HIGH SPECIFIC INDUCTION OF SPERMIDINE SPERMINE N-1-ACETYLTRANSFERASE IN A HUMAN LARGE CELL LUNG-CARCINOMA
HIGH SPECIFIC INDUCTION OF SPERMIDINE SPERMINE N-1-ACETYLTRANSFERASE IN A HUMAN LARGE CELL LUNG-CARCINOMA
复制标题
DOI：
10.1042/bj2700615
复制
发表时间：
1990-09-15
影响因子：
4.1
通讯作者：
PEGG, AE
中科院分区：
文献类型：
--
作者：
CASERO, RA;CELANO, P;PEGG, AE
人大细胞肺癌细胞系 NCI H157 对暴露于多胺类似物 N1 N12-双（乙基）精胺 (BESpm) 的细胞毒性反应先于亚精胺/精胺 N1-乙酰转移酶 (SSAT) 的极高诱导。这种人类酶现已纯化超过 300 倍，具有明显的同质性，并且发现可与针对大鼠肝脏 SSAT 的抗血清发生交叉反应。尽管其他乙酰酶能够使用乙酰辅酶A作为乙酰基供体乙酰化多胺，但发现24小时内超过600倍的诱导是特异性SSAT的，因为基本上所有活性都可以由特异性抗血清沉淀。人酶在还原条件下的亚基大小（约 20 kDa）、底物特异性和动力学参数方面似乎与大鼠酶相似。使用放线菌素 D 和放线菌酮的初步结果表明，N1 N12-双（乙基）精胺对人肺癌细胞系的异常高诱导作用是由新的 mRNA 和蛋白质合成造成的。通过比较对照细胞和处理细胞的 Poly(A) mRNA 的“体外”翻译实验，进一步证实了这一假设。大细胞肺癌细胞系 NCI H157 代表了一个有用的系统，可产生大量 SSAT 蛋白并研究负责诱导和控制这种重要多胺代谢酶的分子事件。通过使用这种丰富的 SSAT 蛋白来源，通过内切蛋白酶 Lys-C 消化片段的 N 端测序确定了部分氨基酸序列。此外，该系统应可用于确定 NCI H157 细胞中异常高的乙酰化酶诱导与观察到的细胞毒性之间是否存在关联。
The cytotoxic response of the human large cell lung carcinoma line NCI H157 to exposure to the polyamine analogue N1 N12-bis(ethyl)spermine (BESpm) is preceded by an extremely high induction of spermidine/spermine N1-acetyltransferase (SSAT). The human enzyme has now been purified greater than 300-fold to apparent homogeneity and found to cross-react with antisera raised against rat liver SSAT. Although other acetylases are capable of acetylating polyamines using acetyl-CoA as the acetyl donor, the greater than 600-fold induction within 24 h was found to be specifically SSAT, since essentially all activity was precipitable by the specific antisera. The human enzyme appears to be similar to the rat enzyme in subunit size under reducing conditions (approximately 20 kDa), substrate specificity and kinetic parameters. Preliminary results using actinomycin D and cycloheximide suggested that the unusually high induction by N1 N12-bis(ethyl)spermine in the human lung cancer line result from new mRNA and protein synthesis. This hypothesis is further substantiated here by ‘in vitro’ translation experiments comparing poly(A) mRNA from control and treated cells. The large cell lung carcinoma line NCI H157 represents a useful system to produce large amounts of the SSAT protein and to study the molecular events responsible for the induction and control of this important polyamine-metabolic enzyme. By using this rich source of SSAT protein, a partial amino acid sequence was determined by N-terminal sequencing of endoproteinase Lys-C digestion fragments. Further, this system should be useful in determining whether there is an association between the unusually high induction of the acetylase and the observed cytotoxicity in the NCI H157 cells.