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

Characterization of gastric cancer-stimulated signaling pathways and function of CTGF in cancer-associated fibroblasts

BACKGROUND

Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME) that play an important role in cancer progression. Although the mechanism by which CAFs promote tumorigenesis has been well investigated, the underlying mechanism of CAFs activation by neighboring cancer cells remains elusive. In this study, we aim to investigate the signaling pathways involved in CAFs activation by gastric cancer cells (GC) and to provide insights into the therapeutic targeting of CAFs for overcoming GC.

METHODS

Alteration of receptor tyrosine kinase (RTK) activity in CAFs was analyzed using phospho-RTK array. The expression of CAFs effector genes was determined by RT-qPCR or ELISA. The migration and invasion of GC cells co-cultured with CAFs were examined by transwell migration/invasion assay.

RESULTS

We found that conditioned media (CM) from GC cells could activate multiple receptor tyrosine kinase signaling pathways, including ERK, AKT, and STAT3. Phospho-RTK array analysis showed that CM from GC cells activated PDGFR tyrosine phosphorylation, but only AKT activation was PDGFR-dependent. Furthermore, we found that connective tissue growth factor (CTGF), a member of the CCN family, was the most pronouncedly induced CAFs effector gene by GC cells. Knockdown of CTGF impaired the ability of CAFs to promote GC cell migration and invasion. Although the PDGFR-AKT pathway was pronouncedly activated in CAFs stimulated by GC cells, its pharmacological inhibition affected neither CTGF induction nor CAFs-induced GC cell migration. Unexpectedly, the knockdown of SRC and SRC-family kinase inhibitors, dasatinib and saracatinib, significantly impaired CTGF induction in activated CAFs and the migration of GC cells co-cultured with CAFs. SRC inhibitors restored the reduced expression of epithelial markers, E-cadherin and Zonula Occludens-1 (ZO-1), in GC cells co-cultured with CAFs, as well as CAFs-induced aggregate formation in a 3D tumor spheroid model.

CONCLUSIONS

This study provides a characterization of the signaling pathways and effector genes involved in CAFs activation, and strategies that could effectively inhibit it in the context of GC. Video Abstract.

Identification of antisense and sense RNAs of intracrine fibroblast growth factor components as novel biomarkers in colorectal cancer and in silico studies for drug and nanodrug repurposing

INTRODUCTION

Colorectal cancer (CRC) is one of the most malignant tumors and in which various efforts for screening is inconclusive.The intracrine FGF panel, the non-tyrosine kinase receptors (NTKR) FGFs and affiliated antisenses play a pivotal role in FGF signaling.The expression levels of coding and non-coding intracrine FGFs were assessed in CRC donors.Also, substantial costs and slow pace of drug discovery give high attraction to repurpose of previously discovered drugs to new opportunities.

OBJECTIVES

The aim of present study was to evaluate the potential role of the coding and non-coding intracrine FGFs as a new biomarkers for CRC cases and defining drug repurposing to alleviate FGF down regulation.

METHODS

RNA-seq data of colon adenocarcinomas (COAD) was downloaded using TCGA biolinks package in R.The DrugBank database (https://go.drugbank.com/) was used to extract interactions between drugs and candidate genes. A total of 200 CRC patients with detailed criteria were enrolled.RNAs were extracted with TRIzol-based protocol and amplified via LightCycler® instrument.FGF11 and FGF13 proteins validation was performed by used of immunohistochemistry technique in tumor and non-tumoral samples.Pearson's correlation analysis and ROC curve plotted by Prism 8.0 software.

RESULTS

RNA-seq data from TCGA was analyzed by normalizing with edgeR.Differentially expressed gene (DEG) analysis was generated. WCC algorithm extracted the most significant genes with a total of 47 genes. Expression elevation of iFGF antisenses (12AS,13As,14AS) compared with the normal colon tissue were observed (P = 0.0003,P = 0.042,P = 0.026, respectively). Moreover,a significant decrease in expression of the corresponding sense iFGF genes was detected (P < 0.0001).Plotted receiver operating characteristic (ROC) curves for iFGF components' expression showed an area of over 0.70 (FGF11-13: 0.71% and FGF12-14: 0.78%, P < 0.001) for sense mRNA expression, with the highest sensitivity for FGF12 (92.8%) and lowest for FGF11 (61.41%).The artificial intelligence (AI) revealed the valproic acid as a repurposing drug to relief the down regulation of FGF12 and 13 in CRC patients.

CONCLUSION

Intracrine FGFs panel was down regulated versus up regulation of dependent antisenses. Thus, developing novel biomarkers based on iFGF can be considered as a promising strategy for CRC screening.In advanced, valporic acid detected by AI as a repurposing drug which may be applied in clinical trials for CRC treatment.

Prognostic biomarkers and molecular pathways mediating Helicobacter pylori–induced gastric cancer: a network-biology approach

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori–induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori–induced cancer compared with the H. pylori–positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori–induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori–induced GC. However, experimental validation is necessary in the future.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

Unsupervised Hierarchical Clustering Identifies Immune Gene Subtypes in Gastric Cancer

Objectives: The pathogenesis of heterogeneity in gastric cancer (GC) is not clear and presents as a significant obstacle in providing effective drug treatment. We aimed to identify subtypes of GC and explore the underlying pathogenesis. Methods: We collected two microarray datasets from GEO (GSE84433 and GSE84426), performed an unsupervised cluster analysis based on gene expression patterns, and identified related immune and stromal cells. Then, we explored the possible molecular mechanisms of each subtype by functional enrichment analysis and identified related hub genes. Results: First, we identified three clusters of GC by unsupervised hierarchical clustering, with average silhouette width of 0.96, and also identified their related representative genes and immune cells. We validated our findings using dataset GSE84426. Subtypes associated with the highest mortality (subtype 2 in the training group and subtype C in the validation group) showed high expression of SPARC, COL3A1, and CCN. Both subtypes also showed high infiltration of fibroblasts, endothelial cells, hematopoietic stem cells, and a high stromal score. Furthermore, subtypes with the best prognosis (subtype 3 in the training group and subtype A in the validation group) showed high expression of FGL2, DLGAP1-AS5, and so on. Both subtypes also showed high infiltration of CD4+ T cells, CD8+ T cells, NK cells, pDC, macrophages, and CD4+ T effector memory cells. Conclusion: We found that GC can be classified into three subtypes based on gene expression patterns and cell composition. Findings of this study help us better understand the tumor microenvironment and immune milieu associated with heterogeneity in GC and provide practical information to guide personalized treatment.

