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NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway

View Article: PubMed Central - PubMed

ABSTRACT

N-myc down-regulated gene 1 (NDRG1) has been shown to regulate tumor growth and metastasis in various malignant tumors and also to be dysregulated in esophageal squamous cell carcinoma (ESCC). Here, we show that NDRG1 overexpression (91.9%, 79/86) in ESCC tumor tissues is associated with poor overall survival of esophageal cancer patients. When placed in stable transfectants of the KYSE 30 ESCC cell line generated by lentiviral transduction with the ectopic overexpression of NDRG1, the expression of transducin-like enhancer of Split 2 (TLE2) was decreased sharply, however β−catenin was increased. Mechanistically, NDRG1 physically associates with TLE2 and β−catenin to affect the Wnt pathway. RNA interference and TLE2 overexpression studies demonstrate that NDRG1 fails to active Wnt pathway compared with isogenic wild-type controls. Strikingly, NDRG1 overexpression induces the epithelial mesenchymal transition (EMT) through activating the Wnt signaling pathway in ESCC cells, decreased the expression of E-cadherin and enhanced the expression of Snail. Our study elucidates a mechanism of NDRG1-regulated Wnt pathway activation and EMT via affecting TLE2 and  β-catenin expression in esophageal cancer cells. This indicates a pro-oncogenic role for NDRG1 in esophageal cancer cells whereby it modulates tumor progression.

No MeSH data available.


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NDRG1 overexpression was correlated with poor overall survival in esophageal cancer. (A) Expression of NDRG1 was analyzed by immunohistochemical analysis in TMAs containing 78 ESCC tumor and adjacent normal epithelial tissues, with duplicate cores used for each case. The majority of tumor areas strongly express NDRG1 in the cytoplasm. Magnification, 200×. (B) Kaplan-Meier curve combined with Log-rank analysis for patients with ESCC showing weak and strong NDRG1 expression. (C) NDRG1 expression in a subset of ESCC (T) and matched non-neoplastic surgical tissues (N) was analyzed by Western blot analysis. (D) Whole cell protein extracts from 9 esophageal cancer cell lines were subjected to protein gel blot analysis using antibodies against NDRG1. Quantitative values of relative NDRG1 levels were normalized to β-actin (mean ± SD).
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f0001: NDRG1 overexpression was correlated with poor overall survival in esophageal cancer. (A) Expression of NDRG1 was analyzed by immunohistochemical analysis in TMAs containing 78 ESCC tumor and adjacent normal epithelial tissues, with duplicate cores used for each case. The majority of tumor areas strongly express NDRG1 in the cytoplasm. Magnification, 200×. (B) Kaplan-Meier curve combined with Log-rank analysis for patients with ESCC showing weak and strong NDRG1 expression. (C) NDRG1 expression in a subset of ESCC (T) and matched non-neoplastic surgical tissues (N) was analyzed by Western blot analysis. (D) Whole cell protein extracts from 9 esophageal cancer cell lines were subjected to protein gel blot analysis using antibodies against NDRG1. Quantitative values of relative NDRG1 levels were normalized to β-actin (mean ± SD).

Mentions: To assess the levels of NDRG1 expression in ESCC and adjacent normal tissues, we analyzed NDRG1 expression in TMAs of ESCC using IHC staining. Of the 86 ESCC cases with 78 paired adjacent tissues were analyzed, 86 tumor and 77 adjacent tissues were informative. In the tumor tissues, 18 (20.9%) had weak, 29 (33.7%) had moderate and 32 (37.2%) had strong staining of NDRG1, while 7 (8.1%) cases had negative expression. In contrast, the proportions of weak, moderate, strong and negative staining of NDRG1 in adjacent non-tumor tissues were 66.2% (51/77), 6.5% (5/77), 1.3% (1/77) and 26.0% (20/77), respectively. The upregulation of NDRG1 in ESCC tumor tissues compared with the levels in normal tissues was statistically significant (chi-square test, P < 0.001). NDRG1 protein was detected in the cytoplasm of ESCC and normal cells, with a definitive pattern in most tissues (Fig. 1A). We further analyzed the correlation between NDRG1 expression and patient survival. As shown in Fig. 1B, the estimated overall median survival time was 12 months (95% CI, 9–15) in the strongly expressing NDRG1 (strong) group and 47 months (95% CI, 29–65) in the weakly expressing NDRG1 (weak) group. The Kaplan-Meier analysis indicated that patients from the NDRG1-strong subset had significantly shorter overall median survival times than those in the NDRG1-week subset (P < 0.001). However, NDRG1 positivity did not have a significant association with other clinic pathological factors, including gender, age, pathological grade, tumor diameter, tumor position, lymphatic metastasis and AJCC stage (Table 1).Figure 1.


NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway
NDRG1 overexpression was correlated with poor overall survival in esophageal cancer. (A) Expression of NDRG1 was analyzed by immunohistochemical analysis in TMAs containing 78 ESCC tumor and adjacent normal epithelial tissues, with duplicate cores used for each case. The majority of tumor areas strongly express NDRG1 in the cytoplasm. Magnification, 200×. (B) Kaplan-Meier curve combined with Log-rank analysis for patients with ESCC showing weak and strong NDRG1 expression. (C) NDRG1 expression in a subset of ESCC (T) and matched non-neoplastic surgical tissues (N) was analyzed by Western blot analysis. (D) Whole cell protein extracts from 9 esophageal cancer cell lines were subjected to protein gel blot analysis using antibodies against NDRG1. Quantitative values of relative NDRG1 levels were normalized to β-actin (mean ± SD).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036407&req=5

f0001: NDRG1 overexpression was correlated with poor overall survival in esophageal cancer. (A) Expression of NDRG1 was analyzed by immunohistochemical analysis in TMAs containing 78 ESCC tumor and adjacent normal epithelial tissues, with duplicate cores used for each case. The majority of tumor areas strongly express NDRG1 in the cytoplasm. Magnification, 200×. (B) Kaplan-Meier curve combined with Log-rank analysis for patients with ESCC showing weak and strong NDRG1 expression. (C) NDRG1 expression in a subset of ESCC (T) and matched non-neoplastic surgical tissues (N) was analyzed by Western blot analysis. (D) Whole cell protein extracts from 9 esophageal cancer cell lines were subjected to protein gel blot analysis using antibodies against NDRG1. Quantitative values of relative NDRG1 levels were normalized to β-actin (mean ± SD).
Mentions: To assess the levels of NDRG1 expression in ESCC and adjacent normal tissues, we analyzed NDRG1 expression in TMAs of ESCC using IHC staining. Of the 86 ESCC cases with 78 paired adjacent tissues were analyzed, 86 tumor and 77 adjacent tissues were informative. In the tumor tissues, 18 (20.9%) had weak, 29 (33.7%) had moderate and 32 (37.2%) had strong staining of NDRG1, while 7 (8.1%) cases had negative expression. In contrast, the proportions of weak, moderate, strong and negative staining of NDRG1 in adjacent non-tumor tissues were 66.2% (51/77), 6.5% (5/77), 1.3% (1/77) and 26.0% (20/77), respectively. The upregulation of NDRG1 in ESCC tumor tissues compared with the levels in normal tissues was statistically significant (chi-square test, P < 0.001). NDRG1 protein was detected in the cytoplasm of ESCC and normal cells, with a definitive pattern in most tissues (Fig. 1A). We further analyzed the correlation between NDRG1 expression and patient survival. As shown in Fig. 1B, the estimated overall median survival time was 12 months (95% CI, 9–15) in the strongly expressing NDRG1 (strong) group and 47 months (95% CI, 29–65) in the weakly expressing NDRG1 (weak) group. The Kaplan-Meier analysis indicated that patients from the NDRG1-strong subset had significantly shorter overall median survival times than those in the NDRG1-week subset (P < 0.001). However, NDRG1 positivity did not have a significant association with other clinic pathological factors, including gender, age, pathological grade, tumor diameter, tumor position, lymphatic metastasis and AJCC stage (Table 1).Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

N-myc down-regulated gene 1 (NDRG1) has been shown to regulate tumor growth and metastasis in various malignant tumors and also to be dysregulated in esophageal squamous cell carcinoma (ESCC). Here, we show that NDRG1 overexpression (91.9%, 79/86) in ESCC tumor tissues is associated with poor overall survival of esophageal cancer patients. When placed in stable transfectants of the KYSE 30 ESCC cell line generated by lentiviral transduction with the ectopic overexpression of NDRG1, the expression of transducin-like enhancer of Split 2 (TLE2) was decreased sharply, however&nbsp;&beta;&minus;catenin was increased. Mechanistically, NDRG1 physically associates with TLE2 and &beta;&minus;catenin to affect the Wnt pathway. RNA interference and TLE2 overexpression studies demonstrate that NDRG1 fails to active Wnt pathway compared with isogenic wild-type controls. Strikingly, NDRG1 overexpression induces the epithelial mesenchymal transition (EMT) through activating the Wnt signaling pathway in ESCC cells, decreased the expression of E-cadherin and enhanced the expression of Snail. Our study elucidates a mechanism of NDRG1-regulated Wnt pathway activation and EMT via affecting TLE2 and&nbsp;&nbsp;&beta;-catenin expression in esophageal cancer cells. This indicates a pro-oncogenic role for NDRG1 in esophageal cancer cells whereby it modulates tumor progression.

No MeSH data available.


Related in: MedlinePlus