Clinicopathological significance of MMP-2 and its specific inhibitor TIMP-2 in gastric cancer

Study of the Relationship between MMP-2 and MMP-9 and Her2/neu Overexpression in Gastric Cancer: Clinico- Pathological Correlations

Background:

The relationship between the expressions of matrix metalloproteinases with clinico-pathological data on gastric cancer has been investigated in many countries, but this relationship remains unexplored in Iranian patients. Also, the correlation of the MMPs and the HER-2/neu proto-oncogene with other clinic-pathological variables has been evaluated for several other malignancies, but little effort has been made to shed light on the relationship with gastric cancer.

Methods:

We investigated MMP-2 and MMP-9 expression and HERE-2/neu overexpression in 48 gastric cancer patients referred to Afzalipour Hospital, associated with Kerman Medical University. Immunohistochemistry staining with rabbit polyclonal antibodies was used. Data statistical analysis was done by SPSS software (Version 20.0).

Results:

The mean age was 59, most of the patients were male (79.2%), and the average tumor size was larger than 5 centimeters in its greatest diameter. The majority of tumors were of the intestinal subtype and were located in the pyloric and antrum regions (43.8%). Invasion to muscularis properia was seen in 87.5% of the tumors (T3). MMP-2 and MMP-9 were highly expressed in 58.3% and 50% of cases, respectively, and Her-2/neu positivity was 10.4%. MMP-2, MMP-9 and HER-2 were found to have no relation with any clinicopathological parameters.

Conclusion:

According to the results of this study, MMP-2 and MMP-9 were highly expressed in gastric cancer, but there was no significant association with other clinicopathological variables.

Global transcriptomic analysis identifies SERPINE1 as a prognostic biomarker associated with epithelial-to-mesenchymal transition in gastric cancer

Background

The plasminogen activation system plays a pivotal role in regulating tumorigenesis. In this work, we aim to identify key regulators of plasminogen activation associated with tumorigenesis and explore potential mechanisms in gastric cancer (GC).

Methods

Gene profiling datasets were extracted from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were screened for and obtained by the GEO2R tool. The Database for Annotation, Visualization and Integrated Discovery was used for GO and KEGG enrichment analysis. Gene set enrichment analysis (GSEA) was performed to verify molecular signatures and pathways among The Cancer Genome Atlas or GEO datasets. Correlations between SERPINE1 and markers of epithelial-to-mesenchymal transition (EMT) were analyzed using the GEPIA database and quantitative real-time PCR (qRT-PCR). Interactive networks of selected genes were built by STRING and Cytoscape software. Finally, selected genes were verified with the Kaplan–Meier (KM) plotter database.

Results

A total of 104 overlapped upregulated and 61 downregulated DEGs were obtained. Multiple GO and KEGG terms associated with the extracellular matrix were enriched among the DEGs. SERPINE1 was identified as the only regulator of angiogenesis and the plasminogen activator system among the DEGs. A high level of SERPINE1 was associated with a poor prognosis in GC. GSEA analysis showed a strong correlation between SERPINE1 and EMT, which was also confirmed with the GEPIA database and qRT-PCR validation. FN1, TIMP1, MMP2, and SPARC were correlated with SERPINE1.The KM plotter database showed that an overexpression of these genes correlated with a shorter survival time in GC patients.

Conclusions

In conclusion, SERPINE1 is a potent biomarker associated with EMT and a poor prognosis in GC. Furthermore, FN1, TIMP1, MMP2, and SPARC are correlated with SERPINE1 and may serve as therapeutic targets in reversing EMT in GC.

Combinatorial engineering of N-TIMP2 variants that selectively inhibit MMP9 and MMP14 function in the cell

Developing selective inhibitors for proteolytic enzymes that share high sequence homology and structural similarity is important for achieving high target affinity and functional specificity. Here, we used a combination of yeast surface display and dual-color selective library screening to obtain selective inhibitors for each of the matrix metalloproteinases (MMPs) MMP14 and MMP9 by modifying the non-specific N-terminal domain of the tissue inhibitor of metalloproteinase-2 (N-TIMP2). We generated inhibitor variants with 30- to 1175-fold improved specificity to each of the proteases, respectively, relative to wild type N-TIMP2. These biochemical results accurately predicted the selectivity and specificity obtained in cell-based assays. In U87MG cells, the activation of MMP2 by MMP14 was inhibited by MMP14-selective blockers but not MMP9-specific inhibitors. Target specificity was also demonstrated in MCF-7 cells stably expressing either MMP14 or MMP9, with only the MMP14-specific inhibitors preventing the mobility of MMP14-expressing cells. Similarly, the mobility of MMP9-expressing cells was inhibited by the MMP9-specific inhibitors, yet was not altered by the MMP14-specific inhibitors. The strategy developed in this study for improving the specificity of an otherwise broad-spectrum inhibitor will likely enhance our understanding of the basis for target specificity of inhibitors to proteolytic enzymes, in general, and to MMPs, in particular. We, moreover, envision that this study could serve as a platform for the development of next-generation, target-specific therapeutic agents. Finally, our methodology can be extended to other classes of proteolytic enzymes and other important target proteins.

