纳米金对SPC-A1肺癌细胞体外放射增敏作用的研究

目的 研究纳米金联合兆伏级射线对肺腺癌SPC-A1细胞的体外放射增敏作用，并从细胞周期、细胞凋亡角度探讨纳米金的放射增敏机制。方法 选用肺腺癌SPC-A1细胞进行体外培养，采用CCK-8法检测不同浓度纳米金（0、1、0.5、0.25、0.125、0.0625 mmol／L）处理SPC-A1细胞24、48、72 h后的细胞毒性，确定纳米金溶液的实验浓度；经纳米金溶液培养的SPC-A1细胞株分别给予6 MV X线和4 MeV电子线照射0、1、2、4、6、8 Gy后，体外细胞培养克隆法研究纳米金的放射增敏作用，计算存活分数。使用单击多靶模型公式拟合，计算出Dq、D0等放射生物学参数和放射增敏比（SER）；流式细胞仪检测纳米金处理SPC-A1细胞24 h后各组的细胞凋亡和细胞周期的变化。结果 不同浓度纳米金处理不同时间后，对SPC-A1细胞的增殖无明显抑制，确定以纳米金溶液初始浓度（0.25 mmol／L）作为实验浓度。直径25 nm、0.25 mmol／L的纳米金粒子联合6 MV X线和4 MeV 电子线照射SPC-A1细胞的SER分别是1.111和1.214。流式细胞仪检测显示，纳米金不增加细胞的凋亡，但能明显增加射线对细胞的凋亡作用。细胞周期显示纳米金能加速细胞的G0／G1期，使细胞周期阻滞在G2／M期。结论 纳米金联合6 MV X线或4 MeV 电子线对SPC-A1细胞有放射增敏作用，其机制可能与增加射线对细胞的凋亡和细胞周期同步化有关。

The effect of gold nanoparticles on increasing radiosensitivity of SPC-A1 lung cancer cell in vitro

Objective To observe the radiosensitizing effect of gold nanoparticles（AuNPs） on SPC-A1 lung cancer cell line of megavoltage ray radiation therapy and probe its radiosesitizing mechanisms in vitro.Methods SPC-A1 cells were cultured in vitro. The cytotoxicity effect of different concentrations of AuNPs（0， 1， 0.5， 0.25， 0.125，0.0625 mmol／L） on SPC-A1 cells were measured by CCK-8 at 24， 48 and 72 h after treatment. The experimental concentration of AuNPs was determined according to CCK-8 method. SPC-A1 cells were processed with different doses of 6MV X-ray and 4MeV electron beam including 0， 1， 2， 4， 6， 8 Gy alone or together with AuNPs（0.25 mmol／L））. The cell survival faction（SF） was evaluated by using a standard colony forming assay. Cell cycle distribution and apoptosis of different groups were detected at 24 h after treatment with AuNPs（0.25 mmol/L） by flow cytometry assay. Results Cell viability test showed the proliferation of SPC-A1 cells was not significantly inhibited after treatment with different concentrations of AuNPs at different points of time， and had no effect on the time and concentration. The initial concentration of AuNPs（0.25 mmol／L）） was used as the concentration of the experiment. The enhanced radiosensitivity of SPC-A1 lung cancer cells has been observed. The sensitivity enhancement ratio（SER） at 37％ survival level were 1.111 and 1.214 at 24 h after treatment of AuNPs combined with 6MV X ray and 4MeV electron beam repectively. Flow cytometry showed that cell apoptosis was not increased by individual AuNPs， but the rays on cell apoptosis was significantly increased. The cell cycle detection showed that the cell cycle was accelerated at the G0／G1 phase， and arrested at the G2／M phase after the treatment with AuNPs. Conclusion AuNPs can be used for the enhancement of radiation effects on SPC-A1 lung cancer cells of megavoltage X-ray radiation therapy and electron radiation therapy beams. Its mechanism may relate to increase apoptosis and cell cycle synchronization.