Suppression of hepatic tumor growth and metastasis by metronomic therapy in a rat model of hepatocellular carcinoma.

Although continuous low-dose (metronomic [MET]) therapy exerts anti-cancer efficacy in various cancer models, the effect of long-term MET therapy for hepatocellular carcinoma (HCC) remains unknown. This study assessed the long-term efficacy of MET on suppression of tumor growth and spontaneous metastasis in a rat model of HCC induced by administration of diethylnitrosamine for 16 wk. The rats were divided into 3 groups: MTD group received intraperitoneal (i.p.) injections of 40 mg/kg cyclophosphamide on days 1, 3, and 5 of a 21-day cycle; Control and MET groups received i.p. injections of saline and 20 mg/kg cyclophosphamide twice a week, respectively. Anti-tumor and anti-angiogenic effects and anti-metastatic mechanisms including matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) were evaluated. Twelve wk of MET therapy resulted in a significant reduction in intrahepatic tumors than control or MTD therapy. The MET group had fewer proliferating cell nuclear antigen-positive cells and decreased hypoxia-inducible factor-1α levels and microvessel density. Lung metastases were detected in 100%, 80%, and 42.9% in the control, MTD, and MET groups, respectively. MET therapy significantly decreased expression of TIMP-1, MMP-2 and -9. For mediators of pro-MMP-2 activation, MET therapy induced significant suppression in the TIMP-2 and MMP-14 level. The survival in the MET group was significantly prolonged compared to the control and MTD groups. Long-term MET scheduling suppresses tumor growth and metastasis via its potent anti-angiogenic properties and a decrease in MMPs and TIMPs activities. These results provide a rationale for long-term MET dosing in future clinical trials of HCC treatment.

Beneficial effect of metronomic chemotherapy on tumor suppression and survival in a rat model of hepatocellular carcinoma with liver cirrhosis.

PURPOSE: Recent studies have demonstrated that frequent, low-dose metronomic (MET) dosing of cytotoxic agents may not only be as efficient as conventional maximum tolerated dose (MTD) chemotherapy but also less toxic. In this study, we investigated the therapeutic effect and safety of MET chemotherapy using cyclophosphamide (CTX) in rats with chemically induced hepatocellular carcinoma (HCC). METHODS: Rats received weekly intraperitoneal (i.p.) injections of diethylnitrosamine during 16 weeks for induction of HCC. The rats were divided into three groups: MTD group received 40 mg/kg CTX i.p. injection on days 1, 3, and 5 of a 21-day cycle; Control and MET groups received saline and 20 mg/kg CTX i.p. injection twice a week, respectively. The growth-modulating effects and overall survival were compared between the groups. Anti-angiogenic effects were evaluated by a measurement of endothelial cell and VEGFR-2 expression. RESULTS: At 6 weeks of therapy, MTD and MET chemotherapy resulted in a significant reduction in tumor number and size compared with Control group. MET chemotherapy showed more prolonged survival than MTD chemotherapy and Control groups (P < 0.05). MET chemotherapy resulted in a significant decrease in both the micro-vessel density and endothelial proliferation index (P < 0.01). Furthermore, MET chemotherapy led to a greater decrease in VEGFR-2 expression at the mRNA and protein levels (P < 0.01). CONCLUSIONS: MET scheduling not only exhibits anti-tumor and anti-angiogenic effects, but also prolongs survival without major toxicities in a rat model of HCC. Our results suggest that MET chemotherapy has a high therapeutic value and should be considered for future clinical trials.

[The value of serum retinol-binding protein 4 levels for determining disease severity in patients with chronic liver disease].

