Masahiko Tameda

Comparison of human gut microbiota in control subjects and patients with colorectal carcinoma in adenoma: Terminal restriction fragment length polymorphism and next-generation sequencing analyses

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in Japan. The etiology of CRC has been linked to numerous factors including genetic mutation, diet, life style, inflammation, and recently, the gut microbiota. However, CRC-associated gut microbiota is still largely unexamined. This study used terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing (NGS) to analyze and compare gut microbiota of Japanese control subjects and Japanese patients with carcinoma in adenoma. Stool samples were collected from 49 control subjects, 50 patients with colon adenoma, and 9 patients with colorectal cancer (3/9 with invasive cancer and 6/9 with carcinoma in adenoma) immediately before colonoscopy; DNA was extracted from each stool sample. Based on T-RFLP analysis, 12 subjects (six control and six carcinoma in adenoma subjects) were selected; their samples were used for NGS and species-level analysis. T-RFLP analysis showed no significant differences in bacterial population between control, adenoma and cancer groups. However, NGS revealed that i), control and carcinoma in adenoma subjects had different gut microbiota compositions, ii), one bacterial genus (Slackia) was significantly associated with the control group and four bacterial genera (Actinomyces, Atopobium, Fusobacterium, and Haemophilus) were significantly associated with the carcinoma-in-adenoma group, and iii), several bacterial species were significantly associated with each type (control: Eubacterium coprostanoligens; carcinoma in adenoma: Actinomyces odontolyticus, Bacteroides fragiles, Clostridium nexile, Fusobacterium varium, Haemophilus parainfluenzae, Prevotella stercorea, Streptococcus gordonii, and Veillonella dispar). Gut microbial properties differ between control subjects and carcinoma-in-adenoma patients in this Japanese population, suggesting that gut microbiota is related to CRC prevention and development.

Collagen triple helix repeat containing 1 is overexpressed in hepatocellular carcinoma and promotes cell proliferation and motility.

Although several therapeutic options are available for hepatocellular carcinoma (HCC), the outcome is still very poor. One reason is the complexity of signal transduction in the pathogenesis of HCC. The aim of this study was to identify new HCC-related genes and to investigate the functions of these genes in the pathogenesis and progression of HCC. Whole genomes of 15 surgically resected HCC specimens were examined for copy number alterations with comparative genomic hybridization. Gene expression was compared between HCC and normal liver tissues. The roles of the new genes in the progression of HCC were studied using cultured cell lines. Copy number gain in chromosome 8q was detected in 53% of HCC tissues examined. The gene that coded for collagen triple helix repeat containing 1 (CTHRC1), located at chromosome 8q22.3, was overexpressed in HCC compared with normal or liver cirrhosis tissues and identified as a new HCC-related gene. CTHRC1 deletion with short hairpin RNA significantly reduced proliferation, migration and invasion of HepG2 and Huh7 cells. In addition, mRNA of integrins β-2 and β-3 was downregulated, with deletion of CTHRC1 in these cells. Immunohistochemical staining on resected HCC tissues showing positive staining areas for CTHRC1 was significantly greater in poorly-differentiated HCC compared with well-differentiated HCC. Moreover, some cases showed strong staining for CTHRC1 in invasive areas of HCC. CTHRC1 has the potential to be a new biomarker for the aggressive HCC, and to be a new therapeutic target in treating HCC.

The expression and function of Toll-like receptors 3 and 9 in human colon carcinoma

