Expression of fibrogenic cytokines in desmoplastic malignant melanoma

Combination of Anti-Angiogenics and Immunotherapies in Renal Cell Carcinoma Show Their Limits: Targeting Fibrosis to Break through the Glass Ceiling?

This review explores treating metastatic clear cell renal cell carcinoma (ccRCC) through current therapeutic modalities-anti-angiogenic therapies and immunotherapies. While these approaches represent the forefront, their limitations and variable patient responses highlight the need to comprehend underlying resistance mechanisms. We specifically investigate the role of fibrosis, prevalent in chronic kidney disease, influencing tumour growth and treatment resistance. Our focus extends to unravelling the intricate interplay between fibrosis, immunotherapy resistance, and the tumour microenvironment for effective therapy development. The analysis centres on connective tissue growth factor (CTGF), revealing its multifaceted role in ccRCC-promoting fibrosis, angiogenesis, and cancer progression. We discuss the potential of targeting CTGF to address the problem of fibrosis in ccRCC. Emphasising the crucial relationship between fibrosis and the immune system in ccRCC, we propose that targeting CTGF holds promise for overcoming obstacles to cancer treatment. However, we recognise that an in-depth understanding of the mechanisms and potential limitations is imperative and, therefore, advocate for further research. This is an essential prerequisite for the successful integration of CTGF-targeted therapies into the clinical landscape.

Cathelicidin-3 Associated With Serum Extracellular Vesicles Enables Early Diagnosis of a Transmissible Cancer

The identification of practical early diagnostic biomarkers is a cornerstone of improved prevention and treatment of cancers. Such a case is devil facial tumor disease (DFTD), a highly lethal transmissible cancer afflicting virtually an entire species, the Tasmanian devil (Sarcophilus harrisii). Despite a latent period that can exceed one year, to date DFTD diagnosis requires visual identification of tumor lesions. To enable earlier diagnosis, which is essential for the implementation of effective conservation strategies, we analyzed the extracellular vesicle (EV) proteome of 87 Tasmanian devil serum samples using data-independent acquisition mass spectrometry approaches. The antimicrobial peptide cathelicidin-3 (CATH3), released by innate immune cells, was enriched in serum EV samples of both devils with clinical DFTD (87.9% sensitivity and 94.1% specificity) and devils with latent infection (i.e., collected while overtly healthy, but 3-6 months before subsequent DFTD diagnosis; 93.8% sensitivity and 94.1% specificity). Although high expression of antimicrobial peptides has been mostly related to inflammatory diseases, our results suggest that they can be also used as accurate cancer biomarkers, suggesting a mechanistic role in tumorous processes. This EV-based approach to biomarker discovery is directly applicable to improving understanding and diagnosis of a broad range of diseases in other species, and these findings directly enhance the capacity of conservation strategies to ensure the viability of the imperiled Tasmanian devil population.

Connective tissue growth factor expression hints at aggressive nature of colorectal cancer

BACKGROUND

Connective tissue growth factor (CTGF) is a mediator of transforming growth factor-beta signaling and plays a key role in connective tissue remodeling, inflammatory processes and fibrosis in various illnesses including cancer.

AIM

To investigate the role of CTGF in colorectal cancer (CRC) progression and to compare the CTGF expression with different clinicopathological parameters.

METHODS

Real-time polymerase chain reaction, immunohistochemistry and Western blotting was performed to evaluate the CTGF expression and the results were statistically analyzed against the clinicopathological variables of patient data using STATA software version 16.

RESULTS

CTGF expression levels in tumor specimens were significantly higher than their paired normal specimens. The higher protein expression levels showed a significant association with smoking, staging, tumor grade, invasion depth, necrosis of tumor tissue, and both lymphovascular and perineural invasion. As per the cox regression model and classification tree analysis, tumor-node-metastasis stage and perineural invasion were important predictors for CTGF expression and prognosis of CRC patients. Survival analysis indicated that CTGF overexpression was associated with poorer overall and disease-free survival.

CONCLUSION

Expression of CTGF was increased in CRC and was linked with poor overall and disease-free survival of CRC patients. These findings support prior observations and thus CTGF may be a possible prognostic marker in CRC.

A review: hippo signaling pathway promotes tumor invasion and metastasis by regulating target gene expression

BACKGROUND

The Hippo pathway is widely considered to inhibit cell growth and play an important role in regulating the size of organs. However, recent studies have shown that abnormal regulation of the Hippo pathway can also affect tumor invasion and metastasis. Therefore, finding out how the Hippo pathway promotes tumor development by regulating the expression of target genes provides new ideas for future research on targeted drugs that inhibit tumor progression.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched.

RESULTS

The search strategy identified 1892 hits and 196 publications were finally included in this review. As the core molecule of the Hippo pathway, YAP/TAZ are usually highly expressed in tumors that undergo invasion and migration and are accompanied by abnormally strong nuclear metastasis. Through its interaction with nuclear transcription factors TEADs, it directly or indirectly regulates and the expressions of target genes related to tumor metastasis and invasion. These target genes can induce the formation of invasive pseudopodia in tumor cells, reduce intercellular adhesion, degrade extracellular matrix (ECM), and cause epithelial-mesenchymal transition (EMT), or indirectly promote through other signaling pathways, such as mitogen-activated protein kinases (MAPK), TGF/Smad, etc, which facilitate the invasion and metastasis of tumors.

CONCLUSION

This article mainly introduces the research progress of YAP/TAZ which are the core molecules of the Hippo pathway regulating related target genes to promote tumor invasion and metastasis. Focus on the target genes that affect tumor invasion and metastasis, providing the possibility for the selection of clinical drug treatment targets, to provide some help for a more in-depth study of tumor invasion and migration mechanism and the development of clinical drugs.

Activation of cancer-associated fibroblasts is required for tumor neovascularization in a murine model of melanoma

Metastatic melanoma is highly fatal. Within the tumor microenvironment, the role of cancer-associated fibroblasts (CAFs) in melanoma metastasis and progression is relatively understudied. The matricellular protein CCN2 (formerly termed connective tissue growth factor, CTGF) is overexpressed, in a fashion independent of BRAF mutational status, by CAFs in melanoma. Herein, we find, in human melanoma patients, that CCN2 expression negatively correlates with survival and positively correlates with expression of neovascularization markers. To assess the role of CAFs in melanoma progression, we used C57BL/6 mice expressing a tamoxifen-dependent cre recombinase expressed under the control of a fibroblast-specific promoter/enhancer (COL1A2) to delete CCN2 postnatally in fibroblasts. Mice deleted or not for CCN2 in fibroblasts were injected subcutaneously with B16-F10 melanoma cells. Loss of CCN2 in CAFs resulted in reduced CAF activation, as detected by staining with anti-α-smooth muscle actin antibodies, and reduced tumor-induced neovascularization, as detected by micro-computed tomography (micro-CT) and staining with anti-CD31 antibodies. CCN2-deficient B16(F10) cells were defective in a tubule formation/vasculogenic mimicry assay in vitro. Mice deleted for CCN2 in CAFs also showed impaired vasculogenic mimicry of subcutaneously-injected B16-F10 cells in vivo. Our results provide new insights into the cross-talk among different cell types in the tumor microenvironment and suggest CAFs play a heretofore unappreciated role by being essential for tumor neovascularization via the production of CCN2. Our data are consistent with the hypothesis that activated CAFs are essential for melanoma metastasis and that, due to its role in this process, CCN2 is a therapeutic target for melanoma.

