WISP3 (CCN6) is a secreted tumor-suppressor protein that modulates IGF signaling in inflammatory breast cancer

Fibronectin promotes tumor angiogenesis and progression of non-small-cell lung cancer by elevating WISP3 expression via FAK/MAPK/ HIF-1α axis and activating wnt signaling pathway

BACKGROUND

Fibronectin, an extracellular matrix protein, has been reported to be associated with heterogeneous cancer stemness, angiogenesis and progression in multiple cancer types. However, the roles and the underlying mechanism of fibronectin on the progression NSCLC need to be further elucidated.

METHODS

Public dataset such as Kaplan-Meier Plotter was used to determine the prognostic significance of genes. The correlation of different protein expression in clinical and xenograft tissues was tested by immunohistochemistry experiment. Both in vitro and in vivo experiments were performed to determine the role of fibronectin on the tumor growth, metastasis, and angiogenesis in NSCLC. The activation of key signaling pathway under fibronectin was examined by WB assay. RNA-seq was applicated to screening the target gene of fibronectin. Rescue experiment was performed to confirm the role of target gene in fibronectin-mediated function in NSCLC. Finally, luciferase and CHIP assays were used to elucidate the mechanism by which fibronectin regulated the target gene.

RESULTS

Our results revealed that fibronectin was up-regulated in cancer tissues compared with the normal ones in NSCLC patients. Dish- coated fibronectin enhanced the tumor growth, metastasis, and angiogenesis of NSCLC in vitro and in vivo by promoting EMT and maintaining stemness of NSCLC cells. As expected, fibronectin activated FAK and its downstream MAPK/ERK signaling pathway. WISP3 was screened as a potential target gene of fibronectin. Interestingly, WISP3 effectively activated Wnt signaling pathway, and knockdown of WISP3 effectively blocked the influence of fibronectin on the migration, invasion and vascular structure formation potential of NSCLC cells. Our data also manifested that fibronectin elevated the transcription of WISP3 gene by promoting the binding of HIF-1α to the promoter region of WISP3 in NSCLC cells.

CONCLUSIONS

Our findings sketched the outline of the route for fibronectin exert its role in NSCLC, in which fibronectin activated downstream FAK and MAPK/ERK signaling pathways, and mediated the accumulation of HIF-1α. Then, HIF-1α enabled the transcription of WISP3, and subsequently promoted the activation of Wnt signaling pathway, and finally enhanced the tumor growth, metastasis, and angiogenesis in NSCLC.

WISP3 suppresses ESCC progression by inhibiting the IGF-2-IGF1R-AKT signaling cascade

Esophageal squamous cell carcinoma (ESCC) is a major health problem worldwide, especially in the Chinese population. However, the intrinsic molecular mechanisms of ESCC progression are largely unclear, thus there is an unmet need to identify essential genes governing this disease. Here, we discovered WISP3, an important member of the CCN family, is markedly downregulated in ESCC tissues compared to the normal esophageal epithelium. Downregulation of WISP3 in cancer tissue correlates with worse overall survival of ESCC patients. Using ESCC cell lines as models, we found that forced expression of WISP3 not only suppressed proliferation and migration of cancer cells in vitro, but also inhibited ESCC tumor growth and metastasis in vivo. On the contrary, WISP3 depletion strongly promoted the tumorigenicity of ESCC cells. Mechanistically, we found that WISP3 negates the activity of AKT via inhibiting the IGF-2-IGF1R signaling cascade, which mediates the tumor-suppressive function of WISP3 in esophageal cancers. Together, we identified a novel factor driving the development of ESCC, and revealed a potential therapeutic target for ESCC treatment.

The matricellular protein CCN6 differentially regulates mitochondrial metabolism in normal epithelium and in metaplastic breast carcinomas

Metaplastic breast carcinoma (MBC) is an aggressive subtype of triple negative breast cancer with undefined precursors, limited response to chemotherapy, and frequent distant metastasis. Our laboratory has reported that CCN6/WISP3, a secreted protein that regulates growth factor signaling, is downregulated in over 85% of MBCs. Through generation of a mammary epithelial cell-specific Ccn6 knockout mouse model (MMTV-cre;Ccn6^fl/fl) we have demonstrated that CCN6 is a tumor suppressor for MBC; MMTV-cre;Ccn6^fl/fl mice develop tumors recapitulating the histopathology and proteogenomic landscape of human MBC, but the mechanisms need further investigation. In this study, we report that preneoplastic mammary glands of 8-week-old MMTV-Cre;Ccn6^fl/fl female mice show significant downregulation of mitochondrial respiratory chain genes compared to controls, which are further downregulated in MBCs of MMTV-Cre;Ccn6^fl/fl mice and humans. We found that CCN6 downregulation in non-tumorigenic breast cells reduces mitochondrial respiration and increases resistance to stress-induced apoptosis compared to controls. Intracellular ectopic CCN6 protein localizes to the mitochondria in MDA-MB-231 mesenchymal-like breast cancer cells, increases mitochondrial respiration and generation of reactive oxygen species, and reverses doxorubicin resistance of MBC cells. Our data highlight a novel function of CCN6 in the regulation of redox states in preneoplastic progression and suggest potential preventative and treatment strategies against MBC based on CCN6 upregulation.

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.

Comparison of Snail1, ZEB1, E-Cadherin Expression Levels in HPV-Induced Cervical Cancer

Background:

Molecular profiling techniques are the rapid detection of biomarkers in the human papillomavirus (HPV) infected cells. We aimed to measure the expression level of three cell factors including Snail1, ZEB-1, and E-cadherin in cervical cancer (CC), precancerous and healthy samples, simultaneously, to find potential biomarkers.

Methods:

The expression level of the mentioned cell factors were investigated in 72 CC patients, precancerous patients, and healthy controls by using Real-Time PCR.

Results:

The results demonstrated a significant reduction in the expression level of E-cadherin in cancer and precancerous cases than that in healthy cases; whereas the expression level of ZEB-1 and Snail1 were upregulated in cancer and precancerous samples. The receiver operating characteristic (ROC) analyses shows the highest AUC value emerged for Snail1: 1(95% CI: 1-1) in comparing CC and healthy groups with a sensitivity of 100.0 % and specificity of 100.0%.

Conclusion:

The molecular biomarker Snail1 may be helpful to early diagnosis and prognosis of CC in the HPV-infected human populations. Considering the increased expression level of Snail1 in cancer and precancerous tissue compared to healthy tissue as well as the area under the ROC curve, Snail1 can be used for early detection of CC.

A potential prognostic model based on miRNA expression profile in The Cancer Genome Atlas for bladder cancer patients

Background

This study aimed to construct prognostic model by screening prognostic miRNA signature of bladder cancer.

Methods

The miRNA expression profile data of bladder cancer (BC) in The Cancer Genome Atlas (TCGA) were obtained and randomly divided into the training set and the validation set. Differentially expressed miRNAs (DEMs) between BC and normal control samples in the training set were firstly identified, and DEMs related to prognosis were screened by Cox Regression analysis. Then, the MiR Score system was constructed using X-Tile based cutoff points and verified in the validation set. The prognostic clinical factors are selected out by univariate and multivariate Cox Regression analysis. Finally, the mRNAs related to prognosis were screened and the biological pathway analysis was carried out.

Results

We identified the 7-miRNA signature was significantly associated with the patient’s Overall Survival (OS). A prognostic model was constructed based on the prognostic 7-miRNA signature, and possessed a relative satisfying predicted ability both in the training set and validation set. In addition, univariate and multivariate Cox Regression analysis showed that age, lymphovascular invasion and MiR Score were considered as independent prognostic factors in BC patients. Furthermore, based on MiR Score prognostic model, several differentially expressed genes (DEGs), such as WISP3 and UNC5C, as well as their related biological pathway(s), including cell–cell adhesion and neuroactive ligand-receptor interaction, were considered to be related to BC prognosis.

Conclusion

The prognostic model which was constructed based on the prognostic 7-miRNA signature presented a high predictive ability for BC.