TIMP2 is a Poor Prognostic Factor and Predicts Metastatic Biological Behavior in Gastric Cancer

To explore the prognostic related factors and mechanisms of gastric cancer (GC), we performed the systematic analysis with integrated bioinformatics tools based on multiple on-line datasets. With uni-variate COX analysis, we screened out 37 survival hazardous genes in GC. Further GO assays disclosed that the signatures related with extracellular matrix and structure, and the functions of "cell adhesion molecule binding" and "integrin binding" were the vital mechanisms of disease progression, and tissue inhibitor of metalloproteinase-2 (TIMP2) was the potential biomarker for prognosis. Based on GSEA, GSVA and GCN, TIMP2 was demonstrated to interact with multiple integrin pathways and involve in the regulation of EMT, cell adhesion, and angiogenesis of GC. The associations of TIMP2 expression with reduced OS and RFS of patients were declared by Kaplan-Meier analysis, and further confirmed by 1000 internal bootstrap replications and external KM plotter analysis. With multi-variate COX regression and time-dependent ROC analysis, we validated the prediction independency and capacity of TIMP2 for prognosis. The relationships of TIMP2 with clinicopathological characteristics were also uncovered. Taken together, our findings identify TIMP2 as the novel candidate biomarker for poorer outcome of GC patients, and revealed the underlying functions of TIMP2 and the potential mechanisms for GC progression.

Role of SDF-1α/CXCR4 signaling pathway in clinicopathological features and prognosis of patients with nasopharyngeal carcinoma

The present study aims to explore the role of stromal cell-derived factor-1α (SDF-1α)/stromal cell-derived factor receptor-4 (CXCR4) signaling pathway to the clinicopathological features and prognosis of patients with nasopharyngeal carcinoma (NPC). From January 2009 to December 2010, 102 patients with NPC and 80 patients with chronic nasopharyngitis were enrolled for the study. Immunohistochemical staining, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting were employed to determine the expressions of SDF-1α and CXCR4 proteins in NPC tissues and chronic nasopharyngitis tissues. Chi-square test was conducted to analyze the associations of the expressions of SDF-1α and CXCR4 proteins with the clinicopathological features of NPC patients. Spearman rank correlation analysis was used to analyze the correlation between the SDF-1α protein expression and CXCR4 protein expression. The mRNA and protein expressions of SDF-1α and CXCR4 in NPC tissues were significantly higher than those in chronic nasopharyngitis tissues. The expressions of SDF-1α and CXCR4 proteins showed associations with T staging, N staging, tumor node metastasis (TNM) staging, skull base invasion, and cervical lymph node metastasis of NPC patients. Compared with NPC patients showing negative expressions of SDF-1α and CXCR4 proteins, those with positive expressions of SDF-1α and CXCR4 proteins had a significantly shorter survival time. SDF-1α protein, CXCR4 protein, EBV-IgG status, T staging, N staging, TNM staging, skull base invasion, and cervical lymph node metastasis were independent risk factors for the prognosis of NPC. The findings indicated that SDF-1α/CXCR4 signaling pathway might be associated with the clinicopathological features and prognosis of patients with NPC.

Association of TIMP-2-418G/C and TIMP-2-303G/A with gastric cancer: a meta-analysis

Background

According to the relevant reports, TIMP-2 polymorphism might be associated with the susceptibility to gastric cancer. Owing to the inconclusive results from the published studies based on the association between TIMP-2 single nucleotide polymorphisms (SNPs) and gastric cancer susceptibility, a meta-analysis was conducted to investigate the correlation between the TIMP-2 SNPs and the risk of gastric cancer.

Materials and methods

PubMed, Embase, CNKI and Wanfang databases were systematically searched to cover all the studies based on the association of two SNPs with the susceptibility to gastric cancer published before April 2016. Pooled odds ratios (ORs) and 95% confidence intervals were calculated for all genetic models.

