宮戸 秀世

This study explores a novel therapeutic approach for peritoneal metastasis (PM) using AAV-mediated delivery of tumor suppressor microRNA-29b (miR-29b) to peritoneal mesothelial cells (PMC). AAV serotypes 2 and DJ demonstrate high transduction efficiency for human and murine PMC, respectively. In vitro analysis indicates that AAV vectors encoding miR-29b precursor successfully elevate miR-29b expression in PMC and their secreted small extracellular vesicle (sEV), thereby inhibiting mesothelial mesenchymal transition and reducing subsequent attachment of tumor cells. A single intraperitoneal (IP) administration of AAV-DJ-miR-29b demonstrates robust and sustained transgene expression, suppressing peritoneal fibrosis and inhibiting the development of PM from gastric and pancreatic cancers. Additionally, AAV-DJ-miR-29b enhances the efficacy of IP chemotherapy using paclitaxel, restraining the growth of established PM. While conventional gene therapy for cancer encounters challenges targeting tumor cells directly but delivering miRNA to the tumor stroma offers a straightforward and efficient means of altering the microenvironment, leading to substantial inhibition of tumor growth. AAV-mediated miR-29b delivery to peritoneum via IP route presents a simple, minimally invasive, and promising therapeutic strategy for refractory PM.

Despite advances in systemic chemotherapy, patients with gastric cancer (GC) and peritoneal metastases (PMs) continue to have poor prognoses. Intraperitoneal (IP) administration of Paclitaxel (PTX) combined with systemic chemotherapy shows promise in treating PMs from GC. However, methods of drug administration need to be optimized to maximize efficacy. In this study, we utilized a mouse model with PMs derived from a human GC cell line, administering PTX either IP or intravenously (IV), and Carboplatin (CBDCA) IV 0, 1, and 4 days after PTX administration. The PMs were resected 30 min later, and concentrations of PTX and CBDCA in resected tumors were measured using liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results indicated that PTX concentrations were higher with IP administration than with IV administration, with significant differences observed on days 0 and 1. CBDCA concentrations 4 days post-IP PTX administration were higher than with simultaneous IV PTX administration. These findings suggest that IP PTX administration enhances CBDCA concentration in peritoneal tumors. Therefore, sequential IV administration of anti-cancer drugs appears more effective than simultaneous administration with IP PTX, a strategy that may improve prognoses for patients with PMs.

Abstract The vagus nerve is the only pathway for transmitting parasympathetic signals between the brain and thoracoabdominal organs, thereby exhibiting anti-inflammatory functions through the cholinergic anti-inflammatory pathway. Despite often being resected during lymph node dissection in upper gastrointestinal cancer surgery, the impact of vagotomy on postoperative outcomes in gastric cancer patients remains unclear. Sub-diaphragmatic vagotomy was performed on C57BL/6 mice. Three weeks later, syngeneic murine gastric cancer cell line YTN16P was injected into the peritoneal cavity, and the number of peritoneal metastases (PM) on the mesentery and omentum compared with control mice. The phenotypes of immune cells in peritoneal lavage and omental milky spots one day after tumor inoculation were analyzed using flow cytometry and immunohistochemistry. Intraperitoneal transfer of 3 × 10⁵ YTN16P significantly increased the number of metastatic nodules on the mesentery in the vagotomy group compared to the control group. The omental metastasis grade was also significantly higher in the vagotomy group. Phenotypic analysis of immune cells in peritoneal lavage did not reveal significant differences after vagotomy. However, vagotomized mice exhibited a notable increase in milky spot area, with a higher presence of cytokeratin(+) tumor cells, F4/80(+) macrophages, and CD3(+) T cells. Vagus nerve signaling appears to regulate the immune response dynamics within milky spots against disseminated tumor cells and inhibits the development of PM. Preserving the vagus nerve may offer advantages in advanced gastric cancer surgery to reduce peritoneal recurrence.

