MTA1 Overexpression Research Articles

The Therapeutic Efficacy and Mechanism of Action of Gnetin C, a Natural Compound from the Melinjo Plant, in a Preclinical Mouse Model of Advanced Prostate Cancer.

The metastasis-associated protein 1/protein kinase B (MTA1/AKT) signaling pathway has been shown to cooperate in promoting prostate tumor growth. Targeted interception strategies by plant-based polyphenols, specifically stilbenes, have shown great promise against MTA1-mediated prostate cancer progression. In this study, we employed a prostate-specific transgenic mouse model with MTA1 overexpression on the background of phosphatase and tensin homolog (Pten) null (R26MTA1; Ptenf/f) and PC3M prostate cancer cells which recapitulate altered molecular pathways in advanced prostate cancer. Mechanistically, the MTA1 knockdown or pharmacological inhibition of MTA1 by gnetin C (dimer resveratrol) in cultured PC3M cells resulted in the marked inactivation of mammalian target of rapamycin (mTOR) signaling. In vivo, mice tolerated a daily intraperitoneal treatment of gnetin C (7 mg/kg bw) for 12 weeks without any sign of toxicity. Treatment with gnetin C markedly reduced cell proliferation and angiogenesis and promoted apoptosis in mice with advanced prostate cancer. Further, in addition to decreasing MTA1 levels in prostate epithelial cells, gnetin C significantly reduced mTOR signaling activity in prostate tissues, including the activity of mTOR-target proteins: p70 ribosomal protein S6 kinase (S6K) and eukaryotic translational initiation factor 4E (elF4E)-binding protein 1 (4EBP1). Collectively, these findings established gnetin C as a new natural compound with anticancer properties against MTA1/AKT/mTOR-activated prostate cancer, with potential as monotherapy and as a possible adjunct to clinically approved mTOR pathway inhibitors in the future.

Circ_0124055 promotes the progression of thyroid cancer cells through the miR-486-3p/MTA1 axis.

Thyroid cancer is one of the malignancy cancers. CircRNA, a non-coding RNA, plays an important role in the development of cancer. The relationship and roles of circ_0124055, miR-486-3p and MTA1 in thyroid cancer have not been reported. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to analyze the RNA levels of circ_0124055, miR-486-3p and MTA1. Western blot was conducted to analyze the protein levels of MTA1, Epithelial cadherin (E-cadherin) and Neuro cadherin (N-cadherin). Subcellular localization assay was used to analyze circ_0124055 location in thyroid cancer cells. Colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay were carried out to analyze cell proliferation. Cell migration and invasion were analyzed by wound-healing assay and transwell assay. Flow cytometry assay was performed to investigate cell apoptosis. Dual-luciferase reporter assay and RIP assay were employed to analyze the interactions among circ_0124055, miR-486-3p and MTA1. Immunohistochemical (IHC) assay was performed to assess the expression of Ki67, MTA1 and E-cadherin in tumor tissues. Thyroid cancer tumor growth in vivo was evaluated by tumor xenograft mouse model assay. The expression of circ_0124055 was up-regulated in tumor tissues and cells. Knockdown of circ_0124055 could inhibit thyroid cancer cell proliferation, migration and invasion and promote cell apoptosis, accompanied by the dysregulation of E-cadherin and N-cadherin expression. Circ_0124055 could target miR-486-3p, and miR-486-3p could target MTA1. MiR-486-3p inhibitor could restore the effect of circ_0124055 knockdown in the progression of thyroid cancer. Moreover, MTA1 overexpression weakened the inhibitory effects of miR-486-3p mimics on the progression of thyroid cancer. Further, circ_0124055 could influence tumor growth in vivo. Circ_0124055 promoted the progression of thyroid cancer cells through the miR-486-3p /MTA1 axis.