Metaplastic Breast Carcinoma: Update on Histopathology and Molecular Alterations

CONTEXT—

Metaplastic carcinoma is a rare, triple-negative carcinoma of the breast that exhibits transformation of part or all of its glandular carcinomatous component into a nonglandular, or metaplastic, component. The World Health Organization currently recognizes 5 variants of metaplastic carcinoma based on their histologic appearance.

OBJECTIVE—

To review the histologic classifications, differential diagnosis, prognosis, and recent laboratory studies of metaplastic breast carcinoma.

DATA SOURCES.—

We reviewed recently published studies that collectively examine metaplastic carcinomas, including results from our own research.

CONCLUSIONS.—

Metaplastic breast carcinoma has a broad spectrum of histologic patterns, often leading to a broad differential diagnosis. Diagnosis can typically be rendered by a combination of morphology and immunohistochemical staining for high-molecular-weight cytokeratins and p63. Recent studies elucidate new genes and pathways involved in the pathogenesis of metaplastic carcinoma, including the downregulation of CCN6 and WNT pathway gene mutations, and provide a novel MMTV-Cre;Ccn6^fl/fl knockout disease-relevant mouse model to test new therapies.

Tumour suppression by targeted intravenous non-viral CRISPRa using dendritic polymers

This article demonstrates a fully synthetic strategy enabling CRISPR-mediated activation of tumour suppressor genes in vivo to reduce tumour burden.

Aberrant gene expression is a hallmark of cancer. Although transcription is traditionally considered ‘undruggable’, the development of CRISPR-associated protein 9 (Cas9) systems offers enormous potential to rectify cancer-associated transcriptional abnormalities in malignant cells. However delivery of this technology presents a critical challenge to overcome in order to realize clinical translation for cancer therapy. In this article we demonstrate for the first time, a fully synthetic strategy to enable CRISPR-mediated activation (CRISPRa) of tumour suppressor genes in vivo using a targeted intravenous approach. We show this via highly efficient transcriptional activation of two model tumour suppressor genes, Mammary Serine Protease Inhibitor (MASPIN, SERPINB5) and cysteine-rich 61/connective tissue growth factor/nephroblastoma-overexpressed 6 (CCN6, WISP3), in a mouse model of breast cancer. In particular, we demonstrate that targeted intravenous delivery of can be achieved using a novel nanoscale dendritic macromolecular delivery agent, with negligible toxicity and long lasting therapeutic effects, outlining a targeted effective formulation with potential to treat aggressive malignancies.

Liver cancer: WISP3 suppresses hepatocellular carcinoma progression by negative regulation of β-catenin/TCF/LEF signalling

Objectives

Wnt1‐inducible signalling pathway protein 3 (WISP3/CCN6) belongs to the CCN (CYR61/CTGF/NOV) family of proteins, dysregulation of this family contributed to the tumorigenicity of various tumours. In this study, we need to explore its role in hepatocellular carcinoma that remains largely elusive.

Materials and Methods

The expression of WISP3/CCN6 was analysed by qRT‐PCR and Western blotting. Effects of WISP3 on proliferation and metastasis of HCC cells were examined, respectively, by MTT assay and Boyden Chamber. Roles of WISP3 on HCC tumour growth and metastatic ability in vivo were detected in nude mice. Related mechanism study was confirmed by immunofluorescence and Western blotting.

Results

The expression of WISP3 was significantly downregulated in HCC clinical samples and cell lines, and reversely correlated with the tumour size. Forced expression of WISP3 in HCC cells significantly suppressed cell growth and migration in vitro as well as tumour growth and metastatic seeding in vivo. In contrast, downregulation of WISP3 accelerated cell proliferation and migration, and promoted in vivo metastasis. Further study revealed that WISP3 inhibited the translocation of β‐catenin to the nucleus by activating glycogen synthase kinase‐3β (GSK3β). Moreover, constitutively active β‐catenin blocked the suppressive effects of WISP3 on HCC.

Conclusions

Our study showed that WISP3 suppressed the progression of HCC by negative regulation of β‐catenin/TCF/LEF signalling, providing WISP3 as a potential therapeutic candidate for HCC.

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.

CCN6 regulates IGF2BP2 and HMGA2 signaling in metaplastic carcinomas of the breast

PURPOSE

Metaplastic breast carcinomas are an aggressive subtype of triple-negative breast cancer (TNBC) in which part or all of the adenocarcinoma transforms into a non-glandular component (e.g., spindled, squamous, or heterologous). We discovered that mammary-specific Ccn6/Wisp3 knockout mice develop mammary carcinomas with spindle and squamous differentiation that share upregulation of the oncofetal proteins IGF2BP2 (IMP2) and HMGA2 with human metaplastic carcinomas. Here, we investigated the functional relationship between CCN6, IGF2BP2, and HMGA2 proteins in vitro and in vivo, and their expression in human tissue samples.

METHODS

MMTV-cre;Ccn6^fl/fl tumors and spindle TNBC cell lines were treated with recombinant CCN6 protein or vehicle. IGF2BP2 was downregulated using shRNAs in HME cells with stable CCN6 shRNA knockdown, and subjected to invasion and adhesion assays. Thirty-one human metaplastic carcinomas were arrayed in a tissue microarray (TMA) and immunostained for CCN6, IGF2BP2, and HMGA2.

RESULTS

CCN6 regulates IGF2BP2 and HMGA2 protein expression in MMTV-cre;Ccn6^fl/fl tumors, in MDA-MB-231 and - 468, and in HME cells. CCN6 recombinant protein reduced IGF2BP2 and HMGA2 protein expression, and decreased growth of MMTV-cre;Ccn6^fl/fl tumors in vivo. IGF2BP2 shRNA knockdown was sufficient to reverse the invasive abilities conferred by CCN6 knockdown in HME cells. Analyses of the TCGA Breast Cancer Cohort (n = 1238) showed that IGF2BP2 and HMGA2 are significantly upregulated in metaplastic carcinoma compared to other breast cancer subtypes. In clinical samples, low CCN6 is frequent in tumors with high IGF2BP2/HMGA2 with spindle and squamous differentiation.

CONCLUSIONS

These data shed light into the pathogenesis of metaplastic carcinoma and demonstrate a novel CCN6/IGF2BP2/HMGA2 oncogenic pathway with biomarker and therapeutic implications.

p38-mediated phosphorylation at T367 induces EZH2 cytoplasmic localization to promote breast cancer metastasis

Overexpression of EZH2 in estrogen receptor negative (ER-) breast cancer promotes metastasis. EZH2 has been mainly studied as the catalytic component of the Polycomb Repressive Complex 2 (PRC2) that mediates gene repression by trimethylating histone H3 at lysine 27 (H3K27me3). However, how EZH2 drives metastasis despite the low H3K27me3 levels observed in ER- breast cancer is unknown. Here we show that in human invasive carcinomas and distant metastases, cytoplasmic EZH2 phosphorylated at T367 is significantly associated with ER- disease and low H3K27me3 levels. p38-mediated EZH2 phosphorylation at T367 promotes EZH2 cytoplasmic localization and potentiates EZH2 binding to vinculin and other cytoskeletal regulators of cell migration and invasion. Ectopic expression of a phospho-deficient T367A-EZH2 mutant is sufficient to inhibit EZH2 cytoplasmic expression, disrupt binding to cytoskeletal regulators, and reduce EZH2-mediated adhesion, migration, invasion, and development of spontaneous metastasis. These results point to a PRC2-independent non-canonical mechanism of EZH2 pro-metastatic function.

