Hypothesis on the possible relevance of the immunogenic cell death in the treatment of gestational trophoblastic neoplasms.

The genetic background and the antigenic landscape of cancer cells play a critical role in the response to immunotherapies. A high tumor antigenicity, together with an increased adjuvanticity potentially induced by a peculiar type of cell death, namely immunogenic cell death (ICD), could foster the response to immunogenic therapies. The gestational trophoblastic neoplasm (GTN) is a one-of-a-kind cancer in the oncological landscape due to its exclusive genomic makeup. The prognosis of GTN is significantly better than non-gestational trophoblastic neoplasm (nGTN). Due to its peculiar genetic inheritance, GTN potentially constitutes a singular archetype in the immuno-oncological field.

High-Throughput Quantification of GFP-LC3+ Dots by Automated Fluorescence Microscopy.

Macroautophagy is a specific variant of autophagy that involves a dedicated double-membraned organelle commonly known as autophagosome. Various methods have been developed to quantify the size of the autophagosomal compartment, which is an indirect indicator of macroautophagic responses, based on the peculiar ability of microtubule-associated protein 1 light chain 3 beta (MAP1LC3B; best known as LC3) to accumulate in forming autophagosomes upon maturation. One particularly convenient method to monitor the accumulation of mature LC3 within autophagosomes relies on a green fluorescent protein (GFP)-tagged variant of this protein and fluorescence microscopy. In physiological conditions, cells transfected temporarily or stably with a GFP-LC3-encoding construct exhibit a diffuse green fluorescence over the cytoplasm and nucleus. Conversely, in response to macroautophagy-promoting stimuli, the GFP-LC3 signal becomes punctate and often (but not always) predominantly cytoplasmic. The accumulation of GFP-LC3 in cytoplasmic dots, however, also ensues the blockage of any of the steps that ensure the degradation of mature autophagosomes, calling for the implementation of strategies that accurately discriminate between an increase in autophagic flux and an arrest in autophagic degradation. Various cell lines have been engineered to stably express GFP-LC3, which-combined with the appropriate controls of flux, high-throughput imaging stations, and automated image analysis-offer a relatively straightforward tool to screen large chemical or biological libraries for inducers or inhibitors of autophagy. Here, we describe a simple and robust method for the high-throughput quantification of GFP-LC3+ dots by automated fluorescence microscopy.

Automated Analysis of Fluorescence Colocalization: Application to Mitophagy.

Mitophagy is a peculiar form of organelle-specific autophagy that targets mitochondria. This process ensures cellular homeostasis, as it fosters the disposal of aged and damaged mitochondria that otherwise would be prone to produce reactive oxygen species and hence endanger genomic stability. Similarly, autophagic clearance of depolarized mitochondria plays a fundamental role in organismal homeostasis as exemplified by the link between Parkinson disease and impaired function of the mitophagy-mediating proteins PINK1 and Parkin. Here, we detail an image-based approach for the quantification of mitochondrial Parkin translocation, which is mechanistically important for the initiation of mitophagy.

The oncolytic peptide LTX-315 triggers immunogenic cell death.

LTX-315 is a cationic amphilytic peptide that preferentially permeabilizes mitochondrial membranes, thereby causing partially BAX/BAK1-regulated, caspase-independent necrosis. Based on the observation that intratumorally injected LTX-315 stimulates a strong T lymphocyte-mediated anticancer immune response, we investigated whether LTX-315 may elicit the hallmarks of immunogenic cell death (ICD), namely (i) exposure of calreticulin on the plasma membrane surface, (ii) release of ATP into the extracellular space, (iii) exodus of HMGB1 from the nucleus, and (iv) induction of a type-1 interferon response. Using a panel of biosensor cell lines and robotized fluorescence microscopy coupled to automatic image analysis, we observed that LTX-315 induces all known ICD characteristics. This conclusion was validated by several independent methods including immunofluorescence stainings (for calreticulin), bioluminescence assays (for ATP), immunoassays (for HMGB1), and RT-PCRs (for type-1 interferon induction). When injected into established cancers, LTX-315 caused a transiently hemorrhagic focal necrosis that was accompanied by massive release of HMGB1 (from close-to-all cancer cells), as well as caspase-3 activation in a fraction of the cells. LTX-315 was at least as efficient as the positive control, the anthracycline mitoxantrone (MTX), in inducing local inflammation with infiltration by myeloid cells and T lymphocytes. Collectively, these results support the idea that LTX-315 can induce ICD, hence explaining its capacity to mediate immune-dependent therapeutic effects.

Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition.

Correction to: Oncogene (2015) 34, 1475­1486; doi:10.1038/ onc.2014.96; published online 14 April 2014 .The authors wish to amend the wording of the following sentence on page 2, replacing 'intracellular acidification' with 'intracellular alkalinization'

A long non-coding RNA links calreticulin-mediated immunogenic cell removal to RB1 transcription.

A subset of promoters bidirectionally expresses long non-coding RNAs (ncRNAs) of unknown function and protein-coding genes (PCGs) in parallel. Here, we define a set of 1107 highly conserved human bidirectional promoters that mediate the linked expression of long ncRNAs and PCGs. Depletion of the long ncRNA expressed from the RB1 promoter, ncRNA-RB1, reveals regulatory effects different from the RB1-controlled transcriptional program. ncRNA-RB1 positively regulates the expression of calreticulin (CALR) that in response to certain therapeutic interventions can translocate from the endoplasmic reticulum to the cell surface, hence activating anticancer immune responses. Knockdown of ncRNA-RB1 in tumor cells reduced expression of CALR, impaired the translocation of the protein to the cell surface upon treatment with anthracylines and consequently inhibited the cellular uptake by macrophages. In conclusion, co-transcription of ncRNA-RB1 and RB1 provides a positive link between the expression of the two tumor suppressors RB1 and the immune-relevant CALR protein. This regulatory interplay exemplifies disease-relevant co-regulation of two distinct gene products, in which loss of expression of one oncosuppressor protein entails the abolition of additional tumor-inhibitory mechanisms.

Immune-dependent antineoplastic effects of cisplatin plus pyridoxine in non-small-cell lung cancer.

cis-Diamminedichloroplatinum(II) (CDDP), which is mostly referred to as cisplatin, is a widely used antineoplastic. The efficacy of cisplatin can be improved by combining it with the vitamin B6 precursor pyridoxine. Here, we evaluated the putative synergistic interaction of CDDP with pyridoxine in the treatment of an orthotopic mouse model of non-small-cell lung cancer (NSCLC). CDDP and pyridoxine exhibited hyperadditive therapeutic effects. However, this synergy was only observed in the context of an intact immune system and disappeared when the otherwise successful drug combination was applied to the same NSCLC cancer implanted in the lungs of athymic mice (which lack T lymphocytes). Immunocompetent mice that had been cured from NSCLC by the combined regimen of CDDP plus pyridoxine became resistant against subcutaneous rechallenge with the same (but not with an unrelated) cancer cell line. In vitro, CDDP and pyridoxine did not only cause synergistic killing of NSCLC cells but also elicited signs of immunogenic cell death including an endoplasmic reticulum stress response and exposure of calreticulin at the surface of the NSCLC cells. NSCLC cells treated with CDDP plus pyridoxine in vitro elicited a protective anticancer immune response upon their injection into immunocompetent mice. Altogether, these results suggest that the combined regimen of cisplatin plus pyridoxine mediates immune-dependent antineoplastic effects against NSCLC.

Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition.

The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.

Autophagy inhibition radiosensitizes in vitro, yet reduces radioresponses in vivo due to deficient immunogenic signalling.