Connective Tissue Growth Factor in Digestive System Cancers: A Review and Meta-Analysis

Aim

A meta-analysis was conducted to estimate the impact of connective tissue growth factor (CTGF) on outcomes in patients with digestive system cancers.

Methods

A systemic literature survey was performed by searching the Cochrane Library and PubMed databases for articles that evaluated the impact of CTGF on outcomes in patients with digestive system cancers. Hazard ratios and 95% confidence intervals were calculated for prognostic factors, overall and recurrence-free survival using RevMan 5.3 software.

Results

This meta-analysis was conducted to evaluate a total of 11 studies that included 1730 patients. The results showed that elevated CTGF expression was significantly correlated with advanced age, larger tumor size, multiple tumors, and vascular invasion. Subgroup analysis by cancer type revealed increased risk for lymph node metastasis and advanced tumor node metastasis (TNM) stage in gastric cancer, compared with colorectal cancer. An unfavorable effect of elevated CTGF levels on overall survival was found in patients with hepatocellular carcinoma and patients with gastric cancer, while survival was improved in colorectal cancer patients with high CTGF expression, compared to those with normal levels of CTGF.

Conclusions

Elevated CTGF expression may be a novel biomarker for disease status and predicted survival outcomes in patients with specific digestive system cancers.

Connective Tissue Growth Factor: From Molecular Understandings to Drug Discovery

Connective tissue growth factor (CTGF) is a key signaling and regulatory molecule involved in different biological processes, such as cell proliferation, angiogenesis, and wound healing, as well as multiple pathologies, such as tumor development and tissue fibrosis. Although the underlying mechanisms of CTGF remain incompletely understood, a commonly accepted theory is that the interactions between different protein domains in CTGF and other various regulatory proteins and ligands contribute to its variety of functions. Here, we highlight the structure of each domain of CTGF and its biology functions in physiological conditions. We further summarized main diseases that are deeply influenced by CTGF domains and the potential targets of these diseases. Finally, we address the advantages and disadvantages of current drugs targeting CTGF and provide the perspective for the drug discovery of the next generation of CTGF inhibitors based on aptamers.

The Extracellular Matrix: An Accomplice in Gastric Cancer Development and Progression

The extracellular matrix (ECM) is a dynamic and highly organized tissue structure, providing support and maintaining normal epithelial architecture. In the last decade, increasing evidence has emerged demonstrating that alterations in ECM composition and assembly strongly affect cellular function and behavior. Even though the detailed mechanisms underlying cell-ECM crosstalk are yet to unravel, it is well established that ECM deregulation accompanies the development of many pathological conditions, such as gastric cancer. Notably, gastric cancer remains a worldwide concern, representing the third most frequent cause of cancer-associated deaths. Despite increased surveillance protocols, patients are usually diagnosed at advanced disease stages, urging the identification of novel diagnostic biomarkers and efficient therapeutic strategies. In this review, we provide a comprehensive overview regarding expression patterns of ECM components and cognate receptors described in normal gastric epithelium, pre-malignant lesions, and gastric carcinomas. Important insights are also discussed for the use of ECM-associated molecules as predictive biomarkers of the disease or as potential targets in gastric cancer.

Overexpression of connective tissue growth factor is associated with tumor progression and unfavorable prognosis in endometrial cancer

OBJECTIVES

This study was to explore the prognostic value of connective tissue growth factor (CTGF) expression in endometrial cancer (EC).

METHODS

We compared CTGF expression in 198 samples from patients with endometrial cancer and 50 samples from patients with healthy endometrial tissues as determined by immunohistochemistry.

RESULTS

Expression of CTGF was significantly higher in endometrial cancers as compared to normal endometrial tissues. Positive CTGF expression displayed a strong association with CA125 level, histological grade, depth of myometrial invasion and the International Federation of Gynecology and Obstetrics (FIGO) stage. Our findings revealed histological grade, depth of myometrial invasion, FIGO stage, vascular/lymphatic invasion, and the CTGF expression are related to 5-year survival in patients with endometrial cancer. Positive CTGF expression, lymph node status, as well as vascular/lymphatic invasion, were identified as independent prognostic factors in endometrial cancer.

CONCLUTIONS

Over-expression of CTGF is an independent prognostic factor that will allow the successful differentiation of high-risk population from the group of patients with stage III-IV endometrial cancer. The up-regulation of CTGF may contribute to the progression of endometrial cancer and serve as a new prognostic biomarker in patients with endometrial cancer survival.

Down-regulation of interferon regulatory factor 2 binding protein 2 suppresses gastric cancer progression by negatively regulating connective tissue growth factor

Interferon regulatory factor 2 binding protein 2 (IRF2BP2) is a transcriptional repressor involved in regulating gene expression and other biological processes, including tumorigenesis. However, the clinical significance and roles of IRF2BP2 in human gastric cancer (GC) remain uncertain. Clinical GC tissues were obtained from GC patients at the First Affiliated Hospital of Nanchang University. Immunohistochemistry (IHC) was conducted to detect the IRF2BP2 protein in clinical paraffin specimens. Cell proliferation, migration and invasion were evaluated by MTT, colony formation assays and transwell assays. Co-immunoprecipitation was conducted to detect the interaction between TEA domain family members 4 (TEAD4) and vestigial-like family member 4 (VGLL4) or Yes-associated protein 1 (YAP1). Dual-luciferase reporter assay was used to confirm the binding of miR-101-3p to the 3'-UTR. The expression of IRF2BP2 was significantly higher in GC tissues than in normal tissues. Patients with higher IRF2BP2 protein expression had lower survival. IRF2BP2 knockdown inhibited proliferation, migration, invasion and epithelial-mesenchymal transition in GC cells. IRF2BP2 knockdown decreased the mRNA and protein levels of connective tissue growth factor (CTGF). The interaction between IRF2BP2 and VGLL4 increased the binding of TEAD4 to YAP1, resulting in the transcriptional coactivation of CTGF. In addition, miR-101-3p suppressed the expression of CTGF by directly targeting the 3'-UTR of IRF2BP2. Taken together, these findings provide a model for the role of miR-101-3p-IRF2BP2-CTGF signalling axis in GC and a novel insight into the mechanism of GC progression and metastasis.

MiR-218 regulates epithelial-mesenchymal transition and angiogenesis in colorectal cancer via targeting CTGF

Background

Endothelial-to-mesenchymal transition (EMT) and angiogenesis play important roles in colorectal cancer (CRC) development. Connective tissue growth factor (CTGF) has been reported to promote several kinds of cancer progression and miR-218 has been identified as a tumor suppressor miRNA. However, little is known about the function of miR-218 in CRC. Here we investigated the effects of miR-218 on EMT and angiogenesis process in CRC cells. As well, the relation between miR-218 and CTGF was identified. The mechanism of miR-218’s function was illustrated.