WISP-3/CCN6 inhibits apoptosis by regulating caspase pathway after hyperoxia in lung epithelial cells

Cell death is a normal phenomenon in the course of biological development, moreover, which is also a prominent feature in lung exposed to hyperoxia. Severe hypoxia occurs in ALI/ARDS patients, who generally require high concentration oxygen therapy assisted by mechanical ventilation. Nevertheless, high oxygen can cause excessive reactive oxygen species (ROS), leading to apoptosis in lung epithelial cells, which has been reported in our previous study. Herein, the correlation between increments of ROS and CCN6 expression was negative in CCN6-mediated the mitochondria dependent, intrinsic apoptotic pathway. Our latest research explained that CCN6 can inhibit caspase-8 mediated extrinsic apoptotic pathway to protect cells from hyperoxia-induced apoptosis. As demonstrated by Western Blot Analysis, Caspase 8 cleavage and Caspase 3 cleavage in CCN6-depleted cells exceeded the control group treated with high oxygen (48 h). And deletion of CCN6 enhanced caspase-8 activation after hyperoxia shown by Flow Cytometry. Although, it is unclear how CCN6 participated in the regulation of apoptotic pathways, the future targeted therapy drugs inhibiting CCN6 may be useful in the treatment of ALI/ARDS.

Outcomes of patients with inflammatory breast cancer by hormone receptor- and HER2-defined molecular subtypes: A population-based study from the SEER program

Background

The aim of this study was to evaluate the outcomes of patients with inflammatory breast cancer (IBC), with emphasis on the role of molecular subtypes and radiotherapy.

Methods

A retrospective cohort study to investigate overall survival (OS) and breast cancer-specific mortality (BCSM) in patients with IBC was conducted using data obtained by the Surveillance, Epidemiology, and End Results (SEER) program from 2010–2013. Cox multivariate regression was used to calculate the adjusted Hazard Ratios (aHR).

Results

403 patients were eligible for this study. Patients in the group with hormone receptors (HR)+/HER2- subtype had an OS of 79.6% compared with 89.0 % in the group with (HR)+/HER2+ subtype and 76.8% in the HR-/HER2+ group and 62.9% in the triple-negative (TN) group. BCSM was 16.3% for the HR+/HER2- group, 9.8% for the HR+/HER2+ group, 21.7% for the HR-/HER2+ group, and 30.5% for the TN group. For distant metastases, the results showed that there was a high probability of bone metastasis in HR-positive groups, brain and liver metastasis in HER2-positive groups, and lung metastasis in the TN group. Multivariate analysis demonstrated that estrogen receptor and HER2 positivity were associated with better survival and that the TN subtype had a poorer OS and BCSM compared with other subtypes (P<0.05). Furthermore, patients who received radiotherapy were more likely to have improved survival (P< 0.05).

Conclusion

Inflammatory breast cancer appears to alter the prognosis in association with the receptor status and molecular subtypes. Radiotherapy was still considered to be a crucial treatment for patients with IBC.

Association analysis on polymorphisms in WISP3 gene and developmental dysplasia of the hip in Han Chinese population: A case-control study

Developmental dysplasia of the hip (DDH) is a common skeletal disorder whereby genetic factors play a role in etiology. Multiple genes have been reported to be associated with the occurrence of DDH. WISP3 gene was found to be a causative gene for progressive pseudorheumatoid dysplasia (PPD). Reports of WISP3 gene in association with DDH are lacking. We conducted a case-control candidate gene association study enrolling three hundred and eighty-six patients with radiology confirmed DDH and 558 healthy controls. Additional haplotype-analysis was conducted to find the significant haplotype for DDH. Five SNPs rs69306665 (upstream of WISP3), rs1022313 (WISP3), rs1230345 (WISP3), rs17073268 (WISP3) and rs10456877 (downstream of WISP3) were identified for association with DDH, showing significant difference of allele frequencies with similar odds ratio ranging from 0.71 to 0.77 (p < 0.01) between cases and controls. Two haplotypes were identified between cases and controls through haplotype analysis: AAAAA with an odds ratio of 0.76 (95% CI: 0.60-0.98, p = 0.032299) and GGCGG with an odds ratio of 1.67 (95% CI: 1.37-2.04, p = 3.67 ∗ 10^-7). The results suggested WISP3 gene was associated with DDH in Chinese Han population. GGCGG haplotype might be a biomarker for DDH.

Matricellular CCN6 (WISP3) protein: a tumor suppressor for mammary metaplastic carcinomas

Located at 6q22-23, Ccn6 (WISP3) encodes for a matrix-associated protein of the CCN family, characterized by regulatory, rather than structural, roles in development and cancer. CCN6, the least studied member of the CCN family, shares the conserved multimodular structure of CCN proteins, as well as their tissue and cell-type specific functions. In the breast, CCN6 is a critical regulator of epithelial-to-mesenchymal transitions (EMT) and tumor initiating cells. Studies using human breast cancer tissue samples demonstrated that CCN6 messenger RNA and protein are expressed in normal breast epithelia but reduced or lost in aggressive breast cancer phenotypes, especially inflammatory breast cancer and metaplastic carcinomas. Metaplastic carcinomas are mesenchymal-like triple negative breast carcinomas, enriched for markers of EMT and stemness. RNAseq analyses of the TCGA Breast Cancer cohort show reduced CCN6 expression in approximately 50% of metaplastic carcinomas compared to normal breast. Our group identified frameshift mutations of Ccn6 in a subset of human metaplastic breast carcinoma. Importantly, conditional, mammary epithelial-cell specific ccn6 (wisp3) knockout mice develop invasive high-grade mammary carcinomas that recapitulate human spindle cell metaplastic carcinomas, demonstrating a tumor suppressor function for ccn6. Our studies on CCN6 functions in metaplastic carcinoma highlight the potential of CCN6 as a novel therapeutic approach for this specific type of breast cancer.

The matricellular protein CCN6 (WISP3) decreases Notch1 and suppresses breast cancer initiating cells

Increasing evidence supports that the epithelial to mesenchymal transition (EMT) in breast cancer cells generates tumor initiating cells (TICs) but the contribution of the tumor microenvironment to these programs needs further elucidation. CCN6 (WISP3) is a secreted matrix-associated protein (36.9 kDa) of the CCN family (named after CTGF, Cyr61 and Nov) that is reduced or lost in invasive carcinomas of the breast with lymph node metastasis and in inflammatory breast cancer. CCN6 exerts breast cancer growth and invasion inhibitory functions, but the mechanisms remain to be defined. In the present study we discovered that ectopic CCN6 overexpression in triple negative (TN) breast cancer cells and in cells derived from patients is sufficient to induce a mesenchymal to epithelial transition (MET) and to reduce TICs. In vivo, CCN6 overexpression in the TIC population of MDA-MB-231 cells delayed tumor initiation, reduced tumor volume, and inhibited the development of metastasis. Our studies reveal a novel CCN6/Slug signaling axis that regulates Notch1 signaling activation, epithelial cell phenotype and breast TICs, which requires the conserved thrombospondin type 1 (TSP1) motif of CCN6. The relevance of these data to human breast cancer is highlighted by the finding that CCN6 protein levels are inversely correlated with Notch1 intracellular activated form (NICD1) in 69.5% of invasive breast carcinomas. These results demonstrate that CCN6 regulates epithelial and mesenchymal states transition and TIC programs, and pinpoint one responsible mechanism.

Mesenchymal Stem Cell-Induced DDR2 Mediates Stromal-Breast Cancer Interactions and Metastasis Growth

Increased collagen deposition by breast cancer (BC)-associated mesenchymal stem/multipotent stromal cells (MSC) promotes metastasis, but the mechanisms are unknown. Here, we report that the collagen receptor discoidin domain receptor 2 (DDR2) is essential for stromal-BC communication. In human BC metastasis, DDR2 is concordantly upregulated in metastatic cancer and multipotent mesenchymal stromal cells. In MSCs isolated from human BC metastasis, DDR2 maintains a fibroblastic phenotype with collagen deposition and induces pathological activation of DDR2 signaling in BC cells. Loss of DDR2 in MSCs impairs their ability to promote DDR2 phosphorylation in BC cells, as well as BC cell alignment, migration, and metastasis. Female ddr2-deficient mice homozygous for the slie mutation show inefficient spontaneous BC metastasis. These results point to a role for mesenchymal stem cell DDR2 in metastasis and suggest a therapeutic approach for metastatic BC.

