Astrocyte Elevated Gene-1 Expression Research Articles

In vitro regulation of hepatocellular carcinoma cell viability, apoptosis, invasion, and AEG-1 expression by LY294002

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world, and is characterized by advanced clinical stages at diagnosis and very poor prognosis. This study investigated the effects of PI3K inhibitor, LY294002, on suppression of astrocyte elevated gene-1 (AEG-1) and regulation of HCC cell viability, apoptosis, and invasion in vitro. Cell lines derived from normal liver and HCC were treated with LY294002 and evaluated by RT-PCR, western blot, cell viability, migration, and invasion assays. The data showed that AEG-1 mRNA and protein were overexpressed in HCC cells, compared to the normal liver cells. LY294002 treatment of HCC cells significantly reduced tumor cell viability, but promoted apoptosis. Tumor cell migration and invasion assays showed that LY294002 treatment also decreased the capacity of HCC cell migration and invasion. Molecularly, LY294002 treatment down-regulated AEG-1 expression, AKT and GSK3β phosphorylation, and expression of cyclinD1, CDK4, VEGF and Bcl2, but up-regulated Bax and c-Myc expression. The data from this study demonstrated usefulness of LY294002 for effective control of HCC. Future studies should investigate the effects of LY294002 on HCC cells in vivo before initiating clinical trials in HCC patients.

Overexpression of astrocyte-elevated gene-1 is associated with cervical carcinoma progression and angiogenesis

Astrocyte-elevated gene-1 (AEG-1) is implicated in the oncogenesis and angiogenesis of various types of human cancers. However, the biological roles of AEG-1 in cervical carcinoma remain to be further elucidated. In the present study, we demonstrated that the expression of AEG-1 was markedly upregulated in the cervical carcinoma cell lines HeLa, CaSki and SiHa, as well as in 8 paired primary cervical carcinoma tissue (CCT) specimens at both the transcriptional and translational levels when compared with normal cervical epithelial cells (NCECs). Furthermore, immunohistochemical (IHC) analysis demonstrated that 180 of 200 (90%) archived CCT specimens exhibited positive staining for AEG-1, and statistical analysis revealed that the upregulation of AEG-1 was significantly correlated with the clinical staging of the patients (P=0.034), including T (P=0.019), N (P=0.038) and M classification (P=0.018) as well as tumor differentiation (P=0.043). Furthermore, loss‑ and gain‑of‑function results showed that knockdown of AEG-1 expression by specific shRNA not only inhibited SiHa cell proliferation and invasive ability, but also significantly decreased the expression of the angiogenesis-related genes HIF-1α, Tie2, VEGF and TEM1/CD248. Moreover, an increased vascular formation ability was observed in human umbilical vein endothelial cells (HUVECs) co-cultured with conditioned medium both from SiHa cells and NCECs transfected with ectopic AEG-1. In conclusion, these results suggest that elevated expression of AEG-1 plays an important role in the aggressiveness and angiogenesis of cervical carcinoma and that AEG‑1 represents a novel and valuable predictive factor for the prognostic evaluation of cervical carcinoma patients.

Ursolic acid inhibits epithelial–mesenchymal transition by suppressing the expression of astrocyte-elevated gene-1 in human nonsmall cell lung cancer A549 cells

Lung cancer is one of the most death-related cancers worldwide. Ursolic acid (UA), a pentacyclic triterpene acid, has a wide range of anticancer functions such as proapoptosis, antiangiogenesis, and antimetastasis. This study was carried out to explore the inhibition mechanism of UA on metastasis of lung cancer A549 cells. First, we found that UA inhibited the metastasis of lung cancer cells in a concentration-dependent manner through an adhesion assay, a cell wound healing assay, and a transwell migration assay in vitro. In addition, after treatment with UA, the A549 cells showed decreased expression of astrocyte-elevated gene-1 (AEG-1) accompanied by upregulation of E-cadherin and downregulation of N-cadherin and vimentin, which have been reported to characterize the epithelial-mesenchymal transition (EMT). Further results also confirmed that the expression of vimentin was decreased by the siRNA technique to directly knock down AEG-1 expression, indicating that AEG-1 was involved in UA-mediated EMT inhibition. Furthermore, our results showed that UA suppressed the expression level of AEG-1 by repressing nuclear factor-κB signaling. Altogether, UA inhibited the EMT by suppressing the expression of AEG-1, correlating with inhibition of nuclear factor-κB in A549 cells. These findings suggested that UA was a potent anti-lung cancer agent, and it may be able to prevent invasion and metastasis of lung cancer cells.

