MMP28 (epilysin) as a novel promoter of invasion and metastasis in gastric cancer

Identification of novel therapeutic target and prognostic biomarker in matrix metalloproteinase gene family in pancreatic cancer

Matrix metalloproteinases (MMPs) play an essential role in various physiological events. Recent studies have revealed its carcinogenic effect in malignancies. However, the different expression patterns, prognostic value, and immunological value of MMPs in pancreatic ductal adenocarcinoma (PDAC) are yet to be comprehensively explored. We utilized Gene Expression Profiling Interactive Analysis (GEPIA) and Gene Expression Omnibus databases to explore the abnormal expression of MMPs in PDAC. Then, Kaplan-Meier survival curve and Cox regression analysis were performed to assess the prognostic value of MMPs. Association between MMPs expression and clinicopathological features was analyzed through UALCAN website. Functional annotations and GSEA analysis were performed to excavate the possible signaling pathways involving prognostic-related MMP. TIMER and TISCH database were used to performed immune infiltration analysis. The expression of prognostic-related MMP in pancreatic cancer cell lines and normal pancreatic cells was detected by Real time quantitative PCR. We observed that 10 MMP genes were consistently up-regulated in GEPIA and GSE62452 dataset. Among them, five highly expressed MMPs (MMP1, MMP3, MMP11, MMP14, MMP28) were closely related to poor clinical outcomes of PDAC patients. Cox regression analysis indicated MMP28 was a risk factor influencing the overall survival of patients. In the clinicopathological analysis, up-regulated MMP28 was significantly associated with higher tumor grade and the mutation status of TP53. GSEA analysis demonstrated that high expression of MMP28 was involved in "interferon_alpha_response" and "P53_pathway". Immune infiltration analysis showed that there was no correlation between MMP28 expression and immune cell infiltration. Single-cell sequencing analysis showed MMP28 has strong correlations with malignant cells and stromal cells infiltration in the tumor microenvironment. And MMP28 was highly expressed in various pancreatic cancer cell lines. In conclusion, MMP28 may represent a potential prognosis biomarker and novel therapeutic molecular targets for PDAC.

Matrix Metalloproteinases and Their Inhibitors in Pulmonary Fibrosis: EMMPRIN/CD147 Comes into Play

Pulmonary fibrosis (PF) is characterized by aberrant extracellular matrix (ECM) deposition, activation of fibroblasts to myofibroblasts and parenchymal disorganization, which have an impact on the biomechanical traits of the lung. In this context, the balance between matrix metalloproteinases (MMPs) and their tissue inhibitors of metalloproteinases (TIMPs) is lost. Interestingly, several MMPs are overexpressed during PF and exhibit a clear profibrotic role (MMP-2, -3, -8, -11, -12 and -28), but a few are antifibrotic (MMP-19), have both profibrotic and antifibrotic capacity (MMP7), or execute an unclear (MMP-1, -9, -10, -13, -14) or unknown function. TIMPs are also overexpressed in PF; hence, the modulation and function of MMPs and TIMP are more complex than expected. EMMPRIN/CD147 (also known as basigin) is a transmembrane glycoprotein from the immunoglobulin superfamily (IgSF) that was first described to induce MMP activity in fibroblasts. It also interacts with other molecules to execute non-related MMP aactions well-described in cancer progression, migration, and invasion. Emerging evidence strongly suggests that CD147 plays a key role in PF not only by MMP induction but also by stimulating fibroblast myofibroblast transition. In this review, we study the structure and function of MMPs, TIMPs and CD147 in PF and their complex crosstalk between them.

Upregulation of CD36, a Fatty Acid Translocase, Promotes Colorectal Cancer Metastasis by Increasing MMP28 and Decreasing E-Cadherin Expression

Altered fatty acid metabolism continues to be an attractive target for therapeutic intervention in cancer. We previously found that colorectal cancer (CRC) cells with a higher metastatic potential express a higher level of fatty acid translocase (CD36). However, the role of CD36 in CRC metastasis has not been studied. Here, we demonstrate that high expression of CD36 promotes invasion of CRC cells. Consistently, CD36 promoted lung metastasis in the tail vein model and GI metastasis in the cecum injection model. RNA-Seq analysis of CRC cells with altered expression of CD36 revealed an association between high expression of CD36 and upregulation of MMP28, a novel member of the metallopeptidase family of proteins. Using shRNA-mediated knockdown and overexpression of CD36, we confirmed that CD36 regulates MMP28 expression in CRC cells. siRNA-mediated knockdown of MMP28 decreases invasion of CRC cells, suggesting that MMP28 regulates the metastatic properties of cells downstream of CD36. Importantly, high expression of MMP28 leads to a significant decrease in active E-cadherin and an increase in the products of E-cadherin cleavage, CTF1 and CTF2. In summary, upregulation of CD36 expression promotes the metastatic properties of CRC via upregulation of MMP28 and an increase in E-cadherin cleavage, suggesting that targeting the CD36-MMP28 axis may be an effective therapeutic strategy for CRC metastasis.

