Metadherin Expression Research Articles

Metadherin promotes metastasis by supporting putative cancer stem cell properties and epithelial plasticity in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) has a high metastatic potential. However, the mechanism of metastatic colonization in PDAC remains poorly understood. Metadherin (MTDH) has emerged in recent years as a crucial mediator of metastasis in several cancer types, although the biological role of MTDH in PDAC has not been investigated. Here, we demonstrated the functional roles of MTDH in PDAC progression, especially focusing on the metastatic cascade. In vitro studies showed that MTDH provides cancer stem cell (CSC) properties in metastatic PDAC cells and contributes to anoikis resistance with epithelial characteristics in PDAC cells. We also performed in vivo studies using both orthotopic transplantation and intra-portal vein injection as experimental models of liver metastasis to examine the function of MTDH at the metastatic site. MTDH knockdown dramatically reduced the incidence of liver metastases along with epithelial features in both experimental mouse models. Collectively, MTDH facilitates metastatic colonization with putative CSC and epithelial properties in PDAC cells. PDAC cells were transiently treated with TGF-β1 to investigate the roles of MTDH on epithelial plasticity. Intriguingly, MTDH expression was negatively correlated with Twist1 expression during the Mesenchymal-Epithelial transition (MET) induction in metastatic PDAC cells. These results suggest that MTDH may contribute to MET induction via downregulation of Twsit1. Lastly, immunohistochemistry indicated that MTDH overexpression is closely associated with hematogenous metastasis and predicts poor prognosis in patients with PDAC. This is the first demonstration of MTDH function in PDAC metastatic colonization. Our data suggest that MTDH targeting therapy could be applied to control PDAC metastasis.

Post-trimodality expression levels of metadherin (MTDH) as a prognostic biomarker for esophageal adenocarcinoma patients.

Resectable esophageal adenocarcinoma (EAC) patients often receive chemoradiation followed by surgery. However, most patients experience recurrences. Overexpression of MTDH, an oncoprotein with multiple functions, has been found to be associated with poor prognosis in breast cancer, glioblastoma, melanoma and various gastrointestinal malignancies, but not in EAC. We sought to establish its role in resistant EAC (post-treatment residual EAC). MTDH was assessed by immunohistochemistry in resected EAC, and results were correlated with clinical outcomes. MTDH expression was detectable in 72.5% (50/69) of patients, while expression levels were high (positive) in 50.7% (35/69). Of 69 patients analyzed, 25 had no relapse and 44 patients had a relapse (8 with local-regional and 36 with distant). The median follow-up duration was 3years (0.4-11.6). The median overall survival was not associated with MTDH status (2.79years for MTDH-negative and 3.60years for MTDH-positive patients, p=0.121). In addition, MTDH was not associated with either the type of relapse (local or distant), baseline clinical stage, tumor grade, presence of signet ring cells, surgical (yp) stage, percentage of residual EAC or presence of lymphovascular invasion. Our data reveal that MTDH is not a prognostic biomarker in resistant EAC after trimodality therapy.

Metadherin regulates actin cytoskeletal remodeling and enhances human gastric cancer metastasis via epithelial-mesenchymal transition.

Metadherin (MTDH) can be recruited to mature tight junction complexes, and it regulates mesenchymal marker protein expression in many tumors and promote cancer metastasis. This study investigated the influence of MTDH expression on gastric cancer and to elucidate the potential mechanisms by which MTDH regulates actin cytoskeletal remodeling and enhances human gastric cancer metastasis via epithelial-mesenchymal transition (EMT). Relative MTDH mRNA expression levels were assessed by quantitative real-time PCR (Q-PCR), and MTDH protein expression levels and localization were evaluated via immunohistochemical (ICH) staining. We studied the role of MTDH in cancer cell migration and invasion by modulating MTDH expression in the gastric cancer cell lines MKN45 and AGS. We also confirmed the functions of MTDH through in vivo experiments. We found that MTDH expression levels were correlated with lymph node metastasis, TNM stages and decreased OS (P=0.002, <0.001 and 0.010, respectively) in human gastric cancer and that MTDH upregulation promoted EMT in vitro. Consistent with this finding, MTDH downregulation inhibited cell migration and invasion in vitro and suppressed tumor growth and metastasis in vivo. Furthermore, MTDH knockdown regulated actin cytoskeletal remodeling and inhibited EMT. Overall, our results provide a novel role for MTDH in regulating gastric cancer metastasis.

