Identification and cloning of human astrocyte genes displaying elevated expression after infection with HIV-1 or exposure to HIV-1 envelope glycoprotein by rapid subtraction hybridization, RaSH

Reduced microRNA 375 in colorectal cancer upregulates metadherin-mediated signaling

BACKGROUND

The human microRNA 375 (MIR375) is significantly downregulated in human colorectal cancer (CRC) and we have previously shown that MIR375 is a CRC-associated miRNA. The metadherin (MTDH) is a candidate target gene of MIR375.

AIM

To investigate the interaction and function between MIR375 and MTDH in human CRC.

METHODS

A luciferase reporter system was used to confirm the effect of MIR375 on MTDH expression. The expression levels of MIR375 and the target genes were evaluated by quantitative RT-PCR (qRT-PCR), western blotting, or immunohistochemistry.

RESULTS

MTDH expression was found to be upregulated in human CRC tissues compared to that in healthy controls. We show that MIR375 regulates the expression of many genes involved in the MTDH-mediated signal transduction pathways [BRAF-MAPK and phosphatidylinositol-4,5-biphosphate-3-kinase catalytic subunit alpha (PIK3CA)-AKT] in CRC cells. Upregulated MTDH expression levels were found to inhibit NF-κB inhibitor alpha, which further upregulated NFKB1 and RELA expression in CRC cells.

CONCLUSION

Our findings suggest that suppressing MIR375 expression in CRC regulates cell proliferation and angiogenesis by increasing MTDH expression. Thus, MIR375 may be of therapeutic value in treating human CRC.

Astrocytic AEG-1 regulates expression of TREK-1 under acute hypoxia

TREK-1 (TWIK-related K+ channel), a member of the two-pore domain K+ (K2P) channel family, is highly expressed in astrocytes, where it plays a key role in glutamate release and passive conductance. In addition, TREK-1 is induced to protect neurons under pathological conditions such as hypoxia. However, the upstream regulation of TREK-1 remains poorly understood. In this study, we found that AEG-1 (astrocyte elevated gene-1) regulates the expression of astrocytic TREK-1 under hypoxic conditions. Upregulation of AEG-1 increased expression of TREK-1 in astrocytes, and knockdown of AEG-1 dramatically decreased the mRNA and protein levels of TREK-1, which were restored by expression of shRNA-insensitive AEG-1. In addition, expression of TREK-1 was not regulated in the absence of AEG-1, even when HIF1α was present. Together, these results suggest that AEG-1 acts as a major upstream regulator of TREK-1 channels in astrocytes under hypoxia. SIGNIFICANCE OF THE STUDY: Previous studies have reported that hypoxia increases the expression of astrocytic TREK-1 and that increased TREK-1 expression protects neuronal cells from apoptosis. However, its cellular mechanism is not clear. In this study we first showed that AEG-1 is a major mediator of hypoxic-regulated TREK-1 expression in normal astrocytes independently of HIF-1α.

AEG-1 aggravates inflammation via promoting NALP3 inflammasome formation in murine endometriosis lesions

Endometriosis (EMs) is one of the most common gynaecological diseases in women of childbearing age. Astrocyte elevated gene-1 (AEG-1) is associated with the invasion, migration, apoptosis and prognosis of various cancers. However, the roles of AEG-1 in EMs and its corresponding molecular mechanism are still unknown. In this study, animal models of EMs were established and mice were divided into two groups (n = 10): Sham group and EMs group. The EMs cells were isolated from EMs model. The AEG-1 gene was knocked down by shRNA, while the SOCS1 gene was knocked down by siRNA. Histological changes, AEG-1 expression in tissues and inflammatory factors level were detected by H&E staining, immunohistochemistry and ELISA, respectively. RT-qPCR and western blotting were used to determine the expression level of related proteins. The present study found AEG-1 was up-regulated in the EMs model. Enhanced AEG-1 promoted inflammatory cell infiltration, and elevated the levels of IL-1β, IL-6, and TNF-α in EM group (p < 0.05). Besides, AEG-1 overexpression promoted the expression of NALP3, ASC and Cleaved-caspase-1, while decreased SOCS1 level (p < 0.05). Decrease of SOCS1 further promoted the formation of NALP3 inflammasome. The inhibitory effect of AEG-1 on SOCS1 was weakened after the addition of MG-132 (p < 0.01). Furthermore, silencing AEG-1 alone increased SOCS1 level, decreased the levels of inflammatory cytokines, thereby inhibited the formation of NALP3 inflammasome. All these results demonstrated that AEG-1 aggravated inflammation via promoting NALP3 inflammasome formation in murine endometriosis lesions.

TNFAIP2 expression induces epithelial-to-mesenchymal transition and confers platinum resistance in urothelial cancer cells

Cisplatin (CDDP)-based chemotherapy is the gold standard treatment for many types of cancer. However, the phenotypic hallmark of tumors often changes after CDDP treatment, with the acquisition of epithelial-to-mesenchymal transition (EMT) and platinum resistance. Furthermore, the mechanisms by which cancer cells acquire EMT under the control of CDDP remain unclear. Following an investigation of urothelial carcinoma (UC) before and after the acquisition of platinum resistance, we offer the new target TNFAIP2, which led to EMT and tumor invasion in platinum-treated UC cells. TNFAIP2 expression in cancer was examined at the protein and transcriptional levels. A potential target for TNFAIP2 during EMT was assessed by microarray. Clinically, upregulated TNFAIP2 expression was identified as a significant predictor of mortality following surgery in three different cohorts of patients with UC (n = 156, n = 119, and n = 54). Knockdown of TNFAIP2 resulted in upregulation of E-cadherin expression and downregulation of TWIST1 expression, which decreased motile function in platinum-resistant UC cells. TNFAIP2 overexpression led to downregulation of E-cadherin expression and upregulation of TWIST1 expression in platinum-naïve UC cells. Clinical investigation of matched pre- and post-CDDP-treated UC sections confirmed upregulation of TNFAIP2 expression in CDDP-treated tumors but downregulation of E-cadherin expression. Global gene expression analysis following TNFAIP2 knockdown identified MTDH as a positive regulator of TNFAIP2-derived EMT acquisition in cancer cells. The present results suggest a relationship between TNFAIP2 and EMT in cancers under the control of CDDP, in which MTDH expression levels in cancer cells are vital for promoting TNFAIP2-derived EMT acquisition.

Metadherin Promotes Malignant Phenotypes And Induces Beta-Catenin Nuclear Translocation And Epithelial-Mesenchymal Transition In Gastric Cancer

Purpose

Metadherin (MTDH), as an oncogene, is associated with metastasis and poor prognosis. This study investigated MTDH expressions and development of gastric cancer (GC) cell phenotypes and the contribution of MTDH to epithelial–mesenchymal transition (EMT).