Abstract The spleen is a key source of circulating and tumor-infiltrating immune cells. However, the effect of splenectomy on tumor growth remains unclear. At 3 weeks after splenectomy, we subcutaneously injected LuM1 cells into BALB/c mice and evaluated the growth of primary tumors and lung metastases at 4 weeks after tumor inoculation. In addition, we examined the phenotypes of immune cells in peripheral blood by using flow cytometry and in tumor tissue by using multiplex immunohistochemistry. The growth of primary tumors was reduced in splenectomized mice compared with the sham-operated group. Conversely, splenectomized mice had more lung metastases. Splenectomized mice had fewer CD11b⁺cells, especially monocytic MDSCs (CD11b⁺Gr-1^neg-lowLy6c^high), and NK cells (CD49b⁺CD335⁺). The proportion of NK cells was inversely correlated with the number of lung metastases. In splenectomized mice, the density of CD3⁺ and granzyme B⁺ CD8⁺ T cells was increased, with fewer M2-type macrophages in primary tumors, but NK cells were decreased markedly in lung. Splenectomy concurrently enhances T cell-mediated acquired immunity by reducing the number of monocytic MDSCs and suppresses innate immunity by decreasing the number of NK cells. Splenectomy has opposite effects on primary and metastatic lesions through differential regulation on these two immune systems.

The prognosis of patients with peritoneal metastases from pancreatic cancer is poor, largely due to massive ascites, which precludes systemic treatment. Two patients with a poor performance status and malignant ascites were treated with cell-free and concentrated ascites reinfusion therapy followed by combined chemotherapy with intraperitoneal paclitaxel, intravenous gemcitabine, and nab-paclitaxel. These patients achieved a survival of 19 and 36 weeks with a relatively good quality of life. Combined intraperitoneal paclitaxel and systemic chemotherapy may provide effective palliative management for some patients with peritoneal metastases from pancreatic cancer.

Although miR-29b levels in peritoneal exosomes was markedly reduced in patients with peritoneal metastases(PM), their role has not been fully clarified. Bone marrow derived mesenchymal stem cells(BMSC)were transfected with miR-29b- integrating lentivirus and exosomes isolated from culture supernatants using ultracentrifugation. The effects of the exosomes on human peritoneal mesothelial cells(HPMC)were examined in vitro. The in vivo effect of murine BMSC-derived exosomes was examined with a syngeneic PM model. Culture of HPMC with TGF-β1 decreased expression of E-cadherin and calretinin with increased expression of vimentin, totally restored by adding miR-29b-rich exosomes. The exosomes inhibited proliferation and migration of HPMC, and inhibited adhesion of gastric cancer cells to HPMC. Intraperitoneal(IP)transfer of miR- 29b-rich exosomes every 3 days markedly reduced the number of PM of a murine gastric cancer cell, YTN16P, on the mesentery of C57/BL6 mice. IP administration of miR-29b-containing exosome suppresses the development of PM of gastric cancer.

BACKGROUND: Low-density granulocytes (LDGs) have been shown to be increased in the peripheral blood of patients with inflammatory and malignant diseases. This study evaluated LDGs in patients who underwent radical surgery for colorectal cancer (CRC) and their impact on survival. METHODS: Patients who underwent radical colectomy between 2017 to 2021 were screened for enrolment in the study. Peripheral blood was obtained in the operating room before and after surgery and cells were recovered from the mononuclear layer after density gradient preparations. The ratio of CD66b(+) LDG to CD45(+) leukocytes was determined with flow cytometry, and the association of the ratios with patient outcomes was examined. The main outcome of interest was recurrence-free survival (RFS). RESULTS: Out of 228 patients treated, 176 were enrolled, including 108 colonic and 68 rectal cancers. Overall, 38 patients were stage I, 30 were stage II, 72 were stage 3, and 36 were stage IV. The number of LDGs was markedly increased immediately after surgery and the proportion of LDGs correlated positively with operating time (r = 0.2806, P < 0.001) and intraoperative blood loss (r = 0.1838, P = 0.014). Purified LDGs produced high amounts of neutrophil extracellular traps after short-term culture and efficiently trapped tumour cells in vitro. The proportion of postoperative LDGs was significantly higher in 13 patients who developed recurrence (median 9 (range 1.63-47.0)) per cent versus median 2.93 ((range 0.035-59.45) per cent, P = 0.013). When cut-off values were set at 4.9 per cent, a higher proportion of LDGs was strongly and independently associated with decreased RFS (P = 0.005). In patients with stage III disease, adjuvant chemotherapy significantly improved RFS of patients with high ratios of LDGs, but not low LDGs. CONCLUSION: LDGs are recruited to circulating blood by surgical stress early in the postoperative interval after colectomy for colonic cancer and their postoperative proportion is correlated with recurrence.