Clinical oncology heavily relies on the use of radiotherapy, which often leads to merely transient responses that are followed by local or distant relapse. The molecular mechanisms explaining radioresistance are largely elusive. Here, we identified a dual role of autophagy in the response of cancer cells to ionizing radiation. On one hand, we observed that the depletion of essential autophagy-relevant gene products, such as ATG5 and Beclin 1, increased the sensitivity of human or mouse cancer cell lines to irradiation, both in vitro (where autophagy inhibition increased radiation-induced cell death and decreased clonogenic survival) and in vivo, after transplantation of the cell lines into immunodeficient mice (where autophagy inhibition potentiated the tumour growth-inhibitory effect of radiotherapy). On the other hand, when tumour proficient or deficient for autophagy were implanted in immunocompetent mice, it turned out that defective autophagy reduced the efficacy of radiotherapy. Indeed, radiotherapy elicited an anti-cancer immune response that was dependent on autophagy-induced ATP release from stressed or dying tumour cells and was characterized by dense lymphocyte infiltration of the tumour bed. Intratumoural injection of an ecto-ATPase inhibitor restored the immune infiltration of autophagy-deficient tumours post radiotherapy and improved the growth-inhibitory effect of ionizing irradiation. Altogether, our results reveal that beyond its cytoprotective function, autophagy confers immunogenic properties to tumours, hence amplifying the efficacy of radiotherapy in an immunocompetent context. This has far-reaching implications for the development of pharmacological radiosensitizers.

Immunogenic calreticulin exposure occurs through a phylogenetically conserved stress pathway involving the chemokine CXCL8.

The exposure of calreticulin (CRT) on the surface of stressed and dying cancer cells facilitates their uptake by dendritic cells and the subsequent presentation of tumor-associated antigens to T lymphocytes, hence stimulating an anticancer immune response. The chemotherapeutic agent mitoxantrone (MTX) can stimulate the peripheral relocation of CRT in both human and yeast cells, suggesting that the CRT exposure pathway is phylogenetically conserved. Here, we show that pheromones can act as physiological inducers of CRT exposure in yeast cells, thereby facilitating the formation of mating conjugates, and that a large-spectrum inhibitor of G protein-coupled receptors (which resemble the yeast pheromone receptor) prevents CRT exposure in human cancer cells exposed to MTX. An RNA interference screen as well as transcriptome analyses revealed that chemokines, in particular human CXCL8 (best known as interleukin-8) and its mouse ortholog Cxcl2, are involved in the immunogenic translocation of CRT to the outer leaflet of the plasma membrane. MTX stimulated the production of CXCL8 by human cancer cells in vitro and that of Cxcl2 by murine tumors in vivo. The knockdown of CXCL8/Cxcl2 receptors (CXCR1/Cxcr1 and Cxcr2) reduced MTX-induced CRT exposure in both human and murine cancer cells, as well as the capacity of the latter-on exposure to MTX-to elicit an anticancer immune response in vivo. Conversely, the addition of exogenous Cxcl2 increased the immunogenicity of dying cells in a CRT-dependent manner. Altogether, these results identify autocrine and paracrine chemokine signaling circuitries that modulate CRT exposure and the immunogenicity of cell death.

Molecular mechanisms of ATP secretion during immunogenic cell death.

The immunogenic demise of cancer cells can be induced by various chemotherapeutics, such as anthracyclines and oxaliplatin, and provokes an immune response against tumor-associated antigens. Thus, immunogenic cell death (ICD)-inducing antineoplastic agents stimulate a tumor-specific immune response that determines the long-term success of therapy. The release of ATP from dying cells constitutes one of the three major hallmarks of ICD and occurs independently of the two others, namely, the pre-apoptotic exposure of calreticulin on the cell surface and the postmortem release of high-mobility group box 1 (HMBG1) into the extracellular space. Pre-mortem autophagy is known to be required for the ICD-associated secretion of ATP, implying that autophagy-deficient cancer cells fail to elicit therapy-relevant immune responses in vivo. However, the precise molecular mechanisms whereby ATP is actively secreted in the course of ICD remain elusive. Using a combination of pharmacological screens, silencing experiments and techniques to monitor the subcellular localization of ATP, we show here that, in response to ICD inducers, ATP redistributes from lysosomes to autolysosomes and is secreted by a mechanism that requires the lysosomal protein LAMP1, which translocates to the plasma membrane in a strictly caspase-dependent manner. The secretion of ATP additionally involves the caspase-dependent activation of Rho-associated, coiled-coil containing protein kinase 1 (ROCK1)-mediated, myosin II-dependent cellular blebbing, as well as the opening of pannexin 1 (PANX1) channels, which is also triggered by caspases. Of note, although autophagy and LAMP1 fail to influence PANX1 channel opening, PANX1 is required for the ICD-associated translocation of LAMP1 to the plasma membrane. Altogether, these findings suggest that caspase- and PANX1-dependent lysosomal exocytosis has an essential role in ATP release as triggered by immunogenic chemotherapy.