Patients and methods

MTDH expression was assayed in human GC cell lines and tumor tissue from 92 GC patients. Functional experiments were performed to characterize MTDH activity. Expressions of EMT-related proteins (vimentin and E-cadherin), phosphorylated β-catenin and β-catenin were assayed by immunohistochemistry, Western blotting, immunofluorescence, and co-immunoprecipitation, respectively.

Results

MTDH expressions were higher in GC tissue than that in gastric mucosa from the same patient. MTDH overexpression was correlated with metastasis and enhanced malignant GC phenotypes, i.e., proliferation, migration, invasiveness, and chemoresistance. MTDH overexpression was associated with expressions of vimentin, E-cadherin and cancer stem-cell biomarkers including CD44, CD133, and Oct4. MTDH complexed with β-catenin and decreased phosphorylated β-catenin levels to facilitate β-catenin translocation into the nucleus and expressions of downstream genes.

Conclusion

MTDH overexpression in GC cells is associated with EMT and development of cancer stem cell malignant phenotypes and affects the subcellular translocation of β-catenin. The results warrant investigation of the prognostic value of MTDH in GC and as a therapeutic target.

Study on Diagnostic Values of Astrocyte Elevated Gene 1 (AEG-1) and Glypican 3 (GPC-3) in Hepatocellular Carcinoma

OBJECTIVES

To investigate the diagnostic potential of AEG-1 and GPC-3 in hepatocellular carcinoma (HCC).

METHODS

AEG-1 and GPC-3 immunohistochemistry were performed on HCC, adjacent nontumor tissue (ANT), and dysplastic nodules (DN).

RESULTS

H score of AEG-1 or GPC-3 in HCC was significantly higher than in ANT or DN. In HCC, 92% and 54% showed AEG-1 and GPC-3 positivity, respectively. In ANT, 16.2% were AEG-1 and 7.6% GPC-3 positive. AEG-1 staining was mostly diffuse, whereas GPC-3 frequently showed focal staining. AEG-1 alone showed high sensitivity but low specificity and accuracy. GPC-3, on the other hand, showed high specificity but low sensitivity and accuracy. Combination of both stains boosted the sensitivity, specificity, and accuracy to 94.6%, 89.5%, and 90.5%, respectively, when only diffuse staining was considered as positive.

CONCLUSIONS

AEG-1 or GPC-3 alone seemed not an ideal marker for HCC. The combination of AEG-1 and GPC-3 might improve early diagnosis of HCC.

Regulation of neuroblastoma migration, invasion, and in vivo metastasis by genetic and pharmacological manipulation of MDA-9/Syntenin

Despite multi-modality treatments, prognosis for advanced stage neuroblastoma (NB) remains challenging with residual long-term disabilities in survivors. Advanced stage NB is metastatic, which is a principal cause of cancer-related deaths. We presently document a primary role of MDA-9 in NB progression and define the molecular mechanisms by which MDA-9 promotes transformed phenotypes. NB cell lines and clinical samples display elevated MDA-9 expression and bioinformatic analysis supports an association between elevated MDA-9 and bone metastasis and poor prognosis. Genetic (shmda-9, mda-9 siRNA) or pharmacological (small molecule inhibitor of protein-protein interactions; PDZ1i) blockade of MDA-9 decreases NB migration, invasion, and metastasis. Blocking mda-9 expression or disrupting MDA-9 partner protein interactions downregulates integrin α6 and β4, diminishing Src activity and suppressing Rho-Rac-Cdc42 activity. These signaling changes inhibit cofilin and matrix metalloproteinases reducing in vitro and in vivo NB cell migration. Overexpression of integrin α6 and β4 rescues the invasion phenotype and increases Src activity, supporting integrins as essential regulators of MDA-9-mediated NB migration and invasion. We identify MDA-9 as a key contributor to NB pathogenesis and show that genetic or pharmacological inhibition suppresses NB pathogenesis by an integrin-mediated Src-disruption pathway.

AEG-1 promotes the growth of gastric cancer through the upregulation of eIF4E expression

Background: AEG-1 has been proven to be tumor enhancer in gastric cancer. However, its mechanism has not yet been fully clarified. Methods: Gain-of-function and loss-of-function experiments were conducted to determine the role of eIF4E in AEG-1-induced growth of gastric cancer cells and xenografts of a nude mouse model. Western blot analysis and SRB assay were used to determine the protein expression levels and survival cell numbers. Results: Silencing the expression of AEG-1 inhibited the growth of gastric cancer cells in parallel with a decreased eIF4E and cyclin D1 expression; however, the overexpression of AEG-1 promoted cell growth and increased eIF4E and cyclin D1 expression. Moreover, the overexpression of eIF4E partially reversed the AEG-1 silencing-induced reduction of cyclin D1 and the inhibition of cell growth. An eIF4E knockdown also partially reversed the AEG-1 overexpression-induced upregulation of cyclin D1 and cell growth. Notably, manipulating the expression of eIF4E did not affect the expression of AEG-1. Finally, the silencing of AEG-1 expression inhibited the growth of SGC-7901 xenografts in parallel with the downregulation of eIF4E and cyclin D1 expression in the nude mouse model. Conclusion: AEG-1 promoted the growth of gastric cancer through upregulation of eIF4E/cyclin D1 signaling pathway.

microRNA-564 inhibits the aggressive phenotypes of papillary thyroid cancer by directly targeting astrocyte-elevated gene-1

Background: Accumulating evidence has revealed that an increasing number of microRNAs (miRNAs) are dysregulated in papillary thyroid cancer (PTC) and that their dysregulation plays an important role in PTC onset and progression. Reportedly, miRNA-564 (miR-564) is downregulated in several types of human cancer. However, its expression profile and specific functions in PTC remain unclear to date. Methods: In this study, we used reverse transcription-quantitative polymerase chain reaction to detect miR-564 expression in PTC tissues and cell lines. Further, the regulatory roles of miR-564 in the malignant development of PTC in vitro and in vivo were examined using a series of functional experiments. In addition, the possible underlying mechanisms and signaling pathways involved were investigated. Results: We demonstrated that miR-564 expression markedly decreased in PTC tissues and cell lines, and this decrease correlated with the lymph node metastasis and tumor-node-metastasis stage. miR-564 upregulation significantly inhibited cell proliferation, migration, and invasion and induced cell apoptosis in vitro as well as hindered tumor growth in vivo. Furthermore, astrocyte-elevated gene-1 (AEG-1) was identified as a direct target gene of miR-564 in PTC cells. Its expression was upregulated and inversely correlated with miR-564 expression in clinically PTC tissues. Additionally, the silencing of AEG-1 expression could imitate the action of miR-564 overexpression in PTC cells. Remarkably, the restoration of AEG-1 expression partially abolished the tumor-suppressing effects induced by a miR-564 upregulation in PTC cells. Ectopic miR-564 expression deactivated the PTEN/Akt pathway in PTC cells in vitro and in vivo. Conclusion: Overall, the findings of the current study suggest that miR-564 is a tumor-suppressive miRNA that exerts crucial roles in the development and progression of PTC. Therefore, this miRNA might be a promising candidate target in the anticancer treatment of patients with PTC.