BACKGROUNDS/AIMS: Serum retinol-binding protein 4 (RBP4) is known to be a specific transport protein for retinol, and has recently been reported to be associated with insulin resistance. Hyaluronic acid (HA) is a well-known marker of liver fibrosis. In this study, the degree to which serum RBP4 levels can be used to predict disease severity in patients with chronic liver disease (CLD) was evaluated. METHODS: Serum levels of RBP4 and HA were measured in 573 CLD patients [235 with chronic hepatitis (CH), 230 with liver cirrhosis Child-Pugh grade (Child) A, and 108 with liver cirrhosis with Child B and C] and 40 normal controls. RESULTS: The mean age of the whole cohort was 53.1 years and the causes of CLD were hepatitis B virus (61.9%), hepatitis C virus (9.8%), alcohol (9.0%), and nonalcoholic steatohepatitis (3.8%). Serum levels of RBP4 significantly reduced and HA increased with disease condition, from none (normal controls) to advanced cirrhosis (normal control: RBP4 4.3+/-0.1 mg/dL, HA 25.3+/-28.1 ng/mL; CH: RBP4 3.6+/-0.1 mg/dL, HA 75.5+/-7.8 ng/mL; cirrhosis with Child A: RBP4 2.6+/-0.1 mg/dL, HA 184.4+/-14.5 ng/mL; and cirrhosis with Child B and C: RBP4 1.6+/-0.1 mg/dL, HA 656.5+/-86.7 ng/mL; P<0.001, respectively). Serum RBP4 level was a distinguishing factor at the early stage of CLD between CH and Child A cirrhosis (post-hoc test; P<0.001) and was correlated with histological fibrosis score (n=80, P<0.05) and several biochemical factors. Antiviral therapy (n=45, median interval 1,205 days) resulted in an improvement in serum RBP4 levels (P=0.001). CONCLUSIONS: The results of our study suggest that RBP4 is a serologic marker for disease severity in patients with CLD. It could also be useful as an early marker of CLD and of the relative success of antiviral therapy.

Thy1-positive bone marrow stem cells express liver-specific genes in vitro and can mature into hepatocytes in vivo.

The bone marrow contains stem cells that have the potential to differentiate into a variety of organ-specific mature cells, including the liver and the pancreas. Recently, the origin of hepatic progenitors and hepatocytes was identified to be the bone marrow. However, evidence that describes which cells, among all bone marrow cells, differentiate into hepatocytes, has not yet been presented. Based on recent reports, hematopoietic and hepatic stem cells share characteristic markers such as CD34, c-kit, and Thy1. In particular, both hematopoietic and hepatic stem cells express the Thy1 antigen. We investigated whether rat Thy1-positive bone marrow cells express liver-specific genes in vitro, and whether transplanted Thy1 BM cells differentiate into mature hepatocytes in vivo. For collection of Thy1 cells from bone marrow, FITC-conjugated anti-Thy1.1 monoclonal antibody was used with a Fluorescence-Activated Cell Sorter system. A coculture system of 2 separate layers was used for culture of Thy bone marrow cells. Cultured Thy1 cells expressed albumin protein, which was analyzed by immunofluorescent staining. Thy1 bone marrow cells obtained from wild-type dipeptidyl peptidase IV (DPPIV(+)) male rat were directly transplanted into the injured liver of DPPIV mutant (DPPIV(-)) Fisher 344 female rats and differentiated into mature hepatocytes in recipient liver on 60 days. Donor-derived hepatocytes were confirmed by DPPIV staining and Y-chromsome in situ hybridization. Our results suggest that Thy1-positive bone marrow cells have the potential to generate liver-specific genes in vitro and can differentiate into mature hepatocytes in adult liver in vivo. Thy1-positive bone marrow stem cells may represent preexisting hepatocyte-specific stem cells.

Ground, sieved, and C18 modified monolithic silica particles for packing material of microcolumn high-performance liquid chromatography.

We here report a new type of stationary phase for microcolumns. C18 modified silica monolith particles were prepared by grinding and sieving the silica monolith followed by C18 modification and end-capping, and were used as packing material. Ground silica monolith particles were not spherical but irregular with some residual monolithic network structure. The separation efficiency of the stationary phase made of sieved monolith particles (5-10 microm) was better than that of the stationary phase made of unsieved particles. The microcolumn packed with the sieved C18 ground monolith particles (5-10 microm) showed quite good separation efficiency (height equivalent to theoretical plate, HETP, as low as 15 microm) and it was even superior to the microcolumn packed with a commercial spherical 5 microm C18 stationary phase. The column pressure drop of C18 monolith particles was about two-third of that of the commercial spherical C18 phase. The preparation method of C18 stationary phase with ground and sieved silica monolith particles presumably suggests advantages of simplicity and convenience in modification and washing procedures compared to bulk silica monolith. It also showed both improved separation efficiency and low back pressure.