Characterization of novel MPS1 inhibitors with preclinical anticancer activity.

Monopolar spindle 1 (MPS1), a mitotic kinase that is overexpressed in several human cancers, contributes to the alignment of chromosomes to the metaphase plate as well as to the execution of the spindle assembly checkpoint (SAC). Here, we report the identification and functional characterization of three novel inhibitors of MPS1 of two independent structural classes, N-(4-{2-[(2-cyanophenyl)amino][1,2,4]triazolo[1,5-a]pyridin-6-yl}phenyl)-2-phenylacetamide (Mps-BAY1) (a triazolopyridine), N-cyclopropyl-4-{8-[(2-methylpropyl)amino]-6-(quinolin-5-yl)imidazo[1,2-a]pyrazin-3-yl}benzamide (Mps-BAY2a) and N-cyclopropyl-4-{8-(isobutylamino)imidazo[1,2-a]pyrazin-3-yl}benzamide (Mps-BAY2b) (two imidazopyrazines). By selectively inactivating MPS1, these small inhibitors can arrest the proliferation of cancer cells, causing their polyploidization and/or their demise. Cancer cells treated with Mps-BAY1 or Mps-BAY2a manifested multiple signs of mitotic perturbation including inefficient chromosomal congression during metaphase, unscheduled SAC inactivation and severe anaphase defects. Videomicroscopic cell fate profiling of histone 2B-green fluorescent protein-expressing cells revealed the capacity of MPS1 inhibitors to subvert the correct timing of mitosis as they induce a premature anaphase entry in the context of misaligned metaphase plates. Hence, in the presence of MPS1 inhibitors, cells either divided in a bipolar (but often asymmetric) manner or entered one or more rounds of abortive mitoses, generating gross aneuploidy and polyploidy, respectively. In both cases, cells ultimately succumbed to the mitotic catastrophe-induced activation of the mitochondrial pathway of apoptosis. Of note, low doses of MPS1 inhibitors and paclitaxel (a microtubular poison) synergized at increasing the frequency of chromosome misalignments and missegregations in the context of SAC inactivation. This resulted in massive polyploidization followed by the activation of mitotic catastrophe. A synergistic interaction between paclitaxel and MPS1 inhibitors could also be demonstrated in vivo, as the combination of these agents efficiently reduced the growth of tumor xenografts and exerted superior antineoplastic effects compared with either compound employed alone. Altogether, these results suggest that MPS1 inhibitors may exert robust anticancer activity, either as standalone therapeutic interventions or combined with microtubule-targeting chemicals.

Effects of vitamin B6 metabolism on oncogenesis, tumor progression and therapeutic responses.