miR-30e-5p suppresses cell proliferation and migration in bladder cancer through regulating metadherin

Recent studies have suggested that miR-30e-5p is dysregulated in several human carcinomas; however, the mechanism of miR-30e-5p in bladder cancer (BCa) remains unknown. Here, we confirmed that the expression of miR-30e-5p was decreased in human BCa specimens and cell lines by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Upregulation of miR-30e-5p decreased the proliferation and migration in T24 and UM-UC-3 cells. Metadherin (MTDH) was a potential target for miR-30e-5p through bioinformatics analysis. Dual-luciferase assays were conducted to validate the interaction between miR-30e-5p and MTDH, which demonstrates that the relative luciferase activity was significantly downregulated after transfected miR-30e-5p mimic compared with control mimic in 293T cells. We also detected that whether silencing of MTDH by using small interfering(si)-MTDH matched effects caused by miR-30e-5p overexpression in BCa cells lines by Cell Counting Kit-8 (CCK-8), colony formation, and transwell assay, and we found the effects of silencing of MTDH same as miR-30e-5p overexpression. Furthermore, we verified that the restoration of MTDH in miR-30e-5p-overexpressed BCa cells rescued the inhibitory effects of miR-30e-5p. In conclusion, these results demonstrated that miR-30e-5p may inhibit BCa cells growth and invasiveness by targeting MTDH and may be a promising therapeutic agent for treating clinical BCa patients.

The targeting of MTDH by miR‑145‑5p or miR‑145‑3p is associated with prognosis and regulates the growth and metastasis of prostate cancer cells

Studies have rarely been conducted on the role of miRNAs in prostate cancer (PCa) cell progression by directly targeting MTDH, at least to the best of our knowledge. Thus, the present study aimed to identify miRNAs closely related with metadherin (MTDH) and to determine their roles in PCa. For this purpose, the expression levels of MTDH in PCa tissues and cell lines were examined by RT‑qPCR, immunohistochemistry and western blot analysis. By cell transfection, MTDH was either overexpressed in the normal prostate epithelial cell lines or silenced in tumor cell lines to determine cell viability, invasion and migration. Bioinformatics analysis, RT‑qPCR, western blot analysis, dual‑luciferase reporter assay and MTT assay were performed to identify direct the target of MTDH and to examine tumor cell viability. Rescue experiments using the PC‑3 and LNCaP cells were carried out by MTT assay, scratch wound assay, Transwell assay, RT‑qPCR and western blot analysis. Experiments were also conducted using 46 PCa human cancer and adjacent tissues, as wells as on 501 cases of PCa from the TCGA database. It was confirmed that the overexpression of MTDH was associated with a poor prognosis of patients. The overexpression of MTDH was found to promote the viability, invasion and migration of PCa cells. miR‑145‑5p and miR‑145‑3p identified from 16 miRNAs were found to be closely related to PCa and to be the targets of MTDH. Both these miRNAs were found to significantly suppress the growth and metastasis of PCa cells by negatively regulating the expression of MTDH. On the whole, the findings of this study demonstrate that MTDH functions as an oncogene in PCa and the inhibition of MTDH by miR‑145‑5p or miR‑145‑3p suppressed the growth and metastasis of PCa cells. The miR‑145‑5p/MTDH and miR‑145‑3p/MTDH pathways may thus become novel treatment targets for PCa.

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.

Metadherin overexpression in perihilar cholangiocarcinoma is associated with lymph node metastasis and poor prognosis

Metadherin (MTDH) is a protein that is also named astrocyte elevated gene-1, and is highly expressed in a number of different tumor tissues. Although the expression of MTDH is associated with tumor invasion and recurrence, the expression of this protein in perihilar cholangiocarcinoma (PCCA) and its clinical use have not yet been investigated. In the present study, the expression of MTDH in patients with PCCA was investigated in order to determine its clinicopathological use. An immunohistochemical method was used to detect MTDH expression and the epithelial-mesenchymal transition markers E-cadherin and vimentin in 66 cases of PCCA. In addition to the expression of MTDH, the clinical and pathological data and the postoperative outcomes were analyzed. The MTDH positive expression rate was 48.5% (32/66) in PCCA. A significantly higher MTDH expression level was identified in the poor tumor differentiation group compared with the well differentiation group (P=0.007). In the positive lymph node metastasis group, a significantly higher MTDH expression level was revealed compared with the negative lymph node metastasis group (P=0.023). No association was noted with regard to the expression of MTDH and the variables age, sex, tumor diameter, tumor grade and tumor classification stage. Positive MTDH expression was significantly associated with high vimentin expression (P=0.037) compared with negative vimentin expression and inversely associated with positive E-cadherin expression compared with negative E-cadherin expression (P=0.030). Survival analysis suggested that the high MTDH expression group was associated with a worse overall survival (OS) rate and recurrence free survival (RFS) rate compared with the low MTDH expression group (P<0.001 and P=0.01, respectively). Cox regression analysis indicated that the Tumor-Node-Metastasis, surgery margin and high MTDH expression were independent OS and RFS factors for PCCA. MTDH expression may serve an important function in PCCA tumor growth and metastasis. Targeting MTDH may have important therapeutic applications for patients with PCCA.

[Effect of telmisartan on expression of metadherin in the kidney of mice with unilateral ureter obstruction]

OBJECTIVE

To explore the effect of telmisartan on the expression of metadherin in the kidney of mice with unilateral ureter obstruction.

METHODS

Eighteen male C57 mice were randomized into sham-operated group, model group and telmisartan treatment group. In the latter two groups, renal interstitial fibrosis as the result of unilateral ureter obstruction (UUO) was induced by unilateral ureteral ligation with or without telmisartan intervention. Renal pathological changes of the mice were assessed using Masson staining, and immunohistochemistry and Western blotting were used to detect the expression of extracellular matrix proteins and metadherin in the kidney of the mice. In the in vitro experiment, cultured mouse renal tubular epithelial cells (mTECs) were stimulated with transforming growth factor-β1 (TGF-β1) and transfected with a siRNA targeting metadherin, and the changes in the expressions of extracellular matrix proteins and metadherin were detected using Western blotting.

