Michihisa Moriguchi

Premature telomere shortening and impaired regenerative response in hepatocytes of individuals with NAFLD

Abstract: Aims: The risk factors associated with poor prognosis of nonalcoholic fatty liver disease (NAFLD) are not fully understood. Our aim was to assess the role of progressive hepatocellular telomere shortening in the clinical course of NAFLD.

The copper chelator trientine has an antiangiogenic effect against hepatocellular carcinoma, possibly through inhibition of interleukin‐8 production

Recent studies have revealed that copper is an important cofactor for several angiogenic agents. We examined the antiangiogenic effect against hepatocellular carcinoma (HCC) of the copper chelator trientine, especially focusing on the relationship between copper and interleukin‐8 (IL‐8), a potent angiogenic factor produced by hepatoma cells. HuH‐7 hepatoma cells were transplanted into nude mice and the growth of xenograft tumors was compared to and without administration of trientine. Using the resected tumor, microvessel density, apoptotic potential and proliferative activity were analyzed histologically and IL‐8 mRNA was semiquantified by RT‐PCR. In addition, HuH‐7 cells were cultured in control medium, medium supplemented with copper, medium supplemented with trientine and medium supplemented with both copper and trientine. Human IL‐8 levels were measured in the supernatants by ELISA. Using the extracts from cultured cells, IL‐8 mRNA was semiquantified by RT‐PCR. Trientine suppressed the growth of xenograft tumors significantly. Histologically, apoptotic potential was increased significantly and microvessel density, decreased. The production of IL‐8 from the tumor was suppressed by trientine. In vitro, IL‐8 production by HuH‐7 cells in copper‐containing medium was significantly greater than that in copper‐free medium, and this effect was weakened when trientine was added. However, no significant change was apparent when trientine was added to the medium alone. In conclusion, the chelating effect of trientine prevented copper from functioning as a cofactor in angiogenesis, which resulted in reduced IL‐8 production from HuH‐7 cells.

Role of cell-cycle turnover and oxidative stress in telomere shortening and cellular senescence in patients with chronic hepatitis C.

Background:  In addition to the telomere shortening that occurs with cell division, oxidative stress can damage or shorten telomeres and induce a condition termed premature senescence, possibly before telomeres become critically short. We investigated the effects of cell‐cycle turnover and oxidative stress on cellular senescence in hepatitis C virus (HCV)‐related chronic liver injury.

Centrosome aberration accompanied with p53 mutation can induce genetic instability in hepatocellular carcinoma.

Centrosome duplication is controlled in a cell cycle-specific manner and occurs once every cell cycle, thereby ensuring the balanced segregation of chromosomes during the mitotic phase. Numerical or structural abnormalities can arise in the centrosomes of malignant cells. Under defective cell cycle checkpoint systems, cancer cells with abnormal centrosomes can survive and re-enter the cell cycle, promoting unbalanced chromosome segregation and genetic instability. We investigated the centrosome aberrations in 33 patients diagnosed with hepatocellular carcinoma (HCC), using fluorescent pericentrin immunostaining. We also studied the p53 mutation, proliferative activity, and DNA ploidy in these cases. In normal hepatocytes, one centrosome was identified per cell as a round dot, usually in the vicinity of the nuclear membrane. However, in cancer cells from HCC tissue, several patterns of centrosome abnormalities occurred, including supernumerary centrosomes and centrosomes with an abnormal shape and size. Although the frequency of abnormal centrosomes in each tissue was relatively low compared with previous reports in other cancers, nevertheless, centrosome aberration was found in 30 out of 33 HCC tissues. The percentage of tumor cells with abnormal centrosomes was significantly higher in the nondiploid tumors (15.8±15.9‰) than in the diploid tumors (5.4±5.1‰) (P<0.05), and tended to be higher in the tumors with p53 mutation (11.6±13.1‰) than in those with wild-type p53 (5.6±6.8‰). Furthermore, 82% of nondiploid tumors exhibited p53 mutation, whereas only 41% of diploid tumors showed p53 mutation. The percentage of tumor cells with centrosome abnormalities were not related to tumor stage, size or proliferative activity. Therefore, our results indicate that hepatic cancer cells, under centrosome aberration and a defective checkpoint system possibly caused by p53 mutation, have the potential for genetic instability and aggressive behavior. This potential effect occurs irrespective of the tumor size or stage.

In vivo expression patterns of survivin and its splicing variants in chronic liver disease and hepatocellular carcinoma.

Abstract: Aim: Our aim was to clarify the significance of expression levels and post‐transcriptional splicing patterns of survivin during multistep hepatocarcinogenesis and tumor progression.