Antisense oligonucleotide p45Skp-2 suppresses migratory chemotactic and metastasis of oral malignant Burkitt’s lymphoma cell through down-regulation of MTA-1 and induction of E-cadherin mechanism

Introduction: Burkitt’s lymphoma is a high-grade B-cell neoplasm and one of the most aggressive malignancies of lymphoid origins which found mainly in the paediatric population. The treatment options of this tumour are still limited. However, a new strategy for refractory tumour, phosphorothioate oligonucleotide antisense technique has watched with keen interest. This study was aimed to examine the effect of antisense p45Skp-2 (Skp-2 AS) suppressed migratory chemotactic and metastasis of oral malignant Burkitt’s lymphoma (Raji) cell through down-regulation of MTA-1 and E-cadherin. Methods: True experiment laboratory with post-test control group design was confirmed in this study. The efficiency of Skp-2 AS in the suppression of cell chemotactic migration was examined by Boyden chamber assay. To evaluate the inhibition of cell metastasis was conducted by decreasing MTA-1 expression protein. The expressions of MTA-1, E-cadherin and α-tubulin protein were investigated by Western blot analysis. Results: The results revealed that the number of chemotactic migration of Skp-2 AS treated Raji cell was significantly decreased when compared with that of sense p45Skp-2 (Skp-2 S) and scrambled control (SC) cells (P<0.05) followed by decreased expressions of MTA-1 protein and overexpression of E-cadherin. Interestingly, the expression of α-tubulin protein as an internal control was approximately similar in each transfectant cells. Conclusion: p45Skp-2 have an antitumor activity via suppression of migratory chemotactic activity and metastasis on oral Burkitt’s lymphoma cells through down-regulation of MTA-1 and induction of E-cadherin proteins targeting this molecule could represent a promising new therapeutic approach for this type of cancer.

Abstract 1144: Novel prostate cancer mouse models for testing targeted chemopreventive potential of pterostilbene

Abstract Metastasis-associated protein 1 (MTA1) plays role in prostate cancer progression and metastasis. We have previously reported on the MTA1-targeted chemopreventive and therapeutic efficacy of pterostilbene (Pter) in the prostate-specific Pten heterozygous (Pten+/f; Pb-Cre+) and Pten null (Ptenf/f; Pb-Cre+) mice. To investigate the exact role of MTA1 in prostate cancer tumorigenesis and its early stages, we developed appropriate mouse models, namely prostate-specific MTA1-knocked in (MTA1-tg) and MTA1-tg on the background of prostate-specific Pten heterozygosity (MTA+/+, Pten+/f; Pb-Cre+). In the current project, we asked three major questions: 1) whether prostate MTA1 overexpression in the context of Pten loss promotes an earlier onset, greater total incidence and accelerated PIN or tumor growth rate; 2) what MTA1-associated molecules are involved in prostate cancer progression; and 3) whether Pter supplemented diet can provide beneficial effects. Identified from our ChIP-Seq data MTA1-associated molecules included CyclinD1, Notch2, and two neuroendocrine markers, namely CHGA and SYP. Using two prostate cancer cell lines, DU145 and PC3M and their corresponding MTA1 knockdown (shMTA1) clones, we validated the direct link between MTA1 and these markers on mRNA and protein levels. Further, we generated 28 prostate-specific MTA1+/+; Pten+/f; Pb-Cre+ mice and randomized them into two major groups: 1) mice on control diet (Ctrl-Diet) and 2) mice on Pter-Diet. After 5 months of feeding with corresponding diets (AIN-76A phytoestrogen free diets supplemented or not with Pter at 100 mg/kg/diet), mice were sacrificed and prostate tissues were isolated for histological, immunochemical and molecular analysis. Results demonstrated the contribution of MTA1 in more aggressive histological phenotype (Ki67, PCNA, p27, SMA, CK8), increased levels of oncogenic MTA1-guided molecules (CyclinD1, Notch2, CHGA, SYP, AR) and the potential for Pter in prostate cancer chemoprevention. Citation Format: Rutu Hemani, Ninad Inamdar, Avinash Kumar, Virginia Donovan, Anait S. Levenson. Novel prostate cancer mouse models for testing targeted chemopreventive potential of pterostilbene [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1144.

A TGF-β-MTA1-SOX4-EZH2 signaling axis drives epithelial-mesenchymal transition in tumor metastasis.

