Lipoxin A4 Ameliorates Lipopolysaccharide-Induced A549 Cell Injury through Upregulation of N-myc Downstream-Regulated Gene-1 / 中华医学杂志(英文版)

<p><b>Background</b>Lipoxin A4 (LXA4) can alleviate lipopolysaccharide (LPS)-induced acute lung injury (ALI) and acute respiratory distress syndrome through promoting epithelial sodium channel (ENaC) expression in lung epithelial cells. However, how LXA4 promote ENaC expression is still largely elusive. The present study aimed to explore genes and signaling pathway involved in regulating ENaC expression induced by LXA4.</p><p><b>Methods</b>A549 cells were incubated with LPS and LXA4, or in combination, and analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) of ENaC-α/γ. Candidate genes affected by LXA4 were explored by transcriptome sequencing of A549 cells. The critical candidate gene was validated by qRT-PCR and Western blot analysis of A549 cells treated with LPS and LXA4 at different concentrations and time intervals. LXA4 receptor (ALX) inhibitor BOC-2 was used to test induction of candidate gene by LXA4. Candidate gene siRNA was adopted to analyze its influence on A549 viability and ENaC-α expression. Phosphoinositide 3-kinase (PI3K) inhibitor LY294002 was utilized to probe whether the PI3K signaling pathway was involved in LXA4 induction of candidate gene expression.</p><p><b>Results</b>The A549 cell models of ALI were constructed and subjected to transcriptome sequencing. Among candidate genes, N-myc downstream-regulated gene-1 (NDRG1) was validated by real-time-PCR and Western blot. NDRG1 mRNA was elevated in a dose-dependent manner of LXA4, whereas BOC-2 antagonized NDRG1 expression induced by LXA4. NDRG1 siRNA suppressed viability of LPS-treated A549 cells (treatment vs. control, 0.605 ± 0.063 vs. 0.878 ± 0.083, P = 0.040) and ENaC-α expression (treatment vs. control, 0.458 ± 0.038 vs. 0.711 ± 0.035, P = 0.008). LY294002 inhibited NDRG1 (treatment vs. control, 0.459 ± 0.023 vs. 0.726 ± 0.020, P = 0.001) and ENaC-α (treatment vs. control, 0.236 ± 0.021 vs. 0.814 ± 0.025, P < 0.001) expressions and serum- and glucocorticoid-inducible kinase 1 phosphorylation (treatment vs. control, 0.442 ± 0.024 vs. 1.046 ± 0.082, P = 0.002), indicating the PI3K signaling pathway was involved in regulating NDRG1 expression induced by LXA4.</p><p><b>Conclusion</b>Our research uncovered a critical role of NDRG1 in LXA4 alleviation of LPS-induced A549 cell injury through mediating PI3K signaling to restore ENaC expression.</p>

Preliminary study of NDRG1 gene promoter methylation status in prostate cancer / 中华泌尿外科杂志

Objective To evaluate the methylation status of prostate cancer NDRG1 gene promoter region,and to explore the influence of methylation inhibitor 5-azacytidine on NDRG1 gene's mRNA expression in prostate cancer cells and its effects on cell proliferation.Methods Bisulfite-sequencing PCR (BSP) were used to detect the NDRG1 gene promoter methylation status in prostate cancer and BPH tissue,prostate cancer cell lines (PC3,22RV1,LNCaP and DU145) and human normal prostate cell line's RWPE-1.After 10 μmol/L 5-azacytidine were used on LNCaP and DU145 cells for 72 h,5-azacytidine's influence on cell proliferation was analyzed with MTT,two prostate cancer cell lines NDRG1 mRNA expressions were detected with RT-PCR.Results The methylation rates of NDRG1 gene in prostate cancer cell lines PC-3,22RV1,LNCaP and DU145 were (24.8 ± 3.3) ％,(36.2 ± 2.5) ％,(48.6 ± 2.8) ％ and (69.5 ± 1.7) ％,respectively.Methylation rate of Human normal prostate cell lines RWPE-1 was (4.8 ± 4.5) ％;prostate carcinoma was (48.6 ± 5.3) ％,BPH tissue was (4.3 ± 2.1) ％.The differences between groups were statistically significant.After 10 μmol/L 5-azacytidine added on LNCaP and DU145 cells for 72 h,NDRG1 gene demethylation occurred in both cells,its mRNA expression enhanced 8-9 times compared with previous and its cell growth was inhibited (P ＜ 0.05).Conclusions NDRG1 gene promoter region's hypermethylation is one of the reasons of its aberrant expression in prostate cancer.5-azacytidine can reverse NDRG1 gene promoter methylation status,regulate the expression of the gene and can inhibit prostate cancer cell proliferation.

Expression of N-myc downstream regulated gene 1 in breast invasive duct carcinoma and its relationship with tumor metastasis and invasive potential / 上海第二医科大学学报

Objective To study the correlation of expression of N-myc downstream regulated gene 1(NDRG1) with invasion of breast invasive duct carcinoma and lymph node metastasis. Methods A total of 71 specimens including 26 case of primary breast invasive duct carcinoma with lymphnode metastasis,45 case of nonmetastasis breast invasive duct carcinoma were observed.NDRG1 was detected by immunohistochemistry in formalin-fixed and paraffin-embedded sections.At the same time,the correlations of NDRG1 with E-cad,MMP2,MMP9,and TIMP2 were investigated. Results The expression of NDRG1 in breast cancer with metastasis of lymph nodes(9/26) was lower than that of non-metastasis of lymph nodes(32/45)(P