Significance and expression of metdherin in gastric adenocarcinoma and its regulating mechanism of invasion and migration

Objective This study aimed at observing expression and clinical significance of metadherin in gastric adenocarcinoma and exploring the potentially regulating mechanism of metadherin in invation and migration of gastric cancer. Methods Expressions of metadherin and E-cadherin in primary lesion of gastric cancer were detected by immunohistochemistry and their correlation to clinicopathologic characteristics and prognosis were analyzed by Chi-square tests. Transwell assay and wound healing assay were applied for the ability of invasion and metastasis in gastric cancer cells. Then, the down-regulatied metadherin expression in MKN45 cells by RNA interference (siRNA) was carried out and furthermore, the regulation role of metadherin in epithelial-mesenchymal transition was analyzed also in invasion and migration of gastric cancer cells. Results The positive expression of metadherin was correlated to invading depth (P=0.029), lymph node metastasis (P=0.001), TNM stage (P=0.014) and inhibiting E-cadherin expression (P=0.001). The patients with positive metabherin shared poorer prognosis. Furthermore, the down-regulated metabherin in MKN45 cells would result in the increasing expression of E-cadherin, as well as decreasing expression of N-cadherin, Slug and Snail. At the same time, the abilities of invasion (P=0.027) and migration (P=0.008) of MKN45 cells was decreased. Conclusion metabherin induces EMT in metastasis of gastric adenocarcinoma via activating either Slug or Snail but not twist, which would result in the poorer prognosis. Key words: MTDH; Stomach neoplasms; Epithelial-mesenchymal transition; Metastasis; Prognosis; Chi-Square distribution

MicroRNA-375 suppresses esophageal cancer cell growth and invasion by repressing metadherin expression.

Accumulating evidence indicates that aberrant expression of microRNAs is involved in tumorigenesis, tumor progression and response to therapy. MicroRNA-375 (miR-375) is an important cancer-associated RNA that is downregulated in multiple types of cancer. In the present study, the potential effects of and underlying molecular mechanism for miR-375 in esophageal cancer were investigated. The expression of miR-375 in paired esophageal squamous cell carcinoma (ESCC) and non-tumor tissues from 10 patients was quantified using the reverse transcription-quantitative polymerase chain reaction. The miR-375 levels in the ESCC cell line EC109 and a normal esophageal epithelial cell line, Het-1A, were also detected. The effect of miR-375 on ESCC cell growth and invasion was determined using Cell Counting kit-8, flow cytometry and invasion assays. A luciferase assay was conducted for target identification. The results of the present study revealed that miR-375 was downregulated in ESCC tumor tissue and EC109 cells compared with normal tissue and Het-1A cells (P<0.01). Overexpression of miR-375 inhibited EC109 cell growth and invasion, and induced cell cycle arrest. In addition, metadherin (MTDH) was demonstrated to be a direct target of miR-375 (P<0.01). The overexpression of miR-375 downregulated MTDH (P<0.01), cyclin D1 (P<0.05) and vascular endothelial growth factor (P<0.01) expression, while upregulating epithelial cadherin (P<0.01) expression, which may account for its effect on ESCC cell proliferation and invasion. The results of the present study suggest that the miR-375/MTDH axis represents a target for the treatment of ESCC.

MicroRNA-202 inhibits cell proliferation, migration and invasion of glioma by directly targeting metadherin.