MTA1, SOX4, EZH2, and TGF-β are all potent inducers of epithelial-mesenchymal transition (EMT) in cancer; however, the signaling relationship among these molecules in EMT is poorly understood. Here, we investigated the function of MTA1 in cancer cells and demonstrated that MTA1 overexpression efficiently activates EMT. This activation resulted in a significant increase in the migratory and invasive properties of three different cancer cell lines through a common mechanism involving SOX4 activation, screened from a gene expression profiling analysis. We showed that both SOX4 and MTA1 are induced by TGF-β and both are indispensable for TGF-β-mediated EMT. Further investigation identified that MTA1 acts upstream of SOX4 in the TGF-β pathway, emphasizing a TGF-β-MTA1-SOX4 signaling axis in EMT induction. The histone methyltransferase EZH2, a component of the polycomb (PcG) repressive complex 2 (PRC2), was identified as a critical responsive gene of the TGF-β-MTA1-SOX4 signaling in three different epithelial cancer cell lines, suggesting that this signaling acts broadly in cancer cells in vitro. The MTA1-SOX4-EZH2 signaling cascade was further verified in TCGA pan-cancer patient samples and in a colon cancer cDNA microarray, and activation of genes in this signaling pathway predicted an unfavorable prognosis in colon cancer patients. Collectively, our data uncover a SOX4-dependent EMT-inducing mechanism underlying MTA1-driven cancer metastasis and suggest a widespread TGF-β-MTA1-SOX4-EZH2 signaling axis that drives EMT in various cancers. We propose that this signaling may be used as a common therapeutic target to control epithelial cancer metastasis.

Overexpression of MTA1 inhibits the metastatic ability of ZR-75-30 cells in vitro by promoting MTA2 degradation

BackgroundAs the first member of the metastasis-associated protein (MTA) family, MTA1 and another MTA family member, MTA2, have both been reported to promote breast cancer progression and metastasis. However, the difference and relationship between MTA1 and MTA2 have not been fully elucidated.MethodsTranswell assays were used to assess the roles of MTA1 and MTA2 in the metastasis of ZR-75-30 luminal B breast cancer cells in vitro. Immunoblotting and qRT-PCR were used to evaluate the effect of MTA1 overexpression on MTA2. Proteases that cleave MTA2 were predicted using an online web server. The role of neutrophil elastase (NE) in MTA1 overexpression-induced MTA2 downregulation was confirmed by specific inhibitor treatment, knockdown, overexpression and immunocytochemistry, and NE cleavage sites in MTA2 were confirmed by MTA2 truncation and mutation. The effect of MTA1 overexpression on the intrinsic inhibitor of NE, elafin, was detected by qRT-PCR, immunoblotting and treatment with inhibitors.ResultsMTA1 overexpression inhibited, while MTA2 promoted the metastasis of ZR-75-30 cells in vitro. MTA1 overexpression downregulated MTA2 expression at the protein level rather than the mRNA level. NE was predicted to cleave MTA2 and was responsible for MTA1 overexpression-induced MTA2 degradation. NE was found to cleave MTA2 in the C-terminus at the 486, 497, 542, 583 and 621 sites. MTA1 overexpression activated NE by downregulating elafin in a histone deacetylase- and DNA methyltransferase-dependent manner.ConclusionsMTA1 and MTA2 play opposing roles in the metastasis of ZR-75-30 luminal B breast cancer cells in vitro. MTA1 downregulates MTA2 at the protein level by epigenetically repressing the expression of elafin and releasing the inhibition of neutrophil elastase, which cleaves MTA2 in the C-terminus at multiple specific sites.

Upregulation of circ-UBAP2 predicts poor prognosis and promotes triple-negative breast cancer progression through the miR-661/MTA1 pathway

Recently, a large number of studies have shown that circular RNA (circRNA) is involved in the development and progression of human cancer. However, its role in triple-negative breast cancer (TNBC) remains largely unknown. In this study, a novel circRNA, circ-UBAP2 (hsa_circ_0001846), was shown to be markedly upregulated in TNBC. Moreover, high circ-UBAP2 expression was closely associated with larger tumour size (p = 0.003), advanced TNM stage (p = 0.005), lymph node metastasis (p = 0.002), and unfavourable prognosis (p = 0.0256). Functionally, lentivirus-mediated stable knockdown of circ-UBAP2 dramatically weakened the ability of TNBC cells to proliferate and migrate and induced apoptosis in vitro and in vivo. Regarding the mechanism, we found that circ-UBAP2 was mainly observed in the cytoplasm and was capable of sponging miRNA-661 to increase the expression of the oncogene MTA1. Additionally, silencing of miRNA-661 or overexpression of MTA1 could partially rescue the attenuated malignant phenotype caused by circ-UBAP2 knockdown. Taken together, our data reveal that circ-UBAP2 plays a vital regulatory role in TNBC via the miR-661/MTA1 axis and may serve as a promising therapeutic target for TNBC patients.

