Radiosensition Of A Human Non-Small Lung Cancer Cell Line A₅₄₉ By Endostatin

Non-small cell lung cancer(NSCLC) is one of the most common malignant tumor in our world.There is increased morbidity and mortality trends,seriously endangering the most people's health.The NSCLC need a combined therapy. Traditional surgery and chemotherapy have their own limitations,leading to the clinical treatment effect is not satisfied with it.Radiotherapy plays an important role in the treatment of malignancies,and it is involved in about 70%of total malignancies. The outcome of radiation therapy depends on the radiosensitivity of tumor cells and the tolerance of the tissue bed to radiation.The effect of radiation in some malignancies,including Non-small cell lung cancer,is not very satisfactory because of significant short-term and long-term toxicity.Radiosensitizing agents can enhance the killing effect of radiation to tumor cells,and is an important way to increace radiotherapy outcome without significant complications.Many reports said that Endostatin,as an anti VEGF suppressor,could be combined with radiotherapy in many tumor model.It approved a local control in tumor growth,instead of toxical effect to normal cells,but the possible mechanizm of this phenomenon was still unknown.A₅₄₉,a lung cancer cell line,was used for our studies.We discussed the radio-sensitivity of Endostatin treated A₅₄₉ and provided evidence of utilizing Endostatin in NSCLC treatmentObjective:To study the synergistic effect of Endostatin(YH-16) and irradiation on human non-small cell lung cancer(NSCLC) cell line A₅₄₉ and the expression level of vascular endothefial growth factor.Methods:A₅₄₉ cells were exposed to various concentrations of Endostatin for different time.The optimal concentration giving≤20%inhibition concentration(IC20) by MTT assay was selected.The cells were divided into 4 groups:control group, chemotherapy alone,radiotherapy alone,and radio-chemotherapy group.All groups were exposed in distinct treatment,the cells survival fraction and the plating efficiency of the four groups provided to select the optimal radiotherapy dosage.The radio-chemotherapy group had been exposed in Endostatin for 48 hours,followed by irradiation at 48 hours with various doses:0,2,4,6,8Gy.After 14 days,the cell clonogenic survival curves and the SER were evaluated.Detect the different groups' VEGF value by ELISA kit.Results Incubating cells in 200mg/l Endostatin culture medium the value of SER radiated by linear accelerator in 2Gy after 48h were 1.61 and 1.04.And Endostatin with proper dosage and radio-exposure time could decreased the VEGF level.Conclusions:It is suggested that Endostatin enhances the radiosensitivity of NSCLC A₅₄₉ cell line in vitro(SER=1.61,1.04).The enhancement depends on the exposure time to the drug.The optimal radiation time should be 48 hour after exposure.