterations of gene expression that are common in PCa. Genes of the SFRP family are tumor suppressor genes that are frequently silenced by DNA hypermethylation in many cancer types. The SFRP family is composed of 5 members (SFRP1-5) that modulate the WNT pathway, which is aberrantly activated in PCa. The expression of SFRP genes in PCa and their regulation by DNAme has been controversial. Our objective was to determine the gene expression pattern of the SFRP family in prostatic cell lines and fresh frozen tissues from normal prostates (NP), benign prostatic hyperplasia (BPH) and prostate cancer (PCa), by qRT-PCR, and their DNAme status by MSP and bisulfite sequencing. In prostatic cancer cell lines, the 5 SFRPs showed significantly decreased expression levels compared to a control normal prostatic cell line (p<0.0001). In agreement, SFRP1 and SFRP5 genes showed decreased expression levels in CaP fresh frozen tissues compared to NP (p<0.01), while a similar trend was observed for SFRP2. Conversely, increased levels of SFRP4 expression were found in PCa compared to BPH (p<0.01). Moreover, SFRP2, SFRP3, and SFRP5 showed DNA hypermethylation in PCa cell lines. Interestingly, we observed DNA hypermethylation at the promoter of SFRP1 in the PC3 cell line, but not in LNCaP. However, in the LNCaP cell line we found an aberrant gain of the repressive histone posttranslational modification Histone H3 lysine 27 trimethylation (H3K27me3). In conclusion, decreased expression by DNA hypermethylation of SFRP5 is a common feature of PCa, while decreased expression of SFRP1 can be due to DNA hypermethylation, but sometimes an aberrant gain of the histone mark H3K27me3 is observed instead.

Genetic variants of the Wnt signaling pathway as predictors of aggressive disease and reclassification in men with early stage prostate cancer on active surveillance

Little is known about the genetic predictors of prostate cancer aggressiveness and reclassification in men with localized prostate cancer undergoing active surveillance. The Wnt signaling pathway is important for prostate cancer development and progression. Identifying genetic variants associated with prostate cancer aggressiveness and reclassification may have a potential role in the management of localized patients. In this study, we used a three-phase design. In phases I and II prostate cancer patient cohort, 578 single nucleotide polymorphisms (SNPs) from 45 genes of the Wnt signaling pathway were analyzed in 1762 localized prostate cancer patients. Twelve SNPs from four regions were significantly associated with aggressive disease, among which, three linked SNPs in CSNK1A1 at 5q32 (represented by rs752822) may differentiate GS 4+3 from GS 3+4 patients (OR = 1.44, 95% CI = 1.12-1.87, P = 4.76×10(-3)). In phase III active surveillance (AS) cohort, genotyping of rs752822 (candidate from phases I and II) and previously identified rs2735839 were determined in 494 GS ≤7 patients. We found a significant association between rs2735839 and prostate cancer reclassification in the AS cohort (AG + AA versus GG, HR = 1.59, 95% CI = 1.11-2.28, P = 0.012) and a suggestive association of rs752822. Jointly, rs752822 and rs2735839 showed good potentials in risk-stratifying GS 7 patients and predicting disease reclassification (OR = 2.71, 95% CI = 1.62-4.51, P = 1×10(-4) in phase II; HR = 1.89, 95% CI = 1.13-3.18, P = 0.016 in phase III). In summary, rs752822 and rs2735839 may assist in risk-stratifying GS 7 patients and predict prostate cancer reclassification. The significant associations were independent from GS, T stage and PSA levels at baseline.

Estrogen receptor beta (ERβ) mediates expression of β-catenin and proliferation in prostate cancer cell line PC-3

The aim of the present study was to characterize the mechanism underlying estrogen effects on the androgen-independent prostate cancer cell line PC-3. 17β-estradiol and the ERβ-selective agonist DPN, but not the ERα-selective agonist PPT, increased the incorporation of [methyl-(3)H]thymidine and the expression of Cyclin D2, suggesting that ERβ mediates the proliferative effect of estrogen on PC-3 cells. In addition, upregulation of Cyclin D2 and incorporation of [methyl-(3)H]thymidine induced by 17β-estradiol and DPN were blocked by the ERβ-selective antagonist PHTPP in PC-3 cells. Upregulation of Cyclin D2 and incorporation of [methyl-(3)H]thymidine induced by DPN were also blocked by PKF118-310, a compound that disrupts β-catenin-TCF (T-cell-specific transcription factor) complex, suggesting the involvement of β-catenin in the estradiol effects in PC-3 cells. A diffuse immunostaining for non-phosphorylated β-catenin was detected in the cytoplasm of PC-3 cells. Low levels of non-phosphorylated β-catenin immunostaining were also detected near the plasma membrane and in nuclei. Treatment of PC-3 cells with 17β-estradiol or DPN markedly increased non-phosphorylated β-catenin expression. These effects were blocked by pretreatment with the ERβ-selective antagonist PHTPP, PI3K inhibitor Wortmannin or AKT inhibitor MK-2206, indicating that ERβ-PI3K/AKT mediates non-phosphorylated β-catenin expression. Cycloheximide blocked the DPN-induced upregulation of non-phosphorylated β-catenin, suggesting de novo synthesis of this protein. In conclusion, these results suggest that estrogen may play a role in androgen-independent prostate cancer cell proliferation through a novel pathway, involving ERβ-mediated activation of β-catenin.

