照射后HeLa细胞对CDDP诱导的DNA交联产生抗性

Resistance of HeLa Line Irradiated with 60Co γRay to the Interstrand DNA Crosslink Induced by Diamminedichloroplatinum

应用ＥＢ荧光分析法测定了人宫颈癌上皮细胞系（ＨｅＬａｌｉｎｅ）经单次６０Ｃｏ照射后顺铂（ＣＤＤＰ）诱导的ＤＮＡ链内交联反应（ｃｔ％）．经研究发现，１～６Ｇｙ照射后，细胞相对生长分数（ｆｒａｃｔｉｏｎｏｆｃｏｎｔｒｏｌｇｒｏｗｔｈ，ＦＣＧ）减小，单位细胞ＤＮＡ含量增高，ＨｅＬａ细胞与ＣＤＤＰ的交联反应明显降低，且与照射剂量呈依赖关系．结果提示，γ射线照射后存活的肿瘤细胞可能对ＣＤＤＰ或烷化剂的化学治疗作用产生抗性．

The detection of DNA crosslink induced by diaminedichloroplatinum (CDDP) in HeLa line irradiated with 60Co γray was carried out using ethidium bromide fluorescence assay. The results showed that after single doses (1～6 Gy)of irradiation, the fraction of control growth of HeLa cells declined and the DNA content per unit cell of HeLa line increased, and the formation of interstrand DNA crosslink induced by CDDP reduced apparently with increments of dose of irradiation. The findings suggest that tumor cells surviving γirradiation may become resistant to chemotherapy with alkylating agents such as CDDP.