Astrocyte elevated gene-1: recent insights into a novel gene involved in tumor progression, metastasis and neurodegeneration

Using the metabolite alterations monitoring the AEG-1 expression level and cell biological behaviour of U251 cell in vitro

Astrocyte elevated gene-1 (AEG-1) is an important oncogene that overexpresses in gliomas and plays a vital role in their occurrence and progression. However, few reports have shown which biomarkers could reflect the level of AEG-1 expression in vivo so far. In recent years, intracellular metabolites monitored by proton magnetic resonance spectroscopy (1H MRS) as non-invasive imaging biomarkers have been applied to the precise diagnosis and therapy feedback of gliomas. Therefore, understanding the correlation between 1H MRS metabolites and AEG-1 gene expression in U251 cells may help to identify relevant biomarkers. This study constructed three monoclonal AEG-1-knockout U251 cell lines using the clustered regularly interspaced short palindromic repeat (CRISPR) /Cas9 technique and evaluated the biological behaviors and metabolite ratios of these cell lines. With the decline in AEG-1 expression, the apoptosis rate of the AEG-1-knockout cell lines increased. At the same time, the metastatic capacities decreased, and the relative contents of total choline (tCho) and lactate (Lac) were also reduced. In conclusion, deviations in AEG-1 expression influence the apoptosis rate and metastasis capacity of U251 cells, which the 1H MRS metabolite ratio could monitor. The tCho/creatinine(Cr) and Lac/Cr ratios positively correlated with the AEG-1 expression and malignant cell behavior. This study may provide potential biomarkers for accurate preoperative diagnosis and future AEG-1-targeting treatment evaluation of gliomas in vivo.

T4 reduces cisplatin resistance by inhibiting AEG-1 gene expression in lung cancer cells

Lung cancer is the most malignant form of cancer and has the highest morbidity and mortality worldwide. Due to drug resistance, the current chemotherapy for lung cancer is not effective and has poor therapeutic effects. Tripchlorolide (T4), a natural extract from the plant Tripterygium wilfordii, has powerful immunosuppressive and antitumour effects and may become a potential therapeutic agent for lung cancer. Therefore, this study aimed to investigate the effect of T4 on reducing chemoresistance in lung cancer cells and to explore the mechanism. 1. A549 and A549/DDP cells were separately transfected with AEG-1 overexpression and AEG-1 knockdown plasmids. A549/DDP cells were divided into the A549/DDP empty group, T4 group, and T4 + AEG-1 overexpression group. A CCK-8 assay was used to evaluate the proliferation of cells in each group. RT–qPCR and Western blotting were used to detect the expression of AEG-1 and MDR-1. Expression of AEG-1 in A549 and A549/DDP cells was positively correlated with cisplatin resistance. When the AEG-1 protein was overexpressed in A549 cells, the lethal effect of cisplatin on A549 cells was attenuated (all P < 0.05). After the AEG-1 protein was knocked down in A549/DDP cells, cisplatin was applied. The lethal effect was significantly increased compared to that in the corresponding control cells (all P < 0.05). AEG-1 protein expression gradually decreased with increasing T4 concentration in A549 and A549/DDP cells. Resistance to cisplatin was reduced after the addition of T4 to A549/DDP cells (P < 0.05), and this effect was enhanced after transfection with the AEG-1 knockdown plasmid. T4 plays an important role in increasing the sensitivity of lung cancer cells to cisplatin.

WTAP-mediated m6A modification of lncRNA DIAPH1-AS1 enhances its stability to facilitate nasopharyngeal carcinoma growth and metastasis

As the most predominant RNA epigenetic regulation in eukaryotic cells, N⁶-methyladenosine (m⁶A) plays a critical role in human tumorigenesis and cancer progression. However, the biological function and molecular mechanism of m⁶A regulation in naso-pharyngeal carcinoma (NPC) remain elusive. Here, we showed that Wilms' tumor 1-associating protein (WTAP) expression was apparently upregulated in NPC, and increased WTAP was associated with poor prognosis. WTAP upregulated in NPC was fine-tuned by KAT3A-mediated H3K27 acetylation. Functionally, WTAP was required for the growth and metastasis of NPC. Mechanistically, lncRNA DIAPH1-AS1 was identified as a bona fide m⁶A target of WTAP. WTAP-mediated m⁶A modification of DIAPH1-AS1 enhanced its stability relying on the m⁶A reader IGF2BP2-dependent pathway. Furthermore, DIAPH1-AS1 acted as a molecular adaptor that promoted MTDH-LASP1 complex formation and upregulated LASP1 expression, ultimately facilitating NPC growth and metastasis. Thus, WTAP-mediated DIAPH1-AS1 m⁶A methylation is required for NPC tumorigenesis and metastasis.

Glioblastoma microenvironment: The stromal interactions

Glioblastomas (GBMs) are the most common primary brain tumors with poor prognosis due to their aggressive growth accompanied by invasive behavior and therapy-resistance. These features promote a high rate of recurrence; therefore, they are largely incurable. One major cause of the incurability is brought about by the intimate relationship of GBM cells with the microenvironment, which supports the tumor growth in various ways by providing a permissive neighborhood. In the tumor microenvironment are glioma stem cells (GSC); endothelial cells (EC) and hypoxic regions; immune cells and immune modulatory cues; astrocytes; neural stem/precursor cells (NPC) and mesenchymal stem cells (MSC). Each cell type contributes to GBM pathology in unique ways; therefore, it is necessary to understand such interactions between GBM cells and the stromal cells in order to establish a through understanding of the GBM pathology. By explaining the contribution of each stromal entity to GBM pathology we aim to draw an interaction map for GBMs and promote awareness of the complexity of the GBM microenvironment.

Genetically regulated expression in late-onset Alzheimer's disease implicates risk genes within known and novel loci

Late-onset Alzheimer disease (LOAD) is highly polygenic, with a heritability estimated between 40 and 80%, yet risk variants identified in genome-wide studies explain only ~8% of phenotypic variance. Due to its increased power and interpretability, genetically regulated expression (GReX) analysis is an emerging approach to investigate the genetic mechanisms of complex diseases. Here, we conducted GReX analysis within and across 51 tissues on 39 LOAD GWAS data sets comprising 58,713 cases and controls from the Alzheimer's Disease Genetics Consortium (ADGC) and the International Genomics of Alzheimer's Project (IGAP). Meta-analysis across studies identified 216 unique significant genes, including 72 with no previously reported LOAD GWAS associations. Cross-brain-tissue and cross-GTEx models revealed eight additional genes significantly associated with LOAD. Conditional analysis of previously reported loci using established LOAD-risk variants identified eight genes reaching genome-wide significance independent of known signals. Moreover, the proportion of SNP-based heritability is highly enriched in genes identified by GReX analysis. In summary, GReX-based meta-analysis in LOAD identifies 216 genes (including 72 novel genes), illuminating the role of gene regulatory models in LOAD.

