WISP-2 gene in human breast cancer: estrogen and progesterone inducible expression and regulation of tumor cell proliferation

hnRNPA1 promotes the metastasis and proliferation of gastric cancer cells through WISP2-guided Wnt/β-catenin signaling pathway

The main cause of gastric cancer (GC)-related death is due to malignant cell unregulated distant metastasis and proliferation. Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) has been shown to play an important role in carcinogenesis and the development of metastasis in several tumors. However, its downstream regulatory mechanism in GC is not well defined. Our study aims to investigate the function and regulatory mechanism of hnRNPA1 in GC. We analyzed the differential expression of hnRNPA1 in gastric cancer and paired adjacent normal tissues in the TCGA database. Kaplan-Meier analysis was employed for survival assessment. The expressions of hnRNPA1 in GC cells were measured by qRT-PCR and Western blot. Transwell assay, CCK8 and colony formation assay were used to detect the effect of hnRNPA1 on the metastasis and proliferation ability of GC cells. Additionally, Western blotting was performed to examine the expression of proteins related to the Wnt/β-catenin signaling pathway as well as epithelial-mesenchymal transition (EMT), while further investigations were carried out to explore potential regulatory mechanisms. The results showed that hnRNPA1 was highly expressed differentially in GC over normal gastric tissue. Knocking down hnRNPA1 inhibited the metastasis and proliferation of human gastric cancer cells. Overexpression of hnRNPA1 significantly enhanced the metastatic potential and proliferative capacity of human GC cells. Further mechanism exploration revealed that knocking down hnRNPA1 inhibited the Wnt/β-catenin signaling pathway and WNT1 inducible signaling pathway protein-2 (WISP2), an activator of the Wnt/β-catenin signaling pathway. Whereas overexpression of hnRNPA1 had the opposite effects. Our results demonstrated that hnRNPA1 promoted metastasis and proliferation of GC cells by activating Wnt/β-catenin signaling pathway via WISP2. hnRNPA1 may serve as a potential biomarker and novel therapeutic targets for GC.

A Meta-analysis of Transcriptome Data to Investigate the Effect of Soy Isoflavones on Breast Cancer Cell

Background

Breast cancer ranks as the second highest cause of cancer-linked deaths in women, with varying rates between Western and Asian countries. The consumption of phytoestrogens can influence breast cancer occurrence.

Objective

To comprehend how soy isoflavones impact breast cancer cells, we conducted a meta-analysis, combining gene expression data from multiple studies. This approach aimed to identify crucial transcriptional characteristics driving breast cancer cell response to soy phytoestrogens.

Materials and Methods

The gene expression profiles obtained from the Gene Expression Omnibus and Array Express and were grouped into control and isoflavones exposure conditions. We performed a meta-analysis based on the effect size combination method to identify the differentially expressed genes (DEGs). In addition, we performed Gene Ontology (GO) enrichment analysis, pathway analysis, weighted gene co-expression network analysis (WGCNA) and recursive support vector machine (R-SVM) algorithm.

Results

Based on this meta-analysis, we identified 3,890 DEGs, of which 2,173 were up-regulated and 1,717 were down-regulated. For example, SGCG, PLK2, and TBC1D9 were the most highly down-regulated genes and EGR3, WISP2, and FKBP4 were the most highly expressed genes in the isoflavones exposure condition. The functional enrichment and pathway analysis were revealed "cell division" and "cell cycle" among the most enriched terms. Among the identified DEGs, 269 transcription factor (TF) genes belonged to 42 TF families, where the C2H2 ZF, bZIP, and bHLH were the most prominent families. We also employed the R-SVM for detecting the most important genes to classify samples into isoflavones exposure and control conditions. It identified a subset of 100 DEGs related to regulation of cell growth, response to estradiol, and intermediate ribonucleoside monophosphate in the purine (IMP) metabolic process. Moreover, the WGCNA separated the DEGs into five discrete modules strongly enriched for genes involved in cell division, DNA replication, embryonic digit morphogenesis, and cell-cell adhesion.

Conclusion

Our analysis provides evidence suggesting that isoflavone affects various mechanisms in cells, including pathways associated with NF-κB, Akt, MAPK, Wnt, Notch, p53, and AR pathways, which can lead to the induction of apoptosis, the alteration of the cell cycle, the inhibition of angiogenesis, and interference in the redox state of cells. These findings can shed light on the molecular mechanisms that underlie the response of breast cancer cells to isoflavones.

The role of CCNs in controlling cellular communication in the tumor microenvironment

The Cellular communication network (CCN) family of growth regulatory factors comprises six secreted matricellular proteins that promote signal transduction through cell-cell or cell-matrix interaction. The diversity of functionality between each protein is specific to the many aspects of healthy and cancer biology. For example, CCN family proteins modulate cell adhesion, proliferation, migration, invasiveness, apoptosis, and survival. In addition, the expression of each protein regulates many biological and pathobiological processes within its microenvironment to regulate angiogenesis, inflammatory response, chondrogenesis, fibrosis, and mitochondrial integrity. The collective range of CCN operation remains fully comprehended; however, understanding each protein's microenvironment may draw more conclusions about the abundance of interactions and signaling cascades occurring within such issues. This review observes and distinguishes the various roles a CCN protein may execute within distinct tumor microenvironments and the biological associations among them. Finally. We also review how CCN-family proteins can be used in nano-based therapeutic implications.

Acetylation stabilizes the signaling protein WISP2 by preventing its degradation to suppress the progression of acute myeloid leukemia

Acute myeloid leukemia (AML) is challenging to treat due to its heterogeneity, prompting a deep understanding of its pathogenesis mechanisms, diagnosis, and treatment. Here, we found reduced expression and acetylation levels of WISP2 in bone marrow mononuclear cells from AML patients and that AML patients with lower WISP2 expression tended to have reduced survival. At the functional level, overexpression of WISP2 in leukemia cells (HL-60 and Kasumi-1) suppressed cell proliferation, induced cell apoptosis, and exerted antileukemic effects in an in vivo model of AML. Our mechanistic investigation demonstrated that WISP2 deacetylation was regulated by the deacetylase histone deacetylase (HDAC)3. In addition, we determined that crosstalk between acetylation and ubiquitination was involved in the modulation of WISP2 expression in AML. Deacetylation of WISP2 decreased the stability of the WISP2 protein by boosting its ubiquitination mediated by NEDD4 and proteasomal degradation. Moreover, pan-HDAC inhibitors (valproic acid and trichostatin A) and an HDAC3-specific inhibitor (RGFP966) induced WISP2 acetylation at lysine K6 and prevented WISP2 degradation. This regulation led to inhibition of proliferation and induction of apoptosis in AML cells. In summary, our study revealed that WISP2 contributes to tumor suppression in AML, which provided an experimental framework for WISP2 as a candidate for gene therapy of AML.

Tissue distribution and transcriptional regulation of CCN5 in the heart after myocardial infarction

CCN5 is a divergent member of the cellular communication network factor (CCN) family in that it lacks the carboxyl terminal cystine knot domain common to the other CCN family members. CCN5 has been reported to antagonize the profibrotic actions of CCN2 and to inhibit myocardial collagen deposition and fibrosis in chronic pressure overload of the heart. However, what mechanisms that regulate CCN5 activity in the heart remain unknown. Recombinant, replication defective adenovirus encoding firefly luciferase under control of the human CCN5 promoter was prepared and used to investigate what mechanisms regulate CCN5 transcription in relevant cells. Tissue distribution of CCN5 in hearts from healthy mice and from mice subjected to myocardial infarction was investigated. Contrary to the profibrotic immediate early gene CCN2, we find that CCN5 is induced in the late proliferation and maturation phases of scar healing. CCN5 was identified principally in endothelial cells, fibroblasts, smooth muscle cells, and macrophages. Our data show that CCN5 gene transcription and protein levels are induced by catecholamines via β₂-adrenergic receptors. Myocardial induction of CCN5 was further confirmed in isoproterenol-infused mice. We also find that CCN5 transcription is repressed by TNF-α, an inflammatory mediator highly elevated in early phases of wound healing following myocardial infarction. In conclusion, CCN5 predominates in endothelial cells, fibroblasts, and macrophages of the differentiating scar tissue and its transcription is conversely regulated by β₂-adrenergic agonists and TNF-α.

