92140

MTDH

metadherin;MTDH;metadherin

3D3/LYRIC|astrocyte elevated gene 1|astrocyte elevated gene-1 protein|lysine-rich CEACAM1 co-isolated protein|metastasis adhesion protein|protein LYRIC

8q22.1

protein-coding

We used a phage expression library of cDNAs from metastatic breast carcinoma to identify protein domains that bind to the vasculature of the lung, a frequent site of breast cancer metastasis. We found that one protein domain selectively targeted phage as well as cells to the lung. This domain is part of the protein metadherin, shown by gene expression profiling to be overexpressed in metastatic breast cancer. Immunostaining revealed that metadherin is overexpressed in breast cancer tissue and breast tumor xenografts. Antibodies reactive to the lung-homing domain of metadherin and siRNA-mediated knockdown of metadherin expression in breast cancer cells inhibited experimental lung metastasis, indicating that tumor cell metadherin mediates localization at the metastatic site.

Targeted therapy for metastatic diseases relies on the identification of functionally important metastasis genes from a large number of random genetic alterations. Here we use a computational algorithm to map minimal recurrent genomic alterations associated with poor-prognosis breast cancer. 8q22 genomic gain was identified by this approach and validated in an extensive collection of breast tumor samples. Regional gain of 8q22 elevates expression of the metastasis gene metadherin (MTDH), which is overexpressed in more than 40% of breast cancers and is associated with poor clinical outcomes. Functional characterization of MTDH revealed its dual role in promoting metastatic seeding and enhancing chemoresistance. These findings establish MTDH as an important therapeutic target for simultaneously enhancing chemotherapy efficacy and reducing metastasis risk.

Accumulating data have shown the involvement of microRNAs in cancerous processes as either oncogenes or tumor suppressor genes. Here, we established miR-30a as a tumor suppressor gene in breast cancer development and metastasis. Ectopic expression of miR-30a in breast cancer cell lines resulted in the suppression of cell growth and metastasis in vitro. Consistently, the xenograft mouse model also unveiled the suppressive effects of miR-30a on tumor growth and distal pulmonary metastasis. With dual luciferase reporter assay, we revealed that miR-30a could bind to the 3'-untranslated region of metadherin (MTDH) gene, thus exerting inhibitory effect on MTDH. Furthermore, we demonstrated that silence of MTDH could recapitulate the effects of miR-30a overexpression, while overexpression of MTDH could partially abrogate miR-30a-mediated suppression. Of significance, expression level of miR-30a was found to be significantly lower in primary breast cancer tissues than in the paired normal tissues. Further evaluation verified that miR-30a was negatively correlated with the extent of lymph node and lung metastasis in patients with breast cancer. Taken together, our findings indicated miR-30a inhibits breast cancer proliferation and metastasis by directly targeting MTDH, and miR-30a can serve as a prognostic marker for breast cancer. Manipulation of miR-30a may provide a promising therapeutic strategy for breast cancer treatment.

The aim of the study was to investigate the role of AEG-1 in colorectal cancer and the relationship between AEG-1 protein expression and pathological characteristics and prognosis in colorectal cancer. The AEG-1 mRNA and protein expression level between the tumor cells from the cases with liver metastasis and those from the ones without live metastasis were detected by RT-PCR and immunohistochemistry staining. The relationship between AEG-1 and clinicopathological parameters of colorectal cancer was determined. AEG-1 expressed positively in 218 (41.92%) of the 520 cases examined. It showed that both mRNA and protein level AEG-1 were over-expressed in the cases with liver metastasis compared with those without liver metastasis (P=0.01). After immunohistochemistry analysis, the expression of AEG-1 protein was related to age, Dukes stage and distant metastasis (P=0.001, 0.001 and 0.016, respectively). After survival analysis, the cases with highly expressed AEG-1 protein attained a significantly poorer postoperative disease-specific survival than those with none/low-expressed AEG-1 protein (P=0.001). In the Cox regression test, histological grade, Dukes stage and AEG-1 were detected as the independent prognostic factors (P=0.035, 0.001 and 0.010, respectively). AEG-1 protein may be a potential new early liver metastasis biomarker of colorectal cancer.