Results

A total of six case–control studies on TIMP-2-418G/C and four studies on TIMP-2-303G/A were included. No obvious association was found between TIMP-2-418G/C polymorphism and the risk of gastric cancer in all the genetic models. On the other hand, TIMP-2-303G/A polymorphism had a significant association with increased risk of gastric cancer in homozygote recessive and allele comparisons, and similar results were observed in subgroups of Asian populations, but there were inadequate data to completely verify the association between TIMP-2-303G/A and gastric cancer.

Conclusion

TIMP-2-418G/C polymorphism is not correlated with the risk of gastric cancer, while TIMP-2-303G/A is a risk factor for gastric cancer, especially in Asian populations. However, owing to the limited cases, the results of TIMP-2-303G/A should be thoroughly examined and validated with large-scale and well-designed studies.

The Impact of MMP-2 and Its Specific Inhibitor TIMP-2 Expression on the WHO Grade and Prognosis of Gliomas in Chinese Population: a Meta-Analysis

So far, the prognostic value of matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of matrix metalloproteinase 2 (TIMP-2) expressions in patients with gliomas has been widely reported, especially in China. But, the results were inconsistent. Thus, we conducted a meta-analysis to determine the correlation of MMP-2 and TIMP-2 expressions with the prognosis of patients with gliomas. Identical search strategies were used to search relevant literature in electronic databases updated to May 1, 2015, and odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were estimated. Funnel plots and Egger’s tests were conducted for the evaluation of publication bias, and heterogeneity and sensitivity were also analyzed. Finally, a total of 25 studies involving 1572 patients were included in the meta-analysis. Coincidentally, all these studies were conducted in Chinese population. It was found that MMP-2 expression was significantly associated with high-WHO grade gliomas (n = 24, OR = 6.54, CI = 4.98–8.60; I² = 0 %, P = 0.911) and poor overall survival (OS), while it did not correlate to age (n = 2, OR = 0.78, CI = 0.35–1.74; I² = 0 %, P = 0.621) and gender (n = 2, OR = 1.15, CI = 0.51–2.62; I² = 0 %, P = 0.995). Moreover, the results of the pooled analysis indicated that there was no association between TIMP-2 expression and the WHO grade of gliomas (n = 7, OR = 1.02, 95 % CI = 0.68–1.54; I² = 71.4 %, P = 0.002), but the ratio of MMP-2 and TIMP-2 (MMP-2/TIMP-2) rose with the increase of the WHO grade of gliomas. In conclusion, there was no correlation between TIMP-2 expression and the WHO grade of gliomas, while MMP-2 expression was potently associated with high-WHO grade of gliomas.

Metformin inhibits the proliferation, metastasis, and cancer stem-like sphere formation in osteosarcoma MG63 cells in vitro

Metformin is an oral drug that has been widely used to treat type 2 diabetes mellitus. Interestingly, accumulated evidence indicate that metformin may reduce the risk of cancer in patients with type 2 diabetes and inhibit tumor cell growth and survival in numerous malignancies, including osteosarcoma (OS) cells. In the present study, we aimed to investigate the effects of metformin on the proliferation, migration, invasion, and sphere formation in OS MG63 cells in vitro. Metformin suppressed OS MG63 cell proliferation in a dose- and time-dependent manner and markedly blocked anti-metastatic potentials, migration, and invasion, by downregulating matrix metalloproteinase 2 (MMP2) and MMP9. Besides, we established OS cancer stem-like cell (CSC) model with sarcosphere formation assay and demonstrated that metformin posed damage on CSCs in OS by inhibiting sphere formation and by inducing their stemness loss. The stemness of CSCs in OS such as self-renewal and differentiation potentials was both impaired with a significant decrease of Oct-4 and Nanog activation. Consistent with this, the positive rates of CD90, CD133, and stage-specific embryonic antigen-4 (SSEA-4) were all observed with reductions in response to metformin exposure. In addition, Western blot showed that metformin activated AMPKα at Tyr172, followed by a downregulated phosphorylation of mammalian target of rapamycin (mTOR)/S6 and feedback activation of p-AKT Ser(473) in both OS MG63 cells and CSCs. This indicates that AMPK/mTOR/S6 signaling pathway might be involved in the growth inhibition of both OS MG63 cells and CSCs. These results suggest that metformin, a potential anti-neoplastic agent, might make it a novel therapeutic choice for the treatment of OS in the future.

