Dissertation
Dissertation > Medicine, health > Oncology > Respiratory system tumors > Lung tumors

Epithelial-Mesenchymal Transition (EMT) and the Expressive Effect of Emt on microRNAs in Lung Cancer A549 Cells

Author WangHaiBing
Tutor ChenXiaoFeng
School Suzhou University
Course Thoracic Surgery
Keywords EMT microRNA lung cancer A549 cells
CLC R734.2
Type Master's thesis
Year 2011
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Background and Objective: In China, lung cancer has become the first cause of death in tumors, the invasion and metastasis of lung cancer is leading cause of death and recurrence for the patients; Cell epithelial - mesenchymal transition (epithelial-mesenchymal transitions, EMT) is a process in which the epithelial cells change into mesenchymal-type under a special-inducible factor. Many studies have shown that EMT plays an important role in the invasion and metastasis and the development of the lung cancer. microRNAs (miRNAs) are a class of small non-coding RNA molecules about 22nt newly discovered. It can regulate the gene expression levels in the post-transcriptional process by inhibiting the translation of the target genes or inducing mRNA degradation of the target gene. Some studies have found that EMT can regulate cell differentiation, cell proliferation and tumor development, invasion and metastasis. Investigating the epithelial–mesenchymal transition and the expressive effect of the epithelial–mesenchymal transition on microRNAs(miRNAs) in lung cancer A549 cells and providing a new idea to the study of the molecular mechanism of the invasion and metastasis and development of lung cancer is a objective of the study.Methods: In this study, Different concentration tranfroming growth factor beta-1(TGF-β1) induced lung cancer A549 cells to generate EMT; The morphology change before and after induction of A549 cells was observed under phase-contrast microscopy; The EMT relative protein changes were analysised by western blot; The expressive changes of miRNAs after EMT were detected by microRNA(miRNA) array; Real time quantitative RT-PCR was applied to verify the reliability of miRNA array results; The data was processed by SPSS16.0 statistical software, all data were processed by mean±standard deviation, using paired t test . ResIdts: The lung cancer A549 cells morphous prolongs and the cell-cell junction becomes raritas after EMT by TGF-β1 inducing ; The epithelial protein marker E-cadherin downregulated and the mesenchymal protein marker Vimentin and Fibronectin upregulated after EMT by TGF-β1 inducing; There were 51 miRNAs that the expressive difference was over twice and with statistics sense (p<0.05) after EMT by TGF-β1 inducing, of all, 18 up-regulated and 33 down-regulated, mir-33a and mir-193a-3p respectively down-regulated by 92.8% and 86.5%; Real time quantitative RT-PCR measured that mir-33a and mir-193a-3p respectively down-regulated by 73.1% and 56.6%.Condusion: TGF-β1 can induce the lung cancer A549 cells to generate EMT; EMT has an effect on the expression of microRNAs in the lung cancer A549 cells and microRNAs may regulate the invasion and metastasis of lung cancer by EMT.

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