The present study clearly revealed that EIPL-IPC therapy significantly improved the 5-year survival span of advanced gastric cancer patients with CY+/P-. Thus, EIPL-IPC therapy is strongly recommended as a standard prophylactic strategy for peritoneal dissemination.

PurposeWe designed a phase I/II trial of intraperitoneal (IP) docetaxel plus S-1 to determine the maximum tolerated dose (MTD) and recommended dose (RD) and to evaluate its efficacy and safety in gastric cancer patients with peritoneal carcinomatosis (PC).MethodsPatients with PC confirmed by laparoscopy or laparotomy received IP docetaxel on days 1 and 15 and S-1 (80 mg/m2) on days 1–14 every 4 weeks.ResultsIn the phase I part (n = 12), each cohort received escalating doses of docetaxel (35–50 mg/m2); the MTD was determined to be 50 mg/m2 and the RD was determined to be 45 mg/m2. Dose-limiting toxicities included grade 3 febrile neutropenia and grade 3 diarrhea. In the phase II part (n = 27), the median number of courses was 4 (range 2–11). The 1-year overall survival (OS) rate was 70 % (95 % confidence interval 53–87 %). The overall response rate was 22 % and peritoneal cytology turned negative in 18 of 22 (81 %) patients. The most frequent grade 3/4 toxicities included anorexia (19 %), neutropenia (7 %), and leukopenia (7 %).ConclusionIP docetaxel plus S-1 is active and safety in gastric cancer patients with PC.

Peritoneal dissemination is the most frequent metastatic pattern of scirrhous gastric cancer. However, despite extensive research effort, disease outcomes have not improved sufficiently. Tumor progression and metastasis result from interactions between cancer and various cells in the stroma, including endothelial cells, immune cells and fibroblasts. Fibroblasts have been particularly well studied; they are known to change into carcinoma-associated fibroblasts (CAFs) and produce transforming growth factor β (TGF-β), which mediates cancer-stroma interactions. Here, we investigated whether TGF-β derived from cancer cells in the peritoneal microenvironment activates human peritoneal mesothelial cells (HPMCs), leading to the progression and fibrosis of gastric cancer. We found that activated HPMCs (a-HPMCs) took on a spindle shape formation, decreased the expression of E-cadherin and increased that of α-SMA. Furthermore, a-HPMCs became more invasive and upregulated proliferation of human gastric cancer-derived MKN45 cells following direct cell-cell contact. Notably, MKN45 cells co-cultured with a-HPMCs also acquired anchorage-independent cell growth and decreased expression of E-cadherin in vitro. To measure the effects of the co-culture in vivo, we developed a mouse xenograft model into which different culture products were subcutaneously injected. The largest tumors were observed in mice that had been given MKN45 cells co-cultured with a-HPMCs. Furthermore, these tumors contained HPMC-derived fibrous tissue. Thus, the epithelial-mesenchymal transition (EMT) of HPMCs appears to drive peritoneal dissemination and tumor fibrosis.

While statin intake has been proven to reduce the risk of colorectal cancer (CRC), the mechanism of antitumor effects and clinical significance in survival benefits remain unclear. Statin-induced antiproliferative effects and its underlying mechanism were examined using six CRC cell lines. Statins except pravastatin showed antiproliferative effects (simvastatin ≥ fluvastatin > atorvastatin) even though both of simvastatin and pravastatin could activate mevalonate pathways, suggesting the statin-mediated antiproliferative effects depended on non-mevalonate pathway. Indeed, statin induced p27KIP1 expression by downregulation of histone methyltransferase enhancer of zeste homolog 2 (EZH2), which acts as an epigenetic gene silencer. Additionally, the use of simvastatin plus classII histone deacetylase (HDAC) inhibitor (MC1568) induced further overexpression of p27KIP1 by inhibiting HDAC5 induction originated from downregulated EZH2 in CRC cells and synergistically led to considerable antiproliferative effects. In the clinical setting, Statin intake (except pravastatin) displayed the downregulated EZH2 expression and inversely upregulated p27KIP1 expression in the resected CRC by immunohistochemical staining and resulted in the significantly better prognoses both in overall survival (p = 0.02) and disease free survival (p < 0.01) compared to patients without statin intake. Statins may inhibit tumor progression via an EZH2-mediated epigenetic alteration, which results in survival benefits after resected CRC. Furthermore, statin plus classII HDAC inhibitor could be a novel anticancer therapy by their synergistic effects in CRC.