Glioma is the most common and aggressive type of primary malignant brain tumour. Increasing evidence has revealed that microRNAs play important roles in multiple biological processes related to glioma occurrence, development, diagnosis, treatment and prognosis. MicroRNA-202 (miR-202) has been studied in several types of human cancer, whereas the biological roles of miR-202 in glioma remain unknown. The present study, aimed to investigate the expression, clinical significance and biological roles of miR-202 in glioma, as well as its underlying molecular mechanism. We found that miR-202 was significantly downregulated in glioma tissues and cell lines. Low miR-202 expression was associated with Karnofsky performance status (KPS) score and World Health Organization (WHO) grade of glioma patients. Functional assays revealed that ectopic expression of miR-202 inhibited cell proliferation, migration and invasion of glioma. In addition, metadherin (MTDH) was identified as a direct target gene of miR-202 in glioma through bioinformatic analysis, luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Furthermore, MTDH expression was upregulated and negatively correlated with miR-202 expression in clinical glioma tissues. MTDH knockdown had similar roles to miR-202 overexpression in glioma cells. Rescue experiments revealed that upregulation of MTDH reversed the suppression of glioma cell growth and metastasis by miR-202. Moreover, miR-202 impaired the PI3K/Akt and Wnt/β-catenin pathways. These results highlight the tumour-suppressive effect of miR-202 in glioma, thereby suggesting that miR-202 may be a potential therapeutic target for the treatment of patients with this malignancy.

MiR-217 suppresses proliferation, migration, and invasion promoting apoptosis via targeting MTDH in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) has frequent incidence and the third highest mortality rate among cancers in the world. This study aimed to clarify the roles of miR-217 and metadherin (MTDH) in HCC. First, we identified that miR-217 expression was downregulated and MTDH expression was upregulated in the HCC tissues. Functional studies revealed that miR-217 negatively regulated MTDH expression via binding to the 3'-untranslated region of MTDH mRNA in the HCC cells. In our further studies, the miR-217 overexpression resulted in downregulation of MTDH expression in HCC cells. The miR-217 overexpression in HCC cells suppressed proliferation, migration, and invasion inducing apoptosis. Taken together, our study provides the initial evidence that the increase of MTDH expression is associated with the decrease of miR-217 expression in HCC. This study also suggests that miR-217 inhibits malignant progression of HCC invitro and may be used for miRNA-based therapy, possibly via directly targeting MTDH.

Abstract B29: The elucidation for functional roles of Metadherin in metastatic cascade of pancreatic cancer

