Kudo M, Ogura T, Esumi H, Sugimura T
Biochemistry Division, National Cancer Center Research Institute, Tokyo, Japan.
Mol Carcinog. 1991;4(1):36-42. doi: 10.1002/mc.2940040107.
The activation of the c-Ha-ras gene and its carcinogen specificity were examined in squamous cell carcinomas (SCCs) induced by the mutagenic heterocyclic amines 2-amino-3-methylimidazo [4,5-f]quinoline (IQ),2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) in the Zymbal gland in rats. DNA fragments of the c-Ha-ras gene were amplified from formalin-fixed and paraffin-embedded tissues by polymerase chain reaction and analyzed for activating mutations involving codons 12, 13, and 61 by oligonucleotide differential hybridization and sequencing. c-Ha-ras mutations were found in four of seven and two of six Zymbal gland SCCs induced by IQ and MeIQx, respectively. These mutations were located in either codon 13 or 61. In the case of MeIQ, point mutations at the second nucleotide of codon 13 were found in nine of the total 14 Zymbal gland SCCs and in one papilloma. Of the nine SCCs that had mutations in codon 13, two possessed mutations at the second nucleotide of codon 12 as well. Most reported mutations in c-Ha-ras are located at codon 12 or 61, but the heterocyclic amines in this study induced mutations not only at codons 12 and 61 but also in codon 13. Transversions were the dominant mutation induced by these heterocyclic amines.
在大鼠鼓室腺中，研究了诱变杂环胺2-氨基-3-甲基咪唑[4,5-f]喹啉（IQ）、2-氨基-3,8-二甲基咪唑[4,5-f]喹喔啉（MeIQx）和2-氨基-3,4-二甲基咪唑[4,5-f]喹啉（MeIQ）诱导的鳞状细胞癌（SCC）中c-Ha-ras基因的激活及其致癌物特异性。通过聚合酶链反应从福尔马林固定、石蜡包埋的组织中扩增c-Ha-ras基因的DNA片段，并通过寡核苷酸差异杂交和测序分析涉及密码子12、13和61的激活突变。在IQ和MeIQx诱导的7个鼓室腺SCC中的4个以及6个中的2个中发现了c-Ha-ras突变。这些突变位于密码子13或61。在MeIQ的情况下，在总共14个鼓室腺SCC中的9个以及1个乳头状瘤中发现了密码子13第二个核苷酸的点突变。在密码子13发生突变的9个SCC中，有2个在密码子12的第二个核苷酸处也有突变。大多数报道的c-Ha-ras突变位于密码子12或61，但本研究中的杂环胺不仅在密码子12和61处诱导突变，也在密码子13处诱导突变。颠换是这些杂环胺诱导的主要突变类型。
