Transcriptional inhibition of feline immunodeficiency virus by alpha-amanitin.

Alpha-amanitin, one of the amatoxins in egg amanita, has a cyclic peptide structure, and was reported as having antiviral activity against several viruses. We investigated whether α-amanitin has antiviral activity against feline immunodeficiency virus (FIV). FL-4 cells persistently infected with FIV Petaluma were cultured with α-amanitin. Reverse transcriptase (RT) activity in the supernatant of FL-4 cells was significantly inhibited by α-amanitin. In addition, the production of FIV core protein in FL-4 cells was inhibited by α-amanitin when analyzed by western blotting. Furthermore, α-amanitin inhibited the transcription of FIV in real-time RT-PCR. These data suggested that α-amanitin showed anti-FIV activity by inhibiting the RNA transcription level.

Photodynamic hyperthermal chemotherapy with indocyanine green in feline vaccine-associated sarcoma.

The anticancer effects of photodynamic hyperthermal chemotherapy (PHCT), which consists of a combination of indocyanine green photodynamic hyperthermal therapy and local chemotherapy, have previously been reported. The present study investigated the effect of PHCT in six cases of feline vaccine-associated sarcoma (FVAS) following conservative surgical resection. No recurrence was observed in three out of six (50%) cases, while recurrence was observed in the remaining three cases. Of note, each feline with recurrences had previously undergone surgical resection more than three times, whereas those without recurrence had undergone no or one previous resection. In addition, the three animals in which there was no recurrence survived between 893 and 1,797 days following surgery. In conclusion, the results of the present study suggested that PHCT may be a candidate as a novel adjuvant cancer therapy for FVAS.

Photodynamic hyperthermal chemotherapy with indocyanine green: a novel cancer therapy for 16 cases of malignant soft tissue sarcoma.

Sixteen cases of malignant soft tissue sarcoma (STS; 10 canines and six felines) were treated with a novel triple therapy that combined photodynamic therapy, hyperthermia using indocyanine green with a broadband light source, and local chemotherapy after surgical tumor resection. This triple therapy was called photodynamic hyperthermal chemotherapy (PHCT). In all cases, the surgical margin was insufficient. In one feline case, PHCT was performed without surgical resection. PHCT was performed over an interval of 1 to 2 weeks and was repeated three to 21 times. No severe side effects, including severe skin burns, necrosis, or skin suture rupture, were observed in any of the animals. No disease recurrence was observed in seven out of 10 (70.0%) dogs and three out of six (50.0%) cats over the follow-up periods ranging from 238 to 1901 days. These results suggest that PHCT decreases the risk of STS recurrence. PHCT should therefore be considered an adjuvant therapy for treating companion animals with STS in veterinary medicine.

Retrospective evaluation of sequential outpatient chemotherapy for advanced gastric cancer.

BACKGROUND/AIM: Due to the recent development of several promising chemotherapeutic agents, such as S-1, irinotecan (CPT-11) and paclitaxel, response rates for advanced gastric cancer to chemotherapy have improved. Thus far, however, the efficacy and survival benefits of sequential chemotherapy using these agents have not been evaluated. An additional benefit of outpatient sequential chemotherapy, that is, without hospitalization, would be its contribution to the maintenance of patients' social activities. The aim of this study was to retrospectively evaluate sequential outpatient chemotherapy for advanced gastric cancer. PATIENTS AND METHODS: Patients with metastatic/recurrent gastric cancer treated with sequential outpatient chemotherapy were analyzed retrospectively. The sequential treatment consisted of S1-based chemotherapy as first-line therapy, low-dose CPT-11/CDDP as second-line therapy and weekly paclitaxel administration as third-line therapy. RESULTS: A series of 32 patients was enrolled in this study. During the sequential chemotherapy, all patients were treated at the outpatient ward of Kyoto University Hospital without hospitalization. The overall response rate was 37.5% and the median survival time was 523 days (95% confidence interval: 323-723 days). The progression-free survival for the three therapies was 135 days for S-1, 148 days for low-dose CPT-11/CDDP and 57 days for paclitaxel. Grade 4 neutropenia was observed in 1 patient (3.1%), and there were no treatment-related deaths. Univariate analysis showed that factors with significant impact on survival were pathological type (intestinal vs. diffuse), clinical response (responder vs. non-responder) and prior chemotherapy. Factors with p values <0.1, including pathological type, clinical response, prior chemotherapy and age (>75 vs. < or =75 years), were evaluated by multivariate analysis, which disclosed that clinical response and patient age were significantly related to patient prognosis. CONCLUSION: In terms of survival and maintenance of social activities of patients, outpatient sequential chemotherapy appears to be both feasible and effective for advanced gastric cancer. Although prospective analysis of sequential chemotherapy is difficult because of its complex treatment protocol, clinical trials to assess the survival benefits of second-line chemotherapy for advanced gastric cancer are clearly warranted.

