Shinya Morimoto

Distinct roles of Rab3B and Rab13 in the polarized transport of apical, basolateral, and tight junctional membrane proteins to the plasma membrane.

Regulated transport of proteins to distinct plasma membrane domains is essential for the establishment and maintenance of cell polarity in all eukaryotic cells. The Rab family small G proteins play a crucial role in determining the specificity of vesicular transport pathways. Rab3B and Rab13 localize to tight junction in polarized epithelial cells and cytoplasmic vesicular structures in non-polarized fibroblasts, but their functions are poorly understood. Here we examined their roles in regulating the cell-surface transport of apical p75 neurotrophin receptor (p75NTR), basolateral low-density lipoprotein receptor (LDLR), and tight junctional Claudin-1 using transport assay in non-polarized fibroblasts. Overexpression of Rab3B mutants inhibited the cell-surface transport of LDLR, but not p75NTR and Claudin-1. In contrast, overexpression of Rab13 mutants impaired the transport of Claudin-1, but not LDLR and p75NTR. These results suggest that Rab3B and Rab13 direct the cell-surface transport of LDLR and Claudin-1, respectively, and may contribute to epithelial polarization.

Expression of histone deacetylase 1 and metastasis-associated protein 1 as prognostic factors in colon cancer

Histone deacetylase 1 (HDAC1) and metastasis-associated protein 1 (MTA1) form the nucleosome remodeling and histone deacetylation (NuRD) complex and may possibly play a central role in cancer development. However, limited data has been reported regarding the expression of both HDAC1 and MTA1. The aim of the present study was to clarify the clinical role of HDAC1 and MTA1 expression in colon cancer. Seventy-four patients with colon cancer, who underwent colectomy at our institution, were enrolled in this study. Expression of HDAC1 and MTA1 was examined immunohistochemically. The patients were divided into four groups: HDAC1-positive group (n=58), HDAC1-negative group (n=16), MTA1-positive group (n=38) and MTA1-negative group (n=36). Clinicopathological factors and survival rates were compared between the groups. Regarding the clinicopathological factors, the depth of tumor invasion and stage correlated significantly with HDAC1 expression (p<0.05). Age, depth of tumor invasion and vascular invasion tended to correlate with MTA1 expression. The 5-year survival rate in the HDAC1-positive group (55.1%) was significantly worse compared to the HDAC1-negative group (86.5%) (p<0.05), and the 5-year survival rate of the MTA1-positive group (50.5%) was significantly worse than that of the MTA1-negative group (73.1%) (p=0.05). In patients with stages II-IV and curability A, B, the survival rate in those with HDAC1-positive expression was significantly worse than those with HDAC1-negative expression (p<0.05), and the survival rate of the MTA1-positive group tended to be worse than that of the MTA1-negative group (p=0.07). Overall survival in both the HDAC1 and MTA1-positive groups was significantly worse than overall survival of the other groups (p<0.05). Disease-free survival in both the HDAC1- and MTA1-positive groups, among patients with stages II-IV and curability A, B, was also significantly worse than that of the other groups (p<0.05). HDAC1 and MTA1 expression levels were significantly related to poorer prognosis. Therefore, HDAC1 and MTA1 expression levels are potential prognostic indicators for colon cancer.

Short-term results of laparoscopic surgery after preoperative chemoradiation for clinically staged T3 and T4 rectal cancer

The feasibility of laparoscopic surgery for clinically staged T3 and T4 rectal cancer has not been clearly defined specifically in cases following preoperative chemoradiation therapy (CRT). Our aim was to investigate the feasibility of laparoscopic surgery after preoperative CRT for clinically staged T3 and T4 rectal cancer.

Preoperative radiotherapy combined with S-1 for advanced lower rectal cancer: phase I trial.

BACKGROUND/AIMS S-1 based chemoradiation is the recommended treatment for rectal cancer; however, the optimal scheduling and dosing are not yet established. A Phase I study was conducted to determine the maximum tolerated dose (MTD) of S-1 with radiotherapy (RT). Endpoints were the toxicity profile of this regimen and to determine the recommended dose (RD). METHODOLOGY Conformal RT was given using 4 fields at daily fractions of 2Gy on 5 days per week to a total dose of 40Gy. Concurrently S-1 was given twice daily throughout RT. Eligible patients had a newly diagnosed clinical stage T3-4 N0-2 M0 rectal adenocarcinoma located within 12cm of the anal verge suitable for curative resection. Surgery was performed 6 weeks from completion of preoperative chemoradiotherapy. The dose escalating from S-1 80mg/m2/day (Level 1) to 100mg/m2/day (Level 2). RESULTS Nine patients were valid for safety. In all patients, S-1 was administered. There was no dose-limiting toxicity (DLT) in patients treated at dose Level 1. Six patients were enrolled in the dose-escalation phase. At dose Level 2, two patients developed DLT and this was considered the MTD. Objective response according to RECIST were observed in 5 of 9 patients who had measurable disease (56%). CONCLUSIONS The RD of S-1 with concurrent RT was determined to be 80mg/m2/day. Preoperative RT combined with S-1 was feasible and well tolerated.

