Metastasis Suppressor 1 Research Articles

Abstract LB-283: Prognostic significance of BRMS1 promoter methylation in operable breast cancer.

Abstract Introduction: Breast Cancer Metastasis Suppressor-1 (BRMS1) encodes a predominantly nuclear protein that differentially regulates expression of multiple genes, leading to suppression of metastasis without affecting orthotopic tumor growth. We examined the clinical relevance of BRMS1 promoter methylation in early breast cancer. Methods: We analyzed 118 formalin-fixed paraffin embedded samples: 5 pairs of breast tumors and adjacent non-cancerous tissues, 14 non-cancerous tissues, 10 benign fibroadenomas, and 84 primary breast tumors. Peripheral blood mononuclear cells were isolated from 39/84 of these patients and were fixed in cytospins. BRMS1 methylation status was investigated in all FFPE and cytospin stained circulating tumor cells using methylation specific PCR. BRMS1 expression was examined using double-immunofluorescence in isolated PBMC cytospins using anti-BRMS1 and pancytokeratin A45-B/B3 antibodies. Results: BRMS1 promoter methylation was observed in 0/19 noncancerous breast tissues, 0/10 benign fibroadenomas and 31/84(37.8%) breast tumors. During the follow-up period 27/84(32.1%) patients relapsed of which 19/84(22.6%) patients died as a consequence of disease progression. BRMS1 methylation was detected in 15/27(55.6%) patients that relapsed and in 10/19(52.6%) of patients that died. BRMS1 promoter methylation was associated with reduced disease-free interval (P=0.009) while a trend towards a reduced overall survival (OS) was also observed (P=0.071). Expression of BRMS1 on CTC was very heterogeneous: CTC with high BRMS1 expression were found in 7/13(53.8%) CTC positive samples while exclusively CTC with high BRMS1 were found in only 3 patients (23.0%). CTC with low BRMS1 expression were found in 3 patients. CTC negative for BRMS1 were found in 8/13(61.5%) patients. Exclusively CTC with low or negative BRMS1-expression were identified in 6/13(46.1%) patients. 4/13(30.8%) patients had both high and low or negative BRMS1 expression in their CTC. Conclusions: BRMS1 promoter methylation provides important prognostic information for disease free survival in early breast cancer patients. BRMS1 promoter methylation and protein expression were evaluated in primary tumors and corresponding CTC for the first time. BRMS1 expression in CTC was heterogeneous in individual patient samples. CTC expressing epithelial markers but no BRMS1 seem to define a worse prognosis group of patients. These results need to be further evaluated and validated in a larger cohort of breast cancer patients. Citation Format: Maria Chimonidou, Galatea Kallergi, Vasilis Georgoulias, Danny Welch, Evi Lianidou. Prognostic significance of BRMS1 promoter methylation in operable breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-283. doi:10.1158/1538-7445.AM2013-LB-283

Suppression of the proliferation of human U-87 MG glioblastoma cells by new antagonists of growth hormone-releasing hormone in vivo and in vitro

Five-year survival of patients afflicted with glioblastoma multiforme (GBM) is rare, making this cancer one of the most feared malignancies. Previously, we reported that growth hormone-releasing hormone (GHRH) is a potent growth factor in cancers. The present work evaluated the effects of two antagonistic analogs of GHRH (MIA-604 and MIA-690) on the proliferation of U-87 MG GBM tumors, in vivo as well as in vitro. Both analogs were administered subcutaneously and dose-dependently inhibited the growth of tumors transplanted into nude mice (127 animals in seven groups). The analogs also inhibited cell proliferation in vitro, decreased cell size, and promoted apoptotic and autophagic processes. Both antagonists stimulated contact inhibition, as indicated by the expression of the E-cadherin-β-catenin complex and integrins, and decreased the release of humoral regulators of glial growth such as FGF, PDGFβ, and TGFβ, as revealed by genomic or proteomic detection methods. The GHRH analogs downregulated other tumor markers (Jun-proto-oncogene, mitogen-activated protein kinase-1, and melanoma cell adhesion molecule), upregulated tumor suppressors (p53, metastasis suppressor-1, nexin, TNF receptor 1A, BCL-2-associated agonist of cell death, and ifκBα), and inhibited the expression of the regulators of angiogenesis and invasion (angiopoetin-1, VEGF, matrix metallopeptidase-1, S100 calcium binding protein A4, and synuclein-γ). Our findings indicate that GHRH antagonists inhibit growth of GBMs by multiple mechanisms and decrease both tumor cell size and number.