SIAH1 causes growth arrest and apoptosis in hepatoma cells through beta-catenin degradation-dependent and -independent mechanisms.

We have previously shown that expression of SIAH1 is frequently down-regulated in HCCs and associated with their advanced stages. It has been shown that SIAH1 functions in the phosphorylation-independent degradation of beta-catenin and induces apoptosis and growth arrest. To examine if the effects of SIAH1 overexpression depend on the altered beta-catenin signaling pathway, we transferred the SIAH1 gene into three hepatoma cell lines with different genetic backgrounds: HepG2 (mutant beta-catenin), SNU475 (mutant AXIN1), and Huh7 cells (wild type beta-catenin and AXIN1). SIAH1 significantly decreased aberrant beta-catenin signal in HepG2 and SNU475 cells and induced growth arrest and apoptosis. However, SIAH1 also induced apoptosis in Huh7 cells, which retained a normal membranous distribution pattern of beta-catenin. Immunoblotting study demonstrated that SIAH1 also reduces the amount of PEG10 protein, which is known to be frequently overexpressed in HCC and to promote cell proliferation. These data suggest that PEG10 is another target protein of SIAH1 to induce apoptosis in hepatoma cells. Our results should lead to a better understanding of the relationship between deregulation of beta-catenin signals and hepatocarcinogenesis. Further investigations into the mechanisms by which SIAH1 promotes apoptosis and suppresses cell growth should also allow for the discovery of new therapeutic strategies.

[Combined chemotherapy with oral leucovorin (LV) + tegafur/uracil (UFT) and hepatic arterial infusion (HAI) therapy for liver metastasis of colorectal cancer].

The liver is the most frequent metastatic site from colorectal cancer, and the control of liver metastasis is an important issue in the treatment of progressive colorectal cancer. Hepatic arterial infusion (HAI) therapy can achieve a high drug concentration in the liver and relatively low level in the systemic circulation because of the first pass effect of the drug metabolism. With the high response rate, several reports have failed to show a significant survival benefit of HAI monotherapy, partially due to its inability to control extrahepatic metastasis. In this report, we used oral tegafur/uracil (UFT) and Leucovorin (LV) combined with HAI of 5-FU for four patients with liver metastasis of colorectal carcinoma. One of two patients with unresectable multiple hepatic metastases could undergo resectional surgery after 5 courses of this therapy. Two other cases in an adjuvant setting have been surviving free of tumors. In this series, adverse effects of this therapy were acceptable, including one case of grade 3 thrombocytopenia. The benefit of this combined therapy for survival in a case of liver metastasis from CRC remains to be evaluated. We are planning phase I and II clinical studies to evaluate the efficiency and feasibility of this combination therapy.

Suppression of VEGFR-3 signaling inhibits lymph node metastasis in gastric cancer.

In gastric cancer, lymph node metastasis is one of the major prognostic factors and forms the basis for surgical removal of local lymph nodes. Recently, several studies have demonstrated that overexpression of lymphangiogenic growth factor VEGF-C or VEGF-D induces tumor lymphangiogenesis and promotes lymphatic metastasis in mouse tumor models. We examined whether these processes could be inhibited in naturally metastatic tumors by blocking of their cognate receptor VEGFR-3 signaling pathway. Using a mouse orthotopic gastric cancer model which has a high frequency of lymph node metastasis, we estimated lymphatic vessels in gastric cancers by immunostaining for VEGFR-3 and other specific lymphatic markers, LYVE-1 and prox-1. Then we systemically administered anti-VEGFR-3 blocking antibodies. This treatment resulted in the inhibition of regional lymph node metastasis and reduction of lymphatic vessel density in the primary tumors. In addition, increased density of LYVE-1-positive lymphatic vessels of primary tumors was closely correlated with lymph node metastasis in human samples of gastric cancer. Antilymphangiogenesis by inhibiting VEGFR-3 signaling could provide a potential strategy for the prevention of lymph node metastasis in gastric cancer.