The molecular mechanism underlying the invasiveness of colorectal cancer (CRC) cells remains largely unknown. Here, we found that astrocyte elevated gene-1 (AEG-1) was significantly upregulated in CRC tissues, compared with the adjacent normal tissues from human patients. Ectopic expression of AEG-1 enhanced the invasive ability of CRC cells, while small interfering RNA (siRNA)-induced knockdown of AEG-1 inhibited the invasive ability of CRC cells. Transcription, protein levels, and secretion of matrix metalloproteinase 9 (MMP9), all increased by AEG-1 overexpression in CRC cells, and all decreased by AEG-1 inhibition. Suppression of endogenous MMP9 abrogated the effects of AEG-1 on invasiveness, without affecting AEG-1 levels. Taken together, these findings suggest that AEG-1 contributes to CRC invasiveness and metastasis by enhancing MMP9 activity. Thus, AEG-1 appears to be a novel therapeutic target for preventing the metastasis of CRC.

PURPOSE: To investigate the expression of metadherin (MTDH) for its prognostic value in hepatocellular carcinoma (HCC) and its role in promoting HCC metastasis. EXPERIMENTAL DESIGN: This study employed a tissue microarray containing samples from 323 HCC patients to examine the expression of MTDH and its correlation with other clinicopathologic characteristics. The role of MTDH in the regulation of HCC metastasis was investigated both in vitro and in vivo using short hairpin RNA (shRNA)-mediated downregulation of MTDH in HCC cell lines with various metastatic potentials. RESULTS: The expression of MTDH was markedly higher in HCC tumors than in normal liver tissue. Particularly high MTDH expression was observed in tumors with microvascular invasion, pathologic satellites, poor differentiation, or tumor-node-metastasis stages II to III. Furthermore, the clinical outcome was consistently poorer for the MTDH(high) group than for the MTDH(low) group in the 1-, 3-, and 5-year overall survival (OS) rates and in the 1-, 3-, 5-year cumulative recurrence rates. In a nude mice model, the shRNA-mediated downregulation of MTDH resulted in a reduced migratory capacity in HCC cell lines, as well as a reduction in pulmonary and abdominal metastasis. Furthermore, we found that the expression level of MTDH correlated with four epithelial-mesenchymal transition (EMT) markers. Knockdown of MTDH expression in HCC cell lines resulted in downregulation of N-cadherin and snail, upregulation of E-cadherin, and translocation of beta-catenin. CONCLUSIONS: MTDH may promote HCC metastasis through the induction of EMT process and may be a candidate biomarker for prognosis as well as a target for therapy.

metastasis contributes to the poor prognosis of hepatocellular carcinoma (HCC). However, the mechanism through which a primary HCC cell develops into a metastatic phenotype is not well understood. The purpose of this study was to examine the correlation between metadherin (MTDH)/astrocyte elevated gene-1 (AEG-1) expression in HCC cell lines of different metastatic potentials and such metastatic phenotypes as orientation chemotaxis and adhesion. MTDH/AEG-1 expression was detected by RT-PCR and western blotting in HCC cell lines (HepG2, Huh7, Sk-HEP-1, MHCC-97H). Distribution of MTDH/AEG-1 was observed by immunofluorescence staining and confocal laser scanning microscopy. The abilities of orientation chemotaxis and adhesion and the index of interaction between HCC cell lines and microvascular endothelial cell lines (MVECs, including HUVECs and HPMECs) were measured by chemotaxis assay and adhesion assay, respectively. The results showed that MTDH/AEG-1 protein expression was significantly higher in high metastatic potential cancer cell lines (Sk-HEP-1, MHCC-97H) than in low metastatic potential cell lines (HepG2, Huh7) (P<0.05). The MTDH/AEG-1 protein was localized in the perinuclear region of HCC cells. Furthermore, the abilities of orientation chemotaxis and adhesion of HCC cells to HPMECs were increased as compared with those of HCC cells to HUVECs (P<0.05). The abilities of orientation chemotaxis and adhesion were much stronger in Sk-HEP-1 and MHCC-97H cells with MTDH/AEG-1 highly expressed than in HepG2 and Huh7 cells with MTDH/AEG-1 lowly expressed (P<0.05). These results suggested that the expression of MTDH/AEG-1 gene in HCC cell lines of different metastatic potentials was closely positively related to the abilities of orientation chemotaxis and adhesion of HCC cells. It was deduced that MTDH/AEG-1 might play a pivotal role in the lung-specific metastasis of HCC, which may be mediated through orientation chemotaxis and adhesion abilities of HCC cells. MTDH/AEG-1 may serve as a potential therapeutic target for HCC.