MiR-135a promotes growth and invasion of colorectal cancer via metastasis suppressor 1 <italic>in vitro</italic>

MicroRNAs (miRNAs) are small non-coding RNAs that participate in the spatiotemporal regulation of messenger RNA and protein synthesis. Aberrant miRNA expression leads to developmental abnormalities and diseases. The miR-135a is considered to be oncogenic; however, the functions and mechanisms of miR-135a in colorectal cancer (CRC) are largely unknown. Thus, we investigated the functions and mechanisms of miR-135a, especially its relationship with the metastasis suppressor 1 (MTSS1) gene in CRC. The expression of miR-135a was determined by real-time polymerase chain reaction, while its effect on cell proliferation, migration, and invasion was determined by MTT, without and with matrigel, respectively. The expression of MTSS1 was detected by western blot analysis. It was found that miR-135a expression was higher in human CRC samples than in non-tumor control tissue. Using SW480 and SW620 CRC cell lines, increased proliferation was observed in response to miR-135a. We also demonstrated that miR-135a promoted mobility and invasion via transwell assay with and without Matrigel, respectively, of CRC cells. In contrast, inhibition of miR-135a reduced their proliferative and invasive capability. MTSS1 was identified as a candidate target gene of miR-135a by luciferase report assay. Western blot analysis showed that the expression of MTSS1 was regulated by miR-135a overexpression and knockdown. Similarly, miR-135a-mediated cell mobility and invasion were reduced after MTSS1 was knocked down by small interfering RNA. These data indicated that miR-135a promotes the growth and invasion of CRC cells, at least partially, through targeting MTSS1.

Proteome analysis of actin filament-associated proteins in the postnatal rat cerebellum

The cerebellum contains more neurons than all other brain regions combined and these cells exhibit complex circuit development and dendritic elaboration during the postnatal period. Neural development, cellular morphogenesis, and synaptic plasticity are dependent on the dynamic regulation of the actin cytoskeleton by actin-binding proteins. The identification of the actin filament interactome, including proteins developmentally regulated in the postnatal cerebellum, could help define important regulators of actin cytoskeletal dynamics in developing cerebellar neurons. Affinity purification of cerebellar proteins on F-actin columns, combined with mass spectrometry, in total, 434 actin filament-associated proteins in postnatal rat cerebellum (P7) were identified. Furthermore, semi-quantitative RT-PCR was performed to screening postnatal developmentally regulated genes involved in actin dynamics and membrane trafficking in rat cerebellum (P0–P56). As the result, nine genes encoding members of the cerebellar F-actin interactome were developmentally regulated in the transcriptional level and at least five of them exhibited a similar pattern at the protein expression level by Western blot analysis. Further fluorescent immunohistochemical observations demonstrated that the actin-associated proteins Lethal(2) giant larvae protein homolog 1 (LLGL1) and metastasis suppressor 1 (MTSS1) were specifically upregulated in granule neurons and Purkinje cells during morphogenesis of axons and dendrites. This work defines a provisional actin filament interactome in rat postnatal cerebellum and identifies several candidate proteins that may be involved in the postnatal development of the cerebellum.

