Consensus guidelines for the detection of immunogenic cell death

Machine learning‑based construction of damage‑associated molecular patterns related score identifies subtypes of pancreatic adenocarcinoma with distinct prognosis

The present study aimed to assess the prognostic significance of Damage-Associated Molecular Pattern (DAMP)-related gene expression in pancreatic adenocarcinoma (PAAD) and to develop a scoring system based on these genes. Consensus clustering was performed on patients with PAAD using data from The Cancer Genome Atlas (TCGA) and Meta-cohort datasets, identifying three distinct clusters: C1 (pro-DAMP), C2 (intermediate) and C3 (anti-DAMP). Differential gene expression analysis between clusters C1 and C3 identified 141 significant genes. Least Absolute Shrinkage and Selection Operator Cox regression was utilized to derive an optimal predictor set, leading to the identification of six hub genes associated with the DAMP status, which were then employed to calculate the DAMPscore. Weighted Gene Co-expression Network Analysis revealed a strong correlation between these eight hub genes and the DAMPscore. The functionality of these hub genes in PAAD was validated using a Cell Counting Kit-8 assay and Transwell assays. The results indicated that patients with PAAD with elevated DAMPscores exhibited significantly reduced survival times. Receiver operating characteristic (ROC) curve analysis indicated that the DAMPscore has robust prognostic capabilities. In the Meta-cohort, the area under the ROC curve (AUC) values for the DAMPscore to predict overall survival at 1, 3 and 5 years were 0.65, 0.70 and 0.77, respectively, while the AUC values for the TCGA-PAAD cohort were 0.71, 0.73 and 0.72, respectively. Additional cohorts, such as E-MTAB-6134 and ICGC-AU, corroborated the predictive power of the DAMPscore. A comparison of the DAMPscore with other prognostic models revealed that it consistently exhibited a superior C-index across most PAAD cohorts. Furthermore, in vitro experiments demonstrated that PLEK2, a hub gene related to the DAMPscore, is involved in critical biological processes such as cell proliferation, migration and invasion. In conclusion, the DAMPscore is a promising prognostic biomarker for PAAD, surpassing traditional models in various datasets. This study emphasizes the role of DAMP-related pathways in influencing tumor biology and highlights the importance of immune modulation in PAAD prognosis, suggesting that therapeutic strategies targeting DAMP signaling could improve patient outcomes.

An unconventional autophagic pathway that inhibits ATP secretion during apoptotic cell death

Mobilisation of Damage-Associated Molecular Patterns (DAMPs) determines the immunogenic properties of apoptosis, but the mechanisms that control DAMP exposure are still unclear. Here we describe an unconventional autophagic pathway that inhibits the release of ATP, a critical DAMP in immunogenic apoptosis, from dying cells. Mitochondrial BAK activated by BH3-only molecules interacts with prohibitins and stomatin-1 through its latch domain, indicating the existence of an interactome specifically assembled by unfolded BAK. This complex engages the WD40 domain of the autophagic effector ATG16L1 to induce unconventional autophagy, and the resulting LC3-positive vesicles contain ATP. Functional interference with the pathway increases ATP release during cell death, reduces ATP levels remaining in the apoptotic bodies, and improves phagocyte activation. These results reveal that an unconventional component of the autophagic burst that often accompanies apoptosis sequesters intracellular ATP to prevent its release, thus favouring the immunosilent nature of apoptotic cell death.

Metal-based immunogenic cell death inducers for cancer immunotherapy

Immunogenic cell death (ICD) has attracted enormous attention over the past decade due to its unique characteristics in cancer cell death and its role in activating innate and adaptive immune responses against tumours. Many efforts have been dedicated to screening, identifying and discovering ICD inducers, resulting in the validation of several based on metal complexes. In this review, we provide a comprehensive summary of current metal-based ICD inducers, their molecular mechanisms for triggering ICD initiation and subsequent protective antitumour immune responses, along with considerations for validating ICD both in vitro and in vivo. We also aim to offer insights into the future development of metal complexes with enhanced ICD-inducing properties and their applications in potentiating antitumour immunity.

Enhancing antitumor immunity through chemotherapeutic-derived lipid nanoparticle-induced immunogenic cell death and CD40L/Flt3L mRNA-mediated dendritic cell activation

Dendritic cells (DCs) are essential for inducing effective antitumor T cell responses. However, the immunosuppressive tumor microenvironment (TME) hinders DC recruitment and maturation, facilitating tumor progression and spread. This study investigates the synergistic potential of immunogenic cell death (ICD), triggered by chemotherapeutic-derived lipid nanoparticles (LNPs), in combination with Flt3L and CD40L mRNA delivery to enhance DC mobilization and activation, reprogram the TME, and ultimately promote robust antitumor T cell responses. The optimized LNP formulation, GEM5Q7, efficiently delivered mRNA and induced ICD in melanoma cells. Intratumoral administration of GEM5Q7, encapsulating Flt3L and CD40L mRNAs, elevated pro-inflammatory cytokine and chemokine secretion, driving the infiltration and activation of cross-presenting DCs, which are critical for priming T cells. In a subcutaneous melanoma model, this approach led to significant tumor suppression and a 40 % complete response rate. This strategy holds promise for enhancing cancer immunotherapies by reprogramming the TME and inducing durable antitumor T cell immunity.

High Expression of Calreticulin Affected the Tumor Microenvironment and Correlated With Worse Prognosis in Patients With Triple-Negative Breast Cancer

Calreticulin (CALR) preserves reticular homeostasis by maintaining correct protein folding within the endoplasmic reticulum. Immunogenic cell death (ICD) is a regulated form of cell death and could activate adaptive immune response. As one of the damage-associated molecular patterns during ICD process, surface-exposed CALR resulted in the activation of adaptive immune response. Here, we evaluated the expression patterns of CALR in a cohort of 231 untreated triple-negative breast cancer (TNBC) and determined correlations between CALR expression and clinicopathologic parameters, programmed cell death ligand 1 (PD-L1) expression in immune cells (ICs), and survival. In addition, we analyzed a TNBC data set from The Cancer Genome Atlas to explore the relationship between mRNA expression of CALR and clinicopathologic features, IC infiltration, and survival. Tissue microarray results showed that high CLAR was strongly correlated with advanced stage (P = 0.022), shorter disease-free survival (P = 0.008) and overall survival (P = 0.002), and independently predicted prognosis in TNBC. Spearman analyses demonstrated that CALR negatively correlated with PD-L1 in ICs (r = -0.198, P = 0.003). Patients with low CALR and high PD-L1 in ICs had the best disease-free survival (P = 0.013) and overall survival (P = 0.004) compared with other patients, especially the patients with high CALR and low PD-L1 in ICs. In the "The Cancer Genome Atlas" cohort, CALR mRNA expression in tumors was significantly higher than that in normal tissues (P < 0.001). CALR expression was strongly and positively related to other ICD-related genes. These findings demonstrated that the expression of CALR could independently predict the prognosis in patients with TNBC, and it may play a potential synergistic role in treatments involving immunotherapy.

Thermoresistant flagellin-adjuvanted cancer vaccine combined with photothermal therapy synergizes with anti-PD-1 treatment

BACKGROUND

Cancer immunotherapy, leveraging the immune system to target and eradicate cancer cells, has transformed cancer treatment paradigms. Immune checkpoint inhibitors (ICIs) are used in a wide array of cancers, but only a limited fraction of patients are responding. Cancer vaccines could elicit antigen-specific immune responses and establish long-term immune memory, preventing recurrence and metastasis. Despite their promising profiles, ICIs and cancer vaccines by themselves are often insufficient to overcome the immunosuppressive tumor microenvironment (TME) and recurrence/metastasis. Addressing these challenges is crucial for improving cancer immunotherapy outcomes.

