聚合酶β在肝癌细胞DNA辐射损伤修复中的作用

THE ROLES OF DNA POLYMERASE β IN HEPATOMA CELLS DNA REPAIR SYNTHESIS AFTER γ-RAY IRRADIATION

利用第二军医大学裸鼠移植性肝癌细胞（ＳＭＭＣ－ＬＴＮＭ）和不同的ＤＮＡ聚合酶选择性抑制剂ＮＥＭ与ｄ２ＴＴＰ，探讨了肿瘤细胞核中ＤＮＡ聚合酶Ｂ参与γ射线辐射损伤ＤＮＡ修复的作用特点。结果表明，该酶参与真核细胞｝射线辐照损伤的ＤＮＡ修复合成，是一种重要的ＤＮＡ修复酶；与正常肝细胞相比，ＳＭＭＣ－ＬＴＮＭ肝癌细胞ＤＮＡ聚合酶β的ＤＮＡ修复合成反应速度快，修复能力强。提示某些肿瘤细胞中该酶的ＤＮＡ辐射损伤修复合成功能比正常细胞的大。

The roles and characteristics of DNA polymerase β of hepatomacells in participating in DNA repair synthesis induced by 6oCo y-rays irradiationwere studied. Transplanted SMMC-LTNM hepatoma in mice was used as a tumor cells model. NEM and d,TTP were used as selective inhibitors to DNA polymerasea and β respectively. It was showed that the polymerase β could take Part in repairsynthesis of DNA damaged by V-rays. The increment of AH-TTP incorporation intoDNA of SMMC-LTNM hepatoma cells nuclei was higher than that of normal hepetocyte nuclei (P<0.01). The DNA repair synthesis induced by DNA POlymerase Preacted more fast in hepatoma cells nuclei than in hepatocytes nuclei too. Theseresults indicated that the DNA repair synthesis of polymerase β in some tumor cellsmight be stronger than normal cells.