Expression of astrocyte-elevated gene-1 indicates prognostic value of fluoropyrimidine-based adjuvant chemotherapy in resectable stage III colorectal cancer

It is unclear which prognostic factor such as pathological features and gene mutation are majorly relevant for stage III disease and whether they aid in determining patients who will be benefit from postoperative adjuvant chemotherapy. The expression of astrocyte-elevated gene-1 (AEG-1), thymidylate synthase (TS), excision repair cross-complementation group 1 (ERCC1), epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) was examined to investigate their role in adjuvant chemotherapy for patients with resectable stage III colorectal cancer (CRC). A significant positive correlation was observed between AEG-1, TS, ERCC1, EGFR, and VEGF gene expression levels in CRC cell lines, and low AEG-1 and TS expression were highly sensitive to 5-fluorouracil treatment. Our results showed that AEG-1 expression was high in T4 and caused CRC recurrence or metastasis. Patients with T4, high AEG-1, TS and VEGF expression had a significantly short disease-free survival and overall survival. In multivariate Cox regression analysis, high AEG-1 expression could be an independent prognostic factor indicating poor survival in patients with resectable stage III CRC treated with adjuvant chemotherapy. In conclusion, AEG-1 expression and tumor grade are potential prognostic factors for recurrence and survival in patients with stage III CRC receiving adjuvant fluoropyrimidine-based chemotherapy.

Astrocyte elevated gene-1 (AEG-1): A key driver of hepatocellular carcinoma (HCC)

An array of human cancers, including hepatocellular carcinoma (HCC), overexpress the oncogene Astrocyte elevated gene-1 (AEG-1). It is now firmly established that AEG-1 is a key driver of carcinogenesis, and enhanced expression of AEG-1 is a marker of poor prognosis in cancer patients. In-depth studies have revealed that AEG-1 positively regulates different hallmarks of HCC progression including growth and proliferation, angiogenesis, invasion, migration, metastasis and resistance to therapeutic intervention. By interacting with a plethora of proteins as well as mRNAs, AEG-1 regulates gene expression at transcriptional, post-transcriptional, and translational levels, and modulates numerous pro-tumorigenic and tumor-suppressive signal transduction pathways. Even though extensive research over the last two decades using various in vitro and in vivo models has established the pivotal role of AEG-1 in HCC, effective targeting of AEG-1 as a therapeutic intervention for HCC is yet to be achieved in the clinic. Targeted delivery of AEG-1 small interfering ribonucleic acid (siRNA) has demonstrated desired therapeutic effects in mouse models of HCC. Peptidomimetic inhibitors based on protein-protein interaction studies has also been developed recently. Continuous unraveling of novel mechanisms in the regulation of HCC by AEG-1 will generate valuable knowledge facilitating development of specific AEG-1 inhibitory strategies. The present review describes the current status of AEG-1 in HCC gleaned from patient-focused and bench-top studies as well as transgenic and knockout mouse models. We also address the challenges that need to be overcome and discuss future perspectives on this exciting molecule to transform it from bench to bedside.

A Review of AEG-1 Oncogene Regulating MicroRNA Expression in Colon Cancer Progression

MicroRNAs are a class of small non-coding RNAs that perform a crucial function in posttranscriptional gene regulation. Dysregulation of these microRNAs is associated with many types of cancer progression. In tumorigenesis, downregulated microRNAs might function as a tumour suppressor by repressing oncogenes, whereas overexpressed miRs might function as oncogenes by suppressing tumour suppressor. Similarly, Metadherin (also known as AEG-1/ LYRIC), is an oncogene, the levels of which are found to be very high in various cancers and play a crucial role in the proliferation of cells and invasion. Our review focuses on the study, which shows the alteration of microRNA expression profile and suppression of carcinogenesis when MTDH/AEG-1 is targeted. It summarises the studies where downregulation and upregulation of AEG-1 and microRNAs, respectively, alter the biological functions of the cell, such as proliferation and apoptosis. Studies have reported that AEG-1 can be direct or indirect target of microRNA, which could provide a new-insight to know the underlying molecular mechanism and might contribute to the progress of new therapeutic strategies for the disease.

Significance of BRCA1 expression in breast and ovarian cancer patients with brain metastasis - A multicentre study

PURPOSE

Cerebral metastases develop in 10-30% of patients with breast cancer (BC) and in around 3.3 to 4% of patients with ovarian cancer (OC). The aim of the multicenter study is to investigate the correlation between the expression of estrogen alpha receptors (ERα), progesterone receptors (PR), human epidermal growth factor receptor 2 (HER2), stromal cell-derived factor 1 (SDF1) and its receptor C-X-C chemokine receptor type 4 (CXCR4), breast cancer metastasis suppressor 1 (BRMS1), astrocyte elevated gene 1 (AEG1), depending on the status of BRCA1 protein, in patients suffering from OC and BC with brain metastases.

PATIENTS AND METHODS

The analysis included 51 patients: 29 with BC and 22 with OC, in whom brain metastases were disclosed.

RESULTS

In most patients (65.5% of BC patients and 68.2% of patients with OC tumors) BRCA1 protein loss was found. No correlation was disclosed between the levels of ERα, PR receptors, HER2, SDF1, CXCR4, AEG1, BRMS1 and BRCA1 status, patient age, stage of disease advancement, grade of histological maturity of the cells, presence of metastases to lymph nodes. A statistically significant correlation was disclosed between the negative expression of PR receptors and a high expression of CXCR4 in patients with BC. High values of the AEG1 protein (linked to metastases) were detected alongside a high expression of BRMS1 (a suppressor of metastases).

CONCLUSIONS

Patients with BC and OC and brain metastases have a frequent loss of BRCA1 expression. The role of ERα, PR, HER2, SDF1, CXCR4, AEG1, BRMS1 in metastatic process needs further studies.

Lipopolysaccharide-induced expression of astrocyte elevated gene-1 promotes degeneration and inflammation of chondrocytes via activation of nuclear factor-κB signaling

Osteoarthritis is an inflammatory disease characterized by joint degeneration and inflammation. Astrocyte elevated gene-1 (AEG-1) has been suggested as a novel inflammation-related factor in the pathological processes of various inflammatory diseases. To date, little is known about the role of AEG-1 in osteoarthritis. The aim of the present study was to explore the potential role of AEG-1 in the regulation of lipopolysaccharide-induced apoptosis and inflammation of chondrocytes. The results showed that AEG-1 expression was significantly upregulated in chondrocytes following exposure to lipopolysaccharide. Knockdown of AEG-1 increased the survival and decreased the expression of matrix metalloproteinases in chondrocytes treated with lipopolysaccharide. Moreover, silencing of AEG-1 restricted the lipopolysaccharide-induced production of proinflammatory cytokines. In contrast, AEG-1 overexpression caused opposite effects. Notably, we found that AEG-1 inhibition blocked the lipopolysaccharide-induced activation of nuclear factor-κB signaling through impeding the nuclear translocation of nuclear factor-κB p65 subunit. Additionally, inhibition of nuclear factor-κB partially reversed the AEG-1-mediated promotion of lipopolysaccharide-induced inflammatory injury in chondrocytes. In conclusion, our results demonstrate that inhibition of AEG-1 expression attenuates lipopolysaccharide-induced degeneration and inflammation of chondrocytes through suppressing the activation of nuclear factor-κB signaling. This work therefore highlights a potential role of AEG-1 in the pathogenesis of osteoarthritis, and indicates its potential as a therapeutic target.

miR-384 targets metadherin gene to suppress growth, migration, and invasion of gastric cancer cells

Objective

MicroRNA-384 (miR-384) has been reported to function as a tumor suppressor in multiple cancers; however, its role in gastric cancer (GC) remains unclear.

