Taro Takami

Loss of Hepatocyte Growth Factor/c-Met Signaling Pathway Accelerates Early Stages of N-nitrosodiethylamine-Induced Hepatocarcinogenesis

Hepatocyte growth factor (HGF) has been reported to have both positive and negative effects on carcinogenesis. Here, we show that the loss of c-Met signaling in hepatocytes enhanced rather than suppressed the early stages of chemical hepatocarcinogenesis. c-Met conditional knockout mice (c-metfl/fl, AlbCre+/-; MetLivKO) treated with N-nitrosodiethylamine developed significantly more and bigger tumors and with a shorter latency compared with control (w/w, AlbCre+/-; Cre-Ctrl) mice. Accelerated tumor development was associated with increased rate of cell proliferation and prolonged activation of epidermal growth factor receptor (EGFR) signaling. MetLivKO livers treated with N-nitrosodiethylamine also displayed elevated lipid peroxidation, decreased ratio of reduced glutathione to oxidized glutathione, and up-regulation of superoxide dismutase 1 and heat shock protein 70, all consistent with increased oxidative stress. Likewise, gene expression profiling done at 3 and 5 months after N-nitrosodiethylamine treatment revealed up-regulation of genes associated with cell proliferation and stress responses in c-Met mutant livers. The negative effects of c-Met deficiency were reversed by chronic p.o. administration of antioxidant N-acetyl-L-cysteine. N-acetyl-L-cysteine blocked the EGFR activation and reduced the N-nitrosodiethylamine-initiated hepatocarcinogenesis to the levels of Cre-Ctrl mice. These results argue that intact HGF/c-Met signaling is essential for maintaining normal redox homeostasis in the liver and has tumor suppressor effect(s) during the early stages of N-nitrosodiethylamine-induced hepatocarcinogenesis.

Hepatocellular carcinoma with nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) was originally believed to be a benign disease. However, it has been recently revealed that NASH could lead to irreversible liver disease in some patients. We report an unusual case of hepatocellular carcinoma (HCC) in a 76-year-old man with NASH. He had no history of alcohol consumption, drug use, or blood transfusion. He was negative for all serological viral markers and autoantibodies. In addition, he was obese (body mass index [BMI], 30.75 kg/m2) and had type 2 diabetes mellitus. A liver biopsy specimen showed moderate steatosis with necroinflammatory changes, ballooning degeneration, Mallory bodies, pericellular fibrosis, and evidence of nodular regeneration. He was diagnosed with NASH with cirrhosis. Simultaneously, a liver tumor, measuring 19 mm in diameter, was detected in segment 6. A tumor biopsy specimen revealed well-differentiated HCC, and imaging modalities confirmed the characteristics of HCC. To our knowledge, ten patients who had HCC with NASH were reported. In all patients with NASH and HCC, cirrhosis was present. Patients with NASH and cirrhosis may progress to HCC, and regular screening, based on tumor markers and imaging modalities, is needed to detect HCC in patients with NASH and cirrhosis.

Prognostic factors in patients with advanced hepatocellular carcinoma receiving hepatic arterial infusion chemotherapy

BackgroundThe prognosis of patients with advanced hepatocellular carcinoma (HCC) is poor. We aimed to clarify the prognostic factors in patients with advanced HCC receiving hepatic arterial infusion chemotherapy (HAIC).MethodsForty-four HCC patients were treated with HAIC, using low-dose cisplatin (CDDP) and 5-fluorouracil (5-FU) with/without leucovorin (or isovorin). Of these 44 patients, 15 received low-dose CDDP and 5-FU, and 29 received low-dose CDDP, 5-FU, and leucovorin or isovorin. Prognostic factors were evaluated by univariate and multivariate analyses of patient and disease characteristics.ResultsOf all patients, 5 and 12 patients respectively, exhibited a complete response (CR) and a partial response (PR) (response rate, 38%). The response rate (48.3%) in the low-dose CDDP and 5-FU with leucovorin/isovorin group was significantly better than that (20%) in the low-dose CDDP and 5-FU group (P = 0.002). The 1-, 2-, 3-, and 5-year cumulative survival rates of the 44 patients were 39%, 18%, 12%, and 9%, respectively. The regimen using low-dose CDDP and 5-FU with leucovorin/isovorin tended to improve survival rates (P = 0.097). Univariate and multivariate analyses showed the same variables—the Child-Pugh score (P = 0.013, P = 0.018), α-fetoprotein (AFP) level (P = 0.010, P = 0.009), and therapeutic effect after HAIC (P = 0.003, P = 0.01), respectively, to be significant prognostic factors.ConclusionsPatients who had advanced HCC with favorable hepatic reserve capacity and a lower AFP level were suitable candidates for HAIC. Moreover, the regimen using low-dose CDDP and 5-FU with leucovorin/isovorin may be suitable for advanced HCC patients, because of the improvement in the response rate and survival compared with the low-dose CDDP and 5-FU regimen without leucovorin/isovorin.