Abstract 5107: A novel MTA1 knock-in mouse model for the mechanistic and therapeutic studies of MTA1-driven prostate cancer

Abstract Metastasis-associated protein 1 is known to play role in prostate cancer progression and metastasis. Studies of MTA1-mediated prostate cancer tumorigenesis, progression and metastasis have been hampered by a lack of suitable experimental system. Here we describe a new conditional mouse model that shows strong MTA1 expression in the prostate. This model was generated through MTA1 transgene knocked into the mouse ROSA26 (R26) locus using CAG-LoxP-Stop-LoxP (LSL)-2HA-MTA1-T2A-GFP-pA construct (Applied StemCell,Inc, Menlo Park, CA). Briefly, after generation of a genetically modified founder mouse line Rosa26-3attP, resulted MTA1 transgene embryos were injected into foster mice to produce MTA1 founders, designated as R26-LSL-MTA1. To monitor tumor formation and development in live animals by using IVIS, we have crossbred R26-LSL-MTA1 with Pb-Cre+;Luc and generated transgenic lines that express MTA1 and Luc upon Cre-mediated removal of the LSL cassette, specifically in the prostate epithelium (Pb-Cre+;R26MTA1;R26Luc) (MTA1-tg). We confirmed prostate-specific expression of the MTA1 transgene on mRNA and protein levels. We evaluated prostate histology for differences in histology of control normal prostates (Pb-Cre-; MTA1-tg) and MTA1-tg mice at as early as 13-weeks of age. MTA1 overexpressing prostate showed signs of mPIN characterized by glandular structures composed of atypical proliferating luminal cells that fill out the lumen. We detected differences in cellular proliferation, as determined by increased PCNA and decreased p27 as well as Ki67 immunofluorescent staining in MTA1-tg prostate. Moreover, expression of several oncogenic MTA1-guided molecules was increased in the prostates of MTA1-tg mice. We have previously reported on the role of MTA1-mediated signaling in prostate tumor progression in the prostate-specific Pten heterozygous (Pb-Cre+; Pten+/f) and Pten null (Pb-Cre+; Ptenf/f ) mice. To determine the role of MTA1 overexpression in the context of PTEN loss, we generated MTA1-tg; Pten+/f and MTA1-tg; Ptenf/f mice to evaluate whether MTA1overexpression in the prostate promotes an earlier onset, greater total incidence, accelerated tumor growth rate and metastasis. We predict that MTA1 overexpression will cause higher activation of downstream pathways to promote cancer cell survival, which will result in increased incidence of invasive adenocarcinoma and probably lymph node metastasis. Mice will be sacrificed at different time points for prostate tissue and lymph nodes isolation and subsequent histopathological, immunochemical and molecular evaluation. Citation Format: Avinash Kumar, Swati Dhar, Nasir A. Butt, Pravin R. Phadatare, Kshiti Dholakia, Jogarao Vedula, Virginia Donovan, Anait S. Levenson. A novel MTA1 knock-in mouse model for the mechanistic and therapeutic studies of MTA1-driven prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5107.