WNT1-inducible signaling pathway protein-1 contributes to tumor progression and treatment failure in oral squamous cell carcinoma

WNT1-inducible-signaling pathway protein-1 (WISP-1) belongs to the family of cysteine rich 61/connective tissue growth factor/nephroblastoma overexpressed matricellular proteins, which are involved in various biological processes, including cell adhesion, proliferation, differentiation, angiogenesis and carcinogenesis. In the present study, the expression of WISP-1 was investigated, and its association with clinicopathological factors and prognosis in patients with oral squamous cell carcinoma (OSCC) was evaluated. Additionally, the role of WISP-1 in invasion and apoptosis of human OSCC cells was evaluated. Immunoreactivity of WISP-1 was increased in OSCC tissue compared with adjacent normal tissue samples. High expression of WISP-1 protein was observed in 24/84 (28.57%) OSCC specimens. Additionally, high WISP-1 expression was significantly associated with treatment failure (P=0.042). The 5-year overall survival rate was 33% in patients with high WISP1 expression, and 66% in patients with low WISP-1 expression. WISP-1 expression in the human OSCC SCC-1483 cell line was observed. Furthermore, WISP-1 knockdown using small interfering (si)RNA significantly reduced cell invasion and induced apoptosis compared with control siRNA-transfected cells. These findings suggested that WISP-1 is associated with tumor progression and poor prognosis by increasing tumor cell invasion and inhibiting cell apoptosis in human OSCC.

WISP-1 promotes VEGF-C-dependent lymphangiogenesis by inhibiting miR-300 in human oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC), which accounts for nearly 90% of head and neck cancers, is characterized by a poor prognosis and a low survival rate. Vascular endothelial growth factor-C (VEGF-C) has been implicated in lymphangiogenesis and is correlated with cancer metastasis. WNT1-inducible signaling pathway protein-1 (WISP)-1/CCN4 is an extracellular matrix-related protein that belongs to the CCN family and stimulates many biological functions. Our previous studies showed that WISP-1 plays an important role in OSCC migration and angiogenesis. However, the effect of WISP-1 on VEGF-C regulation and lymphangiogenesis in OSCC is poorly understood. Here, we showed a correlation between WISP-1 and VEGF-C in tissue specimens from patients with OSCC. To examine the lymphangiogenic effect of WISP-1, we used human lymphatic endothelial cells (LECs) to mimic lymphatic vessel formation. The results showed that conditioned media from WISP-1-treated OSCC cells promoted tube formation and cell migration in LECs. We also found that WISP-1-induced VEGF-C is mediated via the integrin αvβ3/integrin-linked kinase (ILK)/Akt signaling pathway. In addition, the expression of microRNA-300 (miR-300) was inhibited by WISP-1 via the integrin αvβ3/ILK/Akt cascade. Collectively, these results reveal the detailed mechanism by which WISP-1 promotes lymphangiogenesis via upregulation of VEGF-C expression in OSCC. Therefore, WISP-1 could serve as therapeutic target to prevent metastasis and lymphangiogenesis in OSCC.

MMTV-cre;Ccn6 knockout mice develop tumors recapitulating human metaplastic breast carcinomas

Metaplastic breast carcinoma is an aggressive form of invasive breast cancer with histological evidence of epithelial to mesenchymal transition (EMT). However, the defining molecular events are unknown. Here we show that CCN6 (WISP3), a secreted matricellular protein of the CCN (CYR61/CTGF/NOV) family, is significantly down regulated in clinical samples of human spindle cell metaplastic breast carcinoma. We generated a mouse model of mammary epithelial-specific Ccn6 deletion by developing a floxed Ccn6 mouse which was bred with an MMTV-Cre mouse. Ccn6^fl/fl; MMTV-Cre mice displayed severe defects in ductal branching and abnormal age-related involution compared to littermate controls. Ccn6^fl/fl ;MMTV-Cre mice developed invasive high grade mammary carcinomas with bona fide EMT, histologically similar to human metaplastic breast carcinomas. Global gene expression profiling of Ccn6^fl/fl mammary carcinomas and comparison of orthologous genes with a human metaplastic carcinoma signature revealed a significant overlap of 87 genes (p=5×10⁻¹¹). Among the shared deregulated genes between mouse and human are important regulators of epithelial morphogenesis including Cdh1, Ck19, Cldn3 and 4, Ddr1, and Wnt10a. These results document a causal role for Ccn6 deletion in the pathogenesis of metaplastic carcinomas with histological and molecular similarities with human disease. We provide a platform to study new targets in the diagnosis and treatment of human metaplastic carcinomas, and a new disease relevant model in which to test new treatment strategies.

Dual roles of CCN proteins in breast cancer progression

The tumor microenvironment has a powerful effect on the development and progression of human breast cancer, which may be used therapeutically. Despite efforts to understand the complex role of the tumor microenvironment in breast cancer development, the specific players and their contributions to tumorigenesis need further investigation. The CCN family of matricellular proteins comprises six members (CCN1-6; CYR61, CTGF, NOV, WISP1-3) with central roles in development, inflammation, and tissue repair. CCN proteins also exert functions during pathological processes including fibrosis and cancer by regulating extracellular signals in the cellular environment. Studies have demonstrated that all six CCN proteins exert functions in breast tumorigenesis. Although CCN proteins share a multimodular structure in which most cysteine residues are conserved within structural motifs, they may have opposing functions in breast cancer progression. A better understanding of the functions of each CCN member will assist in the development of specific therapeutic approaches for breast cancer.

Emerging roles of CCN proteins in vascular development and pathology

The CCN family of proteins consists of 6 members (CCN1-CCN6) that share conserved functional domains. These matricellular proteins interact with growth factors, extracellular matrix (ECM) proteins, cell surface integrins and other receptors to promote ECM-intracellular signaling. This signaling leads to propagation of a variety of cellular actions, including adhesion, invasion, migration and proliferation within several cell types, including epithelial, endothelial and smooth muscle cells. Though CCNs share significant homology, the function of each is unique due to distinct and cell specific expression patterns. Thus, their correct spatial and temporal expressions are critical during embryonic development, wound healing, angiogenesis and fibrosis. Disruption of these patterns leads to severe development disorders and contributes to the pathological progression of cancers, vascular diseases and chronic inflammatory diseases such as colitis, rheumatoid arthritis and atherosclerosis. While the effects of CCNs are diverse, this review will focus on the role of CCNs within the vasculature during development and in vascular diseases.

WISP-1 a novel angiogenic regulator of the CCN family promotes oral squamous cell carcinoma angiogenesis through VEGF-A expression

Oral squamous cell carcinoma (OSCC), which accounts for nearly 90% of head and neck cancers, is characterized by poor prognosis and a low survival rate. VEGF-A is the most established angiogenic factor involved in the angiogenic-regulated tumor progression. WISP-1/CCN4 is an extracellular matrix-related protein that belongs to the Cyr61, CTGF, Nov (CCN) family and regulates many biological functions, such as angiogenesis. Previous studies indicated the role of WISP-1 in tumor progression. However, the angiogenic property of WISP-1 in the cancer microenvironment has never been discussed. Here, we provide novel insights regarding the role of WISP-1 in the angiogenesis through promoting VEGF-A expression. In this study, the correlation of WISP-1 and VEGF-A was confirmed by IHC staining of specimens from patients with OSCC. In vitro results indicated that WISP-1 induced VEGF-A expression via the integrin αvβ3/FAK/c-Src pathway, which transactivates the EGFR/ERK/HIF1-α signaling pathway in OSCC. This pathway in turn induces the recruitment of endothelial progenitor cells and triggers the neovascularization in the tumor microenvironment. Our in vivo data revealed that tumor-secreted WISP-1 promoted the angiogenesis through VRGF expression and increased angiogenesis-related tumor growth. Our study offers new information that highlights WISP-1 as a potential novel therapeutic target for OSCC.

