ABSTRACT
Objective To investigate the effect of liver kinase B1(LKB1) on the radiosensitivity of subcutaneous xenograft tumor of lung cancer H460 cells in nude mice.Methods Human lung cancer H460 cells were implanted into female nude mice (BALB/c-nu) to establish a subcutaneous xenograft tumor model of lung cancer.A total of 24 female nude mice in which the model was successfully established were equally and randomly divided into four groups:pEGFP-Ctrl plasmid (empty vector plasmid) group, irradiation (IR)+pEGFP-Ctrl plasmid group, pEGFP-LKB1 plasmid (overexpressing LKB1) group, and IR+pEGFP-LKB1 plasmid group.The growth of xenograft tumors was observed and the tumor inhibition rate and enhancement factor (EF) were calculated.The expression of LKB1 in each group was measured by immunohistochemistry and Western blot to analyze the relationship between LKB1 and radiosensitivity.Results Compared with the pEGFP-Ctrl plasmid group, the IR+pEGFP-Ctrl plasmid group, pEGFP-LKB1 plasmid group, and IR+pEGFP-LKB1 plasmid group showed varying degrees of inhibition of tumor growth, particularly in the IR+pEGFP-LKB1 plasmid group, and the tumor inhibition rates were 31.30%, 14.78%, and 43.48%, respectively.The EF of LKB1 in the IR+pEGFP-LKB1 plasmid group was 1.18.The immunohistochemistry and Western blot showed that LKB1 could be effectively expressed in the pEGFP-LKB1 plasmid group and IR+pEGFP-LKB1 plasmid group, but not in the other two groups.Conclusions The subcutaneous xenograft tumor model of human lung cancer H460 cells has been successfully established in nude mice.LKB1 has a radiosensitizing effect on the subcutaneous xenograft tumor of lung cancer H460 cells in nude mice.
ABSTRACT
Objective To establish radiation?resistant lung carcinoma cell lines, and to investigate the changes in morphology, apoptosis, invasive migration, and epithelial?mesenchymal transition ( EMT) in cells. Methods The radiation?resistant lung carcinoma cell lines were obtained by exposure of lung carcinoma cell lines, A549 and H1299, to radiation with a low dose in fractions, a sublethal dose, or a gradually increasing dose. The morphological changes in cells, radiosensitivity, survival rates after exposure, apoptosis rates, changes in invasive migration, and expression of EMT marker proteins were evaluated using microscopy, colony formation assay, CCK?8 assay, flow cytometry, transwell migration assay, and Western blot, respectively. Results Radiation with a gradually increasing dose successfully induced the radiation?resistant cell lines, A549R and H1299R. The morphological study showed that the morphology of radiation?resistant cells was converted to the morphology of mesenchymal cells. Compared with A549 and H1299 cells, the values of D0 , Dq , and SF2 were significantly increased in A549R ( P=0.017,P=0.001,P=0.000) and H1299R (P=0.033,P=0.000,P=0.008) cells, respectively;the values of α and α/β were significantly reduced in A549R (P=0.018;P=0.007) and H1299R (P=0.001;P=0.009) cells, respectively. The survival rates in A549R and H1299R cells after exposure to radiation with various doses were significantly higher than those in the control groups (all P<0.05). After exposure, the apoptosis rates were significantly reduced in A549R and H1299R cells ( P=0.02,P=0.01);the invasion and migration rates were significantly increased in A549R (P=0.000;P=0.001) and H1299R (P=0.001,P=0.002) cells;the expression of E?cadherin was significantly down?regulated in A549R and H1299R cells (P=0.00,P=0.01), while the expression of vimentin was significantly elevated in A549R and H1299R cells ( P= 0. 02, P= 0. 01 ) . Conclusions The radiation?resistant lung carcinoma cell lines are successfully established. Both cell lines show enhanced invasion and migration, which may be associated with EMT.