食道癌細胞株における5-フルオロウラシルにより誘導されるDNA障害へのリボヌクレオチドリダクターゼM1の関与

5-Fluorouracil (5-FU) is one of the most well established chemotherapeutic agents in the treatment of esophageal cancer. Ribonucleotide reductase M1 (RRM-1) is the rate?limiting enzyme in de novo DNA synthesis, and has been considered to play an important role in the 5-FU metabolic pathway. However, the means by which RRM-1 participates in the anticancer effects of 5-FU and cisplatin (CDDP) have not been well studied. Here, we show that RRM-1 significantly contributes to the induction of DNA damage by 5-FU in esophageal cancer cell lines. An assay of γ-H2AX focus forma-tion, a marker of DNA damage, after 5-FU treatment revealed good correlation with the levels of RRM-1 protein expression. Moreover, the increased sensitivity and RAD51 focus forma-tion induced by the combination treatment of 5-FU and CDDP were significantly repressed by RRM-1 depletion. These results suggest that RRM-1 is involved not only in the induction of DNA damage by 5-FU but also in the synergistic cytotoxic effect in the combination therapy of 5-FU and CDDP.広島大学(Hiroshima University)博士(医学)Philosophy in Medical Sciencedoctora

Leiomyosarcoma of the sigmoid colon with multiple liver metastases and gastric cancer: a case report

BACKGROUND: Leiomyosarcoma (LMS) of the gastrointestinal tract is an extremely rare high-grade neoplasm with poor prognosis. For advanced LMS with distant metastasis, the decision as to the choice of the most appropriate therapeutic strategy, including chemotherapy and surgery, is difficult. Here, we present an unusual case of LMS of the sigmoid colon with liver metastases and gastric cancer. The survival of this patient was prolonged by a combined modality therapy involving chemotherapy and surgery. CASE PRESENTATION: A 66-year-old woman who had been diagnosed with advanced gastric cancer and multiple liver metastases was referred to our hospital. The initial treatment with docetaxel and S-1 considerably reduced both the gastric cancer and liver tumors; consequently we performed surgical resection. Pathological examination revealed that no viable tumor cells remained in the stomach and chemotherapy resulted in complete remission of the gastric cancer. The liver tumors were immunohistochemically diagnosed as LMS. A tumor of the sigmoid colon was subsequently discovered and the liver tumors were found to have recurred. The surgically resected sigmoid colon and liver tumors were all immunohistochemically diagnosed as LMS. These findings indicated that the multiple liver metastases arose from the LMS in the sigmoid colon, and that they were accompanied by advanced gastric cancer. We performed another surgical resection and administered chemotherapy to treat the recurring liver metastases. The patient survived for 4 years and 10 months after initial presentation at our hospital. CONCLUSION: Colonic LMS is rare and its joint occurrence with gastric cancer is extremely unusual. Although LMS is a high-grade neoplasm, a multimodal therapeutic approach can increase patient survival time even when multiple liver metastases are present

Arginine enriched EN after total gastrectomy

The effects of early enteral arginine-rich nutrition (EAN) were analyzed among patients undergoing curative-intent total gastrectomy for gastric cancer. There were 19 patients in this prospective study, all randomly assigned to either a parenteral nutrition (PN) group or an EAN group for the first seven days after surgery. The EAN group received 1.8-fold greater arginine (10.1 g / day) compared with the PN group, which was administered through an enteral tube inserted into the jejunal loop. Both groups were provided almost identical amounts of total amino acids (54 g / day), and the total energy was set at 65% of the total requirement (25 kcal / kg / day). No significant differences were observed between the two groups in postoperative complications, length of hospital stay, oral intake, nutritional status, or body weight. The serum arginine profile was similar in the two groups, as it decreased significantly on postoperative day (POD) 1, and gradually returned to preoperative levels by POD 7. The nitrogen balance remained negative until POD 7 in the PN group, but turned neutral at POD 7 in the EAN group. While we could not confirm body weight loss improvement, these results suggested that early arginine-rich enteral nutrition could improve the nitrogen balance after total gastrectomy