Deregulated expression of connective tissue growth factor (CTGF/CCN2) is linked to poor outcome in human cancer

Connective tissue growth factor (CTGF/CCN2) has long been associated with human cancers. The role it plays in these neoplasms is diverse and tumour specific. Recurring patterns in clinical outcome, histological desmoplasia and mechanisms of action have been found. When CTGF is overexpressed compared to low-expressing normal tissue or is underexpressed compared to high-expressing normal tissue, the functional outcome favours tumour survival and disease progression. CTGF acts by altering proliferation, drug resistance, angiogenesis, adhesion and migration contributing to metastasis. The pattern of CTGF expression and tumour response helps to clarify the role of this matricellular protein across a multitude of human cancers.

CCN2 enhances resistance to cisplatin-mediating cell apoptosis in human osteosarcoma

Osteosarcoma (OS) is the most common form of malignant bone tumor and is an aggressive malignant neoplasm exhibiting osteoblastic differentiation. Cisplatin is one of the most efficacious antitumor drugs for osteosarcoma patients. However, treatment failures are common due to the development of chemoresistance. CCN2 (also known as CTGF), is a secreted protein that binds to integrins, modulates the invasive behavior of certain human cancer cells. However, the effect of CCN2 in cisplatin-mediated chemotherapy is still unknown. Here, we found that CCN2 was upregulated in human osteosarcoma cells after treatment with cisplatin. Moreover, overexpression of CCN2 increased the resistance to cisplatin-mediated cell apoptosis. In contrast, reduction of CCN2 by CCN2 shRNA promoted the chemotherapeutic effect of cisplatin. We also found that CCN2 provided resistance to cisplatin-induced apoptosis through upregulation of Bcl-xL and survivin. Knockdown of Bcl-xL or survivin removed the CCN2-mediated resistance to apoptosis induced by cisplatin. On the other hand, CCN2 also promoted FAK, MEK, and ERK survival signaling pathways to enhance tumor survival during cisplatin treatment. In a mouse xenograft model, overexpression of CCN2 promoted resistance to cisplatin. However, knockdown of CCN2 increased the therapeutic effect of cisplatin. Therefore, our data suggest that CCN2 might be a critical oncogene of human osteosarcoma for cisplatin-resistance and supported osteosarcoma cell growth in vivo and in vitro.

Collapsin response mediator proteins: Potential diagnostic and prognostic biomarkers in cancers (Review)

The collapsin response mediator proteins (CRMPs) were originally identified as mediators of semaphorin 3A signaling and neuronal differentiation. The CRMP family consists of five homologous cytosolic proteins, CRMP1-5. Altered expression levels of CRMPs have been observed in several malignant tumors, including lung, breast, colorectal, prostate, pancreatic and neuroendocrine lung cancer. The aim of the current study was to review the recent progress achieved in understanding the association between the different levels of CRMP expression in tumors and their involvement in pathological functions, such as tumor metastasis, disease progression, subtype differentiation and clinical outcome, to address the potential value of CRMPs as biomarkers for the diagnosis and prognosis of cancer patients.

Induction of chemokine receptor CXCR4 expression by transforming growth factor-β1 in human basal cell carcinoma cells

BACKGROUND

Higher CXCR4 expression enhances basal cell carcinoma (BCC) invasion and angiogenesis. The underlying mechanism of increased CXCR4 expression in invasive BCC is still not well understood.

OBJECTIVE

To investigate the mechanisms involved in the regulation of CXCR4 expression in invasive BCC.

METHODS

We used qRT-PCR, RT-PCR, Western blot, and flow cytometric analyses to examine different CXCR4 levels among the clinical samples, co-cultured BCC cells and BCC cells treated with recombinant transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF). Immunohistochemical studies were used to demonstrate the correlation between TGF-β1 and CXCR4 expressions. The signal transduction pathway and transcriptional regulation were confirmed by treatments with chemical inhibitors, neutralizing antibodies, or short interfering RNAs, as well as luciferase reporter activity.

RESULTS

Invasive BCC has higher TGF-β1 and CTGF levels compared to non-invasive BCC. Non-contact dermal fibroblasts co-culture with human BCC cells also increases the expression of CXCR4 in BCC cells. Treatment with recombinant human TGF-β1, but not CTGF, enhanced the CXCR4 levels in time- and dose-dependent manners. The protein level and surface expression of CXCR4 in human BCC cells was increased by TGF-β1 treatment. TGF-β1 was intensely expressed in the surrounding fibroblasts of invasive BCC and was positively correlated with the CXCR4 expression of BCC cells. The transcriptional regulation of CXCR4 by TGF-β1 is mediated by its binding to the TGF-β receptor II and phosphorylation of the extracellular signal-related kinase 1/2 (ERK1/2)-ETS-1 pathway.

CONCLUSION

TGF-β1 induces upregulation of CXCR4 in human BCC cells by phosphorylation of ERK1/2-ETS-1 pathway.

EGFR/TGFα and TGFβ/CTGF Signaling in Neuroendocrine Neoplasia: Theoretical Therapeutic Targets

Neuroendocrine neoplasms (NENs) are a heterogeneous family of malignancies whose proliferation is partially dependent on growth factors secreted by the microenvironment and the tumor itself. Growth factors which were demonstrated to be important in experimental models of NENs include EGF (epidermal growth factor), TGF (transforming growth factor) α, TGFβ and CTGF (connective tissue growth factor). EGF and TGFα bind to the EGF receptor to stimulate an intact RAS/RAF/MAPK pathway, leading to the transcription of genes associated with cell proliferation, invasion and metastasis. Theoretically, TGFα stimulation can be inhibited at several points of the MAPK pathway, but success is limited to NEN models and is not evident in the clinical setting. TGFβ1 stimulates TGFβ receptors (TGFβRI and TGFβRII) resulting in inhibition of neuroendocrine cell growth through SMAD-mediated activation of the growth inhibitor P21(WAF1/CIP1). Although some NENs are inhibited by TGFβ1, paradoxical growth is seen in experimental models of gastric and small intestinal (SI) NENs. Therapeutic targeting of TGFβ1 in NENs is therefore complicated by uncertainty of the effect of TGFβ1 secretion on the direction of proliferative regulation. CTGF expression is associated with more malignant clinical phenotypes in a variety of cancers, including NENs. CTGF promotes growth in gastric and SI-NEN models, and is implicated as a mediator of local and distant fibrosis caused by NENs of enterochromaffin cell origin. CTGF inhibitors are available, but their anti-proliferative effect has not been tested in NENs. In summary, growth factors are essential for NEN proliferation, and although interventions targeting these proteins are effective in experimental models, only limited clinical efficacy has been identified.

Inverse expression of cystein-rich 61 (Cyr61/CCN1) and connective tissue growth factor (CTGF/CCN2) in borderline tumors and carcinomas of the ovary

Members of the CCN [cystein-rich 61 (Cyr61)/connective tissue growth factor (CTGF)/nephroblastoma (NOV)] protein family are involved in the regulation of cellular proliferation, apoptosis, and migration and are also assumed to play a role in carcinogenesis. Therefore, we performed a retrospective study to investigate the immunohistochemical expression of both Cyr61 and CTGF in 92 borderline tumors (BOTs) and 107 invasive carcinomas of the ovary (IOCs). To determine their diagnostic and prognostic value, we correlated protein expression with clinicopathologic factors including overall and disease-free survival. Cyr61 and CTGF were found to be inversely expressed in both BOTs and IOCs, with a stronger expression of Cyr61 in IOCs. Moreover, Cyr61 was found to be preferentially expressed in high-grade serous carcinomas, whereas CTGF was found more frequently in low-grade serous carcinomas. Weak Cyr61 levels correlated with both low estrogen receptor and p53 expression (P=0.038, P=0.04, respectively). However, no association was observed between CTGF, estrogen receptor, and p53 expression levels in IOCs. Regarding prognosis, Cyr61 was found to be of no value, but the loss of CTGF was found to be associated with a poor prognosis in multivariate analysis of overall (relative risk 2.8; P=0.050) and disease-free (relative risk 2.3; P=0.031) survival. Cyr61 and CTGF are inversely expressed in BOTs and IOCs, and loss of CTGF independently indicates poor prognosis in IOCs.

