Department of Biochemistry, The Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo, Japan.
Odontology. 2012 Jul;100(2):149-55. doi: 10.1007/s10266-011-0032-3. Epub 2011 May 24.
RAS overexpression and its active mutations are involved in malignant tumorigenesis. However, the mutation rates in oral carcinoma cells differ between populations. In the present study, genomic DNA of oral carcinoma cells (HOC313, TSU, HSC2, HSC3, KOSC2, KOSC3, SCCKN, OSC19, Ca9.22, and Ho1u1 cells) or normal gingival fibroblasts (GF12 cells) derived from a Japanese population were amplified by polymerase chain reaction using primer sets, spanning HRAS and KRAS exons. Nucleotide substitutions were analyzed by single strand conformation polymorphism. In contrast to no substitutions in KRAS, nine different substitutions were detected in HRAS. Of the nine, six substitutions were located at intron 1 (HSC2 and HSC3 cells) or intron 2 (HSC3, SCCKN and Ca9.22 cells), and one each of exon 1 (all cells), exon 2 (HOC313, TSU, HSC2 and HSC3 cells) and the 5' upstream region (all cells). Substitutions at exons 1 and 2 did not affect the amino acid sequence; the exon 1 substitution was positioned at the 5' untranslated region, which may be a single nucleotide polymorphism (SNP) sequence because all the cells were isolated from a Japanese population, and the mutations at exon 2 was a silent mutation. A substitution at the 5' upstream region was an SNP. These data demonstrate that SNPs and point mutations observed in HRAS do not change the amino acid sequence, and suggest that the mutations affecting the amino acid sequence may be a rare event in oral carcinomas of the Japanese population.
RAS 过度表达及其活性突变与恶性肿瘤的发生有关。然而，口腔癌细胞中的突变率因人群而异。在本研究中，使用引物组通过聚合酶链反应扩增了源自日本人群的口腔癌细胞（HOC313、TSU、HSC2、HSC3、KOSC2、KOSC3、SCCKN、OSC19、Ca9.22 和 Ho1u1 细胞）或正常牙龈成纤维细胞（GF12 细胞）的基因组 DNA。通过单链构象多态性分析核苷酸取代。与 KRAS 无取代相反，在 HRAS 中检测到九个不同的取代。在这九个中，有六个取代位于内含子 1（HSC2 和 HSC3 细胞）或内含子 2（HSC3、SCCKN 和 Ca9.22 细胞），一个位于外显子 1（所有细胞），一个位于外显子 2（HOC313、TSU、HSC2 和 HSC3 细胞）和 5'上游区（所有细胞）。外显子 1 和 2 的取代不影响氨基酸序列；外显子 1 的取代位于 5'非翻译区，这可能是单核苷酸多态性（SNP）序列，因为所有细胞均来自日本人群，并且外显子 2 的突变是沉默突变。5'上游区的取代是 SNP。这些数据表明，在 HRAS 中观察到的 SNP 和点突变不会改变氨基酸序列，并表明影响氨基酸序列的突变在日本人的口腔癌中可能是罕见事件。