Methods

We measured expression levels of miR-384 in GC cell lines and in a normal gastric cell line (GES-1). The association between miR-384 and the metadherin gene (MTDH) was assessed by luciferase reporter assay and western blot. The effects of the miR-384/MTDH axis on GC cell behaviors were measured by CCK-8, wound-healing, and transwell invasion assays.

Results

miR-384 was significantly downregulated in GC cell lines compared with normal gastric cells. MTDH was identified as a direct target of miR-384 by bioinformatics analysis, luciferase assay, and western blot. Functional assays demonstrated that miR-384 inhibited GC cell proliferation, migration, and invasion through targeting MTDH.

Conclusion

These results reveal that miR-384 acts as a tumor suppressor in GC and suggest that the miR-384/MTDH axis may be a potential therapeutic target for GC.

Micheliolide ameliorates renal fibrosis by suppressing the Mtdh/BMP/MAPK pathway

Micheliolide (MCL), derived from parthenolide (PTL), is known for its antioxidant and anti-inflammatory effects and has multiple roles in inflammatory diseases and tumours. To investigate its effect on renal disease, we intragastrically administrated DMAMCL, a dimethylamino Michael adduct of MCL for in vivo use, in two renal fibrosis models-the unilateral ureteral occlusion (UUO) model and an ischaemia-reperfusion injury (IRI) model and used MCL in combination with transforming growth factor beta 1 (TGF-β1) on mouse tubular epithelial cells (mTEC) in vitro. The expression of fibrotic markers (fibronectin and α-SMA) was remarkably reduced, while the expression of the epithelial marker E-cadherin was restored after DMAMCL treatment both in the UUO and IRI mice. MCL function in TGF-β1-induced epithelial-mesenchymal transition (EMT) in mTEC was consistent with the in vivo results. Metadherin (Mtdh) was activated in the fibrotic condition, suggesting that it might be involved in fibrogenesis. Interestingly, we found that while Mtdh was upregulated in the fibrotic condition, DMAMCL/MCL could suppress its expression. The overexpression of Mtdh exerted a pro-fibrotic effect by modulating the BMP/MAPK pathway in mTECs, and MCL could specifically reverse this effect. In conclusion, DMAMCL/MCL treatment represents a novel and effective therapy for renal fibrosis by suppressing the Mtdh/BMP/MAPK pathway.

MicroRNA-30a Mediates Cell Migration and Invasion by Targeting Metadherin in Colorectal Cancer

MicroRNAs play critical roles in the occurrence and progression in various cancers including colorectal cancer. Here, we found that microRNA-30a expression was significantly downregulated in colorectal cancer tissues compared to adjacent noncancerous tissues, and the suppression levels of microRNA-30a were significantly associated with tumor differentiation and lymph node metastasis. We also discovered that the expression level of microRNA-30a was inversely proportional to the invasive potential of several colorectal cancer cell lines. Moreover, overexpression of microRNA-30a in colorectal cancer cells inhibited activity of cell migration and invasion. Luciferase reporter assay confirmed metadherin could be a direct target of microRNA-30a, as the overexpression of microRNA-30a decreased metadherin expression at both the protein and messenger RNA levels. Furthermore, the knockdown of metadherin expression in SW620 significantly decreased cell metastasis and invasion. The upregulation of metadherin at the protein level negatively correlated with the expression of microRNA-30a in colorectal cancer tissues, and this upregulation could partially attenuate the effect induced by microRNA-30a. These findings indicate that microRNA-30a may act as a tumor suppressor in colorectal cancer and that microRNA-30a represses cell migration and invasion by decreasing metadherin, highlighting the therapeutic potential of microRNA-30a and metadherin in colorectal cancer treatment.

Silencing the expression of MTDH increases the radiation sensitivity of SKOV3 ovarian cancer cells and reduces their proliferation and metastasis

Ovarian cancer has a high mortality rate among women worldwide. Radiotherapy is considered an effective method of ovarian cancer treatment, however, radioresistance presents a challenge. It is necessary to develop techniques that can increase radiosensitivity in ovarian cancer, and gene therapy is a promising option. The aim of the present study was to investigate the effects of metadherin (MTDH) silencing on the radiosensitivity of ovarian cancer. Ovarian cancer tissues (n=273) and normal ovarian tissues (n=277) were used, as were SKOV3 ovarian cancer cells and the immortalized human ovarian epidermal HOSEpiC cell line. MTT, Transwell and wound-healing assays were performed to assess the proliferation, invasion and migration abilities of the SKOV3 cells. Colony-forming assays and flow cytometry were applied to detect the radiosensitivity and apoptosis of the SKOV3 cells. Nude mouse xenograft models were established to evaluate the effect of MTDH gene silencing on tumor growth and the efficacy of radiotherapy. Ovarian cancer, in tissues and cells, was demonstrated to have a high level of MTDH. Additionally, MTDH silencing was found to significantly inhibit proliferation, migration and invasion, and induce apoptosis in SKOV3 cells, and it was suggested that MTDH depletion significantly increased the sensitivity of the SKOV3 cells to X-ray radiation. MTDH silencing enhanced radiosensitivity and delayed tumor growth in the nude mouse xenograft model. Collectively, the results obtained in the present study suggest the potential role of MTDH silencing as a technique for ameliorating radioresistance in ovarian cancer. The present study provides a promising experimental basis for the improvement of ovarian cancer radiotherapy treatment.

AEG-1 is involved in hypoxia-induced autophagy and decreases chemosensitivity in T-cell lymphoma

Background

This study was to examine the link between astrocyte elevated gene-1 (AEG-1) and hypoxia induced-chemoresistance in T-cell non-Hodgkin’s lymphoma (T-NHL), as well as the underlying molecular mechanisms.

Methods

Expression of AEG-1, LC3-II, and Beclin-1 were initially examined in human T-NHL tissues (n = 30) and normal lymph node tissues (n = 16) using western blot, real-time PCR and immunohistochemistry. Western blot was also performed to analyze the expression of AEG-1, LC3-II, and Beclin-1 in T-NHL cells (Hut-78 and Jurkat cells) under normoxia and hypoxia. Additionally, the proliferation and apoptosis of Hut-78 cells exposed to different concentration of Adriamycin (ADM) in normoxia and hypoxia were evaluated by MTT and Annexin-V FITC/PI staining assay. Finally, the effects of AEG-1 on Hut-78 cells exposed to ADM in hypoxia were assessed by MTT and Annexin-V FITC/PI staining assay, and 3-MA (autophagy inhibitor) was further used to determine the underlying mechanism.

Results

AEG-1, LC3-II and Beclin-1 expression were significantly increased in T-NHL tissues compared with normal tissues. Incubation of Hut-78 and Jurkat cells in hypoxia obviously increased AEG-1, LC3-II and Beclin-1 expression. Hypoxia induced proliferation and reduced apoptosis of Hut-78 cells exposed to ADM. AEG-1 overexpression further increased proliferation and decreased apoptosis of Hut-78 cells exposed to ADM in hypoxia. Moreover, overexpression of AEG-1 significantly inversed 3-MA induced-changes in cell proliferation and apoptosis of Hut-78 cells exposed to ADM in hypoxia.