SPOP promotes tumor progression via activation of β-catenin/TCF4 complex in clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer, about one third of the cases are diagnosed at advanced stages with metastases and effective treatments for metastatic RCC are lacking. The molecular events supporting RCC progression remain poorly understood. SPOP, an E3 ubiquitin ligase component, was recently showed to sufficiently promote RCC tumorigenesis, however, other potential functions of SPOP in RCC have not been studied. In the present investigation, by assessing the immunohistochemical staining of SPOP in urological tumors, we found the protein was highly expressed in RCC, in particular, it was specifically expressed in clear cell RCC. cDNA microarray data showed that SPOP mRNA level was significantly increased in clear cell RCC compared to normal kidney tissues, which might be the result of the abnormal DNA copy number of this gene. More interestingly, SPOP was positive in tumors with local invasion or metastasis, and it was associated with tumor recurrence-free survival of clear cell RCC patients. Further in vitro assays demonstrated that SPOP drove RCC epithelial-mesenchymal transition (EMT) and promoted cell invasion. Mechanistically, SPOP enhanced β-catenin protein expression as well as its nuclear translocation, and elevated TCF4 expression. Both β-catenin and TCF4 upregulated the critical EMT-inducing transcription factor ZEB1, which functioned as an effector of β-catenin/TCF4 signaling in RCC invasion. These data identified SPOP as a new marker and prognostic factor for clear cell RCC, and its functions provide new insight into the molecular mechanisms of RCC progression, in which SPOP appears to be an EMT activator.

SOX9 drives WNT pathway activation in prostate cancer

The transcription factor SOX9 is critical for prostate development, and dysregulation of SOX9 is implicated in prostate cancer (PCa). However, the SOX9-dependent genes and pathways involved in both normal and neoplastic prostate epithelium are largely unknown. Here, we performed SOX9 ChIP sequencing analysis and transcriptome profiling of PCa cells and determined that SOX9 positively regulates multiple WNT pathway genes, including those encoding WNT receptors (frizzled [FZD] and lipoprotein receptor-related protein [LRP] family members) and the downstream β-catenin effector TCF4. Analyses of PCa xenografts and clinical samples both revealed an association between the expression of SOX9 and WNT pathway components in PCa. Finally, treatment of SOX9-expressing PCa cells with a WNT synthesis inhibitor (LGK974) reduced WNT pathway signaling in vitro and tumor growth in murine xenograft models. Together, our data indicate that SOX9 expression drives PCa by reactivating the WNT/β-catenin signaling that mediates ductal morphogenesis in fetal prostate and define a subgroup of patients who would benefit from WNT-targeted therapy.

Adhesion Molecules: Master Controllers of the Circulatory System

This manuscript will review our current understanding of cellular adhesion molecules (CAMs) relevant to the circulatory system, their physiological role in control of vascular homeostasis, innate and adaptive immune responses, and their importance in pathophysiological (disease) processes such as acute lung injury, atherosclerosis, and pulmonary hypertension. This is a complex and rapidly changing area of research that is incompletely understood. By design, we will begin with a brief overview of the structure and classification of the major groups of adhesion molecules and their physiological functions including cellular adhesion and signaling. The role of specific CAMs in the process of platelet aggregation and hemostasis and leukocyte adhesion and transendothelial migration will be reviewed as examples of the complex and cooperative interplay between CAMs during physiological and pathophysiological processes. The role of the endothelial glycocalyx and the glycobiology of this complex system related to inflammatory states such as sepsis will be reviewed. We will then focus on the role of adhesion molecules in the pathogenesis of specific disease processes involving the lungs and cardiovascular system. The potential of targeting adhesion molecules in the treatment of immune and inflammatory diseases will be highlighted in the relevant sections throughout the manuscript.

Design, Synthesis, and Structural Optimization of Lycorine-Derived Phenanthridine Derivatives as Wnt/β-Catenin Signaling Pathway Agonists

Lycorine is a benzylphenethylamine-type alkaloid member of the Amaryllidaceae family. A lycorine derivative, HLY78, was previously identified as a new Wnt/β-catenin signaling pathway agonist that targets the DAX domain of axin. Herein, the structural optimization of HLY78 and analyses of the structure-activity relationships of lycorine-derived phenanthridine derivatives as agonists of the Wnt/β-catenin signaling pathway are presented. This research suggests that triazole groups are important pharmacophores for Wnt activation; triazole groups at C-8 and C-9 of phenanthridine compounds markedly enhanced Wnt activation. A C-11-C-12 single bond is also important for Wnt activation. On the basis of these findings, two Wnt agonists were designed and synthesized. The results for these agonists indicated that the combination of a 4-ethyldihydrophenanthridine skeleton and a triazole substituent improves Wnt activation. These compounds may be useful in further pharmacological or biological studies.

