Hideyo Miyato

Phase II study of weekly intravenous and intraperitoneal paclitaxel combined with S-1 for advanced gastric cancer with peritoneal metastasis

BACKGROUND A phase II study to evaluate the efficacy and tolerability of weekly i.v. and i.p. paclitaxel (PTX) combined with S-1 was carried out in gastric cancer patients with peritoneal metastasis. 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.

Adiponectin inhibits the growth and peritoneal metastasis of gastric cancer through its specific membrane receptors AdipoR1 and AdipoR2

Adiponectin, a circulating peptide hormone produced in adipose tissue, has been shown to be reduced in the plasma of patients with cancer, suggesting that this adipokine may be mechanically involved in the pathogenesis of adiposity‐related carcinogenesis. In this study, we examined the expression of adiponectin receptors (AdipoR1 and AdipoR2) and assessed the function of adiponectin in gastric cancer. All of the six gastric cancer cell lines significantly expressed mRNA and protein of both receptors with variable levels. Addition of 30 µg/mL adiponectin potently induced apoptosis and inhibited the proliferation of AZ521 and HCG27. Down‐regulation of either AdipoR1 or AdipoR2 by specific siRNA significantly suppressed the growth inhibitory effects of adiponectin in both cell lines. Moreover, a local injection of adiponectin markedly inhibited the growth of AZ521 inoculated subcutaneously in nude mice. Similarly, the continuous intraperitoneal infusion of adiponectin effectively suppressed the development of peritoneal metastasis of AZ521. Adiponectin negatively regulates the progression of gastric cancer cells possibly through both AdipoR1 and AdipoR2. Although adiponectin was already reported to have antiangiogenic effects, our results suggest that the antitumor effect of adiponectin was, at least partially, dependent on the direct effects on tumor cells. (Cancer Sci 2007; 98: 1120–1127)

Leptin augments proliferation of breast cancer cells via transactivation of HER2.

Excessive fat mass is a risk factor for postmenopausal breast cancer. Leptin, a fat cell-derived peptide hormone, elicits a growth-stimulating effect in breast cancer cells with leptin receptor expression, although the leptin-induced signal in malignant cells is not fully understood. Here, we found that exogenous leptin induced tyrosine phosphorylation of HER2 in SKBR3 cells, which showed marked overexpression of HER2. Phosphorylation of HER2 was detected at 2 min and continued up to 120 min after the start of stimulation. Leptin-induced HER2 phosphorylation was partially reduced by an epidermal growth factor receptor inhibitor, AG1478, or a Janus-activated kinase inhibitor, AG490. Leptin also induced phosphorylation of extracellular signal-regulated kinase 1/2, which was mostly abrogated by a HER2 tyrosine kinase inhibitor, AG825. In a proliferation assay, addition of 500 ng/mL leptin increased the proliferation of SKBR3, which was totally inhibited by AG825. Collectively, our data suggest that leptin can transactivate HER2 through both epidermal growth factor receptor and Janus-activated kinase 2 activation, which can cause the growth of breast cancer cells with HER2 overexpression.

Phase I Pharmacokinetic Study of Weekly Intravenous and Intraperitoneal Paclitaxel Combined with S-1 for Advanced Gastric Cancer

Objectives: A dose-escalation study of weekly intraperitoneal paclitaxel (PTX) combined with S-1 and intravenous PTX was performed to determine the maximum-tolerated dose (MTD) and recommended dose (RD) in gastric cancer patients. Patients and Methods: Nine gastric cancer patients with peritoneal dissemination and/or cancer cells on peritoneal cytology were enrolled. PTX was administered intravenously on days 1 and 8 at a fixed dose of 50 mg/m2, and intraperitoneally with an initial dose of 20 mg/m2, stepped up to 30 or 40 mg/m2. S-1 was administered at a fixed dose of 80 mg/m2/day for 14 consecutive days, followed by 7 days of rest. A pharmacokinetic study of PTX was also performed. Results: The MTD was determined to be 30 mg/m2, as 2 of 3 patients developed dose-limiting toxicities, grade 3 febrile neutropenia and diarrhea. Therefore, the RD was determined to be 20 mg/m2. The intraperitoneal and serum PTX concentration remained effective for over 72 and 48 h, respectively. Conclusions: Combined chemotherapy of S-1 plus weekly intravenous and intraperitoneal PTX was shown to be a safe regimen that should be further explored in clinical trials.