Dimerization is necessary for MIM-mediated membrane deformation and endocytosis

MIM [missing in metastasis; also called MTSS1 (metastasis suppressor 1)] is an intracellular protein that binds to actin and cortactin and has an intrinsic capacity to sense and facilitate the formation of protruded membranous curvatures implicated in cellular polarization, mobilization and endocytosis. The N-terminal 250 amino acids of MIM undergo homodimerization and form a structural module with the characteristic of an I-BAR [inverse BAR (Bin/amphiphysin/Rvs)] domain. To discern the role of the dimeric configuration in the function of MIM, we designed several peptides able to interfere with MIM dimerization in a manner dependent upon their lengths. Overexpression of one of the peptides effectively abolished MIM-mediated membrane protrusions and transferrin uptake. However, a peptide with a high potency inhibiting MIM dimerization failed to affect its binding to actin and cortactin. Thus the results of the present study indicate that the dimeric configuration is essential for MIM-mediated membrane remodelling and serves as a proper target to develop antagonists specifically against an I-BAR-domain-containing protein.

MicroRNA-182 downregulates metastasis suppressor 1 and contributes to metastasis of hepatocellular carcinoma

BackgroundmiR-182 is one of the most significantly up-regulated miRNAs in hepatocellular carcinoma (HCC). Metastasis suppressor 1 (MTSS1), one target gene of miR-182, plays an important role in the metastasis of cancers. However, it remains unclear what role does function and mechanism of miR-182 and MTSS1play in HCC.MethodsmiR-182 expression was tested in 86 cases of paired HCC and normal tissues by real-time PCR and the relationships between miR-182 expression and clinicopathological parameters were analyzed. The expression of MTSS1 was evaluated by immunohistochemistry and western blot in the above tissues and its correlation with miR-182 expression was analyzed. Moreover, western blot and invasion assays were performed after transfection of pre-miR-182 or anti-miR-182 to HCC cell lines. In addition, luciferase assays was performed to confirm the regulation of miR-182 on MTSS1.ResultsCompared with normal tissue, miR-182 was up-regulated and MTSS1 was down-regulated in HCC tissues. Moreover, the over-expression of miR-182 was correlated with intrahepatic metastasis (p = 0.034) and poor prognosis (p = 0.039) of HCC patients. There was a negative correlation between miR-182 and MTSS1 expression in both HCC tissues (r = −0.673, p < 0.01) and HCC cell lines (r = −0.931, p = 0.021). Furthermore, the up-regulation of miR-182 resulted in the down-regulation of MTSS1 and increased invasive potential of HUH-1, and reverse results were also confirmed when the expression of miR-182 was inhibited. In addition, the results of the luciferase assay demonstrated the targeted regulation of miR-182 on MTSS1.ConclusionsmiR-182 could promote metastasis of HCC and inhibit the expression of MTSS1. miR-182 and MTSS1 are potential prognostic markers and/or therapeutic targets in HCC.

MiR-23a Promotes the Transition from Indolent to Invasive Colorectal Cancer

Colorectal cancer is a classic example of a tumor that progresses through multiple distinct stages in its evolution. To understand the mechanisms regulating the transition from indolent to invasive disease, we profiled somatic copy number alterations in noninvasive adenomas and invasive adenocarcinomas from Apc and DNA mismatch repair (MMR) mutant mouse models. We identified a recurrent amplicon on mouse chromosome 8 that encodes microRNA (miRNA) 23a and -27a (miR). miR-23a and -27a levels are upregulated in mouse intestinal adenocarcinomas, primary tumors from patients with stage I/II colorectal cancers, as well as in human colorectal cancer cell lines and cancer stem cells. Functionally, miR-23a promotes the migration and invasion of colorectal cancer cells and stem cells, whereas miR-27a primarily promotes proliferation. We computationally and experimentally validated that metastasis suppressor 1 (MTSS1) is a direct miR-23a target and similarly validated that the ubiquitin ligase FBXW7 is a direct miR-27a target. Analyses of computationally predicted target genes in microarray data sets of patients with colorectal cancers are consistent with a role for miR-23a, but not miR-27a, specifically in invasive colorectal cancers.