Emerging role of CCN family proteins in tumorigenesis and cancer metastasis (Review)

The CCN family of proteins comprises the members CCN1, CCN2, CCN3, CCN4, CCN5 and CCN6. They share four evolutionarily conserved functional domains, and usually interact with various cytokines to elicit different biological functions including cell proliferation, adhesion, invasion, migration, embryonic development, angiogenesis, wound healing, fibrosis and inflammation through a variety of signalling pathways. In the past two decades, emerging functions for the CCN proteins (CCNs) have been identified in various types of cancer. Perturbed expression of CCNs has been observed in a variety of malignancies. The aberrant expression of certain CCNs is associated with disease progression and poor prognosis. Insight into the detailed mechanisms involved in CCN-mediated regulation may be useful in understanding their roles and functions in tumorigenesis and cancer metastasis. In this review, we briefly introduced the functions of CCNs, especially in cancer.

Role of WISP3 siRNA in proliferation, apoptosis and invasion of bladder cancer cells

Bladder cancer (BC) is the most common cancers of the urinary tract worldwide, killing thousands of people a year. WISP3 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of proteins. Increasing evidences have linked abnormal levels of CCN family members to tumorigenic effects. In the present study, we found that WISP3 was overexpressed in BC. Knockdown of WISP3by RNA interference in two BC cell lines (5367 and SCaBER cells) significantly inhibited cell proliferation, which may be mediated by cell cycle arrest in G1 phase. Moreover, silencing of WISP3 also induced cell apoptosis via increasing the expression of caspase 3 and caspase 9. Depletion of WISP3 notably inhibited the invasion of BC cells. Our data suggests that inhibition of WISP3 may be a therapeutic strategy for BC.

Nephroblastoma overexpressed gene (NOV) enhances RCC cell motility through upregulation of ICAM-1 and COX-2 expression via Akt pathway

Renal cell carcinoma (RCC) carries a high risk of malignancy and metastasis. The inducible isoform of prostaglandin synthase, cyclooxygenase (COX)-2, and ICAM-1 may be involved in tumor metastasis. CCN3, also called nephroblastoma overexpressed gene (NOV), has been found to regulate the proliferation and differentiation of cancer cells. The effects of NOV on RCC cell migration and expression of COX-2 and ICAM-1 have not described yet in detail. But here, NOV was found to promote the migration and expression of COX-2 and ICAM-1 in human RCC cells. Akt inhibitor was found to interfere with this NOV-induced migration and up-regulation of COX-2 and ICAM-1 in RCC cells. NOV stimulation was here found to promote the phosphorylation of Akt. RCC tissue chips were subjected to IHC staining, which showed COX-2 expression in RCC tissues to be a significantly closely correlated with NOV expression, with significance determined using Pearson correlation testing (P < 0.05). The results of the current work indicate that NOV activates COX-2 and ICAM-1 through Akt, promoting the migration of RCC cells.

Silencing of WISP3 suppresses gastric cancer cell proliferation and metastasis and inhibits Wnt/β-catenin signaling

CCN6/Wnt1-inducible signaling protein-3 (CCN6/WISP3) is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matricellular proteins, which are often dysregulated in cancers. However, the functional role and clinical significance of WISP3 in gastric cancer remain unclear. In this study, we found that silencing of WISP3 suppressed gastric cancer cell proliferation, migration and invasion. Cell adhesion to collagens (collagen I and IV), but not to fibronectin, were significantly inhibited by silencing of WISP3. Furthermore, silencing of WISP3 prevented β-catenin transferring from cell cytoplasm to nuclear, and suppressed canonical Wnt/β-catenin signaling and its downstream target genes, cyclin D1 and TCF-4. By immunohistochemical analysis of 379 patients, we found that the expression of WISP3 is closely associated with gastric cancer size and tumor invasion, and indicates a poor prognosis in both test cohort (253 patients) and validation cohort (126 patients). Moreover, the expression of WISP3 was positively correlated with the expression of cyclin D1 and TCF-4 in gastric cancer tissues. Taken together, our data suggests that WISP3 might be a promising prognostic factor and WISP3-Wnt/β-catenin axis may be a new therapeutic target for the intervention of gastric cancer growth and metastasis.

NOV is upregulated and promotes migration and invasion in bladder cancer

NOV is pro-tumourigenic via epithelial-mesenchymal transition (EMT) in several malignancies but is not studied in bladder cancer (BCa). Whether NOV is responsible for bladder carcinogenesis and the underlying mechanism is unclear. Using immunohistochemical staining, we quantified expressions of NOV, pS6, Vimentin and E-cadherin in 66 bladder cancer and 10 normal bladder urothelium samples. EMT was profiled by EMT index (EMTi) calculated as the ratio of Vimentin to E-cadherin. In vitro and in vivo studies were carried out to profile the role of NOV in the tumourigenesis of BCa. NOV was upregulated in bladder cancer compared to normal tissue, and its expression was correlated to pS6 and EMTi. Expression of NOV was higher in recurrent and multiple tumours and was increased with progression of tumour grade. NOV expression was also higher in BCa cell lines. Silence of NOV attenuated EMT, decreased invasion and migration of BCa cells. Silence of NOV also inhibited xenograft tumour growth and decreased tumour EMT. NOV is pro-tumourigenic in bladder cancer especially in nonmuscle-invasive entities (NMIBC). NOV may promote carcinogenesis via promotion of EMT and association with increased mTOR activity.

NOV promoted the growth and migration of pancreatic cancer cells

NOV, a member of the CCN (Cyr61, CTGF and NOV) family, is involved in diverse biological processes, such as cell adhesion, proliferation and angiogenesis. However, its function in pancreatic cancer remains poorly understood. Here, we found that the expression of NOV was up-regulated in pancreatic cancer tissues. Moreover, over-expression of NOV in pancreatic cancer cells promoted cell proliferation and migration, while knock down the expression of NOV impaired the tumorigenecity of pancreatic cancer cells in vitro and in vivo. Mechanistically, NOV induced epithelial-mesenchymal transition (EMT) and regulated the expression of multiple EMT marker. Taken together, our study suggested the important role of NOV in pancreatic cancer and NOV might be an important therapeutic target.

Apoptosis signal-regulating kinase 1 is involved in WISP-1-promoted cell motility in human oral squamous cell carcinoma cells

Oral squamous cell carcinoma (OSCC) has a tendency to migrate and metastasize. WNT1-inducible signaling pathway protein 1 (WISP-1) is a cysteine-rich protein that belongs to the Cyr61, CTGF, Nov (CCN) family of matrix cellular proteins. The effect of WISP-1 on human OSCC cells, however, is unknown. Here, we showed that WISP-1 increased cell migration and intercellular adhesion molecule-1 (ICAM-1) expression in OSCC cells. Pretreatment of cells with integrin αvβ3 monoclonal antibody (mAb) significantly abolished WISP-1–induced cell migration and ICAM-1 expression. On the other hand, WISP-1–mediated cell motility and ICAM-1 upregulation were attenuated by ASK1, JNK, and p38 inhibitor. Furthermore, WISP-1 also enhanced activator protein 1 (AP-1) activation, and the integrin αvβ3 mAb, and ASK1, JNK, and p38 inhibitors reduced WISP-1–mediated AP-1 activation. Moreover, WISP-1 and ICAM-1 expression correlated with the tumor stage of patients with OSCC. Our results indicate that WISP-1 enhances the migration of OSCC cells by increasing ICAM-1 expression through the αvβ3 integrin receptor and the ASK1, JNK/p38, and AP-1 signal transduction pathways.