Pharmacological Synergism Between Cannabinoids and Paclitaxel in Gastric Cancer Cell Lines

Orally applicable Delta9-tetrahydrocannabinol and its synthetic derivatives have been used as antiemetic drugs during chemotherapy in cancer patients. However, it is not well known how cannabinoids influence the effects of chemotherapeutic agents on malignant tumors. In this study, we investigated how the endogenous cannabinoid anandamide (AEA) changes the effect of paclitaxel on gastric cancer cell lines. In the human gastric cancer cell line, HGC-27, which express cannabinoid receptor 1 (CB1), AEA stimulated proliferation at concentrations under 1 microM, while it strongly suppressed proliferation through the induction of apoptosis at 10 microM. This bimodal effect was reproduced by a selective CB1 agonist, arachidonyl-2-chloroethylamide, although the effects were less marked. When AEA was used with paclitaxel, AEA at 10 microM synergistically enhanced the cytotoxic effect of paclitaxel, whereas it showed no significant effect at lower concentrations. Flow cytometric analysis revealed that addition of 10 microM AEA synergistically enhanced paclitaxel-induced apoptosis, possibly through the activation of caspase-3, -8, and -9. Our results suggest that cannabinoids could be a good palliative agent for cancer patients receiving paclitaxel.

Semaphorin 3C is involved in the progression of gastric cancer.

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.

Vagus Nerve Preservation Selectively Restores Visceral Fat Volume in Patients with Early Gastric Cancer who Underwent Gastrectomy

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 < 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.

Intra-peritoneal administration of paclitaxel with non-animal stabilized hyaluronic acid as a vehicle--a new strategy against peritoneal dissemination of gastric cancer.

BACKGROUND AND AIM Intra-peritoneal administration (i.p.) of Taxanes has recently been reported to be effective for the treatment of peritoneal dissemination, presumably because extremely high concentration of the drug is achievable onto the disseminated nodules as compared to intra-venous administration. Here, we aimed to investigate the ability of non-animal stabilized hyaluronic acid (NASHA) to retain the anti-cancer drugs in the peritoneal cavity, and, consequently, improve the efficacy of i.p. administration of paclitaxel. METHODS Mice were inoculated i.p. with MKN45P gastric cancer cells. The mice received i.p. administrations of paclitaxel, without or with NASHA, once a week for 3 consecutive weeks, and the intra-peritoneal nodules were counted after 4 weeks. The ability of NASHA to retain the i.p. administered liquid and paclitaxel in abdominal cavity was also investigated. Finally, the concentration of paclitaxel in metastatic nodule was measured with HPLC. RESULTS In the group receiving paclitaxel with NASHA, the number of disseminated nodules were significantly smaller than in those receiving paclitaxel without NASHA. The fluid volumes and concentration of paclitaxel recovered from the abdominal cavity as well as the concentrations of paclitaxel in metastatic nodule were significantly increased by the addition of NASHA. CONCLUSION Our results indicate that NASHA improves the exposure time of i.p. administrated paclitaxel to disseminated nodules by retaining the drug in the abdominal cavity. Since the material is used in cosmetic surgery with few adverse effects, NASHA can be clinically used as the vehicle for the i.p. administration of anti-cancer agents for advanced gastric cancer with peritoneal dissemination.

Weekly intravenous and intraperitoneal paclitaxel combined with S-1 for malignant ascites due to advanced gastric cancer.

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/m2) and intraperitoneal (20 mg/m2) PTX was performed via a subcutaneously placed intraperitoneal catheter on days 1 and 8, and S-1 was administered twice daily at 80 mg/m2/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 >50%. Ascites disappeared completely in 8 patients and were markedly reduced (to <3% of the original volume) in 4 of the 9 patients (44%) who initially had massive (>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.

Neutrophil Extracellular Traps Generated by Low Density Neutrophils Obtained from Peritoneal Lavage Fluid Mediate Tumor Cell Growth and Attachment

Activated neutrophils release neutrophil extracellular traps (NETs), which can capture and destroy microbes. Recent studies suggest that NETs are involved in various disease processes, such as autoimmune disease, thrombosis, and tumor metastases. Here, we show a detailed in vitro technique to detect NET activity during the trapping of free tumor cells, which grow after attachment to NETs. First, we collected low density neutrophils (LDN) from postoperative peritoneal lavage fluid from patients who underwent laparotomies. Short-term culturing of LDN resulted in massive NET formation that was visualized with green fluorescent nuclear and chromosome counterstain. After co-incubation of human gastric cancer cell lines MKN45, OCUM-1, and NUGC-4 with the NETs, many tumor cells were trapped by the NETs. Subsequently, the attachment was completely abrogated by the degradation of NETs with DNase I. Time-lapse video revealed that tumor cells trapped by the NETs did not die but instead grew vigorously in a continuous culture. These methods may be applied to the detection of adhesive interactions between NETs and various types of cells and materials.