Effect of Everolimus on Radiosensitivity of Human Non_small Cell Lung Cancer Cell Line A549 / 医药导报

ABSTRACT

Objective To exPlore the effect of mammalian target of raPamycin ( mTOR ) inhibitor eVerolimus on radiosensitiVity of human non_small cell lung cancer cell line in vitro by using eVerolimus to inhibit mTOR signaling Pathway of A549. Methods Human non_small cell lung cancer cell line A549 was subjected to radiation alone or in combination with eVerolimus treatment. The 50%inhibition concentration ( IC50 ) of eVerolimus in A549 cells was detected by methylthiazol tetrazolium ( MTT) assay in vitro. EVerolimus at the 20%inhibition concentration ( IC20 ) was used to Pretreat A549 cells for 24 h. Cells were then irradiated by X_ray with 2,4,6,8 Gy. The cell surViVal fraction was comPuted by clone formation. Cell surViVal curVe was fitted by multitarget one_hit model, and mean lethal dose ( D0 ), dose quasithreshold ( Dq ), surViVal fraction at 2 Gy ( SF2 ), and sensitization enhancement ratio (SER) were calculated. The exPression ofγ_H2AX was determined by Western blotting and then the relatiVe gray Values were analyzed. Results EVerolimus significantly imProVed the sensitiVity of A549 cells to radiation. The D0 , Dq and SF2 of eVerolimus+irradiation grouP were significantly lower than those of irradiation grouP. The SER was 1. 36. The residual amount of γ_H2AX Protein in the eVerolimus + irradiation grouP was significantly higher than that of the irradiation grouP. Conclusion EVerolimus inhibiting mTOR signaling Pathway can increase the radiosensitiVity of A549 cells.