MiR‐182 overexpression in tumourigenesis of high‐grade serous ovarian carcinoma

Molecular pathogenesis of high-grade serous ovarian carcinoma (HG-SOC) is poorly understood. Recent recognition of HG-SOC precursor lesions, defined as serous tubal intraepithelial carcinoma (STIC) in fimbria, provides a new venue for the study of early genetic changes in HG-SOC. Using microRNA profiling analysis, we found that miR-182 expression was significantly higher in STIC than in matched normal Fallopian tube. Further study revealed that miR-182 was significantly overexpressed in most HG-SOC cases. To test whether miR-182 plays a major role in early tumourigenesis of HG-SOC, we overexpressed miR-182 in immortalized ovarian surface, Fallopian tube secretory cells and malignant ovarian cell lines, and found that miR-182 overexpression resulted in increased tumour transformation in vitro, and enhanced tumour invasiveness in vitro and metastasis in vivo. Mechanistically, we demonstrated that the oncogenic properties of miR-182 in ovarian cancer were mediated in part by its impaired repair of DNA double-strand breaks and negative regulation of breast cancer 1 (BRCA1) and metastasis suppressor 1 (MTSS1) expression as well as its positive regulation of the oncogene high-mobility group AT-hook 2 (HMGA2). Our findings suggest that miR-182 dysregulation confers powerful oncogenic potential in the tumourigenesis of HG-SOC. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract 133: MiR-182 overexpression and ovarian high grade serous carcinoma

Abstract OBJECTIVES: BRCA1/BRCA2 mutations are hallmarks high grade papillary serous carcinoma (H-PSC). This correlation is due to the fact that approximately 40-50% of H-PSC have altered expression of BRCA1/BRCA2 (including germline and somatic mutations and epigenetic modifications). Furthermore, women with germline mutations of BRCA1/2 have a 30%-70% chance of developing H-PSC by the age of 70. If inactivation of BRCA1/2 is critical in the early tumorigenesis of H-PSC, there must be other mechanisms whereby BRCA1/2 is downregulated in the remaining 50% of H-PSC. Recent findings of miR-182-mediated repression of BRCA1 expression and significant overexpression of miR-182 in H-PSC suggest that miR-182 may play an important role in the tumorigenesis of H-PSC through its negative regulation of BRCA1. DESIGNS: To explore the role of miR-182 through the negative regulation of BRCA1 in the early stages of H-PSC tumorigenesis, we conducted in vitro molecular and cellular analyses of miR-182 in human fallopian tube secretory (FTSE) and ovarian surface epithelia (OSE) cell lines. We 1) established stable cell lines with stable miR-182 overexpression; 2) examined the oncogenic properties of miR-182 by anchorage-independent growth, cell proliferation and invasion in vitro; 3) investigated DNA damage response in cells with miR-182 expression after ionizing radiation (IR); 4) examined and characterized several predicted target genes of miR-182, including BRCA1, HMGA2 and MTSS1; 5) studied tumor growth and metastasis in vivo (in nude mice) with and without miR-182 overexpression. RESULTS: 1) Introducing miR-182 overexpression in normal immortalized cell lines (both FTSE and OSE) resulted in tumor transformation and significantly enhanced cell invasion in vitro. 2) FTSE and OSE cell lines with miR-182 overexpression had impaired repair of DNA double-strand breaks when treated with low doses of IR. 3) We further demonstrated that the oncogenic properties of miR-182 in ovarian cancer were mediated by its negative regulation of breast cancer 1 (BRCA1) and metastasis suppressor 1 (MTSS1) expression and its positive regulation of oncogene high-mobility group AT-hook 2 (HMGA2). Knockdown of miR-182 expression in ovarian cancer cell lines (SKOV3, and HEY) could therefore partially restore BRCA1 and MTSS1 expression and reduce aggressive tumor growth in vitro. Ovarian cancer cell line SKOV3 with miR-182 overexpression enhances lung metastasis in vivo. CONCLUSION: MiR-182 confers a powerful oncogenic potential in normal and malignant ovarian/fallopian tube cell lines through its negative regulation of several critical target genes in H-PSC, including BRCA1, MTSS1 and HMGA2. Therefore, MiR-182 likely plays a significant role in the early tumorigenesis of H-PSC. Our findings provide a novel target and a new potential therapeutic modality in treating H-PSC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 133. doi:1538-7445.AM2012-133

Mtss1 Promotes Cell-Cell Junction Assembly and Stability through the Small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis.