Methods

CRC cell lines were transfected with miR-218 mimics. Proliferation, migration and angiogenesis were identified by MTT assay, Transwell assay, colony formation assay and tube formation assay. Protein and mRNA expression levels of associated genes were measured by Western blotting and RT-PCR. Dual luciferase assay was used to determine the relation of miR-218 and CTGF.

Results

miR-218 was down-regulated in CRC cell lines and over expression of miR-218 could significantly inhibit EMT and angiogenesis. CTGF was a direct target of miR-218. Up regulation of CTGF level after miR-218 transfection could sufficiently rescue the suppression effects on EMT and angiogenesis.

Conclusion

miR-218 directly targets CTGF and inhibits its expression, leading to suppression on EMT and angiogenesis of CRC cells. miR-218 might be used as potential therapeutic strategy for CRC treatment.

miR-221 stimulates breast cancer cells and cancer-associated fibroblasts (CAFs) through selective interference with the A20/c-Rel/CTGF signaling

Background

MicroRNA (miRNAs) are non-coding small RNA molecules that regulate gene expression by inhibiting the translation of target mRNAs. Among several dysregulated miRNAs in human cancer, the up-regulation of miR-221 has been associated with development of a variety of hematologic and solid malignancies. In this study, we investigated the involvement of miR-221 in breast cancer.

Methods

TaqMan microRNA assay was used to detect the miR-221 levels in normal cells and in MDA-MB 231 and SkBr3 breast cancer cells as well as in main players of the tumor microenvironment, namely cancer-associated fibroblasts (CAFs). miR-221 mimic sequence and locked nucleic acid (LNA)-i-miR-221 construct were used to induce or inhibit, respectively, the miR-221 expression in cells used. Quantitative PCR and western blotting analysis were performed to evaluate the levels of the miR-221 target gene A20 (TNFAIP3), as well as the member of the NF-kB complex namely c-Rel and the connective tissue growth factor (CTGF). Chromatin immunoprecipitation (ChIP) assay was performed to ascertain the recruitment of c-Rel to the CTFG promoter. Finally, the cell growth and migration in the presence of LNA-i-miR-221 or silencing c-Rel and CTGF by specific short hairpin were assessed by cell count, colony formation and boyden chambers assays. Statistical analysis was performed by ANOVA.

Results

We first demonstrated that LNA-i-miR-221 inhibits both endogenous and ectopic expression of miR-221 in our experimental models. Next, we found that the A20 down-regulation, as well as the up-regulation of c-Rel induced by miR-221 were no longer evident using LNA-i-miR-221. Moreover, we established that the miR-221 dependent recruitment of c-Rel to the NF-kB binding site located within the CTGF promoter region is prevented by using LNA-i-miR-221. Furthermore, we determined that the up-regulation of CTGF mRNA and protein levels by miR-221 is no longer evident using LNA-i-miR221 and silencing c-Rel. Finally, we assessed that cell growth and migration induced by miR-221 in MDA-MB 231 and SkBr3 breast cancer cells as well as in CAFs are abolished by LNAi-miR-221 and silencing c-Rel or CTGF.

Conclusions

Overall, these data provide novel insights into the stimulatory action of miR-221 in breast cancer cells and CAFs, suggesting that its inhibition may be considered toward targeted therapeutic approaches in breast cancer patients.

The Hippo pathway as a drug target in gastric cancer

The Hippo tumor suppressor pathway is critical for balancing cellular differentiation and proliferation in response to cell-cell contact, mechanical signals and diffusible signals such as lysophosphatidic acid. Hippo pathway signaling is frequently dysregulated in gastric cancer (GC), as well as many other kinds of solid tumors, contributing to multiple aspects of malignant progression including unchecked cell division and metastasis. Considering the importance of this Hippo pathway in cancer, its pharmacological disruption may be of huge benefit in the fight against this disease. In this review, we summarize the components of the Hippo pathway, its crosstalk with other major oncogenic signaling pathways, common mechanisms of its dysregulation, as well as potential therapeutic approaches of targeting this pathway for cancer treatment, specifically in a GC context.

miR-375 is involved in Hippo pathway by targeting YAP1/TEAD4-CTGF axis in gastric carcinogenesis

miR-375 is a tumor-suppressive microRNA (miRNA) in gastric cancer (GC). However, its molecular mechanism remains unclear. The aim of this study is to comprehensively investigate how miR-375 is involved in Hippo pathway by targeting multiple oncogenes. miR-375 expression in gastric cancer cell lines and primary GC was investigated by qRT-PCR. The regulation of YAP1, TEAD4, and CTGF expression by miR-375 was evaluated by qRT-PCR, western blot, and luciferase reporter assays, respectively. The functional roles of the related genes were examined by siRNA-mediated knockdown or ectopic expression assays. The clinical significance and expression correlation analysis of miR-375, YAP1, and CTGF were performed in primary GCs. TCGA cohort was also used to analyze the expression correlation of YAP1, TEAD4, CTGF, and miR-375 in primary GCs. miR-375 was down-regulated in GC due to promoter methylation and histone deacetylation. miR-375 downregulation was associated with unfavorable outcome and lymph node metastasis. Ectopic expression of miR-375 inhibited tumor growth in vitro and in vivo. Three components of Hippo pathway, YAP1, TEAD4 and CTGF, were revealed to be direct targets of miR-375. The expression of three genes showed a negative correlation with miR-375 expression and YAP1 re-expression partly abolished the tumor-suppressive effect of miR-375. Furthermore, CTGF was confirmed to be the key downstream of Hippo-YAP1 cascade and its knockdown phenocopied siYAP1 or miR-375 overexpression. YAP1 nuclear accumulation was positively correlated with CTGF cytoplasmic expression in primary GC tissues. Verteporfin exerted an anti-oncogenic effect in GC cell lines by quenching CTGF expression through YAP1 degradation. In short, miR-375 was involved in the Hippo pathway by targeting YAP1-TEAD4-CTGF axis and enriched our knowledge on the miRNA dysregulation in gastric tumorigenesis.

