NOV/CCN3 Promotes Cell Migration and Invasion in Intrahepatic Cholangiocarcinoma via miR-92a-3p.

Intrahepatic cholangiocarcinoma (ICC) is a common type of human cancer with a poor prognosis, and investigating the potential molecular mechanisms that can contribute to gene diagnosis and therapy. Herein, based on the recently concerned vertebrate-specific Cyr61/CTGF/NOV (CCN) gene family because of its important roles in diverse diseases, we obtained NOV/CCN3 to query for its potential roles in tumorigenesis via bioinformatics analysis. Experimental validations confirmed that both NOV mRNA and protein are up-regulated in two ICC cell lines, suggesting that it may promote cell migration and invasion by promoting EMT. To elucidate the detailed regulatory mechanism, miR-92a-3p is screened and identified as a negative regulatory small RNA targeting NOV, and further experimental validation demonstrates that miR-92a-3p contributes to NOV-mediated migration and invasion of ICC via the Notch signaling pathway. Our study reveals that NOV may be a potential target for diagnosing and treating ICC, which will provide experimental data and molecular theoretical foundation for cancer treatment, particularly for future precision medicine.

The Emerging Roles of CCN3 Protein in Immune-Related Diseases.

The CCN proteins are a family of extracellular matrix- (ECM-) associated proteins which currently consist of six secreted proteins (CCN1-6). CCN3 protein, also known as nephroblastoma overexpressed protein (NOV), is a member of the CCN family with multiple biological functions, implicated in major cellular processes such as cell growth, migration, and differentiation. Recently, CCN3 has emerged as a critical regulator in a variety of diseases, including immune-related diseases, including rheumatology arthritis, osteoarthritis, and systemic sclerosis. In this review, we will briefly introduce the structure and function of the CCN3 protein and summarize the roles of CCN3 in immune-related diseases, which is essential to understand the functions of the CCN3 in immune-related diseases.

CCN3 Regulates Macrophage Foam Cell Formation and Atherosclerosis.

Recent studies implicate the Cyr61, CTGF, Nov (CCN) matricellular signaling protein family as emerging players in vascular biology, with NOV (alias CCN3) as an important regulator of vascular homeostasis. Herein, we examined the role of CCN3 in the pathogenesis of atherosclerosis. In response to a 15-week high-fat diet feeding, CCN3-deficient mice on the atherosclerosis-prone Apoe-/- background developed increased aortic lipid-rich plaques compared to control Apoe-/- mice, a result that was observed in the absence of alterations in plasma lipid content. To address the cellular contributor(s) responsible for the atherosclerotic phenotype, we performed bone marrow transplantation experiments. Transplantation of Apoe; Ccn3 double-knockout bone marrow into Apoe-/- mice resulted in an increase of atherosclerotic plaque burden, whereas transplantation of Apoe-/- marrow to Apoe; Ccn3 double-knockout mice caused a reduction of atherosclerosis. These results indicate that CCN3 deficiency, specifically in the bone marrow, plays a major role in the development of atherosclerosis. Mechanistically, cell-based studies in isolated peritoneal macrophages demonstrated that CCN3 deficiency leads to an increase of lipid uptake and foam cell formation, an effect potentially attributed to the increased expression of scavenger receptors CD36 and SRA1, key factors involved in lipoprotein uptake. These results suggest that bone marrow-derived CCN3 is an essential regulator of atherosclerosis and point to a novel role of CCN3 in modulating lipid accumulation within macrophages.

Regulatory T cells promote myelin regeneration in the central nervous system.

