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MINI 34 - RNA and miRNA (ID 162)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
MINI34.08 - MiR-33B Inhibit EMT Through Wnt/β-Catenin/ZEB1 Pathway in Lung Adenocarcinoma (ID 236)
18:30 - 20:00 | Author(s): L.M. Cao
Lung adenocarcinoma is one of the main pathological tissue types of lung small cell lung cancer (NSCLC). Tumor metastases are responsible for approximately 90% of lung adenocarcinoma-related death. The epithelial–mesenchymal transition (EMT) is regarded as a critical event during tumor metastasis. From our previous study, we found miR-33b might be involved in the EMT process of lung adenocarcinoma. However, the specific mechanism of miR-33b regulating EMT has not been established.
Quantitative real time-PCR (qRT-PCR), in situ hybridization and immunohistochemistry were used to investigate expression of miR-33b and ZEB1 in paired lung adenocarcinoma tissues. MiR-33b target gene ZEB1 was investigated using luciferase reporter gene assays. Western blot, qRT-PCR, immunofluorescence were used to compare the expression levels of ZEB1, E-cad, Vim and β-catenin in A549 cells which were transfected miR-33b or miR-NC, anti-miR-33b or anti-miR-NC and in vivo. MTT was used to analysis growth curves of transfected cells with miR-33b or miR-NC, anti-miR-33b or anti-miR-NC, siRNA-NC or siRNA -ZEB1, siRNA-NC or siRNA-β-catenin. The transfected cells were subjected to Transwell migration and invasion assays.
Mean miR-33b levels were significantly lower in lung adenocarcinoma tissues compared with matched non-cancerous tissues (0.024± 0.028 vs 0.063 ± 0.074, P < 0.0001). The level of miR-33b in NSCLC was strongly correlated with lymph node metastasis (P < 0.0001). ZEB1 levels were significantly higher in lung adenocarcinoma tissues compared with matched non-cancerous tissues (0.447± 0.371vs0.084 ± 0.112, P <0.0001). The level of miR-33b in lung adenocarcinoma was negative correlated with ZEB1 (P < 0.0001,r=-0.6077). MiR-33b significantly inhibited EMT in lung adenocarcinoma metastasis in vitro and vivo (P < 0.05).MiR-33b directly targets the ZEB13[']UTR(P < 0.01).β-catenin was down regulation by overexpression of miR-33b (P < 0.01). MiR-33b overexpression and ZEB1 inhibition suppressed lung adenocarcinoma migration and invasion in vitro (P < 0.01).
On the basis of our results, we propose that miR-33b suppress EMT in lung adenocarcinoma through direct targeting of ZEB1 in vitro and in vivo. Moreover, we found that Wnt/β-catenin/ZEB1 pathway regulated by miR-33b might involved in lung adenocarcinoma EMT. These findings provide new insights into the molecular functions of miR-33b as well asthe role of ZEB1 in lung adenocarcinoma metastasis.
P1.05 - Poster Session/ Prevention and Tobacco Control (ID 215)
- Event: WCLC 2015
- Type: Poster
- Track: Prevention and Tobacco Control
- Presentations: 1
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
P1.05-009 - EGCG Regulated Ku70 Acetylation for Apoptosis in Human Lung Cancer A549 Cells (ID 194)
09:30 - 17:00 | Author(s): L.M. Cao
Lung cancer is one of the malignant tumors whose global incidence and mortality are very high. The chemoprevention has become an important prevention and control means of lung cancer except for giving up smoking and early detection. Research has showed the main component in green tea (-)-epigallocatechin-3-gallate (EGCG) is a potential chemopreventive agent for various tumors, especially lung cancer.
The cells in each group were treated with different concentrations of EGCG for a certain time in the experiment. Two gene point mutation plasmid were constructed and transfected in A549 cells. Induction of apoptosis was examined using AnnexinV/Pl double staining flow cytometry. Western Blot detected the protein expressions of Bax, Bcl-xl and Caspase-3. Co-immunoprecipitation was used to detect the interaction of Ku70-Bax and acetylation status of Ku70. P<0.05 showed the difference had statistical significance.
Treatment of A549 cells with EGCG induced apoptosis with increasing expression of Bax and Caspase-3, but decreasing expression of Bcl-xl. EGCG could up-regulate K70 acetylation status of A549 cells，then down-regulate the interaction of Bax-Ku70 in the manner of concentration and time dependent. The apoptosis-promoting effect of EGCG on A549 cells was obviously weakened with the interaction of Bax-Ku70 strengthened and Caspase-3 (17KDa) expression declining after pCDNA3.1(+)-Ku70 plasmid and pCDNA3.1(+) -Ku70[539/542R] plasmid transfection.
The authors induced apoptosis in human lung adenocarcinoma A549 cells after treatment with EGCG, and it was realized by interfering the interaction between Ku70 and Bax through regulating K70 acetylation. It verified that two loci K539 and K542 of Ku70 acetylation might play a crucial role in EGCG inducing apoptosis of A549 cells.
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