Sun Y, Oberley L W, Oberley T D, Elwell J H, Sierra-Rivera E
Radiation Research Laboratory, University of Iowa, Iowa City 52242.
Carcinogenesis. 1993 Jul;14(7):1457-63. doi: 10.1093/carcin/14.7.1457.
Normal embryonal mouse liver cells in culture were shown to undergo spontaneous transformation during prolonged subculture. The spontaneously transformed cells lost their anchorage dependence, as measured by a soft agar assay, and gave rise to tumors in nude mice. Accompanying this transformation, the antioxidant enzymes, copper- and zinc-containing superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), catalase (CAT) and glutathione reductase, decreased significantly in activity; the decline in enzymatic activity of CuZnSOD, MnSOD and CAT was due to a decline in the levels of immunoreactive protein. These spontaneously transformed high passage in vitro liver cells appeared similar in morphology, antioxidant enzyme activity and tumorigenicity to their counterparts transformed by N-methyl-N-nitro-N-nitrosoguanidine and Simian virus 40. These data provide experimental evidence that changes in antioxidant enzymes are associated with spontaneous in vitro cellular transformation of mouse embryonal liver cells.
培养中的正常胚胎小鼠肝细胞在长期传代培养过程中会发生自发转化。通过软琼脂试验测定，自发转化的细胞失去了对贴壁的依赖性，并在裸鼠体内产生肿瘤。伴随着这种转化，抗氧化酶，即含铜和锌的超氧化物歧化酶（CuZnSOD）、锰超氧化物歧化酶（MnSOD）、过氧化氢酶（CAT）和谷胱甘肽还原酶的活性显著降低；CuZnSOD、MnSOD和CAT酶活性的下降是由于免疫反应性蛋白水平的下降。这些体外高代自发转化的肝细胞在形态、抗氧化酶活性和致瘤性方面与其经N-甲基-N-硝基-N-亚硝基胍和猿猴病毒40转化的对应细胞相似。这些数据提供了实验证据，表明抗氧化酶的变化与小鼠胚胎肝细胞的体外自发细胞转化有关。
