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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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Ectopic overexpression of NDRG1 promotes tumor growth in vivo. (A) Tumor volume was measured every 2 to 3 d after subcutaneous inoculation with 5×106 cells/animal. KYSE 30 cells overexpressing NDRG1 (KYSE 30-NDRG1) enhanced the growth of the xenograft tumors compared with that of inoculations using parent cells (P < 0.001). (B) Photographs of the dissected xenografts using the same magnification scale. (C) Xenograft tissue was subjected to immunohistochemical analysis for NDRG1, MMP1, Ki67, β-catenin, TLE2 and E-cadherin, Scale bar, 100 μm.
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f0005: Ectopic overexpression of NDRG1 promotes tumor growth in vivo. (A) Tumor volume was measured every 2 to 3 d after subcutaneous inoculation with 5×106 cells/animal. KYSE 30 cells overexpressing NDRG1 (KYSE 30-NDRG1) enhanced the growth of the xenograft tumors compared with that of inoculations using parent cells (P < 0.001). (B) Photographs of the dissected xenografts using the same magnification scale. (C) Xenograft tissue was subjected to immunohistochemical analysis for NDRG1, MMP1, Ki67, β-catenin, TLE2 and E-cadherin, Scale bar, 100 μm.

Mentions: To examine whether NDRG1 ectopic overexpression could affect tumor growth in vivo, we performed in vivo experiments via subcutaneous transplantation of transduced cells into nude mice, whereby we compared tumor growth rates induced by KYSE 30-Vec and KYSE 30-NDRG1 cells in a xenograft model. As shown in Fig. 5A, the tumor growth rate of KYSE 30-NDRG1 cells was significantly faster than that of KYSE 30-Vec cells 20 d after inoculation by subcutaneous injection. We observed that the tumor size of NDRG1-overexpressing cells was much larger than that in the control group (Fig. 5B). Immunohistochemical analysis was investigated in xenograft sections. As shown in Fig. 5C, significantly higher NDRG1 levels were observed in the xenografts derived from NDRG1-overexpressing cells, indicating that NDRG1 overexpression was maintained during these in vivo experiments. MMP1 and Ki67 were highly upregulated in NDRG1-overexpressing xenografts compared with wild type xenografts. This result suggests that higher NDRG1 levels may induce Ki67 and MMP1 levels, which promote tumor growth in vivo, and is consistent with our in vitro data, in which NDRG1 overexpression significantly increased MMP1 at the transcript and protein expression levels.Figure 5.


NDRG1 overexpression promotes the progression of esophageal squamous cell carcinoma through modulating Wnt signaling pathway
Ectopic overexpression of NDRG1 promotes tumor growth in vivo. (A) Tumor volume was measured every 2 to 3 d after subcutaneous inoculation with 5×106 cells/animal. KYSE 30 cells overexpressing NDRG1 (KYSE 30-NDRG1) enhanced the growth of the xenograft tumors compared with that of inoculations using parent cells (P < 0.001). (B) Photographs of the dissected xenografts using the same magnification scale. (C) Xenograft tissue was subjected to immunohistochemical analysis for NDRG1, MMP1, Ki67, β-catenin, TLE2 and E-cadherin, Scale bar, 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036407&req=5

f0005: Ectopic overexpression of NDRG1 promotes tumor growth in vivo. (A) Tumor volume was measured every 2 to 3 d after subcutaneous inoculation with 5×106 cells/animal. KYSE 30 cells overexpressing NDRG1 (KYSE 30-NDRG1) enhanced the growth of the xenograft tumors compared with that of inoculations using parent cells (P < 0.001). (B) Photographs of the dissected xenografts using the same magnification scale. (C) Xenograft tissue was subjected to immunohistochemical analysis for NDRG1, MMP1, Ki67, β-catenin, TLE2 and E-cadherin, Scale bar, 100 μm.
Mentions: To examine whether NDRG1 ectopic overexpression could affect tumor growth in vivo, we performed in vivo experiments via subcutaneous transplantation of transduced cells into nude mice, whereby we compared tumor growth rates induced by KYSE 30-Vec and KYSE 30-NDRG1 cells in a xenograft model. As shown in Fig. 5A, the tumor growth rate of KYSE 30-NDRG1 cells was significantly faster than that of KYSE 30-Vec cells 20 d after inoculation by subcutaneous injection. We observed that the tumor size of NDRG1-overexpressing cells was much larger than that in the control group (Fig. 5B). Immunohistochemical analysis was investigated in xenograft sections. As shown in Fig. 5C, significantly higher NDRG1 levels were observed in the xenografts derived from NDRG1-overexpressing cells, indicating that NDRG1 overexpression was maintained during these in vivo experiments. MMP1 and Ki67 were highly upregulated in NDRG1-overexpressing xenografts compared with wild type xenografts. This result suggests that higher NDRG1 levels may induce Ki67 and MMP1 levels, which promote tumor growth in vivo, and is consistent with our in vitro data, in which NDRG1 overexpression significantly increased MMP1 at the transcript and protein expression levels.Figure 5.

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