A potential role for CCN2/CTGF in aggressive colorectal cancer

CCN2, also known as connective tissue growth factor (CTGF) is a transcriptional target of TGF-β signaling. Unlike its original name (“CTGF”) suggested, CCN2 is not an actual growth factor but a matricellular protein that plays an important role in fibrosis, inflammation and connective tissue remodeling in a variety of diseases, including cancer. In pancreatic ductal adenocarcinoma, CCN2 signaling induces stromal infiltration and facilitates a strong tumor-stromal interaction. In many types of cancer, CCN2 overexpression has been associated with poor outcome. CMS4 (Consensus Molecular Subtype 4) is a recently identified aggressive colorectal cancer subtype, that is characterized by up-regulation of genes involved in epithelial-to-mesenchymal transition, TGF-β signaling, angiogenesis, complement activation, and extracellular matrix remodeling. In addition, a high influx of stromal fibroblasts contributes to the mesenchymal-like gene expression profile of this subtype. Furthermore, compared with the other three CMS groups, CMS4 tumors have the worst prognosis. Based on these observations, we postulated that CCN2 might contribute to colorectal cancer progression, especially in the CMS4 subtype. This review discusses the available literature on the role of CCN2 in colorectal cancer, with a focus on the ‘fibrotic subtype’ CMS4.

Differential expression of CCN family members CYR611, CTGF and NOV in gastric cancer and their association with disease progression

CCN is an acronym for cysteine-rich protein 61 (CYR61), connective tissue growth factor (CTGF) and nephroblastoma overexpressed (NOV). Aberrations of certain CCN members including CYR61, CTGF, Wnt1-inducible signalling pathway protein (WISP)-1 and -3 have been reported in gastric cancer. The present study aimed to examine the clinical relevance of NOV along with CYR61 and CTGF in gastric cancer by analysing their transcript levels. CYR61, CTGF and NOV transcript expression in 324 gastric cancer samples with paired adjacent normal gastric tissues were determined using real-time quantitative PCR and the results were statistically analysed against patient clinicopathological data using SPSS software. NOV mRNA levels in gastric cancer tissues were significantly elevated when compared with levels in their paired adjacent non-cancerous tissues. Local advanced tumours with invasive expansion (T3 and T4) expressed higher levels of NOV (p=0.013) compared with the less invasive tumours (T1 and T2). CYR61 transcript levels were also significantly increased in gastric cancers compared with levels in the adjacent non-cancerous tissues. Kaplan-Meier survival curves revealed that patients with CYR61-low transcript levels had longer overall survival (OS) (p=0.018) and disease-free survival (DFS) (p=0.015). NOV overexpression promoted the in vitro proliferation of AGS cells while the knockdown resulted in a reduced proliferation of HGC27 cells. A similar effect was observed for the invasion of these two gastric cancer cell lines. NOV expression was increased in gastric cancer which was associated with local invasion and distant metastases. Taken together, the expression of NOV and CYR61 was increased in gastric cancer. The elevated expression of CYR61 was associated with poorer survival. NOV promoted proliferation and invasion of gastric cancer cells. Further investigations may highlight their predictive and therapeutic potential in gastric cancer.

Decreased expression of connective tissue growth factor in non-small cell lung cancer is associated with clinicopathological variables and can be restored by epigenetic modifiers

Purpose

Recent studies indicated undisputed contribution of connective tissue growth factor (CTGF) in the development of many cancers, including non-small cell lung cancer (NSCLC). However, the functional role and regulation of CTGF expression during tumorigenesis remain elusive. Our goal was to determine CTGF transcript and protein levels in tumoral and matched control tissues from 98 NSCLC patients, to correlate the results with clinicopathological features and to investigate whether the CTGF expression can be epigenetically regulated in NSCLC.

Methods

We used quantitative PCR, Western blotting and immunohistochemistry to evaluate CTGF expression in lung cancerous and histopathologically unchanged tissues. We tested the impact of 5-Aza-2′-deoxycytidine (5-dAzaC) and trichostatin A (TSA) on CTGF transcript and protein levels in NSCLC cells (A549, Calu-1). DNA methylation status of the CTGF regulatory region was evaluated by bisulfite sequencing. The influence of 5-dAzaC and TSA on NSCLC cells viability and proliferation was monitored by the trypan blue assay.

Results

We found significantly decreased levels of CTGF mRNA and protein (both p < 0.0000001) in cancerous tissues of NSCLC patients. Down-regulation of CTGF occurred regardless of gender in all histological subtypes of NSCLC. Moreover, we showed that 5-dAzaC and TSA were able to restore CTGF mRNA and protein contents in NSCLC cells. However, no methylation within CTGF regulatory region was detected. Both compounds significantly reduced NSCLC cells proliferation.

Conclusions

Decreased expression of CTGF is a common feature in NSCLC; however, it can be restored by the chromatin-modifying agents such as 5-dAzaC or TSA and consequently restrain cancer development.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-016-2195-3) contains supplementary material, which is available to authorized users.

Connective tissue growth factor is activated by gastrin and involved in gastrin-induced migration and invasion

Connective tissue growth factor (CTGF) has been reported in gastric adenocarcinoma and in carcinoid tumors. The aim of this study was to explore a possible link between CTGF and gastrin in gastric epithelial cells and to study the role of CTGF in gastrin induced migration and invasion of AGS-GR cells. The effects of gastrin were studied using RT-qPCR, Western blot and assays for migration and invasion. We report an association between serum gastrin concentrations and CTGF abundancy in the gastric corpus mucosa of hypergastrinemic subjects and mice. We found a higher expression of CTGF in gastric mucosa tissue adjacent to tumor compared to normal control tissue. We showed that gastrin induced expression of CTGF in gastric epithelial AGS-GR cells via MEK, PKC and PKB/AKT pathways. CTGF inhibited gastrin induced migration and invasion of AGS-GR cells. We conclude that CTGF expression is stimulated by gastrin and involved in remodeling of the gastric epithelium.

Structural ECM components in the premetastatic and metastatic niche

The aim of this review is to give an overview of the extracellular matrix (ECM) components that are important for creating structural changes in the premetastatic and metastatic niche. The successful arrival and survival of cancer cells that have left the primary tumor and colonized distant sites depends on the new microenvironment they encounter. The primary tumor itself releases factors into the circulation that travel to distant organs and then initiate structural changes, both non-enzymatic and enzymatic, to create a favorable niche for the disseminating tumor cells. Therapeutic strategies aimed at targeting cell-ECM interactions may well be one of the best viable approaches to combat metastasis and thus improve patient care.

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.

Expression and clinical significance of connective tissue growth factor in advanced head and neck squamous cell cancer

Connective tissue growth factor (CTGF) has been reported to play critical roles in the tumorigenesis of several human malignancies. This study was performed to evaluate CTGF protein expression in head and neck squamous cell carcinoma (HNSCC). Surgical specimens from 76 primary HNSCC were obtained with written informed consents and the expression level of CTGF was immunohistochemically evaluated. The cytoplasmic immunoreactivity of CTGF in cancer cells was semiquantitatively classified into low and high expression. Among all 76 cases with or without neoadjuvant therapy, low CTGF showed significantly longer (P = 0.0282) overall survival (OS), but not disease-free survival (DFS) than high CTGF. Although low CTGF in patients with stage I, II and III did not result in any significant difference of the OS and DFS, stage IV HNSCC patients with low CTGF showed significantly longer OS (P = 0.032) and DFS (P = 0.0107) than those with high CTGF. These differences in stage IV cases were also confirmed using multivariate analyses. These results suggest that low CTGF in stage IV HNSCC is an independent prognostic factor, despite with or without neoadjuvant therapy.

