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Ndrg2 promoter hypermethylation triggered by helicobacter pylori infection correlates with poor patients survival in human gastric carcinoma.

Ling ZQ, Ge MH, Lu XX, Han J, Wu YC, Liu X, Zhu X, Hong LL - Oncotarget (2015)

Bottom Line: We found that Ndrg2 promoter was frequently hypermethylated in gastric cancer cell lines and in 292 gastric tumor tissues.This resulted in down-regulation of Ndrg2 mRNA and protein.We found that H. pylori silenced Ndrg2 by activating the NF-κB pathway and up-regulating DNMT3b, promoting gastric cancer progression.

View Article: PubMed Central - PubMed

Affiliation: Zhejiang Cancer Research Institute, Zhejiang Province Cancer Hospital, Zhejiang Cancer Center, Hangzhou, China.

ABSTRACT
N-myc downstream regulated gene 2 (Ndrg2) is a candidate suppressor of cancer metastasis. We found that Ndrg2 promoter was frequently hypermethylated in gastric cancer cell lines and in 292 gastric tumor tissues. This resulted in down-regulation of Ndrg2 mRNA and protein. Ndrg2 promoter methylation was associated with H. pylori infection and worse prognosis of gastric cancer patients, which is an independent prognostic factor for the disease-free survival (DFS). We found that H. pylori silenced Ndrg2 by activating the NF-κB pathway and up-regulating DNMT3b, promoting gastric cancer progression. These findings uncover a previously unrecognized role for H. pylori infection in gastric cancer.

No MeSH data available.


Related in: MedlinePlus

Expression of Ndrg2 is significantly reduced in gastric cancer cellsThe relative level of Ndrg2 transcript in gastric cancer cell lines in comparison with normal gastric mucosa epithelial tissues from patients undergoing gastroscope examination is shown in A1. Ndrg2 mRNA level was determined by RT-PCR and adjusted for Gapdh. The tumor/PCHNT ratio < 0.5 is considered as low expression and > 2 to be considered as high expression. The mRNA level of Ndrg2 in gastric cancer cell lines as determined by 2.0% agarose gel electrophoresis is shown in A2. The protein level of Ndrg2 in gastric cancer cell lines as determined by western blot (WB) is shown in A3. β-actin was internal reference. The Ndrg2 protein results by western blot compared with the Ndrg2 mRNA results by RT-PCR have the better consistency. Representative immunohistochemical (IHC) images of Ndrg2 expression are shown for normal gastric tissues (B1) and cancer tissues (B2). ×200 for all images. The protein level of Ndrg2 in 292 primary gastric cancer tissues as determined by IHC is shown in B3. IHC score of 0-4 is considered to be no to low expression and 5-12 considered to be normal to high expression. The level of Ndrg2 expression in PCHNTs is higher than that in tumor tissues (P<0.05). The protein level of Ndrg2 in thirty specimens of gastric cancer and paired normal gastric epithelium tissues as determined by WB is shown in C. Representative WB images of Ndrg2 expression are shown in C1, and in comparison with IHC results. β-actin was internal control. Western blot analysis of Ndrg2 protein showed that the differences between tumor and PCHNT groups were significant (P<0.05) (C2).
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Figure 1: Expression of Ndrg2 is significantly reduced in gastric cancer cellsThe relative level of Ndrg2 transcript in gastric cancer cell lines in comparison with normal gastric mucosa epithelial tissues from patients undergoing gastroscope examination is shown in A1. Ndrg2 mRNA level was determined by RT-PCR and adjusted for Gapdh. The tumor/PCHNT ratio < 0.5 is considered as low expression and > 2 to be considered as high expression. The mRNA level of Ndrg2 in gastric cancer cell lines as determined by 2.0% agarose gel electrophoresis is shown in A2. The protein level of Ndrg2 in gastric cancer cell lines as determined by western blot (WB) is shown in A3. β-actin was internal reference. The Ndrg2 protein results by western blot compared with the Ndrg2 mRNA results by RT-PCR have the better consistency. Representative immunohistochemical (IHC) images of Ndrg2 expression are shown for normal gastric tissues (B1) and cancer tissues (B2). ×200 for all images. The protein level of Ndrg2 in 292 primary gastric cancer tissues as determined by IHC is shown in B3. IHC score of 0-4 is considered to be no to low expression and 5-12 considered to be normal to high expression. The level of Ndrg2 expression in PCHNTs is higher than that in tumor tissues (P<0.05). The protein level of Ndrg2 in thirty specimens of gastric cancer and paired normal gastric epithelium tissues as determined by WB is shown in C. Representative WB images of Ndrg2 expression are shown in C1, and in comparison with IHC results. β-actin was internal control. Western blot analysis of Ndrg2 protein showed that the differences between tumor and PCHNT groups were significant (P<0.05) (C2).

Mentions: To investigate the candidacy of Ndrg2 as a suppressor in gastric progression, we initially characterized the expression status of Ndrg2 transcript in five gastric cancer cell lines. Ndrg2 mRNA expression is significant lower in 4 of 5 gastric cancer cell lines as compared to the average level of 40 normal gastric mucosas from healthy individuals examined (Figure 1 A1-A2); almost undetectable in HGC-27 cells and relative higher in SGC-7901 cells (Figure 1 A1-A2). Western blotting analysis validated the mRNA expression results, confirming that the Ndrg2 protein levels in the 4 cell lines are non-detectable (Figure 1 A3).