tumor progression and metastasis are complex processes involving intricate interplay among multiple gene products. Astrocyte elevated gene (AEG)-1 was cloned as an human immunodeficiency virus (HIV)-1-inducible and tumor necrosis factor-alpha (TNF-alpha)-inducible transcript in primary human fetal astrocytes (PHFA) by a rapid subtraction hybridization approach. AEG-1 down-regulates the expression of the glutamate transporter EAAT2; thus, it is implicated in glutamate-induced excitotoxic damage to neurons as evident in HIV-associated neurodegeneration. Interestingly, AEG-1 expression is elevated in subsets of breast cancer, glioblastoma multiforme and melanoma cells, and AEG-1 cooperates with Ha-ras to augment the transformed phenotype of normal immortal cells. Moreover, AEG-1 is overexpressed in >95% of human malignant glioma samples when compared with normal human brain. Overexpression of AEG-1 increases and siRNA inhibition of AEG-1 decreases migration and invasion of human glioma cells, respectively. AEG-1 contains a lung-homing domain facilitating breast tumor metastasis to lungs. These findings indicate that AEG-1 might play a pivotal role in the pathogenesis, progression and metastasis of diverse cancers. Our recent observations indicate that AEG-1 exerts its effects by activating the nuclear factor kappa B (NF-kappaB) pathway and AEG-1 is a downstream target of Ha-ras and plays an important role in Ha-ras-mediated tumorigenesis. These provocative findings are intensifying interest in AEG-1 as a crucial regulator of tumor progression and metastasis and as a potential mediator of neurodegeneration. In this review, we discuss the cloning, structure and function(s) of AEG-1 and provide recent insights into the diverse actions and intriguing properties of this molecule.

metastasis is the deadliest and most poorly understood feature of malignant diseases. Recent work has shown that Metadherin (MTDH) is overexpressed in over 40% of breast cancer patients and promotes metastasis and chemoresistance in experimental models of breast cancer progression. Here we applied mass spectrometry-based screen to identify staphylococcal nuclease domain-containing 1 (SND1) as a candidate MTDH-interacting protein. After confirming the interaction between SND1 and MTDH, we tested the role of SND1 in breast cancer and found that it strongly promotes lung metastasis. SND1 was further shown to promote resistance to apoptosis and to regulate the expression of genes associated with metastasis and chemoresistance. Analyses of breast cancer clinical microarray data indicated that high expression of SND1 in primary tumors is strongly associated with reduced metastasis-free survival in multiple large scale data sets. Thus, we have uncovered SND1 as a novel MTDH-interacting protein and shown that it is a functionally and clinically significant mediator of metastasis.

Gallbladder cancer is an aggressive cancer with extremely poor prognosis. Over 90% of patients are diagnosed at an advanced, inoperable stage with metastasis and invasion to other organs. In this study, the expression of metadherin (MTDH) and erythropoietin-producing hepatoma-amplified sequence (Eph) receptor A7 (EphA7) in 96 benign and 108 malignant lesions of gallbladder was determined by immunohistochemistry, and their correlations with pathological features and prognosis were analyzed. Positive expression of EphA7 and MTDH was significantly higher in gallbladder adenocarcinoma than in benign lesions. In adenocarcinoma, the positive expression of EphA7 and MTDH was significantly associated with differentiation, tumor mass, lymphnode metastasis, invasion, and overall survival. Multivariate Cox regression analysis suggested that positive expression of EphA7 and MTDH was an independent poor-prognostic predictor in gallbladder adenocarcinoma. The elevated expression of EphA7 and/or MTDH is closely related to carcinogenesis, progression, clinical biological behaviors, and prognosis of gallbladder adenocarcinoma.

