The Influence Of Hypoxia On Metastasis Induced By Epithelial-Mesenchymal Transition Of Human Lung Adenocarcinoma A549Cell Spheres

Lung cancer is one of the most common malignant tumor in China.High degreeof malignancy, early metastasis, insensitive to radiotherapy and chemotherapy andhigh mortality are its features, among which transfer is one of the leading causes ofdeath in patients with lung cancer.In recent years, the doctrine of cancer stem cells (CSC) and the progress hasmade in this area give people a new train of thought to realize the occurrence, thedevelopment, the metastasis and the recurrence of tumor. Some scholars put forwardfurther the concept of migrating cancer stem cells (MCSC) according to the decisiverole which the tumor stem cells play in the process of tumor metastasis. Theenvironment of hypoxia exist in the vast majority of solid tumors. Hypoxia has beenreported play a catalytic role in tumor metastasis; However, the metastatic capacitycharacteristics for CSC in a hypoxic environment is still a lack of relevant research.This experiment was designed to observe the hypoxic microenvironment factorsstimulate epithelial-mesenchymal transition (EMT) mechanisms to promote themetastasis of human lung adenocarcinoma A549cell spheres.Objective: To investigate the influence of hypoxia on metastasis induced byepithelialmesenchymal transition of human lung adenocarcinoma A549cell spheres.Methods: A549cell spheres were formed through serum-free culture. Theexpression levels of E-cadherin and vimentin in the parental A549cells and A549sphere cells under hypoxia condition for24h were examined by immunofluorescence,Western blotting, and reverse transcription (RT)-PCR, and compared with theexpressions levels under normoxia condition.Results: Under hypoxia and normoxia conditions, the expression levels ofE-cadherin mRNA and protein in the A549cells spheres were lower than those in theparental A549cells, but the expression levels of vimentin mRNA and protein in the A549cell spheres were increased. As compared with the normoxic condition, theexpression levels of E-cadherin mRNA and protein in the parental A549cells and theA549cell spheres were all down-regulated under hypoxic condition, and especiallyfor the parental A549cells, this decline was much more obvious; while the expressionlevel of vimentin was increased.Conclusion: A549cell spheres have a stronger ability of metastasis than theparental A549cells. This ability of metastasis is also stronger in the A549cell spheresunder hypoxic condition than that in the parental A549cells under normoxia.