Transgenic rats carrying copies of the human c-Ha-ras proto-oncogene exhibit enhanced susceptibility to N-butyl-N-(4-hydroxybutyl)nitrosamine bladder carcinogenesis
Transgenic rats carrying copies of the human c-Ha-ras proto-oncogene exhibit enhanced susceptibility to N-butyl-N-(4-hydroxybutyl)nitrosamine bladder carcinogenesis
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DOI：
10.1093/carcin/21.7.1391
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发表时间：
2000-07-01
期刊：
影响因子：
4.7
通讯作者：
Tsuda, H
中科院分区：
文献类型：
--
作者：
Ota, T;Asamoto, M;Tsuda, H
我们已经建立了一个转基因大鼠系，携带三个拷贝的人c-Ha-ras原癌基因与自己的原始启动子区，Jcl/SD-TgN（HrasGen）128 Ncc（Hras 128）大鼠。在未处理的转基因大鼠膀胱上皮中可以检测到来自转导的和内源性c-Ha-ms基因表达的c-Ha-rns蛋白。（4-羟丁基）-亚硝胺（BBN）诱导的膀胱癌发生，雄性转基因和野生型同窝仔用含0.05%BBN的饮用水处理10周，然后在第20周处死，Hras 128大鼠中每只大鼠的总肉眼膀胱肿瘤（包括移行细胞乳头状瘤和酸性癌（TCC））的数量和体积远大于野生型大鼠。在Hras 128大鼠中，每只大鼠的癌数量也显著更高。在Hras 128大鼠中还观察到两例TCC表现出膀胱肌层的侵袭，这在所用实验条件下的野生型动物中极为罕见。经RFLP分析和直接测序证实，21例膀胱移行细胞癌中仅有2例（9.5%）存在CGC → GAC突变，SSCP分析未发现内源性c-Ha-rns基因突变。25例野生型大鼠膀胱肿瘤中有1例（4.0%）存在内源性c-Ha-ras基因第12位密码子突变（GGA → GAA）。这些结果表明Hras 128大鼠对BBN致癌高度敏感，可作为分析膀胱肿瘤发生的大鼠模型。突变结果表明，增强的肿瘤发展主要不是由于转基因中发生的突变。
We have established a transgenic rat line carrying three copies of the human c-Ha-ras proto-oncogene with its own original promoter region, Jcl/SD-TgN(HrasGen)128Ncc (Hras128) rat. c-Ha-rns protein from expression of transduced and endogenous c-Ha-ms genes could be detected in the bladder epithelium of untreated transgenic rats, To examine their susceptibility to N-butyl-N-(4- hydroxybutyl)-nitrosamine (BBN)-induced urinary bladder carcinogenesis, male transgenic and wild-type littermates were treated with 0.05% BBN in their drinking water for 10 weeks and then killed at week 20, The numbers and volumes of total macroscopic bladder tumors including both transitional cell papillomas acid carcinomas (TCC) per rat were much greater in Hras128 rats than in their wild-type counterparts. The numbers of carcinomas per rat were also significantly greater in Hras128 rats. Two cases of TCC exhibiting invasion of the bladder muscle layer, which is extremely rare in the wild-type animals under the experimental conditions used, were also observed in Hras128 rats. The CGC-->GAC mutations at codon 12 of the transgene were observed in only two TCC out of 21 bladder tumors (9.5%), assessed by RFLP analysis and direct sequencing, SSCP analysis did not show any endogenous c-Ha-rns gene mutations. One of 25 tumors (4.0%) in wild-type rats had an endogenous c-Ha-ras gene mutation at codon 12 that was detected (GGA-->GAA) by single-strand conformation polymorphism and direct sequencing, These results indicate that the Hras128 rat is highly susceptible to BBN carcinogenesis and may be utilized as a rat model for analysis of bladder tumor development. The mutation findings indicate that the enhanced tumor development is not primarily due to mutations occurring in the transgene.