METHODS

The targeted liposomal formulation (TLIF), displaying Cyclic RGD (cRGD) peptide on the surface and encapsulating ICG and thermoresistant flagellin (FlaB) inside, was used for photothermal therapy (PTT), which was designed to induce robust immunogenic cell death (ICD) and release tumor antigens (TAs). We employed a mouse breast cancer model amenable to PTT. Utilizing a bilateral DD-Her2/neu tumor implantation model, we evaluated local and abscopal effects of combinatorial approaches employing PTT, FlaB-adjuvanted peptide vaccine (FlaB-Vax), and anti-PD-1 treatment. FlaB-Vax was designed to trigger tumor-associated antigen (TAA)-specific immune responses, which will trigger specific anti-tumor immunity. TLIF-PTT aimed to reduce tumor burden and induce ICD-mediated TA liberation for epitope spreading. Sustained anti-tumor immune memory was assessed by orthotopic rechallenging cured mice with the DD-Her2/neu tumor cells.

RESULTS

The combination of TLIF-PTT and FlaB-Vax provided significantly enhanced primary tumor suppression, with strong abscopal effects and long-lasting immune memory. The addition of anti-PD-1 therapy further improved long-term relapse-free survival, highlighting the potential of this combinatorial approach to induce durable antitumor immunity and sustainably prevent cancer recurrence and metastasis.

CONCLUSION

This study demonstrates that the combination of TLIF-PTT and FlaB-Vax synergistically induced synergistic anti-tumor immune responses, which were efficaciously potentiated by anti-PD-1 treatment for recurrence-free long-term survival.

Silicasomes in Oncology: From Conventional Chemotherapy to Combined Immunotherapy

The use of nanoparticles as drug carriers in oncology has evolved from their traditional role as chemotherapy carriers to their application in immunotherapy, exploiting not only their passive accumulation in solid tumors but also their ability to interact with immune cells. Silicasomes are highly versatile nanoplatforms composed of a mesoporous silica core whose external surface is coated with a lipid bilayer that allows the co-delivery of therapeutic agents having different chemical natures (small molecules, proteins, enzymes, or oligonucleotides, among others). Herein, cutting-edge advances carried out in the development and application of silicasomes are presented, providing a general description of the performance of these nanotransporters. Additionally, the specific load of chemotherapeutic drugs is explored, followed by a discussion of the immunotherapeutic application of silicasomes and the combination of different therapeutic strategies, including theragnosis, in a single silicasome platform, highlighting the enormous potential of these nanosystems.

From cold to hot: mechanisms of hyperthermia in modulating tumor immunology for enhanced immunotherapy

The emergence of immunotherapies has revolutionized cancer treatment by leveraging the immune system to target malignancies, offering new hope where traditional therapies often fall short. Within this context, hyperthermia (HT) has re-emerged as a promising adjunctive treatment, capable of enhancing the effectiveness of radiotherapy, chemotherapy, and immunotherapy. HT influences both the innate and adaptive immune systems, enhancing the activity of immune cells such as neutrophils, NK cells, and dendritic cells, while also modulating the tumor microenvironment (TME) to promote immunogenic cell death (ICD) and reduce immunosuppressive conditions. These effects contribute to the transformation of immunologically "cold" tumors into "hot" tumors, making them more susceptible to immune-mediated destruction. Furthermore, HT can amplify the efficacy of immune checkpoint inhibitors (ICIs) by improving immune cell infiltration, inducing damage-associated molecular pattern (DAMP) release, and enhancing antigen presentation. Preclinical and clinical studies support the combination of HT with ICIs, demonstrating improved outcomes in otherwise resistant tumors. However, the full therapeutic potential of the different technologies allowing to apply HT remains to be fully understood, and further research is needed to optimize treatment protocols, explore the differential impacts of local versus whole-body hyperthermia, and identify biomarkers for patient stratification. This review underscores the multifaceted role of HT in immunity and its potential to significantly enhance the efficacy of immunotherapy.

Properties of Monocyte-Derived Dendritic Cells Loaded With Lysates of Cancer Cells Exposed to Cytotoxic Peptides

BACKGROUND

This study is based on the idea of using tumor cell membrane lysis induced by diarylethene-containing analog of cytotoxic peptides (CPs) - gramicidin S to create a new approach for obtaining dendritic cells (DCs)-based anticancer vaccine. It is supposed that cancer cells undergoing immunogenic cell death release the damage-associated molecular patterns (DAMPs), and thus enhance immunogenic maturation and activation of DCs. The aim of this study is to analyze the phenotypic and functional characteristics of the generated monocyte-derived DCs loaded with CPs-treated lysates of tumor cells.

MATERIALS AND METHODS

The triple-negative human breast cancer cell line MDA-MB-231 was used in the study. DCs were generated from peripheral blood monocytes using a recombinant human granulocytemacrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). Tumor cells were treated with LMB033 CPs containing a diarylethene fragment (photoswitch) in two ring forms - "closed" with low activity and toxicity and "open" with high activity. The obtained lysates of tumor cells were co-incubated with human monocyte-derived DCs. The analysis of the phenotypic characteristics of DCs was performed by a flow cytometry using monoclonal antibodies to CD83, CD86, CD11c, HLA-DR, and HLA-ABC. The expression level of mRNA of cytokine genes and indoleamine 2,3-dioxygenase (IDO) gene was determined using the quantitative real-time PCR.

RESULTS

The highest cytotoxic effect on MDA-MB-231 cells was detected after 6-h incubation with the open form of LMB033 at concentrations of 16 and 32 μM. The studied CPs even at the lower of the tested concentrations caused externalization of phosphatidylserine in almost 100% of apoptotic cells of MB-MDA-231 cells following 6-h incubation. Loading monocyte-derived DCs with lysate of MDA-MB-231 cells treated with LMB033 peptide in open or closed forms caused a different effect on the antigen-presenting properties of cells depending on the form of the peptide. Compared to DCs loaded with untreated lysate, a significant increase in the number of mature activated CD83+ DCs was found after loading with lysates of cells treated with open (16 μM) or closed (32 μM) forms of LMB033. CPs-induced lysates of MDA-MB-231 cells did not cause significant changes in the expression of mRNA of Th1 polarizing cytokines TNF-α, IL-12, neither did these lysates activate the transcription of the genes of immunosuppressive cytokines and IL-10, TGF-β, and the IDO gene. This indicates the absence of the activation of the immunosuppressive properties of the generated DCs.

CONCLUSION

The presented data open the prospects for developing an effective antitumor immunotherapeutic vaccine based on DCs using CPs LMB033.

Electrochemotherapy with bleomycin, oxaliplatin, or cisplatin in mouse tumor models, from tumor ablation to in situ vaccination

Introduction

In addition to its direct cytotoxic effects, ablative therapies as electrochemotherapy (ECT) can elicit indirect antitumor effects by triggering immune system responses. Here, we comprehensively analyzed this dual effectiveness of intratumoral ECT with chemotherapeutic drugs bleomycin (BLM), oxaliplatin (OXA), and cisplatin (CDDP). Our aim was to determine if ECT can act as in situ vaccination and thereby induce an abscopal effect. By evaluating ECT's potential for in situ vaccination, our goal was to pave the way for future advancements for its combination with emerging (immuno)therapies, leading to enhanced responses and outcomes.

Methods

We employed two mouse tumor models, the immunologically cold B16F10 melanoma and 4T1 mammary carcinoma, to explore both local and systemic (i.e., abscopal) antitumor effects following equieffective intratumoral ECT with BLM, OXA, and CDDP. Through histological analyses and the use of immunodeficient and metastatic (for abscopal effect) mouse models, we identified and compared both the cytotoxic and immunological components of ECT's antitumor efficiency, such as immunologically recognizable cell deaths (immunogenic cell death and necrosis) and immune infiltrate (CD11+, CD4+, CD8+, GrB+).

Results

Differences in immunological involvement after equieffective intratumoral ECT were highlighted by variable kinetics of immunologically recognizable cell deaths and immune infiltrate across the studied tumor models. Particularly, the 4T1 tumor model exhibited a more pronounced involvement of the immune component compared to the B16F10 tumor model. Variances in the antitumor (immune) response were also detected based on the chemotherapeutic drug used in ECT. Collectively, ECT demonstrated effectiveness in inducing in situ vaccination in both tumor models; however, an abscopal effect was observed in the 4T1 tumor model only.