CRISPR activation screen in mice identifies novel membrane proteins enhancing pulmonary metastatic colonisation

Melanoma represents ~5% of all cutaneous malignancies, yet accounts for the majority of skin cancer deaths due to its propensity to metastasise. To develop new therapies, novel target molecules must to be identified and the accessibility of cell surface proteins makes them attractive targets. Using CRISPR activation technology, we screened a library of guide RNAs targeting membrane protein-encoding genes to identify cell surface molecules whose upregulation enhances the metastatic pulmonary colonisation capabilities of tumour cells in vivo. We show that upregulated expression of the cell surface protein LRRN4CL led to increased pulmonary metastases in mice. Critically, LRRN4CL expression was elevated in melanoma patient samples, with high expression levels correlating with decreased survival. Collectively, our findings uncover an unappreciated role for LRRN4CL in the outcome of melanoma patients and identifies a potential therapeutic target and biomarker.

Elevated S100A9 expression in chronic rhinosinusitis coincides with elevated MMP production and proliferation in vitro

Chronic rhinosinusitis (CRS) is a common condition associated with inflammation and tissue remodeling of the nose and paranasal sinuses, frequently occurring with nasal polyps and allergies. Here we investigate inflammation and the protease profile in nasal tissues and plasma from control non-CRS patients and CRS patients. Gene expression for several cytokines, proteases, and antiproteases was quantified in nasal tissue from non-CRS and CRS subjects with nasal polyps. Elevated expression of S100A9, IL1A, MMP3, MMP7, MMP11, MMP25, MMP28, and CTSK was observed in tissue from CRS subjects with nasal polyps compared to control tissue. Tissue protein analysis confirmed elevated levels of these targets compared to controls, and increased MMP3 and MMP7 observed in CRS subjects with nasal polyps compared to CRS subjects without polyps. Plasma concentrations of MMP3 and MMP7 were elevated in the CRS groups compared to controls. The nasal cell line, CCL-30, was exposed to S100A9 protein, resulting in increased MMP3, MMP7, and CTSK gene expression and elevated proliferation. Silencing MMP3 significantly reduced S100A9-mediated cell proliferation. Therefore, the elevated expression of S100A9 and MMPs are observed in CRS nasal tissue and S100A9 stimulated MMP3 responses to contribute to elevated nasal cell proliferation.

Development and validation of a metastasis-related Gene Signature for predicting the Overall Survival in patients with Pancreatic Ductal Adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal, aggressive cancer characterized by invasiveness and metastasis. In this study, we aimed to propose a gene prediction model based on metastasis-related genes (MTGs) to more accurately predict PDAC prognosis.

Methods: Differentially expressed MTGs (DE-MTGs) were identified via integrated analysis of gene expression omnibus (GEO) datasets and Human Cancer Metastasis Database (HCMDB). Overall survival (OS) related DE-MTGs were then identified and a prognostic gene signature was established using Lasso-Cox regression with TCGA-PAAD datasets. Tumor immunity was analyzed using ESTIMATE and CIBERSORT algorithms. Finally, a nomogram predicting 1-year, 2-year, and 3-year OS of PDAC patients was established based on the prognostic gene signature and relevant clinical parameters using a stepwise Cox regression model.

Results: A total of 36 DE-MTGs related to OS were identified in PDAC. Consequently, an MTG-based gene signature comprising of RACGAP1, RARRES3, TPX2, MMP28, GPR87, KIF14, and TSPAN7 was established to predict the OS of PDAC. The MTG-based gene signature was able to distinguish high-risk patients with significantly poorer prognosis and accurately predict OS of PDAC in both the training and external validation datasets. Cox regression analysis indicated that the MTG-based gene signature was an independent prognostic factor in PDAC. The gene set enrichment analysis (GSEA) showed that molecular alterations in the high-risk group were associated with multiple oncological pathways. Moreover, analysis of tumor immunity revealed significantly higher levels of follicular helper T cells and M0 macrophage infiltration, and lower levels of infiltrating naïve B cells, CD8 T cells, monocytes, and resting dendritic cells in the high-risk group. Immune cell infiltration levels were significantly associated with the expression of the seven DE-MTGs. Finally, a nomogram was established by incorporating the prognostic gene signature and clinical parameters, which was superior to the AJCC staging system in predicting the OS of PDAC patients.

Conclusions: The DE-MTGs we identified were closely associated with the progress and prognosis of PDAC and are potential therapeutic targets. The MTG-based gene signature and nomogram may serve to improve the individualized prediction of survival, assisting in clinical decision-making.

Impaired Metabolic Pathways Related to Colorectal Cancer Progression and Therapeutic Implications

BACKGROUND

Risk of colorectal cancer (CRC) is defined by genetic predisposition and environmental factors that often co-occur and interact, resulting in diversiform biological reactions. The present study attempted to investigate transcriptome alteration and adaptation associated with CRC progression.

METHODS

The study consisted of patients who presented at Memorial Sloan-Kettering Cancer Center, Guangzhou, China with a colonic neoplasm in 1992-2004. Microarray GSE41258 of the study was acquired from Gene Expression Omnibus and 253 included microarrays were categorized by groups of normal colon, early primary tumor, lymph node metastases primary tumor, advanced primary tumor and distant metastases. Short Time-series Expression Miner (STEM) was applied to discover tumor grade-dependent gene expression patterns. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were carried out to explore functional enrichment of differential expression genes (DEGs).