The Effect of Polysaccharide K with S-1 Based Chemotherapy in Advanced Gastric Cancer

BACKGROUND/AIMS Polysaccharide K (PSK) is widely used in Japan as a biological response modifier for cancer patients. We investigated the effects of PSK with S-1 based chemotherapy for advanced gastric cancer patients in immune response. METHODOLOGY Nine advanced gastric cancer patients who underwent chemotherapy at the University of Tokushima were included in this study. In all patients, 3g PSK was received orally and S-1 based chemotherapy for 2 weeks alternately for 8 weeks. Serial changes in immunological parameters (Foxp3, Natural killer (NK), CD4/CD8) were monitored. RESULTS The levels of Foxp3 at 8 weeks was significantly decreased compared with 2 weeks (4.26% vs. 3.11%). In NK activity at 8 weeks was significantly increased compared with 2 weeks (27% vs. 47%). CONCLUSIONS These results of this study suggested that chemotherapy with PSK improved the immune response in advanced gastric cancer patients. Especially Foxp3 was concerned in this mechanism.

Evaluation of relation of RAD51 and the effect of chemo-radiation therapy for advanced rectal cancer.

BACKGROUND/AIMS Chemo-radiation therapy (CRT) has been used to improve local control and survival in patients with advanced rectal carcinoma. However, a significant proportion of patients shows poor response to adjuvant CRT. We thus investigated the usefulness of RAD51 expressions as a predictive maker of the CRT response. METHODOLOGY Forty two patients who suffered from lower rectal cancer were investigated. All patients received preoperative CRT consisting of TS-1, concurrent with 40Gy of pelvic irradiation before having curative radical resection. The relationship between pathological responses of the tumors after therapy and expression of RAD51 was evaluated by immunostaining of resected specimen. RESULTS Positive expression of RAD51 was observed in 24 of 42 patients (57.1%). RAD51 positively expressed in 68.2% (15 of 22 cases) of SD and 42.2% (9 of 20 cases) of PR and CR. There is a tendency of reverse correlation between clinical response and expression of RAD51. Regarding the correlation between pathological response and RAD51 expression, positive expression of RAD51 was recognized in 75.0% (15 of 20 cases) of Grade 1, 47.1% (8 of 17 cases) of Grade 2 and 20.0% (1 of 5 cases) of Grade 3. A significant reverse correlation was recognized between RAD51 expression and pathological responses. CONCLUSIONS RAD51 expression could be one of the most important predictive factors of preoperative CRT for advanced lower rectal cancer.

Impact of education with authorized technical experts on colorectal laparoscopic skills.

BACKGROUND/AIMS Laparoscopic skills training is becoming the standard for educating surgical residents. Because of the specific procedure which differs from that of open surgery, it is imperative to establish a unique training system to promote efficiency of learning laparoscopic skills. The aim of this study was to evaluate the efficiency of learning laparoscopic skills with or without authorized experts of JSES. METHODOLOGY Among 71 patients who underwent laparoscopic colectomy from 2004 to 2009, 30 patients who underwent operation in introduction era without a technical expert (2004-2006), 17 patients who underwent operation in late period of introduction era without a technical expert (2006-2008), 12 patients who underwent operation by resident with technical expert (2008-2009) and 12 patients who underwent operation by technical expert, were investigated. Operative time, amount of blood loss, intra- and post-operative complications and conversion to open surgery were investigated. RESULTS Operative time: 477:333:262:220 minutes (early period:late period:resident:expert), amount of blood loss: 494:73:21:20mL and complications: ileus: 0:1:0:0, leakage: 1:1:3:0, neurological disturbance: 2:1:0:0. CONCLUSIONS Instruction by authorized technical experts of JSES is helpful to avoid pitfalls which are not seen in open surgery without an expert.

The role of UGT1A1 polymorphisms (*28 and *6) in Japanese cancer patients.

570 Background: Combination protocol using FU-LV with irinotecan (FOLFIRI) is currently regarded as standard first-line therapy in advanced colorectal cancer (CRC). Although irinotecan prolongs survival, it causes severe diarrhea and neutropenia. Recent pharmacogenetic studies on irinotecan have revealed significant associations of UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms *28 and *6, the latter being specifically detected in East Asians resulting in severe toxicity. It is necessary that the dose-finding trial that decided the optimal dose according to the gene polymorphism to draw out the maximum therapeutic effect while evading the side effect. Here we present the result of prospective trial of the safety about FOLFIRI therapy according to each gene type of UGT1A1 for Japanese patients with advanced CRC. METHODS From 2008, 250 Japanese patients in TOKUSHIMA University were enrolled in this study. Homo group (*6/*6 and *28/*28 or a both hetero types), hetero group (It was *28 and either *6 was hetero type), and wild group (*28 and *6 were wild types) were defined. On the 23 patients with advanced CRC treated with FOLFIRI after standard chemotherapy, wild and homo groups were administered 150mg/m2 irinotecan, and homo group was 100mg/m2. RESULTS On the 23 patients, the genotypes of UGT1A1 *28 were homozygous in 1 (0.5%) and heterozygous in 5 (28%), *6 were homozygous in 0 and heterozygous in 6 (26%). In *6 heterozygous patients, severe toxicities (grade 3 or more) were found (33%), but in *28 heterozygous patients were not (0%). There was no decrease of irinotecan doses in each group. In Japanese people, UGT1A1 *6 polymorphisms were higher than *28 (*6 homo 3%, hetero 27% vs *28 homo 0.5%, hetero 13%). CONCLUSIONS When the dosage of irinotecan is decided, it is necessary to consider the UGT1A1 *6 heterozygous in Japanese cancer patients. [Table: see text].