PDF file - 270KB, Supplementary Figure S1. Phenotype of in vitro generated mDCs. Supplementary Figure S2. Efficiency of transfection. Supplementary Figure S3. HuHuT-, HuRT- and RHuT-DCs from HS elicit anti-HER2 CD8 response. Supplementary Figure S4. RHuT-DCs from HER2-CP elicit anti-HER2 CD8 T cell response. Supplementary Figure S5. HuHuT DCs affects Treg cells activity. Supplementary Figure S6. HuHuT-DCs activate CD8 and CD4 T cells from CTRL-CP. Supplementary Table S1. HER2-overexpressing cancer patients. Supplementary Table S2. HER2-negative cancer patients.
ARTICLE ABSTRACT
Purpose: Despite the great success of HER2 vaccine strategies in animal models, effective clinical results have not yet been obtained. We studied the feasibility of using DNA coding for chimeric rat/human HER2 as a tool to break the unresponsiveness of T cells from patients with HER2-overexpressing tumors (HER2-CP).Experimental Design: Dendritic cells (DCs) generated from patients with HER2-overexpressing breast (n = 28) and pancreatic (n = 16) cancer were transfected with DNA plasmids that express human HER2 or heterologous rat sequences in separate plasmids or as chimeric constructs encoding rat/human HER2 fusion proteins and used to activate autologous T cells. Activation was evaluated by IFN-γ ELISPOT assay, perforin expression, and ability to halt HER2+ tumor growth in vivo.Results: Specific sustained proliferation and IFN-γ production by CD4 and CD8 T cells from HER2-CP was observed after stimulation with autologous DCs transfected with chimeric rat/human HER2 plasmids. Instead, T cells from healthy donors (n = 22) could be easily stimulated with autologous DCs transfected with any human, rat, or chimeric rat/human HER2 plasmid. Chimeric HER2-transfected DCs from HER2-CP were also able to induce a sustained T-cell response that significantly hindered the in vivo growth of HER2+ tumors. The efficacy of chimeric plasmids in overcoming tumor-induced T-cell dysfunction relies on their ability to circumvent suppressor effects exerted by regulatory T cells (Treg) and/or interleukin (IL)-10 and TGF-β1.Conclusions: These results provide the proof of concept that chimeric rat/human HER2 plasmids can be used as effective vaccines for any HER2-CP with the advantage of being not limited to specific MHC. Clin Cancer Res; 20(11); 2910–21. ©2014 AACR.
