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Terumi Taniguchi

Publications and source records attributed to Terumi Taniguchi.

7 recordsLinked to original sources
PubMed2004

Inactivating mutations of the human base excision repair gene NEIL1 in gastric cancer.

Oxidized DNA base lesions, such as thymine glycol (Tg) and 8-hydroxyguanine, are often toxic and mutagenic and have been implicated in carcinogenesis. To clarify whether NEIL1 protein, which exhibits excision repair activity towards such base lesions, is involved in gastric carcinogenesis, we examined 71 primary gastric cancers from Japanese patients and four gastric cancer cell lines for mutations and genetic polymorphisms of the NEIL1 gene. We also examined 20 blood samples from Chinese patients for NEIL1 genetic polymorphisms. Three mutations (c.82_84delGAG:p.Glu28del, c.936G > A and c.1000A > G:p.Arg334Gly) and two genetic polymorphisms were identified. When the excision repair activity towards double-stranded oligonucleotide containing a Tg:A base pair was compared among six types of recombinant NEIL1 proteins, p.Glu28del-type NEIL1, found in a primary case, was found to exhibit an extremely low activity level. Moreover, c.936G > A, located in the last nucleotide of exon 10 and detected in the KATO-III cell line, was shown to be associated with a splicing abnormality using an in vivo splicing assay. An immunofluorescence analysis showed that the wild-type NEIL1 protein, but not the truncated protein encoded by the abnormal transcript arising from the c.936G > A mutation, was localized in the nucleus, suggesting that the truncated protein is unlikely to be capable of repairing nuclear DNA. An expression analysis revealed that NEIL1 mRNA expression was reduced in six of 13 (46%) primary gastric cancer specimens that were examined. These results suggest that low NEIL1 activities arising from mutations and reduced expression may be involved in the pathogenesis in a subset of gastric cancers.

Alternative Splicing↗
PubMed2004

Three-dimensional microarray compared with PCR-single-strand conformation polymorphism analysis/DNA sequencing for mutation analysis of K-ras codons 12 and 13.

BACKGROUND: We developed a rapid, precise, and accurate microarray-based method that uses a three-dimensional platform for detection of mutations. METHODS: We used the PamChip microarray to detect mutations in codons 12 and 13 of K-ras in 15 cell lines and 81 gastric or colorectal cancer tissues. Fluorescein isothiocyanate-labeled PCR products were analyzed with the microarray. We confirmed the microarray results with PCR-single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. RESULTS: We could correctly identify wild-type, heterozygous, and homozygous mutant genotypes with the PamChip microarray in <3.5 h. The array data were consistent with those of PCR-SSCP analysis and DNA sequencing. All 15 cell lines and 80 of 81 clinical cancer specimens (98.8%; 95% confidence interval, 96.4-100%) were genotyped accurately with the microarray, a rate better than that of direct DNA sequencing (38.9%) or SSCP (93.8%). Only one clinical specimen was misdiagnosed as homozygous for the wild-type allele. Densitometric analysis of SSCP bands indicated that the content of the mutant allele in the specimen was approximately 16%. The PamChip microarray could detect mutant alleles representing more than 25% of the SSCP band proportions. Therefore, the limit for detection of mutant alleles by the PamChip microarray was estimated to be 16-25% of the total DNA. CONCLUSIONS: The PamChip microarray is a novel three-dimensional microarray system and can be used to analyze K-ras mutations quickly and accurately. The mutation detection rate was nearly 100% and was similar to that of PCR-SSCP together with sequencing analysis, but the microarray analysis was faster and easier.

Cell Line, Tumor↗
PubMed2003

[Basic studies on mutation analysis of K-ras codon 12 by use of three-dimensional microarray system].

A next-generation DNA microarray system, FD10 has been developed. It is based around the PamChip, a custom-made microarray, which consists of a solid three-dimensional structure that facilitated the incorporation of probe molecules. We applied this microarray system on a detection of K-ras mutation at codon 12 in some cancer cell lines. The PCR products amplified by use of FITC labeled primers were applied onto probe-absorbed microarray. After hybridization, the signal was imaged by CCD camera and analyzed by the exclusive software. We confirmed the microarray results by PCR-SSCP and sequencing analyses. Ten, two and three out of 15 cell lines were homozygous for wild type allele, heterozygous for wild and mutant allele, and homozygous for mutant alleles, respectively. Signals hybridized with antisense probes were stronger than those with sense probes, without PSN1 cell line. The system had a good reproducibility. Essentially, the microarray results were consistent with PCR-SSCP and sequencing results. In conclusion, the FD10 microarray system was easy to operate and short to get results. It might be useful for a focused array applicable for specific purposes. The K-ras mutation detection system worked well and will be applied to clinical specimens soon.

Codon↗