Conclusions

This study suggested that AEG-1 is associated with hypoxia-induced T-NHL chemoresistance via regulating autophagy, uncovering a novel target against hypoxia-induced T-NHL chemoresistance.

Electronic supplementary material

The online version of this article (10.1186/s10020-018-0033-6) contains supplementary material, which is available to authorized users.

Downregulation of microRNA-216b contributes to glioma cell growth and migration by promoting AEG-1-mediated signaling

Accumulating evidence indicates microRNA-216b (miR-216b) plays an important role in the development and progression of various cancers. However, little is known about the function of miR-216b in gliomas. In this study, we aimed to investigate the expression level and functional significance of miR-216b in gliomas. We found that miR-216b was significantly downregulated in glioma specimens and cell lines. Overexpression of miR-216b suppressed the growth and migration of glioma cells, while miR-216b inhibition showed the opposite effects. Astrocyte elevated gene-1 (AEG-1) was predicted as a potential target gene of miR-216b by bioinformatics analysis. A dual-luciferase reporter assay showed that miR-216b could directly target the 3'-untranslated region of AEG-1. RT-qPCR and western blot analysis showed that miR-216 negatively regulated AEG-1 expression in glioma cells. Correlation analysis revealed an inverse correlation between miR-216b and AEG-1 in clinical glioma specimens. miR-216b also regulated the activation of nuclear factor-κB and Wnt signaling in glioma cells. Moreover, restoration of AEG-1 expression partially reversed the inhibitory effect of miR-216b overexpression on glioma cell growth and migration. Overall, these results revealed a tumor suppressive role of miR-216b in glioma tumorigenesis, and identified AEG-1 as a target gene of miR-216b action. Our study suggests that miR-216b can be potentially targeted for the development of novel therapies for gliomas.

AEG-1 Contributes to Metastasis in Hypoxia-Related Ovarian Cancer by Modulating the HIF-1alpha/NF-kappaB/VEGF Pathway

Objective

Ovarian carcinoma represents one of the deadliest malignancies among female cancer patients. Astrocyte-elevated gene-1 (AEG-1) participates in the ontogenesis of multiple human malignant diseases. Here we evaluated AEG-1, hypoxia-inducible factor- (HIF-) 1α, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and vascular endothelial growth factor (VEGF) amounts in hypoxia induced ovarian carcinoma cells. This study aimed to explore the mechanism by which AEG-1 regulates metastasis in hypoxia induced ovarian carcinoma.

Patients and Methods

AEG-1, HIF-1α, and VEGF protein amounts were evaluated by immunohistochemistry in 40 and 170 normal ovary and ovarian cancer tissue specimens, respectively. In addition, AEG-1, HIF-1α, NF-κB, and VEGF mRNA and protein levels were determined by reverse quantified RT-PCR and WB, respectively, at different time periods (0–24 h) in epithelial ovarian cancer (EOC) SKOV3 cells treated in a hypoxia incubator. Furthermore, NF-κB and VEGF gene and protein expression levels in AEG-1 knockdown EOC cells were quantitated by RT-PCR and WB, respectively.

Results

AEG-1, HIF-1α, and VEGF amounts were significantly elevated in EOC tissue samples compared with normal ovary specimens (p < 0.001). Positive expression of HIF-1α and AEG-1 was associated with higher metastatic rate (p < 0.01), lower FIGO stage (p < 0.001), and degree of differentiation (p < 0.001). Meanwhile, EOC SKOV3 cells grew upon exposure to hypoxia for 8 h (p < 0.001); at this time point, AEG-1, HIF-1α, NF-κB, and VEGF amounts peaked (p < 0.001), at both the gene and the protein levels. After AEG-1 knockdown, HIF-1α, NF-κB, and VEGF amounts were significantly decreased in EOC SKOV3 cells, also under hypoxic conditions (p < 0.01).

Conclusions

As an independent prognostic factor, AEG-1 was found to be significantly associated with hypoxia in ovarian cancer by regulating the HIF-1alpha/NF-kappaB/VEGF pathway. Therefore, AEG-1 may be useful in determining disease stage and prognosis in ovarian cancer.

Silencing of astrocyte elevated gene-1 inhibits proliferation and migration of melanoma cells and induces apoptosis

Melanoma is an aggressive skin malignancy with a high mortality. Astrocyte elevated gene-1 (AEG-1), a downstream target of Ras and c-Myc, has been implicated in the development of multiple tumours, but its role in melanoma remains unclear. In the present study, the role of AEG-1 in melanoma was explored through AEG-1 silencing. Our results showed that silencing AEG-1 inhibited the proliferation of melanoma cells, induced cell cycle arrest, and reduced levels of cyclin A, cyclin B, cyclin D1, cyclin E, and cyclin-dependent kinase 2. AEG-1silencing also induced apoptosis in melanoma cells and altered the levels of cleaved caspase-3, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein. Moreover, silencing AEG-1 suppressed the migration and invasion of melanoma cells, reduced the expressions and activities of matrix metallopeptidase (MMP)-2 and MMP-9, and inhibited the activation of the Wnt/β-catenin signalling pathway in melanoma cells. Furthermore, in vivo experiments revealed that AEG-1 silencing inhibited the growth of melanoma xenografts in nude mice. In summary, our study demonstrates an oncogenic role of AEG-1 in melanoma and suggests that AEG-1 may serve as a potential therapeutic target in the treatment of melanoma.

Nuclear overexpression of the overexpressed in lung cancer 1 predicts worse prognosis in gastric adenocarcinoma

We have performed this retrospective study to elucidate whether elevated expression of the overexpressed in lung cancer 1 (OLC1) was related to the clinicopathological parameters and prognosis of patients with gastric adenocarcinoma. Additionally, different effects of various subcellular OLC1 expression on gastric adeno-carcinogenesis were focused on in our study. Both overall and subcellular expression of OLC1 was evaluated by immunohistochemistry(IHC) via tissue microarrays from total 393 samples. The Kaplan-Meier method and Cox's proportional hazard model were exerted to further explore the correlation between OLC1 and prognosis. Total overexpression of OLC1 was significantly associated with stage (P = 0.004) and differentiation (P = 0.009), and only the strong total expression could predict a poor prognosis (HR = 1.31, P = 0.04). There were significant associations found between nuclear overexpression and tumor invasion depth(P = 0.002), lymph node (P < 0.001), stage (P = 0.004), differentiation (P < 0.001) and smoking history (P = 0.045). Furthermore, over-expressed nuclear OLC1 protein could be an independent risk factor for gastric adenocarcinoma (univariate: HR = 1.43, P = 0.003; multivariate: HR = 1.39, P = 0.011). In general, both total and nuclear overexpression of OLC1 could be the signs of gastric adeno-carcinogenesis, which might be served as the biomarkers for diagnosis at an early stage, even at the onset of tumorigenesis. Rather than the total expression, nuclear overexpression of OLC1 was correlated with most clinicopathological parameters and could predict a poor overall survival as an independent factor for prognosis, which made it a more effective and sensitive biomarker for gastric adenocarcinoma.