AIM: The clinical efficacy of chemoradiotherapy (CRT) is largely dependent on host immune status. The aim of this study was to identify possible markers expressed on circulating mononuclear cells to predict tumour response in patients with locally advanced rectal cancer (LARC). METHODS: Peripheral blood samples were obtained from 47 patients diagnosed with LARC before and after CRT. The numbers of lymphocytes and monocyte subsets were analysed using flow cytometry. Based on clinical and pathological findings, patients were classified as high or low responders. RESULTS: Lymphocyte counts were markedly decreased after CRT. Total numbers of lymphocytes (p = 0.030) and CD4(+) T cells (p = 0.041) in post-CRT samples were significantly lower in low responders than in high responders. In contrast, monocyte counts were not reduced and the number of CD14dim (+) CD16(+) nonclassical (patrolling) monocytes were somewhat increased after CRT (p = 0.050). Moreover, the ratios of programmed cell death ligand 1 (PD-L1) (+) cells on patrolling monocytes before and after CRT were significantly higher in low responders than in high responders (p = 0.0046, p = 0.0006). The same trend was observed for classical and intermediate monocytes. The expression of PD-L1 on patrolling monocytes before CRT correlated inversely with the number of T cells and natural killer (NK) cells after CRT. PD-L1(+) ratio in patrolling monocytes was an independent predictor for response to CRT. CONCLUSION: Programmed cell death ligand 1 (PD-L1) expression on patrolling monocytes suppresses cell-mediated immunity in patients receiving CRT which could be related to tumour response, and may be a useful biomarker for decision-making in the management of patients with LARC.

PURPOSE: Although neutrophil extracellular traps (NETs) are present in various tumors, their roles in tumor biology have not been clarified yet. In this study, we examined how NETs affect the pharmacokinetics and effects of doxorubicin (DOX). METHODS: NETs were generated by neutrophils stimulated with phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS). DOX was added to NETs and their distribution was observed under fluorescein microscopy, and the diffusion of DOX through 3 μM pores from lower to upper chambers was evaluated with a fluorescence-based assay. Ovarian cancer cells, KOC-2S and SKOV3, were embedded in collagen gel droplets and cultured in 3D way and their apoptosis was examined with flow cytometry. RESULTS: DOX was mostly co-localized with NETs. The transfer of DOX to upper chambers increased over time, which was significantly decreased by the presence of neutrophils stimulated with PMA or LPS in the lower chamber. DOX outside of the gel increased the rates of annexin V (+) apoptotic cells, which were significantly reduced by the addition of LPS-stimulated neutrophils in media both in KOC-2S and SKOV3. The reduced diffusion and apoptosis were mostly restored by the destruction of the NETs structure with 1000 u/ml DNAse I. CONCLUSION: NETs efficiently trap and inhibit the diffusion of DOX which may attenuate its ability to induce apoptosis of ovarian cancer cells. Degradation of NETs with DNAse I may augment the response of ovarian cancer to DOX.

Abstract Although preoperative chemoradiation therapy can down-stage locally advanced rectal cancer (LARC), it has little effect on distant metastases. Metformin exerts an anti-cancer effect partly through the activation of host immunity. LuM1, a highly lung metastatic subclone of colon 26, was injected subcutaneously (sc) in BALB/c mice and treated with metformin and/or local radiation (RT). Lung metastases and the primary tumors were evaluated and the phenotypes of immune cells in the spleen and lung metastases were examined with flow cytometry and immunohistochemistry. Local RT, but not metformin, partially delayed the growth of sc tumor which was augmented with metformin. Lung metastases were unchanged in metformin or RT alone, but significantly reduced in the combined therapy. The ratios of splenic T cells tended to be low in the RT group, which were increased by the addition of metformin. IFN-γ production of the splenic CD4(+) and CD8(+) T cells was enhanced and CD49b (+) CD335(+) activated NK cells was increased after combined treatment group. Density of NK cells infiltrating in lung metastases was increased after combination treatment. Metformin effectively enhances local and abscopal effects of RT though the activation of cell-mediated immunity and might be clinically useful for LARC.