MicroRNA-34a regulates WNT/TCF7 signaling and inhibits bone metastasis in Ras-activated prostate cancer

Aberrant activation of Ras and WNT signaling are key events that have been shown to be up-regulated in prostate cancer that has metastasized to the bone. However, the regulatory mechanism of combinatorial Ras and WNT signaling in advanced prostate cancer is still unclear. TCF7, a WNT signaling-related gene, has been implicated as a critical factor in bone metastasis, and here we show that TCF7 is a direct target of miR-34a. In samples of prostate cancer patients, miR-34a levels are inversely correlated with TCF7 expression and a WNT dependent gene signature. Ectopic miR-34a expression inhibited bone metastasis and reduced cancer cell proliferation in a Ras-dependent xenograft model. We demonstrate that miR-34a can directly interfere with the gene expression of the anti-proliferative BIRC5, by targeting BIRC5 3′UTR. Importantly, BIRC5 overexpression was sufficient to reconstitute anti-apoptotic signaling in cells expressing high levels of miR-34a. In prostate cancer patients, we found that BIRC5 levels were positively correlated with a Ras signaling signature expression. Our data show that the bone metastasis and anti-apoptotic effects found in Ras signaling-activated prostate cancer cells require miR-34a deficiency, which in turn aids in cell survival by activating the WNT and anti-apoptotic signaling pathways thereby inducing TCF7 and BIRC5 expressions.

Expression and colocalization of β-catenin and lymphoid enhancing factor-1 in prostate cancer progression

The purpose of this study was to objectively investigate β-catenin and LEF1 abundance, subcellular localization, and colocalization across benign and staged prostate cancer (PCa) specimens. A tissue microarray containing tumor-adjacent histologically benign prostate tissue (BPT; n = 48 patients), high-grade prostatic intraepithelial neoplasia (HGPIN; n = 25), localized PCa (n = 42), aggressive PCa (n = 31), and metastases (n = 22) was stained using multiplexed immunohistochemistry with antibodies toward E-cadherin, β-catenin, and LEF1. Multispectral imaging was used for quantitation, and protein expression and colocalization was evaluated across PCa progression. Stromal nuclear β-catenin abundance was greater in HGPIN and PCa compared with BPT (P < .05 for both), and epithelial nuclear β-catenin abundance was lower in metastatic PCa than in BPT (P < .05 for both). Epithelial and stromal nuclear LEF1 abundance was greater in HGPIN compared with BPT, whereas epithelial nuclear LEF1 was also greater in metastases. The proportion of epithelial and stromal nuclear double-positive β-catenin(+)/LEF1(+) cells was greater in HGPIN compared with BPT. In addition, the proportion of epithelial β-catenin(+)/LEF1(+) cells was greater in localized PCa and metastases compared with BPT. A significant amount of stromal cells were positive for LEF1 but not β-catenin. β-Catenin and LEF1 abundance were negatively correlated in the epithelium (P < .0001) but not the stroma (P > .05). We conclude that β-catenin and LEF1 colocalization is increased in HGPIN and metastasis relative to BPT, suggesting a role for β-catenin/LEF1-mediated transcription in both malignant transformation and metastasis of PCa. Furthermore, our results suggest that LEF1 abundance alone is not a reliable readout for β-catenin activity in prostate tissues.

MicroRNA-613 represses prostate cancer cell proliferation and invasion through targeting Frizzled7

A growing number of studies have indicated that microRNAs (miRNAs) are critical regulators of carcinogenesis and cancer progression and may serve as potential therapeutic tools for cancer therapy. Frizzled7 (Fzd7), the most important receptor of the Wnt signaling pathway, is extensively involved in cancer development and progression. However, the role of Fzd7 in prostate cancer remains unclear. In this study, we aimed to explore the expression of Fzd7 in prostate cancer and test whether modulating Fzd7 expression by miR-613 would have an impact on prostate cancer cell proliferation and invasion. We found that Fzd7 was highly expressed in prostate cancer cell lines. Through bioinformatics analysis, Fzd7 was predicted as a target gene of miR-613, which was validated by dual-luciferase reporter assays, real-time quantitative polymerase chain reaction and Western blot analysis. By gain of function experiments, we showed that overexpression of miR-613 significantly suppressed prostate cancer cell proliferation and invasion. Furthermore, miR-613 overexpression markedly downregulated the Wnt signaling pathway. Through a rescue experiment, we showed that overexpression of Fzd7 could abrogate the inhibitory effect of miR-613 on cell proliferation and invasion as well as Wnt signaling. Additionally, these results were further strengthened by data showing that miR-613 was significantly downregulated in prostate cancer tissues, exhibiting an inverse correlation with Fzd7 expression. In conclusion, our study suggests that miR-613 functions as a tumor suppressor, partially through targeting Fzd7, and is a potential therapeutic target for prostate cancer.

Prostate cancer stem cells: deciphering the origins and pathways involved in prostate tumorigenesis and aggression

The cells of the prostate gland are dependent on cell signaling pathways to regulate their growth, maintenance and function. However, perturbations in key signaling pathways, resulting in neoplastic transformation of cells in the prostate epithelium, are likely to generate subtypes of prostate cancer which may subsequently require different treatment regimes. Accumulating evidence supports multiple sources of stem cells in the prostate epithelium with distinct cellular origins for prostate tumorigenesis documented in animal models, while human prostate cancer stem-like cells (PCSCs) are typically enriched by cell culture, surface marker expression and functional activity assays. As future therapies will require a deeper understanding of its cellular origins as well as the pathways that drive PCSC maintenance and tumorigenesis, we review the molecular and functional evidence supporting dysregulation of PI3K/AKT, RAS/MAPK and STAT3 signaling in PCSCs, the development of castration resistance, and as a novel treatment approach for individual men with prostate cancer.