Conclusions

This is the first preclinical study systematically comparing the immune involvement in intratumoral ECT's efficiency using three distinct chemotherapeutic drugs in mouse tumor models. The demonstrated variability in immune response to ECT across different tumor models and chemotherapeutic drugs provides a basis for future investigations aimed at enhancing the effectiveness of combined treatments.

A new paradigm for cancer immunotherapy: targeting immunogenic cell death-related noncoding RNA

Cancer immunotherapy has shown significant potential in treating several malignancies by stimulating the host immune system to recognize and attack cancer cells. Immunogenic cell death (ICD) can amplify the antitumor immune responses and reverse the immunosuppressive tumor microenvironment, thus increasing the sensitivity of cancer immunotherapy. In recent years, noncoding RNAs (ncRNAs) have emerged as key regulatory factors in ICD and oncologic immunity. Accordingly, ICD-related ncRNAs hold promise as novel therapeutic targets for optimizing the efficacy of cancer immunotherapy. However, the immunomodulatory properties of ICD-related ncRNAs have not yet been comprehensively summarized. Hence, we summarize the current knowledge on ncRNAs involved in ICD and their potential roles in cancer immunotherapy in this review. It deepens our understanding of ncRNAs associated with ICD and provides a new strategy to enhance cancer immunotherapy by specifically targeting the ICD-related ncRNAs.

Phase Ib Study for the Combination of Doxorubicin, Dacarbazine, and Nivolumab as the Upfront Treatment in Patients With Advanced Leiomyosarcoma: A Study by the Spanish Sarcoma Group (GEIS)

PURPOSE

Doxorubicin, alongside a select group of cytotoxic agents, is capable of inducing an adaptive immune response via a well-established peculiar type of tumor cell death called immunogenic cell death (ICD). We hypothesize that combining doxorubicin and dacarbazine with nivolumab may enhance therapeutic efficacy by exerting synergy in the ICD circuit. We hereby present a phase Ib trial with this combination.

PATIENTS AND METHODS

Patients with advanced leiomyosarcoma and anthracycline-naïve were eligible. The initial dose level consisted of doxorubicin 75 mg/m2 once on day 1, once every three weeks, followed by dacarbazine 400 mg/m2 once on days 1 and 2, once every three weeks, plus nivolumab 360 mg once on day 2, once every 3 weeks, for six courses and then 1 year of nivolumab. A (-1) dose level was the same regimen but with nivolumab 240 mg. A classic 3 + 3 phase-I design was used to determine the recommended phase-II dose (RP2D). Secondary end points included overall response rate, safety profile, survival, and translational research.

RESULTS

From January 2002 to July 2023, 24 patients were enrolled and 23 were evaluable for efficacy, excluding one patient because of noncompliant dose. All patients were treated with the initial dose level, then the RP2D. Toxicity was mild, with the most frequent being grade 4 toxicity neutropenia (16.7%) and thrombocytopenia (8.3%), while no grade 5 toxicity occurred. The centrally reviewed objective response rate was as follows: partial response 56.5%, stable disease 39.1%, and progression 4.4%. The 6-month progression-free survival (PFS) rate was 80% (95% CI, 63 to 98). Dynamic increases of HMGB1 in blood significantly correlated with longer PFS.

CONCLUSION

This scheme of doxorubicin, dacarbazine, and nivolumab is feasible and well tolerated. Clinical activity is encouraging and the prognostic impact of HMGB1 supports the relevance of ICD activation. Further clinical research is already underway with this concept in leiomyosarcoma.

Intra-tumoral delivery of 5'ppp-dsRNA induces a robust antitumor response via RIG-I activation and Bcl-2 gene downregulation in a murine model of prostate cancer

Onco-immunotherapy via blocking checkpoint inhibitors has revolutionized the treatment-landscape of several malignancies, though not in the metastatic castration-resistant prostate cancer (PCa) owing to an immunosuppressive and poorly immunogenic "cold" tumor microenvironment (TME). Turning up the heat of such a cold TME via triggering innate immunity is now of increasing interest to restore immune-surveillance. Retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) are cytosolic innate-sensors that can detect exogenous RNAs and induce type-I interferons and other pro-inflammatory signaling. RIG-I activation is suggested to be a valuable addition to the treatment approaches for several cancers. However, the knowledge about RIG-I signaling in PCa remains elusive. The present study evaluated the expression of two important RLRs, RIG-I and melanoma differentiation-associated protein 5 (MDA5), along with their downstream partners, mitochondrial antiviral-signaling protein (MAVS) and ERA G-protein-like 1 (ERAL1), during PCa progression in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. The early stage of PCa revealed a significant increment in the expression of RLRs but not MAVS. However, the advanced stage showed downregulated RLR signaling. Further, the therapeutic implication of 5'ppp-dsRNA, a synthetic RIG-I agonist and Bcl2 gene silencer, has been investigated in vitro and in vivo. Intra-tumoral delivery of 5'ppp-dsRNA regressed tumor growth via triggering tumor cell apoptosis, immunomodulation, and inducing phagocytic "eat me" signals. These findings highlight that, for the first time, RIG-I activation and Bcl-2 silencing with 5'ppp-dsRNA can serve as a potent tumor-suppressor strategy in PCa and has a significant clinical implication in transforming a "cold" TME into an immunogenic "hot" TME of PCa.

AI-based classification of anticancer drugs reveals nucleolar condensation as a predictor of immunogenicity

BACKGROUND

Immunogenic cell death (ICD) inducers are often identified in phenotypic screening campaigns by the release or surface exposure of various danger-associated molecular patterns (DAMPs) from malignant cells. This study aimed to streamline the identification of ICD inducers by leveraging cellular morphological correlates of ICD, specifically the condensation of nucleoli (CON).

METHODS

We applied artificial intelligence (AI)-based imaging analyses to Cell Paint-stained cells exposed to drug libraries, identifying CON as a marker for ICD. CON was characterized using SYTO 14 fluorescent staining and holotomographic microscopy, and visualized by AI-deconvoluted transmitted light microscopy. A neural network-based quantitative structure-activity relationship (QSAR) model was trained to link molecular descriptors of compounds to the CON phenotype, and the classifier was validated using an independent dataset from the NCI-curated mechanistic collection of anticancer agents.

RESULTS

CON strongly correlated with the inhibition of DNA-to-RNA transcription. Cytotoxic drugs that inhibit RNA synthesis without causing DNA damage were as effective as conventional cytotoxicants in inducing ICD, as demonstrated by DAMPs release/exposure and vaccination efficacy in mice. The QSAR classifier successfully predicted drugs with a high likelihood of inducing CON.

CONCLUSIONS

We developed AI-based algorithms for predicting CON-inducing drugs based on molecular descriptors and their validation using automated micrographs analysis, offering a new approach for screening ICD inducers with minimized adverse effects in cancer therapy.

Epigallocatechin-3-gallate induces immunogenic cell death and enhances cancer immunotherapy in colorectal cancer

The induction of immunogenic cell death (ICD) can activate antitumor immune response to potentiate cancer immunotherapy. In this study, we observed the antitumor activity following combinatorial therapy with anti-CTLA4 antibody and epigallocatechin-3-gallate (EGCG) in CT26 tumors.Indeed, EGCG triggered colon cancer cells ICD with the secretion of high-mobility group protein B1 (HMGB1) and the surface expression of calreticulin (CRT) and heat shock protein 70 (HSP70). Mice treated with EGCG promoted the maturation of dendritic cells and enhanced the effector function of CD8+ T cells within tumors to remodel the tumor immune microenvironment. Overall, these results indicate that EGCG, a novel ICD inducer, triggers ICD in CRC, and provides a new concept for cancer immunotherapy.