Peritoneal dissemination is a major metastatic pathway for gastrointestinal and ovarian malignancies. The miR-29b family is downregulated in peritoneal fluids in patients with peritoneal metastases (PM). We examined the effect of miR-29b on mesothelial cells (MC) which play critical a role in the development of PM through mesothelial-mesenchymal transition (MMT). Human peritoneal mesothelial cells (HPMCs) were isolated from surgically resected omental tissue and MMT induced by stimulation with 10 ng/ml TGF-β1. MiR-29b mimics and negative control miR were transfected by lipofection using RNAiMAX and the effects on the MMT evaluated in vitro. HPMC produced substantial amounts of miR-29b which was markedly inhibited by TGF-β1. TGF-β1 stimulation of HPMC induced morphological changes with decreased expression of E-cadherin and calretinin, and increased expression of vimentin and fibronectin. TGF-β1 also enhanced proliferation and migration of HPMC as well as adhesion of tumor cells in a fibronectin dependent manner. However, all events were strongly abrogated by simultaneous transfection of miR-29b. MiR-29b inhibits TGF-β1 induced MMT and replacement of miR-29b in the peritoneal cavity might be effective to prevent development of PM partly through the effects on MC.

Background: The peritoneal cavity contains many site-specific immune cells which constitute a unique immune microenvironment. However, it is unclear how the local immune signature is altered in patients with peritoneal metastases (PM). Methods: Peritoneal lavage fluid or ascites were obtained from 122 patients with various stages of gastric cancer (GC). Cells recovered from peritoneal fluids were immunostained with mAbs for lymphocyte-, macrophage- and tumor cell-specific antigens and the frequencies of leukocyte subsets and antigen expression levels were evaluated with multi-color flowcytometry. Results: The proportions of CD8(+) T cells, CD3(+)CD56(+) NKT-like cells, and CD3(-)CD56(+) NK cells to CD45(+) leukocytes were significantly reduced in patients with PM compared to those without PM. In patients with PM, the rates of CD8 (+) T cells and NKT-like cells correlated inversely with the tumor leukocyte ratio (TLR), the relative frequency of CD326(+) tumor cells to CD45(+) leukocytes. In contrast, the proportion of CD19(+) B cells was significantly increased in patients with PM, and their proportion correlated positively with the TLR and peritoneal carcinomatosis index (PCI) score. In patients with PM, CD14(+) macrophages tended to be increased with enhanced expression of CD14, CD16 and a M2-macrophage marker, CD163. In particular, macrophages in patients with high TLR contained many granules with high side scatter and CD14 expression in their flow profile compared to those without PM. Conclusion: PM are accompanied by a drastic change in phenotypes of lymphocyte and macrophage in the peritoneal cavity, which might be involved in the development and progression of intraperitoneal tumor growth.

膵全摘では周術期血糖・栄養管理が重要である.12年間の膵全摘32例の周術期血糖・栄養状態を検討した.一期的・二期的膵全摘は各々16例で計48病変の約80%を膵管内乳頭粘液性腫瘍と浸潤性膵管癌が占めた.5年生存率は60.2%,一期的・二期的膵全摘で差はなかった.HbA1cは術前6.7%,術後1年は7.7%と上昇,prognostic nutritional index(PNI)は術前47.8,術後1年は43.0と低下した.予後因子を単変量解析すると術後1年neutrophil-lymphocyte ratio,術前platelet-lymphocyte ratio,術後1年PNIが抽出され,多変量解析では術後1年PNIが有意な因子であった.術後1年PNI 40.5未満は予後不良で,高力価パンクレアチン製剤投与群は予後良好であった.膵全摘後は正しい病態把握のもとに内外分泌治療を行うことが重要である.(著者抄録)

