Enhancement Of Radioresponse By Combining Treatment With The Selective Epidermal Growth Factor Receptor-Tyrosine Inhibitor ZD1839(Iressa)

[ Objective ] To investigate antiproliferative activity of ZD1839, the combining effect of ZD1839 and radiation on the A549 human lung adenocarcinomal cell line and several possible mechanism.[Methods] The antiproliferative activity of ZD1839 was determined by MTT analysis,and the IC50 was caculated.Clonogenic assay was used to investigate the combining effect of ZD1839 and radiation on A549 cell lines.The A549 cell lines were divided into four groups. (1) the control: without ZD1839 and radiation interference; (2) radiation alone: γ-ray radiation at a dose of 2, 4, 6 or 8Gy,respectively; (3) ZD1839 alone: ZD1839(1umol/L) exposed to A549 cell lines for 72h; (4) ZD1839 and radiation: After 1umol/L ZD1839 exposed to A549 cell lines for 2h, γ-ray radiation was given,and then ZD1839 exposed for 72h;Afterγ-ray radiation,A549 cell lines were exposed to ZD1839 1umol/L for 72h.γ-ray radiation were delivered at a dose of 2, 4, 6 or 8Gy, respectively.The combining effect was quantified by calculating the SF(Surviving Fraction).Flow cytometry was used to observe the cell-cycle effect and apoptosis of radiation with ZD1839 on A549 cell lines.[Results] The effect of the dose-dependent growth inhibition was observed by the MTT analysis,and the IC₅₀ was 5.2umol/L.The synergetic...