The RNA-binding protein Musashi1 affects medulloblastoma growth via a network of cancer-related genes and is an indicator of poor prognosis

Musashi1 (Msi1) is a highly conserved RNA-binding protein that is required during the development of the nervous system. Msi1 has been characterized as a stem cell marker, controlling the balance between self-renewal and differentiation, and has also been implicated in tumorigenesis, being highly expressed in multiple tumor types. We analyzed Msi1 expression in a large cohort of medulloblastoma samples and found that Msi1 is highly expressed in tumor tissue compared with normal cerebellum. Notably, high Msi1 expression levels proved to be a sign of poor prognosis. Msi1 expression was determined to be particularly high in molecular subgroups 3 and 4 of medulloblastoma. We determined that Msi1 is required for tumorigenesis because inhibition of Msi1 expression by small-interfering RNAs reduced the growth of Daoy medulloblastoma cells in xenografts. To characterize the participation of Msi1 in medulloblastoma, we conducted different high-throughput analyses. Ribonucleoprotein immunoprecipitation followed by microarray analysis (RIP-chip) was used to identify mRNA species preferentially associated with Msi1 protein in Daoy cells. We also used cluster analysis to identify genes with similar or opposite expression patterns to Msi1 in our medulloblastoma cohort. A network study identified RAC1, CTGF, SDCBP, SRC, PRL, and SHC1 as major nodes of an Msi1-associated network. Our results suggest that Msi1 functions as a regulator of multiple processes in medulloblastoma formation and could become an important therapeutic target.

CTGF drives autophagy, glycolysis and senescence in cancer-associated fibroblasts via HIF1 activation, metabolically promoting tumor growth

Previous studies have demonstrated that loss of caveolin-1 (Cav-1) in stromal cells drives the activation of the TGF-β signaling, with increased transcription of TGF-β target genes, such as connective tissue growth factor (CTGF). In addition, loss of stromal Cav-1 results in the metabolic reprogramming of cancer-associated fibroblasts, with the induction of autophagy and glycolysis. However, it remains unknown if activation of the TGF-β / CTGF pathway regulates the metabolism of cancer-associated fibroblasts. Therefore, we investigated whether CTGF modulates metabolism in the tumor microenvironment. For this purpose, CTGF was overexpressed in normal human fibroblasts or MDA-MB-231 breast cancer cells. Overexpression of CTGF induces HIF-1α-dependent metabolic alterations, with the induction of autophagy/mitophagy, senescence, and glycolysis. Here, we show that CTGF exerts compartment-specific effects on tumorigenesis, depending on the cell-type. In a xenograft model, CTGF overexpressing fibroblasts promote the growth of co-injected MDA-MB-231 cells, without any increases in angiogenesis. Conversely, CTGF overexpression in MDA-MB-231 cells dramatically inhibits tumor growth in mice. Intriguingly, increased extracellular matrix deposition was seen in tumors with either fibroblast or MDA-MB-231 overexpression of CTGF. Thus, the effects of CTGF expression on tumor formation are independent of its extracellular matrix function, but rather depend on its ability to activate catabolic metabolism. As such, CTGF-mediated induction of autophagy in fibroblasts supports tumor growth via the generation of recycled nutrients, whereas CTGF-mediated autophagy in breast cancer cells suppresses tumor growth, via tumor cell self-digestion. Our studies shed new light on the compartment-specific role of CTGF in mammary tumorigenesis, and provide novel insights into the mechanism(s) generating a lethal tumor microenvironment in patients lacking stromal Cav-1. As loss of Cav-1 is a stromal marker of poor clinical outcome in women with primary breast cancer, dissecting the downstream signaling effects of Cav-1 are important for understanding disease pathogenesis, and identifying novel therapeutic targets.

Connective tissue growth factor expression in precancerous lesions of human esophageal epithelium and prognostic significance in esophageal squamous cell carcinoma

Connective tissue growth factor (CTGF, CCN2), a secreted protein, is involved in the development and progression of esophageal squamous cell carcinoma (ESCC). However, it remains unclear how CTGF expression affects the progression of ESCC. Our study implicated differences of CTGF protein status in precancerous lesions, and retrospectively examined the associations of CTGF mRNA and protein levels with clinical prognosis in ESCC patients. Here immunohistochemistry and the quantitative real-time real-time reverse transcription polymerase were performed for predicting the CTGF protein status and mRNA levels in ESCC patients, respectively. Different degrees of CTGF protein status presented in normal human esophageal epithelium and precancerous lesions, and CTGF protein was highly expressed in ESCCs. Survival analysis showed that CTGF protein status was significantly related to poor survival of ESCC patients (P= 0.024), while no significant difference was observed between CTGF mRNA levels and the survival of ESCC patients (P= 0.196). Multivariate Cox analysis demonstrated that CTGF protein status was the independent factor in prognosis of ESCC patients. In that way, CTGF protein status might elevate the progression of ESCC, and would be significant for the diagnosis of precancerous lesions or early ESCC.

Two different docetaxel resistant MCF-7 sublines exhibited different gene expression pattern

The objective of the present study was to investigate gene expression pattern of two docetaxel resistant MCF-7 breast carcinoma sublines step wisely selected in 30 and 120 nM docetaxel. Cell proliferation assay was performed in order to demonstrate development of docetaxel resistance. cDNA microarray analysis was performed using Affymetrix(®) Human Genome U133 Plus 2.0 Arrays in duplicate experiments. Quantitative and semi-quantitative gene expression analysis was also performed to confirm gene expression analysis for selected genes. XTT results demonstrated that 30 (MCF-7/30nM DOC) and 120 nM (MCF-7/120nM DOC) docetaxel selected cells were 13- and 47-fold resistant, respectively. cDNA microarray analysis demonstrated that expression profiles of MCF-7 and MCF-7/30nM DOC were more similar to each other where expression profile of MCF-7/120nM DOC was different as examined by line graphs and scatter plots. 2,837 and 4,036 genes were significantly altered in 30 and 120 nM docetaxel resistant sublines, respectively. Among these, 849 genes were altered in common in two docetaxel resistant sublines. Antiapoptotic gene expression (e.g., Bcl-2 and APRIL) were noticeably altered in MCF-7/30nM DOC. However, docetaxel resistance in MCF-7/120nM DOC were more complicated with the involvement of ECM related gene expression, cytokine and growth factor signaling, ROS metabolism and EMT related gene expression together with higher level of MDR1 expression. Expression profiles in 30 and 120 nM docetaxel resistant sublines changed gradually with increasing resistance index. Drug resistance development seems to be step wise event in MCF-7 cells.

CTGF is overexpressed in malignant melanoma and promotes cell invasion and migration

BACKGROUND

Malignant melanoma cells are known to have altered expression of growth factors compared with normal human melanocytes. These changes most likely favour tumour growth and progression, and influence tumour environment. The induction of transforming growth factor beta1, 2 and 3 as well as BMP4 and BMP7 expression in malignant melanoma has been reported before, whereas the expression of an important modulator of these molecules, connective tissue growth factor (CTGF), has not been investigated in melanomas until now.

METHODS

Expression of CTGF was analysed in melanoma cell lines and tissue samples by qRT-PCR and immunohistochemistry. To determine the regulation of CTGF expression in malignant melanoma, specific siRNA was used. Additionally, migration, invasion and attachment assays were carried out.

RESULTS

We were able to demonstrate that CTGF expression is upregulated in nine melanoma cell lines and in primary and metastatic melanoma in situ. The transcription factor HIF-1α was revealed as a positive regulator for CTGF expression. Melanoma cells, in which CTGF expression is diminished, show a strong reduction of migratory and invasive properties when compared with controls. Further, treatment of normal human epidermal melanocytes with recombinant CTGF leads to an increase of migratory and invasive behaviour of these cells.