Toll-like receptors (TLRs) are pattern-recognition receptors that are important in immune signaling. TLR recognition of various viral components including double-stranded RNA (TLR3) and unmethylated CpG-DNA (TLR9) plays a crucial role in cell survival. However, TLR expression and function in colon carcinoma cells are not well clarified. We investigated the expression of TLR3 and TLR9 in colon carcinoma cells using immunohistochemical methods. The function of TLR3 and TLR9 signaling in carcinoma cell lines was studied by direct cell stimulation with, or by cell transfection of, polyinosinic-polycytidylic acid (Poly I:C), a synthetic form of dsRNA, and by cell stimulation with CpG-oligodeoxynucleotides (ODNs), respectively. Positive TLR3 and TLR9 immunohistochemical staining was observed in 91 and 86% of human hepatocellular carcinoma (HCC) tissues, respectively. Cell surface stimulation of TLR3 with Poly I:C did not affect cell viability but it did activate NF-κB activity. By contrast, stimulation of intracellular TLRs with transfected Poly I:C significantly induced apoptosis. Cell surface stimulation of TLR9 with CpG-ODNs promoted cell proliferation, and, furthermore, these CpG-ODN TLR9 agonists reduced the cytotoxicity of the anticancer drug adriamycin. Cell surface expression of TLR3 and TLR9 in colon carcinoma cells plays an important role in cell survival. In addition, the proapoptotic activity of intracellularly expressed TLR3 may provide the possibility of using TLR3 agonists as novel clinical cytotoxic agents against colon carcinoma cells.

Des-γ-carboxy prothrombin ratio measured by P-11 and P-16 antibodies is a novel biomarker for hepatocellular carcinoma

Serum tumor markers, including α‐fetoprotein (AFP) and des‐γ‐carboxy prothrombin (DCP), are currently used in the diagnosis of hepatocellular carcinoma (HCC). There is, however, an aberrant increase in serum DCP in patients with obstructive jaundice, vitamin K deficiency or who are taking warfarin, resulting from a problem with the current methodology for measurement of this marker. This study aimed to elucidate the utility of a new biomarker, NX‐PVKA, for early diagnosis of HCC. A total of 96 patients were included in the HCC group. The control group included 138 liver cirrhosis (LC) patients without HCC. Serum concentrations of conventional DCP, AFP, AFP‐L3 and NX‐PVKA were measured. The NX‐PVKA ratio was calculated by dividing DCP by NX‐PVKA. In patients not taking warfarin, the area under the curve values of DCP, NX‐PVKA ratio, AFP and AFP‐L3 were 0.715, 0.690, 0.737 and 0.654, respectively, confirming the clinical utility of these markers in detecting HCC. In cases with DCP > 35 mAU/mL in particular, a significant increase in the NX‐PVKA ratio was observed in patients with HCC. In those cases, the cut‐off value for the NX‐PVKA ratio that was optimized by the receiver operating characteristic (ROC) curve was 1.15. In addition, the sensitivity and specificity for diagnosing HCC were 69.2% and 75.9%, respectively. Patients with HCC had higher NX‐PVKA ratios compared to patients with LC taking warfarin (P = 0.063). These results suggest that, when used in combination with DCP, the NX‐PVKA ratio is a promising novel marker for the detection of HCC.

Substitution in Amino Acid 70 of Hepatitis C Virus Core Protein Changes the Adipokine Profile via Toll-Like Receptor 2/4 Signaling

Background & Aims It has been suggested that amino acid (aa) substitution at position 70 from arginine (70R) to glutamine (70Q) in the genotype 1b hepatitis C virus (HCV) core protein is associated with insulin resistance and worse prognosis. However, the precise mechanism is still unclear. The aim of this study was to investigate the impact of the substitution at position 70 in HCV core protein on adipokine production by murine and human adipocytes. Methods The influence of treatment with HCV core protein (70R or 70Q) on adipokine production by both 3T3-L1 and human adipocytes were examined with real-time PCR and enzyme-linked immunosorbent assay (ELISA), and triglyceride content was also analyzed. The effects of toll-like receptor (TLR)2/4 inhibition on IL-6 production by 3T3-L1 induced by HCV core protein were examined. Results IL-6 production was significantly increased and adiponectin production was reduced without a change in triglyceride content by treatment with 70Q compared to 70R core protein in both murine and human adipocytes. IL-6 induction of 3T3-L1 cells treated by 70Q HCV core protein was significantly inhibited with anti-TLR2 antibody by 42%, and by TLR4 inhibitor by 40%. Conclusions Our study suggests that extracellular HCV core protein with substitution at position 70 enhanced IL-6 production and reduced adiponectin production from visceral adipose tissue, which can cause insulin resistance, hepatic steatosis, and ultimately development of HCC.