Aim: PD-1/PD-L1 blockade therapy is now widely used for the treatment of advanced malignancies. Although PD-L1 is known to be expressed by various host cells as well as tumor cells, the role of PD-L1 on non-malignant cells and its clinical significance is unknown. We evaluated cell type-specific expression of PD-L1 in colorectal cancer (CRC) specimens using multicolor flow cytometry. Methods: Single cell suspensions were made from 21 surgically resected CRC specimens, and immunostained with various mAbs conjugated with different fluorescent dyes. Tumor cells, stromal cells, and immune cells were identified as CD326(+), CD90(+) and CD45(+) phenotype, respectively. CD11b(+) myeloid cells, CD19(+) B cells and CD4(+) or CD8(+) T cells were also stained in different samples, and their frequencies in the total cell population and the ratio of PD-L1(+) cells to each phenotype were determined. Results: PD-L1 was expressed by all the cell types. The ratio of PD-L1(+) cells to CD326(+) tumor cells was 19.1% ± 14.0%, lower than those for CD90(+) stromal cells (39.6% ± 16.0%) and CD11b(+) myeloid cells (31.9% ± 14.3%). The ratio of PD-L1(+) cells in tumor cells correlated strongly with the ratio in stromal cells, while only weakly with that in myeloid cells. Tumor cells were divided into two populations by CD326 expression levels, and the PD-L1 positive ratios were inversely correlated with the rate of CD326 highly expressing cells as well as mean fluorescein intensity of CD326 in tumor cells, while positively correlated with the frequencies of stromal cells or myeloid cells in CRC. Conclusion: PD-L1 is differentially expressed on various cell types in CRC. PD-L1 on tumor cells may be upregulated together with CD326 downregulation in the process of epithelial mesenchymal transition. Quantification of cell type-specific expression of PD-L1 using multicolor flow cytometry may provide useful information for the immunotherapy of solid tumors.

<title>Abstract</title><sec> <title>Background</title> Intraperitoneal (IP) administration of paclitaxel (PTX) has a great pharmacokinetic advantage to control peritoneal lesions and can be combined with various systemic chemotherapies. In this study, we evaluate the efficacy and tolerability of a combination of IP-PTX and systemic S-1/oxaliplatin (SOX) for induction chemotherapy for patients with peritoneal metastases (PM) from gastric cancer (GC). </sec><sec> <title>Patients and Methods</title> Patients with GC who were diagnosed as macroscopic PM (P1) or positive peritoneal cytology (CY1) by staging laparoscopy between 2016 and 2019 were enrolled. PTX was IP administered at 40 mg/m² on days 1 and 8. Oxaliplatin was IV administered at 100 mg/m² on day 1, and S-1 was administered at 80 mg/m²/day for 14 consecutive days, repeated every 21 days. Survival time and toxicities were retrospectively explored. </sec><sec> <title>Results</title> Forty-four patients received SOX + IP-PTX with a median (range) of 16 (1–48) courses, although oxaliplatin was suspended due to the hematotoxicity or intolerable peripheral neuropathy in many patients. The 1-year overall survival (OS) rate was 79.5% (95% CI 64.4–88.8%) with median survival time of 25.8 months. Gastrectomy was performed in 20 (45%) patients who showed macroscopic shrinkage of PM with a 1-year OS rate of 100% (95% CI 69.5–100%). Grade 2 and 3 histological responses was achieved in four (20%) and one (5%) patients. Grade 3/4 toxicities included neutropenia (11%), leukopenia (39%), and anemia (14%). There were no treatment-related deaths. </sec><sec> <title>Conclusions</title> Combination chemotherapy using SOX + IP-PTX regimen is highly effective and recommended as induction chemotherapy for patients with PM from GC. </sec>

BACKGROUND: Repeat intraperitoneal (IP) chemotherapy has been successfully used for treatment of peritoneal metastases (PM) from gastric cancer (GC). Exosomes play important roles not only in tumor progression but also in chemoresistance via transfer of microRNAs (miRNAs). However, there is little evidence of an effect of miRNAs in peritoneal exosomes on chemosensitivity of peritoneal lesions. METHODS: In 74 patients with advanced GC who underwent staging laparoscopy, exosomes were isolated from peritoneal fluid and expression levels of miR-21-5p, miR-223-3p, and miR-29b-3p determined using TaqMan Advanced miRNA assays. In 43 patients with PM treated with combination chemotherapy, S-1 plus Oxaliplatin together with IP Paclitaxel, the relationship between their relative expression levels and outcomes was examined. RESULTS: The ratios of miR-21-5p/miR-29b-3p and miR-223-3p/miR-29b-3p were significantly upregulated in patients with PM, especially in patients with high serum CA125 levels. They showed a mild association with Peritoneal Cancer Index (PCI) score and ascites. More impressively, the ratios were significantly higher in 16 patients with progression of PM within 1 year compared with 27 patients with an excellent tumor response (miR-21-5p/miR-29b-3p: median 17.49, range 1.83-50.90 vs. median 4.64, range 0.40-38.96, p = 0.0015, miR-223-3p/miR-29b-3p: median 1.02, range 0.23-25.85 vs. median 0.21, range 0.01-50.07, p = 0.0006). Overall survival of patients with high miR-21/miR-29b or miR-223/miR-29b ratios was significantly worse than in patients with low ratios (p = 0.0117, p = 0.0021). CONCLUSIONS: The ratios of miRNAs in peritoneal exosome correlate with survival of the patients with PM from GC and suggest the possibility that they modify the chemosensitivity against IP chemotherapy.