CONCLUSION

These results suggest that CTGF promotes melanoma cell invasion and migration and, therefore, has an important role in the progression of malignant melanoma.

CCN2 expression and localization in melanoma cells

The matricellular protein connective tissue growth factor (CTGF, CCN2) is overexpressed in several forms of cancer and may represent a novel target in anti-cancer therapy. However, whether CCN2 is expressed in melanoma cells is unknown. The highly metastatic murine melanoma cell line B16(F10) was used for our studies. Real time polymerase chain reaction analysis was used to detect mRNA expression of CCN1, CCN2, CCN3 and CCN4 in Western blot and immunofluorescence analyses were used to detect CCN2 protein. Inhibitors of signal transduction cascades were used to probe the mechanism underlying CCN2 expression in B16(F10) cells. CCN2 was expressed in B16(F10) cells, and was reduced by the FAK/src inhibitor PP2 and the MEK/ERK inhibitor U0126 indicating that CCN2 acts downstream of these pathways in B16(F10) murine melanoma cells. Expression of CCN1, CCN3 and CCN4 was not reduced by PP2 or U0126; in fact, expression of CCN4 mRNA was elevated by PP2 or U0126 treatment. To our surprise, CCN2 protein was detected in the nuclei of B16(F10) cells, and was undetectable in the cytoplasm. CCN2 was expressed in B16(F10) melanoma cells, adding to the list of cancer cells in which CCN2 is expressed. Of the CCN family members tested, only CCN2 is downstream of the highly oncogenic MEK/ERK pathway. CCN2 should be further evaluated for a possible role in melanoma growth and progression.

Hypoxia, inflammation, and the tumor microenvironment in metastatic disease

Metastasis, the leading cause of cancer deaths, is an intricate process involving many important tumor and stromal proteins that have yet to be fully defined. This review discusses critical components necessary for the metastatic cascade, including hypoxia, inflammation, and the tumor microenvironment. More specifically, this review focuses on tumor cell and stroma interactions, which allow cell detachment from a primary tumor, intravasation to the blood stream, and extravasation at a distant site where cells can seed and tumor metastases can form. Central players involved in this process and discussed in this review include integrins, matrix metalloproteinases, and soluble growth factors/matrix proteins, including the connective tissue growth factor and lysyl oxidase.

LC3-mediated fibronectin mRNA translation induces fibrosarcoma growth by increasing connective tissue growth factor

Previously, we related fibronectin (Fn1) mRNA translation to an interaction between an AU-rich element in the Fn1 3' UTR and light chain 3 (LC3) of microtubule-associated proteins 1A and 1B. Since human fibrosarcoma (HT1080) cells produce little fibronectin and LC3, we used these cells to investigate how LC3-mediated Fn1 mRNA translation might alter tumor growth. Transfection of HT1080 cells with LC3 enhanced fibronectin mRNA translation. Using polysome analysis and RNA-binding assays, we show that elevated levels of translation depend on an interaction between a triple arginine motif in LC3 and the AU-rich element in Fn1 mRNA. Wild-type but not mutant LC3 accelerated HT1080 cell growth in culture and when implanted in SCID mice. Comparison of WT LC3 with vector-transfected HT1080 cells revealed increased fibronectin-dependent proliferation, adhesion and invasion. Microarray analysis of genes differentially expressed in WT and vector-transfected control cells indicated enhanced expression of connective tissue growth factor (CTGF). Using siRNA, we show that enhanced expression of CTGF is fibronectin dependent and that LC3-mediated adhesion, invasion and proliferation are CTGF dependent. Expression profiling of soft tissue tumors revealed increased expression of both LC3 and CTGF in some locally invasive tumor types.

Connective tissue growth factor confers drug resistance in breast cancer through concomitant up-regulation of Bcl-xL and cIAP1

Connective tissue growth factor (CTGF) expression is elevated in advanced breast cancer and promotes metastasis. Chemotherapy response is only transient in most metastatic diseases. In the present study, we examined whether CTGF expression could confer drug resistance in human breast cancer. In breast cancer patients who received neoadjuvant chemotherapy, CTGF expression was inversely associated with chemotherapy response. Overexpression of CTGF in MCF7 cells (MCF7/CTGF) enhanced clonogenic ability, cell viability, and resistance to apoptosis on exposure to doxorubicin and paclitaxel. Reducing the CTGF level in MDA-MB-231 (MDA231) cells by antisense CTGF cDNA (MDA231/AS cells) mitigated this drug resistance capacity. CTGF overexpression resulted in resistance to doxorubicin- and paclitaxel-induced apoptosis by up-regulation of Bcl-xL and cellular inhibitor of apoptosis protein 1 (cIAP1). Knockdown of Bcl-xL or cIAP1 with specific small interfering RNAs abolished the CTGF-mediated resistance to apoptosis induced by the chemotherapeutic agents in MCF7/CTGF cells. Inhibition of extracellular signal-regulated kinase (ERK)-1/2 effectively reversed the resistance to apoptosis as well as the up-regulation of Bcl-xL and cIAP1 in MCF7/CTGF cells. A neutralizing antibody against integrin alpha(v)beta(3) significantly attenuated CTGF-mediated ERK1/2 activation and up-regulation of Bcl-xL and cIAP1, indicating that the integrin alpha(v)beta(3)/ERK1/2 signaling pathway is essential for CTGF functions. The Bcl-xL level also correlated with the CTGF level in breast cancer patients. We also found that a COOH-terminal domain peptide from CTGF could exert activities similar to full-length CTGF, in activation of ERK1/2, up-regulation of Bcl-xL/cIAP1, and resistance to apoptosis. We conclude that CTGF expression could confer resistance to chemotherapeutic agents through augmenting a survival pathway through ERK1/2-dependent Bcl-xL/cIAP1 up-regulation.

Induction of antiproliferative connective tissue growth factor expression in Wilms' tumor cells by sphingosine-1-phosphate receptor 2

Connective tissue growth factor (CTGF), a member of the CCN family of secreted matricellular proteins, regulates fibrosis, angiogenesis, cell proliferation, apoptosis, tumor growth, and metastasis. However, the role of CTGF and its regulation mechanism in Wilms' tumor remains largely unknown. We found that the bioactive lipid sphingosine-1-phosphate (S1P) induced CTGF expression in a concentration- and time-dependent manner in a Wilms' tumor cell line (WiT49), whereas FTY720-phosphate, an S1P analogue that binds all S1P receptors except S1P2, did not. Further, the specific S1P2 antagonist JTE-013 completely inhibited S1P-induced CTGF expression, whereas the S1P1 antagonist VPC44116 did not, indicating that this effect was mediated by S1P2. This was confirmed by adenoviral transduction of S1P2 in WiT49 cells, which showed that overexpression of S1P2 increased the expression of CTGF. Induction of CTGF by S1P was sensitive to ROCK inhibitor Y-27632 and c-Jun NH2-terminal kinase inhibitor SP600125, suggesting the requirement of RhoA/ROCK and c-Jun NH2-terminal kinase pathways for S1P-induced CTGF expression. Interestingly, the expression levels of CTGF were decreased in 8 of 10 Wilms' tumor tissues compared with matched normal tissues by quantitative real-time PCR and Western blot analysis. In vitro, human recombinant CTGF significantly inhibited the proliferation of WiT49 cells. In addition, overexpression of CTGF resulted in significant inhibition of WiT49 cell growth. Taken together, these data suggest that CTGF protein induced by S1P2 might act as a growth inhibitor in Wilms' tumor.

Serial analysis of gene expression identifies connective tissue growth factor expression as a prognostic biomarker in gallbladder cancer

BACKGROUND

Gallbladder cancer (GBC) is an uncommon neoplasm in the United States, but one with high mortality rates. This malignancy remains largely understudied at the molecular level such that few targeted therapies or predictive biomarkers exist.