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Abstract. Angiotensin II is a main effector peptide in renin-angiotensin system, acting as a growth promoter via angiotensin II type 1 (AT1) receptor. The present study examined intrinsic angiotensin II generating system in gastric cancer and potential roles of angiotensin II in cellular proliferation and survival. The expression of AT1 receptor was examined in gastric cancer cell lines and tissues. In addition, we measured angiotensin II concentration in tissues from twenty gastric cancer and corresponding normal region using the florisil method. In vitro, we investigated the potential roles of angiotensin II in cellular proliferation and cell survival in cultured human gastric cancer cell line. The effects of AT1 receptor blocker candesartan were evaluated in a mouse model of peritoneal carcinomatosis. AT1 receptor protein was expressed in gastric cancer cell lines and tissues. Angiotensin II concentration in tumor region (1447±624 pg/g wet) was significantly higher than those of normal region (775±320 pg/g wet) (p<0.05). Angiotensin II stimulates the cell proliferation in the AT1 receptor-positive OCUM2MD3 gastric cancer cell line and this proliferative effect of angiotensin II was inhibited by a specific AT1 receptor antagonist, candesartan. We also confirmed the angiotensin II stimulated ERK1/2, nuclear transcript factor-κB (NF-κB) and surviving activation, which are central molecules of cellular proliferation and survival in OCUM2MD3 cells. Candesartan significantly prolonged survival time in a mouse model of peritoneal carcinomatosis compared with control group (p=0.0.197, log-rank test). Our data provide in vivo evidence of intrinsic angiotensin II generating system in gastric cancer and indicate locally formed angiotensin II is involved in cellular proliferation and survival.

This study evaluated the feasibility and pharmacology of intraperitoneal docetaxel (IP docetaxel) when administered weekly for 3 consecutive weeks, followed by 1 week without treatment. A total of 24 patients with peritoneal carcinomatosis of gastric cancer (10 preoperative, 7 postoperative and 7 recurrent) were enrolled in this study. Docetaxel was dissolved in an isotonic saline to a final 1 liter solution and was administered in a 1 h dosage of 25, 35, 45 and 60 mg/m 2 to determine the maximum tolerated dose (MTD). To measure the docetaxel concentration, blood and peritoneal fluid samples were collected 0.5, 1, 2, 3, 6 and 24 h after administering the drug to 15 patients. A total of 109 chemotherapy cycles were administered, with a median of four cycles per patient (range 2-9). The MTD of the weekly IP docetaxel was defined at 60 mg/m 2. At a docetaxel dosage of 60 mg/m 2 per week, the dose-limiting events of grade 3 abdominal pain and grade 3 diarrhea, which may be associated with local toxicity, occurred. Peak concentrations of peritoneal fluid ranged from 24.5 to 68.7 μg/ml. The mean ratio of the area under concentration (AUC) in the peritoneal fluid to the plasma concentration was 515. Furthermore, the mean of plasma AUC by IP docetaxel was 5.63 μg•h/ml versus that of IV docetaxel at a dose of 60 mg/m 2. The response rate of the preoperative IP docetaxel was 80% (4 CR, 4 PR, 1 NC and 1 PD), which was judged with laparoscopy and peritoneal lavage cytology. Gastrectomy, with D2 lymph node dissection, was performed on all of the patients evaluated as CR. The weekly IP docetaxel demonstrated a low toxicity and high efficacy for peritoneal carcinomatosis with dual anti-cancer effects via the peritoneal surface and capillary blood supply due to its unique pharmacokinetic property.

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