Relationship between single-nucleotide polymorphism of matrix metalloproteinase-2 gene and colorectal cancer and gastric cancer susceptibility: a meta-analysis

Background

Recently, the published data on the association between matrix metalloproteinase-2 (MMP-2) (C-1306T) polymorphism and colorectal cancer (CRC) and gastric cancer (GC) (gastrointestinal cancer) risk remained controversial. The aim of this study is to investigate the relationship between the risk of CRC and GC and single-nucleotide polymorphism of MMP-2(C-1306T).

Methods

Medline, Embase, Science Citation Index, and PubMed were thoroughly searched to identify relevant studies. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association.

Results

We performed a meta-analysis of 14 studies including 642 cases and 692 controls for CRC and 1,936 cases and 3,490 controls for GC. The result indicates that there is significant relationship between MMP-2(C-1306T) polymorphism and CRC risk in recessive model and codominant model (TT vs CC/CT: OR: 2.39, 95% CI: 1.30–4.37, P=0.005; TT vs CC: OR: 2.36, 95% CI: 1.29–4.34, P=0.006). In subgroup analysis according to ethnicity, significant associations were found in Caucasians (TT vs CC/CT: OR: 2.87, 95% CI: 1.43–5.78, P=0.003; TT vs CC: OR: 2.86, 95% CI: 1.41–5.80, P=0.003), but we did not find significant evidence with GC in all genetic models, and in stratified analysis according to ethnicity, no significant risk was found in the subgroup too.

Conclusion

This meta-analysis considered that the MMP-2(C-1306T) polymorphism is a risk factor for CRC susceptibility, especially in Caucasians, but it does not support any relationship to GC, and further studies are needed to explore the association.

Expression levels of matrix metalloproteinase-9 in human gastric carcinoma

The present report investigated the correlation between the expression levels of matrix metalloproteinase (MMP)-9 in gastric carcinoma patients and the clinicopathological characteristics. Forty-five samples of gastric carcinoma and distal gastric mucosa tissue, and 10 samples of healthy gastric mucosa tissue were analyzed using semi-quantitative polymerase chain reaction, as well as immunohistochemical and hematoxylin and eosin staining. MMP-9 protein levels in serum samples from the same patients were quantified by enzyme-linked immunosorbent assay. The present report identified that MMP-9 expression was markedly higher in the gastric carcinoma tissue (86.67%) than in the adjacent healthy tissue (10.00%). A positive association was identified between the level of MMP-9 protein expression and the depth of cancer invasion (P<0.05). Furthermore, the preoperative serum levels of the MMP-9 protein in the gastric carcinoma tissue were correlated with the tumor-node-metastasis stage and occurrence of lymph node metastasis (P<0.01). Data from the present report indicates that MMP-9 may be key in gastric carcinoma malignancy, and implies that MMP-9 may serve as a novel biomarker in the diagnosis and prognosis of gastric carcinoma.

Deregulation of the cell polarity protein Lethal giant larvae 2 (Lgl2) correlates with gastric cancer progression

BACKGROUND

We investigated the roles of Lethal giant larvae 2 (Lgl2), an epithelial cell polarity protein, during gastric carcinogenesis and gastric cancer (GC) progression and evaluated the correlation of Lgl2 with epithelial-mesenchymal transition (EMT) markers.

METHODS

Lgl2 protein and mRNA expression were determined by immunohistochemistry and mRNA in situ hybridization in a large series of GC and preneoplastic lesions. Additionally, expression of 7 EMT markers was examined by immunohistochemistry.

RESULTS

Loss of membrane Lgl2 staining in GC was observed in 347 of 409 GCs. Lgl2 loss was associated with diffuse histological type (P < 0.001), advanced stage (P = 0.021), and worse prognosis (P = 0.047). Furthermore, Lgl2 loss correlated with reduced E-cadherin expression (P < 0.01) and increased expression of vimentin (P < 0.01). Combined analysis of Lgl2 and the EMT markers, S100A4 and MMP2, improved predictions of patient outcomes. During gastric carcinogenesis, membrane expression of Lgl2 was progressively lost in 4 % of normal mucosa, 75 % of intestinal metaplasia, 58 % of gastric dysplasia, 69 % of intestinal type GC, and 96 % of diffuse type GC.

CONCLUSIONS

Our results suggest that Lgl2 loss occurs at an early stage of gastric carcinogenesis and contributes to GC progression.

No correlation between TIMP2 -418 G>C polymorphism and increased risk of cancer: evidence from a meta-analysis

Aim

Tissue inhibitor of metalloproteinase (TIMP2) is involved in the regulation of matrix metalloproteinase 2 (MMP2) and shown to implicate in cancer development and progression. The results from the published studies based on the association between TIMP2 -418 G>C polymorphism and cancer risk are inconsistent. In this meta-analysis, we aimed to evaluate the potential association between TIMP2 -418 G>C polymorphism and cancer risk.