Metastasis-associated protein 1 is an upstream regulator of DNMT3a and stimulator of insulin-growth factor binding protein-3 in breast cancer

Despite a recognized role of DNA methyltransferase 3a (DNMT3a) in human cancer, the nature of its upstream regulator(s) and relationship with the master chromatin remodeling factor MTA1, continues to be poorly understood. Here, we found an inverse relationship between the levels of MTA1 and DNMT3a in human cancer and that high levels of MTA1 in combination of low DNMT3a status correlates well with poor survival of breast cancer patients. We discovered that MTA1 represses DNMT3a expression via HDAC1/YY1 transcription factor complex. Because IGFBP3 is an established target of DNMT3a, we investigated the effect of MTA1 upon IGFBP3 expression, and found a coactivator role of MTA1/c-Jun/Pol II coactivator complex upon the IGFBP3 transcription. In addition, MTA1 overexpression correlates well with low levels of DNMT3a which, in turn also correlates with a high IGFBP3 status in breast cancer patients and predicts a poor clinical outcome for breast cancer patients. These findings suggest that MTA1 could regulate the expression of IGFBP3 in both DNMT3a-dependent and -independent manner. Together findings presented here recognize an inherent role of MTA1 as a modifier of DNMT3a and IGFBP3 expression, and consequently, the role of MTA1-DNMT3a-IGFBP3 axis in breast cancer progression.

MTA1 modulated by miR-30e contributes to epithelial-to-mesenchymal transition in hepatocellular carcinoma through an ErbB2-dependent pathway.

MTA1 is a metastasis-associated protein, which is essential to epithelial-to-mesenchymal transition (EMT). However, information concerning its up- and downstream regulation is rare. We investigated its upstream regulation and downstream effector in human hepatocellular carcinoma (HCC). In total, 94 paired HCC and adjacent tissue samples were involved in the study, and the results indicated that decreased miR-30e levels were associated with increased MTA1 levels in human HCC. miR-30e exerted its regulation of MTA1 transcription by binding to its 3'-untranslated region, and was negatively associated with EMT. Furthermore, significantly higher expression of MTA1 was associated with overexpression of v-erb-b2 avian erythroblastic leukemia viral oncogene homolog 2 (ErbB2) in human HCC, and MTA1 can promote transcription of ErbB2 by binding with histone deacetylase 2 (HDAC2) and acting as a promoter. The EMT promotion effect caused by MTA1 largely depended on ErbB2, and reducing the activity of ErbB2 can significantly attenuate EMT promotion by causing overexpression of MTA1 both in vitro and in vivo. In general, downregulation of miR-30e can increase levels of MTA1 in human HCC, and furthermore promote cell invasion and metastasis by promoting ErbB2.

Metastasis-associated protein is a predictive biomarker for metastasis and recurrence in gastric cancer.

The metastasis-associated(MTA) gene family is a critical component of the nucleosome remodeling and histone deacetylase complex, and plays an important role in metastatic processes. We systematically evaluated dysregulation of the MTA family to clarify their clinical significance in gastric cancer(GC). One hundred and forty-five patients who underwent surgery for GC were evaluated. We analyzed the expression levels of the MTA family(MTA1,2 and3) by qPCR in GC tissue, and the MTA1 protein expression in primary cancer and matched normal mucosa(NM) was measured using immunohistochemical analysis. The expression of all the MTA family members was significantly increased in a stage-dependent manner, and elevated expression of all of the MTA family members was correlated with metastatic factors and prognosis in GC patients. Multivariate analysis revealed that MTA1 overexpression was an independent risk factor for survival. Especially, elevated expression of MTA1 was significantly correlated with recurrence, and was an independent risk factor for lymph node metastasis. Immunohistochemical analysis demonstrated that MTA1 was predominantly expressed in the nuclei of primary GC cells but was not expressed in NM and in the cancer stroma. In conclusion, quantification of MTA expression may support the accurate diagnosis of disease staging and may help predict clinical outcomes.

Crosstalk between ATF4 and MTA1/HDAC1 promotes osteosarcoma progression.

The stress response gene activating transcription factor 4 (ATF4) is involved in metastatic behavior and cellular protection. Here we show that ATF4 is upregulated in osteosarcoma (OS) cell lines and patient clinical samples as compared to matched non-tumor tissue. Overexpression of ATF4 in OS cells promoted cell proliferation, migration and lung metastasis. Furthermore, the expression of ATF4 was markedly reduced in metastasis associated protein (MTA1) or histone deacetylase 1 (HDAC1) knockdown OS cells, but MTA1 overexpression increased the stability and activity of ATF4 protein via ATF4 deacetylation by HDAC1. ATF4 in turn enhanced the expression of MTA1 and HDAC1 at the transcription level, suggesting a positive feedback loop between ATF4 and MTA1/HDAC1. Clinically, the level of ATF4 was positively correlated with that of MTA1 in OS. Mice injected with ATF4-overexpressing cells exhibited a higher rate of tumor growth, and the average weight of these tumors was ×90% greater than the controls. Taken together, these data establish a direct correlation between ATF4-induced OS progression and MTA1/HDAC1-associated metastasis, and support the potential therapeutic value of targeting ATF4 in the treatment of OS.