Human β-defensin-3 inhibits migration of colon cancer cells via downregulation of metastasis-associated 1 family, member 2 expression. Corrigendum in /ijo/46/4/1858

The innate immune system plays an important role as the first line of defense against many types of microbes. Accumulating reports suggest that human β-defensins (hBDs) are expressed by and have certain roles in some cancer cells. In this study, we investigated the roles of hBD-3 in colon cancer cells. The expression of hBD-3 was examined by reverse transcriptase-polymerase chain reaction analysis of colon cancer cell lines and immunohistochemical staining of colon cancer tissues. The effect of hBD-3 on proliferation of colon cancer was assessed using the MTT assay and a real-time cell analyzer, and the effect of hBD-3 on the migration of colon cancer cells was also examined. The results showed that hBD-3 is not expressed in colon cancer cells but is produced by tumor-infiltrating monocytes. Migration of colon cancer cells was significantly inhibited by hBD-3 in a dose-dependent manner, although proliferation of colon cancer cells was not affected by administration of hBD-3. Moreover, reduced expression of metastasis-associated 1 family, member 2 (MTA2) mRNA in colon cancer cells was associated with exposure to hBD-3. In conclusion, progression of colon cancer was inhibited by hBD-3 in a paracrine fashion. Therefore, hBD-3 may be a potent new agent for treating colon cancer.

Resveratrol sensitizes HepG2 cells to TRAIL-induced apoptosis.

Resveratrol is a natural polyphenol found in a wide variety of plants, including grapes, berries, and peanuts. Resveratrol can modulate a wide spectrum of molecular targets, including those involved in cancer signaling pathways. Here, we evaluated the role of resveratrol in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and examined the molecular mechanisms in the human hepatocellular carcinoma cell line HepG2. We used the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay to assess cell viability, flow cytometry to analyze cell cycle and apoptosis, and immunoblotting to detect protein expression. Resveratrol decreased cell viability at a concentration of 100 &mgr;mol/l or higher. At a concentration of 50 &mgr;mol/l, resveratrol induced S phase arrest of the cell cycle without apoptosis. In addition, phospho-AMPK increased significantly in a dose-dependent manner. Resveratrol was found to synergistically augment TRAIL-induced apoptosis. The rates of early apoptosis were 3.4, 9.6, and 49.6% on treatment with 50 &mgr;mol/l resveratrol, 10 ng/ml TRAIL, and both reagents, respectively. Resveratrol significantly downregulated the expression of survivin in a dose-dependent manner. In conclusion, we found that that resveratrol could augment TRAIL sensitivity by downregulating survivin. These results suggest that combination resveratrol with TRAIL may be an effective new strategy for the treatment of hepatocellular carcinoma.

The long-term effects of splenectomy and subsequent interferon therapy in patients with HCV-related liver cirrhosis

Partial splenic embolization (PSE) or splenectomy is widely performed to increase platelet counts for interferon (IFN) therapy. The aim of the present study was to evaluate the long-term effects of splenectomy and subsequent IFN therapy in patients with hepatitis C virus (HCV)-related liver cirrhosis (LC). The present study included 19 patients with HCV-related LC who underwent splenectomy for thrombo-cytopenia caused by hypersplenism. IFN therapy was performed in all 19 patients. The effects of splenectomy and subsequent IFN therapy on peripheral blood counts, liver function, carcinogenesis and survival rates were evaluated. Splenectomy was safely performed in all patients without major complications with the exception of portal thrombosis, which, however, it did not affect liver function when treated appropriately. Thrombocytopenia improved and IFN therapy could be performed in all the patients. A sustained virological response (SVR) was not observed in patients with genotype 1 although it was observed in 75% of patients with genotype 2. Due to severe side effects, five patients did not undergo scheduled IFN therapy. Over 5 years, the mean platelet number increased from 5.2 x 10(4) to 16.8 x 10(4)/mm3 (P<0.01) and liver function improved following splenectomy (albumin, Alb: 3.5‑3.8 g/dl; total bilirubin, T-Bil: 1.0‑0.7 mg/dl; prothrombin time, PT: 74.1‑97.7%; total cholesterol; T-cho: 140‑168 mg/dl; P<0.05). Hepatocellular carcinoma (HCC) occurred in only one patient during long‑term observation and follow‑up of the patients not presenting with HCC at entry. The results of the present study demonstrate that splenectomy followed by interferon therapy could be beneficial in patients with HCV-related LC.