Methodology

We searched PubMed (Medline) and EMBASE web databases to cover all studies based on relationship of TIMP2 -418 G>C polymorphism and risk of cancer until October 2013. The meta-analysis was performed for selected case-control studies and pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for all genetic models.

Results

A total of 2225 cancer cases and 2532 controls were included from ten eligible case-control studies. Results from overall pooled analysis suggested no evidence of significant risk between TIMP2 -418 G>C polymorphism and cancer risk in any of the genetic models, such as, allele (C vs. G: OR = 1.293, 95% CI = 0.882 to 1.894, p = 0.188), homozygous (CC vs. GG: OR = 0.940, 95% CI = 0.434 to 2.039, p = 0.876), heterozygous (GC vs. GG: OR = 1.397, 95% CI = 0.888 to 2.198, p = 0.148), dominant (CC+GC vs. GG: OR = 1.387, 95% CI = 0.880 to 2.187, p = 0.159) and recessive (CC vs. GG+GC: OR = 0.901, 95% CI = 0.442 to 1.838, p = 0.774) models. No evidence of publication bias was detected during the analysis.

Conclusions

The present meta-analysis suggests that the TIMP2 -418 G>C polymorphism may not be involved in predisposing risk factor for cancer in overall population. However, future larger studies with group of populations are needed to analyze the possible correlation.

Combination of strong MMP-2 and weak TIMP-2 immunostainings is a significant prognostic factor in endometrial carcinoma

Objective. The aim of this study was to evaluate the combined effects of MMP-2 and TIMP-2 protein immunoreactivities on the prognosis in endometrial carcinoma. Methods. Paraffin-embedded tissue samples from 225 primary endometrioid adenocarcinomas and 13 histologies other than endometrioid adenocarcinoma were immunohistochemically stained for MMP-2 and TIMP-2. Results. In Kaplan-Meier analysis, the 5-year cancer-specific survival rate of the endometrioid adenocarcinoma patients with negative MMP-2 and positive TIMP-2 staining was 100%, whereas only 78% of patients presenting with positive MMP-2 and negative TIMP-2 staining results were alive at that time. In Cox regression analysis, patients with positive MMP-2 and negative TIMP-2 immunostaining had a 4.7-fold relative risk of death from endometrial carcinoma compared to the group of patients with negative MMP-2 and positive or negative TIMP-2 immunoreaction. Conclusions. MMP-2 seems to be the main metalloproteinase determining the prognosis in endometrial carcinoma. Combination of strong MMP-2 and weak TIMP-2 immunostainings was the most potent prognostic marker for poor survival.

Molecular mechanisms of tissue inhibitor of metalloproteinase 2 in the tumor microenvironment

There has been a recent paradigm shift in the way we target cancer, drawing a greater focus on the role of the tumor microenvironment (TME) in cancer development, progression and metastasis. Within the TME, there is a crosstalk in signaling and communication between the malignant cells and the surrounding extracellular matrix. Matrix metalloproteinases (MMPs) are zinc-dependent endoproteases that have the ability to degrade the matrix surrounding a tumor and mediate tumor growth, angiogenesis and metastatic disease. Their endogenous inhibitors, the Tissue Inhibitors of Metalloproteinases (TIMPs), primarily function to prevent degradation of the ECM via inhibition of MMPs. However, recent studies demonstrate that TIMP family members also possess MMP-independent functions. One TIMP member in particular, TIMP-2, has many distinct properties and functions, that occur independent of MMP inhibition, including the inhibition of tumor growth and reduction of angiogenesis through decreased endothelial cell proliferation and migration. The MMP-independent molecular mechanisms and signaling pathways elicited by TIMP-2 in the TME are described in this review.

Immunoexpression of metalloproteinases 2 and 14 and TIMP-2 inhibitor in main types of primary gastric carcinomas and lymph node metastasis