EXPERIMENTAL DESIGN

We built the first series of serial analysis of gene expression (SAGE) libraries from GBC and nonneoplastic gallbladder mucosa, composed of 21-bp long-SAGE tags. SAGE libraries were generated from three stage-matched GBC patients (representing Hispanic/Latino, Native American, and Caucasian ethnicities, respectively) and one histologically alithiasic gallbladder. Real-time quantitative PCR was done on microdissected epithelium from five matched GBC and corresponding nonneoplastic gallbladder mucosa. Immunohistochemical analysis was done on a panel of 182 archival GBC in high-throughput tissue microarray format.

RESULTS

SAGE tags corresponding to connective tissue growth factor (CTGF) transcripts were identified as differentially overexpressed in all pairwise comparisons of GBC (P < 0.001). Real-time quantitative PCR confirmed significant overexpression of CTGF transcripts in microdissected primary GBC (P < 0.05), but not in metastatic GBC, compared with nonneoplastic gallbladder epithelium. By immunohistochemistry, 66 of 182 (36%) GBC had high CTGF antigen labeling, which was significantly associated with better survival on univariate analysis (P = 0.0069, log-rank test).

CONCLUSIONS

An unbiased analysis of the GBC transcriptome by SAGE has identified CTGF expression as a predictive biomarker of favorable prognosis in this malignancy. The SAGE libraries from GBC and nonneoplastic gallbladder mucosa are publicly available at the Cancer Genome Anatomy Project web site and should facilitate much needed research into this lethal neoplasm.

Connective tissue growth factor (CTGF) and cancer progression

Connective tissue growth factor (CTGF) is a member of the CCN family of secreted, matrix-associated proteins encoded by immediate early genes that play various roles in angiogenesis and tumor growth. CCN family proteins share uniform modular structure which mediates various cellular functions such as regulation of cell division, chemotaxis, apoptosis, adhesion, motility, angiogenesis, neoplastic transformation, and ion transport. Recently, CTGF expression has been shown to be associated with tumor development and progression. There is growing body of evidence that CTGF may regulate cancer cell migration, invasion, angiogenesis, and anoikis. In this review, we will highlight the influence of CTGF expression on the biological behavior and progression of various cancer cells, as well as its regulation on various types of protein signals and their mechanisms.

Molecular requirements for induction of CTGF expression by TGF-beta1 in primary osteoblasts

Connective tissue growth factor (CTGF/CCN2) is a cysteine rich, extracellular matrix protein that acts as an anabolic growth factor to regulate osteoblast differentiation and function. In osteoblasts, CTGF is induced by TGF-beta1 where it acts as a downstream mediator of TGF-beta1 induced matrix production. The molecular mechanisms that control CTGF induction by TGF-beta1 in osteoblasts are not known. To assess the role of individual Smads in mediating the induction of CTGF by TGF-beta1, we used specific Smad siRNAs to block Smad expression. These studies demonstrated that Smads 3 and 4, but not Smad 2, are required for TGF-beta1 induced CTGF promoter activity and expression in osteoblasts. Since the activation of MAPKs (Erk, Jnk and p38) by TGF-beta1 is cell type specific, we were interested in determining the role of individual MAPKs in TGF-beta1 induction of CTGF promoter activity and expression. Using dominant negative (DN) mutants for Erk, Jnk and p38, we demonstrated that the expression of DN-Erk caused a significant inhibition of TGF-beta1 induced CTGF promoter activity. In contrast, the expression of DN-p38 or DN-Jnk failed to inhibit activation of CTGF promoter activity. To confirm the vital role of Erk, we used the Erk inhibitor (PD98059) to block its activation, demonstrating that it prevented TGF-beta1 activation of the CTGF promoter and up-regulation of CTGF expression in osteoblasts. Since Src can also act as a downstream signaling effector for TGF-beta in some cell types, we determined its role in TGF-beta1 induction of CTGF in osteoblasts. Treatment of osteoblasts with a Src family kinase inhibitor, PP2, or the expression of two independent kinase-dead Src mutant constructs caused significant inhibition of TGF-beta1 induced CTGF promoter activity and expression. Additionally, blocking Src activation prevented Erk activation by TGF-beta1 demonstrating a role for Src as an upstream mediator of Erk in regulating CTGF expression in osteoblasts. To investigate the involvement of the TGF-beta1 response element (TRE) and the SMAD binding element (SBE) in CTGF induction, we cloned the rat CTGF proximal promoter (-787 to +1) containing the TRE and SBE motifs into a pGL3-Luciferase reporter construct. Using a combination of CTGF promoter deletion constructs and site-directed mutants, we demonstrated the unique requirement of both the TRE and SBE for CTGF induction by TGF-beta1 in osteoblasts. Electro-mobility shift assays using specific probes containing the TRE, SBE or both showed TGF-beta1 inducible complexes that can be ablated by mutation of the respective motif, confirming their requirement for TGF-beta1 induced CTGF promoter activity. In conclusion, these studies demonstrate that CTGF induction by TGF-beta1 in osteoblasts involves Smads 3 and 4, the Erk and Src signaling pathways, and requires both the TRE and SBE motifs in the CTGF proximal promoter.

Expression of connective tissue growth factor in tumor tissues is an independent predictor of poor prognosis in patients with gastric cancer

AIM: To examine the expression of connective tissue growth factor (CTGF), also known as CCN2, in gastric carcinoma (GC), and the correlation between the expression of CTGF, clinicopathologic features and clinical outcomes of patients with GC.

METHODS: One hundred and twenty-two GC patients were included in the present study. All patients were followed up for at least 5 years. Proteins of CTGF were detected using the Powervision two-step immunostaining method.

RESULTS: Of the specimens from 122 GC patients analyzed for CTGF expression, 58 (58/122, 47.5%) had a high CTGF expression in cytoplasm of gastric carcinoma cells and 64 (64/122, 52.5%) had a low CTGF expression. Patients with a high CTGF expression showed a higher incidence of lymph node metastasis than those with a low CTGF expression (P = 0.032). Patients with a high CTGF expression had significantly lower 5-year survival rate than those with a low CTGF expression (27.6% vs 46.9%, P = 0.0178), especially those staging I + II + III (35.7% vs 65.2%, P = 0.0027).

CONCLUSION: GC patients with an elevated CTGF expression have more lymph node metastases and a shorter survival time. CTGF seems to be an independent prognostic factor for the successful differentiation of high-risk GC patients staging I + II + III. Over-expression of CTGF in human GC cells results in an increased aggressive ability.

Expression of connective tissue growth factor is in agreement with the expression of VEGF, VEGF-C, -D and associated with shorter survival in gastric cancer

Connective tissue growth factor (CTGF) is believed to be a multifunctional signaling modulator involved in a wide variety of biological or pathological processes including carcinogenesis. The role of CTGF in gastric cancer (GC) has not been reported so far. In the present study the expression of CTGF, vascular endothelial growth factor (VEGF), VEGF-C and VEGF-D on immunohistochemistry in GC and the correlation between the expression of CTGF and VEGF, VEGF-C, VEGF-D were examined, along with the correlation between the expression of CTGF and clinicopathological parameters, as well as survival of the patients with GC. The expression of CTGF was significantly in agreement with expression of VEGF, VEGF-C and VEGF-D (kappa and P, respectively: 0.538, P < 0.001; 0.502, P < 0.001; 0.558, P < 0.001). High CTGF expression was significantly associated with lymph nodes metastasis (P = 0.038) and lower postoperative 5 year overall survival rates (23.9%) compared with those patients with low CTGF expression (48.4%, P = 0.0035). The present findings suggest that CTGF is a useful prognostic marker for GC. High CTGF expression is associated with the risk of lymph nodes metastasis and a poor survival time in GC.