Cannabinoid-Induced Immunogenic Cell Death of Colorectal Cancer Cells Through De Novo Synthesis of Ceramide Is Partially Mediated by CB2 Receptor

Background: Our recent studies have identified a link between sphingolipid metabolites and the induction of a specialized form of regulated cell death termed immunogenic cell death (ICD). We have recently demonstrated that the synthetic cannabinoid (±) 5-epi CP 55,940 (5-epi) stimulates the accumulation of ceramide (Cer), and that inhibition of sphingosine kinase 1 (SphK1) enhances Cer accumulation and ICD-induction in human colorectal cancer (CRC) cell lines. Methods: We employed flow-cytometric, western blot analyses, pharmacological inhibitors of the sphingolipid metabolic pathway and small molecule agonists and antagonists of the CB receptors to further analyze the mechanism by which 5-epi induces Cer accumulation. Results: Herein, and report that 5-epi induces de novo synthesis of Cer primarily through engagement of the cannabinoid receptor 2 (CB2) and depletion of intracellular calcium levels. Moreover, we report that 5-epi stimulates Cer synthesis through dysregulation of the endogenous inhibitor of the de novo Cer pathway, ORMDL3. We also observed a remarkable and specific accumulation of one Cer species, C20:4 Cer, generated predominantly by ceramide synthase 4, as a key factor required for 5-epi-induced ICD. Conclusions: Together, these data indicate that engagement of CB2, by 5-epi, alters regulation of the de novo ceramide synthesis pathway to generate Cer species that mediate ICD.

Use of drug-killed cancer cells: A method to assess the therapeutic effectiveness of immunogenic cell death

Cancer immunotherapy has revolutionized cancer treatment by harnessing the immune system's potential to combat cancer. Among the various strategies in this field, the use of killed tumor cells (KC) induced by immunogenic cell death (ICD) inducers has gained attraction. This approach involves the treatment of cancer cells in vitro, followed by the subcutaneous injection of these killed cells into tumor-bearing mice. ICD induction triggers the exposure and release of damage-associated molecular patterns (DAMPs) and neoantigens, activating both innate and adaptive immune responses against cancer. Vaccination assays with immunocompetent mice and syngeneic cancer cells are considered the gold standard for identifying ICD inductors, as they effectively demonstrate the immunized host's capacity to achieve tumor rejection, typically showing more than 50% of protection. Despite significant progress in understanding ICD mechanisms, translating these findings into clinical practice faces challenges. Controversially, some reports indicate ICD induction with <50% protection in prophylactic vaccination. This variability in ICD interpretation can lead to "false positives" or overestimations of the immunogenicity of cell death induced by antitumor treatments, potentially complicating its clinical translation. Thus, rigorous adherence to the gold standard is necessary, and complementary experiments to assess the immunogenicity of cell death are advantageous. Here, we present a protocol to confirm the immunogenicity and therapeutic effectiveness of cell death induced by an ICD-inducer and evaluate its ability to reduce tumor burden in an established syngeneic mouse model.

Tumor-targeting bacteria as immune stimulants - the future of cancer immunotherapy?

Cancer immunotherapies have been widely hailed as a breakthrough for cancer treatment in the last decade, epitomized by the unprecedented results observed with checkpoint blockade. Even so, only a minority of patients currently achieve durable remissions. In general, responsive patients appear to have either a high number of tumor neoantigens, a preexisting immune cell infiltrate in the tumor microenvironment, or an 'immune-active' transcriptional profile, determined in part by the presence of a type I interferon gene signature. These observations suggest that the therapeutic efficacy of immunotherapy can be enhanced through strategies that release tumor neoantigens and/or produce a pro-inflammatory tumor microenvironment. In principle, exogenous tumor-targeting bacteria offer a unique solution for improving responsiveness to immunotherapy. This review discusses how tumor-selective bacterial infection can modulate the immunological microenvironment of the tumor and the potential for combination with cancer immunotherapy strategies to further increase therapeutic efficacy. In addition, we provide a perspective on the clinical translation of replicating bacterial therapies, with a focus on the challenges that must be resolved to ensure a successful outcome.

Combination of Losartan and Platinum Nanoparticles with Photothermal Therapy Induces Immunogenic Cell Death Effective Against Neuroblastoma

Introduction

Photothermal therapy (PTT) is a promising therapeutic procedure with minimal side effects, which can not only kill tumor directly but also cause immunogenic cell death (ICD). However, most solid tumors, including neuroblastoma, are abundant in fibroblasts, which limit the penetration and delivery of nanoparticles. Losartan is an antihypertensive drug approved by the FDA, and it has been proved to have the effect of breaking down excessive ECM network.

Methods

In this study, we investigated the application and potential mechanism of the combination of mesoporous platinum nanoparticles (MPNs) and losartan in the PTT of neuroblastoma by establishing neuroblastoma models in vitro and in vivo.

Results

Compared to the MPNs group without 808 nm laser irradiation, Neuro-2a cells pretreated with PTT and losartan showed lower survival rates, increased surface calreticulin, and higher release of HMGB1 and ATP. The group also exhibited the highest anti-tumor efficacy in vivo, with a tumor suppression ratio of approximately 80%. Meanwhile, we found that CD3+ T cells, CD4+ T cells and CD8+ T cells from the peripheral blood of experimental group mice were significantly higher than control groups, and CD8+PD-1+ cells were significantly lower than those in MPNs + Los group and Los + laser group. And the expression of PD-1 and α-SMA in Neuro-2a tumors tissue was reduced. Furthermore, losartan could reduce damage of liver function caused by MPNs and laser treatment.

Conclusion

This study demonstrated that losartan-induced fibroblasts ablation increased the penetration of MPNs into tumors. Enhanced penetration allowed PTT to kill more tumor cells and synergistically activate immune cells, leading to ICD, indicating the great promise of the strategy for treating neuroblastoma in vivo.

Best practices and novel approaches for the preclinical development of drug-radiotherapy combinations for cancer treatment

Drug-radiation combination therapy is a practical approach to improving clinical outcomes for many tumours. Unfortunately, most clinical combination studies combine drugs with radiotherapy empirically and do not exploit mechanistic synergy in cell death and the interconnectivity of molecular pathways of tumours or rationale for selecting the dose, fractionation, and schedule, which can result in suboptimal efficacy and exacerbation of toxic effects. However, opportunities exist to generate compelling preclinical evidence for combination therapies from fit-for-purpose translational studies for simulating the intended clinical study use scenarios with standardised preclinical assays and algorithms to evaluate complex molecular interactions and analysis of synergy before clinical research. Here, we analyse and discuss the core issues in the translation of preclinical data to enhance the relevance of preclinical assays, in vitro clonogenic survival along with apoptosis, in vivo tumour regression and growth delay assays, and toxicology of organs at risk without creating barriers to innovation and provide a synopsis of emerging areas in preclinical radiobiology.

Inhibition of ATM or ATR in combination with hypo-fractionated radiotherapy leads to a different immunophenotype on transcript and protein level in HNSCC

Background

The treatment of head and neck tumors remains a challenge due to their reduced radiosensitivity. Small molecule kinase inhibitors (smKI) that inhibit the DNA damage response, may increase the radiosensitivity of tumor cells. However, little is known about how the immunophenotype of the tumor cells is modulated thereby. Therefore, we investigated whether the combination of ATM or ATR inhibitors with hypo-fractionated radiotherapy (RT) has a different impact on the expression of immune checkpoint markers (extrinsic), the release of cytokines or the transcriptome (intrinsic) of head and neck squamous cell carcinoma (HNSCC) cells.

Methods

The toxic and immunogenic effects of the smKI AZD0156 (ATMi) and VE-822 (ATRi) in combination with a hypo-fractionated scheme of 2x5Gy RT on HPV-negative (HSC4, Cal-33) and HPV-positive (UM-SCC-47, UD-SCC-2) HNSCC cell lines were analyzed as follows: cell death (necrosis, apoptosis; detected by AnxV/PI), expression of immunostimulatory (ICOS-L, OX40-L, TNFSFR9, CD70) and immunosuppressive (PD-L1, PD-L2, HVEM) checkpoint marker using flow cytometry; the release of cytokines using multiplex ELISA and the gene expression of Cal-33 on mRNA level 48 h post-RT.