Astrocyte Elevated Gene 1 (AEG-1): A Promising Candidate for Molecular Targeted Therapy in Oral Squamous Cell Carcinomas

Background: Astrocyte elevated gene 1 (AEG-1), also known as metadherin, is an oncogene which is overexpressed in various types of cancer, playing important roles in invasion, metastasis, angiogenesis and chemotherapy resistance. Hence it might be used as a therapeutic target. The aim of this study was to evaluate the expression of AEG-1 as a novel molecular marker in oral squamous cell carcinomas and establish correlations with clinicopathologic factors. Materials and Methods: Thirty formalin fixed paraffin-embedded blocks of OSCC cases and 30 samples of normal oral mucosa with minimal inflammation were selected and stained immunohistochemically for AEG-1. Staining intensity and percentage of stained cells were scored according to nuclear and cytoplasmic staining of epithelial cells. Relationship between immunoreactivity and clinicopathologic factors were examined by T-test and Mann-Whitney. Results: AEG-1 expression in OSCCs was greater than in normal oral mucosa (P<0.05). However, nuclear and cytoplasmic expression of AEG-1 was not associated with any of the clinicopathologic factors, age and gender of patients, tumor location, smoking history, tumor staging and grading, metastasis to lymph nodes and distant metastasis ( P>0.05). Conclusion: The current results support some role of AEG-1 in genesis of oral squamous cell carcinomas.

Depletion of astrocyte elevated gene-1 suppresses tumorigenesis through inhibition of Akt activity in bladder cancer cells

Astrocyte elevated gene-1 (AEG-1) has been reported to promote tumorigenesis, however the molecular mechanisms by which AEG-1-induced bladder cancer progression has remained elusive. Here, we identified that depletion of AEG-1 in bladder cancer cells suppressed cell growth. Moreover, we observed that down-regulation of AEG-1 induced apoptosis and inhibited cell migration and invasion. Furthermore, depletion of AEG-1 inhibited Akt activity and suppressed Bcl-2 expression, but upregulated the levels of p21 and p27. Our findings reveal that AEG-1 carries out its oncogenic function via activation of the Akt pathway. Therefore, inhibition of AEG-1 could be a novel treatment approach for bladder cancer.

MicroRNA-384 represses the growth and invasion of non-small-cell lung cancer by targeting astrocyte elevated gene-1/Wnt signaling

Dysregulation of microRNA (miRNA) expression is a critical event in the development and progression of non-small-cell lung cancer (NSCLC). miR-384 has been identified as a novel cancer-related miRNA in numerous cancers, but little is known about its role and functional mechanism in NSCLC. In this study, we found that miR-384 was significantly downregulated in NSCLC tissues and cell lines. The overexpression of miR-384 repressed the growth and invasion of NSCLC cells, whereas its suppression showed the opposite effect. Moreover, astrocyte elevated gene-1 (AEG-1) was identified as a target gene of miR-384. The overexpression of miR-384 significantly decreased AEG-1 expression and Wnt signaling, whereas its suppression promoted this pathway. Furthermore, miR-384 was inversely correlated with AEG-1 expression in NSCLC tissues. Additionally, restoration of AEG-1 expression in miR-384-overexpressing cells significantly reversed the antitumor effects of miR-384. Taken together, these results reveal that miR-384 represses the growth and invasion of NSCLC cells by targeting AEG-1. Our study suggest that miR-384 and AEG-1 may serve as potential targets for the diagnosis and treatment of NSCLC.

Remodeling the blood-brain barrier microenvironment by natural products for brain tumor therapy

Brain tumor incidence shows an upward trend in recent years; brain tumors account for 5% of adult tumors, while in children, this figure has increased to 70%. Moreover, 20%-30% of malignant tumors will eventually metastasize into the brain. Both benign and malignant tumors can cause an increase in intracranial pressure and brain tissue compression, leading to central nervous system (CNS) damage which endangers the patients' lives. Despite the many approaches to treating brain tumors and the progress that has been made, only modest gains in survival time of brain tumor patients have been achieved. At present, chemotherapy is the treatment of choice for many cancers, but the special structure of the blood-brain barrier (BBB) limits most chemotherapeutic agents from passing through the BBB and penetrating into tumors in the brain. The BBB microenvironment contains numerous cell types, including endothelial cells, astrocytes, peripheral cells and microglia, and extracellular matrix (ECM). Many chemical components of natural products are reported to regulate the BBB microenvironment near brain tumors and assist in their treatment. This review focuses on the composition and function of the BBB microenvironment under both physiological and pathological conditions, and the current research progress in regulating the BBB microenvironment by natural products to promote the treatment of brain tumors.

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 3 years (0.4-11.6). The median overall survival was not associated with MTDH status (2.79 years for MTDH-negative and 3.60 years 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.

Astrocyte-elevated gene-1 confers resistance to pemetrexed in non-small cell lung cancer by upregulating thymidylate synthase expression

Previous studies have suggested that astrocyte-elevated gene-1 (AEG-1) contributes to the mechanisms of resistance to various chemotherapeutics. In this study, we investigated whether AEG-1 expression level correlated with that of thymidylate synthase (TS), as higher TS expression is known to be associated with the resistance to pemetrexed chemotherapy in patients with advanced lung adenocarcinoma. Using pemetrexed-resistant lung adenocarcinoma PC-9 cell line, we demonstrated that transfection of AEG-1 siRNA lowered TS expression and decreased pemetrexed IC₅₀ value. In contrast, overexpression of AEG-1 was associated with increased expression of TS and higher pemetrexed IC₅₀ value. Immunohistochemical staining of clinical biopsy samples showed that patients with lower AEG-1 expression had longer overall survival time. Moreover, analysis of repeated biopsy samples revealed that an increase in the TS level from baseline to disease progression was significantly associated with the elevation of AEG-1 expression. In conclusion, our data demonstrated that TS expression might be regulated by AEG-1 and that increased expression of these proteins contributes to lung cancer disease progression and may be associated with the development of resistance to pemetrexed.

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.

Novel Thiosemicarbazones Inhibit Lysine-Rich Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1) Coisolated (LYRIC) and the LYRIC-Induced Epithelial-Mesenchymal Transition via Upregulation of N-Myc Downstream-Regulated Gene 1 (NDRG1)

Tumor necrosis factor α (TNFα) plays a vital role in cancer progression as it is associated with inflammation and promotion of cancer angiogenesis and metastasis. The effects of TNFα are mediated by its downstream target, the oncogene lysine-rich CEACAM1 coisolated protein (LYRIC, also known as metadherin or astrocyte elevated gene-1). LYRIC plays an important role in activating the nuclear factor-ĸB (NF-κB) signaling pathway, which controls multiple cellular processes, including proliferation, apoptosis, migration, etc. In contrast, the metastasis suppressor N-myc downstream regulated gene 1 (NDRG1) has the opposite effect on the NF-κB pathway, being able to inhibit NF-κB activation and reduce angiogenesis, proliferation, migration, and cancer cell invasion. These potent anticancer properties make NDRG1 an ideal therapeutic target. Indeed, a novel class of thiosemicarbazone anticancer agents that target this molecule has been developed; the lead agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone, has recently entered clinical trials for advanced and resistant cancers. To further elucidate the interaction between NDRG1 and oncogenic signaling, this study for the first time assessed the effects of NDRG1 on the tumorigenic properties of TNFα and its downstream target, LYRIC. We have demonstrated that NDRG1 inhibits the TNFα-mediated epithelial-to-mesenchymal transition. Further, NDRG1 also potently inhibited LYRIC expression, with a negative feedback loop existing between these two molecules. Examining the mechanism involved, we demonstrated that NDRG1 inhibited phosphatidylinositol 3-kinase/AKT signaling, leading to reduced levels of the LYRIC transcriptional activator, c-Myc. Finally, we demonstrated that novel thiosemicarbazones that upregulate NDRG1 also inhibit LYRIC expression, further highlighting their marked potential for cancer treatment.