AEG‐1 participates in TGF‐beta1‐induced EMT through p38 MAPK activation

Epithelial-mesenchymal transition (EMT) is an important cellular event in organogenesis, cancer and renal tubulointerstitial fibrosis. Transforming growth factor-beta1 (TGF-beta1) is the key inducer of EMT and the p38 mitogen-activated protein kinases (p38 MAPK), an major intracellular signal transduction pathway is involved in TGF-beta1-induced EMT. Astrocyte elevated gene-1 (AEG-1) represents an chief genetic determinant regulating multiple events in tumorigenesis. Our present study is to explore the role of AEG-1 in TGF-beta1-induced p38 MAPK activation and EMT process in human renal tubular epithelial (HK-2) cells. The protein expressions of AEG-1, the markers of EMT and p38 phosphorylation were measured by Western blot. The protein expression of AEG-1 was increased in HK-2 cells treated with TGF-beta1. Knockdown of AEG-1 potently inhibited phosphorylation of p38 MAPK and reversed TGF-beta1-induced EMT. Over-expression of AEG-1 via AEG-1 transfection elicited p38 MAPK phosphorylation and promoted EMT. The effects of AEG-1 during EMT were blocked by a p38-specific inhibitor. Our findings suggest that AEG-1 plays an important role in TGF-beta1-induced EMT through activation of p38 MAPK in proximal tubular epithelial cells.

Abstract 5437: Astrocyte Elevated Gene-1 (AEG-1) interacts with retinoid X receptor (RXR) and abrogates its function.

Abstract The oncogene Astrocyte Elevated Gene-1 (AEG-1), also known as Metadherin (MTDH), is overexpressed in a diverse array of cancers, including hepatocellular carcinoma (HCC), and plays an important role in promoting tumor development and progression. Protein-protein interaction predominantly mediates the tumor promoting effects of AEG-1. We now describe screening of a human liver cDNA library by yeast two hybrid assay resulting in identification of Retinoid X Receptor (RXR) as an AEG-1-interacting protein. Site-directed mutagenesis assays identified an LXXLL motif in the N-terminus of AEG-1 mediating interaction with RXR. We employed human HCC cell lines stably overexpressing AEG-1 or with knockdown of AEG-1 and mouse hepatocytes isolated from a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG-1) and from AEG-1 knockout (AEG-1 KO) mouse for our studies. Luciferase reporter assays in these cells demonstrate that AEG-1 profoundly inhibits RXR-mediated transcriptional regulation of its heterodimer partner, such as Retinoic Acid Receptor (RAR), Thyroid Hormone Receptor (TR), Liver X Receptor (LXR) and Peroxisome Proliferator-Activated Receptor (PPAR), in the presence or absence of their corresponding ligands. In this study, we focus on retinoic acid (RA) and thyroid hormone (T3) function. AEG-1 markedly inhibits expression of RA- and T3-induced genes. Overexpressed AEG-1 in cancer cells and in transgenic hepatocytes accumulates in the cytoplasm and inhibits RXR function by trapping RXR in the cytoplasm precluding its nuclear translocation. Additionally, AEG-1 induces phosphorylation of RXR, via ERK and p38 MAPK pathways. Phosphorylated RXR has low transcriptional activity, functions as dominant negative inhibitor of RXR and might facilitate hepatocarcinogenesis by AEG-1. Indeed, chromatin immunoprecipitation (ChIP) assay using RA-target genes, RARB and HOXA1, shows decreased DNA binding of RXR, even upon ligand-treatment. Overexpression of AEG-1 significantly protects human HCC cells, mouse hepatocytes and human promyelocytic leukemia cells from the killing effects of retinoic acid and its synthetic analogs. By inhibiting the expression of T3-regulated gene type I deiodinase (DIO1), AEG-1 abrogates peripheral conversion of inactive T4 to active T3 which is reflected by significantly low T3 level in the circulation of Alb/AEG-1 mice compared to WT mice. Since AEG-1 is upregulated in a wide-variety of cancers it might play an important role in regulating a diverse array of RXR-dependent signaling pathways that are critical for regulating the oncogenic process. Synthetic retinoids are being evaluated as chemopreventive agents for HCC as well as a therapeutic modality for PML. AEG-1 expression level might determine the sensitivity of the patients to these retinoids. Additionally AEG-1 might play a key role in ‘low T3 syndrome’ associated with cancer. Citation Format: Jyoti Srivastava, Chadia L. Robertson, Rachel Gredler, Ayesha Siddiq, Devaraja Rajasekaran, Prasanna K. Santhekadur, Paul B. Fisher, Devanand Sarkar. Astrocyte Elevated Gene-1 (AEG-1) interacts with retinoid X receptor (RXR) and abrogates its function. [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 5437. doi:10.1158/1538-7445.AM2013-5437