Results

Cell death was mainly induced by the combination of RT with both inhibitors, but stronger with ATRi. Further, the immune phenotype of cancer cells, not dying from combination therapy itself, is altered predominantly by RT+ATRi in an immune-stimulatory manner by the up-regulation of ICOS-L. However, the analysis of secreted cytokines after treatment of HNSCC cell lines revealed an ambivalent influence of both inhibitors, as we observed the intensified secretion of IL-6 and IL-8 after RT+ATRi. These findings were confirmed by RNAseq analysis and further the stronger immune-suppressive character of RT+ATMi was enlightened. We detected the down-regulation of a central protein of cytoplasmatic sensing pathways of nucleic acids, RIG-1, and found one immune-suppressive target, EDIL3, strongly up-regulated by RT+ATMi.

Conclusion

Independent of a restrictive toxicity, the combination of RT + either ATMi or ATRi leads to comprehensive and immune-modulating alterations in HNSCC. This includes pro-inflammatory signaling induced by RT + ATRi but also anti-inflammatory signals. These findings were confirmed by RNAseq analysis, which further highlighted the immune-suppressive nature of RT + ATMi.

Cytofluorometric analysis of the maturation and activation of bone marrow-derived dendritic cells to assess immunogenic cell death

Immunogenic cell death (ICD) has emerged as a pivotal form of cell death in anti-cancer therapy as it combines the ability to both eliminate cancer cells and simultaneously activate anti-tumor immunity, thereby contributing to the establishment of long-term immunological memory. Antigen-presenting cells (APCs), with an emphasis on dendritic cells (DCs), play a central role in bridging the innate and adaptive immune systems. DCs recognize and present antigens derived from the dying cancer cells to T cells in the lymph nodes, resulting in T cell activation. The activation and maturation of DCs thus marks the initiation of a cycle of anti-tumor immunity. In this chapter, we provide straightforward methodologies to isolate DCs from murine bone marrow (bone marrow-derived DCs, BMDCs), induce immunogenic apoptosis in murine MCA205 fibrosarcoma cells using ICD inducer mitoxantrone (MTX), co-cultivate BMDCs with the MTX-treated cancer cells, and to assess the activation and maturation status of BMDCs by flow cytometric-assisted quantification of co-stimulatory molecules (MHC II, CD86, CD80) expressed on the plasma membrane of BMDCs. With minor adjustments, the same protocol can be implemented to other cancer cell lines or to analyze the phenotypic status of non-professional APCs.

Photothermal therapy co-localized with CD137 agonism improves survival in an SM1 melanoma model without hepatotoxicity

Aim: We investigate combining Prussian Blue nanoparticles (PBNPs), as photothermal therapy (PTT) agents, with agonistic CD137 antibodies (αCD137) on a single nanoparticle platform to deliver non-toxic, anti-tumor efficacy in SM1 murine melanoma.Methods: We electrostatically coated PBNPs with αCD137 (αCD137-PBNPs) and quantified their physicochemical characteristics, photothermal and co-stimulatory capabilities. Next, we tested the efficacy and hepatotoxicity of PTT using αCD137-PBNPs (αCD137-PBNP-PTT) in SM1 tumor-bearing mice.Results: The αCD137-PBNPs retained both the photothermal and agonistic properties of the PBNPs and αCD137, respectively. In vivo, SM1 tumor-bearing mice treated with αCD137-PBNP-PTT exhibited a significantly higher survival rate (50%) without hepatotoxicity, compared with control treatments.Conclusion: These data suggest the potential utility of co-localizing PBNP-PTT with αCD137-based agonism as a novel combination nanomedicine.

Tartrolon D induces immunogenic cell death in melanoma

Tartrolon D (TRL) is produced by Teredinibacter turnerae, a symbiotic cellulose-degrading bacteria in shipworm gills. Immunogenic cell death (ICD) induction contributes to a better and longer-lasting response to anticancer treatment. Tumor cells undergoing ICD trigger activation of the immune system, as a vaccine.

AIMS

This study aimed to evaluate ICD induction by TRL.

MAIN METHODS

Cell viability was evaluated by SRB assay. Cell stress, cell death, ICD features and antigen-presenting molecules were evaluated by flow cytometry and immunoblot.

KEY FINDINGS

TRL showed antiproliferative activity on 7 tumor cell lines (L929, HCT 116, B16-F10, WM293A, SK-MEL-28, PC-3M, and MCF-7) and a non-tumor cell (HEK293A), with an inhibition concentration mean (IC50) ranging from 0.03 μM to 13 μM. Metastatic melanomas, SK-MEL-28, B16-F10, and WM293A, were more sensitive cell lines, with IC50 ranging from 0.07 to 1.2 μM. TRL induced apoptosis along with autophagy and endoplasmic reticulum stress and release of typical damage-associated molecular patterns (DAMPs) of ICD such calreticulin, ERp57, and HSP70 exposure, and HMGB1 release. Additionally, melanoma B16-F10 exposed to TRL increased expression of antigen-presenting molecules MHC II and CD1d and induced activation of splenocytes of C57BL/6 mice.

SIGNIFICANCE

In spite of recent advances provided by target therapy and immunotherapy, advanced metastatic melanoma is incurable for more than half of patients. ICD inducers yield better and long-lasting responses to anticancer treatment. Our findings shed light on an anticancer candidate of marine origin that induces ICD in melanoma.

Tutorial: design, production and testing of oncolytic viruses for cancer immunotherapy

Oncolytic viruses (OVs) represent a novel class of cancer immunotherapy agents that preferentially infect and kill cancer cells and promote protective antitumor immunity. Furthermore, OVs can be used in combination with established or upcoming immunotherapeutic agents, especially immune checkpoint inhibitors, to efficiently target a wide range of malignancies. The development of OV-based therapy involves three major steps before clinical evaluation: design, production and preclinical testing. OVs can be designed as natural or engineered strains and subsequently selected for their ability to kill a broad spectrum of cancer cells rather than normal, healthy cells. OV selection is further influenced by multiple factors, such as the availability of a specific viral platform, cancer cell permissivity, the need for genetic engineering to render the virus non-pathogenic and/or more effective and logistical considerations around the use of OVs within the laboratory or clinical setting. Selected OVs are then produced and tested for their anticancer potential by using syngeneic, xenograft or humanized preclinical models wherein immunocompromised and immunocompetent setups are used to elucidate their direct oncolytic ability as well as indirect immunotherapeutic potential in vivo. Finally, OVs demonstrating the desired anticancer potential progress toward translation in patients with cancer. This tutorial provides guidelines for the design, production and preclinical testing of OVs, emphasizing considerations specific to OV technology that determine their clinical utility as cancer immunotherapy agents.

Immunogenic cell death inducers for cancer therapy: An emerging focus on natural products

BACKGROUND

Immunogenic cell death (ICD) is a specific form of regulated cell death induced by a variety of stressors. During ICD, the dying cancer cells release damage-associated molecular patterns (DAMPs), which promote dendritic cell maturation and tumor antigen presentation, subsequently triggering a T-cell-mediated anti-tumor immune response. In recent years, a growing number of studies have demonstrated the potential of natural products to induce ICD and enhance tumor cell immunogenicity. Moreover, there is an increasing interest in identifying new ICD inducers from natural products.

PURPOSE

This study aimed to emphasize the potential of natural products and their derivatives as ICD inducers to promote research on using natural products in cancer therapy and provide ideas for future novel immunotherapies based on ICD induction.

METHOD

This review included a thorough search of the PubMed, Web of Science, Scopus, and Google Scholar databases to identify natural products with ICD-inducing capabilities. A comprehensive search for clinical trials on natural ICD inducers was also conducted using ClinicalTrials.gov, as well as the approved patents using the Espacenet and CNKI Patent Database.

RESULTS

Natural compounds that induce ICD can be categorized into several groups, such as polyphenols, flavonoids, terpenoids, and alkaloids. Natural products can induce the release of DAMPs by triggering endoplasmic reticulum stress, activation of autophagy-related pathways, and reactive oxygen species generation, etc. Ultimately, they activate anti-tumor immune response and improve the efficacy of cancer treatments.