Aim: Peritoneal metastases (PM) frequently occur in patients with gastric cancer and result in a poor prognosis. Exosomes play pivotal roles in tumor metastasis through the transfer of microRNAs (miRNAs). We examined the exosomal miRNA profile in peritoneal fluids to identify novel biomarkers to reflect tumor burden in the peritoneum. Methods: Exosomes were isolated from peritoneal fluids of patients of gastric cancer with macroscopic (P1) or microscopic (P0CY1) peritoneal metastasis (PM) and comprehensive miRNA expression analysis was carried out. Expressions of candidate miRNAs were then validated in all 58 samples using TaqMan Advanced miRNA Assays. Results: In initial screening, we carried out comprehensive analysis of exosomal miRNA using peritoneal fluids from 11 and 14 patients with or without PM, respectively, and identified 11 dysregulated miRNAs in PM (+) samples. Validation analysis showed that four miRNAs (miR-21-5p, miR-92a-3p, miR-223-3p, and miR-342-3p) were significantly upregulated in 12 PM (+) samples, and their expression levels showed positive correlation with peritoneal cancer index. In contrast, miR-29 family were all downregulated in patients with PM (+) samples. Moreover, in 24 patients with pT4 tumor, miR-29 at gastrectomy tended to be lower in six patients with peritoneal recurrence with significant differences in miR-29b-3p (P = .012). Conclusion: Expression pattern of miRNAs in peritoneal exosomes well reflects the tumor burden in the peritoneal cavity and could be a useful biomarker in the treatment of PM.

Many types of immune cells appear in peritoneal cavity after abdominal surgery. In patients who underwent laparotomy due to gastric cancer, peritoneal lavages were obtained before and after surgical procedure. Cells were recovered from intermediate layer after Ficoll-Hypaque centrifugation and analyzed for phenotypes and functions, especially focused on low density neutrophils (LDN). The number of CD66b (+) LDN with mature phenotype was markedly elevated in postoperative as compared with preoperative lavages. Short term culture of the purified LDN produced many threadlike structures positive for SYTOX, nucleic acid staining, as well as histone and myeloperoxidase, suggesting the NETs formation. Human gastric cancer cells, MKN45, OCUM-1 and NUGC-4, were selectively attached on the NETs, which was totally abolished by the pretreatment of DNAse I. Intraperitoneal (IP) co-transfer of the LDN with MKN45 in nude mice strongly augments the metastasis formation on peritoneum, which was strongly suppressed by the following IP administration of DNAse I. Many NETs-like structures were detected on the surface of human omental tissue resected by gastrectomy. NETs on peritoneal surface can assist the clustering and growth of free tumor cells disseminated in abdomen. Disruption of the NETs by DNAse might be useful to prevent the peritoneal recurrence after abdominal surgery.

Malignant tumors are often associated with denervation, suggesting the functional implication of axonal guidance molecules in tumor growth. Here, we assessed the role of semaphorin 3C (sema3C) in the progression of gastric cancer. Immunohistochemistry of human samples revealed that sema3C was strongly expressed in neoplastic cells, especially at the invasion front. Stable transfection of target sequences of sema3C miRNA did not affect the in vitro proliferative activity of human gastric cancer AZ-521 cells. However, when the tumor growth was examined in vivo using an orthotopic model in nude mice, primary stomach tumors as well as metastatic liver tumors were significantly suppressed by sema3C silencing with the reduction of microvessel density. Immunostaining of primary tumor indicated the rate of Ki-67 positive carcinoma cells was decreased, whereas that of apoptotic cells was significantly increased in sema3C-silenced tumor. In addition, capillary-like tubular formation was reduced by the addition of culture media of sema3C miRNA cells compared with the media of control miRNA cells. Semaphorin 3C is positively expressed in gastric cancer cells and may be involved in tumor progression, presumably through the stimulation of angiogenesis. (Cancer Sci 2012; 103: 1961-1966)