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. At present, surgical resection is the only curative treatment for PDAC, but the majority of PDAC patients show early recurrence even after curative resection. There is a possibility of having been distant micrometastasis at early stage of carcinogenesis in PDAC. The control of PDAC metastatic progression leads to improve the prognosis of PDAC patients. Recently, it is reported that a verified mediator of distant metastasis, Metadherin (MTDH), promotes metastasis in experimental models of breast cancer, and its high expression is associated with poor prognosis in a large spectrum of cancer types. Recent evidences imply that the epithelial-mesenchymal transition (EMT) and putative cancer stem cell (CSC) functions orchestrates to play crucial roles in cancer progression. In this study, we aim to investigate the function of MTDH in PDAC progression concomitant with undergoing EMT/MET plasticity or involving putative CSC functions. Experimental methods: We investigated MTDH expression in 7 human and 6 mouse PDAC cell lines and elucidated the roles of MTDH in PDAC progression by in vitro experiments for the loss of function using siMTDH and shMTDH. In immunohistochemical (IHC) staining of MTDH in resected PDAC tissues, we analyzed the correlation between MTDH expression and the clinico-pathological parameters as well as clinical outcome of the 82 PDAC patients. Results: Western blot analyses showed higher MTDH protein expression in metastatic PDAC compared to primary PDAC cell lines. In metastatic cell lines, MTDH expression has a positive correlation with E-cadherin expression. These data suggest that MTDH might be related to mesenchymal-epithelial transition (MET) and play a crucial role in metastatic cascade of PDAC. Conversely, MTDH has a negative correlation with E-cadherin in primary PDAC cell lines. It is implicated that MTDH might play inverse functions in primary site and metastatic site. Next, to examine what is the role of MTDH in the EMT/MET process, we evaluated the expression pattern of EMT markers and MTDH in response to transient TGF-β1 treatment. We found that E-cadherin expression decreases at 8 to 24 hours after treatment (EMT initiation), and then comes back to increase of the expression at 4 days after treatment (MET induction). While MTDH and E-cadherin expression shows an inverse relation during EMT initiation, these two expressions have a positive correlation during MET period (from 7 days after treatment). Additionally, we found EMT induction by TGF-β1 is attenuated by knockdown of MTDH, These results suggest MTDH might contribute to the phenotypic switch of PDAC cells via the EMT/MET process. MTDH knockdown significantly impaired the ability of pancreatosphere formation in PDAC cells and sensitized PDAC cells to gemcitabine. In FACS analyses, we also found that the percentage of CD133-positive cancer stem cell subpopulation was significantly reduced in MTDH knockdown metastatic PDAC cells. In anoikis assay, (this assay evaluate the resistance for apoptosis after losing contact from extracelluar matrix), MTDH knockdown reduced anoikis resistance in PDAC cells. These data indicate that MTDH might foster putative CSC functions in PDAC cells. In IHC staining, high MTDH expression indicated significantly higher incidence of hematogenous metastasis (p=0.02). Furthermore, High expression group showed poorer prognosis of PDAC patients compared to Low expression group in Kaplan Meier analysis (p=0.029). Conclusions: MTDH might promote PDAC metastasis to undergo EMT in primary PDAC and MET in metastatic PDAC along with.putative CSC functions. The regulation of MTDH might develop the new strategy for PDAC treatment, and lead to improve the outcome of patients. Citation Format: Kensuke Suzuki, Shigetsugu Takano, Hideyuki Yoshitomi, Shingo Kagawa, Hiroaki Shimizu, Masayuki Otsuka, Katunori Furukawa, Tukasa Takayashiki, Satoshi Kuboki, Daisuke Suzuki, Nozomu Sakai, Hiroyuki Nojima, Masaru Miyazaki.{Authors}. The elucidation for functional roles of Metadherin in metastatic cascade of pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B29.

Association of MTDH immunohistochemical expression with metastasis and prognosis in female reproduction malignancies: a systematic review and meta-analysis.

Various literatures have demonstrated that overexpression of Metadherin (MTDH) is correlated with tumor metastasis and it can predict poor survival outcomes in female reproduction malignancies. In order to enhance the statistical power and reach a recognized conclusion, we conducted a systematic review and meta-analysis to thoroughly investigate the association of MTDH expression with tumor metastasis and survival outcomes following PRISMA guidelines. Odds ratios (ORs) and hazard ratios (HRs) were used to demonstrate the impact of MTDH on tumor metastasis and prognosis respectively. Data were pooled with appropriate effects model on STATA12.0. Our results indicated that high MTDH expression is significantly correlated with higher mortality for breast, ovarian and cervical cancer. High immunohistochemical expression of MTDH is remarkably associated with shorter disease-free survival (DFS) in breast cancer but not in ovarian cancer. The pooled results suggested that high level of MTDH significantly predicted distant metastasis and lymph node metastasis in breast cancer. Strong associations were observed between MTDH expression and lymph node metastasis in ovarian and cervical cancer. In conclusion, MTDH might be a novel biomarker which can effectively reflect metastasis status and prognosis of breast cancer. However, its application in clinical practice needs more prospective studies with large samples.

Gene expression profiling of the 8q22-24 position in human breast cancer: TSPYL5, MTDH, ATAD2 and CCNE2 genes are implicated in oncogenesis, while WISP1 and EXT1 genes may predict a risk of metastasis.