Expression and clinical significance of miR-23a and metastasis suppressor 1 in colon carcinoma

To investigate the expression of miR-23a and metastasis suppressor 1 (MTSS1) and their clinical significance in colon carcinoma. A total of 92 cases of colon carcinomas were collected with both the tumor and paired normal tissue samples for the study. The miR-23a targeting MTSS1 was evaluated by luciferase reporter vector. Cell invasion potential was evaluated by trans-well invasion assay. In-situ hybridization and immunohistochemistry were used to detect miR-23a and MTSS1 expression. MiR-23a downregulated the expression of MTSS protein and enhanced the invasiveness of colon carcinoma. The expression rates of miR-23a and MTSS1 were 87.0% (80/92) and 17.4% (16/92) in colon carcinoma cases, respectively (P < 0.01). The up-regulation of miR-23a expression was associated with an advanced clinical stage (P = 0.029) and depth of invasion (P = 0.000). The expression of miR-23a was higher in the tumors with lymph node metastasis than those without (P = 0.041). Down-regulation of MTSS1 expression was associated with an advanced clinical stage (P = 0.027) and depth of invasion (P = 0.017). The expression of MTSS1 was lower in the tumors with lymph node metastasis than those without (P = 0.009). The expression of miR-23a had significantly negative correlation with that of MTSS1 (r = -0.594, P = 0.013). MiR-23a expression promotes colon carcinoma cell growth, invasion and metastasis through inhibition of MTSS gene. Both the low expression of MTSS1 and high expression of miR-23a may serve as important biological markers for the malignant phenotypes of colon cancer, such as invasion and metastasis.

Fascin is a key regulator of breast cancer invasion that acts via the modification of metastasis-associated molecules.

The actin-bundling protein, fascin, is a member of the cytoskeletal protein family that has restricted expression in specialized normal cells. However, many studies have reported the induction of this protein in various transformed cells including breast cancer cells. While the role of fascin in the regulation of breast cancer cell migration has been previously shown, the underlying molecular mechanism remained poorly defined. We have used variety of immunological and functional assays to study whether fascin regulates breast cancer metastasis-associated molecules. In this report we found a direct relationship between fascin expression in breast cancer patients and; metastasis and shorter disease-free survival. Most importantly, in vitro interference with fascin expression by loss or gain of function demonstrates a central role for this protein in regulating the cell morphology, migration and invasion potential. Our results show that fascin regulation of invasion is mediated via modulating several metastasis-associated genes. We show for the first time that fascin down-regulates the expression and nuclear translocation of a key metastasis suppressor protein known as breast cancer metastasis suppressor-1 (BRMS1). In addition, fascin up-regulates NF-kappa B activity, which is essential for metastasis. Importantly, fascin up-regulates other proteins that are known to be critical for the execution of metastasis such as urokinase-type plasminogen activator (uPA) and the matrix metalloproteases (MMP)-2 and MMP-9. This study demonstrates that fascin expression in breast cancer cells establishes a gene expression profile consistent with metastatic tumors and offers a potential therapeutic intervention in metastatic breast cancer treatment through fascin targeting.