WWOX suppresses prostate cancer cell progression through cyclin D1-mediated cell cycle arrest in the G1 phase

WW domain-containing oxidoreductase (WWOX) has been reported to be a tumor suppressor in multiple cancers, including prostate cancer. WWOX can induce apoptotic responses to inhibit tumor progression, and the other mechanisms of WWOX in tumor suppression have also been reported recently. In this study, we found significant down-regulation of WWOX in prostate cancer specimens and prostate cancer cell lines compared with the normal controls. In addition, an ectopically increased WWOX expression repressed tumor progression both in vitro and in vivo. Interestingly, overexpression of WWOX in 22Rv1 cells led to cell cycle arrest in the G1 phase but did not affect sub-G1 in flow cytometry. GFP-WWOX overexpressed 22Rv1 cells were shown to inhibit cell cycle progression into mitosis under nocodazole treatment in flow cytometry, immunoblotting and GFP fluorescence. Further, cyclin D1 but not apoptosis correlated genes were down-regulated by WWOX both in vitro and in vivo. Restoration of cyclin D1 in the WWOX-overexpressed 22Rv1 cells could abolish the WWOX-mediated tumor repression. In addition, WWOX impair c-Jun-mediated cyclin D1 promoter activity. These results suggest that WWOX inhibits prostate cancer progression through negatively regulating cyclin D1 in cell cycle lead to G1 arrest. In summary, our data reveal a novel mechanism of WWOX in tumor suppression.

Divergent Androgen Receptor and Beta-Catenin Signaling in Prostate Cancer Cells

Despite decades of effort to develop effective therapy and to identify promising new drugs, prostate cancer is lethal once it progresses to castration-resistant disease. Studies show mis-regulation of multiple pathways in castration-resistant prostate cancer (CRPC), reflecting the heterogeneity of the tumors and also hinting that targeting androgen receptor (AR) pathway alone might not be sufficient to treat CRPC. In this study, we present evidence that the Wnt/β-catenin pathway might be activated in prostate cancer cells after androgen-deprivation to promote androgen-independent growth, partly through enhanced interaction of β-catenin with TCF4. Androgen-independent prostate cancer cells were more prone to activate a Wnt-reporter, and inhibition of the Wnt/β-catenin pathway increased sensitivity of these cells to the second-generation antiandrogen, enzalutamide. Combined treatment of enzalutamide and Wnt/β-catenin inhibitor showed increased growth repression in both androgen-dependent and -independent prostate cancer cells, suggesting therapeutic potential for this approach.

Aberrant Wnt/β-Catenin Signaling Pathway in Testis of Azoospermic Men​

PURPOSE

The Importance and key role of Wnt/β-catenin signaling pathway in spermatogenesis is known. Abnormalities of this pathway in Sertoli and germ cells leads to infertility. Leydig cells play an important role in spermatogenesis and male reproduction. As of now, exact position of the Wnt/β-catenin signaling pathway disorders in the tissue and possible involvement of Leydig cells has not been investigated.

METHODS

Samples of our previous study were used for common Y chromosome microdeletions screening and common CFTR gene mutations.1 β-catenin gene expression were evaluated and compared between testicular tissue obtained by testicular sperm extraction (TESE) in two groups of obstructive (n=10) and non-obstructive (n=10) azoospermic infertile men. Location of β-catenin accumulation was detected by immunofluorescence technic and quantitatively compared in the tissue followed by counterstaining with anti-vimentin antibody. It was used as specific marker of leydig cells to determine and confirm the cells in which this gathering was occurred.

RESULTS

β-catenin gene expression does not have a significant difference between the obstructive azoospermia (0.998) and non-obstructive azoospermia group (0.891). β-catenin was abnormally aggregated in leydig cell of non-obstructive azoospermic men.

CONCLUSION

Gathering β-catenin in cytoplasm of leydig cells can disrupt spermatogenesis and cause infertility in men.

SENP2 regulates MMP13 expression in a bladder cancer cell line through SUMOylation of TBL1/TBLR1

Bladder cancer (BC) is the most popular malignant urinary cancer in China. BC has the highest incidence and mortality among all genitourinary system tumors. Although the early-stage BC could be treated with advanced electron flexible systourethroscope, early metastasis of the BC occur frequently, and often results in poor prognosis. Recently, we reported that small ubiquitin related modifier (SUMO)-specific protease 2 (SENP2) was downregulated in BC specimen. SENP2 appeared to inhibit migration and invasion of bladder cancer cells in vitro, through suppressing MMP13 in BC cells. However, the exact underlying mechanisms remain unknown. Here, we reported that SENP2 inhibited nuclear translocation of β-catenin, which targeted the promotor of MMP13 to activate MMP13 to enhance BC cell metastasis. WNT ligands induced TBL1/TBLR1 SUMOylation to form complexes with β-catenin to facilitate β-catenin nuclear translocation, which could be efficiently inhibited through suppression of SUMOylation of TBL1/TBLR1. Together, our data suggest that SENP2 inhibits MMP13 expression in BC cells through de-SUMOylation of TBL1/TBLR1, which inhibits nuclear translocation of β-catenin. Thus, SENP2 may be a promising therapeutic target for BC.