AEG-1 overexpression is essential for maintenance of malignant state in human AML cells via up-regulation of Akt1 mediated by AURKA activation

Acute myeloid leukemia (AML) remains highly fatal, highlighting the need for improved understanding of signal pathways that can lead to the development of new therapeutic regimens targeting common molecular pathways shared across different AML subtypes. Here we demonstrate that astrocyte elevated gene-1 (AEG-1) is one of such pathways, involving in cell cycle and apoptosis regulation and contributing to enhanced proliferation and chemoresistance in HL-60 and U937 AML cells. The pleiotropic effects of AEG-1 on AML were found to correlate with two novel target genes, Aurora kinase A (AURKA) and Akt1. Down-regulation of AEG-1 by short-hairpin RNA (shRNA) could not only decrease AURKA expression both on mRNA and protein levels but also decrease the levels of pAkt473 and pAkt308 (the active forms of phosphorylated Akt), similar effect as using AURKA inhibitor Tozasertib (VX680). Furthermore, the AEG-1 shRNA-induced malignant phenotype changes could be mitigated by forced overexpression of AURKA through increased Akt1 activation and phosphorylation in AML cells. On the other hand, although exogenous expression of AEG-1 could increase both AURKA and Akt expression levels the simultaneous use of AURKA inhibitor Tozasertib blocked AEG-1's role of up-regulation of Akt expression in ECV304 cells, suggesting that AURKA might be a key mediator of AEG-1 in regulating Akt activation, and a key effector of AEG-1 in maintaining the malignant state of AML. Moreover, knockdown AEG-1 expression also changed the expression levels of PTEN, survivin and stathmin, the genes that have been reported to be involved in the development of several other malignant tumors. Our results provide evidence for AEG-1's carcinogenesis role in AML and reveal a novel functional link between AEG-1 and AURKA on Akt1 activation. AEG-1 can be an important candidate as a drug design target within AURKA signal pathway for more specific killing of AML cells while sparing normal cells.

Expression of astrocyte elevated gene-1 protein and its clinical significance in laryngeal squamous cell carcinoma

To assess the protein expression of astrocyte elevated gene-1 (AEG-1) in tissue specimens of laryngeal squamous cell carcinoma (LSCC), and to correlate its expression with clinicopathological parameters and prognosis in patients with LSCC. RT-PCR was used to assay the expression of AEG-1 mRNA in 13 pairs of LSCC tissues and their corresponding noncarcinoma epithelia. Immunohistochemistry was performed on paraffin-embedded tissue specimens to investigate the protein expression of AEG-1 in 88 cases of LSCC specimens and 15 cases of adjacent epithelial samples. The expression of AEG-1 mRNA was significantly increased in LSCC tissues compared to adjacent noncarcinoma epithelial tissues (0.81 ± 0.17 vs. 0.23 ± 0.10;t = 10.337, P < 0.001). Meantime, the positive rate of AEG-1 protein in 88 cases of LSCC was 87.5% (77/88). However, 15 cases of adjacent noncarcinoma epithelial merely demonstrated negative or mild expression of AEG-1 protein. AEG-1 overexpression was closely correlated with T stage (χ(2) = 6.289, P = 0.018), clinical stage (χ(2) = 11.049, P < 0.01), metastasis (χ(2) = 20.859, P < 0.01) and recurrence(χ(2) = 13.459, P < 0.01). The overall survival rates of patients with AEG-1 overexpression and low expression were 35.9% and 86.4%, respectively (χ(2) = 23.409, P < 0.01). Multivariate Cox regression analysis revealed that AEG-1 expression was an independent prognostic factor (P = 0.016). AEG-1 protein may play a critical role in the initiation and progression of LSCC, implicating its predictive value in prognosis.

