Jimi Mitobe

Current Immunotherapeutic Approaches in Pancreatic Cancer

Pancreatic cancer is a highly aggressive and notoriously difficult to treat. As the vast majority of patients are diagnosed at advanced stage of the disease, only a small population is curative by surgical resection. Although gemcitabine-based chemotherapy is typically offered as standard of care, most patients do not survive longer than 6 months. Thus, new therapeutic approaches are needed. Pancreatic cancer cells that develop gemcitabine resistance would still be suitable targets for immunotherapy. Therefore, one promising treatment approach may be immunotherapy that is designed to target pancreatic-cancer-associated antigens. In this paper, we detail recent work in immunotherapy and the advances in concept of combination therapy of immunotherapy and chemotherapy. We offer our perspective on how to increase the clinical efficacy of immunotherapies for pancreatic cancer.

Combined TLR2/4-Activated Dendritic/Tumor Cell Fusions Induce Augmented Cytotoxic T Lymphocytes

Induction of antitumor immunity by dendritic cell (DC)-tumor fusion cells (DC/tumor) can be modulated by their activation status. In this study, to address optimal status of DC/tumor to induce efficient antigen-specific cytotoxic T lymphocytes (CTLs), we have created various types of DC/tumor: 1) un-activated DC/tumor; 2) penicillin-killed Streptococcus pyogenes (OK-432; TLR4 agonist)-activated DC/tumor; 3) protein-bound polysaccharides isolated from Coriolus versicolor (PSK; TLR2 agonist)-activated DC/tumor; and 4) Combined OK-432- and PSK-activated DC/tumor. Moreover, we assessed the effects of TGF-β1 derived from DC/tumor on the induction of MUC1-specific CTLs. Combined TLR2- and TLR4-activated DC/tumor overcame immune-suppressive effect of TGF-β1 in comparison to those single activated or un-activated DC/tumor as demonstrated by: 1) up-regulation of MHC class II and CD86 expression on DC/tumor; 2) increased fusion efficiency; 3) increased production of fusions derived IL-12p70; 4) activation of CD4+ and CD8+ T cells that produce high levels of IFN-γ; 5) augmented induction of CTL activity specific for MUC1; and 6) superior efficacy in inhibiting CD4+CD25+Foxp3+ T cell generation. However, DC/tumor-derived TGF-β1 reduced the efficacy of DC/tumor vaccine in vitro. Incorporating combined TLRs-activation and TGF-β1-blockade of DC/tumor may enhance the effectiveness of DC/tumor-based cancer vaccines and have the potential applicability to the field of adoptive immunotherapy.

Long-Term Alteration of Intestinal Microbiota in Patients with Ulcerative Colitis by Antibiotic Combination Therapy

Previous work has demonstrated that intestinal bacteria, such as Fusobacterium varium (F. varium), contribute to the clinical activity in ulcerative colitis (UC); thus, an antibiotic combination therapy (amoxicillin, tetracycline, and metronidazole (ATM)) against F. varium can induce and maintain UC remission. Therefore, we investigated whether ATM therapy induces a long-term alteration of intestinal microbiota in patients with UC. Patients with UC were enrolled in a multicenter, randomized, double-blind, placebo-controlled study. Biopsy samples at the beginning of the trial and again at 3 months after treatment completion were randomly obtained from 20 patients. The terminal restriction fragment length polymorphism (T-RFLP) in mucosa-associated bacterial components was examined to assess the alteration of the intestinal microbiota. Profile changes of T-RFLP in mucosa-associated bacterial components were found in 10 of 12 patients in the treatment group and in none of 8 in the placebo group. Dice similarity coefficients using the unweighted pair group method with arithmetic averages (Dice-UPGMA) confirmed that the similarity of mucosal microbiota from the descending colon was significantly decreased after the ATM therapy, and this change was maintained for at least 3 months. Moreover, at 3 months after treatment completion, the F. varium/β-actin ratio, examined by real-time PCR using nested PCR products from biopsy samples, was reduced less than 40% in 8 of 12 treated patients, which was higher, but not significantly, than in 4 of 8 patients in the placebo group. Together, these results suggest that ATM therapy induces long-term alterations in the intestinal microbiota of patients with UC, which may be associated, at least in part, with clinical effects of the therapy.

Clinicopathological investigation of lymph node metastasis predictors in superficial esophageal squamous cell carcinoma with a focus on evaluation of lympho-vascular invasion.

Abstract Objective. Reliable indicators of the risk of lymph node metastasis (LNM) in superficial esophageal squamous cell carcinoma (sESCC: intramucosal and submucosal invasive carcinoma) may contribute to assist optimal clinical decision-making for treating sESCC. In esophageal cancer, there is a possibility of metastasis, even in sESCC, and careful evaluation is needed when making a pathological diagnosis. In this study, we objectively evaluated predictive factors of LNM. Materials and methods. A total of 110 consecutive sESCC cases were obtained. We evaluated candidate predictive factors of LNM as follows: (1) maximum tumor diameter; (2) macroscopic type; (3) depth of tumor invasion; (4) histological differentiation; (5) infiltrative growth pattern; (6) tumor budding; (7) lymphatic invasion; (8) venous invasion and (9) lympho-vascular invasion (LVI). Both Elastica–Van Gieson staining (EVG) and immunohistochemistry (IHC: D2-40, CD31, CD34) were used to evaluate invasion into the lympho-vascular spaces. For statistical analyses, single and multiple logistic regression were performed. Results. LNM was observed in 37 cases (33.6%). LVI using EVG and IHC was the strongest independent predictor of LNM with an odds ratio of 12.01. Analysis of the relationship between LVI using EVG and IHC and LNM showed a negative predictive value of 94.6%. Conclusions. Evaluation of LVI using EVG and IHC may contribute to predict LNM in sESCC.