RESULTS

Overall, 2870 significant DEGs were screened out on all groups. Six significant grade-dependent gene expression patterns were statistically significant. DEGs in all significant patterns were mainly assembled in GO terms of metastases and deterioration of tumor, epithelial proteins and cytokines, and protein binding and bridging. DEGs in profile 0 down-regulated with higher tumor grade, prominently enriched in KEGG pathways of metabolism.

CONCLUSION

Besides many well-known colorectal cancer-related pathways, DEGs of profiles especially those down-regulated with CRC progression, clustered in various metabolic pathways including starch and sucrose metabolism, fatty acid metabolism, nitrogen metabolism, as well as xenobiotics biotransformation that link to tumorigenesis, demonstrating the impairment of physiological metabolic pathways in the context of tumor progression. These results gave a high potential for therapeutic strategies.

Establishment of a novel experimental model for muscle-invasive bladder cancer using a dog bladder cancer organoid culture

In human and dogs, bladder cancer (BC) is the most common neoplasm affecting the urinary tract. Dog BC resembles human muscle‐invasive BC in histopathological characteristics and gene expression profiles, and could be an important research model for this disease. Cancer patient‐derived organoid culture can recapitulate organ structures and maintains the gene expression profiles of original tumor tissues. In a previous study, we generated dog prostate cancer organoids using urine samples, however dog BC organoids had never been produced. Therefore we aimed to generate dog BC organoids using urine samples and check their histopathological characteristics, drug sensitivity, and gene expression profiles. Organoids from individual BC dogs were successfully generated, expressed urothelial cell markers (CK7, CK20, and UPK3A) and exhibited tumorigenesis in vivo. In a cell viability assay, the response to combined treatment with a range of anticancer drugs (cisplatin, vinblastine, gemcitabine or piroxicam) was markedly different in each BC organoid. In RNA‐sequencing analysis, expression levels of basal cell markers (CK5 and DSG3) and several novel genes (MMP28,CTSE,CNN3,TFPI2,COL17A1, and AGPAT4) were upregulated in BC organoids compared with normal bladder tissues or two‐dimensional (2D) BC cell lines. These established dog BC organoids might be a useful tool, not only to determine suitable chemotherapy for BC diseased dogs but also to identify novel biomarkers in human muscle‐invasive BC. In the present study, for the 1st time, dog BC organoids were generated and several specifically upregulated organoid genes were identified. Our data suggest that dog BC organoids might become a new tool to provide fresh insights into both dog BC therapy and diagnostic biomarkers.

Upregulation and Nuclear Location of MMP28 in Alveolar Epithelium of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive aging-associated disease of unknown etiology. A growing body of evidence indicates that aberrant activated alveolar epithelial cells induce the expansion and activation of the fibroblast population, leading to the destruction of the lung architecture. Some matrix metalloproteinases (MMPs) are upregulated in IPF, indicating that they may be important in the pathogenesis and/or progression of IPF. In the present study, we examined the expression of MMP28 in this disease and evaluated its functional effects in two alveolar epithelial cell lines and in human primary bronchial epithelial cells. We found that the enzyme is expressed in bronchial (apical and cytoplasmic localization) and alveolar (cytoplasmic and nuclear localization) epithelial cells in two different groups of patients with IPF. In vitro MMP28 epithelial silencing decreased the proliferation rate and delayed wound closing, whereas overexpression showed opposite effects, protecting from apoptosis and enhanced epithelial-mesenchymal transition. Our findings demonstrate that MMP28 is upregulated in epithelial cells from IPF lungs, where it may play a role in increasing the proliferative and migratory phenotype in a catalysis-dependent manner.

Upregulated MMP28 in Hepatocellular Carcinoma Promotes Metastasis via Notch3 Signaling and Predicts Unfavorable Prognosis

MMP28 belongs to the matrix metalloproteinases (MMPs) family and functions in tissue homeostasis and development. Although many other MMPs have been reported to regulate tumor progression, the roles of MMP28 in cancer remain largely elusive. In this study, we investigated the potential roles of MMP28 in hepatocellular carcinoma (HCC). The upregulation of MMP28 was first determined by the analysis on different public datasets. Further quantitative real-time PCR (qPCR) analysis, western blot (WB) assay and immunohistochemistry (IHC) assay on tumor and tumor-adjacent samples from HCC patients confirmed the aberrant elevation of MMP28 in HCC. Pathological analysis showed that increased MMP28 was associated with tumor size, vascular invasion, TNM stage and overall survival in HCC patients. Meanwhile, upregulated MMP28 was identified as an independent prognosis factor in multivariate analysis, and the incorporation of MMP28 expression with TNM staging system established a novel model to improve the accuracy of the predictions. In vivo and in vitro data revealed that MMP28 promoted migration and invasion of HCC cells, and enhanced epithelial-mesenchymal transition (EMT) via elevating zinc finger E-box binding homeobox (ZEB) homologues levels. Furthermore, we determined that Notch3 signaling was critical for the functions of MMP28 in HCC. In conclusion, upregulated MMP28 in HCC promoted migration and invasion and predicted poor prognosis for HCC patients, and the effects of MMP28 depended on Notch3 signaling.