Regulation of β-catenin transcription activity by leupaxin in hepatocellular carcinoma

In human cancers, β-catenin is accumulated in the nucleus and activates mRNA transcription of many oncogenic genes, such as cyclin D1 and c-myc. However, the mechanism of β-catenin-mediated transcriptional activation remains largely unknown. In the present study, we identified leupaxin, an adaptor protein sharing homology with the focal adhesion protein, as a novel coactivator for β-catenin in human hepatocellular carcinoma (HCC). We show that leupaxin could interact with β-catenin and enhance its transcriptional activity through recruitment of coactivator complex, including steroid receptor coactivator 1 (SRC-1) and P300. As a result, leupaxin regulates HCC cell proliferation and cell-cycle progression in the presence of intact Wnt/β-catenin signaling. Furthermore, leupaxin is overexpressed in HCC tissues and correlated with mRNA levels of cyclin D1 and c-myc. Therefore, this is the first demonstration of a role for the leupaxin in the regulation of HCC progression, at least in part, by enhancing β-catenin transcription activity.

Effect of curcumin on the interaction between androgen receptor and Wnt/β-catenin in LNCaP xenografts

Purpose

Curcumin is a nontoxic, chemopreventive agent possessing multifaceted functions. Our previous study showed that curcumin inhibits androgen receptor (AR) through modulation of Wnt/β-catenin signaling in LNCaP cells. Therefore, we investigated the in vivo effects of curcumin by using LNCaP xenografts.

Materials and Methods

LNCaP cells were subcutaneously inoculated in Balb/c nude mice. When the tumor volume reached greater than 100 mm³, either curcumin (500 mg/kg body weight) or vehicle was administered through oral gavage three times weekly for 4 weeks. The expression of AR and intermediate products of Wnt/β-catenin were assessed.

Results

Curcumin had an inhibitory effect on tumor growth during the early period, which was followed by a slow increase in growth over time. Tumor growth was delayed about 27% in the curcumin group. The mean prostate-specific antigen (PSA) doubling time in the curcumin group was approximately twice that in the untreated group. Curcumin significantly decreased AR expression at both the mRNA and protein level. The PSA levels tended to be reduced in the curcumin group. However, there were no significant changes in expression of Wnt/β-catenin pathway intermediates.

Conclusions

This study revealed that curcumin initially interferes with prostate cancer growth by inhibiting AR activity and possibly by reducing PSA expression. Further research is needed to investigate the plausible mechanism of the antiandrogenic action of curcumin.

Discovery of a novel epigenetic cancer marker related to the oxidative status of human blood

Long-lasting oxidative stress exposure may lead to relatively stable epigenetic modifications of the DNA in order to activate anti-oxidative defence mechanisms. Oxidative stress related DNA methylation may therefore be associated (causally or as a by-product) with cancer. We measured derivatives of reactive oxygen metabolites (D-ROM), total thiol levels (TTL) and DNA methylation with the Illumina Infinium 450K BeadChip in three samples of German individuals aged ≥50 years: n = 1,000 ESTHER study baseline participants (DNA methylation only), n = 99 ESTHER eight-year follow-up participants and n = 142 participants of the BLITZ study. The correlation coefficient of methylation at cg10342304 and D-ROM in the ESTHER 8-year follow-up sample (r = -0.427; P = 1 × 10(-5)) was replicated with a P-value indicating statistical significance after correction for multiple testing in the BLITZ sample (r = -0.192; P = 0.022). The association was robust to adjusting for potential confounders. In the ESTHER baseline sample, the hazard ratio for cancer development in 11 years of follow-up comparing bottom and top quartile of DNA methylation at cg10342304 was 1.86 (95%-confidence-interval 1.01-3.43). In summary, this first epigenome-wide screening and replication study with oxidative status markers observed a negative correlation of D-ROM levels and DNA methylation at cg10342304 in two independent cohorts. This CpG site is located in the body region of the nucleoredoxin gene. The nucleoredoxin protein is a redox-dependent inhibitor of the Wnt/ß-catenin signaling pathway, a well-characterized cancer pathway. If the observed CpG-cancer association can be successfully replicated by other studies, this epigenetic marker could be an interesting biomarker of cancer risk.

Androgen deprivation of prostate cancer: Leading to a therapeutic dead end

Androgen deprivation therapy (ADT) is considered as the standard therapy for men with de novo or recurrent metastatic prostate cancer. ADT commonly leads to initial biochemical and clinical responses. However, several months after the beginning of treatment, tumors become castration-resistant and virtually all patients show disease progression. At this stage, tumors are no longer curable and cancer treatment options are only palliative. In this review, we describe molecular alterations in tumor cells during ADT, which lead to deregulation of different signaling pathways and castration-resistance, and how they might interfere with the clinical outcome of different second-line therapeutics. A recent breakthrough finding that early chemotherapy is associated with a significant survival benefit in metastatic hormone-sensitive disease highlights the fact that there is time for a fundamental paradigm shift in the treatment of advanced prostate cancer. Therapeutic intervention seems to be indicated before a castration-resistant stage is reached to improve therapeutic outcome and to reduce undesirable side effects.