Augmentation of Antitumor Immunity by Fusions of Ethanol-Treated Tumor Cells and Dendritic Cells Stimulated via Dual TLRs through TGF-β1 Blockade and IL-12p70 Production

The therapeutic efficacy of fusion cell (FC)-based cancer vaccine generated with whole tumor cells and dendritic cells (DCs) requires the improved immunogenicity of both cells. Treatment of whole tumor cells with ethanol resulted in blockade of immune-suppressive soluble factors such as transforming growth factor (TGF)-β1, vascular endothelial growth factor, and IL-10 without decreased expression of major histocompatibility complex (MHC) class I and the MUC1 tumor-associated antigen. Moreover, the ethanol-treated tumor cells expressed “eat-me” signals such as calreticulin (CRT) on the cell surface and released immunostimulatory factors such as heat shock protein (HSP)90α and high-mobility group box 1 (HMGB1). A dual stimulation of protein-bound polysaccharides isolated from Coriolus versicolor (TLR2 agonist) and penicillin-inactivated Streptococcus pyogenes (TLR4 agonist) led human monocyte-derived DCs to produce HSP90α and multiple cytokines such as IL-12p70 and IL-10. Interestingly, incorporating ethanol-treated tumor cells and TLRs-stimulated DCs during the fusion process promoted fusion efficiency and up-regulated MHC class II molecules on a per fusion basis. Moreover, fusions of ethanol-treated tumor cells and dual TLRs-stimulated DCs (E-tumor/FCs) inhibited the production of multiple immune-suppressive soluble factors including TGF-β1 and up-regulated the production of IL-12p70 and HSP90α. Most importantly, E-tumor/FCs activated T cells capable of producing high levels of IFN-γ, resulting in augmented MUC1-specific CTL induction. Collectively, our results illustrate the synergy between ethanol-treated whole tumor cells and dual TLRs-stimulated DCs in inducing augmented CTL responses in vitro by FC preparations. The alternative system is simple and may provide a platform for adoptive immunotherapy.

Hepatic stellate cells that coexpress LRAT and CRBP-1 partially contribute to portal fibrogenesis in patients with human viral hepatitis.

Precisely what type of cells mainly contributes to portal fibrosis, especially in chronic viral hepatitis, such as hepatic stellate cells (HSCs) in the parenchyma or myofibroblasts in the portal area, still remains unclear. It is necessary to clarify the characteristics of cells that contribute to portal fibrosis in order to determine the mechanism of portal fibrogenesis and to develop a therapeutic target for portal fibrosis. This study was undertaken to examine whether LRAT+/CRBP‐1+ HSCs contribute to portal fibrosis on viral hepatitis.

Long-term management of gemcitabine in a patient with advanced pancreatic cancer undergoing haemodialysis

Abstract Gemcitabine application for patients with impaired renal function or undergoing haemodialysis will increase if the efficacy and safety are proved as the treatment for pancreatic cancer of these patients. However, there is no guideline about the usage of gemcitabine in patients with impaired renal function or haemodialysis. We report the case of a 70-year-old man with advanced pancreatic cancer undergoing haemodialysis. After discontinuation of 100% or 80% dosage, 60% dose of gemcitabine was administered biweekly. Serum carbohydrate antigen 19-9 and carcinoembryonic antigen levels were marked by slight variations and abdominal computed tomography (CT) showed the tumour size hardly changed. We administered gemcitabine for the patient 14 times in total, and he survived over 8 months from the definitive diagnosis. These findings confirm the efficacy and safety of treatment with a biweekly 60% dose of gemcitabine for patients with advanced pancreatic cancer undergoing haemodialysis in the face of dose modification.

The utility of balloon enteroscopy in the diagnosis of histiocytic sarcoma of the small intestine: A case report

The diagnosis of the rare neoplasm histiocytic sarcoma (HS) relies on morphology and the presence of immunophenotypic features of histiocytic lineage. More than 57 cases, including 16 cases involving the gastrointestinal (GI) tract, have been described since the World Health Organization issued its classification system for tumors of hematopoietic and lymphoid tissue in 2001. HS is often diagnosed in its late stages, at which point the prognosis is poor. Only a small proportion of these patients can undergo surgical resection with curative intent. The present report describes how HS can be diagnosed at a stage of favorable prognosis using balloon enteroscopy (BE), thereby enabling surgical resection before the development of metastases. This strategy is reviewed in the setting of a patient with jejunal HS, followed by a discussion of data from 16 other reported cases of GI HS.