Systematic analyses of genes associated with radio sensitizing effect by celecoxib,a specific cyclooxygenase-2 inhibitor

To investigate genes regulated by cox-2 or a cox-2 specific inhibitor,celecoxib,in irradiated cancer cells,we analyzed changes in gene expression using complementary dna microarray following celecoxib or combined celecoxib and ionizing radiation (ir) treatment in a stable cox-2 knockdown a549 (as) and a mock cell line (an). thirty-six genes were differentially expressed by cox-2 knockdown. celecoxib changed the expressions of 40 and 69 genes in an and as cells,respectively. twenty-seven genes were synchronously regulated by cox-2 and celecoxib. among these,celecoxib regulated ras homolog gene family b and mitosin protein expression in a cox-2 dependent manner,especially in irradiated cells. in addition,we identified 11 genes that changed by more than 1. 5 times the expected additive values after celecoxib and ir treatment. the current study may provide evidence that cox-2 or celecoxib regulates various intracellular functions in addition to their enzymatic activity regulation. we also identified candidate molecules that may be responsible for cox-2-dependent radiosensitization by celecoxib.