A Wisp3 Cre-knockin allele produces efficient recombination in spermatocytes during early prophase of meiosis I

Individuals with the autosomal recessive skeletal disorder Progressive Pseudorheumatoid Dysplasia have loss-of-function mutations in WISP3, and aberrant WISP3 expression has been detected in tumors from patients with colon and breast cancer. In mice however, neither absence nor over-expression of WISP3 was found to cause a phenotype, and endogenous Wisp3 expression has been difficult to detect. To confirm that Wisp3 knockout mice have no phenotype and to identify potential sites of endogenous Wisp3 expression, we generated mice with a knockin allele (Wisp3 (GFP-Cre)) designed to express Green Fluorescent Protein (GFP) and Cre-recombinase instead of WISP3. Heterozygous and homozygous knockin mice were fertile and indistinguishable from their wild-type littermates, confirming that mice lacking Wisp3 have no phenotype. We could not detect GFP-expression from the knockin allele, but we could detect Cre-expression after crossing mice with the knockin allele to Cre-reporter mice; the double heterozygous offspring had evidence of Cre-mediated recombination in several tissues. The only tissue that had high levels of Cre-mediated recombination was the testis, where recombination in spermatocytes occurred by early prophase of meiosis I. As a consequence, males that were double heterozygous for a Wisp3 (GFP-Cre) and a floxed allele only contributed a recombined allele to their offspring. We detected no evidence of Cre-mediated recombination in the female ovary, although when double heterozygous females contributed the reporter allele to their offspring it had recombined ~7% of the time. Wisp3 (GFP-Cre) expression therefore occurs less frequently and most likely at a later stage of oocyte development in female mice compared to male mice. We conclude that although WISP3 is dispensable in mice, male mice with a Wisp3 (GFP-Cre) allele (Jackson Laboratory stock # 017685) will be useful for studying early prophase of meiosis I and for efficiently recombining floxed alleles that are passed to offspring.

CCN6 knockdown disrupts acinar organization of breast cells in three-dimensional cultures through up-regulation of type III TGF-β receptor

While normal cells in the human breast are organized into acinar structures, disruption of the acinar architecture is a hallmark of cancer. In a three-dimensional model of morphogenesis, we show that down-regulation of the matrix-associated tumor suppressor protein CCN6 (WNT1-inducible-signaling pathway protein 3) disrupts breast epithelial cell polarity and organization into acini through up-regulation of the type III transforming growth factor-β receptor (TβRIII or betaglycan). Down-regulation of CCN6 in benign breast cells led to loss of tissue polarity and resulted in cellular disorganization with loss of α6 integrin-rich basement membrane and the basolateral polarity protein E-cadherin. Silencing of TβRIII with shRNA and siRNA rescued the ability of breast epithelial cells to form polarized acinar structures with reduced matrix invasion and restored the correct expression of α6 integrin and E-cadherin. Conversely, CCN6 overexpression in aggressive breast cancer cells reduced TβRIII in vitro and in a xenograft model of CCN6 overexpression. The relevance of our studies to human breast cancer is highlighted by the finding that CCN6 protein levels are inversely associated with TβRIII protein in 64%of invasive breast carcinomas. These results reveal a novel function of the matricellular protein CCN6 and establish a mechanistic link between CCN6 and TβRIII in maintaining acinar organization in the breast.

EZH2 inhibition decreases p38 signaling and suppresses breast cancer motility and metastasis

EZH2 is a Polycomb group protein that exerts oncogenic functions in breast cancer, where its overexpression is associated with metastatic disease. While it reportedly acts a transcriptional repressor through trimethylation of histone H3 at lysine 27, EZH2 may exhibit context-dependent activating functions. Despite associations with worse outcome and metastasis in breast cancer, a functional role of EZH2 in breast cancer metastasis in vivo has not been demonstrated. Furthermore, whether EZH2 regulates cancer cell phenotype and motility are unknown. In this study, we discovered that knockdown of EZH2 induces a phenotypic reprogramming from mesenchymal to epithelial, reduces motility, and blocks invasion in breast cancer cell lines. In vivo, EZH2 downregulation in MDA-MB-231 cells decreases spontaneous metastasis to the lungs. We uncover an unexpected role of EZH2 in inducing the p38 mitogen-activated protein kinase signaling pathway, an important regulator of breast cancer invasion and metastasis. In breast cancer cells, EZH2 binds to phosphorylated p38 (p-p38) in association with other core members of the Polycomb repressive complex 2, EED, and SUZ12, and EZH2 overexpression leads to increased levels of p-p38 and of activated, downstream pathway proteins. The effect on p-p38 was confirmed in vivo, where it correlated with decreased spontaneous metastasis. In clinical specimens of matched primary and invasive breast carcinomas, we found that EZH2 expression was upregulated in 100 % of the metastases, and that EZH2 and p-p38 were coexpressed in 63 % of cases, consistent with the functional results. Together our findings reveal a new mechanism by which EZH2 functions in breast cancer, and provide direct evidence that EZH2 inhibition reduces breast cancer metastasis in vivo.

WISP3-IGF1 interaction regulates chondrocyte hypertrophy

WISP3 (Wnt induced secreted protein 3) is a multi-domain protein of mesenchymal origin. Mutations in several domains of WISP3 cause PPRD (progressive pseudo rheumatoid dysplasia), which is associated with cartilage loss and restricted skeletal development. Despite several studies focusing on the functional characterization of WISP3, the molecular details underlying the course of PPRD remain unresolved. We are interested in analyzing the function of WISP3 in the context of cartilage integrity. The current study demonstrates that WISP3 binds to insulin-like growth factor 1 (IGF1) and inhibits IGF1 secretion. Additionally, WISP3 curbs IGF1-mediated collagen X expression, accumulation of reactive oxygen species (ROS) and alkaline phosphatase activity, all of which are associated with the induction of chondrocyte hypertrophy. Interestingly, both IGF1 and ROS in turn trigger an increase in WISP3 expression. Together, our results are indicative of an operational WISP3-IGF1 regulatory loop whereby WISP3 preserves cartilage integrity by restricting IGF1-mediated hypertrophic changes in chondrocytes, at least partly, upon interaction with IGF1.

CCN6 modulates BMP signaling via the Smad-independent TAK1/p38 pathway, acting to suppress metastasis of breast cancer

CCN6 (WISP3) is an extracellular matrix protein that exerts tumor suppressive functions in breast cancer, where its decreased expression is a feature of advanced disease. However, neither its role nor mechanism of action in breast cancer metastasis has been established. Bone morphogenetic proteins (BMPs), which constitute ligands of the TGF-β superfamily, are multifunctional cytokines that induce epithelial-mesenchymal transition, cell invasion, and metastasis. In this study, we identify a CCN6-BMP4-TAK1 kinase signaling pathway that controls the ability of the p38 MAP kinase to regulate acinar morphogenesis and invasion of breast cells. ShRNA-mediated attenuation of CCN6 in human mammary epithelial cells led to BMP4 upregulation as a major response to exposure to the TGF-β superfamily. CCN6 attenuation also induced BMP4-mediated activation of the Smad-independent TAK1 and p38 kinases. Conversely, ectopic expression of CCN6 in breast cancer cells antagonized BMP4-mediated TAK1/p38 activation and invasive capacity, both by binding BMP4 protein as well as decreasing BMP4 protein levels. Effects on BMP4 and p38 were confirmed in vivo where they correlated with decreased metastasis. In clinical specimens, we found that CCN6 expression was inversely associated with BMP4 and phospho-p38 levels in 69% of invasive breast carcinomas examined, consistent with the functional results. Together our findings identify a novel modifier pathway through which CCN6 acts to limit breast cancer invasion and metastasis.

CCN6 enhances ICAM-1 expression and cell motility in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. CCN6 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, and Nov) family of matricellular proteins. However, the effects of CCN6 on human chondrosarcoma cells are largely unknown. In this study, we found that CCN6 increased the migration and the expression of intercellular adhesion molecule-1 (ICAM-1) in human chondrosarcoma cells. αvβ3 and αvβ5 integrin monoclonal antibody and mitogen-activated protein kinase (MEK) inhibitors (PD98059 and U0126) inhibited the CCN6-induced increase of the migration and ICAM-1 up-regulation of chondrosarcoma cells. CCN6 stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK, and extracellular signal-regulated kinase (ERK). In addition, activator protein-1 (AP-1) inhibitors suppressed the cell migration and ICAM-1 expression enhanced by CCN6. Moreover, CCN6 increased AP-1 luciferase activity and binding of c-Jun to the AP-1 element on the ICAM-1 promoter. Taken together, our results indicate that CCN6 enhances the migration of chondrosarcoma cells by increasing ICAM-1 expression through the αvβ3 and αvβ5 integrin receptor, FAK, MEK, ERK, c-Jun, and AP-1 signal transduction pathway.