CONCLUSION

A growing number of ICD inducers from natural products with promising anti-cancer potential have been identified. The detailed information presented in this review will contribute to the further development of natural ICD inducers and cancer treatment strategies based on ICD-induced responses.

Emerging role of immunogenic cell death in cancer immunotherapy: Advancing next-generation CAR-T cell immunotherapy by combination

Immunogenic cell death (ICD) is a stress-driven form of regulated cell death (RCD) in which dying tumor cells' specific signaling pathways are activated to release damage-associated molecular patterns (DAMPs), leading to the robust anti-tumor immune response as well as a reversal of the tumor immune microenvironment from "cold" to "hot". Chimeric antigen receptor (CAR)-T cell therapy, as a landmark in anti-tumor immunotherapy, plays a formidable role in hematologic malignancies but falls short in solid tumors. The Gordian knot of CAR-T cells for solid tumors includes but is not limited to, tumor antigen heterogeneity or absence, physical and immune barriers of tumors. The combination of ICD induction therapy and CAR-T cell immunotherapy is expected to promote the intensive use of CAR-T cell in solid tumors. In this review, we summarize the characteristics of ICD, stress-responsive mechanism, and the synergistic effect of various ICD-based therapies with CAR-T cells to effectively improve anti-tumor capacity.

Targeting ERK-MYD88 interaction leads to ERK dysregulation and immunogenic cancer cell death

The quest for targeted therapies is critical in the battle against cancer. The RAS/MAP kinase pathway is frequently implicated in neoplasia, with ERK playing a crucial role as the most distal kinase in the RAS signaling cascade. Our previous research demonstrated that the interaction between ERK and MYD88, an adaptor protein in innate immunity, is crucial for RAS-dependent transformation and cancer cell survival. In this study, we examine the biological consequences of disrupting the ERK-MYD88 interaction through the ERK D-recruitment site (DRS), while preserving ERK's kinase activity. Our results indicate that EI-52, a small-molecule benzimidazole targeting ERK-MYD88 interaction induces an HRI-mediated integrated stress response (ISR), resulting in immunogenic apoptosis specific to cancer cells. Additionally, EI-52 exhibits anti-tumor efficacy in patient-derived tumors and induces an anti-tumor T cell response in mice in vivo. These findings suggest that inhibiting the ERK-MYD88 interaction may be a promising therapeutic approach in cancer treatment.

Dihydroartemisinin restores the immunogenicity and enhances the anticancer immunosurveillance of cisplatin by activating the PERK/eIF2α pathway

BACKGROUND

Immunosurveillance is pivotal in the effectiveness of anticancer therapies and tumor control. The ineffectiveness of cisplatin in activating the immunosurveillance is attributed to its lack of adjuvanticity resulting from its inability to stimulate endoplasmic reticulum stress. Dihydroartemisinin demonstrates the anti-tumor effects through various mechanisms, including the activation of the endoplasmic reticulum stress. This study aimed to develop a novel strategy to enhance the immunogenicity of dying tumor cells by combining cisplatin with dihydroartemisinin, thereby triggering effective anti-tumor immunosurveillance and improving the efficacy of cisplatin in clinical practice.

METHODS

Lewis lung carcinoma (LLC) and CT26 colon cancer cell lines and subcutaneous tumor models were used in this study. The importance of immunosurveillance was validated in both immunocompetent and immunodeficient mouse models. The ability of dihydroartemisinin and cisplatin therapy to induce immunogenic cell death and tumor growth control in vivo was validated by prophylactic tumor vaccination and therapeutic tumor models. The underlying mechanism was elucidated through the pharmaceutical or genetic intervention of the PERK/eIF2α pathway in vitro and in vivo.

RESULTS

Dihydroartemisinin enhanced the generation of reactive oxygen species in cisplatin-treated LLC and CT26 cancer cells. The combination treatment of dihydroartemisinin with cisplatin promoted cell death and ensured an optimal release of damage-associated molecular patterns from dying cancer cells, promoting the phagocytosis of dendritic cells. In the tumor vaccination model, we confirmed that dihydroartemisinin plus cisplatin treatment induced immunogenic cell death. Utilizing immunocompetent and immunodeficient mouse models, we further demonstrated that the combination treatment suppressed the tumor growth of CT26 colon cancer and LLC lung cancer, leading to an improved prognosis through the restoration of cytotoxic T lymphocyte responses and reinstatement of anti-cancer immunosurveillance in vivo. Mechanistically, dihydroartemisinin restored the immunogenicity of cisplatin by activating the adjuvanticity of damage-associated molecular patterns, such as calreticulin exposure, through the PERK/eIF2α pathway. Additionally, the inhibition of eIF2α phosphorylation attenuated the anti-tumor efficiency of C + D in vivo.

CONCLUSIONS

We highlighted that dihydroartemisinin acts as an immunogenic cell death rescuer for cisplatin, activating anticancer immunosurveillance in a PERK/eIF2α-dependent manner and offering a strategy to enhance the anti-tumor efficacy of cisplatin in clinical practice.

Spatial distribution of tumour immune infiltrate predicts outcomes of patients with high-risk soft tissue sarcomas after neoadjuvant chemotherapy

BACKGROUND

Anthracycline-based neoadjuvant chemotherapy (NAC) may modify tumour immune infiltrate. This study characterized immune infiltrate spatial distribution after NAC in primary high-risk soft tissue sarcomas (STS) and investigate association with prognosis.

METHODS

The ISG-STS 1001 trial randomized STS patients to anthracycline plus ifosfamide (AI) or a histology-tailored (HT) NAC. Four areas of tumour specimens were sampled: the area showing the highest lymphocyte infiltrate (HI) at H&E; the area with lack of post-treatment changes (highest grade, HG); the area with post-treatment changes (lowest grade, LG); and the tumour edge (TE). CD3, CD8, PD-1, CD20, FOXP3, and CD163 were analyzed at immunohistochemistry and digital pathology. A machine learning method was used to generate sarcoma immune index scores (SIS) that predict patient disease-free and overall survival (DFS and OS).

FINDINGS

Tumour infiltrating lymphocytes and PD-1+ cells together with CD163+ cells were more represented in STS histologies with complex compared to simple karyotype, while CD20+ B-cells were detected in both these histology groups. PD-1+ cells exerted a negative prognostic value irrespectively of their spatial distribution. Enrichment in CD20+ B-cells at HI and TE areas was associated with better patient outcomes. We generated a prognostic SIS for each tumour area, having the HI-SIS the best performance. Such prognostic value was driven by treatment with AI.

INTERPRETATION

The different spatial distribution of immune populations and their different association with prognosis support NAC as a modifier of tumour immune infiltrate in STS.

FUNDING

Pharmamar; Italian Ministry of Health [RF-2019-12370923; GR-2016-02362609]; 5 × 1000 Funds-2016, Italian Ministry of Health; AIRC Grant [ID#28546].

Combination treatment with PD1/PDL-1 inhibitors for sarcomas: state of the art, next questions

PURPOSE OF REVIEW

Only a small fraction of sarcomas exhibit recognized parameters of immune sensitivity, such as tumor mutational burden, PDL-1 expression, or microsatellite instability. Combined strategies aimed to modulate tumor microenvironment to increase the efficacy of PD1/PDL-1 inhibitors in sarcoma. Most explored prospective studies were based on combinations of PD1/PDL-1 inhibitors with antiangiogenics, other immune checkpoints, or chemotherapy.

RECENT FINDINGS

Results on 6-month PFS rate, median PFS, and ORR in trials using PD1/PDL-1 inhibitors plus antiangiogenics ranged respectively as 46.9-55%, 4.7-7.8 months and 21-36.7%. In combination with other immune checkpoint inhibitors, the results of median PFS and ORR ranged from 2.8-4.1 months and 10-16%, respectively. In combination with chemotherapy, the best results were obtained with doxorubicin-based regimens compared to other agents. Duplet-based chemotherapy plus anti-PD1/PDL-1 obtained the highest ORR (56.2%) compared with doxorubicin (19-36.7%). Currently, the most robust predictive biomarker for anti-PD1/PDL-1 efficacy is the presence of tertiary lymphoid structures (TLS) with mature dendritic cells.

