Relationship Between Expression Of ATM Protein And Radiosensitivity In Lung Cancer Cell Lines

Objective: To invesigate the relationship between radiosensitivity and expression levels of ATM protein in lung cancer cell lines, and maybe as a foundation for our future research and as a new clinic strategy for radiosensitization treatment of lung cancer.Methods: Radiosensitivity of two lung cancer cell lines A549 and NCI-H446 was observed by MTT colorimetric assay and clonogenic survival assay. The localization and expression of ATM protein were analyzed by fluorescence immunohistochemical method and laser scanning confocal microscope(LSCM). Then to find out the relation between expression of ATM protein and different radionsensitivity in two lung cancer cell lines.Results: Two lung cancer cell lines , were given irradiation at 0, 2, 4, 6, 8Gy, respectively. With regard to A549 and NCI-H446, the survival fraction in MTT colorimetric assay were 79.0%, 34.6%, 12.3%, 4.0% and 56.0%, 17.0%, 3.4%, 0.8%. The survival fraction in clonogenic survival assay for A549 and NCI-H446 were 81.0%, 32.4%, 12.0%, 3.5% and 52.4%, 17.0%, 3.2%, 0.7% respectively; then by way of fitting cell survival cure, the parameters of multi-target/single-hit model, D0 was 1.583 and 1.503Gy, and N was 4.914 and 2.433 for A549 and NCI-H446. ATM protein was located in karyon and cytoplasm; The intense fluorescence of ATM protein was stronger in A549 than that in NCI-H446 significantly(P﹤0.0001).Conclusions: Both radionsensitivity and expression of ATM protein were different typically for two lung cancer cell lines as A549 and NCI-H446, might indicate the negative correlation between expression of ATM protein and radiosensitivity.