Basnak'ian A G, Bubnov N V, Kirsanova I D, Votrin I I
Eksp Onkol. 1989;11(2):15-9.
The DNA endonuclease (Aendo) and DNA topoisomerase (Atopo) activities in liver nucleus extracts of normal rats, in DENA-induced hepatomas and in liver tissues around tumours were investigated. The profile of nuclear endonucleases measured in the presence of 2 mM CaCl2 + 5 mM MgCl2, or 5 mM MnCl2, or 5 mM MgCl2, or 2 mM CaCl2 (pH 7.4), or I mM EDTA (pH 5.0) was different in normal and tumour tissues. Mn2+-dependent endonuclease was the main endonuclease in the tumour tissue, whereas Ca2+, Mg2+-dependent endonuclease was the main one in the normal liver and in the tissue around the tumour. An increase in the Mn2+-dependent endonuclease activity correlated with a decrease in the hepatoma differentiation level. Atopo of types I and II increased in the tissue around the tumour. Aendo and Atopo of cellular nuclei decreased in animals given DENA without the liver tumour.
对正常大鼠肝细胞核提取物、二乙基亚硝胺（DENA）诱导的肝癌以及肿瘤周围肝组织中的DNA内切酶（Aendo）和DNA拓扑异构酶（Atopo）活性进行了研究。在存在2 mM氯化钙 + 5 mM氯化镁、或5 mM氯化锰、或5 mM氯化镁、或2 mM氯化钙（pH 7.4）、或1 mM乙二胺四乙酸（EDTA，pH 5.0）的情况下所测定的核内切酶图谱，在正常组织和肿瘤组织中有所不同。锰离子依赖性内切酶是肿瘤组织中的主要内切酶，而钙离子、镁离子依赖性内切酶则是正常肝脏和肿瘤周围组织中的主要内切酶。锰离子依赖性内切酶活性的增加与肝癌分化水平的降低相关。I型和II型Atopo在肿瘤周围组织中增加。在未发生肝肿瘤的给予DENA的动物中，细胞核的Aendo和Atopo减少。