CCN Family Proteins in Cancer: Insight Into Their Structures and Coordination Role in Tumor Microenvironment

The crosstalk between tumor cells and the tumor microenvironment (TME), triggers a variety of critical signaling pathways and promotes the malignant progression of cancer. The success rate of cancer therapy through targeting single molecule of this crosstalk may be extremely low, whereas co-targeting multiple components could be complicated design and likely to have more side effects. The six members of cellular communication network (CCN) family proteins are scaffolding proteins that may govern the TME, and several studies have shown targeted therapy of CCN family proteins may be effective for the treatment of cancer. CCN protein family shares similar structures, and they mutually reinforce and neutralize each other to serve various roles that are tightly regulated in a spatiotemporal manner by the TME. Here, we review the current knowledge on the structures and roles of CCN proteins in different types of cancer. We also analyze CCN mRNA expression, and reasons for its diverse relationship to prognosis in different cancers. In this review, we conclude that the discrepant functions of CCN proteins in different types of cancer are attributed to diverse TME and CCN truncated isoforms, and speculate that targeting CCN proteins to rebalance the TME could be a potent anti-cancer strategy.

CCN5 inhibits proliferation and promotes apoptosis of oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) is a common cancer with poor prognosis and high mortality. The role of CCN5 has attracted a great focus on the regulation of cancer progression. However, the biological function and mechanism of CCN5 in OSCC are still not well elucidated. The current study was designed to determine the effects of CCN5 on OSCC cell proliferation and apoptosis using two OSCC cell lines. Further, LY294002, a PI3K/AKT antagonist, was employed to explore the mechanism underlying the effects of CCN5 in the regulation of OSCC. The results showed that overexpression of CCN5 in TSCCa cells significantly reduced viable cell number, arrested cell cycle, and suppressed cell-cycle regulators (cyclin D1, cyclin E, and CDK2). CCN5 overexpression increased the apoptotic ratio and Hoechst-positive cell number, and altered the apoptotic-related proteins (caspase-3/9, Bax, and Bcl-2). However, CCN5 silencing induced opposite effects on cell proliferation and apoptosis in Tca-8113 cells. In addition, we observed that CCN5 knockdown increased the expression levels of PI3K (p85α and p110α) and phosphorylated AKT at serine 473 (p-AKT Ser473) in Tca-8113 cells. Inhibiting PI3K/AKT signaling with LY294002 rescued the apoptotic process in CCN5-silenced OSCC cells. Finally, xenograft analysis showed that CCN5 represses tumorigenesis of OSCC cells. These findings together suggest that CCN5 functions as a tumor suppressor for OSCC cell development through inactivation of PI3K/AKT signaling pathway, providing a potential candidate for OSCC therapy.

Recombinant protein CCN5/WISP2 promotes islet cell proliferation and survival in vitro

Pancreatic ß cell proliferation, survival and function are key elements that need to be considered in developing novel antidiabetic therapies. We recently identified CCN5/WISP2 to have potential growth promoting properties when overexpressed in ß cells; however, further investigations are needed to validate those properties. In this study, we demonstrated that exogenous treatment of insulinoma cells and primary islets with recombinant CCN5 (rh-CCN5) protein enhanced the proliferative capacity which was correlated with activation of cell-cycle regulators CDK4 and cyclin D1. Furthermore, pre-incubation of these cells with rh-CCN5 enhanced their survival rate after being exposed to harsh treatments such as streptozotocin and high concentrations of glucose and free fatty acids. CCN5 as well caused an upregulation in the expression of key genes associated with ß cell identity and function such as GLUT-2 and GCK. Finally, CCN5 activated FAK and downstream ERK kinases which are known to stimulate cell proliferation and survival. Hence, our results validate the growth promoting activities of rh-CCN5 in ß cells and open the door for further investigations in vivo.

Secreted frizzled-related protein 2 (SFRP2) expression promotes lesion proliferation via canonical WNT signaling and indicates lesion borders in extraovarian endometriosis

STUDY QUESTION

What is the role of SFRP2 in endometriosis?

SUMMARY ANSWER

SFRP2 acts as a canonical WNT/CTNNB1 signaling agonist in endometriosis, regulating endometriosis lesion growth and indicating endometriosis lesion borders together with CTNNB1 (also known as beta catenin).

WHAT IS KNOWN ALREADY

Endometriosis is a common, chronic disease that affects women of reproductive age, causing pain and infertility, and has significant economic impact on national health systems. Despite extensive research, the pathogenesis of endometriosis is poorly understood, and targeted medical treatments are lacking. WNT signaling is dysregulated in various human diseases, but its role in extraovarian endometriosis has not been fully elucidated.

STUDY DESIGN, SIZE, DURATION

We evaluated the significance of WNT signaling, and especially secreted frizzled-related protein 2 (SFRP2), in extraovarian endometriosis, including peritoneal and deep lesions. The study design was based on a cohort of clinical samples collected by laparoscopy or curettage and questionnaire data from healthy controls and endometriosis patients.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Global gene expression analysis in human endometrium (n = 104) and endometriosis (n = 177) specimens from 47 healthy controls and 103 endometriosis patients was followed by bioinformatics and supportive qPCR analyses. Immunohistochemistry, Western blotting, primary cell culture and siRNA knockdown approaches were used to validate the findings.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the 220 WNT signaling and CTNNB1 target genes analysed, 184 genes showed differential expression in extraovarian endometriosis (P < 0.05) compared with endometrium tissue, including SFRP2 and CTNNB1. Menstrual cycle-dependent regulation of WNT genes observed in the endometrium was lost in endometriosis lesions, as shown by hierarchical clustering. Immunohistochemical analysis indicated that SFRP2 and CTNNB1 are novel endometriosis lesion border markers, complementing immunostaining for the known marker CD10 (also known as MME). SFRP2 and CTNNB1 localized similarly in both the epithelium and stroma of extraovarian endometriosis tissue, and interestingly, both also indicated an additional distant lesion border, suggesting that WNT signaling is altered in the endometriosis stroma beyond the primary border indicated by the known marker CD10. SFRP2 expression was positively associated with pain symptoms experienced by patients (P < 0.05), and functional loss of SFRP2 in extraovarian endometriosis primary cell cultures resulted in decreased cell proliferation (P < 0.05) associated with reduced CTNNB1 protein expression (P = 0.05).

LIMITATIONS REASONS FOR CAUTION

SFRP2 and CTNNB1 improved extraovarian endometriosis lesion border detection in a relatively small cohort (n = 20), although larger studies with different endometriosis subtypes in variable cycle phases and under hormonal medication are required.

WIDER IMPLICATIONS OF THE FINDINGS

The highly expressed SFRP2 and CTNNB1 improve endometriosis lesion border detection, which can have clinical implications for better visualization of endometriosis lesions over CD10. Furthermore, SFRP2 acts as a canonical WNT/CTNNB1 signaling agonist in endometriosis and positively regulates endometriosis lesion growth, suggesting that the WNT pathway may be an important therapeutic target for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Academy of Finland and by Tekes: Finnish Funding Agency for Innovation. The authors have no conflict of interest to declare.

The emerging role of WISP proteins in tumorigenesis and cancer therapy

Accumulated evidence has demonstrated that WNT1 inducible signaling pathway protein (WISP) genes, which belong to members of the CCN growth factor family, play a pivotal role in tumorigenesis and progression of a broad spectrum of human cancers. Mounting studies have identified that WISP proteins (WISP1-3) exert different biological functions in various human malignancies. Emerging evidence indicates that WISP proteins are critically involved in cell proliferation, apoptosis, invasion and metastasis in cancers. Because the understanding of a direct function of WISP proteins in cancer development and progression has begun to emerge, in this review article, we describe the physiological function of WISP proteins in a variety of human cancers. Moreover, we highlight the current understanding of how the WISP protein is involved in tumorigenesis and cancer progression. Furthermore, we discuss that targeting WISP proteins could be a promising strategy for the treatment of human cancers. Hence, the regulation of WISP proteins could improve treatments for cancer patients.

Leptin-induced ER-α-positive breast cancer cell viability and migration is mediated by suppressing CCN5-signaling via activating JAK/AKT/STAT-pathway

Background

In menopausal women, one of the critical risk factors for breast cancer is obesity/adiposity. It is evident from various studies that leptin, a 16 kDa protein hormone overproduced in obese people, plays the critical role in neovascularization and tumorigenesis in breast and other organs. However, the mechanisms by which obesity influences the breast carcinogenesis remained unclear. In this study, by analyzing different estrogen receptor-α (ER-α)-positive and ER-α-negative BC cell lines, we defined the role of CCN5 in the leptin-mediated regulation of growth and invasive capacity.

Methods

We analyzed the effect of leptin on cell viability of ER-α-positive MCF-7 and ZR-75-1 cell lines and ER-α-negative MDA-MB-231 cell line. Additionally, we also determined the effect of leptin on the epithelial-mesenchymal transition (EMT) bio-markers, in vitro invasion and sphere-formation of MCF-7 and ZR-75-1 cell lines. To understand the mechanism, we determined the impact of leptin on CCN5 expression and the functional role of CCN5 in these cells by the treatment of human recombinant CCN5 protein(hrCCN5). Moreover, we also determined the role of JAK-STAT and AKT in the regulation of leptin-induced suppression of CCN5 in BC cells.

