The irradiated-fibroblasts elicit immune response against tumor in a murine colon cancer model.

Abstract

OBJECTIVE: The breaking of immune tolerance against tumor stromal fibroblasts should be a useful approach for cancer immunotherapy. The primary objective of this study was to verify whether irradiated-fibroblasts could induce an anti-tumor immune response in vivo. MATERIALS AND METHODS: Normal fibroblasts were irradiated with 25Gy; their expressions of a-SMA, HMGB1 and calreticulin were assessed by Western blot. Mice were immunized with irradiated-fibroblasts and then challenged with CT26 colon carcinoma. Auto-antibodies were assessed by flow cytometric. The inhibition of proliferation of tumor cells by purified immunoglobulins was investigated. RESULTS: The irradiated-fibroblasts expressed HMGB1, calreticulin and α-SMA. The irradiated-fibroblasts were effective in affording protection from tumor onset and growth. The immunized sera exhibited positive staining for tumor cells in flow cytometric analysis. The purified immunoglobulins from immunized mice inhibited the proliferation of CT26 tumor cells in vitro. CONCLUSIONS: All these suggest that irradiated-fibroblasts could induce an anti-tumor immune response.