Epigenetic inactivation of the metastasis suppressor RECK enhances invasion of human colon cancer cells

Methylation degree of metalloproteinase inhibitor RECK gene: Links to RECK protein level and hepatocellular carcinoma in chronic HCV infection patients

The RECK gene, a tumor suppressor gene, inhibits angiogenesis, invasion, and tumor metastasis. Epigenetic regulation of the RECK gene constitutes a potent approach to the molecular basis of liver malignancy. This study aims to evaluate the promoter methylation status of the RECK gene and its serum level in patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) and the potential association of RECK gene methylation with clinical criteria of HCC. One hundred and fifty-five subjects were included (healthy control [55], chronic HCV patients [55], HCV-related HCC patients [45]). The methylation status of the RECK gene promoter and serum RECK level were investigated by methylation-specific PCR and enzyme-linked immunosorbent assay techniques, respectively. RECK gene promoter hypermethylation was recorded in 46.7% of HCC patients, and 10.9% of HCV patients, but not in control subjects (0%). It was related to RECK protein level, varices, edema, ascites, lymph node metastasis, vascular invasion, and the largest diameter of focal lesions. Meanwhile, it was not associated with focal lesion number nor distant metastasis of HCC. In conclusion, RECK gene promoter hypermethylation is linked to HCV genotype-4-related HCC. Moreover, different degrees of RECK gene promoter methylation are associated with serum RECK level, lymph node metastasis, and vascular invasion, which could prove its pathogenic role in hepatocarcinogenesis in chronic HCV-infected patients.

Epigenetic regulation in the pathogenesis of non-melanoma skin cancer

Understanding of cancer with the help of ever-expanding cutting edge technological tools and bioinformatics is revolutionizing modern cancer research by broadening the space of discovery window of various genomic and epigenomic processes. Genomics data integrated with multi-omics layering have advanced cancer research. Uncovering such layers of genetic mutations/modifications, epigenetic regulation and their role in the complex pathophysiology of cancer progression could lead to novel therapeutic interventions. Although a plethora of literature is available in public domain defining the role of various tumor driver gene mutations, understanding of epigenetic regulation of cancer is still emerging. This review focuses on epigenetic regulation association with the pathogenesis of non-melanoma skin cancer (NMSC). NMSC has higher prevalence in Caucasian populations compared to other races. Due to lack of proper reporting to cancer registries, the incidence rates for NMSC worldwide cannot be accurately estimated. However, this is the most common neoplasm in humans, and millions of new cases per year are reported in the United States alone. In organ transplant recipients, the incidence of NMSC particularly of squamous cell carcinoma (SCC) is very high and these SCCs frequently become metastatic and lethal. Understanding of solar ultraviolet (UV) light-induced damage and impaired DNA repair process leading to DNA mutations and nuclear instability provide an insight into the pathogenesis of metastatic neoplasm. This review discusses the recent advances in the field of epigenetics of NMSCs. Particularly, the role of DNA methylation, histone hyperacetylation and non-coding RNA such as long-chain noncoding (lnc) RNAs, circular RNAs and miRNA in the disease progression are summarized.

Up-regulation of TIMP-3 and RECK decrease the invasion and metastasis ability of colon cancer

BACKGROUND AND STUDY AIMS

Although the function of microRNA21 (miR-21) in the invasion and metastasis of colon cancer has been extensively studied, the mechanisms of invasion and migration related pathways between and its targets are still not elucidated. This study explored the mechanisms of the pathway between miR-21 and the target genes in vitro and in vivo.

MATERIALS AND METHODS

We transfected pmiRZip21 or Leti3 into colon cancer cells. The levels of miR-21 expression, mRNA transcription and protein of target genes were analysed by TaqMan microRNA assays, RT-PCR and western blot, respectively. Scratch migration and trans-well assays were used to evaluate metastasis and invasion. To build a subcutaneous tumour animal model, detect the level of miR-21 and the target genes and then identify the mechanisms in vivo.

RESULTS

MiR-21 expression levels in colon cancer cells transfected with pmiRZip21 in vivo or in vitro were decreased (P < 0.05). The mRNA and protein levels of TIMP-3 and RECK were up-regulated after inhibiting miR-21 in vitro and in vivo (P < 0.05), but those of BMPR-II and PCDH17 were not. In pmiRZip21-transfected colon cancer cells, invasion and migration were significantly decreased both in vitro and vivo (P < 0.05).

CONCLUSIONS

Up-regulation of TIMP-3 and RECK, by inhibiting miR-21 expression can decrease tumour invasion and metastasis ability in vitro and in vivo, and has potential as a possible target site in anti-tumour therapy. More effects in vivo have to be investigated in further research.

Exome-Wide Rare Variant Analysis From the DiscovEHR Study Identifies Novel Candidate Predisposition Genes for Endometrial Cancer

Endometrial cancer is the fourth most commonly diagnosed cancer in women. Family history is a known risk factor for endometrial cancer. The incidence of endometrial cancer in a first-degree relative elevates the relative risk to range between 1.3 and 2.8. It is unclear to what extent or what other novel germline variants are at play in endometrial cancer. We aim to address this question by utilizing whole exome sequencing as a means to identify novel, rare variant associations between exonic regions and endometrial cancer. The MyCode community health initiative is an excellent resource for this study with germline whole exome data for 60,000 patients available in the first phase, and further 30,000 patients independently sequenced in the second phase as part of DiscovEHR study. We conducted exome-wide rare variant association using 472 cases and 4,110 controls in 60,000 patients (discovery cohort); and 261 cases and 1,531 controls from 30,000 patients (replication cohort). After binning rare germline variants into genes, case-control association tests performed using Optimal Unified Approach for Rare-Variant Association, SKAT-O. Seven genes, including RBM12, NDUFB6, ATP6V1A, RECK, SLC35E1, RFX3 (Bonferroni-corrected P < 0.05) and ATP8A1 (suggestive P < 10⁻⁵), and one long non-coding RNA, DLGAP4-AS1 (Bonferroni-corrected P < 0.05), were associated with endometrial cancer. Notably, RECK, and ATP8A1 were replicated from the replication cohort (suggestive threshold P < 0.05). Additionally, a pathway-based rare variant analysis, using pathogenic and likely pathogenic variants, identified two significant pathways, pyrimidine metabolism and protein processing in the endoplasmic reticulum (Bonferroni-corrected P < 0.05). In conclusion, our results using the single-source electronic health records (EHR) linked to genomic data highlights candidate genes and pathways associated with endometrial cancer and indicates rare variants involvement in endometrial cancer predisposition, which could help in personalized prognosis and also further our understanding of its genetic etiology.

Antimetastatic effect of epigenetic drugs, hydralazine and valproic acid, in Ras-transformed NIH 3T3 cells

Introduction

Metastasis involves the accumulation of genetic and epigenetic alterations leading to activation of prometastatic genes and inactivation of antimetastatic genes. Among epigenetic alterations, DNA hypermethylation and histone hypoacetylation are the focus of intense translational research because their pharmacological inhibition has been shown to produce antineoplastic activity in a variety of experimental models.

Aims

This study aimed to evaluate the antimetastatic effect of the DNA-methylation inhibitor, hydralazine, and the histone deacetylase inhibitor, valproic acid.

