title: Generation of antigen-presenting cells from tumor-infiltrated CD11b myeloid cells with DNA demethylating agent 5-aza-2'-deoxycytidine.
abstract: Tumor-recruited CD11b myeloid cells, including myeloid-derived suppressor cells, play a significant role in tumor progression, as these cells are involved in tumor-induced immune suppression and tumor neovasculogenesis. On the other hand, the tumor-infiltrated CD11b myeloid cells could potentially be a source of immunostimulatory antigen-presenting cells (APCs), since most of these cells represent common precursors of both dendritic cells and macrophages. Here, we investigated the possibility of generating mature APCs from tumor-infiltrated CD11b myeloid cells. We demonstrate that in vitro exposure of freshly excised mouse tumors to DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (decitabine, AZA) results in selective elimination of tumor cells, but, surprisingly it also enriches CD45(+) tumor-infiltrated cells. The majority of "post-AZA" surviving CD45(+) tumor-infiltrated cells were represented by CD11b myeloid cells. A culture of isolated tumor-infiltrated CD11b cells in the presence of AZA and GM-CSF promoted their differentiation into mature F4/80/CD11c/MHC class II-positive APCs. These tumor-derived myeloid APCs produced substantially reduced amounts of immunosuppressive (IL-13, IL-10, PGE(2)), pro-angiogenic (VEGF, MMP-9) and pro-inflammatory (IL-1beta, IL-6, MIP-2) mediators than their precursors, freshly isolated tumor-infiltrated CD11b cells. Vaccinating naïve mice with ex vivo generated tumor-derived APCs resulted in the protection of 70% mice from tumor outgrowth. Importantly, no loading of tumor-derived APC with exogenous antigen was needed to stimulate T cell response and induce the anti-tumor effect. Collectively, our results for the first time demonstrate that tumor-infiltrated CD11b myeloid cells can be enriched and differentiated in the presence of DNA demethylating agent 5-aza-2'-deoxycytidine into mature tumor-derived APCs, which could be used for cancer immunotherapy.
authors.affiliation: Department of Urology, Shands Cancer Center, University of Florida, Gainesville, 32610, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Daurkin
authors.forename: Evgeniy
authors.initials: E
authors.lastname: Eruslanov
authors.forename: Johannes
authors.initials: J
authors.lastname: Vieweg
authors.forename: Sergei
authors.initials: S
authors.lastname: Kusmartsev
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000187:drug effects* / Q000637:transplantation; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D015153:Blotting, Western; D039481:CD11b Antigen / Q000378:metabolism; D019496:Cancer Vaccines / Q000276:immunology / Q000627:therapeutic use; D002454:Cell Differentiation / Q000187:drug effects* / Q000276:immunology; D002469:Cell Separation; D016207:Cytokines / Q000096:biosynthesis; D000077209:Decitabine; D005260:Female; D005434:Flow Cytometry; D007167:Immunotherapy / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D022423:Myeloid Cells / Q000166:cytology / Q000187:drug effects* / Q000637:transplantation; D009374:Neoplasms, Experimental / Q000628:therapy; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000964:Antimetabolites, Antineoplastic; D039481:CD11b Antigen; D019496:Cancer Vaccines; D016207:Cytokines; D000077209:Decitabine; D001374:Azacitidine