Objective:To explore the effects of K-ras gene on the expressions of oncogenes and cancer suppressor genes in human bronchial epithelial (HBE) cells which were exposed to PM 2.5. Methods:According to the mRNA sequence of K-ras gene provided by GenBank in September 2019, interference sequences were designed and synthesized, and the recombinant lentiviral vector was transfected into HBE cell to construct the K-ras gene-silenced cells. HBE cells and K-ras gene-silenced cells were exposed to 10 μg/ml, 50 μg/ml PM 2.5 suspension and 10 μmol/L Cr 6+. Real-time fluorescent quantitative PCR was used to detect the mRNA expression levels of c-myc, c-fos, N-ras, cyclin-D1, p16 and p53 genes, the expression levels of p53 and c-myc proteins were detected by Western blot. Results:In K-ras silenced cell group, K-ras mRNA expression level decreased (80.5%±3.6%) and K-ras protein level decreased (58.9%±4.7%) when compared with the control group ( P<0.01) . Compared with the correspoding cell control group without exposure, the mRNA expression levels of c-myc, c-fos, N-ras and cyclin-D1 genes in HBE cell group exposed to different concentrations of PM 2.5, K-ras silenced cell group exposed to different concentrations of PM 2.5, HBE cell group exposed to 10 μmol/L Cr 6+ and K-ras silenced cell group exposed to 10 μmol/L Cr 6+ were increased, the mRNA expressions of p16 and p53 genes were decreased ( P<0.01) . Compared with HBE cell group exposed to 10 μg/ml PM 2.5, the mRNA expressions of c-myc, c-fos and p16 genes in K-ras silenced cells exposed to 10 μg/ml PM 2.5 were decreased, and the p53 mRNA level was increased ( P<0.01) . Compared with HBE cell group exposed to 50 μg/ml PM 2.5, the mRNA expression levels of c-fos, N-ras, cyclin-D1, p16 and p53 genes in K-ras silenced cell group exposed to 50 μg/ml PM 2.5 were decreased ( P<0.01) . Compared with the HBE cell group without exposure, c-myc protein increased and p53 protein decreased in HBE cells exposed to 50 μg/ml PM 2.5 ( P<0.05) . Compared with the K-ras silenced cell group without exposure, c-myc protein increased in K-ras silenced cells exposed to 50 μg/ml PM 2.5 ( P<0.05) . Conclusion:PM 2.5 can increase the expression levels of oncogenes in HBE cells, and K-ras gene silencing can inhibit the expression levels of oncogenes in HBE cells treated with PM 2.5.

Objective:To explore the effects of K-ras gene on the expressions of oncogenes and cancer suppressor genes in human bronchial epithelial (HBE) cells which were exposed to PM 2.5. Methods:According to the mRNA sequence of K-ras gene provided by GenBank in September 2019, interference sequences were designed and synthesized, and the recombinant lentiviral vector was transfected into HBE cell to construct the K-ras gene-silenced cells. HBE cells and K-ras gene-silenced cells were exposed to 10 μg/ml, 50 μg/ml PM 2.5 suspension and 10 μmol/L Cr 6+. Real-time fluorescent quantitative PCR was used to detect the mRNA expression levels of c-myc, c-fos, N-ras, cyclin-D1, p16 and p53 genes, the expression levels of p53 and c-myc proteins were detected by Western blot. Results:In K-ras silenced cell group, K-ras mRNA expression level decreased (80.5%±3.6%) and K-ras protein level decreased (58.9%±4.7%) when compared with the control group ( P<0.01) . Compared with the correspoding cell control group without exposure, the mRNA expression levels of c-myc, c-fos, N-ras and cyclin-D1 genes in HBE cell group exposed to different concentrations of PM 2.5, K-ras silenced cell group exposed to different concentrations of PM 2.5, HBE cell group exposed to 10 μmol/L Cr 6+ and K-ras silenced cell group exposed to 10 μmol/L Cr 6+ were increased, the mRNA expressions of p16 and p53 genes were decreased ( P<0.01) . Compared with HBE cell group exposed to 10 μg/ml PM 2.5, the mRNA expressions of c-myc, c-fos and p16 genes in K-ras silenced cells exposed to 10 μg/ml PM 2.5 were decreased, and the p53 mRNA level was increased ( P<0.01) . Compared with HBE cell group exposed to 50 μg/ml PM 2.5, the mRNA expression levels of c-fos, N-ras, cyclin-D1, p16 and p53 genes in K-ras silenced cell group exposed to 50 μg/ml PM 2.5 were decreased ( P<0.01) . Compared with the HBE cell group without exposure, c-myc protein increased and p53 protein decreased in HBE cells exposed to 50 μg/ml PM 2.5 ( P<0.05) . Compared with the K-ras silenced cell group without exposure, c-myc protein increased in K-ras silenced cells exposed to 50 μg/ml PM 2.5 ( P<0.05) . Conclusion:PM 2.5 can increase the expression levels of oncogenes in HBE cells, and K-ras gene silencing can inhibit the expression levels of oncogenes in HBE cells treated with PM 2.5.