Pyridoxal-5'-phosphate (PLP), the bioactive form of vitamin B6, reportedly functions as a prosthetic group for >4% of classified enzymatic activities of the cell. It is therefore not surprising that alterations of vitamin B6 metabolism have been associated with multiple human diseases. As a striking example, mutations in the gene coding for antiquitin, an evolutionary old aldehyde dehydrogenase, result in pyridoxine-dependent seizures, owing to the accumulation of a metabolic intermediate that inactivates PLP. In addition, PLP is required for the catabolism of homocysteine by transsulfuration. Hence, reduced circulating levels of B6 vitamers (including PLP as well as its major precursor pyridoxine) are frequently paralleled by hyperhomocysteinemia, a condition that has been associated with an increased risk for multiple cardiovascular diseases. During the past 30 years, an intense wave of clinical investigation has attempted to dissect the putative links between vitamin B6 and cancer. Thus, high circulating levels of vitamin B6, as such or as they reflected reduced amounts of circulating homocysteine, have been associated with improved disease outcome in patients bearing a wide range of hematological and solid neoplasms. More recently, the proficiency of vitamin B6 metabolism has been shown to modulate the adaptive response of tumor cells to a plethora of physical and chemical stress conditions. Moreover, elevated levels of pyridoxal kinase (PDXK), the enzyme that converts pyridoxine and other vitamin B6 precursors into PLP, have been shown to constitute a good, therapy-independent prognostic marker in patients affected by non-small cell lung carcinoma (NSCLC). Here, we will discuss the clinical relevance of vitamin B6 metabolism as a prognostic factor in cancer patients.

Caspase-3 and prostaglandins signal for tumor regrowth in cancer therapy.

Chemo- and radio-therapeutic regimens frequently kill cancer cells by inducing apoptosis, a cell-death subroutine that involves the activation of a particular class of proteases called caspases. In a recent issue of Nature Medicine, Huang et al. (2011) show that caspase activation in dying tumor cells causes the release of soluble lipid messengers, notably prostaglandin E(2), that stimulate tumor cell proliferation. In this short review, we will discuss the clinical and therapeutic implications of these findings.

Antineoplastic activity of ouabain and pyrithione zinc in acute myeloid leukemia.

Despite recent progress in the treatment of acute myeloid leukemia (AML), the prognosis of this rather heterogeneous disease remains poor and novel chemotherapeutics that specifically target leukemic cells must be developed. To address this need at the preclinical level, we implemented a high content imaging-based screen for the identification of small agents that induce AML cell death in vitro. Among a panel of 1040 Food and Drug Administration-approved agents, we identified pyrithione zinc (PZ) and ouabain (OUA) as potential antileukemic compounds. Both PZ and OUA efficiently induced cell death associated with apoptotic chromatin condensation and inhibition of nuclear factor-κB survival signaling, leading to reduced expression of antiapoptotic proteins, in several AML cell lines. PZ- and OUA-induced cell death was associated with the permeabilization of the outer mitochondrial membrane and led to the release of cytochrome c followed by caspase activation. Both PZ and OUA exerted significant anticancer effects in vivo, on human AML cells xenografts as well as ex vivo, on CD34(+) (but not CD34(-)) malignant myeloblasts from AML patients. Altogether, our results suggest that PZ and OUA may exhibit antileukemic effects by inducing the apoptotic demise of AML cells.

Molecular mechanisms of cisplatin resistance.

Platinum-based drugs, and in particular cis-diamminedichloroplatinum(II) (best known as cisplatin), are employed for the treatment of a wide array of solid malignancies, including testicular, ovarian, head and neck, colorectal, bladder and lung cancers. Cisplatin exerts anticancer effects via multiple mechanisms, yet its most prominent (and best understood) mode of action involves the generation of DNA lesions followed by the activation of the DNA damage response and the induction of mitochondrial apoptosis. Despite a consistent rate of initial responses, cisplatin treatment often results in the development of chemoresistance, leading to therapeutic failure. An intense research has been conducted during the past 30 years and several mechanisms that account for the cisplatin-resistant phenotype of tumor cells have been described. Here, we provide a systematic discussion of these mechanism by classifying them in alterations (1) that involve steps preceding the binding of cisplatin to DNA (pre-target resistance), (2) that directly relate to DNA-cisplatin adducts (on-target resistance), (3) concerning the lethal signaling pathway(s) elicited by cisplatin-mediated DNA damage (post-target resistance) and (4) affecting molecular circuitries that do not present obvious links with cisplatin-elicited signals (off-target resistance). As in some clinical settings cisplatin constitutes the major therapeutic option, the development of chemosensitization strategies constitute a goal with important clinical implications.

Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012.

In 2009, the Nomenclature Committee on Cell Death (NCCD) proposed a set of recommendations for the definition of distinct cell death morphologies and for the appropriate use of cell death-related terminology, including 'apoptosis', 'necrosis' and 'mitotic catastrophe'. In view of the substantial progress in the biochemical and genetic exploration of cell death, time has come to switch from morphological to molecular definitions of cell death modalities. Here we propose a functional classification of cell death subroutines that applies to both in vitro and in vivo settings and includes extrinsic apoptosis, caspase-dependent or -independent intrinsic apoptosis, regulated necrosis, autophagic cell death and mitotic catastrophe. Moreover, we discuss the utility of expressions indicating additional cell death modalities. On the basis of the new, revised NCCD classification, cell death subroutines are defined by a series of precise, measurable biochemical features.

Association and dissociation of autophagy, apoptosis and necrosis by systematic chemical study.

To address the question of whether established or experimental anticancer chemotherapeutics can exert their cytotoxic effects by autophagy, we performed a high-content screen on a set of cytotoxic agents. We simultaneously determined parameters of autophagy, apoptosis and necrosis on cells exposed to -1400 compounds. Many agents induced a 'pure' autophagic, apoptotic or necrotic phenotype, whereas less than 100 simultaneously induced autophagy, apoptosis and necrosis. A systematic analysis of the autophagic flux induced by the most potent 80 inducers of GFP-LC3 puncta among the NCI panel agents showed that 59 among them truly induced autophagy. The remaining 21 compounds were potent inducers of apoptosis or necrosis, yet failed to stimulate an autophagic flux, which were characterized as microtubule inhibitors. Knockdown of ATG7 was efficient in preventing GFP-LC3 puncta, yet failed to attenuate cell death by the agents that induce GFP-LC3 puncta. Thus there is not a single compound that would induce cell death by autophagy in our screening, underscoring the idea that cell death is rarely, if ever, executed by autophagy in human cells.

Magnitude of the Root effect in red blood cells and haemoglobin solutions of fishes: a tribute to August Krogh.

AIM: The ability of high carbon dioxide tensions or low pH to reduce blood oxygen binding even at high oxygen tensions, first observed by August Krogh and Isabella Leitch in 1919 and now known as the Root effect, was studied in red blood cells and haemoglobin solutions of several fish species. METHODS: Red blood cells in physiological saline were acidified at atmospheric oxygen tension by increasing carbon dioxide tensions and the percentage decrease in oxygen content was used to quantify the Root effect. Haemoglobin was incubated in air-equilibrated citrate buffers between pH 5 and 7 and the percentage decrease in oxygen saturation relative to pH 8 determined by spectral deconvolution. RESULTS: The maximal magnitude of the Root effect in citrate-buffered haemoglobin solutions closely matched the value in blood or red blood cells of 11 vertebrates over a Root effect range between 3 and 80%. Contrary to previous reports, there was no evidence for a significant Root effect in red blood cells or haemoglobin solutions of the wels catfish, but a significant Root effect under both conditions in the Siberian sturgeon. CONCLUSIONS: Under the conditions employed in this study, the maximal Root effect of citrate-buffered haemoglobin solutions closely resembles the maximal Root effect in red blood cells. This strengthens previous studies on the evolution of the Root effect and its role in oxygen concentration at the retina and swimbladder of a large number of fishes that were based on Root effect measurements in haemoglobin solutions.

Restoration of the immunogenicity of cisplatin-induced cancer cell death by endoplasmic reticulum stress.

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 2α (eIF2α). Accordingly, CDDP also failed to stimulate the formation of stress granules and macroautophagy, two processes that only occur after eIF2α 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+)-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.