A SUV39H1-low chromatin state characterises and promotes migratory properties of cervical cancer cells

Metastatic progression is a major cause of mortality in cervical cancers, but factors regulating migratory and pre-metastatic cell populations remain poorly understood. Here, we sought to assess whether a SUV39H1-low chromatin state promotes migratory cell populations in cervical cancers, using meta-analysis of data from The Cancer Genome Atlas (TCGA), immunohistochemistry, genomics and functional assays. Cervical cancer cells sorted based on migratory ability in vitro have low levels of SUV39H1 protein, and SUV39H1 knockdown in vitro enhanced cervical cancer cell migration. Further, TCGA SUV39H1-low tumours correlated with poor clinical outcomes and showed gene expression signatures of cell migration. SUV39H1 expression was examined within biopsies, and SUV39H1^low cells within tumours also demonstrated migratory features. Next, to understand genome scale transcriptional and chromatin changes in migratory populations, cell populations sorted based on migration in vitro were examined using RNA-Seq, along with ChIP-Seq for H3K9me3, the histone mark associated with SUV39H1. Migrated populations showed SUV39H1-linked migratory gene expression signatures, along with broad depletion of H3K9me3 across gene promoters. We show for the first time that a SUV39H1-low chromatin state associates with, and promotes, migratory populations in cervical cancers. Our results posit SUV39H1-low cells as key populations for prognosis estimation and as targets for novel therapies.

Identification of MMP28 as a biomarker for the differential diagnosis of idiopathic pulmonary fibrosis

Background and objective

Idiopathic Pulmonary Fibrosis (IPF) is a progressive disease of unknown etiology. The diagnosis is based on the identification of a pattern of usual interstitial pneumonia either by high resolution computed tomography and/or histology. However, a similar pattern can be observed in other fibrotic lung disorders, and precise diagnosis remains challenging. Studies on biomarkers contributing to the differential diagnosis are scanty, and still in an exploratory phase. Our aim was to evaluate matrix metalloproteinase (MMP)-28, which has been implicated in abnormal wound healing, as a biomarker for distinguishing IPF from fibrotic non-IPF patients.

Methods

The cell localization of MMP28 in lungs was examined by immunohistochemistry and its serum concentration was measured by ELISA in two different populations. The derivation cohort included 82 IPF and 69 fibrotic non-IPF patients. The validation cohort involved 42 IPF and 41 fibrotic non-IPF patients.

Results

MMP28 was detected mainly in IPF lungs and localized in epithelial cells. In both cohorts, serum concentrations of MMP28 were significantly higher in IPF versus non-IPF (mostly with lung fibrosis associated to autoimmune diseases and chronic hypersensitivity pneumonitis) and healthy controls (ANOVA, p<0.0001). The AUC of the derivation cohort was 0.718 (95%CI, 0.635–0.800). With a cutoff point of 4.5 ng/mL, OR was 5.32 (95%CI, 2.55–11.46), and sensitivity and specificity of 70.9% and 69% respectively. The AUC of the validation cohort was 0.690 (95%CI, 0.581–0.798), OR 4.57 (95%CI, 1.76–12.04), and sensitivity and specificity of 69.6% and 66.7%. Interestingly, we found that IPF patients with definite UIP pattern on HRCT showed higher serum concentrations of MMP28 than non-IPF patients with the same pattern (7.8±4.4 versus 4.9±4.4; p = 0.04). By contrast, no differences were observed when IPF with possible UIP-pattern were compared (4.7±3.2 versus 3.9±3.0; p = 0.43).

Conclusion

These findings indicate that MMP28 might be a useful biomarker to improve the diagnostic certainty of IPF.

Overexpression of MMP21 and MMP28 is associated with gastric cancer progression and poor prognosis

Matrix metalloproteinase (MMP)-21 and MMP-28, or epilysin, are overexpressed during the invasion and metastasis of solid tumors. The present study investigated MMP-21 and MMP-28 expression levels in human gastric cancer using tissue microarray (TMA) analysis, and determined their association with clinicopathological characteristics and patient prognosis. TMA blocks, including 436 cases of gastric cancer and 92 non-cancerous adjacent gastric tissues, were investigated using immunohistochemistry. Staining results were analyzed statistically in association with various clinicopathological characteristics and overall survival. The MMP-21 and MMP-28 positive detection rate was 31.9% (139/436) and 34.4% (150/436), respectively, in the gastric carcinoma tissue specimens. MMP-21 and MMP-28 expression levels were negative in the 92 normal gastric tissue samples. In patients with gastric cancer, positive expression of MMP-21 and MMP-28 was correlated with tumor diameter, depth of invasion, vessel invasion, lymph node and distant metastases and tumor-node-metastasis stage. The overall survival rate was significantly lower in MMP-21 and MMP-28-positive compared with negative patients. Cox multivariate analysis revealed that MMP-21 and MMP-28 levels were independent predictors of survival in patients with gastric cancer. These findings emphasize the importance of MMP-21 and MMP-28, which may serve as novel and independent prognostic markers for the invasion and metastasis of human gastric cancer.