Connective tissue growth factor is an indicator of bone involvement in multiple myeloma, but matrix metalloproteinase-9 is not

Bone disease (BD) in multiple myeloma (MM) is because of the activation of osteoclasts and impairment of osteoblast differentiation. Connective tissue growth factor (CTGF) is known to participate in the differentiation of mesenchymal stem cells to committed osteoprogenitor cells. We analysed the concentration of circulating CTGF in 35 MM patients and 22 malignant lymphoma (ML) patients and 14 normal individuals. CTGF is protease-sensitive and thus is found as both an N-terminal half fragment (N-half CTGF) and whole (W-CTGF). Serum levels of W-CTGF and N-half CTGF + W-CTGF were determined by separate sandwich enzyme-linked immunosorbent assays. The level of W-CTGF was significantly lower (P < 0.005) in MM patients compared with ML patients and normal individuals, while N-half + W-CTGF was similar in all groups. Furthermore, W-CTGF was significantly lower in MM patients with BD compared with those without BD (P < 0.005) and this was independent of previous treatment. Matrix metalloproteinase (MMP)-9 is produced by myeloma cells and is thought to be related to BD in MM. However, MMP-9 does not cleave CTGF and serum MMP-9 level was not related to BD in MM. Thus, CTGF is an indicator of BD in MM; its metabolism and function in MM should be clarified.

Promoter hypermethylation contributes to frequent inactivation of a putative conditional tumor suppressor gene connective tissue growth factor in ovarian cancer

Connective tissue growth factor (CTGF) is a secreted protein belonging to the CCN family, members of which are implicated in various biological processes. We identified a homozygous loss of CTGF (6q23.2) in the course of screening a panel of ovarian cancer cell lines for genomic copy number aberrations using in-house array-based comparative genomic hybridization. CTGF mRNA expression was observed in normal ovarian tissue and immortalized ovarian epithelial cells but was reduced in many ovarian cancer cell lines without its homozygous deletion (12 of 23 lines) and restored after treatment with 5-aza 2'-deoxycytidine. The methylation status around the CTGF CpG island correlated inversely with the expression, and a putative target region for methylation showed promoter activity. CTGF methylation was frequently observed in primary ovarian cancer tissues (39 of 66, 59%) and inversely correlated with CTGF mRNA expression. In an immunohistochemical analysis of primary ovarian cancers, CTGF protein expression was frequently reduced (84 of 103 cases, 82%). Ovarian cancer tended to lack CTGF expression more frequently in the earlier stages (stages I and II) than the advanced stages (stages III and IV). CTGF protein was also differentially expressed among histologic subtypes. Exogenous restoration of CTGF expression or treatment with recombinant CTGF inhibited the growth of ovarian cancer cells lacking its expression, whereas knockdown of endogenous CTGF accelerated growth of ovarian cancer cells with expression of this gene. These results suggest that epigenetic silencing by hypermethylation of the CTGF promoter leads to a loss of CTGF function, which may be a factor in the carcinogenesis of ovarian cancer in a stage-dependent and/or histologic subtype-dependent manner.

Expression of Cyr61, CTGF, and WISP-1 correlates with clinical features of lung cancer

Background

CCN family, comprising six members (Cyr61, CTGF, Nov, WISP-1, WISP-2, WISP-3), is involved in the stimulation of cell proliferation, migration, adhesion, angiogenesis, and tumorigenesis. Several studies have shown that expression of Cyr61, CTGF, and WISP-1 affects the tumorigenic potential of lung cancer cells in vitro. However, the correlation of expression of CCN family proteins and clinical features of lung cancer remains unknown.

Methodology and Principal Findings

In the present work, we quantified the mRNA levels of Cyr61, CTGF, and WISP-1 in samples from 60 primary lung cancers and their matched normal lung tissues by quantitative real-time PCR assay. Downregulation of the Cyr61 and CTGF genes and upregulation of the WISP-1 gene were found in primary lung cancers compared to the paired normal lung tissues. Immunohistochemistry analysis also disclosed a similar expression pattern of Cyr61, CTGF, and WISP-1 protein in paired lung cancer tissues. Statistical analysis revealed significant associations between expression of either Cyr61 or CTGF with tumor stage, tumor histology, metastasis, smoking, and family history at diagnosis. A significant correlation also existed between WISP-1 expression with tumor histology, and patient age. Moreover, expression levels of Cyr61 and CTGF correlated with survival of the lung-cancer patients.

Conclusions

Our results suggest that Cyr61, CTGF, and WISP-1 might be implicated in the development and progression of primary lung cancers, and their levels might serve as valuable prognostic markers, as well as potential targets for therapeutic intervention.

Connective tissue growth factor (CTGF/CCN2) is a downstream mediator for TGF-beta1-induced extracellular matrix production in osteoblasts

Connective tissue growth factor (CTGF/CCN2) is a cysteine-rich, extracellular matrix (ECM) protein that acts as an anabolic growth factor to regulate osteoblast differentiation and function. Recent studies have identified CTGF as a downstream effector of transforming growth factor-beta1 (TGF-beta1) for certain functions in specific cell types. In this study, we examined the role of CTGF as a downstream mediator of TGF-beta1-induced ECM production and cell growth in osteoblasts. Using primary cultures, we demonstrated that TGF-beta1 is a potent inducer of CTGF expression in osteoblasts, and that this induction occurred at all stages of osteoblast differentiation from the proliferative through mineralization stages. TGF-beta1 treatment of osteoblasts increased the expression and synthesis of the ECM components, collagen and fibronectin. When CTGF-specific siRNA was used to prevent TGF-beta1 induction of CTGF expression, it also inhibited collagen and fibronectin production, thereby demonstrating the requirement of CTGF for their up-regulation. To examine the effects of TGF-beta1 on osteoblast cell growth, cultures were treated with TGF-beta1 during the proliferative stage. Cell number was significantly reduced and the cells exhibited a decrease in G1 cyclin expression, consistent with TGF-beta1-induced cell-cycle arrest. Cultures transfected with CTGF siRNA prior to TGF-beta1 treatment showed an even greater reduction in cell number, suggesting that TGF-beta1-induced growth arrest is independent of CTGF in osteoblasts. Collectively, these data demonstrate for the first time that CTGF is an essential downstream mediator for TGF-beta1-induced ECM production in osteoblasts, but these two growth factors function independently regarding their opposing effects on osteoblast proliferation.

Role of CCN2/CTGF/Hcs24 in bone growth

Our bones mostly develop through a process called endochondral ossification. This process is initiated in the cartilage prototype of each bone and continues through embryonic and postnatal development until the end of skeletal growth. Therefore, the central regulator of endochondral ossification is the director of body construction, which is, in other words, the determinant of skeletal size and shape. We suggest that CCN2/CTGF/Hcs24 (CCN2) is a molecule that conducts all of the procedures of endochondral ossification. CCN2, a member of the CCN family of novel modulator proteins, displays multiple functions by manipulating the local information network, using its conserved modules as an interface with a variety of other biomolecules. Under a precisely designed four-dimensional genetic program, CCN2 is produced from a limited population of chondrocytes and acts on all of the mesenchymal cells inside the bone callus to promote the integrated growth of the bone. Furthermore, the utility of CCN2 as regenerative therapeutics against connective tissue disorders, such as bone and cartilage defects and osteoarthritis, has been suggested. Over the years, the pathological action of CCN2 has been suggested. Nevertheless, it can also be regarded as another aspect of the physiological and regenerative function of CCN2, which is discussed as well.