SUMMARY

Even when direct comparisons between PD1/PDL-1 inhibitor-based combinations and single agents have not been performed yet in sarcoma, some combinations appear promising. Studies controlling heterogeneity by biomarker or histotype selection contribute to an increase in efficacy or knowledge crucial for future comparative trials.

Signature identification based on immunogenic cell death-related lncRNAs to predict the prognosis and immune activity of patients with endometrial carcinoma

Background

Endometrial carcinoma (EC) is one of the most prevalent gynecologic malignancies and requires further classification for treatment and prognosis. Long non-coding RNAs (lncRNAs) and immunogenic cell death (ICD) play a critical role in tumor progression. Nevertheless, the role of lncRNAs in ICD in EC remains unclear. This study aimed to explore the role of ICD related-lncRNAs in EC via bioinformatics and establish a prognostic risk model based on the ICD-related lncRNAs. We also explored immune infiltration and immune cell function across prognostic groups and made treatment recommendations.

Methods

A total of 552 EC samples and clinical data of 548 EC patients were extracted from The Cancer Genome Atlas (TCGA) database and University of California Santa Cruz (UCSC) Xena, respectively. A prognostic-related feature and risk model was developed using the least absolute shrinkage and selection operator (LASSO). Subtypes were classified with consensus cluster analysis and validated with t-Distributed Stochastic Neighbor Embedding (tSNE). Kaplan-Meier analysis was conducted to assess differences in survival. Infiltration by immune cells was estimated by single sample gene set enrichment analysis (ssGSEA), Tumor IMmune Estimation Resource (TIMER) algorithm. Quantitative polymerase chain reaction (qPCR) was used to detect lncRNAs expression in clinical samples and cell lines. A series of studies was conducted in vitro and in vivo to examine the effects of knockdown or overexpression of lncRNAs on ICD.

Results

In total, 16 ICD-related lncRNAs with prognostic values were identified. Using SCARNA9, FAM198B-AS1, FKBP14-AS1, FBXO30-DT, LINC01943, and AL161431.1 as risk model, their predictive accuracy and discrimination were assessed. We divided EC patients into high-risk and low-risk groups. The analysis showed that the risk model was an independent prognostic factor. The prognosis of the high- and low-risk groups was different, and the overall survival (OS) of the high-risk group was lower. The low-risk group had higher immune cell infiltration and immune scores. Consensus clustering analysis divided the samples into four subtypes, of which cluster 4 had higher immune cell infiltration and immune scores.

Conclusions

A prognostic signature composed of six ICD related-lncRNAs in EC was established, and a risk model based on this signature can be used to predict the prognosis of patients with EC.

Celecoxib Augments Paclitaxel-Induced Immunogenic Cell Death in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly aggressive malignancy that lacks effective targeted therapies. Inducing immunogenic cell death (ICD) in tumor cells represents a promising strategy to enhance therapeutic efficacy by promoting antitumor immunity. Paclitaxel (PTX), a commonly used chemotherapy drug for TNBC, can induce ICD; however, the resulting immunogenicity is limited. Thus, there is an urgent need to explore strategies that improve the effectiveness of ICD in TNBC by incorporating immunoregulatory agents. This study investigated the potential of celecoxib (CXB) to enhance PTX-induced ICD by blocking the biosynthesis of PGE2 in the tumor cells. We observed that the combination of CXB and PTX promoted the maturation of dendritic cells and primed a T cell-dependent immune response, leading to enhanced tumor rejection in a vaccination assay. To further optimize drug delivery in vivo, we developed cRGD-modified liposomes for the targeted codelivery of CXB and PTX. This delivery system significantly improved drug accumulation and triggered robust antitumor immunity in an orthotopic mouse model of TNBC. Moreover, it served as an in situ vaccine to inhibit tumor recurrence and lung metastasis. Overall, our findings provide in-depth insights into the therapeutic mechanism underlying the combination of CXB and PTX, highlighting their potential as effective immune-based therapies for TNBC.

Integration of Single-Cell RNA Sequencing and Bulk RNA Sequencing to Identify an Immunogenic Cell Death-Related 5-Gene Prognostic Signature in Hepatocellular Carcinoma

Introduction

Immunogenic cell death (ICD) can enhance the potency of immunotherapy in cancer treatment. Nevertheless, it is ambiguous how ICD-related genes (ICDRGs) contribute to hepatocellular carcinoma (HCC).

Methods

Single-cell RNA sequencing (scRNA-seq) data were used to distinguish malignant cells from normal cells in the HCC tumor microenvironment(TME). Bulk RNA sequencing data was employed to acquire the landscape of the 33 ICDRGs. Unsupervised clustering identified two ICD molecular subtypes. The cellular infiltration characteristics and biological behavior in different subtypes were analyzed by ssGSEA. Subsequently, differentially expressed genes (DEGs) between the two subtypes were determined, based on which patients were classified into three gene clusters. Then, the prognostic model was constructed by Lasso-Cox analysis. Finally, we investigated the expression of risk genes in cancer cell line encyclopedia (CCLE) and validated the function of NKX3-2 in vitro experiments.

Results

ICD scores and ICDRGs expression in malignant cells were significantly lower than in normal cells by scRNA-seq analysis. ICD-high subtype was characterized by ICD-related gene overexpression and high levels of immune infiltration abundance and immune checkpoints; Three DEGs-related gene clusters were likewise strongly linked to stromal and immunological activation. In the ICD-related prognostic model consisting of NKX3-2, CHODL, MMP1, NR0B1, and CTSV, the low-risk group patients had a better endpoint and displayed increased susceptibility to immunotherapy and chemotherapeutic drugs like 5-Fluorouracil, afatinib, bortezomib, cediratinib, lapatinib, dasatinib, gefitinib and crizotinib. Moreover, NKX3-2 amplification in HCC samples has been verified by experiments, and its disruption suppressed the proliferation and invasion of tumor cells.

Conclusion

Our study highlighted the potential of the ICDRGs risk score as a prognostic indicator to aid in the accurate diagnosis and immunotherapy sensitivity of HCC.

Emerging role of immunogenic cell death in cancer immunotherapy

Cancer immunotherapy, such as immune checkpoint blockade (ICB), has emerged as a groundbreaking approach for effective cancer treatment. Despite its considerable potential, clinical studies have indicated that the current response rate to cancer immunotherapy is suboptimal, primarily attributed to low immunogenicity in certain types of malignant tumors. Immunogenic cell death (ICD) represents a form of regulated cell death (RCD) capable of enhancing tumor immunogenicity and activating tumor-specific innate and adaptive immune responses in immunocompetent hosts. Therefore, gaining a deeper understanding of ICD and its evolution is crucial for developing more effective cancer therapeutic strategies. This review focuses exclusively on both historical and recent discoveries related to ICD modes and their mechanistic insights, particularly within the context of cancer immunotherapy. Our recent findings are also highlighted, revealing a mode of ICD induction facilitated by atypical interferon (IFN)-stimulated genes (ISGs), including polo-like kinase 2 (PLK2), during hyperactive type I IFN signaling. The review concludes by discussing the therapeutic potential of ICD, with special attention to its relevance in both preclinical and clinical settings within the field of cancer immunotherapy.

Immunotherapy combined with cranial radiotherapy for driver-negative non-small-cell lung cancer brain metastases: a retrospective study

Background: This study assesses immune checkpoint inhibitors' efficacy for non-small-cell lung cancer (NSCLC) with brain metastases (BM) and explores the role of cranial radiation therapy (CRT) in the immunotherapy era. Methods: The retrospective analysis screened NSCLC patients with BMs from July 2018 to December 2021. Treatment involved chemotherapy combined with immune checkpoint inhibitors as the first-line, with patients divided into CRT and non-CRT groups. Overall survival (OS), progression-free survival and intracranial progression-free survival were calculated and compared. Results: Among 113 patients, 74 who received CRT had significantly better median OS (not reached vs 15.31 months), particularly among those with one to three BMs. Factors correlating with better OS included CRT, PD-L1 expression and diagnosis-specific graded prognostic assessment scores. Conclusion: Integrating CRT with anti-PD-1 therapy notably enhanced long-term survival in NSCLC patients with BMs.

