Seed-specific expression of truncated OsGAD2 produces GABA-enriched rice grains that influence a decrease in blood pressure in spontaneously hypertensive rats

Gamma-aminobutyric acid (GABA) is a four-carbon amino acid that is commonly present in living organisms and functions as a major inhibitory neurotransmitter in mammals. It is understood to have a potentially anti-hypertensive effect in mammals. GABA is synthesized from glutamate by glutamate decarboxylase (GAD). In plants, GAD is regulated via its calmodulin-binding domain (CaMBD) by Ca2+/CaM. We have previously reported that a C-terminal truncated version of one of the five rice GAD isoforms, GAD2ΔC, revealed higher enzymatic activity in vitro and that its over-expression resulted in exceptionally high GABA accumulation (Akama and Takaiwa, J Exp Bot 58:2699–2607, 2007). In this study, GAD2ΔC, under the control of the rice glutelin promoter (GluB-1), was introduced into rice cells via Agrobacterium-mediated transformation to produce transgenic rice lines. Analysis of the free amino acid content of rice grains revealed up to about a 30-fold higher level of GABA than in non-transformed rice grains. There were also very high levels of various free protein amino acids in the seeds. GABA-enriched rice grains were milled to a fine powder for oral administration to spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). Six weeks of administration showed that transgenic rice brings about a 20 mmHg decrease in blood pressure in two different kinds of SHRs, while there was no significant hypotensive effect in WKYs. These results suggest an alternative way to control and/or cure hypertension in humans with GABA-enriched rice as part of a common daily diet

Endobronchial metastasis from adenocarcinoma of gastric cardia 7 years after potentially curable resection

Endobronchial metastasis (EBM) is a rare form of metastasis from extrapulmonary malignant tumors, although there are few reports of EBM from gastric cancer specifically. We report the case of a 51-year-old woman who had undergone gastrectomy for advanced gastric cancer seven years previously but was diagnosed with a solitary lung tumor by follow-up computed tomography. On diagnosis of primary lung cancer, she underwent pulmonary lobectomy, but immunohistochemical examination confirmed the resected tumor to be an EBM from the gastric cancer. Six months later, she was diagnosed with peritoneal metastases and underwent chemotherapy with gastric cancer regimen. She is still alive at 33 mo after the lobectomy. Generally, the prognosis for EBM is poor although multidisciplinary treatment can lead to long-term survival. Precise diagnosis on the basis of detailed pathological and immunohistochemical evaluation can contribute to deciding the most effective treatment and improving prognosis

Identification of colorectal cancer patients with tumors carrying the <it>TP53 </it>mutation on the codon 72 proline allele that benefited most from 5-fluorouracil (5-FU) based postoperative chemotherapy

<p>Abstract</p> <p>Background</p> <p>Although postoperative chemotherapy is widely accepted as the standard modality for Dukes' stage C or earlier stage colorectal cancer (CRC) patients, biomarkers to predict those who may benefit from the therapy have not been identified. Previous <it>in vitro </it>and clinical investigations reported that CRC patients with wild-type p53 gene (<it>TP53)</it>-tumors benefit from 5-fluorouracil (5-FU) based chemotherapy, while those with mutated <it>TP53</it>-tumors do not. However, these studies evaluated the mutation-status of <it>TP53 </it>by immunohistochemistry with or without single-strand conformation polymorphism, and the mutation frequency was different from study to study. In addition, the polymorphic status at p53 codon 72, which results in arginine or proline residues (R72P) and is thought to influence the function of the protein significantly, was not examined.</p> <p>Methods</p> <p>To evaluate the significance of the <it>TP53 </it>mutation as a molecular marker to predict the prognosis of CRC patients, especially those who received postoperative chemotherapy, we examined the mutation by direct sequencing from fresh CRC tumors and evaluated the R72P polymorphism of the mutated <it>TP53 </it>by a combined mutant allele- and polymorphic allele-specific polymerase chain reaction (PCR).</p> <p>Results</p> <p>The <it>TP53 </it>mutation occurred in 147 (70%) of 211 Japanese CRC tumors. The mutation was observed in 93 (63%) tumors on the R72 allele and in 54 (37%) tumors on the P72 allele. Although the alterations to <it>TP53 </it>have no prognostic significance for CRC patients overall, we found that Dukes' stage C CRC patients who did not receive postoperative chemotherapy and carried the mutated <it>TP53</it>-R72 showed significantly longer survival times than those with the mutated <it>TP53</it>-P72 when evaluated by overall survival (<it>p = 0.012</it>).</p> <p>Conclusion</p> <p>Using a combined mutant allele- and polymorphic allele-specific PCR, we defined the codon 72 polymorphic status of the <it>TP53 </it>mutated allele in Japanese CRC patients. We raised a possibility that Dukes' stage C colorectal cancer patients with tumors carrying <it>TP53 </it>mutation, especially the P72 allele, benefited from 5-FU based postoperative chemotherapy.</p