expression of astrocyte-elevated gene-1, a novel oncoprotein, is elevated in multiple cancers and plays a vital role in tumor cell growth, invasion, angiogenesis, and progression to metastasis. However, the functional significance of astrocyte-elevated gene-1 in non-small cell lung cancer still remains unclear. Our present study showed that the markedly up-regulated expression of astrocyte-elevated gene-1 was observed in non-small cell lung cancer cell lines and tissues at the level of both transcription and translation. Simultaneously, ectopic expression or small interfering RNA silencing of astrocyte-elevated gene-1 markedly enhanced or inhibited the invasive ability of non-small cell lung cancer cells, respectively. At the molecular level, we also revealed that the function of astrocyte-elevated gene-1 in promoting metastasis was associated with the activation of matrix metalloproteinase-9 expression. Consistent with these observations, immunostaining analysis revealed a significant positive correlation between astrocyte-elevated gene-1 and matrix metalloproteinase-9. Moreover, subcutaneous xenografts of non-small cell lung cancer cells engineered to express astrocyte-elevated gene-1 were highly invasive compared with the parental cells and expressed a high level of matrix metalloproteinase-9. In archival non-small cell lung cancer specimens, high astrocyte-elevated gene-1 expression correlated significantly with clinical staging (P = .048), differentiation (P = .023), and lymph node metastasis (P = .032). The overall survival time in patients with high astrocyte-elevated gene-1 expression was notably shorter than that in patients with low astrocyte-elevated gene-1 expression (P < .001). Taken together, our results indicate that astrocyte-elevated gene-1 plays a crucial role in the carcinogenesis and aggressiveness of non-small cell lung cancer, promoting its metastasis by modulating matrix metalloproteinase-9 expression and leading to a poor clinical prognosis.

Astrocyte elevated gene 1 (AEG-1) expression is up-regulated in various human cancers and plays an important role in tumorigenesis and progression. The aim of this study was to explore AEG-1 expression in oral squamous cell carcinoma (OSCC) and to assess whether it is associated with microvessel density (MVD), metastasis, and survival. Specimens from 87 patients with OSCC were investigated by immunohistochemistry staining for AEG-1 and MVD. By statistical analysis, we studied the correlations between the expression of AEG-1 and MVD and various clinicopathological factors, including overall survival (OS). We found that AEG-1 was highly expressed in 51.72% of OSCC. expression was closely correlated with differentiation, clinical stage, T classification, and lymph node metastasis. The MVD had similar results. expression of AEG-1 correlated positively with MVD. The lymph node metastatic rate in patients with high AEG-1/high MVD was significantly higher than in patients with high AEG-1/low MVD, low AEG-1/high MVD, or low AEG-1/low MVD. Patients with high AEG-1 expression showed far lower OS rates than those with low expression. For MVD, there were similar results. Only AEG-1 and MVD expression were independent prognostic factors for OS by multivariate analysis. expression of AEG-1 may be correlated with tumor angiogenesis and metastasis and is a valuable prognostic factor in patients with OSCC.

OBJECTIVES: Osteosarcoma (OS) is one of the most common primary malignant bone tumours of childhood and adolescence, and is characterized by high propensity for metastasis (specially to the lung), which is the main cause of death. However, molecular mechanisms underlying metastasis of OS are still poorly understood. MATERIALS AND METHODS: Metadherin (MTDH) was identified to be significantly upregulated in OS tissues that had metastasized compared to OS without metastasis, using a two-dimensional approach of electrophoresis, coupled with mass spectrometry. To understand the function of MTDH in OS, OS cell lines U2OS and SOSP-M were transfected with retroviral shRNA vector against MTDH. RESULTS: It was found that metastatic propensity as well as cell proliferation were significantly reduced in both U2OS and SOSP-M. Migration and invasion of U2OS and SOSP-M cells were significantly lower after knock-down of MTDH. In addition, epithelial-mesenchymal transition (EMT) was reduced after knock-down of MTDH. Clinicopathologically, overexpression of MTDH was significantly associated with metastasis and poor survival of patients with OS. CONCLUSION: Taken together, our results demonstrate that MTDH mediated metastasis of OS through regulating EMT. This could be an ideal therapeutic target against metastasis of OS.