Inhibition of MTA1 by ERα contributes to protection hepatocellular carcinoma from tumor proliferation and metastasis.

BackgroundAlthough expression of MTA1 inversely correlates with the nuclear localization of ERα, the effect and molecular mechanism of ERα regulation of MTA1 remain unknown.MethodsQuantitative real-time PCR and western blot analyses were used to measure levels of MTA1. The effect on HCC cell proliferation and invasion was assessed by EdU incorporation assays and Transwell, respectively. ShRNA and dual-luciferase assays were used to investigate the regulatory relationship between MTA1 and ERα in cell lines.ResultsWe found that MTA1 gene regulation by ERα may be influenced by nuclear corepressors. The MTA1 promoter has three functional ER-element half-sites that lead to decreased MTA1 transcription and expression. ERα overexpression suppressed the proliferation and invasion of hepatocellular carcinoma cells (HCC). In addition, overexpression of MTA1 attenuated ERα-mediated suppression of the proliferation and invasion of HCC cells and tumor formation in vivo. These results suggested feedback regulation between ERα and MTA1. In summary, our results demonstrated that ERα suppressed proliferation and invasion of human HCC cells through downregulation of MTA1 transcription.ConclusionsOur study is an improved description of the mechanisms of the suppressive effect of ERα on HCCs, adding understanding to the gender disparity of HCC progression.

Overexpression of MTA1 promotes invasiveness and metastasis of ovarian cancer cells

To investigate the effect of metastasis-associated gene MTA1 on proliferation and invasion potential of ovarian cancer cell line A2780. The eukaryotic expressing vector pcDNA3. 1-MTA1 was introduced into A2780 cells by gene transfection in vitro. The MTA1 mRNA and protein level in cancer cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and western blot, respectively. The growth activities of cancer cells were detected by trypan blue stain method. The clone formation assay in soft agar was used to observe the proliferation of cancer cells. Wound healing assay and Transwell assay were used to evaluate migration and invasion abilities of cancer cells. And the protein level of bcl-xL in ovarian cancer cells was measured by immunohistochemistry and western blot. The TUNEL assay was performed to study the apoptosis of tumor cells. Seventy-two hours after transfection, the MTA1 expression increased significantly (P<0.01). The up-regulation of MTA1 did not affect the growth activities of cancer cells (P>0.05), but it promoted clone formation, migration and invasion abilities of cancer cells (P<0.01). The cellular expression of bcl-xL increased 65.22%, with a PI value of (71.64±5.96)%. With the up-regulation of MTA1 and bcl-xL level, the apoptotic rate of A2780 cell was decreased. MTA1 gene plays an important role in progression and metastasis of ovarian cancers, which provides an ideal strategy for gene therapy of ovarian cancers.

Abstract 4: Nuclear MTA1 overexpression is associated with aggressive prostate cancer and metastasis in African American men.