Background/Aims: Although preservation of the vaguas nerve is recommended in surgery for early-stage gastric cancer, the physiological effect of vagotomy on the postoperative course has not been well documented. We assessed the effect of vagotomy on the change in fat volume after gastrectomy. Methodology: Subcutaneous fat area (SFA) and visceral fat area (VFA) were separately measured in computed tomographic images taken before and more than 6 months after surgery, using Fat Scan software. The ratios of postoperative/preoperative values of these two fat areas as well as body weight were calculated in 45 patients who underwent DG with (n=24) or without (n=21) vagotomy. Results: Vagotomy did not affect the change in body weight (91.3 +/- 1.7% vs. 92.1 +/- 1.7%). In patients with vagotomy, VFA was reduced to 59.0 +/- 5.1%, which was significantly greater than the reduction in SFA (74.3 +/- 8.7%, p=0.042). In contrast, the reduction ratios of VFA and SFA were equal in vagus nerve-preserved patients (78.4 +/- 6.7% vs. 78.2 +/- 6.9%, p=0.97). Conclusions: The vagus nerve may have a function to locally regulate the intra-abdominal fat volume and preservation of the vagus nerve results in the maintenance of visceral fat after DG.

Background. Body weight loss is a well-known complication after gastrectomy, and is mainly due to reduced fat volume. The effect of vagotomy on the postoperative fat volume was investigated in patients with early stage gastric cancer who underwent gastrectomy. Methods. Subcutaneous fat area (SFA) and visceral fat area (VFA) were separately measured in a computed tomographic (CT) image at the level of the umbilicus using Fat Scan software. The changes in these two fat areas were determined by comparing CT images taken before and more than 6 mo after gastrectomy, and the ratio of postoperative to preoperative fat area was calculated in 77 patients. Results. VFA was reduced significantly greater after total gastrectomy (TG) than distal gastrectomy (DG) (P = 0.0003). In 63 patients who underwent DG, the reduction in VFA, but not in SFA, was significantly less in vagus nerve-preserved than in vagus nerve-nonpreserved cases (59.0% +/- 24.2% versus 74.9% +/- 28.2%, P = 0.027). If compared in each case, VFA showed a significantly greater decrease than did SFA in vagus-nonpreserving, but not in vagus-preserving, gastrectomy (68.2% +/- 37.0% versus 52.7% +/- 25.2%, P &lt; 0.0001; 76.3% +/- 30.0% versus 74.9% +/- 28.2%, P = 0.79). Conclusions. The vagus nerve has a function to locally regulate the amount of intra-abdominal fat tissue, and selective vagotomy in gastrectomy results in a preferential reduction of visceral fat in gastrectomy. Surgical denervation of vagus may be reconsidered as a reasonable treatment for excessive obesity. (C) 2012 Published by Elsevier Inc.

The role and clinical significance of the alteration of sympathetic nerve fibers (SNF) was assessed in gastric cancer. Loss of nerve fibers in malignant tumors has previously been described; however, how dysfunction of the nervous system is involved in cancer progression has not been clarified in clinical studies. The distribution of SNF was examined in 82 surgically resected gastric cancer specimens with immunohistochemical staining of tyrosine hydroxylase (TH), and the association with clinicopathological findings as well as the clinical outcome of the patients was retrospectively evaluated. Arterioles in the normal gastric wall were totally covered with SNF, while the immunoreactivity to TH was markedly reduced around arterioles in cancer tissue. The degree of loss of SNF was significantly correlated with the depth of invasion (P &lt; .0001) and lymph node metastasis (P &lt; .0001) as well as microvessel density (MVD) (P = .0043). Moreover, patients who had tumors with marked loss of SNF showed a markedly worse clinical outcome, with an independent association by multivariate analysis. Loss of periarteriolar SNF is associated with aggressive phenotype of gastric cancer possibly through enhanced angiogenesis and thus could be a useful marker to predict the clinical outcome.