Metalloproteinase-2 (MMP-2) and -14 (MMP-14) and the tissue inhibitor of metalloproteinases type 2 (TIMP-2) participate in epithelial-mesenchymal transition and tumor progression in many cancers. However, the correlation between these enzymes in gastric cancer and the metastatic potential to their respective lymph node needs to be determined. Here, we evaluated the expression of these enzymes in gastric carcinoma and lymph node metastases and their possible involvement in tumor progression. Histological samples from 83 patients with gastric cancer and their respective lymph nodes were used. MMP-2, MMP-14 and TIMP-2 immunoexpression was scored. TIMP-2 expression in tumor-associated macrophages occurred more frequently than in normal mucosa (P = 0.0128). Female tumor samples presented higher MMP-2 expression (P = 0.0248), while TIMP-2 occurred mainly in patients over 50 years old (P = 0.0034). MMP-2 was higher expressed in primary tumor macrophages than in neoplastic cells (P = 0.0118), and was also seen in macrophages from metastatic-affected lymph nodes of intestinal and diffuse histotypes (P = 0.0006). MMP-2, MMP-14 and TIMP-2 expression in mononuclear cells might be correlated with progression of gastric cancer. MMP-14 production by macrophages appears to be more involved in diffuse gastric cancer progression.

The prognostic role of matrix metalloproteinase 2 in gastric cancer: a systematic review with meta-analysis

PURPOSE

The prognostic role of matrix metalloproteinase 2 (MMP-2) in gastric cancer remains controversial. We systematically reviewed the evidence for assessment of MMP-2 expression in gastric cancer to elucidate this issue.

METHOD

Pubmed, Embase and Web of Science were searched to identify eligible studies to evaluate the association of MMP-2 expression and overall survival and clinicopathological features of gastric cancer.

RESULTS

MMP-2 overexpression was significantly correlated with poor OS of gastric cancer patients (HR 1.92, 95 % CI 1.48-2.48). Subgroup analysis indicated that MMP-2 overexpression had an unfavorable impact on OS in Asian countries (HR 2.23, 95 % CI 1.57-3.17) and European countries (HR 1.43, 95 % CI 1.13-1.80). Furthermore, MMP-2 overexpression was significantly associated with TNM stage (TIII/TIV vs TI/TII: OR 2.17, 95 % CI 1.64-2.87), the depth of invasion (T3/T4 vs T1/T2: OR 2.59, 95 % CI 1.63-4.12), lymph node metastasis (positive vs negative: OR 2.21, 95 % CI 1.69-2.88), and distant metastasis (positive vs negative: OR 4.44, 95 % CI 1.24-15.94).

CONCLUSION

This meta-analysis indicated that MMP-2 overexpression might be a predictive factor for poor prognosis for gastric cancer.

Leucine-rich repeat-containing G-protein-coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer

Background:

Leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5), which is identified as a novel intestinal stem cell marker, is overexpressed in various tumours. In this study, we explore Lgr5 expression in gastric carcinoma and analyse its role in invasion, metastasis, and prognosis in carcinoma.

Methods:

A combination of immunohistochemistry, western blotting, and quantitative reverse transcription–polymerase chain reaction were used to detect mRNA and protein expression levels of Lgr5 and matrix metalloproteinase 2 (MMP2). Small interfering RNA against Lgr5 was designed, synthesised, and transfected into AGS cells. The effects of Lgr5 siRNA on cell invasion were detected by transwell invasion chamber assay and wound healing assay.

Results:

Leucine-rich repeat-containing G-protein-coupled receptor 5 expression was significantly higher in gastric carcinomas than in normal mucosa. Leucine-rich repeat-containing G-protein-coupled receptor 5 expression positively correlated with the depth of invasion, lymph node metastasis, distance of metastasis, and MMP2 expression levels. Multivariate analysis showed that Lgr5 had an independent effect on survival, and that it positively correlated with MMP2. Leucine-rich repeat-containing G-protein-coupled receptor 5 siRNAs inhibited Lgr5 mRNA and protein expression. Transwell assays indicated that these siRNAs resulted in significantly fewer cells migrating through the polycarbonate membrane, and wound healing assay also indicated that siRNAs decreased the migration of cells. Inhibition of Lgr5 resulted in a significant decrease in MMP2 and β-catenin levels compared with those in controls.

Conclusions:

Leucine-rich repeat-containing G-protein-coupled receptor 5 was correlated with invasion and metastasis. Leucine-rich repeat-containing G-protein-coupled receptor 5 inhibition could serve as a novel therapeutic approach.