Abstract Metastasis-associate protein 1 (MTA1) plays essential role in prostate cancer (PCa) progression and metastasis. We hypothesized that nuclear MTA1 overexpression in primary tumor tissues may provide meaningful information on prediction of poor prognosis, i.e. MTA1 may serve as a prognostic biomarker for aggressive PCa and a predictor of recurrent disease and metastasis. We used tissue microarrays and clinicopathological information of 301 patients (146 Caucasian Americans and 155 African Americans) who underwent prostatectomy in University of Mississippi Medical Center, Jackson, MS and in University of Iowa, Iowa City, IA. We evaluated MTA1 expression by immunohistochemistry with the emphasis on subcellular localization and total staining score, which accounted intensity and frequency. MTA1 was detected in both cytoplasm and nucleus, however exhibited different expression patterns in terms of subcellular localization depending on pathological category of PCa and metastasis. A significant statistical correlation (p=0.063) was observed between MTA1 nuclear staining and localized PCa compared to PIN, reaching more significance with the worst grade (Gleason &amp;gt;7) and metastatic lesions (p&amp;lt;0.006). When analyzed in terms of racial differences, the difference in MTA1 nuclear overexpression between patients with localized PCa was highly significant (p&amp;lt;0.001), with Caucasian Americans showing higher levels of MTA1. However, when stratified by Gleason score, there were substantial differences in MTA1 levels in low grade tumors (Gleason ≤ 7) compared to high grade tumors (Gleason&amp;gt;7) in African Americans and not in Caucasians, indicating that MTA1 may serve as an “ethnic” biomarker for aggressive disease in African Americans. Moreover, there was a tendency for higher MTA1 nuclear staining in recurrent compared to non-recurrent group (n=50), particularly in African Americans (2.3 times difference). In summary, our observation might have clinical relevance in discriminating subset of low grade Gleason≤7 African American patients with low MTA1 expression who will remain recurrent-free from the same subset that have high MTA1 levels indicating possibility to develop more aggressive disease and metastasis. Putting together results of the current study and our previous finding that MTA1 is downregulated by dietary stilbenes we emphasize new perspectives for PCa management in African American men. Citation Format: Steven J. Dias, Xinchaun Zhou, Marina Ivanovic, Michael P. Gailey, Swati Dhar, Zhi He, Alan Penman, Anait S. Levenson. Nuclear MTA1 overexpression is associated with aggressive prostate cancer and metastasis in African American men. [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 4. doi:10.1158/1538-7445.AM2013-4

Down-Regulation of MiR-30c Promotes the Invasion of Non-Small Cell Lung Cancer by Targeting MTA1

Background: The connection between microRNA expression and lung cancer development has been identified in recent literature. However, the mechanism of microRNA has been poorly elucidated in non-small-cell lung cancer (NSCLC). Methods and Results: Comparing with adjacent tissues (n=75), miR-30c has a lower expression in lung cancer specimens (n=75). The knockdown of miR-30c enhanced the invasion of A549 cells; meanwhile, the overexpression of miR-30c could reverse the effect of the knockdown of miR-30c in vitro. A luciferase assay revealed that miR-30c was directly bound to the 3‘-untranslated regions (3‘-UTR) of MTA1. QRT-PCR and western blot shows MTA1 was up-regulated in mRNA and protein levels. The effect taken on the invasion of NSCLC by overexpression of MTA1 works the same as down-regulated miR-30c. Conclusion: miR-30c may play a pivotal role in controlling lung cancer invasion through regulating MTA1in NSCLC.

Nuclear overexpression of metastasis-associated protein 1 correlates significantly with poor survival in nasopharyngeal carcinoma

BackgroundMetastasis-associated protein 1 (MTA1) has been associated with poor prognosis in several malignant carcinomas. The purpose of this study was to investigate the expression and prognostic value of MTA1 in nasopharyngeal carcinoma (NPC).MethodsMTA1 expression was assessed using immunohistochemistry in paraffin-embedded tumor specimens from 208 untreated NPC patients. Cox regression analysis was used to calculate the hazard ratio (HR), 95% confidence interval (CI) and identify independent prognostic factors, and recursive partitioning analysis was used to create a decision tree.ResultsNuclear overexpression of MTA1 was observed in 48.6% (101/208) of the NPC tissues. Nuclear overexpression of MTA1 correlated positively with N classification (P = 0.02), clinical stage (P = 0.04), distant metastasis (P < 0.01) and death (P = 0.01). Additionally, nuclear overexpression of MTA1 correlated significantly with poorer distant metastasis-free survival (DMFS; P <0.01) and poorer overall survival (OS; P < 0.01). MTA1 had prognostic significance in NPC patients with stage II disease, but not stage III or IV disease. Multivariate analysis demonstrated that nuclear overexpression of MTA1 was independently associated with poorer DMFS (HR, 2.05; 95% CI, 1.13–3.72; P = 0.02) and poorer OS (HR, 1.98; 95% CI, 1.09–3.59; P = 0.03). Using recursive partitioning analysis, the NPC patients could be classified with a low, intermediate or high risk of distant metastasis and death, on the basis of clinical stage, age and MTA1 expression.ConclusionThe results of this study suggest that nuclear overexpression of MTA1 correlates significantly with poorer DMFS and poorer OS in NPC. MTA1 has potential as a novel prognostic biomarker in NPC.