Background Adiponectin has been shown to have suppressive effects on tumor development, but the expression of adiponectin receptors in tumor tissue has not been fully elucidated. The purpose of this study was to quantitatively evaluate the expression of two adiponectin receptors, AdipoR1 and AdipoR2, in gastric cancer tissue. Methods The mRNA levels of AdipoR1 and AdipoR2 were evaluated by quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical staining in 67 gastric cancer tissues and their normal counterparts. In addition, the effects of cytokines on AdipoR1 and AdipoR2 expression in cultured gastric cancer cells were examined. Results As compared to findings in the normal counterparts, AdipoR1 mRNA expression, standardized by beta-actin mRNA, tended to be lower (cancer 0.488 +/- 0.039, normal 0.955 +/- 0.281, p = 0.0726) and AdipoR2 expression was significantly lower (0.818 +/- 0.081, 1.500 +/- 0.222, p = 0.0035) in gastric cancer tissue. Immunohistochemical examination showed the same tendency for AdipoR1 and AdipoR2 expression in epithelial cells. Moreover, AdipoR2 was strongly expressed in interstitial cells. However, the expression levels of these receptors did not show a strong correlation with various pathological factors. An in vitro experiment using two gastric cancer cell lines, MKN-74 and NUGC-3, showed that the expression levels of AdipoR1 and AdipoR2 were significantly decreased by transforming growth factor (TGF)-beta in a dose-dependent manner. Conclusions Two major adiponectin receptors were decreased in gastric cancer as compared to findings in normal gastric epithelium. TGF-beta may be involved in this receptor downregulation. This downregulation may be an ideal strategy for cancer cells to escape the antiproliferative effects of adiponectin in the initial phase of tumor development.

Patients and methods: Gastric cancer patients with peritoneal dissemination and/or cancer cells on peritoneal cytology were enrolled. PTX was administered i.v. at 50 mg/m(2) and i.p. at 20 mg/m(2) on days 1 and 8. S-1 was administered at 80 mg/m(2)/day for 14 consecutive days, followed by 7 days rest. The primary end point was the 1-year overall survival (OS) rate. Secondary end points were the response rate, efficacy against malignant ascites and safety. Results: Forty patients were enrolled, including 21 with primary tumors with peritoneal dissemination, 13 with peritoneal recurrence and six with positive peritoneal cytology only. The median number of courses was 7 (range 1-23). The 1-year OS rate was 78% (95% confidence interval 65% to 90%). The overall response rate was 56% in 18 patients with target lesions. Malignant ascites disappeared or decreased in 13 of 21 (62%) patients. The frequent grade 3/4 toxic effects included neutropenia (38%), leukopenia (18%) and anemia (10%). Conclusion: Combination chemotherapy of i.v. and i.p. PTX with S-1 is well tolerated and active in gastric cancer patients with peritoneal metastasis.

Malignant ascites caused by gastric cancer are chemotherapy resistant and carry a poor prognosis. The efficacy of a regimen including intraperitoneal paclitaxel (PTX) was evaluated in 33 gastric cancer patients with ascetic fluid in the peritoneal cavity diagnosed with computed tomography (CT) scanning. Synchronous administration of intravenous (50 mg/m(2)) and intraperitoneal (20 mg/m(2)) PTX was performed via a subcutaneously placed intraperitoneal catheter on days 1 and 8, and S-1 was administered twice daily at 80 mg/m(2) /day for 14 consecutive days from day 1 to day 14, followed by 7 days of rest. The ascitic fluid volume was calculated with NIH Image J software using continuous CT images. After 2-4 treatment cycles, 23 (70%) patients showed reductions in their ascitic volumes of &gt; 50%. Ascites disappeared completely in 8 patients and were markedly reduced (to &lt;3% of the original volume) in 4 of the 9 patients (44%) who initially had massive (&gt;2,500 ml) ascites. Median overall survival was significantly better in patients with ascitic reduction. Weekly intravenous and intraperitoneal PTX combined with S-1 was highly effective in gastric cancer with malignant ascites. The change in ascitic fluid volumes determined by CT image measurements is a useful predictor of outcome in these patients. Copyright (C) 2010 S. Karger AG, Basel