Increased levels of SLP-2 correlate with poor prognosis in gastric cancer

BACKGROUND

Stomatin-like protein 2 (SLP-2) is a member of the highly conserved stomatin protein family whose homologues span from Archaea to humans and include stomatin, SLP-1, and SLP-3. Several studies have indicated that overexpression of SLP-2 is strongly associated with adhesion and migration in several human cancers. The aim of the present study was to evaluate SLP-2 expression at the mRNA and protein level in patients with gastric cancer (GC) and to examine the relationships between SLP-2 expression, clinicopathological features, and prognosis.

METHODS

We investigated SLP-2 expression in primary GC and paired normal gastric tissue by real-time PCR (RT-PCR; n = 16) and Western blot analysis (n = 32). Additionally, we performed immunohistochemistry (IHC) on 113 paraffin-embedded GC specimens, 30 matched normal specimens, and 30 paired metastatic lymph node samples.

RESULTS

SLP-2 is overexpressed in GC compared with the adjacent normal gastric epithelium (p < 0.001), and high-level SLP-2 expression is significantly correlated with the depth of invasion, lymph node metastasis, distant metastasis, and American Joint Committee on Cancer (AJCC) stage. Furthermore, elevated SLP-2 expression is an independent prognostic factor in multivariate analysis using the Cox regression model (p = 0.005).

CONCLUSIONS

Overexpression of SLP-2 may contribute to the progression and poor prognosis of GC.

Clinicopathological significance of SLP-2 overexpression in human gallbladder cancer

Several studies have indicated that overexpression of stomatin-like protein 2 (SLP-2) has been identified in several types of cancer. However, its role and clinical relevance in gallbladder cancer (GBC) is unknown. The purpose of this study was to reveal the prognostic significance of SLP-2 in GBC. The SLP-2 expression was examined at mRNA and protein levels by real-time quantitative polymerase chain reaction (qRT-PCR), and immunohistochemistry in GBC tissues and adjacent noncancerous tissues. Statistical analyses were applied to test the associations between SLP-2 expression, clinicopathologic factors, and prognosis. Immunohistochemistry and qRT-PCR showed that the protein and mRNA expression levels of SLP-2 were both significantly higher in GBC tissues than in adjacent noncancerous tissues. In addition, immunohistochemistry analysis showed that SLP-2 expression was significantly correlated with histological grade (P <0.001), pathologic T stage (P = 0.019), clinical stage (P = 0.001), and lymph node metastasis (P = 0.026). The Kaplan-Meier survival curves indicated that patients with high expression of SLP-2 had shorter overall survival than those with low expression (P <0.001). Meanwhile, the Cox multivariate analysis indicated that high expressions of SLP-2 were an independent prognostic factor for patients with GBC. These data showed that SLP-2 may play an important role in human GBC tumorigenesis, and SLP-2 might serve as a novel prognostic marker in human GBC.

Inhibition of connective tissue growth factor (CTGF/CCN2) in gallbladder cancer cells leads to decreased growth in vitro

Gallbladder cancer (GBC) is an aggressive neoplasm associated with late diagnosis, unsatisfactory treatment and poor prognosis. Previous work showed that connective tissue growth factor (CTGF) expression is increased in this malignancy. This matricellular protein plays an important role in various cellular processes and its involvement in the tumorigenesis of several human cancers has been demonstrated. However, the precise function of CTGF expression in cancer cells is yet to be determined. The aim of this study was to evaluate the CTGF expression in gallbladder cancer cell lines, and its effect on cell viability, colony formation and in vitro cell migration. CTGF expression was evaluated in seven GBC cell lines by Western blot assay. Endogenous CTGF expression was downregulated by lentiviral shRNA directed against CTGF mRNA in G-415 cells, and the effects on cell viability, anchorage-independent growth and migration was assessed by comparing them to scrambled vector-transfected cells. Knockdown of CTGF resulted in significant reduction in cell viability, colony formation and anchorage-independent growth (P < 0.05). An increased p27 expression was observed in G-415 cells with loss of CTGF function. Our results suggest that high expression of this protein in gallbladder cancer may confer a growth advantage for neoplastic cells.

Connective tissue growth factor immunohistochemical expression is associated with gallbladder cancer progression

CONTEXT

Gallbladder cancer (GBC) is an aggressive neoplasia associated with late diagnosis, unsatisfactory treatment, and poor prognosis. Molecular mechanisms involved in GBC pathogenesis remain poorly understood. Connective tissue growth factor (CTGF) is thought to play a role in the pathologic processes and is overexpressed in several human cancers, including GBC. No information is available about CTGF expression in early stages of gallbladder carcinogenesis. Objective.- To evaluate the expression level of CTGF in benign and malignant lesions of gallbladder and its correlation with clinicopathologic features and GBC prognosis.

DESIGN

Connective tissue growth factor protein was examined by immunohistochemistry on tissue microarrays containing tissue samples of chronic cholecystitis (n = 51), dysplasia (n = 15), and GBC (n = 169). The samples were scored according to intensity of staining as low/absent and high CTGF expressers. Statistical analysis was performed using the χ(2) test or Fisher exact probability test with a significance level of P < .05. Survival analysis was assessed by the Kaplan-Meier method and the log-rank test.

RESULTS

Connective tissue growth factor expression showed a progressive increase from chronic cholecystitis to dysplasia and then to early and advanced carcinoma. Immunohistochemical expression (score ≥2) was significantly higher in advanced tumors, in comparison with chronic cholecystitis (P < .001) and dysplasia (P = .03). High levels of CTGF expression correlated with better survival (P = .04).

CONCLUSIONS

Our results suggest a role for CTGF in GBC progression and a positive association with better prognosis. In addition, they underscore the importance of considering the involvement of inflammation on GBC development.