Gene expression profiling has been suggested to predict breast cancer outcome. The prognostic value of the 8q22-24 position in breast cancer remains to be elucidated. The present study evaluated expression patterns of the genes located at this position in metastatic and non-metastatic breast cancer. A total of 85 patients with recurrent/metastatic (n=15) and non-metastatic (n=70) early-stage, estrogen receptor-positive and lymph node-negative breast tumors were included. In addition, 15 normal breast tissue samples were used as controls. Demographic and clinical features were recorded. Subsequently, mRNA copy numbers of exostosin glycosyltransferase 1 (EXT1), WNT1 inducible signaling pathway protein 1 (WISP1), ATPase family, AAA domain containing 2 (ATAD2), TSP-like 5 (TSPYL5), metadherin (MTDH) and cyclin E2 (CCNE2) genes were measured by reverse transcription-quantitative polymerase chain reaction assay. The expression of EXT1 and WISP1 exhibited a significant decline in the metastatic breast cancer group compared to the control (P=0.015 and P=0.012, respectively). The expression of TSPYL5, MTDH and ATAD2 was significantly decreased in the metastatic (P=0.002, P=0.018 and P=0.016, respectively) and non-metastatic (P=0.038, P=0.045 and P=0.000, respectively) breast cancer groups compared with the control. The expression of CCNE2 in the metastatic and non-metastatic breast cancer groups was significantly increased compared with the control (P=0.002 and P=0.001, respectively). WISP1 expression demonstrated a correlation with patient age and tumor size, and TSPYL5 expression was correlated with lymphovascular invasion. None of the genes investigated exhibited any correlation with stage and grade of disease. The TSPYL5, MTDH, ATAD2 and CCNE2 genes may be implicated in the pathogenesis of human breast cancer, while the WISP1 and EXT1 genes may have the potential to serve as promising indicators of the risk of metastasis. However, further studies are required to validate these results.

Dual-strand tumor-suppressor microRNA-145 (miR-145-5p and miR-145-3p) coordinately targeted MTDH in lung squamous cell carcinoma.

Patients with lung adenocarcinoma may benefit from recently developed molecular targeted therapies. However, analogous advanced treatments are not available for patients with lung squamous cell carcinoma (lung SCC). The survival rate of patients with the advanced stage of lung SCC remains poor. Exploration of novel lung SCC oncogenic pathways might lead to new treatment protocols for the disease. Based on this concept, we have identified microRNA- (miRNA) mediated oncogenic pathways in lung SCC. It is well known that miR-145-5p (the guide strand) functions as a tumor suppressor in several types of cancer. However, the impact of miR-145-3p (the passenger strand) on cancer cells is still ambiguous. Expression levels of miR-145-5p and miR-145-3p were markedly reduced in cancer tissues, and ectopic expression of these miRNAs inhibited cancer cell aggressiveness, suggesting that both miR-145-3p as well as miR-145-5p acted as antitumor miRNAs. We identified seven putative target genes (MTDH, EPN3, TPD52, CYP27B1, LMAN1, STAT1 and TXNDC12) that were coordinately regulated by miR-145-5p and miR-145-3p in lung SCC. Among the seven genes, we found that metadherin (MTDH) was a direct target of these miRNAs. Kaplan–Meier survival curves showed that high expression of MTDH predicted reduced survival of lung SCC patients. We investigated pathways downstream from MTDH by using genome-wide gene expression analysis. Our data showed that several anti-apoptosis and pro-proliferation genes were involved in pathways downstream from MTDH in lung SCC. Taken together, both strands of miR-145, miR-145-5p and miR-145-3p are functional and play pivotal roles as antitumor miRNAs in lung SCC.

MicroRNA-320a inhibits breast cancer metastasis by targeting metadherin.