Results

Present studies demonstrate that leptin can induce cell viability, EMT, sphere-forming ability and migration of MCF-7 and ZR-75-1 cell lines. Furthermore, these studies found that leptin suppresses the expression of CCN5 at the transcriptional level. Although the CCN5 suppression has no impact on the constitutive proliferation of MCF-7 and ZR-75-1 cells, it is critical for leptin-induced viability and necessary for EMT, induction of in vitro migration and sphere formation, as the hrCCN5 treatment significantly inhibits the leptin-induced viability, EMT, migration and sphere-forming ability of these cells. Mechanistically, CCN5-suppression by leptin is mediated via activating JAK/AKT/STAT-signaling pathways.

Conclusions

These studies suggest that CCN5 serves as a gatekeeper for leptin-dependent growth and progression of luminal-type (ER-positive) BC cells. Leptin may thus need to destroy the CCN5-barrier to promote BC growth and progression via activating JAK/AKT/STAT signaling. Therefore, these observations suggest a therapeutic potency of CCN5 by restoration or treatment in obese-related luminal-type BC growth and progression.

Estrogen-dependent downregulation of hypoxia-inducible factor (HIF)-2α in invasive breast cancer cells

The involvement of estrogen (E2) and hypoxia in tumor progression is well established. Hypoxia has been reported to activate and degrade estrogen receptor alpha (ERα) in breast cancer cells. Furthermore, E2 has been shown to regulate hypoxia-inducible factor (HIF)-1α protein, but its role in HIF-2α regulation remains largely unexplored. In this study, we found that both HIF-2α mRNA and protein were down-regulated in ER positive but not ER negative breast cancer cells upon treatment with E2. The analysis of 690 samples derived from 608 mixed and 82 triple-negative breast cancer patients revealed that high nuclear HIF-2α tumor levels are associated with a worse prognosis specifically in human epidermal growth factor receptor 2 (HER2) and hormone receptor positive patients. Consistently, ERα/HER2 positive breast cancer cells displayed less pronounced downregulation of HIF-2α by E2. Experiments using a histone deacetylase inhibitor indicate that the E2 mediated decrease in HIF-2α mRNA is due to transcriptional repression. A functional estrogen response element (ERE) was identified in the first intron of the gene encoding HIF-2α (EPAS1), suggesting transcriptional co-repressor recruitment by ERα. Our results demonstrate a novel modulation of HIF-2α in breast cancer cells, explaining the opposing regulation between HIF-1α and HIF-2α in hormone-responsive breast cancer.

Detection of CCN1 and CCN5 mRNA in Human Cancer Samples Using a Modified In Situ Hybridization Technique

In situ hybridization is an ideal tool for the detection and localization of mRNA expression of specific gene(s) in tissue sections and cell lines for prognosis, predictive markers, and highlighted potential therapeutic targets. Given the importance of CCN1 and CCN5 in breast and pancreatic cancer progression, these two secretory proteins could be novel therapeutic targets. Thus, evaluating the distribution of mRNA of these targets using in situ hybridization could be important preclinical tools. This chapter describes a detailed in situ hybridization technique for the detection of CCN1 and CCN5 in formalin-fixed, paraffin-embedded patient samples of breast and pancreatic cancers.

Wisp2 disruption represses Cxcr4 expression and inhibits BMSCs homing to injured liver

Liver regeneration/repair is a compensatory regrowth following acute liver failure, and bone marrow-derived mesenchyme stem cell (BMSC) transplantation is an effective therapy that promotes liver regeneration/repair. Wnt1 inducible signaling pathway protein 2 (Wisp2) is highly expressed in BMSCs, however, its function remains unclear. In this work, we used clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein -9 nuclease (CRISPR/Cas9) genome editing technology to knockdown Wisp2 in BMSCs, and these modified cells were then transplanted into rats which were induced by the 2-AAF/PH. By linking the expression of Cas9 to green fluorescent protein (GFP), we tracked BMSCs in the rats. Disruption of Wisp2 inhibited the homing of BMSCs to injured liver and aggravated liver damage as indicated by remarkably high levels of ALT and AST. Moreover, the key factor in BMSC transplantation, C-X-C chemokine receptor type 4 (Cxcr4), was down-regulated in the Wisp2 depleted BMSCs and had a lower expression in the livers of the corresponding rats. By tracing the GFP marker, more BMSCs were observed to differentiate into CD31 positive endothelial cells in the functional Wisp2 cells but less in the Wisp2 gene disrupted cells. In summary, Wisp2 promotes the homing of BMSCs through Cxcr4 related signaling during liver repair in rats.

Genome-wide RNA-Sequencing analysis identifies a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery

Fibrosis-related events play a part in most blinding diseases worldwide. However, little is known about the mechanisms driving this complex multifactorial disease. Here we have carried out the first genome-wide RNA-Sequencing study in human conjunctival fibrosis. We isolated 10 primary fibrotic and 7 non-fibrotic conjunctival fibroblast cell lines from patients with and without previous glaucoma surgery, respectively. The patients were matched for ethnicity and age. We identified 246 genes that were differentially expressed by over two-fold and p < 0.05, of which 46 genes were upregulated and 200 genes were downregulated in the fibrotic cell lines compared to the non-fibrotic cell lines. We also carried out detailed gene ontology, KEGG, disease association, pathway commons, WikiPathways and protein network analyses, and identified distinct pathways linked to smooth muscle contraction, inflammatory cytokines, immune mediators, extracellular matrix proteins and oncogene expression. We further validated 11 genes that were highly upregulated or downregulated using real-time quantitative PCR and found a strong correlation between the RNA-Seq and qPCR results. Our study demonstrates that there is a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery and provides new insights into the mechanistic pathways driving the complex fibrotic process in the eye and other tissues.

CCN5/WISP-2 restores ER-∝ in normal and neoplastic breast cells and sensitizes triple negative breast cancer cells to tamoxifen

CCN5/WISP-2 is an anti-invasive molecule and prevents breast cancer (BC) progression. However, it is not well understood how CCN5 prevents invasive phenotypes of BC cells. CCN5 protein expression is detected in estrogen receptor-α (ER-α) -positive normal breast epithelial cells as well as BC cells, which are weakly invasive and rarely metastasize depending on the functional status of ER-α. A unique molecular relation between CCN5 and ER-α has been established as the components of the same signaling pathway that coordinate some essential signals associated with the proliferation as well as delaying the disease progression from a non-invasive to invasive phenotypes. Given the importance of this connection, we determined the role of CCN5 in regulation of ER-α in different cellular settings and their functional relationship. In a genetically engineered mouse model, induced expression of CCN5 in the mammary ductal epithelial cells by doxycycline promotes ER-α expression. Similarly, CCN5 regulates ER-α expression and activity in normal and neoplastic breast cells, as documented in various in vitro settings such as mouse mammary gland culture, human mammary epithelial cell and different BC cell cultures in the presence or absence of human recombinant CCN5 (hrCCN5) protein. Mechanistically, at least in the BC cells, CCN5 is sufficient to induce ER-α expression at the transcription level via interacting with integrins-α6β1 and suppressing Akt followed by activation of FOXO3a. Moreover, in vitro and in vivo functional assays indicate that CCN5 treatment promotes response to tamoxifen in triple-negative BC (TNBC) cells possibly via restoring ER-α. Collectively, these studies implicates that the combination treatments of CCN5 (via activation of CCN5 or hrCCN5 treatment) and tamoxifen as potential therapies for TNBC.

Role of CCN5 (WNT1 inducible signaling pathway protein 2) in pancreatic islets

In search of direct targets of insulin-like growth factor (IGF)-1 action, we discovered CCN5 (WNT1 inducible signaling pathway protein 2 [WISP2]) as a novel protein expressed in pancreatic β-cells. As a member of the "CCN" ( C ysteine-rich angiogenic inducer 61 [Cyr61], C onnective tissue growth factor [CTGF in humans], and N ephroblastoma overexpressed [Nov; in chickens]) family, the expression of CCN5/WISP2 is stimulated by IGF-1 together with Wnt signaling. When overexpressed in insulinoma cells, CCN5 promotes cell proliferation and cell survival against streptozotocin-induced cell death. The cell proliferation effect seems to be caused by AKT phosphorylation and increased cyclin D1 levels. These properties resemble those of CCN2/CTGF, another isoform of the CCN family, although CCN5 is the only one within the family of six proteins that lacks the C-terminal repeat. Treatment of primary mouse islets with recombinant CCN5 protein produced similar effects to those of gene transfection, indicating that either as a matricellular protein or a secreted growth factor, CCN5 stimulates β-cell proliferation and regeneration in a paracrine fashion. This review also discusses the regulation of CCN5/WISP2 by estrogen and its involvement in angiogenesis and tumorigenesis.