Methods

NIH 3T3-Ras murine cells were treated with hydralazine and valproic acid to evaluate their effects upon cell proliferation, cell motility, chemotaxis, gelatinase activity, and gene expression. Lung metastases were developed by intravenous injection of NIH 3T3-Ras cells in BALB/c nu/nu mice and then treated with the drug combination.

Results

Treatment induced a growth-inhibitory effect on NIH 3T3-Ras cells, showed a trend toward increased gelatinase activity of MMP2 and MMP9, and inhibited chemotaxis and cell motility. The combination led to a strong antimetastatic effect in lungs of nude mice.

Conclusion

Hydralazine and valproic acid, two repositioned drugs as epigenetic agents, exhibit antimetastatic effects in vitro and in vivo and hold potential for cancer treatment.

Identification of RECK as an evolutionarily conserved tumor suppressor gene for zebrafish malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are a type of sarcoma with poor prognosis due to their complex genetic changes, invasive growth, and insensitivity to chemo- and radiotherapies. One of the most frequently lost chromosome arms in human MPNSTs is chromosome 9p. However, the cancer driver genes located on it remain largely unknown, except the tumor suppressor gene, p16 (INK4)/CDKN2A. Previously, we identified RECK as a tumor suppressor gene candidate on chromosome 9p using zebrafish-human comparative oncogenomics. In this study, we investigated the tumorigenesis of the reck gene using zebrafish genetic models in both tp53 and ribosomal protein gene mutation background. We also examined the biological effects of RECK gene restoration in human MPNST cell lines. These results provide the first genetic evidence that reck is a bona fide tumor suppressor gene for MPNSTs in zebrafish. In addition, restoration of the RECK gene in human MPNST cells leads to growth inhibition suggesting that the reactivation of RECK could serve as a potential therapeutic strategy for MPNSTs.

Pattern of RECK CpG methylation as a potential marker for predicting breast cancer prognosis and drug-sensitivity

The membrane-anchored glycoprotein RECK negatively regulates multiple metalloproteinases and is frequently downregulated in tumors. Forced RECK expression in cancer cells results in suppression of tumor angiogenesis, invasion, and metastasis in xenograft models. A previous methylome study on breast cancer tissues detected inverse correlation between RECK CpG methylation (in an intron-1 region) and relapse-free survival. In this study, we focused on another region of the RECK CpG island (a promoter/exon-1 region) and found an inverse correlation between its methylation and RECK-inducibility by an HDAC inhibitor, MS275, among a panel of breast cancer cell lines (n=15). In clinical samples (n=62), RECK intron-1 methylation was prevalent among luminal breast cancers as reported previously (26 of 38 cases; 68%) and particularly enriched in tumors of the ER+PR- subclass (10 of 10 cases) and of higher histological grades (Grade 2 and 3; 28 of 43 cases; P=0.006). In about a half of these cases, promoter/exon-1 methylation was absent, and hence, RECK may be inducible by certain drugs such as MS275. Our results indicate the value of combined use of two RECK methylation markers for predicting prognosis and drug-sensitivity of breast cancers.

Hypomethylation reduced the aggressive potential of human malignant mesothelioma cells

Epigenetic modifications have been implicated in the development of therapeutic resistance responsible for the poor prognosis of human malignant mesothelioma (HMM). To find a potential way to overcome this therapeutic resistance, this study investigated the anticancer effects of a DNA demethylating agent, 5-Aza-2'-Deoxycytidine (5-aza-dC), on HMM cells. The 5-aza-dC exhibited minimal detrimental effects on cell survival. However, treatment with 5-aza-dC significantly altered the biological characteristics associated with malignancy, such as cell migration and cell interaction, colony-forming capacity, and invasiveness. Moreover, it significantly reduced the fraction of side population (SP) cells, which are reportedly enriched for more aggressive cells. Large-scale methylation analysis based on methylated DNA immunoprecipitation revealed a more than two fold increase in the methylation level of major tumor suppressor genes in the SP fraction. The data indicated that SP cells might acquire malignancy by hypermethylation of tumor suppressor genes. Treatment with 5-aza-dC could attack more malignant cells through the modification of their methylation status. The results indicate that the modulation of DNA methylation might be a valuable strategy to overcome the therapeutic resistance of HMM. Moreover, ensuing changes in the biological characteristics provide a basis for further analysis of the role of methylation in HMM carcinogenesis.

Epigenetic silencing of NTSR1 is associated with lateral and noninvasive growth of colorectal tumors

Our aim was to identify DNA methylation changes associated with the growth pattern and invasiveness of colorectal cancers (CRCs). Comparison of the methylation statuses of large (≥20 mm in diameter along the colonic surface) noninvasive tumors (NTs) and small (<20 mm in diameter along the colonic surface) invasive tumors (ITs) using CpG island microarray analysis showed neurotensin receptor 1 (NTSR1) to be hypermethylated in large NTs. Quantitative bisulfite pyrosequencing revealed that NTSR1 is frequently methylated in colorectal tumors, with large NTs exhibiting the highest methylation levels. The higher NTSR1 methylation levels were associated with better prognoses. By contrast, NTSR1 copy number gains were most frequent among small ITs. Methylation of NTSR1 was associated with the gene's silencing in CRC cell lines, whereas ectopic expression of NTSR1 promoted proliferation and invasion by CRC cells. Analysis of primary tumors composed of adenomatous and malignant portions revealed that NTSR1 is frequently methylated in the adenomatous portion, while methylation levels are generally lower in the cancerous portions. These results suggest that NTSR1 methylation is associated with lateral and noninvasive growth of colorectal tumors, while low levels of methylation may contribute to the malignant potential through activation of NTSR1. Our data also indicate that NTSR1 methylation may be a prognostic biomarker in CRC.

MicroRNA-135b, a HSF1 target, promotes tumor invasion and metastasis by regulating RECK and EVI5 in hepatocellular carcinoma

MicroRNAs (miRNAs) often localize to chromosomal fragile sites and are associated with cancer. In this study, we screened for the aberrant and functional miRNAs in the regions of copy number alterations (CNAs) in hepatocellular carcinoma (HCC), and found that miR-135b was frequently amplified and upregulated in HCC tissues. The expression level of miR-135b was inversely correlated with the occurrence of tumor capsules. In addition, miR-135b promoted HCC cell migration and invasion in vitro and metastasis in vivo. The reversion-inducing-cysteine-rich protein with kazal motifs (RECK) and ecotropic viral integration site 5 (EVI5) were identified as the direct and functional targets of miR-135b in HCC. Furthermore, we observed that heat shock transcription factor 1 (HSF1) directly activated miR-135b expression, consequently enhancing HCC cell motility and invasiveness. The newly identified HSF1/miR-135b/RECK&EVI5 axis provides novel insight into the mechanisms of HCC metastasis, which may facilitate the development of new therapeutics against HCC.

