Supplementary MaterialsSupplementary data. transgenic CD8 T CUDC-305 (DEBIO-0932 ) cells or activated NK cells. Immunogenic cell death was studied analyzing the membrane exposure of calreticulin and the release of high mobility group box 1 (HMGB1) by the dying tumor cells. Furthermore, the potential CUDC-305 (DEBIO-0932 ) immunogenicity of the tumor cell debris was evaluated in immunocompetent mice challenged with an unrelated tumor sharing only one tumor-associated antigen and by class I major histocompatibility complex (MHC)-multimer stainings. Mice deficient in and were used to study mechanistic requirements. Results We observe in cocultures of tumor cells and effector cytotoxic cells, the presence of markers of immunogenic cell death such as calreticulin exposure and soluble HMGB1 protein. Ovalbumin (OVA)-transfected MC38 colon cancer cells, exogenously pulsed to present the gp100 epitope are killed in culture by mouse gp100-specific TCR transgenic CD8 T cells. Immunization of mice with the resulting destroyed cells induces epitope spreading as observed by detection of OVA-specific T cells by MHC multimer staining and rejection of OVA+ EG7 lymphoma cells. Similar results were observed in mice immunized with cell debris generated by NK-cell mediated cytotoxicity. Mice deficient in (Batf3KO), (STINGKO), interferon-((IFNARKO), (RAG1), (Pmel-1),24 C57BL/6-(OT-I), C57Bl/6 (OT-I-enhanced green fluorescent protein (EGFP)) mice were bred at Cima Universidad de Navarra in specific pathogen-free conditions. KO,25 KO26 and KO27 mice were kindly provided, respectively, by Kenneth M Murphy (Washington University, St. Louis, MO), by Gloria Gonzlez Aseguinolaza (Cima Universidad de Navarra, Pamplona, Spain) and by Matthew Albert (Institut Pasteur, Paris, France). The MC38hEGFR cell line was kindly provided by Pablo Uma?a (Roche). This cell line was stably transfected with Lipofectamine 2000 (Thermo Fisher Scientific, San Jose, California, USA) with pCI-neo plasmid expressing membrane-bound ovalbumin (OVA) (#25099, Addgene, Cambridge, Massachusetts, USA). MC38hEGFROVA clones were established by limiting dilution. MC38hEGFROVA was chosen because of suitability for ADCC experiments and convenience for detection but control replicate experiments to those shown in figure 1 with MC38OVA without EGFR were performed rendering comparable results. OVA expression was confirmed by intracellular OVA staining (ab85584, Abcam, Cambridge, UK) and real-time PCR. The MC38hEGFROVA, EG7, MC38, B16OVA, CHO FLT3-L FLAG cell lines were maintained at 37C in 5% CO2 and were grown in Roswell Park Memorial Institute medium (RPMI) Medium 1640+Glutamax (Gibco Invitrogen, Carlsbad, California, USA) containing 10% heat-inactivated fetal bovine serum (FBS) (Gibco), 100 IU/mL penicillin and 100 g/mL streptomycin (Gibco) and 50 M 2-Mercaptoethanol (Gibco). The MC38hEGFROVA cell line was grown with 6 g/mL of Puromycin (Gibco) and 400 g/mL of Geneticin (Gibco). To avoid loss of transgene expression, B16OVA and EG7 were maintained with 400 g/mL of Geneticin. Open in a separate window Figure 1 Cellular cytotoxicity induces the release of danger-associated molecular patterns by dying cancer cells in culture. (A) MC38hEGFROVA CUDC-305 (DEBIO-0932 ) cells were incubated for 48 hours with IFN (15 UI/mL) and gp100 peptide (100 ng/mL). Subsequently, in vitro preactivated Pmel-1-derived splenocytes were added at a ratio of 10:1. calreticulin surface expression on dying tumor cells (CD45- 7-AAD-) was analyzed after 24 CUDC-305 (DEBIO-0932 ) hours by flow cytometry. Representative experiments are presented in dot plots and histograms indicating MFI. (B) Supernatants from the cocultures were analyzed for the concentration of HMGB1 by ELISA. As controls, tumor cells, or T cells with or without pulsed peptide were used. Data are meanSEM n=4 for coculture with peptide and n=5 for other groups (C) MC38hEGFROVA cells were incubated with in vivo activated NK cells at CUDC-305 (DEBIO-0932 ) a ratio of 3.5:1 for 24 hours. Subsequently, calreticulin surface expression on dying tumor cells (CD45- 7-AAD-) was analyzed by flow cytometry. Representative experiments are presented in dot plots and histograms indicating MFI. (D) HMGB1 concentrations in the supernatant were determined by ELISA. As controls, tumor cells or NK cells alone Rabbit polyclonal to Neurogenin2 were used. Data are meanSEM n=5 for all groups. One-way ANOVA test with Tukeys multiple comparisons tests, ***p 0.001. Results are representative of at least two experiments performed. ANOVA, analysis of variance; HMGB1, high mobility group box 1;.