RESULTS

The expressions of extracellular matrix proteins and metadherin increased significantly in the kidney of mice with UUO (P &lt; 0.05). Intervention with telmisartan significantly lowered the expressions of extracellular matrix proteins and metadherin and alleviated the pathology of renal fibrosis in mice with UUO (P &lt; 0.05). In cultured mTECs, siRNA-mediated knockdown of metadherin obviously reversed TGF-β1-induced increase in the expressions of extracellular matrix proteins and metadherin.

CONCLUSIONS

Telmisartan can suppress the production of extracellular matrix proteins and the expression of metadhein to attenuate UUO-induced renal fibrosis in mice.

CCL18 promotes the metastasis of squamous cell carcinoma of the head and neck through MTDH-NF-κB signalling pathway

Metastasis is one of the primary causes for high mortality in patients with squamous cell carcinoma of the head and neck (SCCHN). Our previous study showed that chemokine (C‐C motif) ligand 18 (CCL18), derived from tumour‐associated macrophages (TAMs), regulates SCCHN metastasis by promoting epithelial‐mesenchymal transition (EMT) and preserving stemness. However, the underlying mechanism needs to be further investigation. Interestingly, metadherin (MTDH) expression was induced when SCCHN cells were stimulated with recombinant CCL18 protein in this study. Suppressing MTDH expression reversed CCL18‐induced migration, invasion and EMT in SCCHN cells. Furthermore, the NF‐κB signalling pathway was involved in the MTDH knock‐down cells with CCL18 stimulation. We performed ELISA to evaluate the CCL18 levels in the serums of 132 treatment‐naive SCCHN patients, 25 patients with precancerous lesion and 32 healthy donors. Our results demonstrated that serum CCL18 levels were significantly higher in SCCHN patients than patients with precancerous lesion and healthy individuals. CCL18 levels were found to be significantly correlated with tumour classification, clinical stage, lymph node metastasis and histological grade in SCCHN patients. Thus, our findings suggest that CCL18 may serve as a potential biomarker for diagnosis of SCCHN and promote SCCHN invasion, migration and EMT by MTDH‐NF‐κB signalling pathway.

miR‑3664‑5P suppresses the proliferation and metastasis of gastric cancer by attenuating the NF‑κB signaling pathway through targeting MTDH

Gastric cancer (GC) is one of the most common and fatal types of cancers worldwide and the specific mechanism has not been completely elucidated. microRNA (miR)‑3664‑5P has rarely been studied and the aim of the present study was to assess an association between miR‑3664‑5P and GC. Differences in miR‑3664‑5P expression in 100 GC (0.1846±0.08276) and paired normal tissues (0.4382±0.1595) were detected using reverse transcription‑quantitative polymerase chain reaction assays (P<0.001). 5‑Ethynyl‑2‑deoxyuridine, Cell Counting Kit‑8, transwell and flow cytometry assays were performed in vitro and the results were further verified using a mouse xenotransplantation and a lung metastasis model in vivo. miR‑3664‑5P was significantly downregulated in GC tissues when compared with normal tissues and positively associated with the prognosis of patients with GC (P<0.001). Overexpression of miR‑3664‑5P suppressed and miR‑3664‑5P knockdown promoted the proliferation and metastasis of GC cells in vitro and in vivo. Following the application of bioinformatic algorithms and luciferase reporter assays, metadherin (MTDH) was confirmed as the target gene of miR‑3664‑5P. miR‑3664‑5P reduced MTDH expression and downregulated the nuclear factor (NF)‑κB signaling pathway. Rescue experiments demonstrated that suppression of MTDH restored the effect of miR‑3664‑5P inhibitors on GC cell lines. The results suggested that miR‑3664‑5P suppressed the proliferation and metastasis of GC cells by attenuating the NF‑κB signaling pathway via MTDH targeting. Consequently, miR‑3664‑5P may have potential to be an independent prognostic factor and biomarker in GC.

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.

MicroRNA‑758 inhibits tumorous behavior in tongue squamous cell carcinoma by directly targeting metadherin

Numerous microRNAs (miRNAs) are dysregulated in tongue squamous cell carcinoma (TSCC), and their dysregulation has been demonstrated to have a strong correlation with TSCC progression via regulation of their targets. Therefore, miRNAs have potential use in the diagnosis and treatment of patients with TSCC. In the present study, miRNA‑758 (miR‑758) expression in TSCC tissues and cell lines was detected through reverse transcription‑quantitative polymerase chain reaction, and the effects of miR‑758 on TSCC cell proliferation and invasion were investigated by using Cell Counting kit‑8 and Transwell invasion assays. A luciferase reporter assay was performed to determine the target interaction between miR‑758 and metadherin (MTDH) in TSCC cells. The results revealed that miR‑758 was downregulated in TSCC tissues and cell lines. miR‑758 overexpression restricted the proliferation and invasion of TSCC cells. Additionally, MTDH was verified as a direct target gene of miR‑758 in TSCC cells. Furthermore, MTDH was observed to be upregulated in TSCC tissues, and the upregulation of MTDH was inversely correlated with miR‑758 expression. Moreover, restored MTDH expression significantly counteracted the suppressive effects of miR‑758 overexpression on TSCC cells. These results suggested that miR‑758 may prevent TSCC progression and development by directly targeting MTDH, thereby providing evidence that miR‑758 is a novel therapeutic target for the treatment of patients with TSCC.

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.

A Preliminary Study on Metadherin as a Potential Marker for Progression of Diffuse Large B Cell Lymphoma

AIMS

To determine if Metadherin (MTDH) expression levels are positively correlated with the clinical stage of diffuse large B-cell lymphoma (DLBCL) based on MTDH being highly expressed in other type of tumors including melanoma, malignant glioma, breast cancer, and hepatocellular carcinoma. In this study, we investigated the pathologic significance of MTDH and its potential in predicting DLBCL outcomes.

MATERIALS AND METHODS

Tissue samples from 50 patients with DLBCL and 22 patients with lymph node reactive hyperplasia were collected and evaluated using immunohistochemical staining, microscopy, and western blotting. The Kaplan-Meier method and Cox regression model were used for survival analysis of patients.

RESULTS

Our results show that the overexpression of the MTDH protein in tissues was observed in 66% of patients with DLBCL, whereas it was not overexpressed in the patients with reactive hyperplastic lymph nodes. While there was no correlation between MTDH overexpression with age, sex, presence of B symptoms, and lactate dehydrogenase (LDH) levels in patients with DLBCL, this parameter was positively correlated with clinical stages. Moreover, MTDH-negative patients had significantly better prognoses compared with the MTDH-positive patients.

