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Dendritic cells (DCs) are the sentinel antigen-presenting cells of the immune system; such that their productive interface with the dying cancer cells is crucial for proper communication of the "non-self" status of cancer cells to the adaptive immune system. Efficiency and the ultimate success of such a communication hinges upon the maturation status of the DCs, attained following their interaction with cancer cells. Immature DCs facilitate tolerance towards cancer cells (observed for many apoptotic inducers) while fully mature DCs can strongly promote anticancer immunity if they secrete the correct combinations of cytokines (observed when DCs interact with cancer cells undergoing immunogenic cell death (ICD)). However, an intermediate population of DC maturation, called semi-mature DCs exists, which can potentiate either tolerogenicity or pro-tumourigenic responses (as happens in the case of certain chemotherapeutics and agents exerting ambivalent immune reactions). Specific combinations of DC phenotypic markers, DC-derived cytokines/chemokines, dying cancer cell-derived danger signals and other less characterized entities (e.g. exosomes) can define the nature and evolution of the DC maturation state. In the present review, we discuss these different maturation states of DCs, how they might be attained and which anticancer agents or cell death modalities (e.g. tolerogenic cell death vs. ICD) may regulate these states. [ABSTRACT FROM AUTHOR]

Abstract: Recently, cytokine-based pro-tumourigenic signalling has been found to play a major role in the immune system's pro-tumourigenic activity. On the other hand, other recent findings have shown that immunogenic cancer cell death triggered by certain anticancer modalities might reset the dysfunctional immune system towards the activation of a long-lasting protective anti-tumour response. Therefore, using inducers of immunogenic cell death (ICD) that can prevent or impede tumour-promoting cytokine signalling is one of the best ways of instigating or restoring efficient anti-tumour immunity. In this review it is discussed, how the different ICD inducers interact with the immune system and influence cytokine-based pro-tumourigenic signalling. We believe that it is crucial to discover or develop new anti-cancer therapeutic modalities that can induce ICD and impede tumour-promoting cytokine signalling. [Copyright &y& Elsevier]

Cancer immunosurvelliance usually leads to formation of cancer cells that have been 'immunoedited' to resist anti-tumor immunity. One of the consequences of immunoediting that is, reduced immunogenicity, is an important roadblock in revival of stable and long-lasting anti-tumor immune responses. Research done during the last decade has shown that emission by the dying cancer cells of immunomodulatory factors or damage-associated molecular patterns (DAMPs), which can act as danger signals, is a critical event in accentuating the immunogenicity of cancer cells, in response to a subset of anticancer treatments. Recent evidence has defined that an apoptotic cell death subroutine and its underlying biochemistry, which has been termed as 'immunogenic cell death (ICD)' or 'immunogenic apoptosis,' is required for the efficient emission of DAMPs and inciting anti-tumor immunity. Here, we review the basic concepts of ICD, like cancer immunogenicity, danger signals, and DAMPs. Moreover, we discuss the emerging molecular links between endoplasmic reticulum (ER) stress, induction of a viral response-like gene expression, danger signals, and anti-tumor immunity. We envisage that along with ER stress-based trafficking of DAMPs (which is a 'short-range communicator' of danger), the accompanying induction of a viral response-like gene expression and the secretion of anti-tumorigenic cytokines may become a crucial signature of ICD induction by anticancer therapy. © 2013 BioFactors, 39(4):355-367, 2013 [ABSTRACT FROM AUTHOR]

The inspection of the mechanisms through which autophagy modulates immunogenic cell death revealed that the autophagic response of cancer cells to reactive oxygen species-dependent endoplasmic reticulum stress suppresses the exposure of calreticulin on the cell surface, the phenotypic maturation of dendritic cells (DCs) as well as their ability to release interleukin-6 and to support the proliferative expansion of (interferon γ-producing) CD4+ and CD8+ T lymphocytes. These findings unveil an unprecedented role for therapy-induced autophagy in suppressing key mechanisms that underlie anticancer immune responses as elicited by immunogenic cell death. [ABSTRACT FROM AUTHOR]