The Expression Of MDR-1and PECAM-1in Human Lung Adenocarcinoma SPC-A-1Cell Lines Before And After High-dose X-ray Irradiation

Lung cancer is one of malignant tumors.which produces significant hazard to hu man health in today’s world.and is also the highest morbidity and mortality of mal ignant tumor.70to80percent of lung cancer is NSCLC.and the first diagnosis is advanced, unresectable.and comprehensive treatment of chemotherapy and radiation t herapy.but the effect is not good. Studies has shown that tumor multidrug resistance (multidrug resistance. MDR) is one of the important reason for the failure of canc er treatment, the most common multidrug resistance is MDR-1and its encoded prot ein p-gp-mediated drug resistance. Not only chemotherapy will cause the generation of multi-drug resistance, radiation therapy also can cause multidrug resistance. In o ur previous study of X-ray irradiation of nasopharyngeal carcinoma. MDR and plate let endothelial adhesion molecule associated, But the generation mechanism of MDR is not yet clear. Multidrug resistance gene express also in lung cancer. Breast canc er. Ovarian cancer.We infer that the platelet-endothelial adhesion molecules in lung adenocarcinoma SPC-A-1cell line may also be involved in the MDR, Therefore, th e expression and relationship of multidrug resistance and PECAM-1gene and protei n is studied in the lung adenocarcinoma SPC-A-1cell lines tumor.to provide a ne w direction for the further study of lung cancer MDR mechanisms.Objective:(1)The expression of MDR-1and its encoded P-gp was detected in lung adenocarcinoma SPC-A-1cell lines before and after high-dose X-ray irradiation, and to explore the relationship of the X-ray exposure and lung adenocarcinoma multidrug resistance.(2)The expression of PECAM-1and its encoded protein was detected in lung adenocarcinoma SPC-A-1cell lines before and after high-dose X-ray irradiation, to explore the relationship between X-ray irradiation with lung adenocarcinoma of PECAM-1 expression.(3)The expression of MDR-1and its encoded protein and PECAM-1and its protein-coding was compared, and to explore the relationship between the two.Methods:Cultured human lung adenocarcinoma SPC-A-1cell lines mimic the cli nical routine division of6MV X-ray irradiation using a linear accelerator-each irradi ation2GY.5times a week.total radiation20times, cumulative dose40GY.50%inhi bitory concentration of cisplatin for before and after X-ray irradiation SPC-A-1cell lines were detected by MTT assay. The changes of MDR-1and PECAM-1gene expression was detected in lung adenocarcinoma SPC-A-1cell lines before and after X-ray irradiation by RT-PCR.Lung adenocarcinoma SPC-A-1cell line of P-gp. as w ell as PECAM-1protein expression changes before and after the X-ray radiation wa s detected by immunofluorescence staining.Results:(1)IC50before and after the X-ray radiation in SPC-A-1cell lines was detected by MTT (0.523±0.018) μg/ml and (8.42±0.313)μg/ml of (P<0.05).difference was statistically significant;(2)MDR-1value of the semi-quantitative was respectively (0.22±0.02) and (0.58±0.03)(P<0.05) in SPC-A-1cell lines before and after X-ray irradiation by RT-PCR. and PECAM-1semi-quantitative were (0.43±0.01) and (0.80±0.04)(P <0.05). difference was statistically significant;(3)The positive rate of P-gp was (25.53±2.35) and (53.42±1.73)(P<0.05) in SPC-A-1cells before and after X-ray irradiation by immunofluorescence staining, PECAM-1-positive rates were (32.28±1.43) and (65.27±4.17)(P<0.05), difference was statistically significant.Conclusion:There is weak genes (MDR-1) and its encoded protein (P-gp) in th e lung adenocarcinoma SPC-A-1cell lines before X-ray irradiation, indicating that there is a certain amount of primary drug resistance in the parental generation of S PC-A-1cell lines. The IC50of SPC-A-1cell lines increases significantly after irrad iation than before irradiation.resulting in resistance; The expression of gene (MDR-1) and its encoded protein (P-gp) in the SPC-A-1cell lines is higher after X-ray i rradiation than before irradiation, indicating that X-ray irradiation induces MDR-1a nd its encoded protein p-gp expression.and induces resistance.as tip that PECAM-1 may be involved in MDR production.