Roles of oxidative stress and the ERK1/2, PTEN and p70S6K signaling pathways in arsenite-induced autophagy

Studies show that arsenite induces oxidative stress and modifies cellular function via phosphorylation of proteins and inhibition of DNA repair enzymes. Autophagy, which has multiple physiological and pathological roles in cellular function, is initiated by oxidative stress and is regulated by the signaling pathways of phosphatidylinositol 3-phosphate kinase (PI3K)/mammalian target of rapamycin (mTOR)/p70S6 kinase (p70S6K) and extracellular signaling-regulated protein kinase 1/2 (ERK1/2) that play important roles in oncogenesis. However, the effects of arsenite-induced oxidative stress on autophagy and on expression of related proteins are not fully understood. This study found that cells treated with sodium arsenite had reduced 8-oxoguanine DNA glycosylase 1 (OGG1) and increased 8-hydroxy-2'-deoxyguanosine (8-OHdG) and activating transcription factor (ATF) 3 in SV-40 immortalized human uroepithelial (SV-HUC-1) cells. Arsenite also increased the number of autophagosomes and increased levels of the autophagy markers Beclin-1 and microtubule-associated protein 1 light chain 3B. Reactive oxygen species scavenger decreased arsenite-induced autophagy in SV-HUC-1 cells. Our previous work showed that arsenite induced phosphorylation of the ERK1/2 signaling pathway. The current study further showed that arsenite decreased phosphatase and tensin homologue (PTEN) levels and increased phospho-p70S6 kinase (p-p70S6K) in SV-HUC-1 cells. However, both kinase inhibitor U0126 and the DNA (cytosine-5-)-methyltransferase 1 (DNMT1) inhibitor 5-aza-deoxycytidine abolished the effect of arsenite on expressions of PTEN and p-p70S6K. These results show that autophagy induced by arsenite exposure is mediated by oxidative stress, which regulates activation of the PTEN, p70S6K and ERK1/2 signaling pathways. Thus, this study clarifies the role of autophagy in arsenite-induced urothelial carcinogenesis.

Epigallocatechin‑3‑gallate inhibits the invasion of salivary adenoid cystic carcinoma cells by reversing the hypermethylation status of the RECK gene

Epigallocatechin‑3‑gallate (EGCG) is an active and major constituent of green tea. As a non‑nucleoside inhibitor of DNA methylation, EGCG is able to inhibit the hypermethylation of newly synthesised DNA, resulting in the reversal of hypermethylation and recovery in expression of the silenced genes. Reversion‑inducing cysteine‑rich protein with Kazal motifs (RECK) is a novel tumour suppressor gene, which negatively regulates matrix metalloproteinases, and inhibits tumour invasion, angiogenesis and metastasis. The present study aimed to examine the effects of EGCG on the methylation status of the RECK gene and tumour invasion in a salivary adenoid cystic carcinoma (SACC) cell line in vitro. Marked levels of methylated and weak levels of unmethylated RECK promoter were detected in the SACC83 cells, which was determined using methylation‑specific polymerase chain reaction (PCR). In addition, the treatment of SACC83 cells with EGCG partially reversed the hypermethylation status of the RECK gene. Western blot analysis and reverse transcription‑PCR demonstrated that EGCG significantly enhanced the protein and mRNA expression levels of RECK, and significantly reduced the invasive ability of the SACC83 cells, as determined using a Transwell assay. These results suggested that EGCG possesses novel anti‑metastatic therapeutic potential for the treatment of SACC.

Natural Compounds: DNA Methyltransferase Inhibitors in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a multistep process which is modulated by several endogenous and environmental factors. Epigenetic changes have been found to be equally responsible for OSCC as genetic changes. A plethora of genes showing hypermethylation have been discovered in OSCC. Since these changes are reversible, a lot of emphasis is on using the natural compounds for their ability to cause demethylation which could lead to reactivation of the inactivated tumor suppressor genes. This review encompasses the promoter hypermethylation of tumor suppressor genes in OSCC and its possible reversal using natural compounds. In addition, new compounds which could be screened for their demethylating ability have also been proposed.

Effects of Decitabine on Invasion and Exosomal Expression of miR-200c and miR-141 in Oxaliplatin-Resistant Colorectal Cancer Cells

The effects of decitabine (DAC), a DNA methyltransferase (DNMT) inhibitor, on metastasis and exosomal expression of microRNAs were examined in SW620/OxR cells, a human colorectal cancer (CRC) cell line (SW620) with acquired resistance to oxaliplatin. This cell line shows an invasive phenotype by epithelial-mesenchymal transition. Two CRC cell lines, SW480, derived from primary CRC, and SW620, derived from lymph node metastasis, which were obtained from the same patient, as well as SW620/OxR, were also used in the present study. Cytarabine (Ara-C), a non-DNMT-inhibiting cytidine analog, was used as negative control of DAC. No significant difference was observed in the invasion abilities of SW480 cells treated with DAC or Ara-C. On the other hand, invasion ability was suppressed by treatment with DAC in SW620 and SW620/OxR cells. Up-regulated expression of E-cadherin, microRNA-200c (miR-200c), and miR-141 following DAC treatment indicated the acquisition of epithelial cell-like characteristics in SW620 and SW620/OxR cells. Exosomal expression levels of miR-200c and miR-141 were also up-regulated by DAC treatment in SW620 and SW620/OxR but not in SW480 cells. This increase in exosomal miRNA expression negatively correlated with invasion ability. These results suggest that DNA demethylation treatment caused acquisition of epithelial cell-like characteristics in SW620 and SW620/OxR cells. Furthermore, the observed increased exosomal expression of miR-200c and miR-141 may be an indicator or biomarker candidate for mesenchymal-epithelial transition of CRC cells.

MicroRNA and targeted mRNA expression profiling analysis in human colorectal adenomas and adenocarcinomas

BACKGROUND

Colorectal cancer (CRC) mainly develops from colorectal adenomas (CRAs). MicroRNAs (miRs) are short non-coding transcripts that regulate gene expression by binding to target mRNAs, preventing their expression. It was suggested that miRs were involved in cancer as tumour suppressors or oncogenes, thereby being also potential cancer biomarkers. We conducted an expression analysis of miRNAs and several of their target mRNAs, by using microarrays and quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) (RT-qPCR), in CRA and CRC, as compared to normal mucosa (NOR), in order to identify candidate miRNAs involved in CRC progression.

RESULTS

Microarray, together with confirmatory RT-qPCR analyses, showed 17 significantly deregulated miRNAs in colorectal lesions. While, as expected, some miRNAs have been previously reported to be associated with CRC, including miR-21 and miR-145, others were new (miR-125a-5p and miR-320 family). Some miRNAs were specific for the CRC versus NOR comparison (miR-320b), or for the CRA versus NOR comparison (miR-15b or miR-16), but several of them (miR-21, miR-24, miR-145, mir-150, miR-378) were deregulated in both CRAs and CRCs, as compared to NOR. The impact of these changes in miR expression on target genes is suggested by the associated deregulation of these genes in CRA and CRC.

CONCLUSIONS

We confirmed that several miRNAs were abnormally expressed in colorectal lesions, identified new deregulated miRs, and showed that several miRNAs could mark the transition from NOR to CRA, thereby marking progression from the early steps of cancer.