Downregulated CDK10 expression in gastric cancer: Association with tumor progression and poor prognosis

The tumor suppressor characteristics of cyclin‑dependent kinase 10 (CDK10) in nasopharyngeal carcinoma and breast cancer have been previously demonstrated. In the present study the expression status of CDK10 and its prognostic significance in gastric cancer was determined, as well as its role in cell proliferation and invasion. Immunoblot analysis revealed that CDK10 protein expression was notably decreased in gastric cancer compared with normal tissues. Immunohistochemistry demonstrated that the loss of CDK10 expression, which was observed in 50.8% of primary gastric cancer tissues (n=128), significantly correlated with advanced tumor stage (P<0.001), frequent lymph node metastasis (P<0.001), distant metastasis (P=0.013), tumor differentiation (P=0.004) and unfavorable overall survival (P<0.001). Multivariate analysis suggested that CDK10 expression may serve as an independent prognostic predictor (P=0.001) for the progression of gastric cancer. In addition, ectopic CDK10 expression inhibited gastric cancer cell proliferation, migration and invasion, while knockdown of CDK10 promoted these phenotypes. Collectively, the results of the present study indicated that CDK10 expression may serve as a novel prognostic biomarker that holds therapeutic promise for gastric cancer.

Profile of Expression of Genes Encoding Matrix Metallopeptidase 9 (MMP9), Matrix Metallopeptidase 28 (MMP28) and TIMP Metallopeptidase Inhibitor 1 (TIMP1) in Colorectal Cancer: Assessment of the Role in Diagnosis and Prognostication

Background

Studies on the pathomechanism of colorectal cancer (CRC) expansion indicate a significant role of metalloproteinases and their inhibitors in the extracellular matrix. The results of the analysis of a profile of transcriptional activity of genes encoding metalloproteinases were the basis of the hypothesis indicating changes in the expression of genes encoding MMP9, MMP28, and TIMP1 as an additional diagnostic and prognostic marker of CRC.

Material/Methods

The material consisted of samples obtained from resected tumors and healthy tissue samples from 15 CRC patients (aged 46–72 years) at clinical stages (CSs) I and II–IV.

Gene expression analysis was done using microarrays. Microarray data analysis was done using the GeneSpring 11.5 platform. The results were validated using the qRT-PCR technique.

Results

We found high levels of expression of MMP9 at each CS, as well as in the tissues at the early stage of CRC. Additionally, we observed high levels of expression of TIMP1 and low levels of MMP28 genes in CS II–IV. No statistically significant differences based on the stage of CRC were observed.

Conclusions

MMP9 gene profile may be a complementary diagnostic marker in CRC. The results suggest a crucial role of MMP9 at the early stage of carcinogenesis in the large intestine. The increase in MMP9 and TIMP1 mRNA concentration and the decrease in MMP28 in the large intestinal tissue may be a confirmation of cancer, but it may not indicate the advance of CRC.

Matrix-metalloproteinases as targets for controlled delivery in cancer: An analysis of upregulation and expression

While commonly known for degradation of the extracellular matrix, matrix metalloproteinases (MMPs) exhibit broad potential for use in targeting of bioactive and imaging agents in cancer treatment. MMPs are upregulated at all stages of expression in cancers. A comprehensive analysis of published literature on expression of all MMP subtypes at the genetic, protein, and activity levels in normal and diseased tissues indicate targeting applicability in a variety of cancers. This expression significantly increases at advanced cancer stages, providing an improved opportunity for controlled release in higher-stage patients. Since MMPs are integral at every stage of metastasis, MMP roles in cancer are discussed with a focus on MMP distribution and mobility within cells and tumors for cancer targeting applications. Several strategies for MMP utilization in targeting - such as matrix degradation, MMP cleavage, MMP binding, and MMP-induced environmental changes - are addressed.

Artesunate inhibits the growth and induces apoptosis of human gastric cancer cells by downregulating COX-2

Artesunate, a derivative of artemisinin isolated from Artemisia annua L., has been traditionally used to treat malaria, and artesunate has demonstrated cytotoxic effects against a variety of cancer cells. However, there is little available information about the antitumor effects of artesunate on human gastric cancer cells. In the present study, we investigated the antitumor effect of artesunate on human gastric cancer cells and whether its antitumor effect is associated with reduction in COX-2 expression. The effects of artesunate on the growth and apoptosis of gastric cancer cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis of annexin V-fluorescein isothiocyanate/propidium iodide staining, rhodamine 123 staining, and Western blot analysis. Results indicate that artesunate exhibits antiproliferative effects and apoptosis-inducing activities. Artesunate markedly inhibited gastric cancer cell proliferation in a time- and dose-dependent manner and induced apoptosis in gastric cancer cells a dose-dependent manner, which was associated with a reduction in COX-2 expression. Treatment with the selective COX-2 inhibitor celecoxib, or transient transfection of gastric cancer cells with COX-2 siRNA, also inhibited cell proliferation and induced apoptosis. Furthermore, the treatment with artesunate promoted the expression of proapoptotic factor Bax and suppressed the expression of antiapoptotic factor Bcl-2. In addition, caspase-3 and caspase-9 were activated, and artesunate induced loss of mitochondrial membrane potential, suggesting that the apoptosis is mediated by mitochondrial pathways. These results demonstrate that artesunate has an effect on anti-gastric cancer cells. One of the antitumor mechanisms of artesunate may be that its inhibition of COX-2 led to reduced proliferation and induction of apoptosis, connected with mitochondrial dysfunction. Artesunate might be a potential therapeutic agent for gastric cancer.