Regulation of the CCN genes by vitamin D: A possible adjuvant therapy in the treatment of cancer and fibrosis

The CCN family is composed of six cysteine-rich, modular, and conserved proteins whose functions span a variety of tissues and include cell proliferation, adhesion, angiogenesis, and wound healing. Roles for the CCN proteins throughout the entire body including the skin, kidney, brain, blood vessels, hematopoietic compartment and others, are continuously being elucidated. Likewise, an understanding of the regulation of this important gene family is constantly becoming clearer, through identification of transcription factors that directly activate, repress, or respond to upstream cell signaling pathways, as well as other forms of gene expression control. Vitamin D (1,25-dihydroxyvitamin D3 or calcitriol), a vitamin essential for numerous biological processes, acts as a potent gene expression modulator. The regulation of the CCN gene family members by calcitriol has been described in many contexts. Here, we provide a concise and thorough overview of what is known about calcitriol and its regulation of the CCN genes, and argue that its regulation is of physiological importance in a wide breadth of tissues in which CCN genes function. In addition, we highlight the effects of vitamin D on CCN gene expression in the setting of two common pathologic conditions, fibrosis and cancer, and propose that the therapeutic effects of vitamin D3 described in these disease states may in part be attributable to CCN gene modulation. As vitamin D is perfectly safe in a wide range of doses and already showing promise as an adjuvant therapeutic agent, a deeper understanding of its control of CCN gene expression may have profound implications in clinical management of disease.

Flaxseed and its components differentially affect estrogen targets in pre-neoplastic hen ovaries

Flaxseed has been studied for decades for its health benefits that include anti-cancer, cardio-protective, anti-diabetic, anti-inflammatory properties. The biologically active components that mediate these effects are the omega-3 fatty acids and the lignan, secoisolariciresinol diglucoside. We have previously shown that whole flaxseed supplemented diet decreases the severity and incidence of ovarian cancer while a 15% dose of flaxseed is most protective against inflammation and estrogen-induced chemical and genotoxicity. The objective of this study was to dissect the independent effects of the two flaxseed components on estrogen signaling and metabolism. Two and half year old hens were fed either a control diet, 15% whole flaxseed diet, defatted flax meal diet or 5% flax oil diet for 3 months after which the animals were sacrificed and blood and tissues were harvested. Whole flaxseed diet caused a decrease in expression of ERα. ERα target gene expression was assessed using RT(2) profiler PCR array. Some targets involved in the IGF/insulin signaling pathway (IRS1, IGFBP4, IGFBP5) were downregulated by flaxseed and its components. Flaxseed diet also downregulated AKT expression. A number of targets related to NF-kB signaling were altered by flaxseed diet including a series of targets implicated in cancer. Whole flaxseed diet also affected E2 metabolism by increasing CYP1A1 expression with a corresponding increase in the onco-protective E2 metabolite, 2-methoxyestradiol. The weak anti-estrogens, enterolactone, enterodiol and 2-methoxyestradiol, might be working synergistically to generate a protective effect on the ovaries from hens on whole flaxseed diet by altering the estrogen signaling and metabolism.

WISP-2 in human gastric cancer and its potential metastatic suppressor role in gastric cancer cells mediated by JNK and PLC-γ pathways

BACKGROUND

It has recently been shown that WISP proteins (Wnt-inducted secreted proteins), a group of intra- and extra-cellular regulatory proteins, have been implicated in the initiation and progression of a variety of tumour types including colorectal and breast cancer. However, the role of WISP proteins in gastric cancer (GC) cells and their clinical implications have not yet been elucidated.

METHODS

The expression of WISP molecules in a cohort of GC patients was analysed using real-time quantitative PCR and immunohistochemistry. The expression of a panel of recognised epithelial-mesenchymal transition (EMT) markers was quantified using Q-PCR in paired tumour and normal tissues. WISP-2 knockdown (kd) sublines using ribozyme transgenes were created in the GC cell lines AGS and HGC27. Subsequently, several biological functions, including cell growth, adhesion, migration and invasion, were studied. Potential pathways for the interaction of EMT, extracellular matrix and MMP were evaluated.

RESULTS

Overexpression of WISP-2 was detected in GC and significantly correlated with early tumour node-metastasis staging, differentiation status and positively correlated with overall survival and disease-free survival of the patients. WISP-2 expression was inversely correlated with that of Twist and Slug in paired samples. Kd of WISP-2 expression promoted the proliferation, migration and invasion of GC cells. WISP-2 suppressed GC cell metastasis through reversing EMT and suppressing the expression and activity of MMP9 and MMP2 via JNK and ERK. Cell motility analysis indicated that WISP-2 kd contributed to GC cells' motility and can be attenuated by PLC-γ and JNK small inhibitors.

CONCLUSIONS

Increased expression of WISP-2 in GC is positively correlated with favourable clinical features and the survival of patients with GC and is a negative regulator of growth, migration and invasion in GC cells. These findings suggest that WISP-2 is a potential tumour suppressor in GC.

The expression of Wnt-1 inducible signaling pathway protein-2 in astrocytoma: Correlation between pathological grade and clinical outcome

Wnt-1 inducible signaling pathway protein-2 (WISP-2) is a member of the CCN family, which is critical for the control of cell morphology, motion, adhesion and other processes involved in tumorigenesis. The expression pattern and clinical significance of WISP-2 in astrocytomas remains unclear. In this study, reverse transcription-polymerase chain reaction was performed to systematically investigate the expression of WISP-2 in 47 astrocytoma tissues of different pathological grades and 10 normal brain tissues. The mRNA expression levels of WISP-2 in the astrocytoma tissues were observed to be significantly higher than those in the normal brain tissues. Furthermore, the upregulation of WISP-2 was found to be associated with astrocytomas of higher pathological grades. Subsequently, 154 astrocytoma and 15 normal brain tissues were analyzed using immunohistochemistry and similar results were obtained. Univariate and multivariate survival analyses were used to determine the correlations between WISP-2 expression and overall survival (OS) and progression-free survival (PFS). The results indicated that the expression of WISP-2 was found to negatively correlate with patient PFS and OS. These results demonstrated that the WISP-2 protein is involved in the pathogenesis and progression of human astrocytomas and may serve as a malignant biomarker of this disease.

CCN5/WISP-2 promotes growth arrest of triple-negative breast cancer cells through accumulation and trafficking of p27(Kip1) via Skp2 and FOXO3a regulation

The matricellular protein CCN5/WISP-2 represents a promising target in triple-negative breast cancer (TNBC) because treatment or induced activation of CCN5 in TNBC cells promotes cell growth arrest at the G0/G1 phase, reduces cell proliferation and delays tumor growth in the xenograft model. Our studies found that the p27(Kip1) tumor suppressor protein is upregulated and relocalized to the nucleus from cytoplasm by CCN5 in these cells and that these two events (upregulation and relocalization of p27(Kip1)) are critical for CCN5-induced growth inhibition of TNBC cells. In the absence of CCN5, p27(Kip1) resides mostly in the cytoplasm, which is associated with the aggressive nature of cancer cells. Mechanistically, CCN5 inhibits Skp2 expression, which seems to stabilize the p27(Kip1) protein in these cells. On the other hand, CCN5 also recruits FOXO3a to mediate the transcriptional regulation of p27(Kip1). The recruitment of FOXO3a is achieved by the induction of its expression and activity through shifting from cytoplasm to the nucleus. Our data indicate that CCN5 blocks PI3K/AKT signaling to dephosphorylate at S318, S253 and Thr32 in FOXO3a for nuclear relocalization and activation of FOXO3a. Moreover, inhibition of α6β1 receptors diminishes CCN5 action on p27(Kip1) in TNBC cells. Collectively, these data suggest that CCN5 effectively inhibits TNBC growth through the accumulation and trafficking of p27(Kip1) via Skp2 and FOXO3a regulation, and thus, activation of CCN5 may have the therapeutic potential to kill TNBC.

