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Astrocyte elevated gene-1(AEG-1) induces epithelial-mesenchymal transition in lung cancer through activating Wnt/β-catenin signaling.

He W, He S, Wang Z, Shen H, Fang W, Zhang Y, Qian W, Lin M, Yuan J, Wang J, Huang W, Wang L, Ke Z - BMC Cancer (2015)

Bottom Line: In the present study, we demonstrated that astrocyte elevated gene-1(AEG-1) ectopic overexpression promoted EMT, which resulted from the down-regulation of E-cadherin and up-regulation of Vimentin in lung cancer cell lines and clinical lung cancer specimens.Using an orthotopic xenograft-mouse model, we also observed that AEG-1 overexpression in human carcinoma cells led to the development of multiple lymph node metastases and elevated mesenchymal markers such as Vimentin, which is a characteristic of cells in EMT.Furthermore, AEG-1 functioned as a critical protein in the regulation of EMT by directly targeting multiple positive regulators of the Wnt/β-catenin signaling cascade, including GSK-3β and CKIδ.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastrointestinal Surgery, Guangzhou, 510080, Province Guangdong, Peoples' Republic of China. heweiling@mail.sysu.edu.cn.

ABSTRACT

Background: Non-small cell lung cancer (NSCLC) is a highly metastatic cancer with limited therapeutic options, so development of novel therapies that target NSCLC is needed. During the early stage of metastasis, the cancer cells undergo an epithelial-mesenchymal transition (EMT), a phase in which Wnt/β-catenin signaling is known to be involved. Simultaneously, AEG-1 has been demonstrated to activate Wnt-mediated signaling in some malignant tumors.

Methods: Human NSCLC cell lines and xenograft of NSCLC cells in nude mice were used to investigate the effects of AEG-1 on EMT. EMT or Wnt/β-catenin pathway-related proteins were characterized by western blot, immunofluorescence and immunohistochemistry.

Results: In the present study, we demonstrated that astrocyte elevated gene-1(AEG-1) ectopic overexpression promoted EMT, which resulted from the down-regulation of E-cadherin and up-regulation of Vimentin in lung cancer cell lines and clinical lung cancer specimens. Using an orthotopic xenograft-mouse model, we also observed that AEG-1 overexpression in human carcinoma cells led to the development of multiple lymph node metastases and elevated mesenchymal markers such as Vimentin, which is a characteristic of cells in EMT. Furthermore, AEG-1 functioned as a critical protein in the regulation of EMT by directly targeting multiple positive regulators of the Wnt/β-catenin signaling cascade, including GSK-3β and CKIδ. Notably, overexpression of AEG-1 in metastatic cancer tissues was closely associated with poor survival of NSCLC patients.

Conclusions: These results reveal the critical role of AEG-1 in EMT and suggest that AEG-1 may be a prognostic biomarker and its targeted inhibition may be utilized as a novel therapy for NSCLC.

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Kaplan-Meier survival curves according to AEG-1 and EMT status, and corresponding Receiver Operating Characteristic analysis. (A) The high AEG-1 group correlated with poor survival of lung cancer patients. (B) In the AEG-1-positive group, EMT(+) status showed a poor survival trend. Patients with E-cadherin (−) and Vimentin(+) were evaluated as EMT(+); Conversely, patients with E-cadherin (+) and Vimentin(−) were evaluated as EMT(−). (C) In the AEG-1-negative group, EMT(+) status also showed a poor survival trend. (D) The combined AEG-1 and EMT status had the largest area under the curve compared with AEG-1 level and EMT status, respectively. (E) AEG-1 mRNA was determined by real-time RT-PCR in tumors with metastasis (n = 30) and those without metastasis (n = 23) and levels of AEG-1 mRNA were expressed as (AEG-1/β-actin mRNA ratio). *P < 0.05 versus nonmetastatic tissues.
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Fig7: Kaplan-Meier survival curves according to AEG-1 and EMT status, and corresponding Receiver Operating Characteristic analysis. (A) The high AEG-1 group correlated with poor survival of lung cancer patients. (B) In the AEG-1-positive group, EMT(+) status showed a poor survival trend. Patients with E-cadherin (−) and Vimentin(+) were evaluated as EMT(+); Conversely, patients with E-cadherin (+) and Vimentin(−) were evaluated as EMT(−). (C) In the AEG-1-negative group, EMT(+) status also showed a poor survival trend. (D) The combined AEG-1 and EMT status had the largest area under the curve compared with AEG-1 level and EMT status, respectively. (E) AEG-1 mRNA was determined by real-time RT-PCR in tumors with metastasis (n = 30) and those without metastasis (n = 23) and levels of AEG-1 mRNA were expressed as (AEG-1/β-actin mRNA ratio). *P < 0.05 versus nonmetastatic tissues.

Mentions: To explore the prognostic value of AEG-1 in patients, we used the Kaplan-Meier method to evaluate the relationship between the survival curve and AEG-1 expression, as well as EMT status. Survival analysis data indicated a significantly inverse correlation between AEG-1 protein expression level and the overall survival time (p < 0.001), clearly disclosing that higher levels of AEG-1 expression were associated with shorter survival time. As shown in Figure 7A, the cumulative 5-year survival rate was 37.8% (95% CI: 25.8%–49.8%) in the AEG-1 low expression group, whereas it was only 5.3% (95% CI: 4.2%–6.4%) in the AEG-1 high expression group.Figure 7


Astrocyte elevated gene-1(AEG-1) induces epithelial-mesenchymal transition in lung cancer through activating Wnt/β-catenin signaling.