Role of CCN2/CTGF in the proliferation of Mastomys enterochromaffin-like cells and gastric carcinoid development

Mastomys enterochromaffin-like (ECL) cell proliferation is initially gastrin driven, but once neoplasia develops, cells become gastrin autonomous. We hypothesized that CCN2 (CTGF), a mitogenic growth factor, may regulate ECL cell proliferation. A Mastomys GeneChip database was examined (dCHIP) to identify CCN2 expression levels. CCN2 in normal and tumor ECL cell preparations obtained using FACS (100 nM acridine orange) was examined by real-time PCR. CCN2 protein was identified in mucosal and ECL cell preparations by immunohistochemistry. Short-term cultured cells were stimulated with either CCN2 or CCN2 + EGF, and proliferation was measured (MTT assay). The ERK1/2 inhibitor PD-98059 (0.1-100 microM) was assessed in terms of CCN2 (1 ng/ml)-mediated proliferation and ERK1/2 phosphorylation. CCN2 transcript and protein was then examined in clinical gastric carcinoids. The ccn2 transcript was upregulated in tumor samples compared with the normal mucosa (+2.36-fold, P < 0.01). PCR demonstrated that ccn2 was not expressed in FACS-prepared (>98% pure) normal ECL cells but was elevated in tumor ECL cell fractions (41.3 +/- 10.7-fold). Immunostaining of the Mastomys gastric mucosa and FACS preparations confirmed that CCN2 protein was present in ECL tumors but not in normal ECL cells. Neither CCN2 nor CCN2 + EGF stimulated normal ECL cell proliferation. CCN2 stimulated tumor proliferation (EC50 approximately 0.01 ng/ml); EGF significantly augmented (P < 0.01) CCN2-induced tumor cell proliferation (EC50 = 20 pg/ml). PD-98059 inhibited CCN2-induced proliferation (-12 +/- 3%, P < 0.05) and ERK1/2 phosphorylation (-34 +/- 5%, P < 0.05) in tumor cells. In clinical samples, both CCN2 transcript and protein were elevated in gastrin-autonomous carcinoids (P < 0.02) compared with the normal mucosa. In conclusion, CCN2 may be a proliferative regulator of Mastomys ECL neoplastic proliferation once these cells become autonomous of gastrin regulation. Identification of CCN2 in gastric carcinoid tissue may be useful both as an indicator of ECL cell transformation and may define gastrin autonomy, a criteria of gastric carcinoid malignancy.

CCN family proteins and angiogenesis: from embryo to adulthood

The CCN family is a novel class of extracellular signal modulators that has been recently established. Typical members are composed of four conserved modules connected tandem, each of which is rich in cysteines and highly interactive with other molecules. The mammalian CCN family consists of six members, most of which have been described as multifunctional factors for the developmental process of mesenchymal tissue including blood vessel formation/induction. Particularly, the angiogenic properties of the three classical members, CCN1, 2 and 3 have so far been characterized, and their physiological and pathological significance has thus been indicated. Recent research has uncovered a unique mechanism regarding these proteins in promoting and/or modulating developmental, physiological and pathological angiogenic events. Namely, CCN proteins exert their ability to drive angiogenesis, not by stimulating a particular behavior of a particular type of cells, but by manipulating the cell communication networks that integrate most of the associated molecules/cells toward angiogenesis. In this article, the role of the CCN proteins in a variety of angiogenic events as an organizer of microenvironmental cell society is comprehensively described, together with a brief summary of the recent findings on each CCN family member relevant to angiogenesis including cardiovascular development and diseases.

Connective Tissue Growth Factor–Specific Monoclonal Antibody Therapy Inhibits Pancreatic Tumor Growth and Metastasis

Pancreatic cancer is highly aggressive and refractory to most existing therapies. Past studies have shown that connective tissue growth factor (CTGF) expression is elevated in human pancreatic adenocarcinomas and some pancreatic cancer cell lines. To address whether and how CTGF influences tumor growth, we generated pancreatic tumor cell lines that overexpress different levels of human CTGF. The effect of CTGF overexpression on cell proliferation was measured in vitro in monolayer culture, suspension culture, or soft agar, and in vivo in tumor xenografts. Although there was no effect of CTGF expression on proliferation in two-dimensional cultures, anchorage-independent growth (AIG) was enhanced. The capacity of CTGF to enhance AIG in vitro was linked to enhanced pancreatic tumor growth in vivo when these cells were implanted s.c. in nude mice. Administration of a neutralizing CTGF-specific monoclonal antibody, FG-3019, had no effect on monolayer cell proliferation, but blocked AIG in soft agar. Consistent with this observation, anti-CTGF treatment of mice bearing established CTGF-expressing tumors abrogated CTGF-dependent tumor growth and inhibited lymph node metastases without any toxicity observed in normal tissue. Together, these studies implicate CTGF as a new target in pancreatic cancer and suggest that inhibition of CTGF with a human monoclonal antibody may control primary and metastatic tumor growth.

Connective tissue growth factor–specific antibody attenuates tumor growth, metastasis, and angiogenesis in an orthotopic mouse model of pancreatic cancer

Connective tissue growth factor (CTGF) plays an important role in fibrosis by modulating cell migration and cell growth but may also modify tumor growth and metastasis. Because CTGF is overexpressed in pancreatic ductal adenocarcinoma, we investigated the in vitro effects of CTGF on the proliferation and invasiveness of PANC-1 pancreatic cancer cells and examined the consequences of its in vivo inhibition on the growth and metastasis of these cells using a fully human CTGF-specific monoclonal antibody (FG-3019) in an orthotopic nude mouse model. Although PANC-1 cells expressed relatively high levels of endogenous CTGF mRNA, the addition of CTGF to conditioned medium increased the proliferation and invasiveness of PANC-1 cells. Moreover, transforming growth factor-beta1 caused a further increase in CTGF expression in these cells. In vivo, the twice weekly i.p. administration of FG-3019 decreased tumor growth and metastasis and attenuated tumor angiogenesis and cancer cell proliferation. FG-3019 did not enhance apoptosis and did not attenuate the inhibitory effects of gemcitabine on tumor growth and metastasis. These findings suggest that CTGF may contribute to aberrant autocrine and paracrine pathways that promote pancreatic cancer cell growth, invasion, metastasis, and angiogenesis. Therefore, blocking CTGF actions with FG-3019 may represent a novel therapeutic approach in pancreatic ductal adenocarcinoma.

Translational repression by thecis-acting element of structure-anchored repression (CAESAR) of humanctgf/ccn2mRNA

The cis-acting element of structure-anchored repression (CAESAR) is a post-transcriptional regulatory element of gene expression, which is located in the 3'-untranslated region (UTR) of the human ccn2 gene (ctgf/ccn2). In this report, the repression mechanism of CAESAR, as well as the structural requirement, was investigated. Removal of minor stem-loops from CAESAR resulted in proportional attenuation of the repressive function, whereas removal of the single bulge or modification of primary nucleotide sequence did not affect its functionality. In light of functional mechanism, CAESAR exerted no significant effects on stability or nuclear export of the cis-linked mRNA. However, this element significantly interfered with the association of such mRNA on ribosome and slowed down the translation process thereafter in vitro. A translation repression mechanism by RNA secondary structure to determine the basal ctgf/ccn2 expression level was uncovered herein.

High invasive melanoma cells induce matrix metalloproteinase-1 synthesis in fibroblasts by interleukin-1alpha and basic fibroblast growth factor-mediated mechanisms

Tumor invasion and metastasis of melanoma have been shown to require proteolytic degradation of the extracellular environment, achieved primarily by enzymes of the matrix metalloproteinases (MMP) family. Increased enzyme activity is localized at the border of tumor cells and the adjacent peritumoral connective tissue, emphasizing the crucial role of tumor-stroma interactions in the regulation of MMP activity. To analyze whether direct cell-cell contacts of melanoma cells and stromal fibroblasts or whether soluble factors, secreted by melanoma cells are involved in the regulation of MMP, we used different in vitro co-culture systems. Both direct and indirect co-cultures of high invasive BLM melanoma cells and human dermal fibroblasts resulted in an induction of pro-MMP-1 synthesis. Medium conditioned by BLM cells strongly induced pro-MMP-1 synthesis in fibroblasts, indicating the importance of diffusible factors for this induction. Competition by recombinant human interleukin (IL)-1 receptor antagonist, neutralizing IL-1alpha and basic fibroblast growth factor (bFGF) antibodies, resulted in a concentration-dependent reduction of pro-MMP-1 synthesis. Taken together, our results indicate an essential role for soluble factors, mainly IL-1alpha and bFGF, in the stimulation of dermal fibroblasts by human melanoma cells to secrete MMP-1.