Iron regulation by hepatocytes and free radicals

Iron is an essential metallic microelement for life. However, iron overload is toxic. The liver serves an important role as a storehouse for iron in the body. About 20–25 mg of iron is required each day for hemoglobin synthesis. To maintain iron homeostasis, transferrin and transferrin receptors are primarily involved in the uptake of iron into hepatocytes, ferritin in its storage, and ferroportin in its export. Moreover, hepcidin controls ferroportin and plays a central role in the iron metabolism. Excess “free” reactive iron produces damaging free radicals via Fenton or Harber-Weiss reactions. Produced free radicals attack cellular proteins, lipids and nucleic acid. Several detoxification system and anti-oxidant defense mechanisms exist to prevent cellular damage by free radicals. Excessive free radicals can lead to hepatocellular damage, liver fibrosis, and hepatocarcinogenesis.

Canine mesenchymal stem cells show antioxidant properties against thioacetamide-induced liver injury in vitro and in vivo

To overcome current limitations of therapy for liver diseases, cell‐based therapies using mesenchymal stem cells (MSC) have been attempted through basic and clinical approaches. Oxidative stress is a crucial factor in hepatology, and reactive oxygen species (ROS) are well‐established molecules responsible for its deleterious effects. The antioxidant properties of MSC were recently demonstrated, and therefore we examined the antioxidant activity of canine MSC (cMSC), their effects on isolated hepatocytes in vitro and their curative potential against thioacetamide (TAA)‐induced liver injury in vivo.

Percutaneous radiofrequency ablation with cooled electrodes combined with hepatic arterial balloon occlusion in hepatocellular carcinoma

BackgroundWe have reported that percutaneous radiofrequency ablation (RFA) with balloon occlusion of the hepatic artery (balloon-occluded RFA), using an expandable electrode, increases the coagulation area. In this study, we investigated the efficacy of balloon-occluded RFA and balloon-microcatheter-occluded RFA, using a cool RF single electrode.MethodsWe studies 41 patients with 47 hepatocellular carcinoma (HCC) lesions. We treated 28 patients (32 nodules) with balloon-occluded RFA, 5 patients (6 nodules) with balloon-microcatheter-occluded RFA, and 8 patients (9 nodules) with standard RFA. Initial therapeutic efficacy was evaluated with dynamic computed tomography performed 1 week after one session of treatment.ResultsOne session of treatment was done for 20 nodules (62.5%) in the balloon-occluded RFA group and for 4 nodules (66.7%) in the balloon-microcatheter-occluded RFA group. We compared the coagulation diameter for balloon-occluded RFA (7 nodules), balloon-microcatheter-occluded RFA (6 nodules), and standard RFA (9 nodules) after one application cycle (12 min). The greatest dimension of the area coagulated by balloon-occluded RFA was significantly larger (greatest long-axis dimension, 47.6 ± 7.8 mm; greatest short-axis dimension, 33.4 ± 7.5 mm) than that coagulated by standard RFA (greatest long-axis dimension, 35.3 ± 4.7 mm; greatest short-axis dimension, 25.9 ± 3.7 mm; P = 0.002 for greatest long-axis dimension; P = 0.041 for greatest short-axis dimension). However, there was significant difference only in the greatest short-axis dimension of the area coagulated comparing balloon-microcatheter-occluded RFA and standard RFA.ConclusionsWe consider balloon-occluded RFA using a cool RF electrode to be superior to standard RFA for the treatment of HCC, especially when larger coagulation volumes are required.