CTGF is a therapeutic target for metastatic melanoma

Metastatic melanoma remains a devastating disease with a 5-year survival rate of less than five percent. Despite recent advances in targeted therapies for melanoma, only a small percentage of melanoma patients experience durable remissions. Therefore, it is critical to identify new therapies for the treatment of advanced melanoma. Here, we define connective tissue growth factor (CTGF) as a therapeutic target for metastatic melanoma. Clinically, CTGF expression correlates with tumor progression and is strongly induced by hypoxia through HIF-1 and HIF-2-dependent mechanisms. Genetic inhibition of CTGF in human melanoma cells is sufficient to significantly reduce orthotopic tumor growth, as well as metastatic tumor growth in the lung of severe combined immunodeficient (SCID) mice. Mechanistically, inhibition of CTGF decreased invasion and migration associated with reduced matrix metalloproteinase-9 expression. Most importantly, the anti-CTGF antibody, FG-3019, had a profound inhibitory effect on the progression of established metastatic melanoma. These results offer the first preclinical validation of anti-CTGF therapy for the treatment of advanced melanoma and underscore the importance of tumor hypoxia in melanoma progression.

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.

GPER mediates the Egr-1 expression induced by 17β-estradiol and 4-hydroxitamoxifen in breast and endometrial cancer cells

Early growth response-1 (Egr-1) is an immediate early gene involved in relevant biological events including the proliferation of diverse types of cell tumors. In a microarray analysis performed in breast cancer cells, 17β-estradiol (E2) and the estrogen receptor antagonist 4-hydroxitamoxifen (OHT) up-regulated Egr-1 through the G protein-coupled receptor named GPR30/GPER. Hence, in this study, we aimed to provide evidence regarding the ability of E2, OHT and the selective GPER ligand G-1 to regulate Egr-1 expression and function through the GPER/EGFR/ERK transduction pathway in both Ishikawa (endometrial) and SkBr3 (breast) cancer cells. Interestingly, we demonstrate that Egr-1 is involved in the transcription of genes regulating cell proliferation like CTGF and cyclin D1 and required for the proliferative effects induced by E2, OHT, and G-1 in both Ishikawa and SkBr3 cells. In addition, we show that GPER mediates the expression of Egr-1 also in carcinoma-associated fibroblasts (CAFs). Our data suggest that Egr-1 may represent an important mediator of the biological effects induced by E2 and OHT through GPER/EGFR/ERK signaling in breast and endometrial cancer cells. The results obtained in CAFs provide further evidence regarding the potential role exerted by the GPER-dependent Egr-1 up-regulation in tumor development and progression. Therefore, Egr-1 may be included among the bio-markers of estrogen and antiestrogen actions and may be considered as a further therapeutic target in both breast and endometrial tumors.

Oral application of 1,7-dimethylxanthine (paraxanthine) attenuates the formation of experimental cholestatic liver fibrosis

AIM

  Several epidemiological studies suggest a beneficial effect of coffee consumption on the formation and progression of fibrogenic diseases, particularly of the liver. Recent data now point to a modulation of transforming growth factor-β (TGF-β) signaling by paraxanthine (1,7-dimethylxanthine [1,7-DMX]), the demethylated primary metabolite of caffeine

METHODS

  Twenty adult Sprague-Dawley rats were bile duct ligated (BDL) or sham operated with or without concomitant oral 1,7-DMX (1 mM) application. Serum was investigated by standard biochemical analysis, in-house connective tissue growth factor (CTGF), enzyme linked immunosorbent assay (ELISA) or liquid chromatography-mass spectrometry analysis. Liver tissue was stained using hematoxylin-eosin (HE) and Sirius-red staining. Whole liver lysates, primary rat hepatocytes (PC) and hepatic stellate cells (HSC) were investigated by CTGF, and total Smad2/3 Western blot analysis, CTGF reporter gene assay or an in-house malondialdehyde ELISA.

RESULTS

  The in vitro 50% inhibitory dose (ID50) of 1,7-DMX was 0.95 mM by for CTGF promoter activity and protein expression in PC and 1.25 mM for protein expression in HSC. Oral 1,7-DMX application (1 mM) attenuated cholestatic hepatocellular injury in vivo as determined by biochemical serum analysis and reduced intercellular collagen deposition in the cholestatic rat liver (HE- and Sirius-red staining). Western Blot analysis of whole liver lysates revealed a reduction of intrahepatic concentrations of Smad2/3 and CTGF following oral 1,7-DMX intake. However, serum CTGF concentrations were not reduced in 1,7-DMX treated BDL rats. Oral 1,7-DMX furthermore led to a reduction of intrahepatic lipid peroxidation (malondialdehyde concentrations) as markers of oxidative stress in BDL rats.

CONCLUSION

  Our pilot study warrants further studies of 1,7-DMX as a potential new drug to fight fibrotic processes, not just of the liver.

Downregulation of connective tissue growth factor inhibits the growth and invasion of gastric cancer cells and attenuates peritoneal dissemination

Background

Connective tissue growth factor (CTGF) has been shown to be implicated in tumor development and progression. However, the role of CTGF in gastric cancer remains largely unknown.

Results

In this study, we showed that CTGF was highly expressed in gastric cancer tissues compared with matched normal gastric tissues. The CTGF expression in tumor tissue was associated with histologic grade, lymph node metastasis and peritoneal dissemination (P < 0.05). Patients with positive CTGF expression had significantly lower cumulative postoperative 5 year survival rate than those with negative CTGF expression (22.9% versus 48.1%, P < 0.001). We demonstrated that knockdown of CTGF expression significantly inhibited cell growth of gastric cancer cells and decreased cyclin D₁ expression. Moreover, knockdown of CTGF expression also markedly reduced the migration and invasion of gastric cancer cells and decreased the expression of matrix metalloproteinase (MMP)-2 and MMP-9. Animal studies revealed that nude mice injected with the CTGF knockdown stable cell lines featured a smaller number of peritoneal seeding nodules than the control cell lines.

Conclusions

These data suggest that CTGF plays an important role in cell growth and invasion in human gastric cancer and it appears to be a potential prognostic marker for patients with gastric cancer.

Metastasis-suppressor genes in clinical practice: lost in translation?

Over the past 25 years, an expanding set of metastasis-suppressor genes (MSGs) has been identified that specifically regulate metastasis formation without affecting primary growth. MSGs are involved in diverse molecular processes in multiple tumor types. Given the wealth of metastasis biology that underlies their functions, treatment strategies based on MSGs have an unparalleled potential to improve patient care. Using NM23 as a prime example, we discuss how specific MSGs have been used as prognostic markers, tools for predicting response to treatment, and targets for the development of novel therapies. Barriers specific to the translation of MSG biology into clinical practice are reviewed and future research directions necessary for clinical advances are delineated. Although to date the impact of MSGs on patient care is limited, it is an expanding field with vast potential to help develop new treatments and identify patients who will most benefit from them.