Dysregulated microRNAs play important pathological roles in carcinogenesis that are yet to be fully elucidated. This study was performed to investigate the biological functions of microRNA-320a (miR-320a) in breast cancer and the underlying mechanisms. Function analyses for cell proliferation, cell cycle, and cell invasion/migration, were conducted after miR-320a silencing and overexpression. The specific target genes of miR-320a were predicted by TargetScan algorithm and then determined by dual luciferase reporter assay and rescue experiment. The relationship between miR-320a and its target genes was explored in human breast cancer tissues. We found that miR-320a overexpression could inhibit breast cancer invasion and migration abilities in vitro, while miR-320a silencing could enhance that. In addition, miR-320a could suppress activity of 3′-untranslated region luciferase of metadherin (MTDH), a potent oncogene. The rescue experiment revealed that MTDH was a functional target of miR-320a. Moreover, we found that MTDH was negatively correlated with miR-320a expression, and it was related to clinical outcomes of breast cancer. Further xenograft experiment also showed that miR-320a could inhibit breast cancer metastasis in vivo. Our findings clearly demonstrate that miR-320a suppresses breast cancer metastasis by directly inhibiting MTDH expression. The present study provides a new insight into anti-oncogenic roles of miR-320a and suggests that miR-320a/MTDH pathway is a putative therapeutic target in breast cancer.

Metadherin Expression is Associated with Extrathyroidal Extension in Papillary Thyroid Cancer Patients.

Metadherin (MTDH) is widely recognized as a promising molecular marker for tumor recurrence and poor survival in many cancers. By multiple pathways, MTDH promotes oncogenesis, metastasis, and chemoresistance. This study investigated the role of MTDH in papillary thyroid carcinoma (PTC) to determine its potential association with aggressive clinical and pathologic features, including its relation in tumors harboring a BRAF (V600E) mutation. Expression of MTDH was assessed by immunohistochemistry in 96 cases of PTC, including primary thyroid malignancies and lymph node metastases. The status of BRAF (V600E) mutation was determined by real-time polymerase chain reaction. Overexpression of MTDH was observed in 26% (23/88) of primary PTC cases. High-intensity staining was observed in 75% (6/8) of lymph nodes with metastatic PTC and moderate staining in 25% (2/8) of cases. Normal adjacent thyroid tissue and benign thyroid controls were found to have significantly lower MTDH expression than cancer tissue (p<0.05). Apical staining of MTDH was observed in 19% of thyroid tumors and not observed in normal thyroid tissue. Interestingly, MTDH expression was associated with extrathyroidal extension (p<0.05) and not associated with age, gender, overall tumor stage, or BRAF (V600E) mutation status. In a subset of PTC patients, MTDH was overexpressed and associated with extrathyroidal extension. Further studies are warranted to explore the utility of MTDH to improve risk stratification of current molecular panels for PTC.

MTDH is an oncogene in multiple myeloma, which is suppressed by Bortezomib treatment.

Metadherin (MTDH) is identified as an oncogene in multiple cancers including breast cancer, bladder cancer and endometrial cancer. However, the function of MTDH in multiple myeloma (MM) is still unexplored. In this study, we disclose that MTDH is an oncogene in MM. This is characterized by an elevation mRNA level of MTDH and chromosomal gain of MTDH locus in MM cells compared to normal samples. Moreover, MTDH expression significantly increased in MMSET translocation (MS) subgroup, one of the high-risk subgroups in MM, and was significantly correlated with MM patients' poor outcomes in Total Therapy 2 (TT2) cohort. Further knockdown of MTDH expression by shRNA in MM cells induced cell apoptosis, inhibited MM cells growth in vitro and decreased xenograft tumor formation in vivo. Interestingly, opposite to TT2, MM patients with high-MTDH expression showed favorable survival outcomes in the TT3 cohort, while Bortezomib treatment was the major difference between TT2 and TT3 cohort. Furthermore we proved that Bortezomib suppressed pre- and post-transcription levels of MTDH expression of MM cells in vitro and in vivo. Finally, our studies demonstrated that MTDH is a transcriptional gene of MMSET/NFκB /MYC signaling in MM cells, which is inhibited by Bortezomib treatment.

Correlated overexpression of metadherin and SND1 in glioma cells.