CONCLUSION

Our preliminary study indicates that MTDH may play an important role in the development of DLBCL, and that MTDH overexpression is potentially associated with the clinical progression of DLBCL. In addition, high expression levels of MTDH in tissues was correlated with a poorer prognosis for patients with DLBCL. As such, MTDH may be a potential therapeutic target for specific therapy. However, research on a larger group of patients is needed to verify these preliminary results.

Efficient and tumor-specific knockdown of MTDH gene attenuates paclitaxel resistance of breast cancer cells both in vivo and in vitro

Background

Drug resistance of paclitaxel (TAX), the first-line chemotherapy drug for breast cancer, was reported to develop in 90% of patients with breast cancer, especially metastatic breast cancer. Investigating the mechanism of TAX resistance of breast cancer cells and developing the strategy improving its therapeutic efficiency are crucial to breast cancer cure.

Methods and Results

We here report an elegant nanoparticle (NP)-based technique that realizes efficient breast cancer treatment of TAX. Using lentiviral vector-mediated gene knockdown, we first demonstrated that TAX therapeutic efficiency was closely correlated with metadherin (MTDH) gene expression in breast cancer cell lines. This finding was also supported by efficacy of TAX treatment in breast cancer patients from our clinical studies. Specifically, TAX treatment became more effective when MTDH expression was decreased in MCF-7 cancer cells by the blocking nuclear factor-kappa B (NF-κB) pathway. Based on these findings, we subsequently synthesized a polymeric NP that could co-deliver MTDH-small interfering RNA (MTDH–siRNA) and TAX into the breast cancer tumors in tumor-bearing mice. The NPs were composed of a cationic copolymer, which wrapped TAX in the inside and adsorbed the negatively charged siRNA on their surface with high drug-loading efficiency and good stability.

Conclusions

NP-based co-delivery approach can effectively knock down the MTDH gene both in vitro and in vivo, which dramatically inhibits breast tumor growth, achieving effective TAX chemotherapy treatment without overt side effects. This study provides a potential therapeutic strategy for the treatment of a wide range of solid tumors highly expressing MTDH.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1042-7) contains supplementary material, which is available to authorized users.

MicroRNA‑655 suppresses cell proliferation and invasion in oral squamous cell carcinoma by directly targeting metadherin and regulating the PTEN/AKT pathway

MicroRNAs (miRNAs) are important regulators of a variety of biological processes and their dysregulation is closely related to cancer formation and progression. Therefore, examination of aberrantly expressed miRNAs in oral squamous cell carcinoma (OSCC) may provide important clues for the diagnosis and treatment of patients with OSCC. The aim of the present study was to determine miRNA (miR)‑655‑3p expression in OSCC tissues and cell lines, and to investigate the biological roles and mechanisms of miR‑655‑3p associated with OSCC. Data from the present study indicated that miR‑655 expression was significantly downregulated in human OSCC tissues and cell lines. Overexpression of miR‑655 attenuated cell proliferation and invasion in OSCC in vitro. Metadherin (MTDH) mRNA was predicted as a potential target of miR‑655 by bioinformatics analysis, and this was confirmed by luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis. In OSCC tissues, MTDH was highly expressed and inversely correlated with miR‑655 expression levels. MTDH overexpression reversed the inhibitory effects of miR‑655 mimics in OSCC cells. Notably, the upregulation of miR‑655 expression inhibited the activation of the phosphatase and tensin homolog (PTEN)/RAC‑α serine/threonine‑protein kinase (AKT) pathway in OSCC cells. Therefore, these results may provide the first evidence that miR‑655 targets MTDH to inhibit proliferation and invasion of OSCC by inhibiting PTEN/AKT signaling. Thus, the restoration of miR‑655 expression may be a novel therapeutic strategy for patients with OSCC.

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.

HIV-1 Tat inhibits EAAT-2 through AEG-1 upregulation in models of HIV-associated neurocognitive disorder

During HIV-associated neurocognitive disorder (HAND), decreasing in excitatory amino acid transporter 2 (EAAT-2) in astrocyte plasma membranes leads to elevated levels of extracellular glutamate and, in turn, neuronal apoptosis. We used immunohistochemistry, western blot, qRT-PCR, and RNA interference to elucidate the molecular mechanisms underlying the decreased EAAT-2 expression during HAND at the tissue and cellular levels. We used simian immunodeficiency virus-human immunodeficiency virus chimeric virus (SHIV)-infected macaques as an in vivo model of HAND. Our results show that EAAT-2 expression was decreased in the cerebral cortex, while AEG-1 expression was increased, and the expression levels of these proteins were negatively correlated. In vitro analyses showed that HIV-1 Tat inhibited EAAT-2 expression by inducing overexpression of AEG-1. More specifically, HIV-1 Tat increased AEG-1 expression via the PI3-K signaling pathway, while increasing EAAT-2 inhibition by YinYan-1 (YY-1) via the NF-κB signaling pathway. These results warrant testing AEG-1 as a potential therapeutic target for treating HAND.

Astrocyte elevated gene-1 is a novel regulator of astrogliosis and excitatory amino acid transporter-2 via interplaying with nuclear factor-κB signaling in astrocytes from amyotrophic lateral sclerosis mouse model with hSOD1G93A mutation

AEG-1 has received extensive attention on cancer research. However, little is known about its roles in astrogliosis of Amyotrophic lateral sclerosis (ALS). In this study, we detected AEG-1 expression in hSOD1G93A-positive (mut-SOD1) astrocytes and wild type (wt-SOD1) astrocytes, and intend to elucidate its potential functions in ALS related astrogliosis and the always accompanied dysregulated glutamate clearance. Results showed elevated protein and mRNA levels of AEG-1 in mut-SOD1 astrocytes; Also, NF-κB signaling pathway related proteins and inflammatory cytokines were upregulated in mut-SOD1 astrocytes; AEG-1 knockdown attenuated astrocytes proliferation and pro-inflammatory release; also we found that AEG-1 silence inhibited translocation of p65 from cytoplasma to nuclear, which was associated with inhibited NF-κB signaling. Besides, excitatory amino acid transporter-2 (EAAT2) expression levels were significantly decreased, accompanied by impaired glutamate clearance ability, in mut-SOD1 astrocytes; yin yang 1 (YY1), a transcriptional inhibitor for EAAT2, increased in nucleus of mut-SOD1 astrocytes. AEG-1 silence inhibited translocation of YY1 to nucleus, increased EAAT2 expression levels, and enhanced astrocytic ability of glutamate clearance, ultimately exerted the neuronal protection. Findings from this study implicate potential function of AEG-1 in mut-SOD1 related astrogliosis and the accompanied excitatory cytotoxic mechanism in ALS.

