In contrast to other cytotoxic agents including anthracyclins and oxaliplatin (OXP), cisplatin (CDDP) fails to induce immunogenic tumor cell death that would allow to stimulate an anticancer immune response and hence to amplify its therapeutic efficacy. This failure to induce immunogenic cell death can be attributed to CDDP's incapacity to elicit the translocation of calreticulin (CRT) from the lumen of the endoplasmic reticulum (ER) to the cell surface. Here, we show that, in contrast to OXP, CDDP is unable to activate the protein kinase-like ER kinase (PERK)-dependent phosphorylation of the eukaryotic translation initiation factor 2a (eIF2a). Accordingly, CDDP also failed to stimulate the formation of stress granules and macroautophagy, two processes that only occur after eIF2a phosphorylation. Using a screening method that monitors the voyage of CRT from the ER lumen to the cell surface, we identified thapsigargin (THAPS), an inhibitor of the sarco/ER Ca 2 þ -ATPase as a molecule that on its own does not stimulate CRT exposure, yet endows CDDP with the capacity to do so. The combination of ER stress inducers (such as THAPS or tunicamycin) and CDDP effectively induced the translocation of CRT to the plasma membrane, as well as immunogenic cell death, although ER stress or CDDP alone was insufficient to induce CRT exposure and immunogenic cell death. Altogether, our results underscore the contribution of the ER stress response to the immunogenicity of cell death.

Macrophage dysfunction plays a pivotal role during neovascular proliferation in diseases of ageing including cancers, atherosclerosis and blinding eye disease. In the eye, choroidal neovascularization (CNV) causes blindness in patients with age-related macular degeneration (AMD). Here we report that increased IL10, not IL4 or IL13, in senescent eyes activates STAT3 signalling that induces the alternative activation of macrophages and vascular proliferation. Targeted inhibition of both IL10 receptor-mediated signalling and STAT3 activation in macrophages reverses the ageing phenotype. In addition, adoptive transfer of STAT3-deficient macrophages into eyes of old mice significantly reduces the amount of CNV. Systemic and CD163+ eye macrophages obtained from AMD patients also demonstrate STAT3 activation. Our studies demonstrate that impaired SOCS3 feedback leads to permissive IL10/STAT3 signalling that promotes alternative macrophage activation and pathological neovascularization. These findings have significant implications for our understanding of the pathobiology of age-associated diseases and may guide targeted immunotherapy.