Post-apoptotic tumors are more palatable to dendritic cells and enhance their antigen cross-presentation activity.
Critical issues for cytotoxic lymphocyte (CTL) cross-priming are (a) the maturation state of dendritic cells (DC), (b) the source of the tumor-associated antigens (TAA) and (c) the context in which they are delivered to DCs. Drug-induced apoptosis has recently been implicated in CTL cross-priming. However, since drug-treatment produces in vivo more tumor cells than the DC default apoptotic clearance program can cope with, they are expected to proceed to secondary necrosis and change their molecular pattern. Here we have addressed this issue on renal carcinoma cells (RCC) by using different apoptotic stimuli. UVC, but not gamma-irradiation or anthracyclins, induced after 4h treatment of the RCC cell line K1 a combination of apoptotic (phosphatydilserine and calreticulin plasma membrane mobilization) and necrotic (membrane incompetence) features. Heat shock protein (Hsp)-70 and chromatin-bound high mobility box 1 HMGB1 protein, typical of necrosis, were released during the further 20h and thus made accessible to co-cultured monocyte-derived immature (i) DC. UVC-treated, secondary necrotic RCC cell lines were cross-presented with higher efficiency by cytokine-matured (m) DC than their early apoptotic (i.e. gamma-irradiated) counterpart. Upstream events such as increased tumor uptake, activation of genes involved in the antigen-processing machinery, and increased expression of costimulatory and maturation molecules were also observed after loading iDC with secondary necrotic, but not apoptotic, tumor cells. These data offer a description of the molecular and immunogenic characteristics of post-apoptotic tumors which can be exploited to increase the efficiency of in vivo and ex vivo TAA delivery to the DC cross-presentation pathway.
Brusa
Davide
D
Laboratory of Tumor Immunology, Department of Internal Medicine, University of Turin, Turin, Italy.
Garetto
Stefano
S
Chiorino
Giovanna
G
Scatolini
Maria
M
Migliore
Elisa
E
Camussi
Giovanni
G
Matera
Lina
L
D017951:Antigen Presentation / Q000276:immunology*; D017209:Apoptosis / Q000502:physiology*; D045744:Cell Line, Tumor; D045142:Cross-Priming / Q000276:immunology*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D005434:Flow Cytometry; D024243:HMGB1 Protein / Q000235:genetics / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009369:Neoplasms / Q000276:immunology*; D020411:Oligonucleotide Array Sequence Analysis; D010587:Phagocytosis; D013601:T-Lymphocytes / Q000276:immunology
D024243:HMGB1 Protein; D018840:HSP70 Heat-Shock Proteins