ER stress, autophagy and immunogenic cell death in photodynamic therapy-induced anti-cancer immune responses

Tumours are a form of pseudo-organs with their own microenvironment where the cancer cells nurture a dysfunctional immune environment incapable of inciting anti-tumour immunity. It had been proposed that the only way to counteract such an immune system dysfunction in tumours is by eliciting, therapeutically, a cancer cell death pathway that is accompanied by high immunogenicity and possibly inhibits or reduces the influence of the pro-tumourigenic cytokine signalling. Subsequently, a small and a large-scale screening study as well as several targeted studies found that few, selected anticancer therapeutic regimens are able to induce a promising kind of cancer cell demise called immunogenic cell death (ICD), which can activate the immune system owing to the spatiotemporally defined emission of danger signals.