Targeting WNT1-inducible signaling pathway protein 2 alters human breast cancer cell susceptibility to specific lysis through regulation of KLF-4 and miR-7 expression

The molecular basis for the resistance of tumor cells to cell-mediated cytotoxicity remains poorly understood and thus poses a major challenge for cancer immunotherapy. The present study was designed to determine whether the WNT1-inducible signaling pathway protein 2 (WISP2, also referred to as CCN5), a key regulator of tumor cell plasticity, interferes with tumor susceptibility to cytotoxic T-lymphocyte (CTL)-mediated lysis. We found that silencing WISP2 signaling in human breast adenocarcinoma MCF7 cells impairs CTL-mediated cell killing by a mechanism involving stem cell marker Kruppel-like factor-4 (KLF-4) induction and microRNA-7 (miR-7) downregulation. Inhibition of transforming growth factor beta (TGF-β) signaling using the A83-01 inhibitor in MCF7-shWISP2 cells resulted in a significant reversal of the epithelial-to-mesenchymal-transitioned (EMT) phenotype, the expression of KLF-4 and a partial recovery of target susceptibility to CTLs. More importantly, we showed that silencing KLF-4 was accompanied by a reduction in MCF7-shWISP2 resistance to CTLs. Using human breast cancer tissues, we demonstrated the coexpression of KLF-4 with EMT markers and TGF-β pathway signaling components. More importantly, we found that KLF-4 expression was accompanied by miR-7 inhibition, which is partly responsible for impairing CTL-mediated lysis. Thus, our data indicate that WISP2 has a role in regulating tumor cell susceptibility through EMT by inducing the TGF-β signaling pathway, KLF-4 expression and miR-7 inhibition. These studies indicate for the first time that WISP2 acts as an activator of CTL-induced killing and suggests that the loss of its function promotes evasion of immunosurveillance and the ensuing progression of the tumor.

Hypoxia-inducible factor-mediated induction of WISP-2 contributes to attenuated progression of breast cancer

Hypoxia and the hypoxia-inducible factor (HIF) signaling pathway trigger the expression of several genes involved in cancer progression and resistance to therapy. Transcriptionally active HIF-1 and HIF-2 regulate overlapping sets of target genes, and only few HIF-2 specific target genes are known so far. Here we investigated oxygen-regulated expression of Wnt-1 induced signaling protein 2 (WISP-2), which has been reported to attenuate the progression of breast cancer. WISP-2 was hypoxically induced in low-invasive luminal-like breast cancer cell lines at both the messenger RNA and protein levels, mainly in a HIF-2α-dependent manner. HIF-2-driven regulation of the WISP2 promoter in breast cancer cells is almost entirely mediated by two phylogenetically and only partially conserved functional hypoxia response elements located in a microsatellite region upstream of the transcriptional start site. High WISP-2 tumor levels were associated with increased HIF-2α, decreased tumor macrophage density, and a better prognosis. Silencing WISP-2 increased anchorage-independent colony formation and recovery from scratches in confluent cell layers of normally low-invasive MCF-7 cancer cells. Interestingly, these changes in cancer cell aggressiveness could be phenocopied by HIF-2α silencing, suggesting that direct HIF-2-mediated transcriptional induction of WISP-2 gene expression might at least partially explain the association of high HIF-2α tumor levels with prolonged overall survival of patients with breast cancer.

Loss of WISP2/CCN5 in estrogen-dependent MCF7 human breast cancer cells promotes a stem-like cell phenotype

It has been proposed that the epithelial-mesenchymal transition (EMT) in mammary epithelial cells and breast cancer cells generates stem cell features. WISP2 (Wnt-1-induced signaling protein-2) plays an important role in maintenance of the differentiated phenotype of estrogen receptor-positive breast cancer cells and loss of WISP2 is associated with EMT. We now report that loss of WISP2 in MCF7 breast cancer cells can also promote the emergence of a cancer stem-like cell phenotype characterized by high expression of CD44, increased aldehyde dehydrogenase activity and mammosphere formation. Higher levels of the stem cell markers Nanog and Oct3/4 were observed in those mammospheres. In addition we show that low-cell inoculums are capable of tumor formation in the mammary fat pad of immunodeficient mice. Gene expression analysis show an enrichment of markers linked to stem cell function such as SOX9 and IGFBP7 which is linked to TGF-β inducible, SMAD3-dependent transcription. Taken together, our data demonstrate that WISP2 loss promotes both EMT and the stem-like cell phenotype.

Wnt1 inducible signalling pathway protein-2 (WISP‑2/CCN5): roles and regulation in human cancers (review)

Wnt1 inducible signalling pathway protein-2 (WISP‑2), also known as CCN5, CT58, CTGF-L, CTGF-3, HICP and Cop1, is one of the 3 WNT1 inducible proteins that belongs to the CCN family. This family of members has been shown to play multiple roles in a number of pathophysiological processes, including cell proliferation, adhesion, wound healing, extracellular matrix regulation, epithelial-mesenchymal transition, angiogenesis, fibrosis, skeletal development and embryo implantation. Recent results suggest that WISP-2 is relevant to tumorigenesis and malignant transformation, particularly in breast cancer, colorectal cancer and hepatocarcinoma. Notably, its roles in cancer appear to vary depending on cell/tumour type and the microenvironment. The striking difference in the structure of WISP-2 in comparison with the other 2 family members may contribute to its difference in functions, which leads to the hypothesis that WISP-2 may act as a dominant-negative regulator of other CCN family members. In the present review, we summarise the roles, regulation and underlying mechanism of WISP-2 in human cancers.

A comparative study of clinicopathological significance, FGFBP1, and WISP-2 expression between squamous cell/adenosquamous carcinomas and adenocarcinoma of the gallbladder

BACKGROUND

The differences in clinical, pathological, and biological characteristics between adenocarcinoma (AC) and squamous cell/adenosquamous carcinoma (SC/ASC) of gallbladder cancer have not been well documented. This study is to compare the clinicopathological characteristics and FGFBP1 and WISP-2 expression between AC and SC/ASC patients.

METHODS

We examined FGFBP1 and WISP-2 expression in 46 SC/ASC and 80 AC samples using immunohistochemistry and analyzed their correlations with clinicopathological characteristics.

RESULTS

SC/ASCs occur more frequently in older patients and often correspond to larger tumor masses than ACs. Positive FGFBP1 and negative WISP-2 expression were significantly associated with lymph node metastasis and invasion of SC/ASCs and ACs. In addition, positive FGFBP1 and negative WISP-2 expression were significantly associated with differentiation and TMN stage in ACs. Univariate Kaplan-Meier analysis showed that either elevated FGFBP1 (p < 0.001) or lowered WISP-2 (p < 0.001) expression was closely associated with decreased overall survival in both SC/ASC and AC patients. Multivariate Cox regression analysis showed that positive FGFBP1 expression (p = 0.001) or negative WISP-2 expression (p = 0.035 for SC/ASC and p = 0.009 for AC) is an independent predictor of poor prognosis in both SC/ASC and AC patients. We also revealed that differentiation, tumor size, TNM stage, lymph node metastasis, invasion, and surgical procedure were associated with survival of both SC/ASC and AC patients.

CONCLUSION

Our study suggested that the overexpression of FGFBP1 or loss of WISP-2 expression is closely related to the metastasis, invasion and poor prognosis of gallbladder cancer.

Glucocorticoids induce CCN5/WISP-2 expression and attenuate invasion in oestrogen receptor-negative human breast cancer cells

CCN5 (cysteine-rich 61/connective tissue growth factor/nephroblastoma overexpressed 5)/WISP-2 [WNT1 (wingless-type MMTV integration site family, member 1)-inducible signalling pathway protein 2] is an oestrogen-regulated member of the CCN family. CCN5 is a transcriptional repressor of genes associated with the EMT (epithelial-mesenchymal transition) and plays an important role in maintenance of the differentiated phenotype in ER (oestrogen receptor)-positive breast cancer cells. In contrast, CCN5 is undetectable in more aggressive ER-negative breast cancer cells. We now report that CCN5 is induced in ER-negative breast cancer cells such as MDA-MB-231 following glucocorticoid exposure, due to interaction of the endogenous glucocorticoid receptor with a functional glucocorticoid-response element in the CCN5 gene promoter. Glucocorticoid treatment of MDA-MB-231 cells is accompanied by morphological alterations, decreased invasiveness and attenuated expression of mesenchymal markers, including vimentin, cadherin 11 and ZEB1 (zinc finger E-box binding homeobox 1). Interestingly, glucocorticoid exposure did not increase CCN5 expression in ER-positive breast cancer cells, but rather down-regulated ER expression, thereby attenuating oestrogen pathway signalling. Taken together, our results indicate that glucocorticoid treatment of ER-negative breast cancer cells induces high levels of CCN5 expression and is accompanied by the appearance of a more differentiated and less invasive epithelial phenotype. These findings propose a novel therapeutic strategy for high-risk breast cancer patients.