Glioma is the most common primary brain tumor with poor prognosis. Effective treatment of glioma remains a big challenge due to complex pathogenic mechanisms. Previous studies have shown that metadherin (MTDH) and its interacting protein staphylococcal nuclease domain containing 1 (SND1) are overexpressed in many solid tumors. To elucidate the role of MDTH and SND1 in the pathogenesis of glioma, we examined the expression of MTDH and SND1 in primary glioma tissues and found that both MTDH and SND1 were highly expressed, with similar expression patterns. Co-expression of MTDH and SND1 was associated with advanced glioma grades. In addition, we detected the interaction between MTDH and SND1 in cultured glioma cell lines. MTDH could promote the expression of p65 and SND1 in glioma cells. However, enhanced SND1 expression by MTDH was abolished by the inhibition of p65. In conclusion, we demonstrated high expression levels MTDH and SND1 in primary glioma tissues. MTDH might promote glioma by inducing SND1 expression through the activation of NF-κB pathway. MTDH and SND1 may serve as the indicator of malignancy and prognosis as well as therapeutic targets for patients with glioma.

Epigenetic Activation of TWIST1 by MTDH Promotes Cancer Stem–like Cell Traits in Breast Cancer

Cancer stem-like cells (CSC) are a cell subpopulation that can reinitiate tumors, resist chemotherapy, and give rise to metastases. Metadherin (MTDH) contributes widely to tumor growth, drug resistance, relapse, and metastasis, but its molecular mechanisms of action are not well understood. Here, we report that MTDH drives CSC expansion by promoting the expression of TWIST1, a transcription factor critical for cancer cell stemness and metastasis. MTDH activates TWIST1 expression indirectly by facilitating histone H3 acetylation on the TWIST1 promoter, a process mediated by the histone acetyltransferase CBP. Mechanistic investigations showed that MTDH interacts with CBP and prevents its ubiquitin-mediated degradation, licensing its transcriptional activation of TWIST1. In clinical specimens of breast cancer, MTDH expression correlates positively with TWIST1 expression and CSC abundance. Overall, our work revealed that MTDH promotes CSC accumulation and breast tumorigenicity by regulating TWIST1, deepening the understanding of MTDH function in cancer.

MiR-302c-3p suppresses invasion and proliferation of glioma cells via down-regulating metadherin (MTDH) expression

Glioma is the most common malignant brain tumors with poor prognosis. The molecular events involved in the development and progression of glioma remain unclear. In this study, the expression levels of miR-302c-3p were examined in glioma tissues by qRT-PCR. The in vitro and in vivo functional effects of miR-302c-3p were examined further. Luciferase reporter assays were conducted to confirm the targeting associations. Results showed that the expression level of miR-302c-3p in glioma tissues was significantly lower than those in normal brain tissues (P < 0.001). The decreased expression of mi-302c-3p in glioma was positively associated with WHO grade (P < 0.001). Up-regulation of MTDH was also detected in glioma tumors compared with normal brain tissues (P = 0.0027) and is inversely correlated with miR-302c-3p expression (P = 0.003, R2 = 0.4065). MTDH mRNA is a direct target of miR-302c-3p, whose ectopic expression decreases MTDH expression through binding to its 3′-untranslated region. Overexpression of miR-302c-3p results in a dramatic inhibition of glioma cells proliferation and invasion in vitro and in vivo. These data suggest that miR-302c-3p play a pivotal role in the progression of glioma by targeting MTDH and is a potential inhibitor in glioma treatment.

Molecular Modification of Metadherin/MTDH Impacts the Sensitivity of Breast Cancer to Doxorubicin.