Upregulation of neuronal astrocyte elevated gene-1 protects nigral dopaminergic neurons in vivo

The role of astrocyte elevated gene-1 (AEG-1) in nigral dopaminergic (DA) neurons has not been studied. Here we report that the expression of AEG-1 was significantly lower in DA neurons in the postmortem substantia nigra of patients with Parkinson’s disease (PD) compared to age-matched controls. Similarly, decreased AEG-1 levels were found in the 6-hydroxydopamine (6-OHDA) mouse model of PD. An adeno-associated virus-induced increase in the expression of AEG-1 attenuated the 6-OHDA-triggered apoptotic death of nigral DA neurons. Moreover, the neuroprotection conferred by the AEG-1 upregulation significantly intensified the neurorestorative effects of the constitutively active ras homolog enriched in the brain [Rheb(S16H)]. Collectively, these results demonstrated that the sustained level of AEG-1 as an important anti-apoptotic factor in nigral DA neurons might potentiate the therapeutic effects of treatments, such as Rheb(S16H) administration, on the degeneration of the DA pathway that characterizes PD.

Metadherin is an apoptotic modulator in prostate cancer through miR-342-3p regulation

Prostate cancer is the second most common cancer in men worldwide. This study focused to clarify the roles of Metadherin (MTDH) and miR-342-3p in prostate cancer. We identified that MTDH was up-regulated and miR-342-3p was down-regulated in the prostate tissues, and there is an inverse correlation between MTDH and miR-342-3p. Functional studies revealed that miR-342-3p directly targets MTDH via binding to the 3' untranslated regions (UTRs) in the prostate cancer cells. Moreover, we also found MTDH overexpression in DU145 and PC3 cells inhibited apoptosis. Subsequently, miR-342-3p has been revealed to reverse the MTDH effect on the cellular apoptosis in the further studies. Our results indicate that MTDH repress apoptosis of prostate cancer in vitro and provides a new strategy for human prostate cancer therapy in the future.

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.

MicroRNA-320a inhibits breast cancer metastasis by targeting metadherin

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

Metadherin: An emerging key regulator of the malignant progression of multiple cancers

We and others recently identified the gene metadherin (MTDH) as a functional driver in multiple aspects of cancer progression. It is overexpressed in cancer cells originating from a variety of tissues, partially due to DNA amplification of the chromosomal 8q22 region where this gene resides. The rapidly accumulated data from MTDH studies of the past several years have documented its role in tumorigenesis, angiogenesis, cell proliferation, survival, anchorage-independent growth, metastasis and chemoresistance. In particular, it simultaneously helps the primary tumor cells to survive conventional chemotherapy and spread to distant organs, both of which are major contributors to cancer therapy failure and ultimately patient death. The efforts to elucidate the molecular mechanism of MTDH functions led to observations indicating its involvement in several prominent cancer-related signaling pathways including Ras, c-Myc, PI3K/AKT, NF-κB, Wnt/β-catenin, and more recently, microRNA machinery. Herein we will briefly summarize the studies that establish MTDH as a promising target for cancer therapeutics.

Long noncoding RNA SNHG1 promotes non-small cell lung cancer progression by up-regulating MTDH via sponging miR-145-5p

Long noncoding RNAs participate in the progression and initiation of non-small cell lung cancer (NSCLC), although the mechanism remains unknown. The lncRNA identified as small nucleolar RNA host gene 1 ( SNHG1) is a novel lncRNA that is increased in multiple human cancers; however, the regulatory mechanism requires further investigation. In this study, we discovered that SNHG1 was markedly up-regulated in NSCLC tissues and cells and that SNHG1 silencing decreased tumor volumes. Moreover, we explored its regulatory mechanism and found that SNHG1 directly bound to microRNA (miRNA)-145-5p, isolating miR-145-5p from its target gene MTDH. Inhibition of SNHG1 suppressed NSCLC cell viability, proliferation, migration, and invasion in vitro, but its effect was rescued by miR-145-5p inhibition. These results demonstrate that SNHG1 contributes to NSCLC progression by modulating the miR-145-5p/ MTDH axis, and it could potentially be a therapeutic target as well as a diagnostic marker.-Lu, Q., Shan, S., Li, Y., Zhu, D., Jin, W., Ren, T. Long noncoding RNA SNHG1 promotes non-small cell lung cancer progression by up-regulating MTDH via sponging miR-145-5p.

Nanoscale polysaccharide derivative as an AEG-1 siRNA carrier for effective osteosarcoma therapy

Background

Nanomedicine, which is the application of nanotechnology in medicine to make medical diagnosis and treatment more accurate, has great potential for precision medicine. Despite some improvements in nanomedicine, the lack of efficient and low-toxic vectors remains a major obstacle.

Objective

The aim of this study was to prepare an efficient and low-toxic vector which could deliver astrocyte elevated gene-1 (AEG-1) small interfering RNA (siRNA; siAEG-1) into osteosarcoma cells effectively and silence the targeted gene both in vitro and in vivo.

Materials and methods

We prepared a novel polysaccharide derivative by click conjugation of azidized chitosan with propargyl focal point poly (L-lysine) dendrons (PLLD) and subsequent coupling with folic acid (FA; Cs-g-PLLD-FA). We confirmed the complexation of siAEG-1and Cs-g-PLLD or Cs-g-PLLD-FA by gel retardation assay. We examined the cell cytotoxicity, cell uptake, cell proliferation and invasion abilities of Cs-g-PLLD-FA/siAEG-1 in osteosarcoma cells. In osteosarcoma 143B cells tumor-bearing mice models, we established the therapeutic efficacy and safety of Cs-g-PLLD-FA/siAEG-1.

Results

Cs-g-PLLD-FA could completely encapsulate siAEG-1 and showed low cytotoxicity in osteosarcoma cells and tumour-bearing mice. The Cs-g-PLLD-FA/siAEG-1 nanocomplexes were capable of transferring siAEG-1 into osteosarcoma cells efficiently, and the knockdown of AEG-1 resulted in the inhibition of tumour cell proliferation and invasion. In addition, caudal vein injecting of Cs-g-PLLD-FA/siAEG-1 complexes inhibited tumor growth and lung metastasis in tumor-bearing mice by silencing AEG-1 and regulating MMP-2/9.

Conclusion

In summary, Cs-g-PLLD-FA nanoparticles are a promising system for the effective delivery of AEG-1 siRNA for treating osteosarcoma.