The effect of combination treatment with trenbolone acetate and estradiol-17β on skeletal muscle expression and plasma concentrations of oxytocin in sheep

Implantation of trenbolone acetate (TBA) in conjunction with estradiol-17β (E(2)) increases growth, feed conversion efficiency, and carcass leanness in cattle. Our previous study in Brahman steers suggested that the neuropeptide hormone oxytocin (OXT) may be involved in increasing muscle growth after TBA-E(2) treatment. The present study aimed to determine whether OXT mRNA expression in the longissimus muscle (LM) is also up-regulated in TBA-E(2-)implanted wethers as has been found in steers. Real-time quantitative PCR was used to measure the expression of the gene encoding the OXT precursor, three genes with increased expression in the LM muscle of TBA-E(2)-treated steers, MYOD1 (muscle transcription factor), GREB1 (growth regulation by estrogen in breast cancer 1), and WISP2 (Wnt-1 inducible signaling pathway protein 2), and two genes encoding IGF pathway proteins, IGF1, IGFR, in the LM of both untreated and TBA-E(2)-treated wethers. The expression of OXT mRNA in wethers that received the TBA-E(2) treatment was increased ~4.4-fold (P = 0.01). TBA-E(2) treatment also induced a 2.3-fold increase in circulating OXT (P = 0.001). These data, together with the observation that untreated wethers had much higher baseline concentrations of circulating OXT than previously observed in steers, suggest that wethers and steers have quite different OXT hormone systems. TBA-E(2) treatment had no effect on the expression of IGF1, IGFR, and the muscle regulatory gene MYOD1 mRNA levels in wethers (P ≥ 0.15), but there was an increase in the expression of the two growth-related genes, GREB1 (P = 0.001) and WISP2 (P = 0.04). Both genes are common gene targets for both the estrogen and androgen signaling pathways. Consequently, their actions may contribute to the positive interaction between TBA and E(2) on additive improvements on muscle growth.

CCN5/WISP-2: A micromanager of breast cancer progression

The gain of plasticity by a subset of cancer cells is a unique but common sequence of cancer progression from epithelial phenotype to mesenchymal phenotype (EMT) that is followed by migration, invasion and metastasis to a distant organ, and drug resistance. Despite multiple studies, it is still unclear how cancer cells regulate plasticity. Recent studies from our laboratory and others' proposed that CCN5/WISP-2, which is found intracellularly (in the nucleus and cytoplasm) and extracellularly, plays a negative regulator of plasticity. It prevents the EMT process in breast cancer cells as well as pancreatic cancer cells. Multiple genetic insults, including the gain of p53 mutations that accumulate over the time, may perturb CCN5 expression in non-invasive breast cancer cells, which ultimately helps cells to gain invasive phenotypes. Moreover, emerging evidence indicates that several oncogenic lesions such as miR-10b upregulation and activation of TGF-β-signaling can accumulate during CCN5 crisis in breast cancer cells. Collectively, these studies indicate that loss of CCN5 activity may promote breast cancer progression; application of CCN5 protein may represent a novel therapeutic intervention in breast cancer and possibly pancreatic cancer.

Cysteine-rich 61-connective tissue growth factor-nephroblastoma-overexpressed 5 (CCN5)/Wnt-1-induced signaling protein-2 (WISP-2) regulates microRNA-10b via hypoxia-inducible factor-1α-TWIST signaling networks in human breast cancer cells

MicroRNAs (miRNAs) are naturally occurring single-stranded RNA molecules that post-transcriptionally regulate the expression of target mRNA transcripts. Many of these target mRNA transcripts are involved in regulating processes commonly altered during tumorigenesis and metastatic growth. These include cell proliferation, differentiation, apoptosis, migration, and invasion. Among the several miRNAs, miRNA-10b (miR-10b) expression is increased in metastatic breast cancer cells and positively regulates cell migration and invasion through the suppression of the homeobox D10 (HOXD10) tumor suppressor signaling pathway. In breast metastatic cells, miR-10b expression is enhanced by a transcription factor TWIST1. We find that miR-10b expression in breast cancer cells can be suppressed by CCN5, and this CCN5 effect is mediated through the inhibition of TWIST1 expression. Moreover, CCN5-induced inhibition of TWIST1 expression is mediated through the translational inhibition/modification of hypoxia-inducible factor-1α via impeding JNK signaling pathway. Collectively, these studies suggest a novel regulatory pathway exists through which CCN5 exerts its anti-invasive function. On the basis of these findings, it is plausible that reactivation of CCN5 in miR-10b-positive invasive/metastatic breast cancers alone or in combination with current therapeutic regimens could provide a unique, alternative strategy to existing breast cancer therapy.

CCN5, a novel transcriptional repressor of the transforming growth factor β signaling pathway

CCN5 is a member of the CCN (connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed) family and was identified as an estrogen-inducible gene in estrogen receptor-positive cell lines. However, the role of CCN5 in breast carcinogenesis remains unclear. We report here that the CCN5 protein is localized mostly in the cytoplasm and in part in the nucleus of human tumor breast tissue. Using a heterologous transcription assay, we demonstrate that CCN5 can act as a transcriptional repressor presumably through association with histone deacetylase 1 (HDAC1). Microarray gene expression analysis showed that CCN5 represses expression of genes associated with epithelial-mesenchymal transition (EMT) as well as expression of key components of the transforming growth factor β (TGF-β) signaling pathway, prominent among them TGF-βRII receptor. We show that CCN5 is recruited to the TGF-βRII promoter, thereby providing a mechanism by which CCN5 restricts transcription of the TGF-βRII gene. Consistent with this finding, CCN5, we found, functions to suppress TGF-β-induced transcriptional responses and invasion that is concomitant with EMT. Thus, our data uncovered CCN5 as a novel transcriptional repressor that plays an important role in regulating tumor progression functioning, at least in part, by inhibiting the expression of genes involved in the TGF-β signaling cascade that is known to promote EMT.

Cyr61/CCN1 signaling is critical for epithelial-mesenchymal transition and stemness and promotes pancreatic carcinogenesis

BACKGROUND

Despite recent advances in outlining the mechanisms involved in pancreatic carcinogenesis, precise molecular pathways and cellular lineage specification remains incompletely understood.

RESULTS

We show here that Cyr61/CCN1 play a critical role in pancreatic carcinogenesis through the induction of EMT and stemness. Cyr61 mRNA and protein were detected in the early precursor lesions and their expression intensified with disease progression. Cyr61/CCN1 expression was also detected in different pancreatic cancer cell lines. The aggressive cell lines, in which the expressions of mesenchymal/stem cell molecular markers are predominant; exhibit more Cyr61/CCN1 expression. Cyr61 expression is exorbitantly higher in cancer stem/tumor initiating Panc-1-side-population (SP) cells. Upon Cyr61/CCN1 silencing, the aggressive behaviors are reduced by obliterating interlinking pathobiological events such as reversing the EMT, blocking the expression of stem-cell-like traits and inhibiting migration. In contrast, addition of Cyr61 protein in culture medium augments EMT and stemness features in relatively less aggressive BxPC3 pancreatic cancer cells. Using a xenograft model we demonstrated that cyr61/CCN1 silencing in Panc-1-SP cells reverses the stemness features and tumor initiating potency of these cells. Moreover, our results imply a miRNA-based mechanism for the regulation of aggressive behaviors of pancreatic cancer cells by Cyr61/CCN1.

CONCLUSIONS

In conclusion, the discovery of the involvement of Cyr61/CCN1 in pancreatic carcinogenesis may represent an important marker for PDAC and suggests Cyr61/CCN1 can be a potential cancer therapeutic target.

Ron receptor tyrosine kinase activation confers resistance to tamoxifen in breast cancer cell lines

Although tamoxifen treatment is associated with improved survival in patients with estrogen receptor (ER)-positive breast tumors, resistance remains an important clinical obstacle. Signaling through growth factor signaling pathways, in particular through receptor tyrosine kinases, has been demonstrated to confer tamoxifen resistance in an estradiol-independent manner. The Ron receptor tyrosine kinase, a member of the c-Met family of receptors, is expressed in a number of human epithelial tumors, and elevated expression of Ron is associated with poor prognosis in women with breast cancer. In this report, we evaluated the role of Ron receptor activation in conferring resistance to tamoxifen in human and murine breast cancer cell lines. Activation of Ron by its ligand, hepatocyte growth factor-like protein (HGFL) was associated with partial rescue from tamoxifen-induced growth inhibition in Ron-expressing cell lines. Western analysis revealed that treatment of the T47D human breast cancer cell line with tamoxifen and HGFL was associated with increased phosphorylation of mitogen-activated protein kinase (MAPK) 1/2 and phosphorylation of serine residue 118 of ER. Expression of ER-dependent genes was increased in cells treated with tamoxifen and HGFL by quantitative reverse transcription-polymerase chain reaction. All of these effects were inhibited by treatment with either a Ron-neutralizing antibody or a MEK1 inhibitor, suggesting the specificity of the effect to Ron, and the involvement of the MAPK 1/2 signaling pathway. In summary, these results illustrate a novel connection between the Ron receptor tyrosine kinase and an important mechanism of tamoxifen resistance in breast cancer.

CCN5: biology and pathophysiology

CCN5 is one of six proteins in the CCN family. This family of proteins has been shown to play important roles in many processes, including proliferation, migration, adhesion, extracellular matrix regulation, angiogenesis, tumorigenesis, fibrosis, and implantation. In this review, we focus on the biological and putative pathophysiological roles of CCN5. This intriguing protein is structurally unique among the CCN family members, and has a unique biological activity profile as well.

