Toshinao Takenouchi

Bio: Toshinao Takenouchi is an academic researcher. The author has contributed to research in topics: Genetic enhancement & Cytokine. The author has an hindex of 7, co-authored 10 publications receiving 310 citations.

Association of Fusobacterium nucleatum with clinical and molecular features in colorectal serrated pathway

Abstract: Human gut microbiota is being increasingly recognized as a player in colorectal cancers (CRCs). Evidence suggests that Fusobacterium nucleatum (F. nucleatum) may contribute to disease progression and is associated with CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) in CRCs; however, to date, there are no reports about the relationship between F. nucleatum and molecular features in the early stage of colorectal tumorigenesis. Therefore, we investigated the presence of F. nucleatum in premalignant colorectal lesions. In total, 465 premalignant lesions (343 serrated lesions and 122 non-serrated adenomas) and 511 CRCs were studied. We determined the presence of F. nucleatum and analyzed its association with molecular features including CIMP, MSI and microRNA-31 status. F. nucleatum was detected in 24% of hyperplastic polyps, 35% of sessile serrated adenomas (SSAs), 30% of traditional serrated adenomas (TSAs) and 33% of non-serrated adenomas. F. nucleatum was more frequently detected in CIMP-high premalignant lesions than in CIMP-low/zero lesions (p = 0.0023). In SSAs, F. nucleatum positivity increased gradually from sigmoid colon to cecum (p = 0.042). F. nucleatum positivity was significantly higher in CRCs (56%) than in premalignant lesions of any histological type (p < 0.0001). In conclusion, F. nucleatum was identified in premalignant colorectal lesions regardless of histopathology but was more frequently associated with CIMP-high lesions. Moreover, F. nucleatum positivity increased according to histological grade, suggesting that it may contribute to the progression of colorectal neoplasia. Our data also indicate that F. nucleatum positivity in SSAs may support the "colorectal continuum" concept.

Strong HLA-DR antigen expression on cancer cells relates to better prognosis of colorectal cancer patients: Possible involvement of c-myc suppression by interferon-gamma in situ.

Abstract: Strong HLA-DR antigen expression on cancer cells relates to better prognosis of colorectal cancer patients, although the precise mechanism is controversial. From an immunological point of view, HLA-DR antigen, induced by interferon (IFN)-gamma, is required for tumor-associated antigen recognition by CD4(+) T cells. For instance, as reported previously, the expression of HLA-DR antigen in normal colorectal epithelium immediately adjacent to cancer coincided significantly with the existence of IFN-gamma mRNA in the tissue. From another aspect, IFN-gamma has been revealed to suppress c-myc expression in vivo through a stat1-dependent mechanism, which is important for cell growth, cell cycle and chromosome instability. In the present study, strong HLA-DR-positive expression on cancer cells was significantly related to better prognosis for colorectal cancer patients. High IFN-gamma mRNA expression in situ indicated significantly less activation of c-myc mRNA expression. Further, HLA-DR antigen expression in cancer cells, as well as Dukes stages, was an independent factor for better long-term survival by multivariate analysis. Taken together, IFN-gamma, which induces HLA-DR antigens on the cell surface, also suppresses c-myc expression in situ, and is a possible non-immunological mechanism involved in the better long-term survival of colorectal cancer patients.

Diagnostic value of ¹⁸F-FDG PET/CT for lymph node metastasis of esophageal squamous cell carcinoma.

Abstract: This study investigated the diagnostic accuracy of hybrid positron-emission tomography/computed tomography (PET/CT) for lymph node (LN) metastasis of esophageal cancer. We also investigated the correlation between the size of metastatic nests and the detection by PET/CT. Two hundred and fifty-eight patients with esophageal squamous cell carcinoma who underwent esophagectomy with two- or three-field radical lymphadenectomy were analyzed retrospectively. We compared the diagnosis of preoperative PET/CT to the postoperative histopathological examination by each anatomical field (n = 1,231) in all 258 patients. The metastatic LNs resected from PET/CT positive fields were classified as belonging to the PET/CT-N-positive group (n = 229) and those from negative fields as belonging to the PET/CT-N-negative group (n = 352). The cross-sectional areas of metastatic nests were measured in each metastatic LN. Of the 1,231 fields, 275 (22 %) were positive for metastasis, including 581 LNs from 408 regional LN stations. The sensitivity and specificity of PET/CT examined by each anatomical field were 25.8 and 97.8 %, respectively. The median area of metastatic nests was 17.7 mm2 in the PET/CT-N-positive group, and 7.7 mm2 in the PET/CT-N-negative group (p < 0.001). A significant correlation was suggested between the nest size and detection by PET/CT. Because of its low sensitivity, PET/CT alone is insufficient to determine the surgical procedures, especially when considering reduction surgery.

