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Physiological role of neonatal brain-derived carcinostatic factor(NBCF) during the ontogenesis

新生儿脑源性致癌因子（NBCF）在个体发生过程中的生理作用

基本信息

批准号：
62571003
负责人：
MIWA Nobuhiko
金额：
$ 1.73万
依托单位：
Hiroshima Prefectural University (1989)国立予防衛生研究所 (1987-1988)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

The mouse brain, at the neonatal stage but not at the adult or fetal stage, secretes a protein, which inhibits growth and DNA synthesis of malignant cells preferentially over those of normal cells, and so is termed neonatal brain-derived carcino- static factor (NBCF). In the present study NBCF was prepared from conditioned medium of the neonatal brain cultured, and was obtained by HPLC as a homogeneous protein (62 kDa, PI 9.1); physics-chemical and biological properties of NBCF differ from those of cerebral proteins known. A 1,2-cis-diol affinity column retained NBCF, which was thereafter eluted with D-sorbitol; NBCF treated with neuraminidase lost part of activity without emergence of new N-terminal amino acids, suggesting glycan moieties required for the activity exhibition. This is supported by repression of NBCF secretion by tunicamycin of doses as low as is not cytotoxic. NBCF did not hydrolize target proteins; cytotoxic action of NBCF was not counteracted by a diversity of protease inhibitors. An ether-extract of NBCF was not cytotoxic whereas the ether-insoluble residuum retained part of the initial activity. NBCF was inactivated with immobilized trypsin or with dithiothreitol combined with guanidine more markedly than with either agent. Thus cytotoxicity exhibition of NBCF, mediated through actions other than proteolysis, is attributed to the proteinic principle but not to protein-bound lipophilic ligands, and requires retention of the protein conformation and intramolecularly buried SS bonds.

小鼠大脑在新生阶段，而不是在成体或胎儿阶段，会分泌一种蛋白质，这种蛋白质优先抑制肿瘤细胞的生长和DNA合成，因此被称为新生儿脑源性抑癌因子(NBCF)。在本研究中，NBCF是从培养的新生儿脑的条件培养液中制备的，并通过高效液相色谱法获得了一种均一的蛋白质(62 kDa，等电点9.1)，其理化和生物学性质与已知的脑蛋白质不同。1，2-顺式二醇亲和层析柱保留了NBCF，然后用D-山梨醇洗脱；神经氨酸酶处理的NBCF失去了部分活性，没有出现新的N-末端氨基酸，这表明活性展示所需的多糖部分。这一点得到了衣霉素对NBCF分泌的抑制作用的支持，因为低剂量的衣霉素没有细胞毒性。NBCF不能水解靶蛋白；NBCF的细胞毒作用不能被多种酶抑制剂所抵消。NBCF的乙醚提取物没有细胞毒性，而乙醚不溶残渣保留了部分初始活性。用固定化胰酶或二硫苏糖醇与胍联用时，NBCF的失活效果比任何一种方法都明显。因此，NBCF的细胞毒性表现不是通过蛋白水解性的作用，而是基于蛋白质的原理，而不是蛋白质结合的亲脂配体，并且需要保留蛋白质的构象和分子内埋藏的SS键。