HIF-1α binding to AEG-1 promoter induced upregulated AEG-1 expression associated with metastasis in ovarian cancer

Ovarian cancer with the highest mortality rate among gynecological malignancies is one of common cancers among female cancer patients. As reported in recent years, AEG‐1 was associated with the occurrence, development, and metastasis of ovarian cancer, but the mechanisms remain unclear. In the current study, invasion capabilities of ovarian cancer OVCAR3 cells were measured by viral infection and transwell assay. Western blot analysis was used to evaluate the expression levels of β‐catenin, E‐cadherin, MMP2, and MMP9. With qRT‐PCR analysis, AEG‐1 and HIF‐1α gene expression were detected. We used luciferase reporter gene to measure AEG‐1 promoter activity under normoxia/hypoxia in OVCAR3 cells. Our work demonstrated that AEG‐1 significantly enhanced invasion capabilities of OVCAR3 cells and the expression levels of β‐catenin, E‐cadherin, MMP2, and MMP9 associated with invasion capabilities of OVCAR3 cells were upregulated. Furthermore, hypoxia enhanced invasion capabilities of OVCAR3 cells and induced AEG‐1 high gene expression, which was reversed by AEG‐1 knockdown lentivirus. HIF‐1α expression upregulation was induced in OVCAR3 cells after hypoxia. HIF‐1α knockdown lentivirus induced downregulated expression of AEG‐1 and invasion capabilities of OVCAR3 cells were also inhibited. Wild‐type AEG‐1 promoter activity under hypoxic conditions was significantly higher than that AEG‐1 mutation under normoxic conditions in the absence of hypoxia response. Our results suggested that HIF‐1α binds to AEG‐1 promoter to upregulate its expression, which was correlated with metastasis in ovarian cancer by inducing the expression of MMP2 and MMP9 as well as inhibiting expression of E‐cadherin and β‐catenin.

MicroRNA-342-3p Inhibits the Proliferation, Migration, and Invasion of Osteosarcoma Cells by Targeting Astrocyte-Elevated Gene-1 (AEG-1)

Recent studies suggest that microRNAs (miRNAs) are critical regulators in many types of cancer, including osteosarcoma. miR-342-3p has emerged as an important cancer-related miRNA in several types of cancers. However, the functional significance of miR-342-3p in osteosarcoma is unknown. The aims of this study were to investigate whether miR-342-3p is dysregulated in osteosarcoma and to explore the biological function of miR-342-3p in regulating cellular processes of osteosarcoma cells. We found that miR-342-3p expression was significantly decreased in osteosarcoma tissues and cell lines. Overexpression of miR-342-3p inhibits the proliferation, migration, and invasion of osteosarcoma cells. In contrast, the inhibition of miR-342-3p exhibited the opposite effect. Astrocyte-elevated gene-1 (AEG-1) was identified as one of the target genes of miR-342-3p in osteosarcoma cells by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. Overexpression of miR-342-3p also inhibited the Wnt and nuclear factor κB signaling pathways. Moreover, overexpression of AEG-1 partially rescued the inhibitory effects of miR-342-3p mediated on the proliferation, migration, and invasion of osteosarcoma cells. Overall, our results show that miR-342-3p inhibits the proliferation, migration, and invasion of osteosarcoma cells through targeting AEG-1, suggesting a potential target for the development of miRNA-based therapy for osteosarcoma.

Zfra restores memory deficits in Alzheimer's disease triple-transgenic mice by blocking aggregation of TRAPPC6AΔ, SH3GLB2, tau, and amyloid β, and inflammatory NF-κB activation

Introduction

Zinc finger-like protein that regulates apoptosis (Zfra) is a naturally occurring 31-amino-acid protein. Synthetic peptides Zfra1–31 and Zfra4–10 are known to effectively block the growth of many types of cancer cells.

Methods

Ten-month-old triple-transgenic (3×Tg) mice for Alzheimer's disease (AD) received synthetic Zfra peptides via tail vein injections, followed by examining restoration of memory deficits.

Results

Zfra significantly downregulated TRAPPC6AΔ, SH3GLB2, tau, and amyloid β (Αβ) aggregates in the brains of 3×Tg mice and effectively restored their memory capabilities. Zfra inhibited melanoma-induced neuronal death in the hippocampus and plaque formation in the cortex. Mechanistically, Zfra blocked the aggregation of amyloid β 42 and many serine-containing peptides in vitro, suppressed tumor necrosis factor–mediated NF-κB activation, and bound cytosolic proteins for accelerating their degradation in ubiquitin/proteasome-independent manner.

Discussion

Zfra peptides exhibit a strong efficacy in blocking tau aggregation and amyloid Αβ formation and restore memory deficits in 3×Tg mice, suggesting its potential for treatment of AD.

Cytotoxic Effects of Environmental Toxins on Human Glial Cells

Toxins produced by cyanobacteria and dinoflagellates have increasingly become a public health concern due to their degenerative effects on mammalian tissue and cells. In particular, emerging evidence has called attention to the neurodegenerative effects of the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA). Other toxins such as the neurotoxins saxitoxin and ciguatoxin, as well as the hepatotoxic microcystin, have been previously shown to have a range of effects upon the nervous system. However, the capacity of these toxins to cause neurodegeneration in human cells has not, to our knowledge, been previously investigated. This study aimed to examine the cytotoxic effects of BMAA, microcystin-LR (MC-LR), saxitoxin (STX) and ciguatoxin (CTX-1B) on primary adult human astrocytes. We also demonstrated that α-lipoate attenuated MC-LR toxicity in primary astrocytes and characterised changes in gene expression which could potentially be caused by these toxins in primary astrocytes. Herein, we are the first to show that all of these toxins are capable of causing physiological changes consistent with neurodegeneration in glial cells, via oxidative stress and excitotoxicity, leading to a reduction in cell proliferation culminating in cell death. In addition, MC-LR toxicity was reduced significantly in astrocytes-treated α-lipoic acid. While there were no significant changes in gene expression, many of the probes that were altered were associated with neurodegenerative disease pathogenesis. Overall, this is important in advancing our current understanding of the mechanism of toxicity of MC-LR on human brain function in vitro, particularly in the context of neurodegeneration.

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.