CTGF is overexpressed in papillary thyroid carcinoma and promotes the growth of papillary thyroid cancer cells

Connective tissue growth factor (CTGF or CCN2), which belongs to the CCN family, is a secreted protein. It has been implicated in various biological processes, such as cell proliferation, migration, angiogenesis, and tumorigenesis. In this study, we found that CTGF expression level was elevated in primary papillary thyroid carcinoma (PTC) samples and correlated with clinical features, such as metastasis, tumor size, and clinical stage. Overexpression of CTGF in PTC cells accelerated their growth in liquid culture and soft agar as well as protecting PTC cells from apoptosis induced by IFN-gamma treatment. Downregulation of CTGF in PTC cells inhibits cell growth in liquid culture and soft agar and induces the activation of caspase pathway and sensitized PTC cells to apoptosis. Our data suggest that CTGF plays an important role in PTC progression by supporting tumor cell survival and drug resistance, and CTGF may be used as a potential tumor marker for PTC diagnosis.

Forkhead transcription factor foxq1 promotes epithelial-mesenchymal transition and breast cancer metastasis

Epithelial-mesenchymal transition (EMT) promotes cancer invasion and metastasis, but the integrative mechanisms that coordinate these processes are incompletely understood. In this study, we used a cross-species expression profiling strategy in metastatic cell lines of human and mouse origin to identify 22 up-regulated and 12 down-regulated genes that are part of an essential genetic program in metastasis. In particular, we identified a novel function in metastasis that was not previously known for the transcription factor Forkhead Box Q1 (Foxq1). Ectopic expression of Foxq1 increased cell migration and invasion in vitro, enhanced the lung metastatic capabilities of mammary epithelial cells in vivo, and triggered a marked EMT. In contrast, Foxq1 knockdown elicited converse effects on these phenotypes in vitro and in vivo. Neither ectopic expression nor knockdown of Foxq1 significantly affected cell proliferation or colony formation in vitro. Notably, Foxq1 repressed expression of the core EMT regulator E-cadherin by binding to the E-box in its promoter region. Further mechanistic investigation revealed that Foxq1 expression is regulated by TGF-β1, and that Foxq1 knockdown blocked TGF-β1-induced EMT at both morphological and molecular levels. Our findings highlight the feasibility of cross-species expression profiling as a strategy to identify metastasis-related genes, and they reveal that EMT induction is a likely mechanism underlying a novel metastasis-promoting function of Foxq1 defined here in breast cancer.

Significance of serum connective tissue growth factor in patients with hepatocellular carcinoma and relationship with angiogenesis

BACKGROUND

Connective tissue growth factor (CTGF) expression changes variously in different human malignancies. The role of CTGF in hepatocellular carcinoma (HCC) is still not clear. The purpose of this study was to investigate the role of serum CTGF in patients with HCC and its correlation with HCC angiogenesis.

METHODS

CTGF, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) were measured by ELISA in preoperative sera of 88 patients with HCC with tumor resection and 39 healthy subjects. The relationship between CTGF and HCC clinicopathological parameters was observed. Prognostic significance of CTGF for survival of patients with HCC was assessed by Kaplan-Meier analysis.

RESULTS

Preoperative serum CTGF level was significantly higher in patients with HCC than in healthy subjects (median, 63.5 vs. 11.4 ng/ml; P < 0.001). Serum CTGF correlated significantly with a series of clinicopathological parameters (big tumor size, advanced pathological tumor-node-metastasis stage, absence of tumor capsule, portal vein invasion). Serum CTGF showed a significant correlation with disease-free survival and overall survival of patients with HCC. Patients with high serum CTGF (>63.5 ng/ml) had a poorer disease-free survival time than the others (CTGF < or = 63.5 ng/ml; median disease-free survival time, 9.6 vs. 19.3 months). Patients with high serum CTGF had poorer overall survival time (median, 13.1 months) than the others (median, 21.7 months). In multivariate Cox analysis, CTGF was identified as an independent and significant prognostic factor of survival of HCC patients.

CONCLUSIONS

Serum CTGF plays an important role in the progression of HCC. Serum CTGF may be a potential indicator of angiogenesis of HCC.

Connective tissue growth factor associated with oncogenic activities and drug resistance in glioblastoma multiforme

Connective tissue growth factor (CTGF or CCN2) is a secreted protein that belongs to the CCN [cysteine-rich CYR61/CTGF/nephroblastoma-overexpressed gene] family. These proteins have been implicated in various biological processes, including stimulation of cell proliferation, migration, angiogenesis and tumorigenesis. In a previous study, we found that CTGF mRNA was elevated in primary gliomas, and a significant correlation existed between CTGF mRNA levels versus tumor grade, histology and patient survival. In this study, the role of CTGF in glioma tumorigenesis was explored. Forced expression of CTGF in glioblastoma multiforme (GBM) cells accelerated their growth in liquid culture and soft agar, stimulated cells migration in Boyden chamber assays and significantly increased their ability to form large, vascularized tumors in nude mice. CTGF induced the expression of the antiapoptotic proteins, Bcl-xl, Survivin and Flip. Overexpression of CTGF caused the U343 GBM cells to survive for longer than 40 days in serum-free medium and resist antitumor drugs including tumor necrosis factor (TNF), TNF-related apoptosis-inducing ligand, VELCADE (bortezomib, proteasome inhibitor) and temozolomide. Our data suggest that CTGF plays an important role in glioma progression, by supporting tumor cells survival and drug resistance.

Nuclear alternate estrogen receptor GPR30 mediates 17beta-estradiol-induced gene expression and migration in breast cancer-associated fibroblasts

Fibroblasts are the principal cellular component of connective tissue and are associated with cancer cells at all stages of tumor progression. Structural and functional contributions of fibroblasts to the growth, survival, and invasive capacity of cancer cells are beginning to emerge. In breast carcinoma, approximately 80% of stromal fibroblasts termed cancer-associated fibroblasts (CAF) are thought to manifest an activated phenotype that promotes cancer cell proliferation tumor growth at metastatic sites similar to the primary tumor. In this report, we show that CAFs respond to physiologic concentrations of 17beta-estradiol (E2) by rapidly inducing extracellular signal-regulated kinase phosphorylation and immediate early gene expression, including c-fos and connective tissue growth factor, and cyclin D1. Notably, the E2 response is mediated by the alternate estrogen receptor GPR30, which interfaces with the epidermal growth factor receptor (EGFR) signaling pathway. In particular, E2 stimulates a physical interaction between GPR30 and phosphorylated EGFR, recruiting them to the cyclin D1 gene promoter. Nuclear localization induced by E2 was confirmed by cellular immunofluorescence methods. GPR30 was required for CAF proliferation and migration induced by E2. Our results provide important new mechanistic insights into how CAFs are stimulated by estrogen through a GPR30-mediated nuclear signaling pathway. More generally, they define estrogenic GPR30 signaling as a functionally important component of the tumor microenvironment.