Inhibition of the p38 MAPK pathway sensitizes human gastric cells to doxorubicin treatment in vitro and in vivo

Gastric cancer is the second most common cause of cancer-related deaths worldwide. Doxorubicin-based chemotherapeutic regimes have been the mainstay of systemic treatment for disseminated gastric cancer for numerous years. However, the efficacy of doxorubicin is severely limited due to chemoresistance. Chemoresistance is a tightly regulated process, under the control of numerous signal transduction pathways. Amongst these, the mitogen-activated protein kinase (MAPK) pathway has received much attention. This study assessed whether the p38 MAPK pathway is involved in doxorubicin resistance in gastric cancer cells. Doxorubicin alone or combined with the p38 MAPK pathway inhibitor SB203580 was used to treat gastric cancer cells (SGC7901 and BGC823 lines). The effect of doxorubicin on the growth and apoptosis of gastric cancer cells in the presence or absence of SB203580 was investigated by western blot analysis, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Hoechst staining, Annexin V-FITC/propidium iodide staining followed by flow cytometry analysis, and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Next, the effects of doxorubicin and SB203580, on the sensitivity of BGC-823 cells were assessed in a tumor xenograft model. The results showed that the p38 MAPK inhibitor significantly increases gastric cancer cell sensitivity to doxorubicin. Doxorubicin in combination with SB203580 significantly reduced cell viability (P<0.01) and increased cell death (P<0.01), which may be associated with the inactivation of the p38 MAPK signaling pathway, followed by the induced expression of the pro-apoptotic protein Bax and a concomitant decrease in Bcl-2 expression. These findings suggest that p38 MAPK is involved in gastric cancer cell survival, and that the inhibition of p38 MAPK signaling can reduce the tolerance of gastric cancer cells to doxorubicin treatment.

Matrix metalloproteinase 12 is induced by heterogeneous nuclear ribonucleoprotein K and promotes migration and invasion in nasopharyngeal carcinoma

Background

Overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a DNA/RNA binding protein, is associated with metastasis in nasopharyngeal carcinoma (NPC). However, the mechanisms underlying hnRNP K-mediated metastasis is unclear. The aim of the present study was to determine the role of matrix metalloproteinase (MMP) in hnRNP K-mediated metastasis in NPC.

Methods

We studied hnRNP K-regulated MMPs by analyzing the expression profiles of MMP family genes in NPC tissues and hnRNP K-knockdown NPC cells using Affymetrix microarray analysis and quantitative RT-PCR. The association of hnRNP K and MMP12 expression in 82 clinically proven NPC cases was determined by immunohistochemical analysis. The hnRNP K-mediated MMP12 regulation was determined by zymography and Western blot, as well as by promoter, DNA pull-down and chromatin immunoprecipitation (ChIP) assays. The functional role of MMP12 in cell migration and invasion was demonstrated by MMP12-knockdown and the treatment of MMP12-specific inhibitor, PF-356231.

Results

MMP12 was overexpressed in NPC tissues, and this high level of expression was significantly correlated with high-level expression of hnRNP K (P = 0.026). The levels of mRNA, protein and enzyme activity of MMP12 were reduced in hnRNP K-knockdown NPC cells. HnRNP K interacting with the region spanning −42 to −33 bp of the transcription start site triggered transcriptional activation of the MMP12 promoter. Furthermore, inhibiting MMP12 by MMP12 knockdown and MMP12-specific inhibitor, PF-356231, significantly reduced the migration and invasion of NPC cells.

Conclusions

Overexpression of MMP12 was significantly correlated with hnRNP K in NPC tissues. HnRNP K can induce MMP12 expression and enzyme activity through activating MMP12 promoter, which promotes cell migration and invasion in NPC cells. In vitro experiments suggest that NPC metastasis with high MMP12 expression may be treated with PF-356231. HnRNP K and MMP12 may be potential therapeutic markers for NPC, but additional validation studies are warranted.

Elevated levels of serum fatty acid synthase in patients with gastric carcinoma

Gastric cancer is the second leading cause of cancer mortality in the world. It is important to develop biomarkers for detecting new cancers at an early stage and for treating them early during recurrence in order to guide optimal treatment. Fatty acid synthase (FAS) is highly expressed in numerous human cancers and thus could potentially serve as such a biomarker, but the potential utility of measuring FAS for detecting gastric cancer has not been previously investigated. The aim of the present study was to provide a preliminary assessment of serum FAS as a marker of gastric carcinoma. The study included 47 patients with gastric cancer and 150 healthy subjects. Blood samples were collected from each cancer patient prior to treatment. Serum FAS levels were measured by ELISA and compared across the two groups of patients. Significantly higher levels of serum FAS were found in the gastric cancer patients [95% confidence interval (CI), 30.37–52.46] compared with the healthy controls (95% CI, 1.331–2.131), with elevated levels even in patients with early-stage tumors. These results indicate that measuring serum FAS levels has strong potential to provide a biomarker for the detection of gastric cancer, with high sensitivity and specificity.