AEG-1 expression characteristics in human non-small cell lung cancer and its relationship with apoptosis

Expression of astrocyte-elevated gene-1 (AEG-1), a novel oncoprotein, has been shown to promote cell growth and inhibit apoptosis, but the underlying molecular mechanisms and its functional significance in non-small cell lung cancer (NSCLC) remain to be elucidated. In the present study, statistical analysis displayed a significant correlation of AEG-1 expression with clinical staging (P = 0.048), differentiation (P = 0.019) and lymph node metastasis (P = 0.032). Simultaneously, the overall survival time in patients with higher AEG-1 expression was obviously shorter than that in patients with lower expression of AEG-1 (P < 0.001). Furthermore, we found that AEG-1 could inhibit apoptotic cell death in L-78 cells, as assessed by MTT, TUNEL and flow cytometry assay. After treating L-78 cells with AEG-1 siRNA, caspase-3 protein was significantly up-regulated and Bcl-2 protein was markedly decreased in L-78 cells, which was verified by the immunohistochemistry results about AEG-1, caspase-3 and Bcl-2. Furthermore, PI3K p110 protein and phosphorylated Akt were also largely attenuated by the treatment of AEG-1 siRNA. In conclusion, our results indicated that AEG-1 played a crucial role in the carcinogenesis of NSCLC and could inhibit apoptosis via activating cell survival signaling (enhancing the level of anti-apoptotic protein Bcl-2 and the activation of PI3K/Akt pathway).

Effect of silencing AEG-1 with small interfering RNA on the proliferation and cell cycle of gastric carcinoma SGC-7901 cells

To explore the effect of down-regulation of astrocyte elevated gene-1 (AEG-1) expression on cell proliferation and cell cycle of gastric carcinoma cells, and its possible molecular mechanism. Control siRNA and AEG-1 siRNA were transfected into gastric carcinoma SGC-7901 cells. 48 h after transfection, the cells were divided into 3 groups including untransfected, siRNA control and AEG-1 siRNA transfection groups. Expressions of AEG-1 mRNA and protein in the 3 group cells were detected by real-time quantitative PCR and Western blot. The changes of cell proliferation were examined using CCK-8 kit, and the cell cycle distribution was detected by flow cytometry. Finally, expressions of cell proliferation and cell cycle related proteins were detected by Western blot. Real-time quantitative PCR and Western blot demonstrated that compared with the untransfected and siRNA control groups, expressions of AEG-1 mRNA and protein were significantly down-regulated in the AEG-1 siRNA transfection group (P < 0.05), but there was no significant difference between the untransfected and siRNA control groups (P > 0.05). Furthermore, in vivo experiment confirmed a significant down-regulation of AEG-1 protein in the AEG-1 siRNA transfection group (P < 0.05). In addition, AEG-1 siRNA obviously inhibited the proliferation of SGC-7901 cells at different time points after transfection with AEG-1 siRNA. The percentage of cells in G0/G1 phase in the AEG-1 siRNA transfection group [(61.26 ± 1.25)%] was significantly higher than those in the untransfected group [(46.17 ± 1.91)%] and siRNA control group [(46.46 ± 1.96)%], and there was a significant difference between them (all P < 0.001). Furthermore, the result of Western blotting revealed that down-regulation of AEG-1 expression evoked the down-regulation of cdk2 and cyclin D1 expressions and elevation of p21 expression in vitro and in vivo. The inhibition of cell proliferation and cell cycle arrest mediated by down-regulation of AEG-1 expression may be closely associated with the changes of expression of cell cycle related proteins including cdk2, cyclin D1 and p21.