Estriol acts as a GPR30 antagonist in estrogen receptor-negative breast cancer cells

Estrogens are structurally related steroids that regulate important physiological processes. 17beta-estradiol (E2) is reversibly oxidized to estrone (E1) and both E2 and E1 can be irreversibly converted to estriol (E3), which also originates directly from androstenedione. The action of E2 has been traditionally explained by the binding to the estrogen receptor (ER) alpha and ER beta, however the G protein-coupled receptor (GPR) 30 has been recently involved in the rapid signaling triggered by estrogens. Although the role of E2 in the development of breast cancer has been largely documented, the contribution of E3 still remains to be completely evaluated. Here, we demonstrate for the first time that E3 acts as a GPR30 antagonist since it was able to inhibit the GPR30-mediated responses such as the rapid ERK activation, the up-regulation of target genes like c-fos and connective tissue growth factor, the proliferative effects observed in ER-negative SkBr3 cells.

Less Smad2 is good for you! A scientific update on coffee's liver benefits

Scientists at the National Institutes of Health have reported that increased coffee consumption is associated with a slower progression of fibrogenesis in patients with chronic and particularly alcoholic liver disease and a reduced incidence of heptocellular carcinoma. However, a causal mechanistic explanation was pending. New results indicate that the methylxanthine caffeine--a major component of coffee and the most widely consumed pharmacologically active substance in the world--might be responsible for this phenomenon, because it inhibits the synthesis of connective tissue growth factor (CTGF/CCN2) in liver parenchymal and nonparenchymal cells, primarily by inducing degradation of Smad2 (and to a much lesser extent Smad3) and thus impairment of transforming growth factor beta (TGF-beta) signaling. CTGF and TGF-beta play crucial roles in the fibrotic remodeling of various organs, and, ultimately, carcinogenesis. This article summarizes the clinical-epidemiological observations as well as the pathophysiological background and provides suggestions for the therapeutic use of (methyl)xanthine derivatives in the management of fibro-/carcinogenic (liver) diseases.

About coffee, cappuccino and connective tissue growth factor-Or how to protect your liver!?

Several epidemiological studies suggest that coffee drinking is inversely correlated with the risk of development of liver fibrosis. However, a causal, mechanistic explanation has long been pending. New results indicate that the methylxanthine caffeine, major component of coffee and the most widely consumed pharmacologically active substance in the world, might be responsible for this phenomenon as it, and even more potently its derived primary metabolite paraxanthine, inhibits transforming growth factor (TGF)-β-dependent and -independent synthesis of connective tissue growth factor (CTGF/CCN2) in liver parenchymal cells in vitro and in vivo. CTGF plays a crucial role in the fibrotic remodeling of various organs which has therefore frequently been proposed as therapeutic target in the management of fibrotic disorders. This article summarizes the clinical-epidemiological observations as well as the pathophysiological background of the antifibrotic effects of coffee consumption and provides suggestions for the therapeutic use of caffeine and its derived metabolic methylxanthines as potentially powerful drugs in patients with chronic fibrogenic liver disease by their inhibitory effect on (hepatocellular) CTGF synthesis.

Elevated concentrations of 15-deoxy-Delta12,14-prostaglandin J2 in chronic liver disease propose therapeutic trials with peroxisome proliferator activated receptor gamma-inducing drugs

BACKGROUND/AIMS

Current knowledge confers a crucial role to connective tissue growth factor (CTGF/CCN2) in hepatic fibrogenesis. Hepatocytes are likely to be the major cellular source of CTGF in the liver in which CTGF is sensitively upregulated by TGF-beta. Recently, we demonstrated that the methylxanthine derivate caffeine leads to an upregulation of peroxisome proliferator activated receptor gamma (PPARgamma) expression in hepatocytes, thus sensitizing these cells to the well-known inhibitory effect of 15-deoxy-Delta(12,14)-prostaglandin J(2) (15-d-PGJ(2)) on CTGF expression. However, upregulation of the receptor alone is not sufficient per se; its physiological ligand 15-d-PGJ(2) is required to exert an inhibitory effect on transforming growth factor-beta (TGF-beta) target genes such as CTGF.

METHODS

This study compared serum concentrations of 15-d-PGJ(2) in Caucasian patients with fibrotic liver diseases (n=289), Caucasian controls (n=136) and Caucasian non-liver disease (NLD) sick (n=307), as well as of Chinese patients with hepatocellular carcinoma (HCC) (n=43) and Chinese healthy controls (n=63) in order to characterize their suitability for therapeutic approaches with PPARgamma-inducing (i.e. CTGF inhibitory) drugs such as caffeine.

RESULTS

The presented data showed that Caucasian patients with ongoing hepatic fibrogenesis (mean 6.2+/-5.9 microg/L) displayed strikingly higher serum concentrations of 15-d-PGJ(2) than healthy probands (mean 2.3+/-1.0) and Caucasian patients with NLD (mean 2.7+/-1.4 microg/L). Similar results were found in Chinese patients with fully developed HCC (mean 1.3+/-0.7 microg/L) compared with Chinese healthy controls (mean 0.4+/-0.2 microg/L).

CONCLUSIONS

In conclusion, our data thus proposed an increased suitability of these patient groups for therapeutic approaches with drugs inducing PPARgamma expression, such as methylxanthine derivates.

Estrogenic GPR30 signalling induces proliferation and migration of breast cancer cells through CTGF

The steroid hormone oestrogen can signal through several receptors and pathways. Although the transcriptional responses mediated by the nuclear oestrogen receptors (ER) have been extensively characterized, the changes in gene expression elicited by signalling through the membrane-associated ER GPR30 have not been studied. We show here for ER-negative human breast cancer cells that the activation of GPR30 signalling by oestrogen or by hydroxytamoxifen (OHT), an ER antagonist but GPR30 agonist, induces a transcription factor network, which resembles that induced by serum in fibroblasts. The most strongly induced gene, CTGF, appears to be a target of these transcription factors. We found that the secreted factor connective tissue growth factor (CTGF) not only contributes to promote proliferation but also mediates the GPR30-induced stimulation of cell migration. These results provide a framework for understanding the physiological and pathological functions of GPR30. As the activation of GPR30 by OHT also induces CTGF in fibroblasts from breast tumour biopsies, these pathways may be involved in promoting aggressive behaviour of breast tumours in response to endogenous oestrogens or to OHT being used for endocrine therapy.