Expressions of breast cancer metastasis suppressor-1 and heparanase in primary hepatocellular carcinoma and chronic liver diseases and the clinicopathological significances

乳腺癌转移抑制基因1 (BRMS1)可通过多种途径发挥抑制恶性肿瘤转移的作用,淋巴结转移和(或)远端血道转移患者BRMS1多呈低表达或失表达,且与这些恶性肿瘤预后密切相关[1-3].近年研究证实,乙酰肝素酶(HPA)表达水平与多种恶性肿瘤的侵袭、转移和预后密切相关,高水平表达者癌细胞侵袭潜能力强、易发生转移且预后差.本研究检测了慢性肝病肝组织、原发性肝细胞癌(HCC)组织及其癌旁组织中BRMS1和HPA表达水平并探讨其临床病理意义. 关键词：癌,肝细胞;基因,肿瘤抑制;肝素裂解酶;肝病,慢性

MTSS1, a novel target of DNA methyltransferase 3B, functions as a tumor suppressor in hepatocellular carcinoma

DNA methyltransferase 3B (DNMT3B) mediates gene silencing via epigenetic mechanisms during hepatocellular carcinoma (HCC) progression. We aimed to identify novel targets of DNMT3B and their potential regulatory mechanisms in HCC. Metastasis suppressor 1 (MTSS1) was one of the DNMT3B targets and selected for further study. DNMT3B overexpression was detected in 81.25% of clinical HCC specimens and was negatively associated with MTSS1 in HCC cells and clinical samples. The underlying mechanism by which DNMT3B silences MTSS1 was studied using a combination of methylation-specific polymerase chain reaction (PCR) and bisulfite genome sequencing, chromatin immunoprecipitation-PCR and luciferase reporter assays. We found that the MTSS1 promoter region was sparsely methylated, and the methylation inhibitors failed to abolish DNMT3B-mediated MTSS1 silencing. DNMT3B protein bound directly to the 5'-flanking region (-865/-645) of the MTSS1 gene to inhibit its transcription. The functional role of MTSS1 was investigated using in vitro and in vivo tumorigenicity assays. As a result, MTSS1 exerted tumor suppressor effects and arrested cells in the G2/M phase, but not the G1/S phase of the cell cycle when it was depleted or overexpressed in HCC cells. Taken together, MTSS1, a novel target of DNMT3B, is repressed by DNMT3B via a DNA methylation-independent mechanism. MTSS1 was further characterized as a novel tumor suppressor gene in HCC. These findings highlight how DNMT3B regulates MTSS1, and such data may be useful for the development of new treatment options for HCC.

New Approaches to Molecular Diagnostics of Prenatal Pathology

Analysis of the spectrum of amniotic fluid proteins in physiological and abnormal pregnancy using proteomic analysis allowed detection of a number of difference proteins, that are absent or, alternatively, appear in gestosis. Among absent proteins, there were NADPH-dependent carbonyl reductase, epidermal fatty acid-binding protein, haptoglobin, calgranulins A and B. In contrast to proteomic spectrum of amniotic fluid in physiological pregnancy, 7 new proteins appear during gestosis, 3 of them were identified: C area of immunoglobulin K-chain, breast cancer metastasis suppressor-1, and protein-1 containing AIG2-like domain. Possible effects of revealed differences in proteomic spectrum on development of main disturbances during gestosis are discussed. Difference proteins detected in amniotic fluid may serve as gestosis markers.

MicroRNA-135a contributes to the development of portal vein tumor thrombus by promoting metastasis in hepatocellular carcinoma