Regulation of NF-κB Circuitry by a Component of the Nucleosome Remodeling and Deacetylase Complex Controls Inflammatory Response Homeostasis

The MTA1 coregulator (metastatic tumor antigen 1), a component of the nucleosome remodeling and deacetylase (NuRD) complex, has been intimately linked with human cancer, but its role in inflammatory responses remains unknown. Here, we discovered that MTA1 is a target of inflammation, and stimulation of macrophages with Escherichia coli lipopolysaccharide (LPS) stimulates MTA1 transcription via the NF-kappaB pathway. Unexpectedly, we found that MTA1 depletion in LPS-stimulated macrophages impairs NF-kappaB signaling and expression of inflammatory molecules. MTA1 itself acts as a transcriptional coactivator of inflammatory cytokines in LPS-stimulated macrophages, and in contrast, it acts as a corepressor in resting primary macrophages as its depletion induced cytokine expression. LPS stimulates S-nitrosylation of histone deacetylase 2 (HDAC2) and interferes with its binding to MTA1, which, in turn, resulted in the loss of corepressor behavior of MTA1.HDAC complex in activated macrophages. Consequently, the net levels of inflammatory cytokines in LPS-stimulated macrophages from MTA1(-/-) mice were high compared with wild-type mice. Accordingly, MTA1(-/-) mice were much more susceptible than control mice to septic shock induced by LPS, revealing that MTA1 protects mice from deregulated host inflammatory response. These findings reveal a previously unrecognized, critical homeostatic role of MTA1, both as a target and as a component of the NF-kappaB circuitry, in the regulation of inflammatory responses.

The metastasis-associated gene MTA1 is upregulated in advanced ovarian cancer, represses ERβ, and enhances expression of oncogenic cytokine GRO

The metastasis-associated genes MTA1 and MTA3 are transcriptional repressors with potential effects on cancer. We analyzed the expression of MTA1, MTA3, ERα, ERβ, and E-cadherin in a total of 115 paraffin-embedded ovarian cancer tissues with respect to cancer staging and FIGO grading. Expression of MTA1, but not that of MTA3, was found to be significantly enhanced in ovarian cancer tissues with advanced cancer stages and higher FIGO grading, indicating an important role of MTA1 in the progression of ovarian cancer. To get further insights into the function of MTA1 in ovarian cancer, MTA1-overexpressing cancer cell clones were generated. In vitro, overexpression of exogenous MTA1 in OVCAR-3 cells had no effect on cell proliferation but enhanced the ability of anchorage-independent growth in soft agar colony formation assays. MTA1 overexpression resulted in downregulation of E-cadherin and MTA3 expression and enhanced expression of the transcriptional repressors SNAIL and SLUG. MTA1 further reduced ERβ expression in vitro and inversely correlated with ERβ expression in vivo. Screening for the expression of angiogenic cytokines expressed by ovarian cancer cells revealed MTA1-mediated upregulation of the oncogenic and angiogenic cytokine GRO (growth-regulated oncogene, CXCL1). Thus, in ovarian cancer, MTA1 expression directly and indirectly regulates the expression of several cancer-promoting as well as metastasis-facilitating factors, indicating an important role for MTA1 expression during ovarian cancer progression.

Metastasis tumor antigen 1 is involved in the resistance to heat stress-induced testicular apoptosis

Our previous study documented the expression of Mta1 during spermatogenesis. Here, we present evidence for a possible involvement of Mta1 in the regulation of testicular function, possibly by interacting with p53. A notable decrease of Mta1 expression was revealed at postsurgical day 6, consistent with the previously reported upregualtion of p53 in mouse cryptorchidism. Furthermore, in vitro over-expression of Mta1 could remarkably elevate the resistance capability of spermatogenic tumor cells against heat-induced apoptosis with a marked impairment of p53 expression. These findings indicate that Mta1 may operate as a negative modifier of apoptosis by interacting with p53 during gametogenesis.