Expression Of HO-1and Its Effect On Vegf In The Cells And Tissues Of Human Non-small Cell Lung Cancer

Objective:Lung,which communicates human body with ambient air, is usually attacked by stimulating gas, virus, bacterium, allergen and atmospheric pollutants, which can induce lung produce active oxygen-like material, cause lung damage and even to induce lung cancer occur. Therefore, the lung need a stronger defense mechanism and high-level antioxidase,ex:HO-1(heme oxygenase-1).HO-1,also known as Hsp32(heat shock protein-32),is an important inducible anti-oxidant enzyme and hemoglobin metabolic rate-limiting enzyme.HO-1can resolve hemoglobin into biliverdin, CO and iron, and then biliverdin be reduced to bilirubin by biliverdin reductase, and iron be combined together with transferrin. Both HO-1and its catabolites are antioxygen, which can protect cell and tissue against stress reaction. However, the protection function of HO-1is non-selectional. It can protects both the normal cells and the tumor cells. Now many studies about tumors have detected the high expression of HO-1,the induction and expression of which are related with the development, growth and metastasis of entity tumors.HO-1also be regarded as an enzyme promoting angiogenesis. Angiogenesis is a process of the new blood vessel generating on the ground of the inhere blood vessel, which takes the key point in the growth and diffusion of tumors. When the diameter of tumor up to2mm, it must rely on the formation of new blood vessels to continue to grow. Through promoting angiogenesis role, HO-1promotes the progression of tumor. Vascular endothelial growth factor(VEGF) is considered to be the strongest angiogenic factor, the expression level of VEGF reflects the level of tumor vascular endothelial cells proliferation, migration and blood vessels construction. The objective of this study is to investigate the expression of heme oxygenase-1, and its effect on VEGF expression in the cells and tissues of non-small cell lung cancer and probable mechanism.Methods:1. Choosing lung adenocarcinoma cell line A549and squamous cell line SK-MES-1as the research object, immortalized bronchial epithelial cell line HBE as control, the three kinds of cell lines are cultured in the incubator of37℃,5%CO2and100%humidity.2. Choose lung cancer (33cases of adenocarcinoma, squamous cell carcinoma in12cases) as the research object, immortalized normal tissues as control by the cancer compared to normal tissues3. MTT method is used to detect cell proliferation activity.4. Using quantitative RT-PCR (qRT-PCR) method detects the expression of HO-1and VEGF gene in the cells and tissues of non-small cell lung cancer.5. The Western Blotting method is used to detect the expression of HO-1protein in the cells and tissues of non-small cell lung cancer.Results:1. The three kinds of cells’ proliferation activityIn MTT experiments, OD value reflects the activity of cell metabolism. Relative to HBE, the OD value of both A549and SK-MES-1are significantly higher (P<0.05). The OD value has no obvious difference between A549with SK-MES-1(P>0.05).2. The qRT-PCR results of cell linesHO-1mRNA (P<0.05) has obviously increased expression in human lung caner cell lines compared to HBE, and HO-1mRNA has a higher level in A549than in SK-MES-1(P<0.05).VEGF mRNA expression also increased in A549and SK-MES-1compared to HBE (P<0.05), and the increasing expression of HO-1and VEGF correlated in two lung cancer cell lines (the correlation coefficient are1.35(P <0.01) and9.80(P<0.01).respectively.)3. Lung cancer and normal tissue qRT-PCR resultsHO-1mRNA has a obviously increased expression in human lung caner tissues compared to normal tissues (P<0.05), in smokers’ lung cancer tissues compared to non-smokers’(P<0.05).VEGF mRNA expression also increased in human lung caner tissues compared to normal tissues (P<0.05), and the increasing expression of HO-1and VEGF correlated in lung cancer tissues (correlation coefficient is0.87(P<0.01))).4. The expression of HO-1protein in Cells and tissuesHO-1protein has a higher level in A549and SK-MES-1than in HBE, in human lung caner tissues than in normal tissues.Conclusion:Our data shows that HO-1expression increases in the cells and tissues of non-small cell lung cancer, and plays an important role in VEGF synthesis.Its probable mechanism is that HO-1promotes angiogenesis by enhancing the expression of VEGF, thereby effecting the growth and metastasis of lung cancer.