Expression of the matrix metalloproteases 2, 14, 24, and 25 and tissue inhibitor 3 as potential molecular markers in advanced human gastric cancer

Background. During progression of gastric cancer (GC), degradation of the extracellular matrix is mediated by the matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs): changes in the expression of these have been related to unfavorable prognosis in GC. Objective. To analyze the expression of certain MMPs and TIMPs in chronic superficial gastritis (SG) and GC. Methods. The expression of MMPs and TIMPs was determined using qRT-PCR; the expression was classified, using threshold cycle (C_T) values, as very high (C_T ≤ 25), high (C_T = 26–30), moderate (C_T = 31–35), low (C_T = 36–39), or not detected (C_T = 40). Strength of association was estimated between the proteins, which were detected by Western blot, and the risk of developing GC. Results. We found a high expression of MMP1, MMP2, MMP14, TIMP1, and TIMP3; moderate one of MMP9 and MMP25, and low one of MMP13 and MMP24 in both tissues. In absolute mRNA levels, significant differences were found in expression of MMP2, MMP24, and MMP25, which are overexpressed in GC compared with SG. The presence of the proteins MMP-14 and TIMP-3 was associated with the risk of developing GC. Conclusions. We consider that MMP2, MMP24, and MMP25 and the proteins MMP-14 and TIMP-3 could be candidates for prognostic molecular markers in GC.

Analysis of the MMP-dependent and independent functions of tissue inhibitor of metalloproteinase-2 on the invasiveness of breast cancer cells

Matrix metalloproteinases (MMPs) are secreted endopeptidases that play an essential role in remodeling the extracellular matrix (ECM). MMPs are primarily active during development, when the majority of ECM remodeling events occurs. In adults, elevated MMP activity has been observed in many pathological conditions such as cancer and osteoarthritis. The proteolytic activity of MMPs is controlled by their natural inhibitors - the tissue inhibitor of metalloproteinases (TIMPs). In addition to blocking MMP-mediated proteolysis, TIMPs have a number of MMP-independent functions including binding to cell surface proteins thereby stimulating signaling cascades. TIMP-2, the most studied member of the family, can both inhibit and activate MMPs directly, as well as inhibit MMP activity indirectly by upregulating expression of RECK, a membrane anchored MMP regulator. While TIMP-2 has been shown to play important roles in breast cancer, we describe how the MMP-independent effects of TIMP-2 can modulate the invasiveness of MCF-7, T47D and MDA-MB-231 breast cancer cells. Using an ALA + TIMP-2 mutant which is devoid of MMP inhibition, but still capable of initiating specific cell signaling cascades, we show that TIMP-2 can differentially affect MMP activity and cellular invasiveness in both an MMP dependent and independent manner. More specifically, MMP activity and invasiveness is increased with the addition of exogenous TIMP-2 in poorly invasive cell lines whereas it is decreased in highly invasive cells lines (MDA-MB-231). Conversely, the addition of ALA + TIMP-2 resulted in decreased invasiveness regardless of cell line.

Aquaporin-3 positively regulates matrix metalloproteinases via PI3K/AKT signal pathway in human gastric carcinoma SGC7901 cells

BACKGROUND

matrix metalloproteinases (MMPs) are produced by tumor cells, so they may be associated with tumor progression including invasion, migration, angiogenesis and metastasis. Aquaporin-3 (AQP3) also plays a critical role in gastric cancer cell migration and proliferation.

METHODS

In this study, AQP3 was silenced or over-expressed in SGC7901 cells.

RESULTS

We found a significant decrease in MT1-MMP, MMP-2, and MMP-9 expression after AQP3 knockdown, and a significant increase in MT1-MMP, MMP-2, and MMP-9 expression after AQP3 over-expression in SGC7901 cells. We also found that AQP3 silence led to a significant decrease of phosphorylation of ser473 in AKT in SGC7901 cells.

CONCLUSION

Our findings showed that AQP3 might positively regulate MMPs proteins expression through PI3K/AKT signal pathway in human gastric carcinoma SGC7901 cells.

Clinical impact of MMP and TIMP gene polymorphisms in gastric cancer

BACKGROUND

Recent studies suggest that single-nucleotide polymorphisms (SNPs) within matrix metalloproteinase (MMP) genes and genes of tissue inhibitors of metalloproteinases (TIMPs) have an impact on the expression of these genes and on the prognosis for gastric cancer.

METHODS

Genomic DNA was extracted from paraffin-embedded tissues of 135 patients who were treated surgically for primary gastric carcinoma. Genotyping was performed for MMP-2(-1306C>T), TIMP-2(303C>T), and MMP-7(-181A>G). MMP-2 and TIMP-2 antigen expression in resected tumor tissues was detected immunohistochemically. Genotyping was correlated with antigen expression, histopathologic parameters, and prognosis.

