Matsubara N, Hiramatsu M, Edamatsu R, Mizukawa K, Mori A, Orita K
First Department of Surgery, Okayama University Medical School, Japan.
Free Radic Biol Med. 1997;22(4):679-87. doi: 10.1016/s0891-5849(96)00384-x.
Constitutive production of hydroxyl radicals from four established cancer cell lines was detected as spin adducts of 5,5-dimethyl-l-pyroline-N-oxide (DMPO), using an electron spin resonance spectrometer. The generated hydroxyl radicals was decreased in three out of four cancer cell lines when incubated in vitro for 3 h with TNF-alpha No direct scavenging effect of TNF-alpha on hydroxyl radicals or superoxide anions was observed in the in vitro radical generation system. The modulation of intracellular reactive oxygen species of these cancer cells by adding menadione or CuDIPS to the culture medium changed the antiproliferative effect of TNF-alpha on the cells. The ultrastructural localization of the radical-generating sites in cancer cells was visualized using the diaminobenzidine/horseradish peroxide histochemical system at the electron microscopic level. The hydrogen peroxide-dependent formation of electron-dense materials localized at the mitochondrial membranes was decreased after the treatment of the cancer cells with TNF-alpha. These data indicate that the reduction of radical generation in cancer cells by TNF-alpha may be an early mechanism that contributes to the antiproliferative effect of this cytokine on some cancer cells.
使用电子自旋共振光谱仪，检测到来自四种已建立的癌细胞系的羟基自由基的组成性产生，其以5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）的自旋加合物形式存在。当在体外与TNF-α孵育3小时时，四种癌细胞系中有三种所产生的羟基自由基减少。在体外自由基生成系统中未观察到TNF-α对羟基自由基或超氧阴离子有直接清除作用。通过向培养基中添加甲萘醌或铜二异丙基苯磺酸盐来调节这些癌细胞的细胞内活性氧，改变了TNF-α对细胞的抗增殖作用。在电子显微镜水平上，使用二氨基联苯胺/辣根过氧化物酶组织化学系统对癌细胞中自由基产生位点进行超微结构定位。在用TNF-α处理癌细胞后，定位于线粒体膜的电子致密物质的过氧化氢依赖性形成减少。这些数据表明，TNF-α降低癌细胞中自由基的产生可能是该细胞因子对某些癌细胞产生抗增殖作用的早期机制。