Portal vein tumor thrombus (PVTT) has previously been demonstrated to correlate with poor prognosis of hepatocellular carcinoma. Approximately 50-80% of HCC is accompanied by portal or hepatic vein invasion. The underlying mechanisms of PVTT development remain unclear. This study aimed to elucidate the role of miR-135a in PVTT tumorigenesis. In the present study, we investigated the expression of microRNAs and mRNAs in PVTT tissues using advanced microRNA and cDNA microarray techniques. MicroRNA (miR)-135a was noted to be highly over-expressed in PVTT and the cell line CSQT-2 and was selected for further study. We characterized the function of miR-135a in vitro and in vivo. We also analyzed the clinical relevance of miR-135a in relation to the prognosis and survival of HCC patients with PVTT. Our analyses found that the miRNA and mRNA expression profiles of PVTT were distinct from the parenchyma tumor. Overexpression of miR-135a favors invasive and metastatic behavior in vitro. Furthermore, in a CSQT-2 orthotopic transplantation nude mouse model, blockade of miR-135a significantly reduced PVTT incidence. We also found that miR-135a was transcribed by forkhead box M1 (FOXM1), and metastasis suppressor 1 (MTSS1) was identified as the direct and functional target of miR-135a. Additionally, the cohort analysis revealed the relevance of miR-135a with respect to the prognosis and survival of HCC patients with PVTT. Our data suggest an important role for miR-135a in promoting PVTT tumorigenesis and indicate the potential application of miR-135a in PVTT therapy.

The impact of Metastasis Suppressor-1, MTSS1, on oesophageal squamous cell carcinoma and its clinical significance

BackgroundMetastasis suppressor-1 (MTSS1) has been proposed to function as a cytoskeletal protein with a role in cancer metastasis. Recent studies have demonstrated the clinical significance of MTSS1 in certain type of cancers, yet the clinical relevance of MTSS1 in oesophageal squamous cell carcinoma (ESCC) has not been reported.MethodsIn this study, we assessed the expression levels of MTSS1 in tumours and its matched adjacent non-tumour tissues obtained from 105 ESCC patients. We also used ESCC cells with differing MTSS1 expression and assessed the influence of MTSS1 on ESCC cells.ResultsDown-regulation of MTSS1 expression was observed both in oesophageal tumour tissues and ESCC cancer cell lines. We also reported that MTSS1 expression was associated with tumour grade (p = 0.024), lymph node metastasis (p = 0.010) and overall survival (p = 0.035). Patients with high levels of MTSS1 transcripts had a favorable prognosis in comparison with those who had reduced or absent expression levels. Using over-expression and knockdown approach, we created sublines from ESCC cells and further demonstrated that MTSS1 expression in ESCC cells significantly influenced the aggressiveness of the oesophageal cancer cells, by reducing their cellular migration and in vitro invasiveness.ConclusionMTSS1 serves as a potential prognostic indicator in human ESCC and may be an important target for cancer therapy.

MTSS1 Overexpression Correlates with Poor Prognosis in Colorectal Cancer

BackgroundThe aims of this study were to investigate metastasis suppressor 1 (MTSS1) expression in benign and malignant colorectal tissues and to explore its significance in the prognosis of colorectal cancer (CRC) patients. MethodsMTSS1 expression was detected by immunohistochemistry in CRC, colorectal adenomatous polyp (precancerous lesion) and normal colorectal tissues. The relationship between MTSS1 expression in CRC tissues and clinicopathologic factors was analyzed with Mann–Whitney U test. MTSS1 protein expression was observed by Western blot in CRC tissues and adjacent nontumor colorectal tissues. Two factors between MTSS1 expression and CRC patient tumor node metastasis (TNM) stage were analyzed by Spearman rank correlation analysis. The Kaplan–Meier method and log-rank test were employed to compare the overall survival between MTSS1 negative/weak positive expression group and MTSS1 strong positive expression group. ResultsMTSS1 expression rates were significantly higher in CRC tissues (99 out of 135, 73.30%) than that in normal colorectal tissues (one out of seven, 14.29%), nontumor colorectal tissues (six out of 32, 18.75%), and adenomatous polyp tissues (four out of 15, 26.67%; P = 0.003, P < 0.001, P = 0.001, respectively). The upregulated MTSS1 expression in CRC tissues was significantly correlated to poor differentiation (P = 0.005), tissue invasion (P = 0.018), high preoperative CEA level (P = 0.022), present lymph node metastasis (P = 0.003), and high TNM stage (P = 0.002). MTSS1 expression was positively correlated with clinical TNM stage, that suggested the more advanced clinical TNM stage corresponding to the higher expression level of MTSS1 (rs = 0.327, P < 0.05). Western blotting demonstrated that MTSS1 expression was upregulated in 25 of 32 CRC tissues (75.0%) compared to corresponding adjacent nontumor colorectal tissues. The overall 5-year survival of MTSS1 strong positive expression CRC patients was significantly shorter than that of MTSS1 negative and weakly positive expression group. In multivariate analysis, MTSS1 expression maintained independent prognostic influence on overall survival (P = 0.004). ConclusionMTSS1 may be a good biomarker to be applied in the clinical setting to predict the prognosis of CRC patients with completely resected.