Effects of 5-aza-2'deoxycytidine on RECK gene expression and tumor invasion in salivary adenoid cystic carcinoma

Reversion-inducing cysteine-rich protein with kazal motifs (RECK), a novel tumor suppressor gene that negatively regulates matrix metalloproteinases (MMPs), is expressed in various normal human tissues but downregulated in several types of human tumors. The molecular mechanism for this downregulation and its biological significance in salivary adenoid cystic carcinoma (SACC) are unclear. In the present study, we investigated the effects of a DNA methyltransferase (DNMT) inhibitor, 5-aza-2′deoxycytidine (5-aza-dC), on the methylation status of the RECK gene and tumor invasion in SACC cell lines. Methylation-specific PCR (MSP), Western blot analysis, and quantitative real-time PCR were used to investigate the methylation status of the RECK gene and expression of RECK mRNA and protein in SACC cell lines. The invasive ability of SACC cells was examined by the Transwell migration assay. Promoter methylation was only found in the ACC-M cell line. Treatment of ACC-M cells with 5-aza-dC partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression of mRNA and protein, and 5-aza-dC significantly suppressed ACC-M cell invasive ability. Our findings showed that 5-aza-dC inhibited cancer cell invasion through the reversal of RECK gene hypermethylation, which might be a promising chemotherapy approach in SACC treatment.

Role of MTA1 in head and neck cancers

Head and neck cancers usually originate in the squamous cells that line the inner mucosal surfaces of the oral and the neck region. These cancers follow multifocal steps for progression that include risk of developing metastasis. Although therapeutics has advanced in the past decades, head and neck cancers continue to cause much morbidity and mortality. Even with the promising effect of targeted therapies, there is a need for a better evaluation of patients with head and neck cancers. Metastasis-associated tumour antigen 1 (MTA1), a chromatin modifier, is found as an integral part of nucleosome remodelling and histone deacetylation (NuRD) complex. MTA1 is a biomarker for several solid tumours, and the overexpression of which have been documented in various cancers such as breast, ovarian, colon, prostrate etc. Interestingly also, a set of head and neck cancers shows MTA1 overexpression. However, recent evidences from clinical data raise a critical question on the role of MTA1 in head and neck cancers. This calls for a detailed review to the role of MTA1 in oral cancer. This review gives a brief account on the existing biological and molecular data in the context of head and neck cancer invasion and metastasis in relation to MTA1.

Synergistic effects of combined DNA methyltransferase inhibition and MBD2 depletion on breast cancer cells; MBD2 depletion blocks 5-aza-2'-deoxycytidine-triggered invasiveness

5-Aza-2'-deoxycytidine (5-azaCdR) not only inhibits growth of non-invasive breast cancer cells but also increases their invasiveness through induction of pro-metastatic genes. Methylated DNA binding protein 2 (MBD2) is involved in silencing methylated tumor suppressor genes as well as activation of pro-metastatic genes. In this study, we show that a combination of MBD2 depletion and DNA methyltransferases (DNMT) inhibition in breast cancer cells results in a combined effect in vitro and in vivo, enhancing tumor growth arrest on one hand, while inhibiting invasiveness triggered by 5-azaCdR on the other hand. The combined treatment of MBD2 depletion and 5-azaCdR suppresses and augments distinct gene networks that are induced by DNMT inhibition alone. These data point to a potential new approach in targeting the DNA methylation machinery by combination of MBD2 and DNMT inhibitors.

RECK controls breast cancer metastasis by modulating a convergent, STAT3-dependent neoangiogenic switch

Metastasis is the primary cause of cancer-related death in oncology patients. A comprehensive understanding of the molecular mechanisms that cancer cells usurp to promote metastatic dissemination is critical for the development and implementation of novel diagnostic and treatment strategies. Here we show that the membrane protein RECK (Reversion-inducing cysteine-rich protein with kazal motifs) controls breast cancer metastasis by modulating a novel, non-canonical and convergent signal transducer and activator of transcription factor 3 (STAT3)-dependent angiogenic program. Neoangiogenesis and STAT3 hyperactivation are known to be fundamentally important for metastasis, but the root molecular initiators of these phenotypes are poorly understood. Our study identifies loss of RECK as a critical and previously unknown trigger for these hallmarks of metastasis. Using multiple xenograft mouse models, we comprehensively show that RECK inhibits metastasis, concomitant with a suppression of neoangiogenesis at secondary sites, while leaving primary tumor growth unaffected. Further, with functional genomics and biochemical dissection we demonstrate that RECK controls this angiogenic rheostat through a novel complex with cell surface receptors to regulate STAT3 activation, cytokine signaling, and the induction of both vascular endothelial growth factor and urokinase plasminogen activator. In accordance with these findings, inhibition of STAT3 can rescue this phenotype both in vitro and in vivo. Taken together, our study uncovers, for the first time, that RECK is a novel regulator of multiple well-established and robust mediators of metastasis; thus, RECK is a keystone protein that may be exploited in a clinical setting to target metastatic disease from multiple angles.

Expression of WWOX and FHIT is downregulated by exposure to arsenite in human uroepithelial cells

Ecological studies in Taiwan, Chile, Argentina, Bangladesh, and Mexico have confirmed significant dose-dependent associations between ingestion of arsenic-contaminated drinking water and the risk of various human malignancies. The FHIT and WWOX genes are active in common fragile sites FRA3B and FRA16D, respectively. Reduced expression of FHIT or WWOX is known to be an early indicator of carcinogen-induced cancers. However, the effect of arsenite on the expressions and molecular mechanisms of these markers is still unclear. The aims of this study were (i) to observe the expression of ATR, WWOX and FHIT proteins in urothelial carcinoma (UC) between endemic and non-endemic areas of blackfoot disease (BFD) by immunohistochemical analyses; (ii) to compare expression of these genes between arsenite-treated SV-HUC-1 human epithelial cells and rat uroepithelial cells; and (iii) to determine the role of DNMT and MEK inhibitors on expressions of WWOX and FHIT in response to arsenite in SV-HUC-1. The experiments revealed that expressions of ATR, WWOX and FHIT in UC significantly differed between BFD areas and non-BFD areas (p=0.003, 0.009 and 0.021, respectively). In fact, the results for the arsenite-treated groups showed that ATR, WWOX and FHIT are downregulated by arsenite in SV-HUC-1. However, the inhibitors suppressed the effects of arsenite on WWOX and FHIT proteins and mRNA expression. In conclusion, arsenite decreased expressions of ATR, WWOX and FHIT via ERK1/2 activation in SV-HUC-1 cells. These findings confirm that dysregulations of these markers may contribute to arsenite-induced carcinogenesis.

STAT3 upregulates miR-92a to inhibit RECK expression and to promote invasiveness of lung cancer cells

Background:

Signal transducer and activator of transcription 3 (STAT3) activation is frequently found in human lung cancer and is associated with increased metastasis and reduced survival. How STAT3 enhances invasiveness is unclear.

Methods:

The expression of microRNAs and target genes was measured by real-time RT–PCR. Protein level was studied by western blotting. Luciferase reporter assay was used to confirm the direct targeting of microRNAs. Gelatin zymography was used to study matrix metalloproteinase (MMP) activity. Transwell assay was used to investigate cell migration and invasion.

Results:

Enforced expression of STAT3 decreases the endogenous MMP inhibitor RECK protein but not mRNA level in H460 cells. Conversely, STAT3 inhibitor S3I-201 increases RECK protein in STAT3-activating H1299 cells. We demonstrate that STAT3 upregulates miR-92a to repress RECK via post-transcriptional inhibition. The RECK 3′-untranslated region (3′UTR) reporter activity assay suggests that RECK is a direct repression target of miR-92a. Delivery of pre-miR-92a reduces RECK protein level whereas transfection of anti-miR-92a restores STAT3-induced downregulation of RECK. Anti-miR-92a attenuates MMP activity, migration and invasion of H1299 cells and STAT3-overexpressing H460 cells, suggesting miR-92a is critical for STAT3-induced invasiveness.