RESULTS

The SNPs did not correlate with tumor differentiation, pT, R category, or the classifications according to the International Union Against Cancer (UICC), the World Health Organization (WHO), and Laurén and Ming. A significant correlation was observed for TIMP-2(303C>T) with higher pN stages (p = 0.01) and more distant metastasis (p = 0.02) for patients with the CC genotypes. In univariate analysis, patients with the TIMP-2(303C>T) CC genotype had an inferior survival, that was not significant (p = 0.2). However, among the gastric cancer patients in the present study, MMP-2(-1306C>T) significantly correlated with gender, with men having more CC genotypes than women (p = 0.025). There were no significant correlations between genotype and protein levels of MMP-2 (p = 0.766) and TIMP-2 (p = 0.684).

CONCLUSIONS

The TIMP-2(303C>T) CC genotype is associated with higher pN and pM categories and, in contrast to previous studies, with worse survival in gastric cancer.

Protocatechuic acid inhibits cancer cell metastasis involving the down-regulation of Ras/Akt/NF-κB pathway and MMP-2 production by targeting RhoB activation

BACKGROUND AND PURPOSE

Protocatechuic acid (PCA) is plentiful in edible fruits and vegetables and is thus one anti-oxidative component of normal human diets. However, the molecular mechanisms involved in the chemopreventive activity of PCA are poorly understood. Here, we investigated the mechanism(s) underlying the anti-metastatic potential of PCA.

EXPERIMENTAL APPROACH

We used AGS cells in a wound healing model and Boyden chamber assays in vitro and injection of B16/F10 melanoma cells in mice (metastasis model in vivo) to analyse the effect of PCA on cancer cell invasion and metastasis. The activities and expression of molecular proteins were measured by zymographic assay, real-time RT-PCR and Western blotting.

KEY RESULTS

PCA inhibited cell migration and invasion at non-cytotoxic concentrations. Decreased expression of matrix metalloproteinase (MMP)-2 and a coincident increase in tissue inhibitor of MMP followed treatment with PCA. The PCA-inhibited MMP-2 activity and expression was accompanied by inactivation of NF-κB. All these effects of PCA could be mediated via the RhoB/ protein kinase Cε (PKCε) and Ras/Akt cascade pathways, as demonstrated by inhibition of PKCε and transfection of PKCε siRNA and ras overexpression vector. Finally, PCA inhibited metastasis of B16/F10 melanoma cells to the liver in mice.

CONCLUSION AND IMPLICATIONS

Our data imply that PCA down-regulated the Ras/Akt/NF-κB pathway by targeting RhoB activation, which in turn led to a reduction of MMP-mediated cellular events in cancer cells and provides a new mechanism for the anti-cancer activity of PCA.

Downregulation of NDRG1 promotes invasion of human gastric cancer AGS cells through MMP-2

The N-myc downstream-regulated gene-1 (NDRG1) has recently been proposed as a metastasis suppressor, but its precise role remains unclear. To investigate whether NDRG1 can indeed influence the metastasis progress, expression of endogenous NDRG1 was knocked down in human AGS gastric adenocarcinoma cells using RNA interference. Stable NDRG1 "silenced" transfectants showed similar growth rates as their control counterparts. By contrast, invasive ability in Matrigel invasion activity and Gelatinolytic activity by matrix metalloproteinase-2 (MMP-2) were markedly increased in NDRG1 "silenced" cells. Moreover, re-expression of NDRG1 by recombinant adenovirus Ad-NDRG1 in NDRG1 "silenced" cells inhibited the increased invasive ability. Further study, we found the induction of MMP-2 by downregulation of NDRG1 was mediated by MT1-MMP. Altogether, our results imply that NDRG-1 could play a key role in the regulation of cellular invasion and metastasis, which may involve the upregulation of matrix metalloproteinases.

High expression of osteoglycin decreases gelatinase activity of murine hepatocarcinoma Hca-F cells

AIM: To investigate the possible correlation between osteoglycin expression and gelatinase activity of mouse hepatocarcinoma Hca-F cells.

METHODS: A eukaryotic expression plasmid pIRESpuro3 osteoglycin(+) was constructed and transfected into Hca-F cells to investigate the possible correlation between osteoglycin expression and gelatinase activity of Hca-F cells cultured with extract of lymph node, liver, spleen or in DMEM medium. The activity of gelatinases was examined through zymographic analysis.

RESULTS: High expression of osteoglycin attenuated the gelatinase activity of Hca-F cells cultured with extract of lymph node, and at the same time, decreased the metastatic potential of Hca-F cells to peripheral lymph nodes in vivo.

CONCLUSION: High expression of osteoglycin decreases the gelatinase activity of Hca-F cells cultured with extract of lymph node; regulation of gelatinase activity might be one of mechanisms that osteoglycin contributes to lymphatic metastasis suppression.