Ndrg2 promoter hypermethylation triggered by helicobacter pylori infection correlates with poor patients survival in human gastric carcinoma.

Ling ZQ, Ge MH, Lu XX, Han J, Wu YC, Liu X, Zhu X, Hong LL - Oncotarget (2015)

Expression of Ndrg2 is significantly reduced in gastric cancer cellsThe relative level of Ndrg2 transcript in gastric cancer cell lines in comparison with normal gastric mucosa epithelial tissues from patients undergoing gastroscope examination is shown in A1. Ndrg2 mRNA level was determined by RT-PCR and adjusted for Gapdh. The tumor/PCHNT ratio < 0.5 is considered as low expression and > 2 to be considered as high expression. The mRNA level of Ndrg2 in gastric cancer cell lines as determined by 2.0% agarose gel electrophoresis is shown in A2. The protein level of Ndrg2 in gastric cancer cell lines as determined by western blot (WB) is shown in A3. β-actin was internal reference. The Ndrg2 protein results by western blot compared with the Ndrg2 mRNA results by RT-PCR have the better consistency. Representative immunohistochemical (IHC) images of Ndrg2 expression are shown for normal gastric tissues (B1) and cancer tissues (B2). ×200 for all images. The protein level of Ndrg2 in 292 primary gastric cancer tissues as determined by IHC is shown in B3. IHC score of 0-4 is considered to be no to low expression and 5-12 considered to be normal to high expression. The level of Ndrg2 expression in PCHNTs is higher than that in tumor tissues (P<0.05). The protein level of Ndrg2 in thirty specimens of gastric cancer and paired normal gastric epithelium tissues as determined by WB is shown in C. Representative WB images of Ndrg2 expression are shown in C1, and in comparison with IHC results. β-actin was internal control. Western blot analysis of Ndrg2 protein showed that the differences between tumor and PCHNT groups were significant (P<0.05) (C2).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 1: Expression of Ndrg2 is significantly reduced in gastric cancer cellsThe relative level of Ndrg2 transcript in gastric cancer cell lines in comparison with normal gastric mucosa epithelial tissues from patients undergoing gastroscope examination is shown in A1. Ndrg2 mRNA level was determined by RT-PCR and adjusted for Gapdh. The tumor/PCHNT ratio < 0.5 is considered as low expression and > 2 to be considered as high expression. The mRNA level of Ndrg2 in gastric cancer cell lines as determined by 2.0% agarose gel electrophoresis is shown in A2. The protein level of Ndrg2 in gastric cancer cell lines as determined by western blot (WB) is shown in A3. β-actin was internal reference. The Ndrg2 protein results by western blot compared with the Ndrg2 mRNA results by RT-PCR have the better consistency. Representative immunohistochemical (IHC) images of Ndrg2 expression are shown for normal gastric tissues (B1) and cancer tissues (B2). ×200 for all images. The protein level of Ndrg2 in 292 primary gastric cancer tissues as determined by IHC is shown in B3. IHC score of 0-4 is considered to be no to low expression and 5-12 considered to be normal to high expression. The level of Ndrg2 expression in PCHNTs is higher than that in tumor tissues (P<0.05). The protein level of Ndrg2 in thirty specimens of gastric cancer and paired normal gastric epithelium tissues as determined by WB is shown in C. Representative WB images of Ndrg2 expression are shown in C1, and in comparison with IHC results. β-actin was internal control. Western blot analysis of Ndrg2 protein showed that the differences between tumor and PCHNT groups were significant (P<0.05) (C2).
Mentions: To investigate the candidacy of Ndrg2 as a suppressor in gastric progression, we initially characterized the expression status of Ndrg2 transcript in five gastric cancer cell lines. Ndrg2 mRNA expression is significant lower in 4 of 5 gastric cancer cell lines as compared to the average level of 40 normal gastric mucosas from healthy individuals examined (Figure 1 A1-A2); almost undetectable in HGC-27 cells and relative higher in SGC-7901 cells (Figure 1 A1-A2). Western blotting analysis validated the mRNA expression results, confirming that the Ndrg2 protein levels in the 4 cell lines are non-detectable (Figure 1 A3).

Bottom Line: We found that Ndrg2 promoter was frequently hypermethylated in gastric cancer cell lines and in 292 gastric tumor tissues.This resulted in down-regulation of Ndrg2 mRNA and protein.We found that H. pylori silenced Ndrg2 by activating the NF-κB pathway and up-regulating DNMT3b, promoting gastric cancer progression.

View Article: PubMed Central - PubMed

Affiliation: Zhejiang Cancer Research Institute, Zhejiang Province Cancer Hospital, Zhejiang Cancer Center, Hangzhou, China.

ABSTRACT
N-myc downstream regulated gene 2 (Ndrg2) is a candidate suppressor of cancer metastasis. We found that Ndrg2 promoter was frequently hypermethylated in gastric cancer cell lines and in 292 gastric tumor tissues. This resulted in down-regulation of Ndrg2 mRNA and protein. Ndrg2 promoter methylation was associated with H. pylori infection and worse prognosis of gastric cancer patients, which is an independent prognostic factor for the disease-free survival (DFS). We found that H. pylori silenced Ndrg2 by activating the NF-κB pathway and up-regulating DNMT3b, promoting gastric cancer progression. These findings uncover a previously unrecognized role for H. pylori infection in gastric cancer.

No MeSH data available.


Related in: MedlinePlus