Conclusion:

The STAT3-induced miR-92a promotes cancer invasion by suppressing RECK and targeting of the STAT3/miR-92a axis may be helpful for cancer treatment.

Estrogen suppresses expression of the matrix metalloproteinase inhibitor reversion-inducing cysteine-rich protein with Kazal motifs (RECK) within the mouse uterus

RECK (reversion-inducing cysteine-rich protein with Kazal motifs) is a membrane-anchored glycoprotein which regulates MMP2 and MMP9 activity and has been proposed to play a role in embryo implantation while misexpression of RECK has been associated with a variety of carcinomas. Unfortunately, understanding on the steroidal regulation of uterine RECK is lacking. To address this gap in our knowledge, we examined steroidal regulation and cellular expression of Reck mRNA and protein within the mouse uterus in vivo. Uterine Reck mRNA and protein were decreased by estrogen, while progesterone alone had no effect. The estrogen-induced down regulation could be partially blocked by progesterone. RECK was localized primarily to luminal and glandular epithelial cells and the level of expression was regulated in a similar fashion as in whole tissue by the steroids. Knock-down of endogenous RECK in human endometrial epithelial and stromal cells resulted in a significant increase in active MMP9 expression but not that of pro-MMP9 or MMP2. These studies demonstrate that RECK expression in the mouse uterus is steroidally regulated and that within endometrial epithelial and stromal cells, RECK regulates MMP9, but not MMP2 activity.

Reversion-inducing cysteine-rich protein with Kazal motif (RECK) expression: an independent prognostic marker of survival in colorectal cancer

Patient prognosis in colorectal cancer is determined as in most solid cancers by the extent of local invasion and the presence of lymph node and distant metastases. The invasive potential of a tumor depends on the ability to degrade extracellular matrix proteins, for example, by matrix metalloproteinases. An important inhibitor of matrix metalloproteinases is reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a membrane-anchored glycoprotein. This study investigated the prognostic relevance of RECK expression in colorectal cancer in a cohort of 283 patients. Analysis of immunohistochemical tissue microarray data showed that RECK protein levels did not seem to correlate with clinicopathologic parameters (Spearman rank correlation coefficients between -0.14 and -0.18) and that decreased RECK expression was an independent prognostic factor of poor survival, with a mean survival of 70 months in RECK-negative (146 cases) versus 97 months in RECK-positive patients (137 cases) (log-rank test, P = .002).

The silencing of RECK gene is associated with promoter hypermethylation and poor survival in hepatocellular carcinoma

Background: To evaluate the promoter methylation status of RECK gene and mRNA expression in patients with hepatocellular carcinoma (HCC).

Methods: We analyzed RECK methylation by MSP, and RECK mRNA by real-time PCR in 74 HCC. The liver cell lines (7721, Chang and Hep-G2) were treated with 5-Aza-CdR and TSA.

Results: RECK mRNA were lower in HCC tissues (Mean _-∆Ct = -3.29) than that in Non-Hcc tissues (Mean _-∆Ct = -2.42). Expression of RECK was elevated in only 24 (32.43%) of the 74 HCC patients but decreased (-∆∆Ct<0) in 50 (67.57%) of the patients. RECK promoter was hypermethylated in 55.4% (41/74) of HCCs, and in only 17.6% (13/74) of Non-Hcc samples. RECK mRNA were lower in HCC patients with hypermethylation (∆MI>=0.5) (Mean _-∆∆Ct = -1.75) than those with demethylation (∆MI<0.5) (Mean _-∆∆Ct = 0.05), and there is a decreased tendency for RECK mRNA in HCC patients with promoter hypermethylation (p = 0.002). There was a significantly correlation found between RECK mRNA and poor survival after surgery. After treated by 5-Aza-CdR and TSA, we found that RECK mRNA induced different changes in 7721, Chang and Hep-G2 cells. And RECK demethylation also induced by epigenetic inhibitors.

Conclusion: The results suggested that the hypermethylation may lead to promoter silencing of RECK mRNA and associated with poor survival in HCC.

Celecoxib down-regulates RECK expression and up-regulates MMP-2 and MMP-9 expression in human gastric cancer cell line MGC-803

AIM: To explore the antitumor mechanisms of celecoxib by investigating the impact of non-steroidal anti-inflammatory drug (NSAID) celecoxib on the expression of RECK, MMP-2 and MMP-9 in human gastric cancer cell line MGC-803.

METHODS: MGC-803 cells were starved in serum-free medium for 24 h and treated with different concentrations of celecoxib (25, 50, and 100 μg/L) for different durations (12, 24, and 48 h). Cell proliferation was determined by MTT assay. The expression of MMP-9, MMP-2 and RECK mRNAs and proteins was detected by RT-PCR and Western blot, respectively.

RESULTS: Celecoxib inhibited MGC-803 cell proliferation in a concentration-dependent manner at 24 and 48 h but not at 12 h. The inhibitory effect was also time-dependent. Cell proliferation was mostly inhibited after treatment with celecoxib at a concentration of 100 μg/L for 48 h. The expression of RECK, MMP-2 and MMP-9 mRNAs showed no significant differences (all P > 0.05) among cells treated with different concentrations of celecoxib for 12 h. After 12 h, celecoxib increased RECK mRNA expression in a concentration- and time-dependent manner, but decreased the expression of MMP-2 and MMP-9. Similar results were also obtained for RECK, MMP-2 and MMP-9 protein expression.

CONCLUSION: Celecoxib inhibits the proliferation and metastasis of MGC-803 cells possibly via mechanisms associated with up-regulation of RECK expression and down-regulation of MMP-2 and MMP-9 expression.

The chemopreventive properties and therapeutic modulation of green tea polyphenols in oral squamous cell carcinoma

Chemoprevention is a relatively novel and promising approach for controlling cancer that uses specific natural products or synthetic agents to suppress, reverse, or prevent premalignancy before transformation into invasive cancer. Oral cavity squamous cell carcinoma (OCSCC) represents a large, worldwide health burden with approximately 274,000 cases diagnosed annually worldwide. Smoking and alcohol consumption are major inducers of OCSCC. Recently, the human papilloma virus was also shown to potentially be an etiologic factor. Due to its easily identifiable risk factors and the presence of premalignant regions, oral cancer makes a good candidate for chemoprevention. Green tea is the most widely consumed beverage in the world, and it has received considerable attention because of its abundant, scientifically proven, beneficial effects on human health. In this review, we discuss the role of green tea in oral cancer chemoprevention with regard to the multiple molecular mechanisms proposed in various in vitro, in vivo, and clinical trials.

