SOD活性与肺癌细胞染色体异常及DNA合成关系的研究

THE RELATIONSHIP BETWEEN SUPROXIDE DISMUTASE ACTIVITY AND KARYOTYPE,ABERRATION OF CHROMOSOME,AND DNA SYNTHESIS IN LUNG CANCER CELLS

用ＳＯＤ及其活性抑制剂分别提高和降低体外培养的Ａ５４９肺癌细胞内的ＳＯＤ活性，以达到改变细胞内自由基浓度的目的，动态地观察了ＳＯＤ活性与肺癌细胞的染色体核型、畸变率、Ｓ期细胞比率和细胞增殖指数变化之间的关系。结果，受ＳＯＤ处理的细胞其Ｓ期细胞比率由第１天的６３．４下降到第５天的３８．０，增殖指数由第１天的０．６６下降到第５天的０．４４；培养后第１６天的细胞染色体畸变率明显减少，染色体的干系范围由对照组的５６～６０条下降到４０～５５条。而受ＳＯＤ活性抑制剂处理的细胞的染色体畸变率明显增高，并表现出一定的毒性变化。结果提示，在细胞生物学水平上，提高细胞内ＳＯＤ活性可以部分地促进人肺癌细胞的某些遗传表型向正常方面转化，而降低ＳＯＤ活性则可增加细胞毒性损害作用。

Superoxide dismutase(SOD) and its inhibitor,diethyldithiocarbamate(DDC),were used to increase and decrease respectively the SOD activity of A549 lung cancer cells in vitro so as to observe the relationship between SOD activity and the karyotype,aberration of chromosome,the ratio of S phase cells and proliferation index(PI).It was found that the cells cultured in the medium with SOD expressed a reduction of the ratio of Sphase cells(from 63.4 on the first day to 38.0 on the fifth day),reduction of PI(from 0.66 to 0.44) and reduction of chromosome aberration and karyotype(from 56-60 in the control group to 40-55 in the SOD group.At the same time,an increase of chromosome aberration and toxic damage was observed in the cells of the DDC group.The result suggests that the increase of SOD activity might partly improve the transformation of genetic characterizations for human lung cancer cells from malignance to nonmalignance,and in case the activity is decreased the toxic damage of the cells might become serious.