Telomerase reverse transcriptase potentially promotes the progression of oral squamous cell carcinoma through induction of epithelial-mesenchymal transition

In recent years, researchers have found the critical role of telomerase in cellular transformation, proliferation, stemness and cell survival. High levels of telomerase reverse transcriptase (TERT) expression and telomerase activation have been reported in most cancer cells. Moreover, overexpression of human TERT (hTERT) is reported to be correlated with advanced invasive stage of the tumor progression and poor prognosis. Epithelial-mesenchymal transition (EMT), characterized by the loss of the cell-cell contact of epithelial cells and the acquisition of migratory and motile properties, is known to be a central mechanism responsible for invasiveness and metastasis of various cancers. Thus, we investigated whether hTERT plays a potential role in the development of EMT. As we expected, our clinical results showed that hTERT is overexpressed in oral epithelial dysplasia (OED) and OSCC tissues and correlates with clinical aggressiveness of oral squamous cell carcinoma (OSCC) patients. We then overexpressed hTERT in primary human oral epithelial cells (HOECS) and found that hTERT has the potential to prolong the lifespan, a process confering the characteristics of EMT by activating the Wnt/β-catenin pathway. Our findings provided an explanation for the aggressive nature of human tumors overexpressing hTERT and the possibly mechanism that links hTERT to EMT property, which represents a possible therapeutic target in highly metastatic cancers.

The host microenvironment influences prostate cancer invasion, systemic spread, bone colonization, and osteoblastic metastasis

Prostate cancer (PCa) is the second leading cause of cancer death in men worldwide. Most PCa deaths are due to osteoblastic bone metastases. What triggers PCa metastasis to the bone and what causes osteoblastic lesions remain unanswered. A major contributor to PCa metastasis is the host microenvironment. Here, we address how the primary tumor microenvironment influences PCa metastasis via integrins, extracellular proteases, and transient epithelia-mesenchymal transition (EMT) to promote PCa progression, invasion, and metastasis. We discuss how the bone-microenvironment influences metastasis; where chemotactic cytokines favor bone homing, adhesion molecules promote colonization, and bone-derived signals induce osteoblastic lesions. Animal models that fully recapitulate human PCa progression from primary tumor to bone metastasis are needed to understand the PCa pathophysiology that leads to bone metastasis. Better delineation of the specific processes involved in PCa bone metastasize is needed to prevent or treat metastatic PCa. Therapeutic regimens that focus on the tumor microenvironment could add to the PCa pharmacopeia.

The systemic delivery of an oncolytic adenovirus expressing decorin inhibits bone metastasis in a mouse model of human prostate cancer

In an effort to develop a new therapy for prostate cancer bone metastases, we have created Ad.dcn, a recombinant oncolytic adenovirus carrying the human decorin gene. Infection of PC-3 and DU-145, the human prostate tumor cells, with Ad.dcn or a non-replicating adenovirus Ad(E1-).dcn resulted in decorin expression; Ad.dcn produced high viral titers and cytotoxicity in human prostate tumor cells. Adenoviral-mediated decorin expression inhibited Met, the Wnt/β-catenin signaling axis, vascular endothelial growth factor A, reduced mitochondrial DNA levels, and inhibited tumor cell migration. To examine the anti-tumor response of Ad.dcn, PC-3-luc cells were inoculated in the left heart ventricle to establish bone metastases in nude mice. Ad.dcn, in conjunction with control replicating and non-replicating vectors were injected via tail vein. The real-time monitoring of mice, once a week, by bioluminescence imaging and X-ray radiography showed that Ad.dcn produced significant inhibition of skeletal metastases. Analyses of the mice at the terminal time point indicated a significant reduction in the tumor burden, osteoclast number, serum TRACP 5b levels, osteocalcin levels, hypercalcemia, inhibition of cancer cachexia, and an increase in the animal survival. Based on these studies, we believe that Ad.dcn can be developed as a potential new therapy for prostate cancer bone metastasis.

Physiopathological aspects of the Wnt/β-catenin signaling pathway in the male reproductive system

The Wnt/β-catenin signaling pathway controls several biological processes throughout development and adult life. Dysregulation of Wnt/β-catenin signaling underlies a wide range of pathologies in animals and humans, including cancer in different tissues. In this review, we provide an update of the Wnt/β-catenin signaling pathway and the possible roles of the Wnt/β-catenin signaling in the biology of testis, epididymis and prostate. Data from our laboratory suggest the involvement of 17β-estradiol and estrogen receptors (ERs) on the regulation of β-catenin expression in rat Sertoli cells. We also provide emerging evidences of the involvement of Wnt/β-catenin pathway in testis and prostate cancer. Our understanding of the role of Wnt/β-Catenin signaling in male reproductive tissues is still evolving, and several questions are open to be addressed in the future.

TCF7L2 type 2 diabetes risk variant, lifestyle factors, and incidence of prostate cancer

BACKGROUND

Variation in transcription factor 7-like 2 (TCF7L2), the strongest genetic risk factor for type 2 diabetes (T2D), may play a role in prostate cancer (PCa) depending on lifestyle factors. The aims of this study were to determine if TCF7L2 rs7903146 is associated with risk of PCa and if the association is modified by lifestyle factors independently of T2D status.