Epigenetic regulation of proliferation and invasion in hepatocellular carcinoma cells by CBP/p300 histone acetyltransferase activity

Altered epigenetic control of gene expression plays a substantial role in tumor development and progression. Accumulating studies suggest that somatic mutations of CREB binding proteins (CBP)/p300 occur in some cancer cells. CBP/p300 possess histone acetyltransferase (HAT) activity, and are involved in many cellular processes. In this study, we investigated the expression and functional role of CBP/p300 in hepatocellular carcinoma (HCC) using the specific inhibitor C646 of CBP/p300 HAT activity. We examined its effect on several apoptosis-related proteins and invasion-related genes. The results showed that CBP/p300 were highly expressed in HCC tissues and that expression of p300, but not of CBP, was strongly correlated with the malignant character of HCC. C646 inhibited proliferation of HCC cell lines in a dose dependent manner. C646 significantly augmented TRAIL-induced apoptotic sensitivity, which was accompanied by reduced levels of survivin, in HepG2, HLE and SK-HEP1 cells. C646 significantly inhibited invasion of Huh7, HLE and SK-HEP1 cells. The level of matrix metallopeptidase 15 (MMP15) mRNA expression was significantly reduced, whereas the level of laminin alpha 3 (LAMA3) and secreted phosphoprotein 1 (SPP1) mRNA expression was significantly increased in Huh7 cells following exposure to C646. In conclusion, our results suggest that CBP/p300 HAT activity has an important role in malignant transformation, proliferation, apoptotic sensitivity and invasion in HCC. CBP/p300 could be a promising therapeutic target in HCC.

Isolated Metastasis of Hepatocellular Carcinoma in the Right Ventricle

A74-year-old man was admitted to our hospital for liver tumor found through magnetic resonance imaging (MRI). An electrocardiogram (EKG) revealed a negative T wave at V1-V4 on admission. The patient had alcoholic liver cirrhosis and diabetes mellitus. He was diagnosed with hepatocellular carcinoma (HCC) at age 70 years and underwent transcatheter arterial embolization and radiofrequency ablation. At age 71 years, HCC recurred, and the patient underwent hepatic resection. Contrast-enhanced computed tomography (CT), echocardiography, and MRI showed a tumor measuring 5 cm in size located in the right ventricle. In addition, the tumor was enhanced heterogeneously on CT. On MRI, the tumor showed low intensity in the T1-weighted image and slightly high intensity in the T2-weighted image (Figure A). The tumor appeared the same as the myocardium on gadolinium-enhanced MRI and showed no enhancement in the late phase. Positron emission tomography CT showed abnormal intake (standardized uptake value, 7.3) of 18-fluoro-2-deoxyglucose at the right ventricle (Figure B). There was no tumor in the right atrium or inferior vena cava. With these findings of image studies and the medical history, we diagnosed isolated metastasis of HCC in the right ventricle, but surgical resection was not performed because of the fear of high risk of death. His dyspnea developed gradually, and he died 9 months after diagnosis. Autopsy revealed that a soft tumor filled the right ventricle (Figure C). There was a tumor measuring 5 cm in the lateral segment of the liver and many small metastases in both lungs. Histologically, the hepatic and right ventricular tumors were moderately differentiated HCC that invaded the myocardium but not the right atrium or inferior vena cava. Previous studies showed that the majority of metastatic sites of HCC are the lungs (18%–55%), lymph nodes (26.7%–53%), bones (5.8%–38%), and adrenal glands (8.4%–15.4%). Cardiac metastasis of HCC is rare, with a rate of 1.2% in autopsy. Majority of cardiac metastases are direct and continuous extensions of intrahepatic HCC, and isolated cardiac metastases that are discontinuous with intrahepatic HCC are exceedingly rare. Kawakami et al reported 17 cases of isolated cardiac metastases that were located in the right ventricle, right atrium, and left ventricle in 10 (58.8%), 5 (29.4%),