Immunization with aspartate-β-hydroxylase–loaded dendritic cells produces antitumor effects in a rat model of intrahepatic cholangiocarcinoma

Authors


  • Potential conflict of interest: Nothing to report.

  • This work was supported by CA-123544 (to J.R.W.) and CA-83650 (to A.E.S.) from the U.S. National Institutes of Health and a grant from the Uehara Memorial Foundation, Japan.

Abstract

Dendritic cells (DCs) capture and process proteins and present peptides on the cell surface in the context of major histocompatibility complex I and II molecules to induce antigen-specific T cell immune responses. The aims of this study were to (1) employ an expanded and purified DC population and load them with aspartate-β-hydroxylase (ASPH), a highly expressed tumor-associated cell surface protein, and (2) to determine if immunization induced antitumor effects in an orthotopic rat model of intrahepatic cholangiocarcinoma. Splenocytes were incubated with ASPH-coated beads and passed through a magnetic field to yield an 80% pure DC OX62+ population. This DC subset was stimulated with granulocyte-macrophage colony-stimulating factor, interleukin-4, CD40L, and interferon-γ, resulting in a 40-fold increase in interleukin-12A messenger RNA expression to subsequently generate a T helper 1–type immune response. After incubation with the cytokine cocktail, DCs were found to have matured, as demonstrated by increased expression of CD40, CD80, and CD86 costimulatory molecules. Immunization with ASPH-loaded DCs induced antigen-specific immunity. A clone of the parental tumorigenic rat BDEneu cholangiocyte cell line, designated BDEneu-CL24, was found to have the highest number of cells expressing this surface protein (97%); it maintained the same phenotypic characteristics of the parental cell line and was used to produce intrahepatic tumors in immunocompetent syngeneic Fisher-344 rats. Immunization with ASPH-loaded DCs generated cytotoxicity against cholangiocarcinoma cells in vitro and significantly suppressed intrahepatic tumor growth and metastasis, and was associated with increased CD3+ lymphocyte infiltration into the tumors. Conclusion: These findings suggest that immunization with ASPH-loaded DCs may constitute a novel therapeutic approach for intrahepatic cholangiocarcinoma, because this protein also appears to be highly conserved and expressed on human hepatobiliary tumors. (HEPATOLOGY 2012;55:86–97)

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