Lee Y J, Hou Z Z, Curetty L, Borrelli M J, Corry P M
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48072.
J Cell Physiol. 1990 Nov;145(2):324-32. doi: 10.1002/jcp.1041450218.
Previous studies suggested that a 26 kDa protein might play an important role in protein synthesis-independent thermotolerance development in CHO cells. To determine if this phenomenon was universal, four mammalian cell lines, viz., CHO, HA-1, murine Swiss 3T3, and human HeLa, were studied. Cells were heated at 42 degrees C, and the level of 26 kDa protein in the nucleus was measured, together with clonogenic survival and protein synthesis. The results demonstrated that 1) the 26-kDa protein was present in the four different cell lines, and 2) the level of the 26 kDa protein in their nuclei was decreased by 30-70% after heating at 42 degrees C for 1 hr. However, restoration of this protein occurred along with development of chronic thermotolerance. The protein synthesis inhibitor cycloheximide (10 micrograms/ml) neither inhibited the development of chronic thermotolerance nor affected the restoration of the 26 kDa protein in the nucleus. In fact, this drug protected cells from hyperthermic killing and heat-induced reduction of 26 kDa protein in the nucleus. Heat sensitizers, quercetin (0.1 mM), 3,3'-dipentyloxacarbocyanine iodide (DiOC5[3]: 5 micrograms/ml), and stepdown heating (45 degrees C-10 min----42 degrees C), potentiated hyperthermic killing and inhibited or delayed the restoration of the 26 kDa protein to the nucleus. These results support a correlated, perhaps causal relationship between the restoration of the 26 kDa protein and chronic thermotolerance development in four different mammalian cell lines.
先前的研究表明，一种26 kDa的蛋白质可能在CHO细胞中不依赖蛋白质合成的耐热性发展过程中发挥重要作用。为了确定这种现象是否具有普遍性，研究了四种哺乳动物细胞系，即CHO、HA-1、小鼠瑞士3T3和人HeLa细胞系。将细胞加热至42℃，并测量细胞核中26 kDa蛋白质的水平，同时检测克隆形成存活率和蛋白质合成情况。结果表明：1）26 kDa蛋白质存在于这四种不同的细胞系中；2）在42℃加热1小时后，它们细胞核中26 kDa蛋白质的水平下降了30%-70%。然而，随着慢性耐热性的发展，这种蛋白质会恢复。蛋白质合成抑制剂环己酰亚胺（10微克/毫升）既不抑制慢性耐热性的发展，也不影响细胞核中26 kDa蛋白质的恢复。事实上，这种药物可保护细胞免受高温杀伤以及热诱导的细胞核中26 kDa蛋白质的减少。热增敏剂槲皮素（0.1毫摩尔）、3,3'-二戊基氧羰花青碘化物（DiOC5[3]：5微克/毫升）以及逐步降温加热（45℃-10分钟----42℃）会增强高温杀伤作用，并抑制或延迟26 kDa蛋白质向细胞核的恢复。这些结果支持了在四种不同的哺乳动物细胞系中，26 kDa蛋白质的恢复与慢性耐热性发展之间存在关联，或许是因果关系。