MicroRNA‑675 inhibits cell proliferation and invasion in melanoma by directly targeting metadherin

Melanoma is derived from melanocytes and accounts for ~80% of skin cancer-associated fatalities worldwide. The dysregulation of microRNAs (miRNAs/miRs) is involved in the development and progression of melanoma. Therefore, miRNAs may be novel diagnostic or prognostic biomarkers and promising therapeutic targets in the treatment of patients with melanoma. miR‑675 is differentially expressed in several types of human cancer and has important roles in the pathogenesis of several diseases. However, the expression levels and the biological roles of miR‑675 in melanoma remain unclear. Therefore, the present study aimed to assess the expression of miR‑675 in melanoma, explore the effects of miR‑675 on melanoma cells and investigate the underlying molecular mechanisms that may be involved in the actions of miR‑675. The present study indicated that miR‑675 expression was downregulated in melanoma tissues and cell lines. Functional assays demonstrated that the upregulation of miR‑675 impaired cell proliferation and invasion in melanoma. Bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis demonstrated that metadherin (MTDH) was a direct target of miR‑675 in melanoma. The MTDH levels were upregulated in melanoma tissues and inversely correlated with the miR‑675 expression. Furthermore, restored MTDH expression rescued the inhibition effects in melanoma cells caused by miR‑675 overexpression. Thus, miR‑675 may be a potential therapeutic target for melanoma.

MicroRNA-584 inhibits cell proliferation and invasion in non-small cell lung cancer by directly targeting MTDH

Lung cancer is the third most frequent human malignant tumour and the leading cause of cancer-associated mortality worldwide. Emerging lines of evidence have demonstrated that microRNAs (miRNAs) are upregulated or downregulated in non-small cell lung cancer (NSCLC), and this phenomenon is involved in the regulation of various processes during tumorigenesis and progression, including tumour groWTh, apoptosis, cell invasion, and tumour metastasis. Therefore, understanding the molecular mechanism that associates abnormally expressed miRNAs with NSCLC formation and development may lead to the identification of novel diagnostic, and therapeutic targets for patients with NSCLC. miRNA-584 (miR-584) functions as a tumour suppressor in several types of cancer. However, the expression pattern, detailed biological function and underlying molecular mechanism of miR-584 in NSCLC remain unclear. Therefore, the present study detected the expression of miR-584 in NSCLC, investigated its role in NSCLC cells and determined its underlying molecular mechanism. In the current study, it was demonstrated that miR-584 was downregulated in NSCLC tissues and cell lines. Low miR-584 expression was correlated with tumour size, tumour node metastasis stage and distant metastasis. Overexpression of miR-584 inhibited cell proliferation and invasion in NSCLC. Additionally, metadherin was identified as a direct target gene of miR-584 in NSCLC as confirmed by a series of experiments. Moreover, upregulation of miR-584 was involved in the regulation of the phosphatase and tensin homolog/Akt serine/threonine kinase signalling pathway in NSCLC. Thus, miR-584 may serve as a tumor-suppressor, and the results of the present study provide a reference for future research into the potential mechanisms underlying NSCLC progression.

miR‑96 inhibits EMT by targeting AEG‑1 in glioblastoma cancer cells

The induction of epithelial to mesenchymal transition (EMT) is important for carcinogenesis and cancer progression. Previous studies have estimated that microRNA (miRNA/miR) expression is associated with EMT via the regulation of the expression of target genes. miR-96 has been reported to exhibit a correlation with the EMT process. However, the functional role of miR-96 and its mechanism in glioblastoma multiforme (GBM) remains to be completely elucidated. The objective of the present study was to investigate the functional role and mechanism of miR-96 in the migration and invasion, in addition to proliferation, apoptosis and cell cycle distribution, of GBM. In the present study, the results suggested that the introduction of miR-96 significantly inhibited the migration and invasion, in addition to proliferation and cell cycle progression, of GBM cells and promoted their apoptosis in vitro, leading to the hypothesis that miR-96 may be a potential tumor suppressor. It was subsequently confirmed that astrocyte elevated gene-1 (AEG-1) was a direct target gene of miR-96, using a luciferase assay and reverse transcription-quantitative polymerase chain reaction analysis, in addition to western blotting. miR-96 was observed to downregulate the expression of AEG-1 at the mRNA and protein levels. Notably, AEG-1 may suppress EMT by increasing the expression levels of E-cadherin, an epithelial marker, and decreasing the expression levels of vimentin, a mesenchymal marker. Therefore, it was concluded that miR-96 may impede the EMT process by downregulating AEG-1 in GBM. Additionally, it was observed that inhibition of AEG-1 led to a similar effect compared with overexpression of miR-96 in GBM. In conclusion, the results of the present study demonstrated that miR-96 may act as a tumor suppressor by regulating EMT via targeting of AEG-1, suggesting that miR-96 may be a potential biomarker and anticancer therapeutic target for GBM in the future.

HIV-1-associated inflammation and antiretroviral therapy regulate astrocyte endoplasmic reticulum stress responses

Antiretroviral (ARV) therapy (ART) has effectively suppressed the incidence of human immunodeficiency virus (HIV)-associated dementia in HIV-1 positive individuals. However, the prevalence of more subtle forms of neurocognitive dysfunction continues to escalate. Recently, endoplasmic reticulum (ER) stress has been linked to many neurological diseases; yet, its role in HIV/neuroAIDS remains largely unexplored. Furthermore, upregulation of astrocyte elevated gene-1 (AEG-1), a novel HIV-1 inducible gene, along with ER stress markers in a Huntington’s disease model, suggests a possible role in HIV-associated ER stress. The current study is focused on unfolded protein responses (UPRs) and AEG-1 regulation in primary human astrocytes exposed to HIV-associated neurocognitive disorders (HAND)-relevant stimuli (HIV-1 virions, inflammation and ARV drugs). Interleukin (IL)-1β and the nucleoside reverse transcriptase inhibitor abacavir upregulated expression of ER stress markers in human astrocytes, including binding immunoglobulin protein (BiP), C/EBP homologous protein (CHOP), and calnexin. In addition, IL-1β activated all three well-known UPR pathways: protein kinase RNA-like ER kinase (PERK); activating transcription factor 6 (ATF-6); and inositol-requiring enzyme 1α (IRE1α). AEG-1 upregulation correlated to ER stress and demonstrated astrocyte AEG-1 interaction with the calcium-binding chaperone, calnexin. IL-1β and abacavir enhanced intracellular calcium signaling in astrocytes in the absence of extracellular calcium, illustrating ER-associated calcium release. Alternatively, calcium evoked in response to HAND-relevant stimuli led to mitochondrial permeability transition pore (mPTP) opening in human astrocytes. Importantly, IL-1β- and abacavir-induced UPR and mPTP opening were inhibited by the intracellular calcium chelation, indicating the critical role of calcium signaling in HAND-relevant ER stress in astrocytes. In summary, our study highlights that ARV drugs and IL-1β induced UPR, AEG-1 expression, intracellular calcium, and mitochondrial depolarization in astrocytes. This study uncovers astrocyte ER stress as a novel therapeutic target in the management of HIV-1-associated neurotoxicity and possibly in the treatment of neuroAIDS.

