Screening radiosensitizing-related genes mediated by elemene in lung adenocarcinoma A549 cells by using gene chip

Objective: To screen radiosensitizing-related genes mediated by elemene in lung adenocarcinoma A549 cells by using gene chip. Methods: MTT test was used to calculate the IC₅₀ of elemene. (1) The effect of radiosensitivity was detected by colony forming assay. A549 cells were divided into 2 groups: radiation group and radiation + elemene group. Oligonucleotide chip was used to screen the gene expression changes of A549 cells from these 2 groups. The up-regulated gene Egr-1 and the down-regulated gene CyclinD1 were selected to undergo RT-PCR so as to confirm the reliability of the result. Results: MTT test showed the elemene inhibited the proliferation of the A549 cells dose-dependently. The IC₅₀ value of elemene on the A549 cells was 120 mg/L. (2) 10 mg/L elemene had radiosensitising effect on A549 cells.The values of SER_D0 and SER_Dq obtained from the survival curve were (1.54±0. 20) and (1.43±0.15) respectively. Gene chip screened 122 differentially-expressed genes, including 89 up-regulated genes and 33 down-regulated genes. (3) These altered genes could be related to cell structure, substance metabolism,cell proliferation, cell differentiation, signal transduction, material transport, DNA repair, apoptosis, immune response and so forth. The RT-PCR results of Egr-1 and Cyclin D1 were consistent with the gene chip analysis. Conclusions: The mechanism of elemene enhancing the radiosensitivity of lung adenocarcinoma A549 cells is the result of participation and collaboration of multiple genes. Further study of the newly-discovered differentially-expressed gene helps find out new radiosensitizational targets of elemene. (authors)