AEG-1/MTDH/LYRIC: A Promiscuous Protein Partner Critical in Cancer, Obesity, and CNS Diseases

Since its original discovery in 2002, AEG-1/MTDH/LYRIC has emerged as a primary regulator of several diseases including cancer, inflammatory diseases, and neurodegenerative diseases. AEG-1/MTDH/LYRIC has emerged as a key contributory molecule in almost every aspect of cancer progression, including uncontrolled cell growth, evasion of apoptosis, increased cell migration and invasion, angiogenesis, chemoresistance, and metastasis. Additionally, recent studies highlight a seminal role of AEG-1/MTDH/LYRIC in neurodegenerative diseases and obesity. By interacting with multiple protein partners, AEG-1/MTDH/LYRIC plays multifaceted roles in the pathogenesis of a wide variety of diseases. This review discusses the current state of understanding of AEG-1/MTDH/LYRIC regulation and function in cancer and other diseases with a focus on its association/interaction with several pivotal protein partners.

Genetic insights into migraine and glutamate: a protagonist driving the headache

Migraine is a complex polygenic disorder that continues to be a great source of morbidity in the developed world with a prevalence of 12% in the Caucasian population. Genetic and pharmacological studies have implicated the glutamate pathway in migraine pathophysiology. Glutamate profoundly impacts brain circuits that regulate core symptom domains in a range of neuropsychiatric conditions and thus remains a "hot" target for drug discovery. Glutamate has been implicated in cortical spreading depression (CSD), the phenomenon responsible for migraine with aura and in animal models carrying FHM mutations. Genotyping case-control studies have shown an association between glutamate receptor genes, namely, GRIA1 and GRIA3 with migraine with indirect supporting evidence from GWAS. New evidence localizes PRRT2 at glutamatergic synapses and shows it affects glutamate signalling and glutamate receptor activity via interactions with GRIA1. Glutamate-system defects have also been recently implicated in a novel FHM2 ATP1A2 disease-mutation mouse model. Adding to the growing evidence neurophysiological findings support a role for glutamate in cortical excitability. In addition to the existence of multiple genes to choreograph the functions of fast-signalling glutamatergic neurons, glutamate receptor diversity and regulation is further increased by the post-translational mechanisms of RNA editing and miRNAs. Ongoing genetic studies, GWAS and meta-analysis implicate neurogenic mechanisms in migraine pathology and the first genome-wide associated locus for migraine on chromosome X. Finally, in addition to glutamate modulating therapies, the kynurenine pathway has emerged as a candidate for involvement in migraine pathophysiology. In this review we discuss recent genetic evidence and glutamate modulating therapies that bear on the hypothesis that a glutamatergic mechanism may be involved in migraine susceptibility.

Role of HCP5-miR-139-RUNX1 Feedback Loop in Regulating Malignant Behavior of Glioma Cells

Aberrant expression of long noncoding RNAs has recently been reported in tumorigenesis and plays a pivotal role in regulating malignant behavior of cancers. In this study, we confirmed that the long noncoding RNAs human histocompatibility leukocyte antigen (HLA) complex P5 (HCP5) was up-regulated in glioma tissues as well as in U87 and U251 cells. Knockdown of HCP5 inhibited the malignant biological behavior of glioma cells by reducing proliferation, migration and invasion, and inducing apoptosis. HCP5 regulated the malignant behavior of glioma cells by binding to microRNA-139, which functions as a tumor suppressor. Moreover, knockdown of HCP5 down-regulated Runt-related transcription factor 1, a direct and functional downstream target of microRNA-139 that is involved in microRNA-139-mediated tumor-suppressive effects in glioma cells. Runt-related transcription factor 1 increased promoter activities and upregulated expression of the oncogenic gene astrocyte elevated gene-1 (AEG-1). Runt-related transcription factor 1 also increased the promoter activities and expression of HCP5, which showed a positive feedback loop in regulating the malignant behavior of glioma cells. In conclusion, this study demonstrated that the HCP5-microRNA-139- Runt-related transcription factor 1 feedback loop plays a pivotal role in regulating the malignant behavior of glioma cells, which may provide a potential therapeutic strategy for treating glioma.

DYT-40, a novel synthetic 2-styryl-5-nitroimidazole derivative, blocks malignant glioblastoma growth and invasion by inhibiting AEG-1 and NF-κB signaling pathways

Astrocyte elevated gene-1 (AEG-1) has been explored as a novel target for human glioma therapy, thus reflecting its potential contribution to gliomagenesis. In the present study, we investigated the effect of DYT-40, a novel synthetic 2-styryl-5-nitroimidazole derivative, on cell growth and invasion in glioblastoma (GBM) and uncovered the underlying mechanisms of this molecule. DYT-40 induces the intrinsic mitochondrial pathway of apoptosis and inhibits the epithelial-mesenchymal transition (EMT) and invasion of GBM cell lines. Furthermore, DYT-40 deactivates PI3K/Akt and MAPK pathways, suppresses AEG-1 expression, and inhibits NF-κB nuclear translocation. DYT-40 reduced the tumor volumes in a rat C6 glioma model by apoptotic induction. Moreover, HE staining demonstrated that the glioma rat model treated with DYT-40 exhibited better defined tumor margins and fewer invasive cells to the contralateral striatum compared with the vehicle control and temozolomide-treated rats. Microscopic examination showed a decrease in AEG-1-positive cells in DYT-40-treated rats compared with the untreated controls. DYT-40-treatment increases the in vivo apoptotic response of glioma cells to DYT-40 treatment by TUNEL staining. In conclusion, the inhibitory effects of DYT-40 on growth and invasion in GBM suggest that DYT-40 might be a potential AEG-1 inhibitor to prevent the growth and motility of malignant glioma.

Silencing of the metastasis-linked gene, AEG-1, using siRNA-loaded cholamine surface-modified gelatin nanoparticles in the breast carcinoma cell line MCF-7

Cholamine surface-modified gelatin nanoparticles prepared by the double desolvation method using acetone as a dehydrating agent were selected and potentially evaluated as non viral vectors of siRNA targeting a metastatic gene AEG-1 in MCF-7 breast carcinoma cells. The ability of modified gelatin nanoparticle to complex and deliver siRNA for gene silencing was investigated. Hence, Particle size, surface charge (zeta potential) and morphology of siRNA/Gelatin nanoparticles (siGNPs) were characterized via dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Moreover, the nanoparticles cytotoxicity, loading efficiency and interaction with MCF-7 human breast carcinoma cells were evaluated. Cationized GNPs of mean size range of 174nm and PDI of 0.101 were produced. The loading efficiency of siGNPs at a Nitrogen/Phosphate (N/P) ratio (w/w) of 200:1 was approximately 96%. Cellular uptake was evaluated after FITC conjugation where the particles produced high transfection efficiency. Finally, ELISA analysis of AEG-1/MTDH expression demonstrated the gene silencing effect of siGNPs, as more than 75% MTDH protein were inhibited. Our data indicate that cholamine modified GNPs pose a promising non-viral siRNA carrier for altering gene expression in MCF-7 breast cancer cells with many advantages such as relatively high gene transfection efficiency and efficient silencing ability.