Spinal cord injury induction of lesional expression of profibrotic and angiogenic connective tissue growth factor confined to reactive astrocytes, invading fibroblasts and endothelial cells

OBJECT

The glial scar composed of astrogliosis and extracellular matrix deposition represents a major impediment to axonal regeneration. The authors investigated the role of a novel profibrotic and angiogenic peptide connective tissue growth factor (CTGF [Hcs24/IGFBP-r2P]) in glial scar formation following spinal cord injury (SCI) in rats.

METHODS

The effects of SCI on CTGF expression during glial scar maturation 1 day to 1 month post-SCI were investigated using fluorescein-activated cell sorter (FACS) immunohistochemical analysis; these findings were compared with those obtained in sham-operated (control) spinal cords. The CTGF-positive cells accumulated at the spinal cord lesion site (p < 0.0001) corresponding to areas of glial scar formation. In the perilesional rim, CTGF expression was confined to invading vimentin-positive, glial fibrillary acidic protein (GFAP)-negative fibroblastoid cells, endothelial and smooth-muscle cells of laminin-positive vessels, and GFAP-positive reactive astrocytes. The CTGF-positive astrocytes coexpressed the activation-associated intermediate filaments nestin, vimentin (> 80%), and mesenchymal scar component fibronectin (50%).

CONCLUSIONS

The restricted accumulation of CTGF-reactive astrocytes and CTGF-positive fibroblastoid cells lining the laminin-positive basal neolamina suggests participation of these cells in scar formation. In addition, perilesional upregulation of endothelial and smooth-muscle CTGF expression points to a role in blood-brain barrier function modulating edema-induced secondary damage.

Distinction of desmoplastic melanoma from non-desmoplastic melanoma by gene expression profiling

Desmoplastic melanoma (DM) is a variant of melanoma characterized by the presence of amelanotic fusiform melanocytes dispersed in a prominent collagenous stroma. DM behaves differently from conventional non-desmoplastic melanoma (NDM). It has a higher tendency for local recurrence and is less likely to metastasize to regional lymph nodes. In this study, we explored the possibility of distinguishing DM from NDM by gene expression profiling. RNA samples from ten primary cutaneous melanomas of similar depth of invasion were analyzed using the Affymetrix U133A oligonucleotide platform. Four tumors were DM, five were ND, and one tumor showed combined features of desmoplastic and conventional. Hierarchical cluster analysis clearly separated DM from NDM. The expression of a number of melanocyte differentiation genes was decreased in DM compared with NDM, which corresponded to immunohistochemical results. Various genes were upregulated in DM, including neurotrophic factors and genes involved in extracellular matrix production. A novel finding was the high expression of clusterin in DM, which was confirmed by immunohistochemical studies. Our results from gene expression profiling validate the distinction of DM from NDM. They also provide the opportunity to learn more about the biology of DM which had previously not yet been associated with this variant of melanoma.

Connective tissue growth factor inhibits metastasis and acts as an independent prognostic marker in colorectal cancer

BACKGROUND & AIMS

Connective tissue growth factor (CTGF) has been shown to be implicated in tumor development and progression. The aim of this study was to investigate the role of CTGF in progression of colorectal cancer (CRC).

METHODS

Immunohistochemical staining of specimens from 119 patients with CRC was performed. Liposome-mediated transfection was used to introduce a CTGF expression vector into CRC cell lines. Transfectants were tested in invasive ability and experimental hepatic metastasis in BALB/c mice. Furthermore, a FOPflash/TOPflash reporter assay was performed to investigate CTGF on the beta-catenin/T-cell factor signaling pathway.

RESULTS

Patients with stage II and stage III CRC whose tumors displayed high CTGF expression had a significantly higher overall survival and a disease-free advantage over patients with CRC with low CTGF expression. Alterations in the CTGF level in CRC cell lines modulated their invasive ability with an inverse correlation. In addition, a reduction in the CTGF level of CT26 cells after stable transfection with antisense CTGF resulted in increased liver metastasis in BALB/c mice. The activity of the beta-catenin/T-cell factor signaling pathway and its downstream effector gene matrix metalloproteinase 7 in these CTGF-transfected cells was strongly attenuated. Blockage of matrix metalloproteinase 7 with its neutralizing antibodies inhibited increased invasiveness in antisense CTGF-transfected CT26 cells.

CONCLUSIONS

Our results implicate CTGF as a key regulator of CRC invasion and metastasis, and it appears to be a useful and better prognosis factor for patients with stage II and stage III CRC.

Expressions of cysteine-rich61, connective tissue growth factor and Nov genes in hepatocellular carcinoma and their clinical significance

AIM: To investigate the expression of cysteine-rich61 (Cyr61), connective tissue growth factor (CTGF) and nephroblastoma overexpressed gene (Nov) in hepatocellular carcinoma (HCC), and to evaluate the relationship between Cyr61, CTGF and Nov genes expression with invasion and metastasis of HCC.

METHODS: Thirty-one HCC specimens were divided into small hepatocellular carcinoma (SHCC), nodular hepatocellular carcinoma (NHCC), solitary large hepatocellular carcinoma (SLHCC) according to their diameter and number of nodes. Reverse transcription polymerse chain reaction (RT-PCR) was used to detect the mRNA expression levels of Cyr61, CTGF and Nov genes in 31 resected specimens of hepatocellular carcinoma and para-cancerous normal liver tissues semi-quantitatively and the relation between their expression levels and clinical pathological parameters were compared.

RESULTS: The expressions of Cyr61 and CTGF mRNA in carcinoma tissues were significantly higher than those in para-cancerous normal liver tissues (P < 0.01). The expressions of Cyr61 and CTGF mRNA in HCC with venous invasion were higher than those in HCC without venous invasion. CTGF expression in HCC Edmondson’s grade III-IV was significantly higher than that in HCC Edmondson’s grade I-II (P = 0.022). There was no obvious correlation between Nov mRNA and clinical-pathological features. Compared to NHCC, SLHCC had better cell differentiation, easier capsule formation, less microscopic venous invasion, milder liver cirrhosis. The expressions of Cyr61 and CTGF mRNA in NHCC were significantly higher than those in SLHCC and SHCC.

CONCLUSION: Cyr61 and CTGF genes may play an important role in hepatocellular carcinogenesis and correlate with recurrence and metastasis of hepatocellular carcinoma. SLHCC has better biological behaviors than NHCC.

Desmoplastic melanoma: a diagnostic trap for the unwary

Desmoplastic melanoma (DM) is an uncommon type of spindle cell melanoma in which the malignant cells are separated by collagen fibres or fibrous stroma. DM is prone to misdiagnosis because of unfamiliarity with its often bland appearance and dissimilarity to other conventional types of melanoma. It displays variable cytological atypia, cellularity and stromal fibrosis and more often than not has an accompanying atypical junctional component. Neurotropism is a common associated feature (in at least 30% of cases) and when it occurs such tumours are termed 'desmoplastic neurotropic melanomas' (DNM). The neurotropism may be perineural or intraneural and often extends beyond the desmoplastic component. In addition, some DMs show evidence of neural differentiation ('neural transformation'). DM may also present as a recurrence or occasionally as a metastasis from other types of melanoma. A high index of suspicion and knowledge of its often subtle morphological appearance are necessary to avoid misdiagnosis.