OBJECTIVE: Despite advances in chemotherapy and cytoreductive surgery, ovarian cancer remains the most lethal gynecological malignancy with a 5-year survival rate of 25% to 30% in advanced stage disease. Our purpose is to evaluate whether astrocyte elevated gene-1 (AEG-1) is a novel predictor of peritoneal dissemination and lymph node metastasis in epithelial ovarian cancer (EOC), which was not previously studied by others. MATERIALS AND METHODS: Through immunohistochemical and Western blot analysis, AEG-1 expression was evaluated in 25 normal ovarian and 157 EOC specimens. The relationship between AEG-1 expression and EOC metastasis was determined by univariate and multivariate analyses. RESULTS: Western blotting analysis revealed that AEG-1 was overexpressed in metastatic tissues from patients with ovarian cancers. Immunohistochemistry results showed that 83 (95.4%) presented peritoneal dissemination; 41 (47.1%) had lymph node metastasis among 87 patients with AEG-1 overexpression. Univariate and multivariate logistic regression analyses demonstrated that AEG-1 overexpression correlated with peritoneal dissemination and lymph node metastasis in EOC. We further found that the positive and specificity predictive value of AEG-1 staining were better for peritoneal metastasis, whereas the negative and sensitivity predictive value of AEG-1 staining were better for lymph node metastasis. The odds ratio of high-to-low expression for peritoneal dissemination was 8.541 (95% confidence interval, 2.561-37.461), and that for lymph node metastasis was 9.581 (95% confidence interval, 2.613-23.214). CONCLUSIONS: The present findings indicate that AEG-1 is overexpressed in a great portion of EOC patients with peritoneal dissemination and/or lymph node metastasis and may be clinically useful for predicting metastasis in EOC. Our findings might provide some benefits for metastatic EOC patients in the clinic.

Metadherin (MTDH) overexpression in diverse cancer types has been linked to poor clinical outcomes, but definitive genetic proof of its contributions to cancer remains incomplete. In particular, the degree to which MTDH may contribute to malignant progression in vivo is lacking. Here, we report that MTDH is amplified frequently in human prostate cancers where its expression levels are tightly correlated with prostate cancer progression and poor disease-free survival. Furthermore, we show that genetic ablation of MTDH in the transgenic adenomcarcinoma of mouse prostate (TRAMP) transgenic mouse model of prostate cancer blocks malignant progression without causing defects in the normal development of the prostate. Germline deletion of Mtdh in TRAMP mice prolonged tumor latency, reduced tumor burden, arrested progression of prostate cancer at well-differentiated stages, and inhibited systemic metastasis to distant organs, thereby decreasing cancer-related mortality approximately 10-fold. Consistent with these findings, direct silencing of Mtdh in prostate cancer cells decreased proliferation in vitro and tumor growth in vivo, supporting an epithelial cell-intrinsic role of MTDH in prostate cancer. Together, our findings establish a pivotal role for MTDH in prostate cancer progression and metastasis and define MTDH as a therapeutic target in this setting. cancer Res; 74(18); 5336-47. (c)2014 AACR.

The aim of this study was to examine the expression and role of astrocyte elevated gene-1 (AEG-1) in biological processes of T-cell non-Hodgkin's lymphoma (T-NHL). AEG-1 expression in T-NHL patients was characterized with immunohistochemistry. The expression of AEG-1, survivin, Bcl-2 and Bax in Jurkat and Hut-78 cells was detected by real-time PCR and western blotting. Cell proliferation, cell cycle and apoptosis were measured by MTT and flow cytometry. MMP-2/-9 activity was detected by gelatin zymography. Of the studied tumors, 104 (80.62%) exhibited cytoplasmic AEG-1 immunostaining. AEG-1-siRNA in Jurkat and Hut-78 cells suppressed cell proliferation and induced cell apoptosis, inhibited survivin and Bcl-2/Bax protein expression as well as MMP-2/-9 activity. Downregulation of AEG-1 using siRNA could provide a potential approach for gene therapy against T-NHL, and the antitumor effects may be associated with inhibition of survivin and Bcl-2/Bax protein expression and MMP-2/-9 activity.