β,β-carotene 15,15'-monooxygenase and its substrate β-carotene modulate migration and invasion in colorectal carcinoma cells

BACKGROUND

β,β-Carotene 15,15'-monooxygenase (BCMO1) converts β-carotene to retinaldehyde. Increased β-carotene consumption is linked to antitumor effects. Retinoic acid reduces the invasiveness in cancer, through inhibition of matrix metalloproteinases (MMPs). In our studies of a mouse model that develops intestinal tumors after low dietary folate, we found reduced BCMO1 expression in normal preneoplastic intestine of folate-deficient tumor-prone mice.

OBJECTIVE

Our goal was to determine whether BCMO1 expression could influence transformation potential in human colorectal carcinoma cells, by examining the effect of BCMO1 modulation on cellular migration and invasion, and on expression of MMPs.

DESIGN

LoVo colon carcinoma cells were transfected with BCMO1 small interfering RNA (siRNA) or scrambled siRNA. Migration and invasion were measured, and the expression of BCMO1, MMP7, and MMP28 was assessed by quantitative reverse-transcriptase polymerase chain reaction. These variables were also measured after treatment of cells with retinoic acid, 5-aza-2'-deoxycytidine, folate-depleted/high-methionine medium, and β-carotene.

RESULTS

Retinoic acid decreased the migration, invasion, and expression of MMP28 mRNA. Transfection of cells with BCMO1 siRNA inhibited BCMO1 expression, enhanced migration and invasion, and increased expression of MMP7 and MMP28. 5-Aza-2'-deoxycytidine decreased, whereas folate-depleted/high-methionine medium increased invasiveness. β-Carotene increased BCMO1 expression and reduced invasiveness with a decrease in expression of MMP7 and MMP28.

CONCLUSIONS

Inhibition of BCMO1 expression is associated with increased invasiveness of colon cancer cells and increased expression of MMP7 and MMP28. β-Carotene can upregulate BCMO1 and reverse these effects. These novel associations suggest a critical role for BCMO1 in cancer and provide a mechanism for the proposed antitumor effects of β-carotene.

Inhibition of the ecto-beta subunit of F1F0-ATPase inhibits proliferation and induces apoptosis in acute myeloid leukemia cell lines

BACKGROUND

Leukemia, a heterogeneous clonal disorder of hematopoietic progenitor cells, presents a world-wide health problem, especially in childhood. F1F0 ATPase, an inner mitochondrial enzyme, is expressed on the plasma membrane of tumor cells, and its inhibition induces both anti-angiogenic and anti-tumorigenic activity.

METHODS

Monoclonal Antibody (McAb) against ATPase was produced by polyethylene glycol-mediated fusions and screened by ELISA. Proliferation, cell cycle and apoptosis of cells were analyzed when the surface ATPase of cells was blockaded with McAb.

RESULTS

We detected cell-membrane expression of the F1F0 ATPase β subunit on 0.1% to 56% of the 11 cell lines derived from leukemia, including acute myeloid leukemia (AML). We produced a monoclonal antibody, McAb7E10, which recognizes both the native and recombinant ATPase β subunit, with a dissociation constant (KD) of 3.26E-10. We demonstrate that McAb7E10 binds to ATPase at the cell surface, where it is able to inhibit ATP synthesis. McAb7E10 significantly inhibited proliferation of AML cell lines in vitro: the relative inhibitory rates of 50 μg/mL McAb7E10 treated MV4-11and HL-60 cells were 69.6% and 81.9% respectively. Cell cycle analysis indicated that McAb7E10 significantly induced apoptosis in MV4-11 and HL-60 cells: the relative rates of apoptosis in 5, 10 and 50ug/mL McAb7E10 treated MV4-11 cells was 3.6 ± 0.83%, 8.4 ± 1.69% and 17.3 ± 2.56% compared to 1.5% ± 0.85% in mouse IgG treated cells (p < 0.01). The relative rate of apoptosis in 5, 10 and 50ug/mL McAb7E10 treated HL-60 cells was 5.5 ± 2.37%, 11.3 ± 3.62% and 19.9 ± 3.31% compared to 1.56% ± 0.97% in mouse IgG treated cells (p < 0.01). Annexin V staining demonstrated that the relative apoptotic rates in 50 μg/mL McAb7E10 treated MV4-11 and HL-60 cells were 50.5% ± 7.04% and 32.9% ± 4.52%, respectively, significantly higher than IgG control antibody treated cells were 21.9% ± 3.11% and 15.3% ± 3.95%, p < 0.01.

CONCLUSIONS

These findings indicate that ectopic expression of ATPase β subunit may be a tumor-associated antigen in hematological malignancies. The F1F0 ATPase β subunit provides a potential target for immunotherapy in AML and hematological malignancies.

Dickkopf-1 expression is a novel prognostic marker for gastric cancer

AIM

To investigate the involvement of Dickkopf-1 expression in gastric cancer.

METHODS

Dickkopf-1 mRNA and protein expression were determined by real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunohistochemistry in specimens of primary cancer and their adjacent noncancerous tissues in gastric cancer patients.