Metadherin regulates epithelial-mesenchymal transition in carcinoma

Metadherin (MTDH) was first identified in primary human fetal astrocytes exposed to HIV-1 in 2002 and then recognized as an important oncogene mediating tumorigenesis, progression, invasiveness, and metastasis of carcinomas. Epithelial–mesenchymal transition (EMT) is a vital process in embryonic development, organ repair, and cancer progression. MTDH and EMT have also been proved to be related to the prognosis of patients with cancers. Recent studies reveal a relationship between MTDH overexpression and EMT in some malignancies. This review highlights the overexpression of MTDH and EMT in cancers and their correlations in clinical studies. Positive correlations have been established between MTDH and mesenchymal biomarkers, and negative correlations between MTDH and epithelial biomarkers have also been established. Furthermore, experiments reveal EMT regulated by MTDH, and some signal pathways have been established. Some anticancer drugs targeting MTDH and EMT are introduced in this review. Some perspectives concerning EMT regulation by MTDH are also presented in this review.

Lentivirus-Mediated Knockdown of Astrocyte Elevated Gene-1 Inhibits Growth and Induces Apoptosis through MAPK Pathways in Human Retinoblastoma Cells

Purpose

To explore expression and function of astrocyte elevated gene-1 (AEG-1) in human retinoblastoma (RB).

Methods

The expression of AEG-1 in histological sections of human RBs and in RB cell lines was examined using immunohistochemical staining and RT-PCR and Western blotting respectively. We knocked down AEG-1 gene levels by AEG-1-siRNA lentivirus transfection of human RB cell lines SO-RB50 and Y79, and using an MTT assay, we assessed the role of AEG-1 on RB cell proliferation. The biological significance of lentivirus transfection induced AEG-1 down-regulation was examined by assessing the apoptosis rate in the transfected RB cells by Annexin V-APC staining and flow cytometry. We additionally measured the expression of Bcl-2, Bax, cleaved-caspase-3 and caspase-3, and the phosphorylation and non-phosphorylation alternation of MAPKs.

Results

AEG-1 expression was detected to be strongly positive in the histological slides of 35 out of 54 (65%) patients with RB. AEG-1 expression increased significantly (P<0.05) with tumor stage. In the RB cell lines SO-RB50, Y79 and WERI-RB1 as compared with retinal pigment epithelium cells, expression of AEG-1 mRNA and AEG-1 protein was significantly higher. In AEG-1-siRNA lentivirus transfected cell cultures as compared with negative control lentivirus transfected cell cultures, levels of AEG-1 mRNA and of AEG-1 protein (P<0.05) and cell growth rates (P<0.01) were significantly lower, and apoptosis rate (P<0.001), Bax/Bcl-2 ratio and cleaved-caspase-3 protein level were significantly increased. The P-ERK/ERK ratio was significantly decreased in the AEG-1-siRNA lentivirus transfected cell lines.

Conclusions

Expression of AEG-1 was associated with RB, in histological slides of patients and in cell culture experiments. Lentivirus transfection induced knockdown of AEG-1 had a tumor suppressive effect, potentially by tumor cell apoptosis induction through inhibition of ERK.

AEG-1 participates in high glucose-induced activation of Rho kinase and epithelial-mesenchymal transition in proximal tubular epithelial cells

OBJECTIVE

To prove whether astrocyte elevated gene-1 (AEG-1) plays a role in high glucose-stimulated Rho kinase activation and epithelial-mesenchymal transition (EMT) in human renal tubular epithelial (HK-2) cells.

METHODS

The protein levels of AEG-1, alpha-smooth muscle actin, E-cadherin and MYPT1 were determined by Western blot.

RESULTS

AEG-1 protein level was upregulated in HK-2 cells stimulated with high glucose. AEG-1 siRNA downregulated Rho kinase protein expression and blocked high glucose-induced EMT.

CONCLUSIONS

Our results show that AEG-1 acts a key role in high glucose-induced activation of Rho kinase and EMT in HK-2 cells.

MicroRNA-377 inhibits non-small-cell lung cancer through targeting AEG-1

Non-small-cell lung cancer (NSCLC) is the leading cause of cancer-related deaths. MicroRNAs (miRNAs) have been reported to be involved in tumorigenesis. However, the underlying mechanisms of microRNA-377 (miR-377) in NSCLC remain unknown. Hence, in the present study, we aimed to explore the role of miR-377 in the development of NSCLC, with identifying its target genes. The results showed that miR-377 expression was significantly decreased in NSCLC tissues as well as in NSCLC cell lines. Moreover, high expression of miR-377 could markedly inhibit the viability, proliferation, migration and invasion of NSCLC cells. The bioinformatics analysis results showed that astrocyte elevated gene-1 (AEG-1), an oncogene as previously reported, was a potential target gene of miR-377, which was further validated by dual-luciferase reporter assay. Besides, the expression of AEG-1 in protein level was decreased by miR-377 overexpression, but not in mRNA level. In addition, AEG-1 overexpression could reverse the inhibitory effects on NSCLC cells caused by miR-377 transfection. In conclusion, our results suggested that miR-377 played an important role in the development of NSCLC by regulating AEG-1 and may be a potential therapeutic target for NSCLC.

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.

The role of AEG-1 in the development of liver cancer

AEG-1 is an oncogene that is overexpressed in all cancers, including hepatocellular carcinoma. AEG-1 plays a seminal role in promoting cancer development and progression by augmenting proliferation, invasion, metastasis, angiogenesis and chemoresistance, all hallmarks of aggressive cancer. AEG-1 mediates its oncogenic function predominantly by interacting with various protein complexes. AEG-1 acts as a scaffold protein, activating multiple protumorigenic signal transduction pathways, such as MEK/ERK, PI3K/Akt, NF-κB and Wnt/β-catenin while regulating gene expression at transcriptional, post-transcriptional and translational levels. Our recent studies document that AEG-1 is fundamentally required for activation of inflammation. A comprehensive and convincing body of data currently points to AEG-1 as an essential component critical to the onset and progression of cancer. The present review describes the current knowledge gleaned from patient and experimental studies as well as transgenic and knockout mouse models, on the impact of AEG-1 on hepatocarcinogenesis.

The expression of astrocyte elevated gene-1 in human non-small-cell lung cancer and its relationship with postoperative chemotherapy and radiotherapy

AIMS

To examine the expression of astrocyte elevated gene-1 (AEG-1) in non-small-cell lung cancer (NSCLC) and analyse the correlation between AEG-1 expression and the prognosis of the patients, particularly the relationship between AEG-1 expression and postoperative chemotherapy and radiotherapy.

METHODS

The expression of AEG-1 was analysed by immunohistochemistry in 225 primary NSCLC specimens and 42 adjacent normal lung tissue specimens. Statistical analyses were performed to evaluate the correlation between AEG-1 expression and the clinicopathological characteristics of the patients as well as the predictive value of AEG-1.

RESULTS

The expression of AEG-1 was associated with the pathological stage (P < 0.001) and lymph node status (P = 0.028). A multivariate analysis indicated that AEG-1 expression was an independent prognostic factor for both overall survival (OS) and disease-free survival (DFS). In the postoperative chemotherapy group, the OS (P = 0.014) and DFS (P = 0.009) in the low AEG-1 expression group were longer than the survival times in the high AEG-1 expression group. In the postoperative radiotherapy group, the local recurrence-free survival was significantly shorter in patients whose tumours showed high AEG-1 expression (P = 0.016).

CONCLUSIONS

AEG-1 expression could be a predictor for OS and DFS in NSCLC patients. Patients with low AEG-1 expression received the greatest benefit from both postoperative chemotherapy and radiotherapy.