Expression characteristics of astrocyte elevated gene-1 (AEG-1) in tongue carcinoma and its correlation with poor prognosis

Astrocyte elevated gene-1 (AEG-1) expression is increased in diverse human cancers and plays a vital role in tumorigenesis and progression. The aim of this study was to investigate the clinicopathologic features and prognostic significance of AEG-1 in squamous cell carcinoma of the tongue (TSCC). Immunohistochemistry (IHC) was performed to examine AEG-1 protein expression in paraffin-embedded tissues from 93 patients with TSCC. Real-time PCR and western blot analyses were employed to examine AEG-1 expression in 4 pairs of primary TSCC and adjacent non-cancerous tissues from the same patient. Immunohistochemical results revealed that the positive rate for AEG-1 in TSCC tissues (48.39%, 45/93) was higher than that in the normal tongue tissues (10.00%, 3/30) (P<0.001). These results were further confirmed between TSCC tissues and matched adjacent non-cancerous tissues by Western blot and RT-PCR. Simultaneously, AEG-1 protein level was positively correlated with differentiation degree (P<0.001), clinical stage (P<0.001), T classification (P=0.007) and N classification (P=0.012). Furthermore, patients with higher AEG-1 expression had shorter overall survival time. Multivariate analysis (Cox regression) also suggested that AEG-1 expression was an independent prognostic indicator for TSCC (P=0.043). Our results indicate that AEG-1 expression is closely associated with carcinogenesis and progression of TSCC, and may represent a novel and valuable predictor for prognostic evaluation of TSCC patients.

Abstract A83: Inhibition of hypoxia inducible factor alpha and astrocyte elevated gene-1 mediates cryptotanshionone induced anti-tumor activity in hypoxic PC-3 cells

Abstract Although cryptotanshinone (CT) from Salvia miltiorrhiza Bunge was known to exert antitumor activity in liver, breast and prostate cancers, its molecular mechanism under hypoxia still remain unclear. Thus, in the present study, the roles of astrocyte elevated gene 1 (AEG-1) and HIF-1α in crytotanshinone induced antitumor activity were investigated in PC-3 prostate cancer cells under hypoxia. Cryptotanshinone exerted cytotoxicity against prostate cancer cells and suppressed HIF-1α accumulation and transcriptional activity and AEG-1 expression in hypoxic PC-3 cells. Also, AGE-1 was overexpressed in prostate cancer cells and also upregulated along with HIF-1α in hypoxic PC-3 cells. Interestingly, HIF-1α siRNA transfection blocked AEG-1 expression and activated caspase 9/3 and PARP cleavage, while AEG-1 siRNA transfection did not affect HIF-1α activity in hypoxic PC-3 cells. Of note, HIF prolyl hydroxylase inhibitor, dimethyloxalylglycine enhanced the stability of AEG-1 and HIF-1α during hypoxia. In addition, CT also significantly reduced cellular levels of VEGF, a downstream of HIF-1α, and disturbed tube formation in human umbilical vein endothelial cells maintained in conditioned medium of hypoxic PC-3 cells. Consistently, ChIP assay revealed that CT inhibited the binding of HIF-1α to VEGF promoter. Furthermore, CT at 10 mg/kg suppressed the growth of PC-3 cells in BALB/c athymic nude mice by 46.4% compared to untreated control. Consistently, immunohistochemistry revealed decreased expression of Ki-67(proliferation), CD34 (blood vessel), VEGF (angiogenesis), carbonic anhydrase(CA)IX (hypoxic marker) and AEG-1 indices in CT-treated group compared to untreated control. Overall, our findings suggest that CT exerts antitumor activity via inhibition of HIF-1α, AEG1 and VEGF as a potent chemotherapeutic agent. Citation Format: Sung Hoon Kim, Hyojeong Lee, Hanna Hyun Kim, Deok Beom Jung, Eunjung Sohn. Inhibition of hypoxia inducible factor alpha and astrocyte elevated gene-1 mediates cryptotanshionone induced antitumor activity in hypoxic PC-3 cells. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A83.

Astrocyte elevated gene-1 promotes hepatocarcinogenesis: Novel insights from a mouse model

Astrocyte elevated gene-1 (AEG-1) is a key contributor to hepatocellular carcinoma (HCC) development and progression. To enhance our understanding of the role of AEG-1 in hepatocarcinogenesis, a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG1) was developed. Treating Alb/AEG-1, but not wild-type (WT) mice, with N-nitrosodiethylamine resulted in multinodular HCC with steatotic features and associated modulation of expression of genes regulating invasion, metastasis, angiogenesis, and fatty acid synthesis. Hepatocytes isolated from Alb/AEG-1 mice displayed profound resistance to chemotherapeutics and growth factor deprivation with activation of prosurvival signaling pathways. Alb/AEG-1 hepatocytes also exhibited marked resistance toward senescence, which correlated with abrogation of activation of a DNA damage response. Conditioned media from Alb/AEG-1 hepatocytes induced marked angiogenesis with elevation in several coagulation factors. Among these factors, AEG-1 facilitated the association of factor XII (FXII) messenger RNA with polysomes, resulting in increased translation. Short interfering RNA-mediated knockdown of FXII resulted in profound inhibition of AEG-1-induced angiogenesis. We uncovered novel aspects of AEG-1 functions, including induction of steatosis, inhibition of senescence, and activation of the coagulation pathway to augment aggressive hepatocarcinogenesis. The Alb/AEG-1 mouse provides an appropriate model to scrutinize the molecular mechanism of hepatocarcinogenesis and to evaluate the efficacy of novel therapeutic strategies targeting HCC.