MicroRNA-342 inhibits colorectal cancer cell proliferation and invasion by directly targeting DNA methyltransferase 1

Overexpressed DNA methyltransferase 1 (DNMT1) strongly contributes to tumor suppressor gene silencing in colorectal cancer (CRC). However, the underlying mechanism of DNMT1 overexpression is still unclear. MicroRNAs (miRNA) have been implicated as gene regulators controlling diverse biological processes, including carcinogenesis. In this study, we investigated whether some miRNA is involved in the regulation of DNMT1 and thus play a functional role in CRC. Our results showed that miR-342 was downregulated in CRC tissues and cell lines. Restoration of miR-342 resulted in a dramatic reduction of the expression of DNMT1 at both messenger RNA and protein levels by directly targeting its 3' untranslated region. This in turn reactivated ADAM23, Hint1, RASSF1A and RECK genes via promoter demethylation. Furthermore, the enhanced expression of miR-342 could significantly inhibit SW480 cell proliferation in vitro (P = 0.006). Further investigation demonstrated G(0)/G(1) cell cycle arrest in SW480 cells, which was associated with an upregulation of p21 and downregulation of cyclinE and CDK2. Overexpression of miR-342 also inhibited SW480 cell invasion. The in vivo antitumor effect was evaluated in SW480 cells with lentivirus-mediated expression of miR-342. Results showed that overexpression of miR-342 significantly inhibited tumor growth and lung metastasis in nude mice (P = 0.034). Our findings describe a new mechanism for the regulation of DNMT1 and aberrant DNA hypermethylation in CRC. This is also the first report to demonstrate that miR-342 may act as a tumor suppressor gene in CRC development. The newly identified miR-342/DNMT1 link provides a new, potential therapeutic target for the treatment of CRC.

Downregulation of reversion-inducing-cysteine-rich protein with Kazal motifs (RECK) is associated with enhanced expression of matrix metalloproteinases and cholangiocarcinoma metastases

BACKGROUND

Reversion-inducing-cysteine-rich protein with Kazal motifs (RECK) has been implicated in the attenuation of tumor metastasis by negatively regulating metalloproteinase (MMP) levels. RECK gene expression is downregulated in many solid tumors, with this downregulation being associated with poor prognosis. This study evaluated the role of RECK in cholangiocarcinoma (CCA).

METHODS

The expression of RECK, MMP-2, and MMP-9 in paraffin sections of hamster and human CCA specimens was analyzed by immunohistochemistry. Functional analysis of RECK was performed in RECK small interfering (si) RNA knockdown CCA cell lines. The effect of aspirin on RECK status and function was evaluated using Western blotting, gelatin zymography, invasion and proliferation assays, and PhosphoELISArray analysis of Ras downstream mediators.

RESULTS

Hamster tissues showed high RECK expression in hyperplastic biliary duct epithelia, low RECK expression in precancerous lesions, and no RECK expression in CCA. In human specimens, RECK was highly expressed in normal biliary cells, whereas intrahepatic CCA showed low levels of expression. Downregulation of RECK was correlated with tumor metastasis (P < 0.01) and shorter patient survival (P < 0.02). RECK expression levels were inversely correlated with MMP-2 and MMP-9 expression (P < 0.05). SiRNA RECK-depleted M139 CCA cells exhibited increased MMP-2/-9 gelatinase activities and invasiveness. Aspirin (500 μM) demonstrated myriad effects in human CCA cell lines, including growth suppression, reduced phosphorylation of Akt/Erk/c-Jun, elevation of RECK expression, inhibition of MMP-2/MMP-9 activity, and enhanced invasiveness.

CONCLUSIONS

RECK functions as a metastasis suppressor in CCA; upregulation of RECK expression could provide a potential therapy to improve the prognosis of this type of cancer.

DNA methylation or histone modification status in metastasis and angiogenesis-related genes: a new hypothesis on usage of DNMT inhibitors and S-adenosylmethionine for genome stability

Metastasis is a leading cause of mortality and morbidity in cancer. This process needs angiogenesis. The biology underlying cancer, metastasis, and angiogenesis has been investigated so as to determine the therapeutic targets. Invasive and metastatic cancer cells have undergone numerous genetic and epigenetic changes, manifested by cytoskeletal changes, loss of adhesion, and expression of proteolytic enzymes that degrade the basement membrane. Additionally, in endothelial cells, some epigenetic modifications occur during the formation of angiogenesis. Researchers have used some methylation inhibitors, histone deacetylase inhibitors, or methylating agents (such as S-adenosylmethionine, SAM) against cancer and angiogenesis. Although they are effective to beat these diseases, each one results in differentiation or changes in genome structure. We review epigenetically modified genes related with angiogenesis and metastasis in cancer and endothelial cells, and suggest a new proposal. This hypothesis has discussed the importance of the usage of DNA methylation inhibitors together with SAM to prevent tumor progression and genome instability or changes resulting in additional diseases.

DNA methylation markers in colorectal cancer

Colorectal cancer (CRC) arises as a consequence of the accumulation of genetic and epigenetic alterations in colonic epithelial cells during neoplastic transformation. Epigenetic modifications, particularly DNA methylation in selected gene promoters, are recognized as common molecular alterations in human tumors. Substantial efforts have been made to determine the cause and role of aberrant DNA methylation ("epigenomic instability") in colon carcinogenesis. In the colon, aberrant DNA methylation arises in tumor-adjacent, normal-appearing mucosa. Aberrant methylation also contributes to later stages of colon carcinogenesis through simultaneous methylation in key specific genes that alter specific oncogenic pathways. Hypermethylation of several gene clusters has been termed CpG island methylator phenotype and appears to define a subgroup of colon cancer distinctly characterized by pathological, clinical, and molecular features. DNA methylation of multiple promoters may serve as a biomarker for early detection in stool and blood DNA and as a tool for monitoring patients with CRC. DNA methylation patterns may also be predictors of metastatic or aggressive CRC. Therefore, the aim of this review is to understand DNA methylation as a driving force in colorectal neoplasia and its emerging value as a molecular marker in the clinic.

Role of RECK methylation in gastric cancer and its clinical significance

AIM: To investigate the relation between RECK methylation and clinicopathological characteristics of gastric cancer patients and evaluate the role of RECK methylation in peritoneal metastasis of gastric cancer.

METHODS: Methylation of RECK gene in 40 paired samples of gastric cancer and its corresponding adjacent normal mucosa, lymph nodes and peritoneal irrigation fluid was detected by methylation-specific polymerase chain reaction.

RESULTS: Aberrant methylation of RECK gene was detected in 27.5% (11/40) of the adjacent normal mucosa samples, in 47.5% (19/40) of gastric cancer samples, in 57.1% (12/21) of the lymph node samples, and in 35% (14/40) of peritoneal irrigation fluid samples, respectively, with a significant difference between the adjacent normal mucosa and lymph node samples (P = 0.023). Presence of RECK methylation in the primary tumor samples was significantly correlated with tumor invasion (P = 0.023). The accuracy of RECK methylation in peritoneal lavage fluid samples for the diagnosis of peritoneal metastasis of gastric cancer was 72.5% (26/40), with a sensitivity of 66.7% (6/9) and a specificity of 74.2% (23/31).

CONCLUSION: Aberrant methylation of RECK gene may provide useful information for the early diagnosis and treatment of peritoneal metastasis of gastric cancer.