Regeneration of CNS myelin involves differentiation of oligodendrocytes from oligodendrocyte progenitor cells. In multiple sclerosis, remyelination can fail despite abundant oligodendrocyte progenitor cells, suggesting impairment of oligodendrocyte differentiation. T cells infiltrate the CNS in multiple sclerosis, yet little is known about T cell functions in remyelination. We report that regulatory T cells (Treg) promote oligodendrocyte differentiation and (re)myelination. Treg-deficient mice exhibited substantially impaired remyelination and oligodendrocyte differentiation, which was rescued by adoptive transfer of Treg. In brain slice cultures, Treg accelerated developmental myelination and remyelination, even in the absence of overt inflammation. Treg directly promoted oligodendrocyte progenitor cell differentiation and myelination in vitro. We identified CCN3 as a Treg-derived mediator of oligodendrocyte differentiation and myelination in vitro. These findings reveal a new regenerative function of Treg in the CNS, distinct from immunomodulation. Although the cells were originally named 'Treg' to reflect immunoregulatory roles, this also captures emerging, regenerative Treg functions.

[CCN3 regulates the proliferation and apoptosis in periodontal ligament fibroblasts].

PURPOSE: To investigate the effect of CCN3 on proliferation and apoptosis in periodontal ligament fibroblasts (PDLFs) and related mechanism. METHODS: Recombinant vector pcDNA.3.1-CCN3 was constructed and transfected into human PDLFs to overexpress CCN3. CCN3 siRNA was transfected to inhibit CCN3. Fra-1 siRNA was transfected into the PDLFs with CCN3 inhibition to realize the inhibition of CCN3 and Fra-1 in the meantime. mRNA expressions of CCN3 and Fra-1 were measured by quantitative real-time PCR (qRT-PCR). The protein expressions of CCN3, Fra-1and Bcl-2 were detected by Western blot. Cell growth and viability and proliferation of PDLFs were measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and bromodeoxyuridine (BrdU) assays; Caspase-3 activity was tested by using the available kit. The data were analyzed with SPSS20.0 software package. RESULTS: The results showed that the mRNA (P<0.05) and protein (P<0.05) expressions of CCN3 were significantly up-regulated in the experimental group of pcDNA.3.1-CCN3 transfection. In addition, the mRNA (P<0.05) and protein (P<0.05) expressions of CCN3 were significantly decreased in the experimental group of CCN3 siRNA transfection. Cell growth (P<0.05) and viability, proliferation (P<0.05) and Bcl-2 (P<0.05) protein expression were increased, while caspase-3 activity (P<0.05) decreased in the PDLFs with CCN3 inhibition. However, CCN3 overexpression exhibited reversed effect. CCN3 overexpression or inhibition could remarkably constrain (P<0.05) or promote (P<0.01) the expression of Fra-1, respectively. Moreover, co-inhibition of CCN3 and Fra-1 could promote apoptosis (P<0.01) and inhibit proliferation (P<0.05) in PDLFs. CONCLUSIONS: The results suggest that inhibition of CCN3 could accelerate proliferation and constrain apoptosis via up-regulating expression of Fra-1 in PDLFs.

Targeted mutation of NOV/CCN3 in mice disrupts joint homeostasis and causes osteoarthritis-like disease.

OBJECTIVE: The matricellular protein NOV/CCN3, is implicated in osteoarthritis (OA) and targeted mutation of NOV in mice (Nov(del3)) leads to joint abnormalities. This investigation tested whether NOV is required for joint homeostasis and if its disruption causes joint degeneration. METHOD: NOV expression in the adult mouse joint was characterized by immunohistochemistry. A detailed comparison of the joints of Nov(del3)-/- and Nov(del3)+/+ (wild-type) males and females at 2, 6 and 12 months of age was determined by X-ray, histology and immunohistochemistry. RESULTS: NOV protein was found in specific cells in articular cartilage, meniscus, synovium and ligament attachment sites in adult knees. Nov(del3)-/- males exhibited severe OA-like pathology at 12 months (OARSI score 5.0 ± 0.5, P < 0.001), affecting all tissues of the joint: erosion of the articular cartilage, meniscal enlargement, osteophytic outgrowths, ligament degeneration and expansion of fibrocartilage. Subchondral sclerosis and changes in extracellular matrix composition consistent with OA, were also seen. The density of articular cartilage cells in Nov(del3)+/+ knee joints is maintained at a constant level from 2 to 12 months of age whereas this is not the case in Nov(del3)-/- mice. Compared with age and sex-matched Nov(del3)+/+ mice, a significant increase in articular cartilage density was seen in Nov(del3)-/- males at 2 months, whereas a significant decrease was seen at 6 and 12 months in both Nov(del3)-/- males and females. CONCLUSION: NOV is required for the maintenance of articular cartilage and for joint homeostasis, with disruption of NOV in ageing Nov(del3)-/- male mice causing OA-like disease.