AEG-1/MTDH-activated autophagy enhances human malignant glioma susceptibility to TGF-β1-triggered epithelial-mesenchymal transition

Autophagy is a tightly regulated process activated in response to metabolic stress and other microenvironmental changes. Astrocyte elevated gene 1 (AEG-1) reportedly induces protective autophagy. Our results indicate that AEG-1 also enhances the susceptibility of malignant glioma cells to TGF-β1-triggered epithelial-mesenchymal transition (EMT) through induction of autophagy. TGF-β1 induced autophagy and activated AEG-1 via Smad2/3 phosphorylation in malignant glioma cells. Also increased was oncogene cyclin D1 and EMT markers, which promoted tumor progression. Inhibition of autophagy using siRNA-BECN1 and siRNA-AEG-1 suppressed EMT. In tumor samples from patients with malignant glioma, immunohistochemical assays showed that expression levels of TGF-β1, AEG-1, and markers of autophagy and EMT, all gradually increase with glioblastoma progression. In vivo siRNA-AEG-1 administration to rats implanted with C6 glioma cells inhibited tumor growth and increased the incidence of apoptosis among tumor cells. These findings shed light on the mechanisms underlying the invasiveness and progression of malignant gliomas.

Astrocyte elevated gene-1 promotes invasion and epithelial-mesenchymal transition in bladder cancer cells through activation of signal transducer and activator of transcription 3

OBJECTIVES

To determine the impact of astrocyte elevated gene-1 on the invasion and epithelial-mesenchymal transition of bladder cancer cells in vitro and metastasis in vivo.

METHODS

Gain- and loss-of-function studies were carried out to investigate the biological roles of astrocyte elevated gene-1 in bladder cancer cell invasion, epithelial-mesenchymal transition and lung metastasis. The mechanism underlying the activity of astrocyte elevated gene-1 was examined.

RESULTS

Overexpression of astrocyte elevated gene-1 led to a significant increase in the invasive ability of UMUC3 and T24 bladder cancer cells in Matrigel invasion assays. In contrast, silencing of astrocyte elevated gene-1 restrained bladder cancer cell invasion. Overexpression of astrocyte elevated gene-1 downregulated E-cadherin and upregulated vimentin and Twist1, while silencing of astrocyte elevated gene-1 exerted an opposite effect. Mechanistically, astrocyte elevated gene-1 overexpression promoted the phosphorylation of signal transducer and activator of transcription 3 in bladder cancer cells. Treatment with WP1066, a specific signal transducer and activator of transcription 3 inhibitor, significantly abolished astrocyte elevated gene-1-induced invasion and epithelial-mesenchymal transition in UMUC3 cells. In vivo studies showed that astrocyte elevated gene-1 overexpression stimulated the growth of UMUC3 xenograft tumors and lung metastasis.

CONCLUSIONS

Astrocyte elevated gene-1 shows the ability to promote bladder cancer metastasis, which is causally linked to induction of signal transducer and activator of transcription 3 activation and epithelial-mesenchymal transition. Therefore, targeting astrocyte elevated gene-1 might offer therapeutic benefits in treating metastatic bladder cancer.

let-7d suppresses proliferation and invasion and promotes apoptosis of meningioma by targeting AEG-1

BACKGROUND

let-7d has been indicated to act as a tumor suppressor in various cancers. However, the function and molecular mechanism of let-7d in meningioma progression have not been elucidated.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of let-7d and AEG-1 mRNA in meningioma tissues and cell lines. The protein level of AEG-1 was measured by Western blot analysis. MTT assay, Transwell invasion assay and flow cytometry analysis were carried out to determine the proliferation, invasion and apoptosis of IOMM-Lee and CH-157MN cells, respectively. Target gene of let-7d was verified by luciferase reporter analysis.

RESULTS

let-7d expression was downregulated, and AEG-1 expression was upregulated in meningioma tumor tissues. let-7d overexpression suppressed proliferation and invasion and induced apoptosis in IOMM-Lee and CH-157MN cells. Moreover, AEG-1 was a direct target of let-7d. Restoration of AEG-1 expression reversed let-7d-mediated suppression of the proliferation and invasion and let-7d-induced apoptosis in IOMM-Lee and CH-157MN cells.

CONCLUSION

let-7d repressed proliferation and invasion and promoted apoptosis of meningioma cells by targeting AEG-1. The present study provided a better understanding of the meningioma pathogenesis and a promising therapeutic target for meningioma patients.

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.

AEG-1 mRNA expression in non-small cell lung cancer is associated with increased tumor angiogenesis

Astrocyte-elevated gene-1 (AEG-1) is implicated in the oncogenesis and angiogenesis of various types of human malignant disease. However, the angiogenesis roles of AEG-1 in non-small cell lung cancer (NSCLC) remain to be further elucidated. In the present study, the expression level of AEG-1 mRNA in seven human lung cell lines and 89 paired tissue samples (tumor tissues (TTs) and pair-matched normal adjacent tissues (PMNATs)) from NSCLC patients was detected by real-time PCR. Staining of vascular endothelial growth factor (VEGF) and intratumoral microvessel density (iMVD, labeled by CD105) were assessed by immunohistochemistry. Furthermore, cell migration and invasion were evaluated by wound healing assay and transwell assays. AEG-1 mRNA level was significantly higher in human lung cancer cells and TTs than that in human normal bronchial epithelial cell line 16HBE and PMNATs, respectively (P<0.001). Higher AEG-1 mRNA level in patients with NSCLC was correlated with clinical stages (P=0.028), differentiation (P=0.042), and lymph node metastasis (P=0.004). Moreover, Upregulated AEG-1 mRNA expression level was associated with higher tumor angiogenesis, reflected by the increase of VEGF expression and iMVD counting (P=0.021, P<0.001). However, 95D cell line transfected with AEG-1 siRNA oligos (siAEG-1) exhibited no significant decrease of cell invasion or migration capacities when compared with the control cells (P>0.05).These results suggested that AEG-1 may play important roles at the transcription level in malignant transformation and tumor angiogenesis in NSCLC, and anti-AEG-1 mRNA expression may be a novel potential strategy for anti-angiogenic therapy of NSCLC.