Walker C, Ahn Y T, Everitt J, Yuan X
Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, USA.
Mol Carcinog. 1996 Feb;15(2):154-61. doi: 10.1002/(SICI)1098-2744(199602)15:2<154::AID-MC8>3.0.CO;2-J.
Germline alterations of the human von Hippel-Lindau (VHL) tumor suppressor gene predispose to renal cell carcinoma and a constellation of other tumor types found in VHL disease. This gene is also mutated or deleted in a high proportion of sporadic nonpapillary renal cell carcinomas. In the Eker rat model, spontaneous renal cell carcinoma develops with a high frequency. We therefore investigated the role of this tumor suppressor gene in the development of these hereditary rat tumors. By using reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis, the sequence of the rat VHL gene was determined over the portion of the gene homologous to regions where most mutations in the human VHL gene occur. The sequence homology was 90% and the amino-acid identity 99% between the rat and human genes. A developmental and tumor-specific pattern of expression for the VHL gene was found; a ubiquitous 3.2-kb transcript was expressed in all rat tissues examined (neonatal kidney, lung, liver, brain, heart, kidney, spleen, testis, and stomach), and an additional 4.5-kb transcript was expressed in neonatal kidney and cell lines derived from Eker rat renal cell carcinomas (ERC cell lines). To determine whether mutations in the VHL gene were involved in tumor development in the Eker model, RT-PCR, single-strand conformation polymorphism (SSCP) analysis, and direct sequencing were used to search for alterations in this gene in the ERC cell lines. Alterations in the VHL gene were not detected by SSCP, and these data were confirmed by direct sequencing. Transformed rat kidney epithelial cell lines derived from Fisher rats also expressed the VHL gene but like the ERC cell lines did not contain mutations in the VHL gene. These data indicate that in the rat, transformation of kidney epithelial cells and the development of solid, nonpapillary renal cell carcinoma can occur via pathways that are independent of alterations at the VHL gene locus.
人类VHL（希佩尔-林道）肿瘤抑制基因的种系改变易患肾细胞癌以及VHL病中发现的一系列其他肿瘤类型。在散发性非乳头状肾细胞癌中，该基因也有很高比例发生突变或缺失。在埃克大鼠模型中，自发性肾细胞癌高频发生。因此，我们研究了这种肿瘤抑制基因在这些遗传性大鼠肿瘤发生过程中的作用。通过逆转录酶（RT）-聚合酶链反应（PCR）分析，测定了大鼠VHL基因与人类VHL基因大多数突变发生区域同源部分的序列。大鼠和人类基因之间的序列同源性为90%，氨基酸同一性为99%。发现了VHL基因的发育和肿瘤特异性表达模式；在所有检测的大鼠组织（新生肾、肺、肝、脑、心、肾、脾、睾丸和胃）中均表达一种普遍存在的3.2kb转录本，另外在新生肾和源自埃克大鼠肾细胞癌的细胞系（ERC细胞系）中表达一种4.5kb转录本。为了确定VHL基因的突变是否参与埃克模型中的肿瘤发生，使用RT-PCR、单链构象多态性（SSCP）分析和直接测序来寻找ERC细胞系中该基因的改变。通过SSCP未检测到VHL基因的改变，直接测序证实了这些数据。源自费希尔大鼠的转化大鼠肾上皮细胞系也表达VHL基因，但与ERC细胞系一样，VHL基因中没有突变。这些数据表明，在大鼠中，肾上皮细胞的转化和实性、非乳头状肾细胞癌的发生可通过独立于VHL基因座改变的途径发生。