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.

CCN3 regulates proliferation and migration properties in Jeg3 trophoblast cells via ERK1/2, Akt and Notch signalling.

Previous studies showed that CCN3 is deregulated in early-onset pre-eclampsia (PE), a pregnancy disease associated with impaired trophoblast invasion, which leads to reduced fetal oxygen and nutrition support. Recently, we identified the glycosylated (g-CCN3) and the non-glycosylated (ng-CCN3) form of matricellular CCN3 as key factors in regulation of trophoblast proliferation and invasion. While Jeg3 cells revealed a decreased proliferation upon stimulation with both forms of CCN3, enhanced migration and invasion properties were only found for ng-CCN3. Here, we focused on the signalling cascades mitogen-activated protein kinase (MAPK), PI3 kinase/Akt and Notch/p21 for mediating the dual function of CCN3 on trophoblast proliferation versus migration in Jeg3 cells upon stimulation with g- and ng-recombinant CCN3 (g/ng-rCCN3). Analysis of the CCN3-mediated signalling pathways showed that ng-rCCN3 stimulated migration properties by activating the Akt as well as the MAPK pathway. Moreover, cell migration stimulated by ng-rCCN3 was mediated via Akt and integrin α5ß1 but not the antiproliferative effect of CCN3. There was evidence that the Notch pathway might contribute to the antiproliferative properties of both forms of CCN3 by an increase in Notch1 expression and its target gene, the cell cycle inhibitor p21. Our data showed that the presence of both forms of CCN3 is accompanied by a balance of trophoblast proliferation and migration/invasion properties, which are triggered by different signalling pathways. Thus, a deregulated expression of g/ng-CCN3 could lead to an imbalance in proliferation versus invasion, and might contribute to the shallow trophoblast invasion observed in PE.

The clinical and prognostic significance of CCN3 expression in patients with cervical cancer.

BACKGROUND: CCN3 plays important roles in growth, differentiation, angiogenesis and adhesion. Recently, the role of CCN3 in human carcinogenesis has become an area of great interest. However, little is known about the function of CCN3 in human cervical cancer. OBJECTIVES: The aim of this study was to investigate the expression profile of CCN3 in cervical cancer and to assess its clinical significance. MATERIAL AND METHODS: In this study, qRT-PCR, immunohistochemistry and Western blotting analysis were used in the detection of CCN3 mRNA and protein expression, both in cervical cancer and in corresponding normal tissue, respectively. The data was correlated with clinicopathological features. A survival analysis was performed to assess the prognostic significance. RESULTS: CCN3 mRNA was overexpressed in cervical cancer tissue when compared with corresponding normal tissue, as was CCN3 protein. Upregulation of CCN3 was significantly associated with the stage of the disease (P = 0.017) and with lymph node involvement (P = 0.006). Using the Kaplan-Meier analysis, a comparison of survival curves of low vs. high expressers of CCN3 revealed a highly significant difference in human cervical cancer tissue (P = 0.021), which suggests that overexpression of CCN3 is associated with a poorer prognosis. CONCLUSIONS: The results of the current study suggest that CCN3 may play an important role in cervical carcinogenesis and therefore may have potential as a biomarker for prognosis and as a therapeutic target in cervical cancer.