BackgroundBreast cancer is a leading cause of death in women and with an increasing worldwide incidence. Doxorubicin, as a first-line anthracycline-based drug is conventional used on breast cancer clinical chemotherapy. However, the drug resistances limited the curative effect of the doxorubicin therapy in breast cancer patients, but the molecular mechanism determinants of breast cancer resistance to doxorubicin chemotherapy are not fully understood. In order to explore the association between metadherin (MTDH) and doxorubicin sensitivity, the differential expressions of MTDH in breast cancer cell lines and the sensitivity to doxorubicin of breast cancer cell lines were investigated.MethodsThe mRNA and protein expression of MTDH were determined by real-time PCR and Western blot in breast cancer cells such as MDA-MB-231, MCF-7, MDA-MB-435S, MCF-7/ADR cells. Once MTDH gene was knocked down by siRNA in MCF-7/ADR cells and overexpressed by MTDH plasmid transfection in MDA-MB-231 cells, the cell growth and therapeutic sensitivity of doxorubicin were evaluated using MTT and the Cell cycle assay and apoptosis rate was determined by flow cytometry.ResultsMCF-7/ADR cells revealed highly expressed MTDH and MDA-MB-231 cells had the lowest expression of MTDH. After MTDH gene was knocked down, the cell proliferation was inhibited, and the inhibitory rate of cell growth and apoptosis rate were enhanced, and the cell cycle arrest during the G0/G1 phase in the presence of doxorubicin treatment. On the other hand, the opposite results were observed in MDA-MB-231 cells with overexpressed MTDH gene.ConclusionMTDH gene plays a promoting role in the proliferation of breast cancer cells and its high expression may be associated with doxorubicin sensitivity of breast cancer.

Metadherin is required for the proliferation, migration, and invasion of esophageal squamous cell carcinoma and its meta-analysis

Metadherin (MTDH) was found to be highly expressed in various squamous cell carcinomas (SCCs); however, meta-analysis evaluating the association of MTDH in SCC has not been performed. The purpose of this study was to explore the biological functions of MTDH in esophageal squamous cell carcinoma (ESCC) and to meta-analyze the association between MTDH and SCC. Immunohistochemistry was performed to examine MTDH expression using an ESCC tissue array consisting of 86 ESCC and 78 paired normal adjacent tissues (NATs). MTDH was significantly overexpressed in ESCC tissues compared with NATs and was significantly associated with lymph node metastasis, differentiation, and prognosis. Knockdown of MTDH using an MTDH-short hairpin RNA plasmid caused cell cycle arrest at the G0/G1 phase and induced apoptosis of EC9706 cells. Knockdown of MTDH suppressed the proliferation, invasion, and migration of ESCC cells. Furthermore, meta-analysis revealed that overexpression of MTDH was significantly associated with the lymph node metastasis, advanced clinical stage, and T classification of tissues in SCC, suggesting that MTDH might be used as a potential therapeutic target in the lymph node metastasis of ESCC.

Genetic Deficiency of Mtdh Gene in Mice Causes Male Infertility via Impaired Spermatogenesis and Alterations in the Expression of Small Non-coding RNAs

Increased expression of metadherin (MTDH, also known as AEG-1 and 3D3/LYRIC) has been associated with drug resistance, metastasis, and angiogenesis in a variety of cancers. However, the specific mechanisms through which MTDH is involved in these processes remain unclear. To uncover these mechanisms, we generated Mtdh knock-out mice via a targeted disruption of exon 3. Homozygous Mtdh knock-out mice are viable, but males are infertile. The homozygous male mice present with massive loss of spermatozoa as a consequence of meiotic failure. Accumulation of γ-H2AX in spermatocytes of homozygous Mtdh knock-out mice confirms an increase in unrepaired DNA breaks. We also examined expression of the DNA repair protein Rad18, which is regulated by MTDH at the post-transcriptional level. In testes from Mtdh exon 3-deficient mice, Rad18 foci were increased in the lumina of the seminiferous tubules. The Piwi-interacting RNA (piRNA)-interacting protein Mili was expressed at high levels in testes from Mtdh knock-out mice. Accordingly, genome-wide small RNA deep sequencing demonstrated altered expression of piRNAs in the testes of Mtdh knock-out mice as compared with wild type mice. In addition, we observed significantly reduced expression of microRNAs (miRNAs) including miR-16 and miR-19b, which are known to be significantly reduced in the semen of infertile men. In sum, our observations indicate a crucial role for MTDH in male fertility and the DNA repair mechanisms required for normal spermatogenesis.