2006 Fiscal Year Final Research Report Summary
Development of immortalized allogenic dendritic cells expressing telomerase for treatment of gastroenterological cancer
| Project/Area Number |
17591401
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Digestive surgery
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| Research Institution | Okayama University |
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Principal Investigator |
KAGAWA Shunsuke Okayama University, Hospital, Assistant Professor, 医学部・歯学部附属病院, 助手 (00362971)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Toshiyoshi Okayama University, Hospital, Associate Professor, 医学部・歯学部附属病院, 助教授 (00304303)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Telomerase / Adenovirus / hTERT / Virotherapy / Gene therapy / Diagnostics |
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| Research Abstract |
Dendritic cells (DCs) are the most potent antigen-presenting cells and acquire cellular antigens and danger signals from dying cells to initiate antitumor immune responses via direct cell to cell interaction and cytokine production. Despite such antitumor efficacy, the optimal means of DC priming is unknown. In the present study, we compared three methods of tumor preparation as a source of cell-derived antigen for DC priming: virus-induced oncolysis, drug-induced apoptosis, and freeze thaw lysis. We reported previously that that telomerase-specific replication-competent adenovirus (Telomelysin, OBP-301) induces selective El expression and efficiently kills human cancer cells but not normal human fibroblasts. Morphological analysis showed that OBP-301-mediated cell death is different from apoptosis. Immature DCs generated in the presence of IL-4 and GM-CSF from monocytes of healthy individuals were pulsed with either H1299 human lung cancer cells infected with OBP-301, H1299 cells trea
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ted with chemotherapeutic agent (docetaxel), or freeze-thawed H1299 cells. IFN-y release into the supernatants, determined by ELISA, was used to assess the expression of antigens by DCs. OBP-301-infected cells stimulated DCs to produce approximately eight-fold more IFN-7 than docetaxel-treated apoptotic cells. In contrast, freeze-thaw lysis did not stimulate IFN-y release. We further examined by mixed lymphocyte tumor culture (MLTC) whether OBP-301-infected H 1299 cells could induce cytotoxic T-lymphocytes (CTL). The CTL assay demonstrated that OBP-301-infected H1299 cells efficiently induced CTL specific for H1299 cells. We found that the supernatants of MLTC with oncolytic cells up-regulated the endogenous expression of the proteasome activator PA28 in tumor cells. Furthermore, uric acid levels were elevated in OBP-301-infected H 1299 cells compared with docetaxel-treated cells, suggesting that uric acid acts as a danger signal triggering the immune response to the tumor. Our data suggest that oncolysis caused by conditionally replication-selective adenovirus might be the most effective stimulus for immature DCs to induce specific activity against human cancer cells. Less
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