Expression of AEG-1 in human T-cell lymphoma enhances the risk of progression

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

AEG-1 is associated with clinical outcome in neuroblastoma patients

Astrocyte elevated gene 1 (AEG-1), a novel gene that was cloned in 2002, has emerged in recent years as a potentially crucial mediator of tumor malignancy and aberrant elevation of AEG-1 expression frequently occurs in several human cancers, including breast cancer, prostate cancer, gastric cancer. However, whether AEG-1 deregulation also occurs in neuroblastoma remains unclear. In previous study we reported that AEG-1 was over expressed in neuroblastoma cell lines and knockdown of AEG-1 inhibits proliferation and enhancing chemo-sensitivity to cisplatin or doxorubicin in neuroblastoma cells. In this study, we investigated the expression of AEG-1 and evaluate its prognostic significance by correlating AEG-1 expression levels with clinic pathologic features and survival in 32 archived neuroblastoma patients We found that positive AEG-1 immunoreactivities were present in all neuroblastoma cases, 75% showed high expression of AEG-1. And high expression of AEG-1 was commonly seen in vascular endothelial cells and glandula in neuroblastoma samples. AEG-1 expression was strongly correlated with age at diagnosis (P=0.012), clinical stage (P=0.030) and tumor histology stage (P=0.041). However, our analyses did not show significant associations between AEG-1 expression and other clinical features including gender and primary tumor site. Importantly, our data presented in this report provide, for the first time, evidence that elevated expression of AEG-1 protein is correlated with poor prognosis and reduced survival of patients with neuroblastoma (P= 0.031). Overall, the data support the notion that AEG-1 might be used as a biomarker for neuroblastoma patients.

Abstract 4963: Tanshinone IIA induces JNK-dependent intrinsic apoptosis via suppressing astrocyte-elevated gene 1 expression in chronic myelogenous leukemia KBM-5 cells

Abstract Tanshinone IIA (Tan IIA) is a phytochemical isolated from the root of Salviae miltiorrhizae (Danshen) and has been reported to have various biological activities such as anti-inflammation, anti-oxidation and anti-cancer. However, the underlying molecular mechanisms to control anti-cancer effect of Tan IIA in chronic myelogenous leukemia (CML) have not been fully understood yet. In the present study, we investigated whether Tan IIA has the anti-cancer potential by inducing apoptosis in CML cells. Tan IIA significantly decreased the viability of human CML KBM-5 cells, but not normal peripheral blood lymphocytes. Tan IIA induced apoptotic cell death by increasing the sub-G1 cell populations and stimulating atypical shrunken of nucleus and DNA fragmentation. Also, Tan IIA significantly reduced the mitochondrial membrane potential, stimulated the release of cytochrome C from mitochondria into the cytosol and activated intrinsic caspase cascade. Furthermore, Tan IIA enhanced phosphorylation of JNK and suppressed the expression of astrocyte-elevated gene-1 (AEG-1). In contrast, blocking JNK activity using JNK inhibitor SP600125 reversed Tan IIA-induced apoptosis and AEG-1 expression. Taken together, our findings suggest that Tan IIA induces JNK-dependent intrinsic apoptosis via suppressing AEG-1 expression in KBM-5 cells as a valuable candidate agent for CML therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4963. doi:1538-7445.AM2012-4963

Abstract 1324: Unraveling novel functions of the oncogene Astrocyte elevated gene-1 (AEG-1) contributing to hepatocarcinogenesis employing a transgenic mouse model