A novel, dual role of CCN3 in experimental glomerulonephritis: pro-angiogenic and antimesangioproliferative effects.

In contrast to factors that promote mesangial cell proliferation, little is known about their endogenous inhibitors. During experimental mesangioproliferative nephritis, expression of the glomerular CCN3 (nephroblastoma overexpressed gene [NOV]) gene is reduced before the proliferative phase and increased in glomeruli and serum when mesangial cell proliferation subsides. To further elucidate its role in mesangioproliferative glomerulonephritis, CCN3 systemically was overexpressed by muscle electroporation in healthy or nephritic rats. This increased CCN3 serum concentrations more than threefold for up to 56 days. At day 5 after disease induction, CCN3-transfected rats showed an increase in glomerular endothelial area and in mRNA levels of the pro-angiogenic factors vascular endothelial growth factor and PDGF-C. At day 7, CCN3 overexpression decreased mesangial cell proliferation, including expression of α-smooth muscle actin and matrix accumulation of fibronectin and type IV collagen. In progressive nephritis (day 56), overexpression of CCN3 resulted in decreased albuminuria, glomerulosclerosis, and reduced cortical collagen type I accumulation. In healthy rat kidneys, overexpression of CCN3 induced no morphologic changes but regulated glomerular gene transcripts (reduced transcription of PDGF-B, PDGF-D, PDGF-receptor-ß, and fibronectin, and increased PDGF-receptor-α and PDGF-C mRNA). These data identify a dual role for CCN3 in experimental glomerulonephritis with pro-angiogenic and antimesangioproliferative effects. Manipulation of CCN3 may represent a novel approach to help repair glomerular endothelial damage and mesangioproliferative changes.

CCN3 increases cell motility and ICAM-1 expression in prostate cancer cells.

Nephroblastoma overexpressed (NOV or CCN3) is a secreted matrix-associated protein that belongs to the CCN gene family and is involved in many cellular functions, including growth, differentiation and adhesion. The effect of CCN3 on human prostate cancer cells, however, is unknown. Here, we have shown that CCN3 increased cell migration and intercellular adhesion molecule-1 (ICAM-1) expression in prostate cancer cells. In addition, expression of CCN3 was positively correlated with both cell migration and ICAM-1 expression in human prostate cancer cells. CCN3 activated a signal transduction pathway that included αvß3 integrin, integrin-linked kinase (ILK), Akt and nuclear factor-kappaB (NF-κB). Reagents that inhibit specific components of this pathway each diminished the ability of CCN3 to effect cell migration and ICAM-1 expression. Moreover, CCN3 increased binding of p65 to an NF-κB-binding element in the ICAM-1 promoter. Finally, knockdown of CCN3 expression markedly inhibited cell migration, tumor growth in bone and bone metastasis. Taken together, our results indicate that CCN3 enhances the migration of prostate cancer cells by increasing ICAM-1 expression through a signal transduction pathway that involves αvß3 integrin, ILK, Akt and NF-κB. CCN3 thus represents a promising new target for treating prostate cancer.

Nephroblastoma overexpressed gene (NOV) enhances cell motility and COX-2 upregulation of human osteosarcoma involves αvß5 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. αvß5 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 αvß5 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.

Nephroblastoma overexpressed (Nov) inactivation sensitizes osteoblasts to bone morphogenetic protein-2, but nov is dispensable for skeletal homeostasis.