RESULTS

Dickkopf-1 mRNA and protein expression levels were both significantly upregulated in gastric cancer lesions compared with adjacent noncancerous tissues. Its positive expression was correlated with depth of invasion, vessel invasion, lymph node and distant metastasis, and TNM stage of tumors. Additionally, in stages I, II, and III gastric cancers, the 5- year survival rate of patients with a high expression of Dickkopf-1 was significantly lower than that in patients with low expression. In stage IV, Dickkopf-1 expression did not correlate with the 5-year survival rate. Further multivariate analysis suggested that the up-regulation of Dickkopf-1 was an independent prognostic indicator for gastric cancer.

CONCLUSION

A subset of cases with gastric cancer revealed the up-regulation of Dickkopf-1, which was associated with a progressive pathological feature and an aggressive clinical course. Therefore, Dickkopf-1 expression may be predictor for poor prognosis in patients with gastric cancer. This is the first report describing the involvement of Dickkopf-1 in gastric cancer.

ATP synthase ecto-α-subunit: a novel therapeutic target for breast cancer

Background

Treatment failure for breast cancer is frequently due to lymph node metastasis and invasion to neighboring organs. The aim of the present study was to investigate invasion- and metastasis-related genes in breast cancer cells in vitro and in vivo. Identification of new targets will facilitate the developmental pace of new techniques in screening and early diagnosis. Improved abilities to predict progression and metastasis, therapeutic response and toxicity will help to increase survival of breast cancer patients.

Methods

Differential protein expression in two breast cancer cell lines, one with high and the other with low metastatic potential, was analyzed using two-dimensional liquid phase chromatographic fractionation (Proteome Lab PF 2D system) followed by matrix-assisted laser desorption/time-of-flight mass spectrometry (MALDI-TOF/MS).

Results

Up regulation of α-subunit of ATP synthase was identified in high metastatic cells compared with low metastatic cells. Immunohistochemical analysis of 168 human breast cancer specimens on tissue microarrays revealed a high frequency of ATP synthase α-subunit expression in breast cancer (94.6%) compared to normal (21.2%) and atypical hyperplasia (23%) breast tissues. Levels of ATP synthase expression levels strongly correlated with large tumor size, poor tumor differentiation and advanced tumor stages (P < 0.05). ATP synthase α-subunit over-expression was detected on the surface of a highly invasive breast cancer cell line. An antibody against the ATP synthase α-subunit inhibited proliferation, migration and invasion in these breast cancer cells but not that of a non-tumor derived breast cell line.

Conclusions

Over-expression of ATP synthase α-subunit may be involved in the progression and metastasis of breast cancer, perhaps representing a potential biomarker for diagnosis, prognosis and a therapeutic target for breast cancer. This finding of this study will help us to better understand the molecular mechanism of tumor metastasis and to improve the screening, diagnosis, as well as prognosis and/or prediction of responses to therapy for breast cancer.

Human matrix metalloproteinases: an ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes.

An novel role of sphingosine kinase-1 (SPHK1) in the invasion and metastasis of esophageal carcinoma

Background

Treatment failure for esophageal carcinoma is frequently due to lymph node metastasis and invasion to neighboring organs. The aim of the present study was to investigate invasion- and metastasis-related genes in esophageal carcinoma cells in vitro and in vivo.

Methods

A metastasis model using a Matrigel invasion clonal selection approach was employed to establish a highly invasive subline EC9706-P4 from the esophageal carcinoma cell (ESCC) line EC9706. The differentially expressed genes of the subline and the parental cells determined by gene microarrays were further analyzed by RT-PCR and Western blotting.

Results

We identified sphingosine kinase 1 (SPHK1) as an invasion and metastasis-related gene of esophageal cancer. SPHK1 was overexpressed in the EC9706-P4 subline with high invasive capacity. Among six ESCC lines tested, KYSE2 and KYSE30 cells showed the highest SPHK1 mRNA and protein expressions as well as the most invasive phenotype. By Western blotting, in 7/12 cases (58%), SPHK1 expression was higher in esophageal carcinomas than in the companion normal tissue. In 23/30 cases (76%), SPHK1 protein expression was upregulated in the tumors compared to matched normal tissue by immunohistochemistry (IHC). Esophageal carcinoma tissue microarray analysis indicated that SPHK1 expression correlated with the depth of tumor invasion (P < 0.0001) and lymph node metastasis (P = 0.016). By Kaplan-Meier analysis, strong SPHK1 expression was significantly associated with clinical failure (P < 0.01), suggesting the involvement of SPHK1 in aggressiveness of human esophageal carcinoma. SPHK1 overexpression significantly increased the invasiveness of EC9706 cells in vitro and also increased EC9706 cell growth and spontaneous metastasis in vivo, promoting significant increases in tumor growth, tumor burden and spontaneous lung metastasis in nude mice. SPHK1 expression significantly correlated with the expression of many EGFR pathway genes associated with invasion of cancer cells. SPHK1 protein expression also significantly correlated with the phosphorylation of EGFR.

Conclusion

In summary, our data implicate SPHK1 in the metastasis of esophageal cancer. Our study also identified downstream mediators of SPHK1 in esophageal cancer cells that may mediate enhanced malignant behavior, and several of these mediators may be useful as therapeutic targets.