Acquired immunity in nude mice induced by expression of the IL-2 or IL-4 gene in human pancreatic carcinoma cells and anti-tumor effect generated by in vivo gene transfer using retrovirus.

Abstract: We have examined the anti-tumor effect in nude mice caused by human pancreatic cancer cells (AsPC-1) modified to secrete IL-2 or IL-4. Loss of tumorigenicity of cytokine-producing, but not wild-type, cells was observed despite their unaltered in vitro proliferation rates; and these anti-tumor effects were dependent on the amount of cytokine released. Wild-type cells inoculated into mice which had rejected IL-2- or IL-4-producer cells showed significant growth retardation, while no retardation was detected when unrelated human colon carcinoma cells were inoculated. Histological examination of regressing IL-2- or IL-4-producing AsPC-1 tumors in nude mice revealed infiltration by CD11b-, but not CD90-, positive cells around the tumors. Treatment of nude mice with anti-asialoGM(1) antibody did not affect loss of tumorigenicity. Mice injected i.p. with IL-2- or IL-4-producing AsPC-1 cells did not die, in contrast to mice inoculated with wild-type cells. Injection of retrovirus-bearing IL-2, but not beta-galactosidase, gene into mice which had wild-type cells in the peritoneal cavity also significantly prolonged survival. Thus, expression of the IL-2 or IL-4 gene in AsPC-1 cells may generate tumor-specific acquired immunity, even in mature T cell-deficient conditions. An anti-tumor response can be induced by in vivo transfer of the IL-2 gene.

Impaired in vivo tumor growth of human pancreatic carcinoma cells retrovirally transduced with GM-CSF gene.

Abstract: We have examined the antitumor effect of human pancreatic carcinoma cells (AsPC-1) retrovirally transduced with mouse granulocyte macrophage-colony stimulating factor (GM-CSF) gene in nude mice. Growth retardation of the subcutaneous tumors of GM-CSF-producing AsPC-1 cells was observed, although their in vitro proliferation was not different from that of wild-type cells. Histological examination revealed infiltration of monocytic cells into the tumor of GM-CSF-producing cells, and they were shown to be mainly CD11b positive cells by immunohistochemical staining. The survival of the mice inoculated intraperitoneally with GM-CSF- producing AsPC-1 cells was significantly prolonged compared with that of the mice inoculated with wild-type AsPC-1 cells. Thus, the expression of GM-CSF gene in human pancreatic cells induced an antitumor effect in vivo even in the mature T cell-deficient condition.

Analysis of Fusobacterium persistence and antibiotic response in colorectal cancer

Abstract: Colorectal cancers comprise a complex mixture of malignant cells, nontransformed cells, and microorganisms. Fusobacterium nucleatum is among the most prevalent bacterial species in colorectal cancer tissues. Here we show that colonization of human colorectal cancers with Fusobacterium and its associated microbiome—including Bacteroides , Selenomonas , and Prevotella species—is maintained in distal metastases, demonstrating microbiome stability between paired primary and metastatic tumors. In situ hybridization analysis revealed that Fusobacterium is predominantly associated with cancer cells in the metastatic lesions. Mouse xenografts of human primary colorectal adenocarcinomas were found to retain viable Fusobacterium and its associated microbiome through successive passages. Treatment of mice bearing a colon cancer xenograft with the antibiotic metronidazole reduced Fusobacterium load, cancer cell proliferation, and overall tumor growth. These observations argue for further investigation of antimicrobial interventions as a potential treatment for patients with Fusobacterium -associated colorectal cancer.