CCN5: biology and pathophysiology

CCN5 is one of six proteins in the CCN family. This family of proteins has been shown to play important roles in many processes, including proliferation, migration, adhesion, extracellular matrix regulation, angiogenesis, tumorigenesis, fibrosis, and implantation. In this review, we focus on the biological and putative pathophysiological roles of CCN5. This intriguing protein is structurally unique among the CCN family members, and has a unique biological activity profile as well.

CCN5/WISP-2 expression in breast adenocarcinoma is associated with less frequent progression of the disease and suppresses the invasive phenotypes of tumor cells

Although previous in vitro studies predicted that CCN5/WISP-2 may act as an anti-invasive gene in breast cancer, the distribution pattern of CCN5 in breast cancer samples is conflicting. Thus, we systematically investigated the CCN5 expression profile in noninvasive and invasive breast tumor samples and its functional relevance in breast cancer progression. The studies showed that CCN5 expression is biphasic, such that in normal samples CCN5 expression is undetectable, whereas its expression is markedly increased in noninvasive breast lesions, including atypical ductal hyperplasia and ductal carcinoma in situ. Further, CCN5 mRNA and protein levels are significantly reduced as the cancer progresses from a noninvasive to invasive type. Additionally, we showed that CCN5 mRNA and protein level was almost undetectable in poorly differentiated cancers compared with the moderately or well-differentiated samples and its expression inversely correlated with lymph node positivity. The result was further supported by evaluating the RNA expression profile in microdissected sections using real-time PCR analysis. Therefore, our data suggest a protective function of CCN5 in noninvasive breast tumor cells. This hypothesis was further supported by our in vitro studies illuminating that CCN5 is a negative regulator of migration and invasion of breast cancer cells, and these events could be regulated by CCN5 through the modulation of the expression of genes essential for an invasive front. These include Snail-E-cadherin signaling and matrix metalloproteinase (MMP)-9 and MMP-2. Collectively, these studies suggest that the protective effect of CCN5 in breast cancer progression may have important therapeutic implications.

VEGF-A165 induces human aortic smooth muscle cell migration by activating neuropilin-1-VEGFR1-PI3K axis

Vascular smooth muscle cells (SMCs), one of the major cell types of the vascular wall, play a critical role in the process of angiogenesis under both physiological and pathophysiological conditions, including the cancer microenvironment. Previous studies have shown that VEGF-A 165 augments vascular SMC migration via VEGFR2 (KDR/Flk1) pathways. In this study, we found that VEGF-A 165 (recombinant protein or breast tumor cell-secreted) is also capable of inducing migration of VEGFR2-negative human aortic smooth muscle cells (hAOSMCs), and this induction is mediated through a molecular cross-talk of neuropilin-1 (NRP-1), VEGFR1 (Flt-1), and phosphoinositide 3-kinase (PI3K)/Akt signaling kinase. We found that VEGF-A 165 induces hAOSMC migration parallel with the induction of NRP-1 and VEGFR1 expressions and their associations along with the activation of PI3K/Akt. Neutralization of VEGF action by its antibody or inhibition of VEGF-induced PI3K/Akt kinase activation by wortmannin, a PI3K/Akt specific inhibitor, results in inhibition of VEGF-induced hAOSMC migration. Moreover, RNAi-mediated elimination of the NRP-1 expression or blocking of the activity of VEGFR1 by its antibody in hAOSMCs impairs the VEGF-A 165-induced migration of these cells as well as activation of PI3K/Akt kinase. Collectively, these results establish, for the first time, a mechanistic link among VEGF-A 165, NRP-1, VEGFR1, and PI3K/Akt in the regulation of migration of human vascular smooth muscle cells that eventually could be involved in the angiogenic switch.

Gene expression profiling to identify markers associated with deregulated hTERT in HPV-transformed keratinocytes and cervical cancer

Although high-risk human papillomavirus (HPV) infection plays a major role in the development of cervical cancer, additive oncogenic events are involved as well. One key event involves increased activity of telomerase resulting from a deregulated expression of its catalytic subunit hTERT. Our previous microcell-mediated chromosome transfer studies revealed that introduction of human chromosome 6 in the HPV16-immortalized keratinocyte cell line FK16A and in the HPV16-containing cervical cancer cell line SiHa induced growth arrest, resulting from a repression of hTERT mRNA expression and telomerase activity. Here, this model was used to analyze expression profiles associated with hTERT deregulation in HPV-transformed cells. Microarray expression analysis of 12 FK16A/chromosome 6 hybrids, 4 of which were negative for endogenous hTERT and 8 of which were positive for endogenous hTERT, resulted in the identification of 164 differentially expressed genes. Differential expression of a selection of 5 genes was verified by real-time RT-PCR. Of these 164 genes, 32 were also differentially expressed in other HPV transformed cells with deregulated hTERT. For 2 of these genes, encoding AQP3 and MGP, altered expression in hTERT positive cervical carcinomas was confirmed by real-time RT-PCR and immunohistochemistry, respectively. Moreover, increased MGP protein expression was significantly more frequent in high-grade cervical premalignant lesions with elevated hTERT mRNA expression compared to those without. In summary, we identified 32 candidate biomarkers for deregulated hTERT mRNA expression, which may enable the identification of cervical premalignant lesions that are at highest risk to progress to invasive cancer.

Role of WISP-2/CCN5 in the maintenance of a differentiated and noninvasive phenotype in human breast cancer cells

WISP-2/CCN5 is an estrogen-regulated member of the "connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed" (CCN) family of the cell growth and differentiation regulators. The WISP-2/CCN5 mRNA transcript is undetectable in normal human mammary cells, as well as in highly aggressive breast cancer cell lines, in contrast with its higher level in the breast cancer cell lines characterized by a more differentiated phenotype. We report here that knockdown of WISP-2/CCN5 by RNA interference in estrogen receptor alpha (ERalpha)-positive MCF-7 breast cancer cells induced an estradiol-independent growth linked to a loss of ERalpha expression and promoted epithelial-to-mesenchymal transdifferentiation. In contrast, forced expression of WISP-2/CCN5 directed MCF-7 cells toward a more differentiated phenotype. When introduced into the poorly differentiated, estrogen-independent, and invasive MDA-MB-231 breast cancer cells, WISP-2/CCN5 was able to reduce their proliferative and invasive phenotypes. In a series of ERalpha-positive tumor biopsies, we found a positive correlation between the expression of WISP-2/CCN5 and ID2, a transcriptional regulator of differentiation in normal and transformed breast cells. We propose that WISP-2/CCN5 is an important regulator involved in the maintenance of a differentiated phenotype in breast tumor epithelial cells and may play a role in tumor cell invasion and metastasis.

Transcriptome profile of Trypanosoma cruzi-infected cells: simultaneous up- and down-regulation of proliferation inhibitors and promoters

As Trypanosoma cruzi, the etiological agent of Chagas disease, multiplies in the cytoplasm of nucleated host cells, infection with this parasite is highly likely to affect host cells. We performed an exhaustive transcriptome analysis of T. cruzi-infected HeLa cells using an oligonucleotide microarray containing probes for greater than 47,000 human gene transcripts. In comparison with uninfected cells, those infected with T. cruzi showed greater than threefold up-regulation of 41 genes and greater than threefold down-regulation of 23 genes. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of selected, differentially expressed genes confirmed the microarray data. Many of these up- and down-regulated genes were related to cellular proliferation, including seven up-regulated genes encoding proliferation inhibitors and three down-regulated genes encoding proliferation promoters, strongly suggesting that T. cruzi infection inhibits host cell proliferation, which may allow more time for T. cruzi to replicate and produce its intracellular nests. These findings provide new insight into the molecular mechanisms by which intracellular T. cruzi infection influences the host cell, leading to pathogenicity.

CCN5 Expression in mammals. II. Adult rodent tissues

CCN5 is a secreted heparin- and estrogen-regulated matricellular protein that inhibits vertebrate smooth muscle cell proliferation and motility. CCN5 is expressed throughout murine embryonic development in most organs and tissues. However, after embryonic development is complete, we hypothesized that CCN5 distribution would be largely restricted to small set of tissues, including smooth muscle cells of the arteries, uterus, airway, and digestive tract. Because CCN5 inhibits proliferation of smooth muscle cells in vitro, it might function to prevent excessive growth in vivo. In contrast, another member of the CCN family, CCN2, promotes smooth muscle cell proliferation in vitro, and thus it was expected that its expression levels would be low in uninjured normal adult tissues. Frozen sections from adult tissues and organs were analyzed immunohistochemically using anti-CCN5 and anti-CCN2 antibodies. Both proteins were detected in arteries, the uterus, bronchioles, and the digestive tract as expected, and also in many other tissues including the pancreas, spleen, liver, skeletal muscle, ovary, testis, thymus, brain, olfactory epithelium, and kidney. CCN5 and CCN2 protein was found in smooth muscle, endothelial cells, epithelial cells, skeletal muscle, cells of the nervous system, and numerous other cell types. In many cells, both CCN5 and CCN2 was present in the nucleus. Rather than having opposite patterns of localization, CCN5 and CCN2 often had similar sites of expression. The wide distribution of both CCN5 and CCN2 suggests that both proteins have additional biological functions beyond those previously identified in specific cellular and pathological models.

