Influence of drug‐induced apoptotic death on processing and presentation of tumor antigens by dendritic cells

Abstract

Here we have studied the effects of apoptotic cell death induced by chemotherapic agents on tumor phagocytosis by dendritic cells (DC) and presentation of the relevant antigen to T lymphocytes. Annexin-V-FITC (Ann-V) and propidium iodide (PI) staining was used to assess early apoptotic (Ann-V ؉ /PI ؊ ) vs. late apoptotic/secondary necrotic (Ann-V ؉ /PI ؉ ) death after a 24 hr observation of untreated and drug-treated gastric carcinoma cells. After treatments, the HLA-A*0201 ؉ tumor cell line KATO III was exposed for 24 hr to allogeneic, HLA-related GM-CSF, IL-4-driven immature (i) DC. Tumorloaded iDC were tested for IL-12 release in an ELISA assay, incubated with the DC-maturating factor TNF-␣ and used as stimulators for autologous T lymphocytes. Generation of antitumor T response against KATO cells was evaluated in an anti-MHC class I MAb-blocked Interferon-␥ ELISPOT assay. After treatment with Cis-platin (cis), all dying cells were in early apoptosis, whereas secondary necrosis was the prevalent death pattern observed after epirubicin (epi) and doxorubicin (doxo). Doxo and epi increased tumor expression of heat shock protein (hsp) 70 and uptake of tumor cell components by DC, whereas cis treatment had no effect on hsp70 and was associated with poor tumor uptake by DC. Significant upmodulation of IL-12 was observed by DC that had taken up the doxo-and epi-treated tumors (p< 0.005 and p< 0.01, respectively). Increased IFN-␥ release was also observed after stimulation of T lymphocytes with DC loaded with doxo-and epi-treated (p< 0.02 and p< 0.005, respectively) but not with cis-treated DC. These data show that the products of early apoptosis cannot efficiently cross-activate MHC class I-restricted anti-tumor lymphocytes even in the presence of DC maturating factors, whereas secondary necrosis is associated with robust T cell response.

Immune-based mechanisms of cytotoxic chemotherapy: implications for the design of novel and rationale-based combined treatments against cancer

“…Pioneering studies showed that 5-FU and doxorubicin induced in vitro cancer expression of heat shock proteins (HSPs) that promote the engulfment of cell debris by human DCs and the subsequent crosspresentation of tumor antigens to T-cells. 29,30 More recently, Casares et al 31 showed that doxorubicin-killed tumor cells elicit tumor-specific immune responses when injected into syngeneic mice, by stimulating DC phagocytosis and CD8 T-cell responses. Subsequent work from L. Zitvogel's laboratory identified the molecular mechanism linking immunogenic apoptosis induced by chemotherapy to DC activation, as detailed below.…”

Differential mechanisms of microparticle transfer toB cells and monocytes: anti‐inflammatory propertiesof microparticles

“…To induce apoptosis in Kato cells, we incubated the cells for 24 h with 100 lg/mL cisplatin according to a protocol established by Buttiglieri et al [45]. The nonadherent apoptotic Kato cells were recovered and washed three times to remove the cisplatin, and approximately 500 000 apoptotic Kato cells were incubated with 100 000 monocytes or 50 000 B cells.…”

Dendritic Cells in Drug-induced Toxicity

“…Similar to the inflammatory response to pathogens, sterile inflammation is marked by apoptosis and/or necrosis of an enormous number of cells in different organs and tissues [1]. These dead or dying cells release a large repertoire of endogenous ligands, such as nucleic acids, heat shock proteins, uric acid and intracellular proteins, which can bind to pattern recognition receptors on leukocytes, particularly those on dendritic cells and macrophages, and initiate inflammation, tissue injury and adaptive immune responses [3][4][5][6][7][8]. In infections, the inflammatory response is usually limited because the microbes are often rapidly cleared by humoral and/or cellular immune mechanisms.…”

“…This forms the basis for the induction of peripheral tolerance, which is required in addition to the central tolerance acquired during the early days of development of the immune system. In response to pathogens or products of tissue injury, the DCs in tissues undergo maturation and increase their expression of antigen presentation and co-stimulatory molecules and production of cytokines and chemokines, which are required to initiate inflammatory innate or adaptive immune responses [3,4,6,17].…”