Overexpression of nephroblastoma overexpressed (Nov), a member of the Cyr 61, connective tissue growth factor, Nov family of proteins, inhibits osteoblastogenesis and causes osteopenia. The consequences of Nov inactivation on osteoblastogenesis and the postnatal skeleton are not known. To study the function of Nov, we inactivated Nov by homologous recombination. Nov null mice were maintained in a C57BL/6 genetic background after the removal of the neomycin selection cassette and compared with wild-type controls of identical genetic composition. Nov null mice were identified by genotyping and absent Nov mRNA in calvarial extracts and osteoblast cultures. Nov null mice did not exhibit developmental skeletal abnormalities or postnatal changes in weight, femoral length, body fat, or bone mineral density and appeared normal. Bone volume and trabecular number were decreased only in 1-month-old female mice. In older mice, after 7 months of age, osteoblast surface and bone formation were increased in females, and osteoclast and eroded surfaces were increased in male Nov null mice. Calvarial osteoblasts from Nov null mice displayed enhanced alkaline phosphatase activity, alkaline phosphatase mRNA, and transactivation of a bone morphogenetic protein (BMP)/phosphorylated mothers against decapentaplegic reporter construct in response to BMP-2. Similar results were obtained after the down-regulation of Nov by RNA interference in ST-2 stromal and MC3T3 cells. Osteoclast number was increased in marrow stromal cell cultures from Nov null mice. Surface plasmon resonance demonstrated direct interactions between Nov and BMP-2. In conclusion, Nov sensitizes osteoblasts to BMP-2, but Nov is dispensable for the maintenance of bone mass.

CCN3 (NOV) is a negative regulator of CCN2 (CTGF) and a novel endogenous inhibitor of the fibrotic pathway in an in vitro model of renal disease.

Fibrosis is a major cause of end-stage renal disease, and although initiation factors have been elucidated, uncertainty concerning the downstream pathways has hampered the development of anti-fibrotic therapies. CCN2 (CTGF) functions downstream of transforming growth factor (TGF)-beta, driving increased extracellular matrix (ECM) accumulation and fibrosis. We examined the possibility that CCN3 (NOV), another CCN family member with reported biological activities that differ from CCN2, might act as an endogenous negative regulator of ECM and fibrosis. We show that cultured rat mesangial cells express CCN3 mRNA and protein, and that TGF-beta treatment reduced CCN3 expression levels while increasing CCN2 and collagen type I activities. Conversely, either the addition of CCN3 or CCN3 overexpression produced a marked down-regulation of CCN2 followed by virtual blockade of both collagen type I transcription and its accumulation. This finding occurred in both growth-arrested and CCN3-transfected cells under normal growth conditions after TGF-beta treatment. These effects were not attributable to altered cellular proliferation as determined by cell cycle analysis, nor were they attributable to interference of Smad signaling as shown by analysis of phosphorylated Smad3 levels. In conclusion, both CCN2 and CCN3 appear to act in a yin/yang manner to regulate ECM metabolism. CCN3, acting downstream of TGF-beta to block CCN2 and the up-regulation of ECM, may therefore serve to naturally limit fibrosis in vivo and provide opportunities for novel, endogenous-based therapeutic treatments.

CCN3--a key regulator of the hematopoietic compartment.

CCN3, a founding member of the CCN family of growth regulators, was linked with hematology in 2003(1) when it was detected in human serum. CCN3 is expressed and secreted by hematopoietic progenitor cells in normal bone marrow. CCN3 acts through the core stem cell signalling pathways including Notch and Bone Morphogenic Protein, connecting CCN3 with the modulation of self-renewal and maturation of a number of cell lineages including hematopoietic, osteogenic and chondrogenic. CCN3 expression is disrupted in Chronic Myeloid Leukemia as a consequence of the BCR-ABL oncogene and allows the leukemic clone to evade growth regulation. In contrast, naïve cord blood progenitors undergo enhanced clonal expansion in response to CCN3. Altered CCN3 expression is associated with numerous solid tumors including glioblastoma, melanoma, adrenocortical tumours, prostate cancer and bone malignancies including osteosarcoma. Mature CCN3 protein has five distinct modules and truncated protein variants with altered function are found in many cancers. Regulation by CCN3 is therefore cell type and isoform specific. CCN3 has emerged as a key player in stem cell regulation, hematopoiesis and a crucial component within the bone marrow microenvironment.