Fusobacterium nucleatum in colorectal carcinoma tissue and patient prognosis

Abstract: Objective Accumulating evidence links the intestinal microbiota and colorectal carcinogenesis. Fusobacterium nucleatum may promote colorectal tumour growth and inhibit T cell-mediated immune responses against colorectal tumours. Thus, we hypothesised that the amount of F. nucleatum in colorectal carcinoma might be associated with worse clinical outcome. Design We used molecular pathological epidemiology database of 1069 rectal and colon cancer cases in the Nurses’ Health Study and the Health Professionals Follow-up Study, and measured F. nucleatum DNA in carcinoma tissue. Cox proportional hazards model was used to compute hazard ratio (HR), controlling for potential confounders, including microsatellite instability (MSI, mismatch repair deficiency), CpG island methylator phenotype (CIMP), KRAS , BRAF , and PIK3CA mutations, and LINE-1 hypomethylation (low-level methylation). Results Compared with F. nucleatum -negative cases, multivariable HRs (95% CI) for colorectal cancer-specific mortality in F. nucleatum -low cases and F. nucleatum -high cases were 1.25 (0.82 to 1.92) and 1.58 (1.04 to 2.39), respectively, (p for trend=0.020). The amount of F. nucleatum was associated with MSI-high (multivariable odd ratio (OR), 5.22; 95% CI 2.86 to 9.55) independent of CIMP and BRAF mutation status, whereas CIMP and BRAF mutation were associated with F. nucleatum only in univariate analyses (p Conclusions The amount of F. nucleatum DNA in colorectal cancer tissue is associated with shorter survival, and may potentially serve as a prognostic biomarker. Our data may have implications in developing cancer prevention and treatment strategies through targeting GI microflora by diet, probiotics and antibiotics.

Metagenomic and metabolomic analyses reveal distinct stage-specific phenotypes of the gut microbiota in colorectal cancer

Abstract: In most cases of sporadic colorectal cancers, tumorigenesis is a multistep process, involving genomic alterations in parallel with morphologic changes. In addition, accumulating evidence suggests that the human gut microbiome is linked to the development of colorectal cancer. Here we performed fecal metagenomic and metabolomic studies on samples from a large cohort of 616 participants who underwent colonoscopy to assess taxonomic and functional characteristics of gut microbiota and metabolites. Microbiome and metabolome shifts were apparent in cases of multiple polypoid adenomas and intramucosal carcinomas, in addition to more advanced lesions. We found two distinct patterns of microbiome elevations. First, the relative abundance of Fusobacterium nucleatum spp. was significantly (P < 0.005) elevated continuously from intramucosal carcinoma to more advanced stages. Second, Atopobium parvulum and Actinomyces odontolyticus, which co-occurred in intramucosal carcinomas, were significantly (P < 0.005) increased only in multiple polypoid adenomas and/or intramucosal carcinomas. Metabolome analyses showed that branched-chain amino acids and phenylalanine were significantly (P < 0.005) increased in intramucosal carcinomas and bile acids, including deoxycholate, were significantly (P < 0.005) elevated in multiple polypoid adenomas and/or intramucosal carcinomas. We identified metagenomic and metabolomic markers to discriminate cases of intramucosal carcinoma from the healthy controls. Our large-cohort multi-omics data indicate that shifts in the microbiome and metabolome occur from the very early stages of the development of colorectal cancer, which is of possible etiological and diagnostic importance. Colorectal cancer stages are associated with distinct microbial and metabolomic profiles that could shed light on cancer progression.

Gut microbiota in colorectal cancer: mechanisms of action and clinical applications

Abstract: Colorectal cancer (CRC) accounts for about 10% of all new cancer cases globally. Located at close proximity to the colorectal epithelium, the gut microbiota comprises a large population of microorganisms that interact with host cells to regulate many physiological processes, such as energy harvest, metabolism and immune response. Sequencing studies have revealed microbial compositional and ecological changes in patients with CRC, whereas functional studies in animal models have pinpointed the roles of several bacteria in colorectal carcinogenesis, including Fusobacterium nucleatum and certain strains of Escherichia coli and Bacteroides fragilis. These findings give new opportunities to take advantage of our knowledge on the gut microbiota for clinical applications, such as gut microbiota analysis as screening, prognostic or predictive biomarkers, or modulating microorganisms to prevent cancer, augment therapies and reduce adverse effects of treatment. This Review aims to provide an overview and discussion of the gut microbiota in colorectal neoplasia, including relevant mechanisms in microbiota-related carcinogenesis, the potential of utilizing the microbiota as CRC biomarkers, and the prospect for modulating the microbiota for CRC prevention or treatment. These scientific findings will pave the way to clinically translate the use of gut microbiota for CRC in the near future.