METHODS

We prospectively followed 8,558 men in the Malmö Diet and Cancer Study from baseline 1991-1996 until end of 2009. Cox regression models were used to assess the association between rs7903146 T2D-risk allele (T) and PCa. Effect modification by incident T2D status, fasting glucose levels, dietary, and lifestyle risk factors were tested.

RESULTS

During follow-up 855 incident PCa cases were registered. We observed a non-significant tendency for the TCF7L2 variant to associate with higher risk of PCa, which was unaffected by adjustment for incident T2D (HR = 1.24; 95% CI: 0.96, 1.60; P = 0.079) but more pronounced among subjects who developed T2D (HR = 1.91, 95% CI: 0.88, 4.14; P = 0.064). In a sub-sample of hyperglycemic men we observed an increased risk of PCa among T-allele carriers (HR = 2.72, 95% CI: 1.22, 6.04; P = 0.014; P(interaction)  = 0.056). T-allele carriers with higher number of lifestyle risk factors had an increased risk of PCa (P(interaction)  = 0.006).

CONCLUSIONS

We found no independent association between TCF7L2 rs7903146 and PCa risk. However, among hyperglycemic men we observed that the risk allele may increase risk of PCa. The association between rs7903146 and PCa risk may also be modified by lifestyle factors.

Targeting the relaxin hormonal pathway in prostate cancer

Targeting the androgen signalling pathway has long been the hallmark of anti-hormonal therapy for prostate cancer. However, development of androgen-independent prostate cancer is an inevitable outcome to therapies targeting this pathway, in part, owing to the shift from cancer dependence on androgen signalling for growth in favor of augmentation of other cellular pathways that provide proliferation-, survival- and angiogenesis-promoting signals. This review focuses on the role of the hormone relaxin in the development and progression of prostate cancer, prior to and after the onset of androgen independence, as well as its role in cancers of other reproductive tissues. As the body of literature expands, examining relaxin expression in cancerous tissues and its role in a growing number of in vitro and in vivo cancer models, our understanding of the important involvement of this hormone in cancer biology is becoming clearer. Specifically, the pleiotropic functions of relaxin affecting cell growth, angiogenesis, blood flow, cell migration and extracellular matrix remodeling are examined in the context of cancer progression. The interactions and intercepts of the intracellular signalling pathways of relaxin with the androgen pathway are explored in the context of progression of castration-resistant and androgen-independent prostate cancers. We provide an overview of current anti-hormonal therapeutic treatment options for prostate cancer and delve into therapeutic approaches and development of agents aimed at specifically antagonizing relaxin signalling to curb tumor growth. We also discuss the rationale and challenges utilizing such agents as novel anti-hormonals in the clinic, and their potential to supplement current therapeutic modalities.

Transforming growth factor-β1 (TGF-β1) induces mouse precartilaginous stem cell proliferation through TGF-β receptor II (TGFRII)-Akt-β-catenin signaling

Precartilaginous stem cells (PSCs) could self-renew or differentiate into chondrocytes to promote bone growth. In the current study, we aim to understand the role of transforming growth factor-β1 (TGF-β1) in precartilaginous stem cell (PSC) proliferation, and to study the underlying mechanisms. We successfully purified and primary-cultured PSCs from the neonate mice’ perichondrial mesenchyme, and their phenotype was confirmed by the PSC marker fibroblast growth factor receptor-3 (FGFR-3) overexpression. We found that TGF-β1 induced Akt-glycogen synthase kinase-3β (GSK3β) phosphorylation and β-catenin nuclear translocation in the mouse PSCs, which was almost blocked by TGF-β receptor-II (TGFRII) shRNA knockdown. Further, perifosine and MK-2206, two Akt-specific inhibitors, suppressed TGF-β1-induced GSK3β phosphorylation and β-catenin nuclear translocation. Akt inhibitors, as well as β-catenin shRNA knockdown largely inhibited TGF-β1-stimulated cyclin D1/c-myc gene transcription and mouse PSC proliferation. Based on these results, we suggest that TGF-β1 induces Akt activation to promote β-catenin nuclear accumulation, which then regulates cyclin D1/c-myc gene transcription to eventually promote mouse PSC proliferation.

Anti-cancer activity of curcumin loaded nanoparticles in prostate cancer

Prostate cancer is the most commonly diagnosed cancer disease in men in the Unites States and its management remains a challenge in everyday oncology practice. Thus, advanced therapeutic strategies are required to treat prostate cancer patients. Curcumin (CUR) is a promising anticancer agent for various cancer types. The objective of this study was to evaluate therapeutic potential of novel poly(lactic-co-glycolic acid)- CUR nanoparticles (PLGA-CUR NPs) for prostate cancer treatment. Our results indicate that PLGA-CUR NPs efficiently internalize in prostate cancer cells and release biologically active CUR in cytosolic compartment of cells for effective therapeutic activity. Cell proliferation (MTS), clonogenic, and Western blot analyses reveal that PLGA-CUR NPs can effectively inhibit proliferation and colony formation ability of prostate cancer cells than free CUR. PLGA-CUR NPs showed superior tumor regression compared to CUR in xenograft mice. Further investigations reveal that PLGA-CUR NPs inhibit nuclear β-catenin and AR expression in cells and in tumor xenograft tissues. It also suppresses STAT3 and AKT phosphorylation and leads to apoptosis via inhibition of key anti-apoptotic proteins, Mcl-1, Bcl-xL and caused induction of PARP cleavage. Additionally, significant downregulation of oncogenic miR21 and up-regulation of miR-205 was observed with PLGA-CUR NPs treatment as determined by RT-PCR and in situ hybridization analyses. A superior anti-cancer potential was attained with PSMA antibody conjugated PLGA-CUR NPs in prostate cancer cells and a significant tumor targeting of (131)I labeled PSMA antibody was achieved with PLGA-CUR NPs in prostate cancer xenograft mice model. In conclusion, PLGA-CUR NPs can significantly accumulate and exhibit superior anticancer activity in prostate cancer.

