摘要
采用杂交，测序，ＲＴ－ＰＣＲ等方法对环磷酰胺（ＣＰ）转化的不同叙利亚地鼠胚胎（ＳＨＥ）细胞株癌基因和抑癌基因进行了分析，结果表明，ｃ－ｍｙｃ癌基因以扩增的方式被激活，在Ｈａ－ｒａｓ和Ｋｉ－ｒａｓ癌基因上均存在着突变．在对Ｈａ－ｒａｓ２０７ｂｐ的一段ｃＤＮＡ序列分析中发现，总共发生了３５处碱基对的替换，除两处是在密码子的第一位碱基外，其余均发生于第三位碱基上，但除第６７位密码子的第三位碱基由于Ｇ－Ｔ颠换导致所编码的甲硫氨酸被异亮氨酸取代外，其余碱基的替换均未导致氨基酸的改变．分析还表明，ＣＰ致Ｈａ－ｒａｓ癌基因的突变无位点专一性．结果还表明，ｐ５３抑癌基因也发生了突变，并且可能属于点突变性质．因此，ＣＰ引起的ＳＨＥ细胞恶性转化的分子机理可能是以点突变和基因扩增的方式引起ｃ－ｍｙｃ，Ｋｉ－ｒａｓ。
In previous study, the malignant transformation of Syrian hamster embryo(SHE) cell induced by cyclophosphamde(CP), following the formation of fibroblast sarcoma, had been identified. In this study, the molecular characters of the transformation were investigated by molecular hybridization, DNA sequencing and RTPCR. The study indicated that not only cmyc oncogene was activated by amplification, but also both Haras and Kiras oncogene had been mutated.The mutation of Haras oncogene fragment(207 bp) had been identified. The results showed that a 35 base substitution occurred. Most of the substitution appeared in the 3rd position of codon, only 2 in the 1st position. But only the GT transvertion of 3 rd base of codon 67 caused methionine to be substituted by isoleucine. Other base replacement did not alter the coded amino acid. The results also showed that there was no site specificity in Haras mutation. The mutation of p53 tumor suppressor gene had also been identified. The results show that the mutation may belong to point mutation. Therefore, the activation of cmyc, Haras, Kiras oncogene and inactivation or other changes of p53 tumor suppressor gene by mutation, along with their cooperation, may be the molecular mechanism of the malignant transformation of SHE cell induced by CP.
出处
《中国药理学与毒理学杂志》
CAS
CSCD
北大核心
1998年第3期196-200,共5页
Chinese Journal of Pharmacology and Toxicology
关键词
环磷酰胺
胚胎细胞
恶性转化
分子生物学
抗癌药
cyclophosphamide
Syrian hamster embryo
oncogenes
genes
suppressor
tumor
mutation
gene amplification