Lower levels of insulin‐like growth factor‐1 standard deviation score are associated with histological severity of non‐alcoholic fatty liver disease

Growth hormone (GH) deficiency may be associated with histological progression of non‐alcoholic fatty liver disease (NAFLD) which includes non‐alcoholic fatty liver (NAFL) and non‐alcoholic steatohepatitis (NASH). Insulin‐like growth factor 1 (IGF‐1) is mainly produced by hepatocytes and its secretion is stimulated by GH. Our aim was to determine whether more histologically advanced NAFLD is associated with low circulating levels of IGF‐1 in Japanese patients.

Blockade of interleukin 6 signalling ameliorates systemic insulin resistance through upregulation of glucose uptake in skeletal muscle and improves hepatic steatosis in high‐fat diet fed mice

Mice fed high‐fat diet (HFD) demonstrate obesity‐related systemic insulin resistance (IR). Aim of this study is to clarify the role of interleukin (IL)‐6 in IR in vivo focusing on skeletal muscle, adipose tissue and liver.

Genome-wide DNA methylation analysis in hepatocellular carcinoma

Epigenetic changes as well as genetic changes are mechanisms of tumorigenesis. We aimed to identify novel genes that are silenced by DNA hypermethylation in hepatocellular carcinoma (HCC). We screened for genes with promoter DNA hypermethylation using a genome-wide methylation microarray analysis in primary HCC (the discovery set). The microarray analysis revealed that there were 2,670 CpG sites that significantly differed in regards to the methylation level between the tumor and non-tumor liver tissues; 875 were significantly hypermethylated and 1,795 were significantly hypomethylated in the HCC tumors compared to the non‑tumor tissues. Further analyses using methylation-specific PCR, combined with expression analysis, in the validation set of primary HCC showed that, in addition to three known tumor-suppressor genes (APC, CDKN2A, and GSTP1), eight genes (AKR1B1, GRASP, MAP9, NXPE3, RSPH9, SPINT2, STEAP4, and ZNF154) were significantly hypermethylated and downregulated in the HCC tumors compared to the non-tumor liver tissues. Our results suggest that epigenetic silencing of these genes may be associated with HCC.

Phase I study of tivantinib in Japanese patients with advanced hepatocellular carcinoma: Distinctive pharmacokinetic profiles from other solid tumors.

A c‐Met inhibitor tivantinib is a candidate anticancer agent for patients with hepatocellular carcinoma (HCC), and CYP2C19 is the key metabolic enzyme for tivantinib. Previous Japanese phase I studies in patients with solid tumors (except HCC) recommend 360 mg twice daily (BID) and 240 mg BID for CYP2C19 extensive metabolizers (EM) and poor metabolizers (PM), respectively. In this study, Japanese patients with HCC in whom sorafenib treatment has failed were enrolled to evaluate the safety, tolerability and pharmacokinetics of oral tivantinib as a single agent. The dose was escalated separately in EM and PM, from 120 mg BID to 240 mg BID, in both capsule and tablet formulations. A total of 28 patients (EM: 21, PM: 7) received tivantinib. At a dose of 120 mg BID, dose‐limiting toxicities (DLT) did not develop in 12 EM (capsule: 6, tablet: 6) and 7 PM (capsule: 4, tablet: 3) during the DLT‐observation period (for 29 days after first dosing). At this dose, the pharmacokinetic profiles of tivantinib (AUC0–12 and Cmax) did not remarkably differ between EM and PM. When treated with 240 mg BID, 5 of 9 EM (capsule: 4 of 6, tablet: 1 of 3) developed neutropenia‐related DLT accompanying plasma tivantinib concentration higher than expected from the previous studies. Consequently, PM did not receive 240 mg BID. In conclusion, 120 mg BID of tivantinib is recommended among Japanese patients with HCC regardless of CYP2C19 phenotype.

Current status and future prospects of chemotherapy for advanced hepatocellular carcinoma

Sorafenib is the only drug that demonstrates a survival benefit for advanced hepatocellular carcinoma (HCC). However, the therapeutic effect of sorafenib is limited, so development of a more effective treatment method and second-line treatments is needed. Since the advent of sorafenib, clinical studies have been conducted with a variety of drugs and treatment methods, mainly with molecular targeted therapy, but almost all trials have ended in failure. The reasons for the difficulty in the development of a novel drug or treatment method include the diversity of mechanisms in the carcinogenesis and development of HCC, as well as the presence of background liver diseases such as chronic hepatitis and cirrhosis. Trials with immune-checkpoint inhibitors, which have an entirely different anti-tumor mechanism from that of molecular targeted drugs or cytotoxic drugs, have recently begun. Based on the results to date, clinical trials are now being conducted with enriched target subjects. In the future, providing more individualized treatment approaches for patients with advanced HCC will be essential.