Microarray analysis of gene expression in lung cancer cell lines treated by fractionated irradiation.

BACKGROUND To identify differentially expressed genes between parent and radioresistant lung cancer cell lines established by fractionated irradiation. MATERIALS AND METHODS Lung cancer cell lines (A549, NCI-H1650) were irradiated with several fractionation schemes. Clonogenic assays were used to identify radioresistant cell lines. We compared the gene expression profiles on a cDNA microarray. RESULTS Four established cell (A549-2G, A549-5G, H1650-2G and H1650-5G) were shown to be radioresistant (p≤0.05). Seventy-two genes were commonly altered in A549-G and 655 genes in H1650-G, compared to their parental cells. Genes in the wingless-type MMTV integration site family (WNT) signaling pathway were the ones most frequently altered in both A549-G and H1650-G cells. Those involved in inflammation; integrin, platelet-derived growth factor (PDGF), interleukin, transforming growth factor-beta (TGFB), epidermal growth factor receptor (EGFR) signaling, were commonly altered in radioresistant H1650 sublines. CONCLUSION The major gene expression changes during irradiation are related to WNT signaling pathway.