CCN5 expression in mammals : I. Embryonic and fetal tissues of mouse and human

The six proteins of the CCN family have important roles in development, angiogenesis, cell motility, proliferation, and other fundamental cell processes. To date, CCN5 distribution in developing rodents and humans has not been mapped comprehensively. CCN5 strongly inhibits adult smooth muscle cell proliferation and motility. Its anti-proliferative action predicts that CCN5 would not be present in developing tissues until the proliferation phase of tissue morphogenesis is complete. However, estrogen induces CCN5 expression in epithelial and smooth muscle cells, suggesting that CCN5 might be widely expressed in embryonic tissues exposed to high levels of estrogen. 9-16 day murine embryos and fetuses and 3-7 month human fetal tissues were analyzed by immunohistochemistry. CCN5 was detected in nearly all developing tissues. CCN5 protein expression was initially present in most tissues, and at later times in development tissue-specific expression differences were observed. CCN5 expression was particularly strong in vascular tissues, cardiac muscle, bronchioles, myotendinous junctions, and intestinal smooth muscle and epithelium. CCN5 expression was initially absent in bone cartilaginous forms but was increasingly expressed during bone endochondral ossification. Widespread CCN5 mRNA expression was detected in GD14.5 mice. Although CCN2 and CCN5 protein expression patterns in some adult pathologic conditions are inversely expressed, this expression pattern was not found in developing mouse and human tissues. The widespread expression pattern of CCN5 in most embryonic and fetal tissues suggests a diverse range of functions for CCN5.

Loss of WISP-2/CCN5 signaling in human pancreatic cancer: A potential mechanism for epithelial-mesenchymal-transition

The objective of this study was to explore the pathophysiological relevance of WISP-2/CCN5 in progression of human pancreatic adenocarcinoma (PAC). We found WISP-2/CCN5 mRNA and protein expression was faint and sporadic in PAC and detected in only 8.7-20% of the samples with varying grades as compared to adjacent normal and chronic pancreatitis samples where expression was very high in the ducts and acini. Colocalization studies in tissue-microarray slides revealed WISP-2/CCN5 mRNA loss was associated with p53 overexpression in PAC. Like tissue samples, p53 mutant-PAC cell lines show loss of WISP-2/CCN5. Moreover, functional analysis studies demonstrate exposure of pancreatic cancer cells to WISP-2/CCN5 recombinant protein enhances mesenchymal-epithelial-transition (MET). Collectively, we suggest WISP-2/CCN5 silencing may be a critical event during differentiation and progression of PAC and mutant p53 is possibly an important player in pursuing this episode.

Deletion of Tip30 leads to rapid immortalization of murine mammary epithelial cells and ductal hyperplasia in the mammary gland

Transformation of mammary epithelial cells (MECs) from the normal to the neoplastic stage requires the dysregulation of tumor suppressor genes and proto-oncogenes. Tip30 is a tumor suppressor that can inhibit estrogen receptor-mediated transcription in MECs, but its role in MEC proliferation remains unknown. Here, we show that deleting the Tip30 gene leads to ductal hyperplasia in mouse mammary glands early in life and extensive mammary hyperplasia with age. Tip30(-/-) mammary glands transplanted into wild-type mammary fat pads also display mammary trees with extensive ductal hyperplasia. Strikingly, Tip30 deletion promotes proliferation of primary MECs and results in rapid immortalization of MECs in vitro relative to wild-type cells. Gene array analysis identified significant increases in the expression of mammary epithelial growth factors Wisp2 and Igf-1 in Tip30(-/-) cells. Knockdown of either Wisp2 or Igf-1 using short interfering RNA dramatically inhibited proliferation of Tip30(-/-) cells. Together, these results suggest that Tip30 is an intrinsic and negative regulator of MEC proliferation partly through the inhibition of Wisp2 and Igf-1 expression, and its absence in the mammary gland may predispose MECs to neoplastic transformation.

Differential Expression and Prognostic Implications of the CCN Family Members WISP-1, WISP-2, and WISP-3 in Human Breast Cancer

BACKGROUND

The CCN family has three Wnt-inducted secreted proteins named WISP-1, WISP-2 and WISP-3. These molecules are known to play a diverse role in cells, but their role in cancer cells remains controversial.

METHODS

In this study, we analyzed the expression of the three WISP molecules at the mRNA and protein levels in a cohort of 122 human breast tumors and 32 normal breast tissues, and we correlated these findings with patients' clinical outcomes.

RESULTS

WISP-1 transcripts were found in lower levels in node-positive tumors compared with node-negative tumors (P < .05); were lower in patients with a moderate (P = .01) and poor Nottingham Prognostic Index prognosis (P < .05) compared with good prognostic groups; were of significantly lower level in grade 3 differentiated tumors (P < .05) compared with grade 1; and were of lower levels in patients who developed metastasis and died from breast cancer-related causes (P < .05 in both comparisons). Almost the reverse was found to be true for WISP-2, which had greater levels of expression in node-positive tumors (P = .0043); higher levels in both moderate and poor prognostic groups compared with the good prognostic group (both P < .05); greater level in both grade 2 and 3 when compared with grade 1 (both P < .05); and higher levels in patients who went on to develop metastases (P < .01). WISP-3 transcript levels showed no statistically significant differences between groups.

CONCLUSIONS

WISPs may play important but contrasting roles in breast cancer. WISP-1 seems to act as a tumor suppressor and WISP-2 as a factor that stimulates aggressiveness; WISP-3 has no definable beneficial or detrimental role.

Insulin-like Growth Factor-1 (IGF-1) Induces WISP-2/CCN5 via Multiple Molecular Cross-talks and Is Essential for Mitogenic Switch by IGF-1 Axis in Estrogen Receptor–Positive Breast Tumor Cells

Previously, we have shown that the expression of Wnt-1-induced signaling protein-2 (WISP-2), also known as CCN5, can be regulated by multiple stimulants in estrogen receptor (ER)-positive breast tumor cells to exert their mitogenic action in these cells. Here, we show that insulin-like growth factor-1 (IGF-1), a strong mitogen, enhanced the expression of the WISP-2/CCN5 gene parallel with the induction of proliferation of ER-positive breast tumor cells. An additive effect was also seen in combination with estrogen. Perturbation of IGF-1-induced WISP-2/CCN5 expression by WISP-2-specific RNA interference impaired the mitogenic action of IGF-1 on ER-positive breast tumor cells. Furthermore, the studies have shown that the multiple molecular cross-talks and side-talks among IGF-1R, ER-alpha, and phosphatidylinositol 3-kinase (PI3K)/Akt signaling molecules are required to induce WISP-2/CCN5 mRNA by IGF-1 in ER-positive, noninvasive breast tumor cells. Because a pure anti-ER ICI 182,780 is not only able to suppress the up-regulation of WISP-2/CCN5 mRNA expression by IGF-1, it also suppresses the PI3K/Akt activity induced by IGF-1 in MCF-7 cells; we anticipate that the membrane ER receptor may participate in this event. Collectively, these studies propose for the first time that WISP-2/CCN5 is an integral signaling molecule in mitogenic action of IGF-1 axis in ER-positive human breast tumor cells.

Breast cancer cells secreted platelet-derived growth factor-induced motility of vascular smooth muscle cells is mediated through neuropilin-1

Motility of vascular smooth muscle cells (SMCs) is an essential step for both normal and pathologic angiogenesis. We report here that breast tumor cells, such as MCF-7 and MDA-MB-231, can modulate this SMC migration. We present evidence that the tumor cell-derived platelet-derived growth factor (PDGF) is the key regulator of vascular SMCs motility induced by breast cancer cells. PDGF significantly upregulates neuropilin-1 (NRP-1) mRNA expression and protein production in aortic smooth muscle cells (AOSMCs) and depletion of NRP-1 production by AOSMCs with specific short hairpin RNA (shRNA) prevents the PDGF-dependent migration of vascular SMCs. Moreover, we demonstrate that PDGF physically interacts with NRP-1. We propose that tumor-derived PDGF and NRP-1 of AOSMCs function as a relay system that promotes motility of vascular SMCs.