He W, He S, Wang Z, Shen H, Fang W, Zhang Y, Qian W, Lin M, Yuan J, Wang J, Huang W, Wang L, Ke Z - BMC Cancer (2015)

Kaplan-Meier survival curves according to AEG-1 and EMT status, and corresponding Receiver Operating Characteristic analysis. (A) The high AEG-1 group correlated with poor survival of lung cancer patients. (B) In the AEG-1-positive group, EMT(+) status showed a poor survival trend. Patients with E-cadherin (−) and Vimentin(+) were evaluated as EMT(+); Conversely, patients with E-cadherin (+) and Vimentin(−) were evaluated as EMT(−). (C) In the AEG-1-negative group, EMT(+) status also showed a poor survival trend. (D) The combined AEG-1 and EMT status had the largest area under the curve compared with AEG-1 level and EMT status, respectively. (E) AEG-1 mRNA was determined by real-time RT-PCR in tumors with metastasis (n = 30) and those without metastasis (n = 23) and levels of AEG-1 mRNA were expressed as (AEG-1/β-actin mRNA ratio). *P < 0.05 versus nonmetastatic tissues.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4358870&req=5

Fig7: Kaplan-Meier survival curves according to AEG-1 and EMT status, and corresponding Receiver Operating Characteristic analysis. (A) The high AEG-1 group correlated with poor survival of lung cancer patients. (B) In the AEG-1-positive group, EMT(+) status showed a poor survival trend. Patients with E-cadherin (−) and Vimentin(+) were evaluated as EMT(+); Conversely, patients with E-cadherin (+) and Vimentin(−) were evaluated as EMT(−). (C) In the AEG-1-negative group, EMT(+) status also showed a poor survival trend. (D) The combined AEG-1 and EMT status had the largest area under the curve compared with AEG-1 level and EMT status, respectively. (E) AEG-1 mRNA was determined by real-time RT-PCR in tumors with metastasis (n = 30) and those without metastasis (n = 23) and levels of AEG-1 mRNA were expressed as (AEG-1/β-actin mRNA ratio). *P < 0.05 versus nonmetastatic tissues.
Mentions: To explore the prognostic value of AEG-1 in patients, we used the Kaplan-Meier method to evaluate the relationship between the survival curve and AEG-1 expression, as well as EMT status. Survival analysis data indicated a significantly inverse correlation between AEG-1 protein expression level and the overall survival time (p < 0.001), clearly disclosing that higher levels of AEG-1 expression were associated with shorter survival time. As shown in Figure 7A, the cumulative 5-year survival rate was 37.8% (95% CI: 25.8%–49.8%) in the AEG-1 low expression group, whereas it was only 5.3% (95% CI: 4.2%–6.4%) in the AEG-1 high expression group.Figure 7

Bottom Line: In the present study, we demonstrated that astrocyte elevated gene-1(AEG-1) ectopic overexpression promoted EMT, which resulted from the down-regulation of E-cadherin and up-regulation of Vimentin in lung cancer cell lines and clinical lung cancer specimens.Using an orthotopic xenograft-mouse model, we also observed that AEG-1 overexpression in human carcinoma cells led to the development of multiple lymph node metastases and elevated mesenchymal markers such as Vimentin, which is a characteristic of cells in EMT.Furthermore, AEG-1 functioned as a critical protein in the regulation of EMT by directly targeting multiple positive regulators of the Wnt/β-catenin signaling cascade, including GSK-3β and CKIδ.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastrointestinal Surgery, Guangzhou, 510080, Province Guangdong, Peoples' Republic of China. heweiling@mail.sysu.edu.cn.

ABSTRACT

Background: Non-small cell lung cancer (NSCLC) is a highly metastatic cancer with limited therapeutic options, so development of novel therapies that target NSCLC is needed. During the early stage of metastasis, the cancer cells undergo an epithelial-mesenchymal transition (EMT), a phase in which Wnt/β-catenin signaling is known to be involved. Simultaneously, AEG-1 has been demonstrated to activate Wnt-mediated signaling in some malignant tumors.

Methods: Human NSCLC cell lines and xenograft of NSCLC cells in nude mice were used to investigate the effects of AEG-1 on EMT. EMT or Wnt/β-catenin pathway-related proteins were characterized by western blot, immunofluorescence and immunohistochemistry.

Results: In the present study, we demonstrated that astrocyte elevated gene-1(AEG-1) ectopic overexpression promoted EMT, which resulted from the down-regulation of E-cadherin and up-regulation of Vimentin in lung cancer cell lines and clinical lung cancer specimens. Using an orthotopic xenograft-mouse model, we also observed that AEG-1 overexpression in human carcinoma cells led to the development of multiple lymph node metastases and elevated mesenchymal markers such as Vimentin, which is a characteristic of cells in EMT. Furthermore, AEG-1 functioned as a critical protein in the regulation of EMT by directly targeting multiple positive regulators of the Wnt/β-catenin signaling cascade, including GSK-3β and CKIδ. Notably, overexpression of AEG-1 in metastatic cancer tissues was closely associated with poor survival of NSCLC patients.

Conclusions: These results reveal the critical role of AEG-1 in EMT and suggest that AEG-1 may be a prognostic biomarker and its targeted inhibition may be utilized as a novel therapy for NSCLC.

Show MeSH
Related in: MedlinePlus