Density- and serum-dependent regulation of the Reck tumor suppressor in mouse embryo fibroblasts

Reck is a membrane-anchored glycoprotein identified as a transformation suppressor. Accumulating evidence indicates that Reck negatively regulates a wide spectrum of matrix metalloproteinases and is commonly down-regulated in a variety of malignant solid tumors. Physiological cues that regulate Reck expression, however, remained unknown. In this study, we found that Reck expression was up-regulated at high cell density, low serum, or after treatment with some kinase inhibitors, such as PP2 (Src inhibitor), LY294002 (PI3-kinase inhibitor), and PF573228 (FAK inhibitor), in mouse embryo fibroblasts. Curve fitting indicated that the levels of Reck protein and Reck mRNA are quadratic in the cell density. Other factors, including serum, extracellular matrix components (type I collagen and fibronectin), the kinase inhibitors, and some of their oncogenic targets (v-Src and PIK3CA mutants), modify the shape of the quadratic curve. Comparison of these modifications implicated Src in Reck down-regulation under sparse conditions, PI3-kinase in serum-induced Reck down-regulation, and FAK in Reck down-regulation at high cell density. Fibronectin and type I collagen down-regulated Reck, supporting the role of integrin-FAK signaling in Reck down-regulation at high cell density. Our study has revealed multiple signaling pathways impinging on Reck in cultured mouse embryo fibroblasts and sets a foundation for future studies to find effective Reck inducers of potential value in cancer therapy.

Predicting relapse in favorable histology Wilms tumor using gene expression analysis: a report from the Renal Tumor Committee of the Children's Oncology Group

PURPOSE

The past two decades has seen significant improvement in the overall survival of patients with favorable histology Wilms tumor (FHWT); however, this progress has reached a plateau. Further improvements may rely on the ability to better stratify patients by risk of relapse. This study determines the feasibility and potential clinical utility of classifiers of relapse based on global gene expression analysis.

EXPERIMENTAL DESIGN

Two hundred fifty FHWT of all stages enriched for relapses treated on National Wilms Tumor Study-5 passed quality variables and were suitable for analysis using oligonucleotide arrays. Relapse risk stratification used support vector machine; 2- and 10-fold cross-validations were applied.

RESULTS

The number of genes associated with relapse was less than that predicted by chance alone for 106 patients (32 relapses) with stages I and II FHWT treated with chemotherapy, and no further analyses were done. This number was greater than expected by chance for 76 local stage III patients. Cross-validation including an additional 68 local stage III patients (total 144 patients, 53 relapses) showed that classifiers for relapse composed of 50 genes were associated with a median sensitivity of 47% and specificity of 70%.

CONCLUSIONS

This study shows the feasibility and modest accuracy of stratifying local stage III FHWT using a classifier of <50 genes. Validation using an independent patient population is needed. Analysis of genes differentially expressed in relapse patients revealed apoptosis, Wnt signaling, insulin-like growth factor pathway, and epigenetic modification to be mechanisms important in relapse. Potential therapeutic targets include FRAP/MTOR and CD40.

Effects of green tea polyphenol on methylation status of RECK gene and cancer cell invasion in oral squamous cell carcinoma cells

RECK is a novel tumour suppressor gene that negatively regulates matrix metalloproteinases (MMPs) and inhibits tumour invasion, angiogenesis and metastasis. In the present study, we investigated the effects of epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, on the methylation status of the RECK gene and cancer invasion in oral squamous cell carcinoma cell lines. Our results showed that treatment of oral cancer cells with EGCG partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression level of RECK mRNA. Inhibition of MMP-2 and MMP-9 levels was also observed in these cells after treatment with EGCG. Interestingly, EGCG significantly suppressed cancer cell-invasive ability by decreasing the number of invasive foci (P<0.0001) as well as invasion depth (P<0.005) in three-dimensional collagen invasion model. Although further investigation is required to assess the extent of contribution of RECK on MMPs to the suppression of invasive behaviour, these results support the conclusion that EGCG plays a key role in suppressing cell invasion through multiple mechanisms, possibly by demethylation effect on MMP inhibitors such as RECK.

Expression of Reversion-inducing Cysteine-rich Protein with Kazal Motifs in Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus: Links to Disease Activity, Damage Accrual and Matrix Metalloproteinase 9 Secretion

We studied the expression of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) on peripheral blood mononuclear cells (PBMCs), the serum concentration of matrix metalloproteinase 9 (MMP-9) and the MMP-9 secretion ability of PBMCs in patients with systemic lupus erythematosus (SLE), and clinical features were assessed. Compared with PBMCs from healthy donors, PBMCs from SLE patients expressed less RECK protein and mRNA but secreted more MMP-9. The serum concentration of MMP-9 was, however, lower in SLE patients than in healthy donors. The level of RECK protein was inversely associated with the Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI) and MMP-9 secretion in SLE, but no relationship was found between serum MMP-9 concentration and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). In conclusion, the level of RECK protein expressed in PBMCs could be used to predict organ or system damage in SLE and this might help in developing new therapies for SLE targeted at MMP-9.

Expression and biological significance of matrix metalloprofeinase inhibitor RECK gene in esophageal squamous cell carcinoma

AIM: To explore the expression of reversion inducing cysteine rich protein with kazal motifs (RECK) in esophageal squamous cell carcinoma (ESCC) and its correlations with the occurrence and development of ESCC.

METHODS: A total of 62 ESCC specimens, resected in Anyang Tumor Hospital of Henan Province from Februrary 26 to March 16, 2006, were collected. All the cases didn't receive chemotherapy, radiotherapy, and immunotherapy. SP immunohistochemical method and in situ hubridyzation were used to detect the expression of RECK protein and mRNA in the 62 carcinoma specimens, 31 cancer-adjacent specimens (within 3 cm) and 62 normal esophageal epithelial specimens.

RESULTS: The protein and mRNA expression of RECK were closely related with the tumor grades, infilatration and lymphatic metastasis in ESCC. The expression rates of RECK protein were increased ordinally in carcinoma specimens, cancer-adjacent epithelium and normal esophageal epithelial specimens, and there was a significant difference in group comparison (RECK protein: χ² = 10.331, P < 0.01; RECK mRNA: χ² = 19.186, P < 0.01). There was a positive correlation between the protein and mRNA expression of RECK (r = 0.416, P < 0.01) in ESCC.

CONCLUSION: Lower expression of RECK has a correlation with the pathogenesis of and development of ESCC, and RECK may be a new assistant index for early diagnosis and prognosis of ESCC.

Regulation of cell invasion and signalling pathways in the pituitary adenoma cell line, HP-75, by reversion-inducing cysteine-rich protein with kazal motifs (RECK)

Degradation and remodelling of the extracellular matrix has been investigated, with the main focus on the balance between matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP). Recent reports disclose the presence of a novel MMP-inhibiting cell membrane-anchored glycoprotein designated 'reversion-inducing cysteine-rich protein with Kazal motifs' (RECK). Our main aim in this study was to elucidate the role of RECK in cell invasion of pituitary adenomas and its contribution to signal transduction. The function of RECK in cell invasion was investigated by comparing data obtained from full-length RECK clone transfection and gene silencing with RECK mRNA-targeting siRNA. RECK expression was confirmed using real-time RT-PCR and Western blotting. Levels of matrix metalloproteinases (MMP-2 and -9) and TIMP-1 were measured by zymography and reverse zymography, respectively. Cell invasion was examined with a 3-D invasion assay. The signal cascade was investigated by cDNA microarray analysis. As expected, expression of RECK was elevated upon cDNA transfection, and diminished using siRNA. We observed elevation of MMP-2 and -9 expression and consequent 3-D cell invasion in cells under-expressing RECK. However, TIMP expression was not affected by RECK. Analysis with cDNA microarray revealed that RECK additionally upregulates growth hormone-releasing hormone receptor (GHRHR) and latrophilin 2 at the transcriptional level. Our findings collectively suggest that RECK regulates the cell signalling pathway, playing a critical neuroendocrinological role in the pituitary adenoma cell line.