Abstract In vitro tissue culture and nude mice xenograft models have firmly established the role of Astrocyte elevated gene-1 (AEG-1) as a positive regulator of tumorigenesis, including hepatocarcinogenesis. To better appreciate the role of AEG-1 in hepatocarcinogenesis and to dissect the underlying molecular mechanism, we have created a transgenic mouse with hepatocyte-specific expression of AEG-1 (Alb/AEG1). Wild-type (WT) and Alb/AEG-1 mice were challenged with a hepatocarcinogen, N-nitrosodiethylamine (DEN), at 2 weeks of age. At 28 weeks of age, Alb/AEG-1 mice, but not WT mice, developed multinodular HCC with steatotic features and highly elevated serum liver enzymes. Affymetrix microarray analyses identified modulation of expression of genes associated with invasion, metastasis, angiogenesis and fatty acid synthesis in DEN-treated Alb/AEG-1 mice versus their WT counterparts. Hepatocytes isolated from Alb/AEG-1 mice demonstrated profound chemoresistance and dramatically evaded reduction in cell viability upon growth factor deprivation, which was associated with activation of multiple pro-survival signaling pathways. Compared to the WT hepatocytes, Alb/AEG-1 hepatocytes demonstrated marked resistance towards senescence, which was associated with abrogation of activation of a DNA damage response. Conditioned media (CM) from Alb/AEG-1 hepatocytes, but not form WT hepatocytes, induced marked angiogenesis. Mass spectrometric analysis of CM revealed noticeable increases in coagulation factors by AEG-1, which are known to play a significant role in regulating tumor invasion, angiogenesis and metastasis. siRNA-mediated knockdown of coagulation factor XII resulted in profound inhibition of AEG-1-induced angiogenesis. Our studies reveal novel aspects of AEG-1 functions, such as induction of steatosis, inhibition of senescence, a known anti-cancer mechanism, and activation of coagulation pathway to augment an aggressive hepatocarcinogenic phenotype. The Alb/AEG-1 mouse will be a useful model to decipher AEG-1 function in the context of hepatocarcinogenesis and to evaluate the efficacy of novel therapeutic strategies directed towards HCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1324. doi:1538-7445.AM2012-1324

Astrocyte elevated gene‐1 interacts with β‐catenin and increases migration and invasion of colorectal carcinoma

To investigate the astrocyte elevated gene-1 (AEG-1) expression and its relationship with the clinicopathological features of colorectal carcinoma (CRC) and β-catenin signaling pathway. Real-time PCR, Western blot, immunohistochemistry, and immunofluorescence staining were performed to detect AEG-1 expression in CRC cell lines, 8 pairs of fresh CRC and adjacent nontumor tissues (ANT), 120 pairs of paraffin-embedded CRC specimens and ANT tissues, and 60 samples of lymph node metastatic CRC tissues. Scratch wound assay and transwell matrix penetration assay were performed to determine migration and invasion of SW480 cell lines with stable AEG-1 overexpression or SW620 cell lines with AEG-1 knockdown. AEG-1 expression was upregulated in CRC cell lines and tissues compared with ANT. Furthermore, AEG-1 expression level significantly correlated with UICC stage, and the N classification. AEG-1 overexpression significantly enhanced migration and invasion of SW480 cell lines. However, AEG-1 knockdown suppressed migration and invasion of SW620 cell lines. Meanwhile, there was a positive correlation between AEG-1 high expression and β-catenin nuclear expression in CRC. AEG-1 overexpression increased nuclear β-catenin accumulation in CRC cell lines. AEG-1 knockdown decreased nuclear β-catenin accumulation in CRC cell lines. Moreover, we firstly found that AEG-1 interacted with β-catenin in SW480 cell lines. Our results for the first time showed that AEG-1 interacted with β-catenin in CRC cells and AEG-1 expression was closely associated with progression of CRC. AEG-1 might be a potential therapeutic target in CRC.