5-Aza-2'-deoxycytidine inhibiting metastasis to lungs of triple-negative breast cancer cells

Objective To investigate the effect of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on metastasis to lungs of triple-negative breast cancer (TNBC) MDA-MB-231 cells and the mechanisms. Methods MDA-MB-231 cells were divided into two groups: control group and 5-Aza-CdR-treated group. The mRNA expression and promoter methylation status of breast cancer metastasis suppressor-1 (BRMS1 ) and CXC chemokine receptor-4 (CXCR4) in the MDA-MB-231 cells were evaluated by semi-quantitative reverse transcription-polymerase chain reaction ( SqRT-PCR) and methylation specific polymerase chain reaction (MSP) respectively. Then 2 x 105 cells were injected into each BALB/C nu/nu mouse (5 mice in each group) through lateral tail veins. Five weeks later, the metastasis of lungs was evaluated through the mRNA abundance of the target gene HPRT in the lungs tissue from the mice detected by fluorescent quantitative RT-PCR (FqRT-PCR). Results 5-Aza-CdR up-regulated the BRMS1 mRNA expression [0 versus 0. 390 ±0. 001 (relative integrated density value, IDV against GAPDH) ,P ＜0. 05] and demethylated the methylated CpG island B in promoter, while the CXCR4 mRNA expression (0. 580 ±0. 003 versus 0. 580 ±0. 010,P＞0. 05) and the status of unmethylated CXCR4 CpG island 1 in promoter had no significant change. The Ct values of HPRT and GAPDH in control and 5-Aza-CdR-treated groups were 24. 75 ± 1. 55,16. 19 ±0. 69 versus 27. 61 ± 1. 67, 17. 48 ±0. 96 respectively, 2-△△Ct =0. 34, and the inhibitory rate of metastasis was 66% . The mRNA abundance of the HPRT was lower and there were fewer metastases in the lungs of 5-Aza-CdR-treated group than in control group. Conclusion 5-Aza-CdR reactivated tumor metastasis suppressor gene BRMS1 and decreased the metastasis to lungs of TNBC MDA-MB-231 cells by demethylation mechanism. Key words: 5-Aza-CdR; Methylation; Breast carcinoma; Metastasis

MTSS1 a multifunctional protein and its role in cancer invasion and metastasis

MTSS1 (metastasis suppressor-1) was first identified as a metastasis suppressor missing in metastatic bladder carcinoma cell lines. The down-regulation of MTSS1 that may be caused by DNA methylation was also observed in many other types of cancer. While accumlating evidence for the function of MTSS1 support the concept that it is unlikely to be a metastasis suppressor, but actually acts as a scaffold protein that interacts with multiple partners to regulate actin dynamics. It has also been demonstrated that MTSS1 is involved in the Shh signaling pathway in the developing hair follicle and in basal cell carcinomas of the skin. Such evidence indicates that MTSS1 as a multiple functional molecular player and has an important role in development, carcinogenesis and metastasis. However, the biochemical mechanisms by which MTSS1 functions in cells and the physiological role of this protein in animals remain largely unknown. In this review, we will discuss the current knowledge of MTSS1's role in cancer metastasis, carcinogenesis, and development. The clinical significance of MTSS1 will also be discussed.