Hypermethylation of the RECK gene predicts poor prognosis in oral squamous cell carcinomas

The RECK gene is a novel tumor suppressor gene that regulates matrix metalloproteinases (MMPs) to inhibit tumor angiogenesis, invasion and metastasis. We investigated the methylation status of the RECK gene in 40 primary oral squamous cell carcinomas (OSCC) and 20 paired adjacent normal mucosa by methylation-specific PCR. Furthermore, we determined the prognostic importance of RECK hypermethylation in OSCC patients. Our findings showed that the RECK gene was methylated in 52.5% (21 of 40) of the primary OSCC. Among the 20 cases with corresponding normal tissues, RECK hypermethylation was detected in both primary tumor (55%, 11 of 20) and adjacent normal mucosa (30%, 6 of 20). Methylation of the RECK gene was not detected in all normal oral mucosa samples of the 12 healthy controls. In univariate analysis, RECK hypermethylation was inversely correlated with recurrence-free survival (p=0.027) and overall survival (p=0.023) of the OSCC patients. Multivariate analysis showed that the methylation status of the RECK gene was the only independent prognostic factor affecting overall survival (p=0.037). The result indicates that hypermethylation of RECK promoter is a common event in human OSCC, occurs concurrently in tumor-adjacent normal mucosa and is correlated with poor prognosis in OSCC patients. Although additional work is needed, hypermethylation of the RECK gene is a promising biomarker in early detection and prognosis for oral cancer patients.

Epigenetic contributions to cancer metastasis

The molecular basis of cancer encompasses both genetic and epigenetic alterations. These epigenetic changes primarily involve global DNA methylation changes in the form of widespread loss of methylation along with concurrent hypermethylation events in gene regulatory regions that can repress tissue-specific gene expression. Increasingly, the importance of these epigenetic changes to the metastatic process is being realized. Cells may acquire an epi-genotype that permits their dissemination from the primary tumour mass or the ability to survive and proliferate at a secondary tissue site. These epigenetic changes may be cancer-type specific, or in some cases may involve a common target gene providing a selective advantage to multiple metastatic cell types. In this review, I examine the growing volume of literature related to the epigenetic contributions to cancer metastasis. I discuss the functional importance of these epigenetic phenomena and how new epigenetic biomarkers may permit the identification of diagnostic signatures of metastasis and the development of new cancer therapies.

Correlation of matrix metalloproteinase suppressor genes RECK, VEGF, and CD105 with angiogenesis and biological behavior in esophageal squamous cell carcinoma

AIM

To explore the expression of reversion inducing cysteine-rich protein with Kazal motifs (RECK), vascular endothelial growth factor (VEGF) and endoglin (CD105) protein and its correlation with occurrence, development, invasion and metastasis in esophageal squamous cell carcinoma (ESCC).

METHODS

Streptavidin-peroxidase (SP) immunohisto-chemistry was used to detect expression of RECK and VEGF in 62 cases of ESCC, 31 cases of adjacent atypical hyperplastic epithelium and 62 cases of normal esophageal epithelium. CD105 Mb was used to assess microvessel density (MVD).

RESULTS

The expression of RECK was closely correlated with histological grade, infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK decreased during cancer development: normal esophageal epithelium (85.5%, 53/62), adjacent atypical hyperplastic epithelium (71.0%, 22/31), and carcinoma (59.7%, 37/62). There was a significant difference among the groups (P < 0.05). The expression of VEGF protein was closely correlated with infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of VEGF protein increased during cancer development: normal esophageal epithelium (29.0%, 18/62), adjacent atypical hyperplastic epithelium (54.8%, 17/31), and carcinoma (67.7%, 42/62). There was a significant difference among the groups (P < 0.05). MVDCD105 increased in accordance with histological grade, but there was no significant difference (grade I, 36.92 +/- 10.85; grade II, 37.65 +/- 9.50; and grade III, 38.06 +/- 12.19). The MVDCD105 was closely correlated with infiltration and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK was inversely correlated with the expression of VEGF and CD105.

CONCLUSION

RECK, VEGF and CD105 play important roles in the infiltration, metastasis and carcinogenesis in esophageal carcinoma. Angiogenesis in ESCC may be promoted by over-expression of CD105.

Correlation of matrix metalloproteinase suppressor genes RECK, VEGF, and CD105 with angiogenesis and biological behavior in esophageal squamous cell carcinoma

AIM

To explore the expression of reversion inducing cysteine-rich protein with Kazal motifs (RECK), vascular endothelial growth factor (VEGF) and endoglin (CD105) protein and its correlation with occurrence, development, invasion and metastasis in esophageal squamous cell carcinoma (ESCC).

METHODS

Streptavidin-peroxidase (SP) immunohisto-chemistry was used to detect expression of RECK and VEGF in 62 cases of ESCC, 31 cases of adjacent atypical hyperplastic epithelium and 62 cases of normal esophageal epithelium. CD105 Mb was used to assess microvessel density (MVD).

RESULTS

The expression of RECK was closely correlated with histological grade, infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK decreased during cancer development: normal esophageal epithelium (85.5%, 53/62), adjacent atypical hyperplastic epithelium (71.0%, 22/31), and carcinoma (59.7%, 37/62). There was a significant difference among the groups (P < 0.05). The expression of VEGF protein was closely correlated with infiltrative depth and lymphatic metastasis in ESCC (P < 0.05). The expression of VEGF protein increased during cancer development: normal esophageal epithelium (29.0%, 18/62), adjacent atypical hyperplastic epithelium (54.8%, 17/31), and carcinoma (67.7%, 42/62). There was a significant difference among the groups (P < 0.05). MVDCD105 increased in accordance with histological grade, but there was no significant difference (grade I, 36.92 +/- 10.85; grade II, 37.65 +/- 9.50; and grade III, 38.06 +/- 12.19). The MVDCD105 was closely correlated with infiltration and lymphatic metastasis in ESCC (P < 0.05). The expression of RECK was inversely correlated with the expression of VEGF and CD105.

CONCLUSION

RECK, VEGF and CD105 play important roles in the infiltration, metastasis and carcinogenesis in esophageal carcinoma. Angiogenesis in ESCC may be promoted by over-expression of CD105.

Recklessness as a hallmark of aggressive cancer

Cancer recurrence after surgical treatment is a major concern for patients and doctors. Understanding what makes tumors prone to recurrence would be an important step toward its prevention. Accumulating evidence indicates that the level of membrane-associated protease regulator reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expressed in tumor tissue is a good prognostic indicator in several common cancers. Certain members of the matrix metalloproteinase family are often upregulated in advanced cancers and are known to play important roles in tumor angiogenesis, invasion and metastasis. RECK negatively regulates several matrix metalloproteinases. Therefore, RECK itself may well be considered a promising tool or target molecule to be activated in cancer therapy. Here we review the recent advances in RECK research and discuss some of the important issues to be addressed in future studies.