CCN3 increases cell motility and MMP-13 expression in human chondrosarcoma through integrin-dependent pathway

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. CCN3, also called nephroblastoma overexpressed gene (NOV), regulates proliferation and differentiation of cancer cells. However, the effect of CCN3 on migration activity in human chondrosarcoma cells is mostly unknown. Here, we found that CCN3 increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). αvβ3 or αvβ5 monoclonal antibody (mAb), phosphatidylinositol 3-kinase (PI3K) inhibitors (Ly294002 and wortmannin) and Akt inhibitor inhibited the CCN3-induced increase of the migration and MMP-13 upregulation of chondrosarcoma cells. CCN3 stimulation increased the phosphorylation of focal adhesion kinase (FAK), PI3K, and Akt. In addition, NF-κB inhibitors also suppressed the cell migration and MMP-13 expression enhanced by CCN3. Moreover, CCN3 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-13 promoter. Taken together, our results indicate that CCN3 enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the αvβ3/αvβ5 integrin receptor, FAK, PI3K, Akt, p65, and NF-κB signal transduction pathway.

On how CCN6 suppresses breast cancer growth and invasion

Living cells communicate with their microenvironment and exchange information through signaling pathways in order to carry out most biological processes. The CCN family of proteins has the ability to coordinate the extracellular and intracellular signaling pathways and epithelial-stromal cross-talks. CCN proteins have been shown to play roles in multiple processes including cancer, either as tumor suppressors or oncogenes. Particularly, loss of CCN6 expression has been reported in highly aggressive breast cancer types, especially in inflammatory breast cancer and breast cancer with axillary lymph node metastasis. Recent findings can better explain the biological relevance of CCN6 as a tumor suppressor protein in breast tumorigenesis. CCN6 loss triggers the process of epithelial to mesenchymal transition (EMT), which converts epithelial cells into migratory and invasive mesenchymal-like cells at least in part through modulation of IGF-1 receptor signaling pathway. Emerging data support the hypothesis that CCN6 also exerts growth factor independent functions, especially related to cell survival and anoikis resistance. Thus, our work provides new insights into the functions and mechanisms of tumor suppression exerted by CCN6 in the breast.

CCN6 (WISP3) decreases ZEB1-mediated EMT and invasion by attenuation of IGF-1 receptor signaling in breast cancer

During progression of breast cancer, CCN6 protein exerts tumor inhibitory functions. CCN6 is a secreted protein that modulates the insulin-like growth factor-1 (IGF-1) signaling pathway. Knockdown of CCN6 in benign mammary epithelial cells triggers an epithelial to mesenchymal transition (EMT), with upregulation of the transcription factor ZEB1/δEF1. How CCN6 regulates ZEB1 expression is unknown. We hypothesized that CCN6 might regulate ZEB1, EMT and breast cancer invasion by modulating IGF-1 signaling. Exogenously added human recombinant CCN6 protein was sufficient to downregulate ZEB1 mRNA and protein levels in CCN6-deficient (CCN6 KD) HME cells and MDA-MB-231 breast cancer cells. Recombinant CCN6 protein decreased invasion of CCN6 KD cells compared with controls. We discovered that knockdown of CCN6 induced IGF-1 secretion in HME cells cultivated in serum-free medium to higher concentrations than found in MDA-MB-231 cells. Treatment with recombinant CCN6 protein was sufficient to decrease IGF-1 protein and mRNA to control levels, rescuing the effect of CCN6 knockdown. Specific inhibition of IGF-1 receptors using the pharmacological inhibitor NVP-AE541 or short hairpin shRNAs revealed that ZEB1 upregulation due to knockdown of CCN6 requires activation of IGF-1 receptor signaling. Recombinant CCN6 blunted IGF-1-induced ZEB1 upregulation in MDA-MB-231 cells. Our data define a pathway in which CCN6 attenuates IGF-1 signaling to decrease ZEB1 expression and invasion in breast cancer. These results suggest that CCN6 could be a target to prevent or halt breast cancer invasion.

WISP-1 increases MMP-2 expression and cell motility in human chondrosarcoma cells

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. WISP-1 is a cysteine-rich protein that belongs to the CCN (Cyr61, CTGF, Nov) family of matricellular proteins. However, the effect of WISP-1 on migration activity in human chondrosarcoma cells is mostly unknown. Here we found that WISP-1 increased the migration and expression of matrix metalloproteinase (MMP)-2 in human chondrosarcoma cells (JJ012 cells). We also found that human chondrosarcoma tissues had significant expression of the WISP-1 which was higher than that in normal cartilage. α5β1 monoclonal antibody and MAPK kinase (MEK) inhibitors (PD98059 and U0126) inhibited the WISP-1-induced increase of the migration and MMP-2 up-regulation of chondrosarcoma cells. WISP-1 stimulation increased the phosphorylation of focal adhesion kinase (FAK), MEK and extracellular signal-regulated kinase (ERK). In addition, NF-κB inhibitors also suppressed the cell migration and MMP-2 expression enhanced by WISP-1. Moreover, WISP-1 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-2 promoter. Taken together, our results indicated that WISP-1 enhances the migration of chondrosarcoma cells by increasing MMP-2 expression through the α5β1 integrin receptor, FAK, MEK, ERK, p65 and NF-κB signal transduction pathway.

High-resolution comparative genomic hybridization of inflammatory breast cancer and identification of candidate genes

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive form of BC poorly defined at the molecular level. We compared the molecular portraits of 63 IBC and 134 non-IBC (nIBC) clinical samples.

METHODOLOGY/FINDINGS

Genomic imbalances of 49 IBCs and 124 nIBCs were determined using high-resolution array-comparative genomic hybridization, and mRNA expression profiles of 197 samples using whole-genome microarrays. Genomic profiles of IBCs were as heterogeneous as those of nIBCs, and globally relatively close. However, IBCs showed more frequent "complex" patterns and a higher percentage of genes with CNAs per sample. The number of altered regions was similar in both types, although some regions were altered more frequently and/or with higher amplitude in IBCs. Many genes were similarly altered in both types; however, more genes displayed recurrent amplifications in IBCs. The percentage of genes whose mRNA expression correlated with CNAs was similar in both types for the gained genes, but ∼7-fold lower in IBCs for the lost genes. Integrated analysis identified 24 potential candidate IBC-specific genes. Their combined expression accurately distinguished IBCs and nIBCS in an independent validation set, and retained an independent prognostic value in a series of 1,781 nIBCs, reinforcing the hypothesis for a link with IBC aggressiveness. Consistent with the hyperproliferative and invasive phenotype of IBC these genes are notably involved in protein translation, cell cycle, RNA processing and transcription, metabolism, and cell migration.

CONCLUSIONS

Our results suggest a higher genomic instability of IBC. We established the first repertory of DNA copy number alterations in this tumor, and provided a list of genes that may contribute to its aggressiveness and represent novel therapeutic targets.

[Expressions of Cyr61 and WISP-3 in non-small cell lung cancer and its clinical significance]

背景与目的

Cyr61是非小细胞肺癌（non-small cell lung cancer, NSCLC）生长过程中的一个肿瘤抑制基因，Cyr61与WISP-3同属于CCN基因家族，具有极其明显的序列同源性。本研究通过检测Cyr61和WISP-3在NSCLC组织中的表达，探讨其临床意义。

方法

应用免疫组化SP染色法检测54例NSCLC癌组织和癌旁正常肺组织中Cyr61和WISP-3的表达，并结合临床参数进行分析。

结果

在NSCLC癌组织中Cyr61表达水平低于癌旁正常肺组织（P < 0.001），WISP-3表达水平高于癌旁正常肺组织（P < 0.001）；NSCLC癌组织中Cyr61与WISP-3蛋白表达呈负相关（r=-0.395, P=0.003）；Cyr61的表达与肿瘤的组织学分化程度、病理类型、临床分期、家族史、吸烟史和淋巴结转移有关（P < 0.05）；WISP-3阳性表达率与肿瘤的组织学分化程度、临床分期和年龄有关（P < 0.05）。