Essential roles of epithelial bone morphogenetic protein signaling during prostatic development

Prostate is a male sex-accessory organ. The prostatic epithelia consist primarily of basal and luminal cells that differentiate from embryonic urogenital sinus epithelia. Prostate tumors are believed to originate in the basal and luminal cells. However, factors that promote normal epithelial differentiation have not been well elucidated, particularly for bone morphogenetic protein (Bmp) signaling. This study shows that Bmp signaling prominently increases during prostatic differentiation in the luminal epithelia, which is monitored by the expression of phosphorylated Smad1/5/8. To elucidate the mechanism of epithelial differentiation and the function of Bmp signaling during prostatic development, conditional male mutant mouse analysis for the epithelial-specific Bmp receptor 1a (Bmpr1a) was performed. We demonstrate that Bmp signaling is indispensable for luminal cell maturation, which regulates basal cell proliferation. Expression of the prostatic epithelial regulatory gene Nkx3.1 was significantly reduced in the Bmpr1a mutants. These results indicate that Bmp signaling is a key factor for prostatic epithelial differentiation, possibly by controlling the prostatic regulatory gene Nkx3.1.

Next-generation sequencing of advanced prostate cancer treated with androgen-deprivation therapy

BACKGROUND

Androgen-deprivation therapy (ADT) is standard treatment for locally advanced or metastatic prostate cancer (PCa). Many patients develop castration resistance (castration-resistant PCa [CRPC]) after approximately 2-3 yr, with a poor prognosis. The molecular mechanisms underlying CRPC progression are unclear.

OBJECTIVE

To undertake quantitative tumour transcriptome profiling prior to and following ADT to identify functionally important androgen-regulated pathways or genes that may be reactivated in CRPC.

DESIGN, SETTING, AND PARTICIPANTS

RNA sequencing (RNA-seq) was performed on tumour-rich, targeted prostatic biopsies from seven patients with locally advanced or metastatic PCa before and approximately 22 wk after ADT initiation. Differentially regulated genes were identified in treatment pairs and further investigated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) on cell lines and immunohistochemistry on a separate CRPC patient cohort. Functional assays were used to determine the effect of pathway modulation on cell phenotypes.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We searched for gene expression changes affecting key cell signalling pathways that may be targeted as proof of principle in a CRPC in vitro cell line model.

RESULTS AND LIMITATIONS

We identified ADT-regulated signalling pathways, including the Wnt/β-catenin signalling pathway, and observed overexpression of β-catenin in a subset of CRPC by immunohistochemistry. We validated 6 of 12 (50%) pathway members by qRT-PCR on LNCaP/LNCaP-AI cell RNAs, of which 4 (67%) demonstrated expression changes consistent with RNA-seq data. We show that the tankyrase inhibitor XAV939 (which promotes β-catenin degradation) reduced androgen-independent LNCaP-AI cell line growth compared with androgen-responsive LNCaP cells via an accumulation of cell proportions in the G0/G1 phase and reduction in the S and G2/M phases. Our biopsy protocol did not account for tumour heterogeneity, and pathway inhibition was limited to pharmacologic approaches.

CONCLUSIONS

RNA-seq of paired PCa samples revealed ADT-regulated signalling pathways. Proof-of-principle inhibition of the Wnt/β-catenin signalling pathway specifically delays androgen-independent PCa cell cycle progression and proliferation and warrants further investigation as a potential target for therapy for CRPC.

Expression of β-catenin and mesenchymal markers in canine prostatic hyperplasia and carcinoma

β-catenin is a nuclear signalling molecule that is associated with human prostatic neoplasia and the epithelial-mesenchymal transition (EMT) process. The present study evaluates immunohistochemically the expression of β-catenin and the mesenchymal markers vimentin, desmin, calponin and smooth muscle actin (SMA) in four normal canine prostates and prostate samples from 15 dogs with benign prostatic hyperplasia (BPH) and six with prostatic carcinoma (PC). β-catenin was located on the membrane of normal epithelial cells, while the same marker had both cytoplasmic and membrane expression in hyperplastic cells and a nuclear redistribution in PC. Vimentin-positive luminal cells were observed in two of the 15 cases of BPH and in all PC samples, suggesting the conversion of neoplastic epithelial cells to a mesenchymal type. SMA was consistently negative in PC, but there was mild desmin and calponin immunoreactivity in these lesions. As in men, β-catenin is involved in canine prostatic carcinogenesis, thus further validating the use of this animal model to study human prostatic disease.