Elevated expression of astrocyte elevated gene‐1 (AEG‐1) is correlated with cisplatin‐based chemoresistance and shortened outcome in patients with stages III–IV serous ovarian carcinoma

To correlate astrocyte elevated gene-1 (AEG-1) expression with the clinicopathological features and outcome of patients with stages III-IV ovarian serous carcinoma, and to clinically assess the involvement of AEG-1 in acquired cisplatin resistance. The frequency and intensity of immunohistochemical AEG-1 expression increased in a step-wise fashion from normal to chemosensitive to chemoresistant tissues. These observations were confirmed by Western blot analysis. AEG-1 expression level was correlated with lymph nodal metastasis, histological differentiation, residual tumour size and response to primary chemotherapy. Five-year progression-free survival (PFS) and overall survival (OS) rates were lower in the high-expression group than that in the low-expression group. AEG-1 overexpression was an independent but poor prognostic factor in the OS and PFS of these patients, as determined by multivariate Cox regression analysis. Multivariate logistic regression analysis revealed that the presence of cisplatin-based chemoresistance was significantly associated with expression level of AEG-1 and the degree of residual disease (P = 0.0001 and P = 0.0027, respectively). Our findings indicate that tumour AEG-1 overexpression is associated with poor prognosis and cisplatin resistance in advanced serous ovarian cancer.

Astrocyte elevated gene-1 (AEG-1) is a marker for aggressive salivary gland carcinoma

BackgroundAstrocyte elevated gene-1 (AEG-1) is associated with tumorigenesis and progression in diverse human cancers. The present study was aimed to investigate the clinical and prognostic significance of AEG-1 in salivary gland carcinomas (SGC).MethodsReal-time PCR and western blot analyses were employed to examine AEG-1 expression in two normal salivary gland tissues, eight SGC tissues of various clinical stages, and five pairs of primary SGC and adjacent salivary gland tissues from the same patient. Immunohistochemistry (IHC) was performed to examine AEG-1 protein expression in paraffin-embedded tissues from 141 SGC patients. Statistical analyses was applies to evaluate the diagnostic value and associations of AEG-1 expression with clinical parameters.ResultsAEG-1 expression was evidently up-regulated in SGC tissues compared with that in the normal salivary gland tissues and in matched adjacent salivary gland tissues. AEG-1 protein level was positively correlated with clinical stage (P < 0.001), T classification (P = 0.008), N classification (P = 0.008) and M classifications (P = 0.006). Patients with higher AEG-1 expression had shorter overall survival time, whereas those with lower tumor AEG-1 expression had longer survival time.ConclusionsOur results suggest that AEG-1 expression is associated with SGC progression and may represent a novel and valuable predictor for prognostic evaluation of SGC patients.

MicroRNA-375 targets AEG-1 in hepatocellular carcinoma and suppresses liver cancer cell growth in vitro and in vivo

MicroRNAs (miRNAs) are believed to have fundamental roles in tumorigenesis and have great potential for the diagnosis and treatment of cancer. However, the roles of miRNAs in hepatocellular carcinogenesis are still not fully elucidated. We investigated the aberrantly expressed miRNAs involved in hepatoma by comparison of miRNA expression profiles in cancerous hepatocytes with normal primary human hepatocytes, and 37 dysregulated miRNAs were screened out by twofold change with a significant difference (P<0.05). Clustering analysis based on 13 miRNAs with changes over 15-folds showed that the miRNA expression patterns between the cancerous and normal hepatocytes were clearly different. Among the 13 miRNAs, we found that miR-375 was significantly downregulated in hepatocellular carcinoma (HCC) tissues and cell lines. Overexpression of miR-375 in liver cancer cells decreased cell proliferation, clonogenicity, migration/invasion and also induced G1 arrest and apoptosis. To unveil the molecular mechanism of miR-375-mediated phenotype in hepatoma cells described above, we examined the putative targets using bioinformatics tools and found that astrocyte elevated gene-1 (AEG-1) was a potential target of miR-375. Then we demonstrated that miR-375 bound directly to the 3'-untranslated region of AEG-1 and inhibited the expression of AEG-1. TaqMan quantitative reverse transcriptase-PCR and western blot analysis showed that miR-375 expression was inversely correlated with AEG-1 expression in HCC tissues. Knockdown of AEG-1 by RNAi in HCC cells, similar to miR-375 overexpression, suppressed tumor properties. Ectopic expression of AEG-1, conversely, could partially reverse the antitumor effects of miR-375. In a mouse model, therapeutic administration of cholesterol-conjugated 2'-O-methyl-modified miR-375 mimics (Chol-miR-375) could significantly suppress the growth of hepatoma xenografts in nude mice. In conclusion, our findings indicate that miR-375 targets AEG-1 in HCC and suppresses liver cancer cell growth in vitro and in vivo, and highlight the therapeutic potential of miR-375 in HCC treatment.