Senescence marker protein 30 (SMP30)/regucalcin (RGN) expression decreases with aging, acute liver injuries and tumors in zebrafish

Senescence marker protein 30 (SMP30)/regucalcin (RGN) is known to be related to aging, hepatocyte proliferation and tumorigenesis. However, expression and function of non-mammalian SMP30/RGN is poorly understood. We found that zebrafish SMP30/RGN mRNA expression decreases with aging, partial hepatectomy and thioacetamide-induced acute liver injury. SMP30/RGN expression was also greatly decreased in a zebrafish liver cell line. In addition, we induced liver tumors in adult zebrafish by administering diethylnitrosamine. Decreased expression was observed in foci, hepatocellular carcinomas, cholangiocellular carcinomas and mixed tumors as compared to the surrounding area. We thus showed the importance of SMP30/RGN in liver proliferation and tumorigenesis.

Arterial infusion chemotherapy using cisplatin, 5-fluorouracil, and isovorin for patients with advanced hepatocellular carcinoma, pilot study: Is a high dose of the biochemical modulator effective?

The authors report the efficacy of arterial infusion chemotherapy using cisplatin (CDDP), 5-fluorouracil (5-FU), and leucovorin (LV) for patients with advanced hepatocellular carcinoma (HCC). In this study, we evaluated the efficacy of our regimen with high-dose LV, using isovorin (IV) (high dose group), comparing the previous regimen (low-dose LV; low dose group). This is a retrospective, historical, and non-controlled trial. In the high dose group (n=15), one course of chemotherapy consisted of the daily administration of CDDP (10 mg/1 h, for 5 days) and IV (12.5 mg/10 min, for 5 days) followed by 5-FU (250 mg/5 h, for 5 days). In the low dose group (n=9), changing to the administration of LV (12 mg/day), the same regimen was employed. In principle, we did this 20 times. In the high dose group, complete response (CR) was found in two patients, and partial response (PR) in six patients. Thus, the response rate was 53%. In the low dose group, CR was found in two patients, and PR in three patients. Thus, the response rate was 56%. There were no significant differences in the response rate (P=0.71), the survival rate (P=0.29) and the toxicity between the two groups. We considered the recommended dose of LV to be 12 mg/day in our regimen, although this is a preliminary study.

Enhanced survival of mice infused with bone marrow‐derived as compared with adipose‐derived mesenchymal stem cells

Less invasive therapies using mesenchymal stem cells (MSC) are being developed to treat patients with severe liver cirrhosis. MSC constitute a promising cell source for regenerative therapy and are frequently isolated from bone marrow (BMSC) or adipose tissue (ASC). Therefore, this study assessed the characteristics of these two cell types and their safety for cell infusion.

Highly sensitive stool DNA testing of Fusobacterium nucleatum as a marker for detection of colorectal tumours in a Japanese population.

Background Accumulating evidence shows an over-abundance of Fusobacterium nucleatum in colorectal tumour tissues. Although stool DNA testing of Fusobacterium nucleatum might be a potential marker for the detection of colorectal tumours, the difficulty in detecting Fusobacterium nucleatum in stool by conventional methods prevented further explorations. Therefore, we developed a droplet digital polymerase chain reaction (PCR) assay for detecting Fusobacterium nucleatum in stool and investigated its clinical utility in the management of colorectal tumours in a Japanese population. Methods Feces were collected from 60 healthy subjects (control group) and from 11 patients with colorectal non-advanced adenomas (non-advanced adenoma group), 19 patients with colorectal advanced adenoma/carcinoma in situ (advanced adenoma/carcinoma in situ (CIS) group) and 158 patients with colorectal cancer of stages I to IV (colorectal cancer group). Absolute copy numbers of Fusobacterium nucleatum were measured by droplet digital PCR. Results The median copy number of Fusobacterium nucleatum was 17.5 in the control group, 311 in the non-advanced adenoma group, 122 in the advanced adenoma/CIS group, and 317 in the colorectal cancer group. In comparison with that in the control group, the Fusobacterium nucleatum level was significantly higher in the non-advanced adenoma group, the advanced adenoma/CIS group and the colorectal cancer group. Conclusions This study illustrates the potential of stool DNA testing of Fusobacterium nucleatum by droplet digital PCR to detect individuals with colorectal tumours in a Japanese population.