结论

Cyr61和WISP-3可能是反映NSCLC进展、生物学行为、转移发生及预后的重要生物学标记物。

Nephroblastoma overexpressed gene (NOV) enhances cell motility and COX-2 upregulation of human osteosarcoma involves αvβ5 integrin, ILK and AP-1-dependent pathways

Osteosarcoma is characterized by a high malignant and metastatic potential. Cyclooxygenase (COX)-2, the inducible isoform of prostaglandin synthase, has been implicated in tumor metastasis. Nephroblastoma overexpressed gene (NOV), also called CCN3, was regulated proliferation and differentiation of cancer cells. However, the effect of NOV on migration activity and COX-2 expression in human osteosarcoma cells is mostly unknown. Here we found that NOV increased the migration and expression of COX-2 in human osteosarcoma cells. αvβ5 monoclonal antibody (mAb), integrin-linked kinase (ILK) and Akt inhibitor reduced the NOV-enhanced the migration and COX-2 up-regulation of osteosarcoma cells. NOV stimulation increased the ILK kinase activity and phosphorylation of Akt. In addition, c-Jun siRNA also antagonized the NOV-mediated migration and COX-2 expression. Moreover, NOV enhanced the AP-1 binding activity and promoter activity. Taken together, these results suggest that the NOV acts through αvβ5 integrin to activate ILK and Akt, which in turn activates c-Jun and AP-1, resulting in the activations of COX-2 and contributing the migration of human osteosarcoma cells.

Inflammatory breast cancer: the disease, the biology, the treatment

Inflammatory breast cancer (IBC) is a rare and aggressive form of invasive breast cancer accounting for 2.5% of all breast cancer cases. It is characterized by rapid progression, local and distant metastases, younger age of onset, and lower overall survival compared with other breast cancers. Historically, IBC is a lethal disease with less than a 5% survival rate beyond 5 years when treated with surgery or radiation therapy. Because of its rarity, IBC is often misdiagnosed as mastitis or generalized dermatitis. This review examines IBC's unique clinical presentation, pathology, epidemiology, imaging, and biology and details current multidisciplinary management of the disease, which comprises systemic therapy, surgery, and radiation therapy.

Gene expression profiling of inflammatory breast cancer

BACKGROUND

Inflammatory breast cancer (IBC) is a rare but aggressive form of breast cancer. Despite multimodality treatment, the long-term survival rate for patients with IBC has remained inferior at 50%. Until recently, IBC was understudied at the molecular level. Since 2004, new high-throughput molecular profiling technologies have been applied to clinical samples with the aim of identifying genes or pathways potentially involved in disease development that may represent new, clinically relevant targets.

METHODS

The authors conducted gene expression profiling studies of IBC clinical samples and investigated issues that may be addressed in the future to allow the "omics" approach to reach its full potential in IBC.

RESULTS

Starting in December 2004, 6 research groups compared the expression profiles of IBC samples and non-IBC samples. The series of samples were small (37 IBCs for the largest study) and heterogeneous (various tumor selection criteria and technologic platforms were used). The results indicated the feasibility of messenger RNA expression profiling from IBC biopsies, and they demonstrated the great transcriptional heterogeneity of IBC and the existence of molecular subtypes similar to non-IBC that more frequently were basal and positive for ERBB2. Supervised analyses demonstrated differences in gene expression levels between the IBC and non-IBC variable across studies with sometimes no or very subtle differences and, to date, no gene overlap across the reported signatures. No signature predictive of therapeutic response or clinical outcome has been reliably identified or validated.

CONCLUSIONS

Because of the great heterogeneity of IBC, future studies will have to include larger series of IBC samples that are selected using homogeneous criteria. This calls for urgent international collaborations.

The CCN proteins: important signaling mediators in stem cell differentiation and tumorigenesis

The CCN proteins contain six members, namely CCN1 to CCN6, which are small secreted cysteine-rich proteins. The CCN proteins are modular proteins, containing up to four functional domains. Many of the CCN members are induced by growth factors, cytokines, or cellular stress. The CCNs show a wide and highly variable expression pattern in adult and in embryonic tissues. The CCN proteins can integrate and modulate the signals of integrins, BMPs, VEGF, Wnts, and Notch. The involvement of integrins in mediating CCN signaling may provide diverse context-dependent responses in distinct cell types. CCN1 and CCN2 play an important role in development, angiogenesis and cell adhesion, whereas CCN3 is critical to skeletal and cardiac development. CCN4, CCN5 and CCN6 usually inhibit cell growth. Mutations of Ccn6 are associated with the progressive pseudorheumatoid dysplasia and spondyloepiphyseal dysplasia tarda. In stem cell differentiation, CCN1, CCN2, and CCN3 play a principal role in osteogenesis, chondrogenesis, and angiogenesis. Elevated expression of CCN1 is associated with more aggressive phenotypes of human cancer, while the roles of CCN2 and CCN3 in tumorigenesis are tumor type-dependent. CCN4, CCN5 and CCN6 function as tumor suppressors. Although CCN proteins may play important roles in fine-tuning other major signaling pathways, the precise function and mechanism of action of these proteins remain undefined. Understanding of the biological functions of the CCN proteins would not only provide insight into their roles in numerous cellular processes but also offer opportunities for developing therapeutics by targeting CCN functions.

Blockade of CCN6 (WISP3) activates growth factor-independent survival and resistance to anoikis in human mammary epithelial cells

CCN6 is a secreted cysteine-rich matricellular protein (36.9 kDa) that exerts growth-inhibitory functions in breast cancer. Reduction or loss of CCN6 protein has been reported in invasive carcinomas of the breast with lymph node metastasis and in inflammatory breast cancer. However, the mechanism by which CCN6 loss promotes breast cancer growth remains to be defined. In the present study, we developed lentiviral-mediated short hairpin RNA CCN6 knockdown (KD) in nontumorigenic mammary epithelial cells MCF10A and HME. We discovered that CCN6 KD protects mammary epithelial cells from apoptosis and activates growth factor-independent survival. In the absence of exogenous growth factors, CCN6 KD was able to promote growth under anchorage-independent conditions and triggered resistance to detachment-induced cell death (anoikis). On serum starvation, CCN6 KD was sufficient for activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Growth factor-independent cell survival was stunted in CCN6 KD cells when treated with either human recombinant CCN6 protein or the PI3K inhibitor LY294002. Targeted inhibition of Akt isoforms revealed that the survival advantage rendered by CCN6 KD requires specific activation of Akt-1. The relevance of our studies to human breast cancer is highlighted by the finding that low CCN6 protein levels are associated with upregulated expression of phospho-Akt-1 (Ser(473)) in 21% of invasive breast carcinomas. These results enable us to pinpoint one mechanism by which CCN6 controls survival of breast cells mediated by the PI3K/Akt-1 pathway.

Inflammatory breast cancer: novel preoperative therapies

The treatment of inflammatory breast cancer (IBC) has been hampered by the diagnostic rarity of the disease and its consequent inclusion in clinical trials of preoperative treatment for the more indolent locally advanced breast cancer (LABC). Patients with IBC have a 2-fold greater probability of dying of their disease compared with patients diagnosed with LABC. The aggressive clinical portrait of IBC supports the recent investigative focus on determining molecular changes specific to IBC and developing novel systemic therapies that will favorably affect its poor disease prognosis. A significant amount of laboratory research has been involved in defining a specific "inflammatory signature" for IBC, denoting molecular changes consistently found in IBC. This work has involved human IBC tissue and cell lines and has demonstrated overexpression of several molecules governing metastatic dissemination, such as overexpression of E-cadherin concurrent with a dysfunctional mucin 1. An increased prevalence of mutant TP53, overexpression of RhoC, and vascular endothelial growth factor-A has been found to contribute to the dominant influence of angiogenesis in this disease. A greater understanding of the molecular mechanisms governing the pathophysiology of IBC has led to the development and clinical application of novel targeting agents for preoperative therapy. This study reviews the advances in molecular understanding of IBC and focuses on the efficacy of therapies that target the epidermal growth factor pathway and angiogenesis as well as early investigational therapies involving RhoC and TP53.