Enhancing cancer immunotherapy with photodynamic therapy and nanoparticle: making tumor microenvironment hotter to make immunotherapeutic work better

Cancer immunotherapy has made tremendous advancements in treating various malignancies. The biggest hurdle to successful immunotherapy would be the immunosuppressive tumor microenvironment (TME) and low immunogenicity of cancer cells. To make immunotherapy successful, the 'cold' TME must be converted to 'hot' immunostimulatory status to activate residual host immune responses. To this end, the immunosuppressive equilibrium in TME should be broken, and immunogenic cancer cell death ought to be induced to stimulate tumor-killing immune cells appropriately. Photodynamic therapy (PDT) is an efficient way of inducing immunogenic cell death (ICD) of cancer cells and disrupting immune-restrictive tumor tissues. PDT would trigger a chain reaction that would make the TME 'hot' and have ICD-induced tumor antigens presented to immune cells. In principle, the strategic combination of PDT and immunotherapy would synergize to enhance therapeutic outcomes in many intractable tumors. Novel technologies employing nanocarriers were developed to deliver photosensitizers and immunotherapeutic to TME efficiently. New-generation nanomedicines have been developed for PDT immunotherapy in recent years, which will accelerate clinical applications.

Sphingosine-1-Phosphate Inhibition Increases Endoplasmic Reticulum Stress to Enhance Oxaliplatin Sensitivity in Pancreatic Cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer resistant to current therapies, including oxaliplatin (Oxa). Growing evidence supports the ability of cancers to harness sphingolipid metabolism for survival. Sphingosine-1-phosphate (S1P) is an anti-apoptotic, pro-survival mediator that can influence cellular functions such as endoplasmic reticulum (ER) stress. We hypothesize that PDAC drives dysregulated sphingolipid metabolism and that S1P inhibition can enhance ER stress to improve therapeutic response to Oxa in PDAC.

Methods

RNA sequencing data of sphingolipid mediators from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression Project (GTEx) datasets were analyzed. Murine and human PDAC cell lines were treated with small interfering RNA (siRNA) against sphingosine kinase-2 (SPHK2) or ABC294640 (ABC) and incubated with combinations of vehicle control or Oxa. In an orthotopic syngeneic KPC PDAC model, tumors were treated with either vehicle control, Oxa, ABC, or combination therapy.

Results

RNA sequencing analysis revealed multiple significantly differentially expressed sphingolipid mediators (P < 0.05). In vitro, both siRNA knockdown of SPHK2 and ABC sensitized cells to Oxa therapy (P < 0.05), and induced eukaryotic initiation factor 2α (eIF2α) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) phosphorylation, hallmarks of ER stress. In vitro therapy also increased extracellular high mobility group box 1 (HMGB1) release (P < 0.05), necessary for immunogenic cell death (ICD). In vivo combination therapy increased apoptotic markers as well as the intensity of HMGB1 staining compared to control (P < 0.05).

Conclusions

Our evidence suggests that sphingolipid metabolism is dysregulated in PDAC. Furthermore, S1P inhibition can sensitize PDAC to Oxa therapy through increasing ER stress and can potentiate ICD induction. This highlights a potential therapeutic target for chemosensitizing PDAC as well as an adjunct for future chemoimmunotherapy strategies.

Nanoparticles integrated with mild photothermal therapy and oxaliplatin for tumor chemotherapy and immunotherapy

Aims: Preparation and evaluation of nanoparticles for tumor chemotherapy and immunotherapy mild photothermal therapy and oxaliplatin. Methods: The double emulsion method was used for nanoparticle preparations. Polydopamine was deposited on the surface, which was further modified with folic acid. Cytotoxicity assays were carried out by cell counting kit-8. In vivo antitumor assays were carried out on 4T1 tumor-bearing mice. Results: The nanoparticles exhibited a 190 nm-diameter pomegranate-like sphere, which could increase temperature to 43-46°C. In vivo distribution showed enhanced accumulation. The nanoparticles generated stronger immunogenic cell death effects. By stimulating the maturation of dendritic cells, mild photothermal therapy combined with oxaliplatin significantly increased the antitumor effect by a direct killing effect and activation of immunotherapy. Conclusion: This study provided a promising strategy of combination therapy for tumors.

Immunogenic cell stress and death in the treatment of cancer

The successful treatment of oncological malignancies which results in long-term disease control or the complete eradication of cancerous cells necessitates the onset of adaptive immune responses targeting tumor-specific antigens. Such desirable anticancer immunity can be triggered via the induction of immunogenic cell death (ICD) of cancer cells, thus converting malignant cells into an in situ vaccine that elicits T cell mediated adaptive immune responses and establishes durable immunological memory. The exploration of ICD for cancer treatment has been subject to extensive research. However, functional heterogeneity among ICD activating therapies in many cases requires specific co-medications to achieve full-blown efficacy. Here, we described the hallmarks of ICD and classify ICD activators into three distinct functional categories namely, according to their mode of action: (i) ICD inducers, which increase the immunogenicity of malignant cells, (ii) ICD sensitizers, which prime cellular circuitries for ICD induction by conventional cytotoxic agents, and (iii) ICD enhancers, which improve the perception of ICD signals by antigen presenting dendritic cells. Altogether, ICD induction, sensitization and enhancement offer the possibility to convert well-established conventional anticancer therapies into immunotherapeutic approaches that activate T cell-mediated anticancer immunity.

Reinforced Immunogenic Endoplasmic Reticulum Stress and Oxidative Stress via an Orchestrated Nanophotoinducer to Boost Cancer Photoimmunotherapy

Cancer progression and treatment-associated cellular stress impairs therapeutic outcome by inducing resistance. Endoplasmic reticulum (ER) stress is responsible for core events. Aberrant activation of stress sensors and their downstream components to disrupt homeostasis have emerged as vital regulators of tumor progression as well as response to cancer therapy. Here, an orchestrated nanophotoinducer (ERsNP) results in specific tumor ER-homing, induces hyperthermia and mounting oxidative stress associated reactive oxygen species (ROS), and provokes intense and lethal ER stress upon near-infrared laser irradiation. The strengthened "dying" of ER stress and ROS subsequently induce apoptosis for both primary and abscopal B16F10 and GL261 tumors, and promote damage-associated molecular patterns to evoke stress-dependent immunogenic cell death effects and release "self-antigens". Thus, there is a cascade to activate maturation of dendritic cells, reprogram myeloid-derived suppressor cells to manipulate immunosuppression, and recruit cytotoxic T lymphocytes and effective antitumor response. The long-term protection against tumor recurrence is realized through cascaded combinatorial preoperative and postoperative photoimmunotherapy including the chemokine (C-C motif) receptor 2 antagonist, ERsNP upon laser irradiation, and an immune checkpoint inhibitor. The results highlight great promise of the orchestrated nanophotoinducer to exert potent immunogenic cell stress and death by reinforcing ER stress and oxidative stress to boost cancer photoimmunotherapy.

Combining theranostic/particle therapy with immunotherapy for the treatment of GU malignancies

Particle therapy and radiopharmaceuticals are emerging fields in the treatment of genitourinary cancers. With these novel techniques and the ever-growing immunotherapy options, the combinations of these therapies have the potential to improve current cancer cure rates. However, the most effective sequence and combination of these therapies is unknown and is a question that is actively being explored in multiple ongoing clinical trials. Here, we review the immunological effects of particle therapy and the available radiopharmaceuticals and discuss how best to combine these therapies.

Intratumoral Injection of Large Surface Area Microparticle Taxanes in Carcinomas Increases Immune Effector Cell Concentrations, Checkpoint Expression, and Synergy with Checkpoint Inhibitors: A Review of Preclinical and Clinical Studies

This review summarizes development of large surface area microparticle paclitaxel (LSAM-PTX) and docetaxel (LSAM-DTX) for local treatment of primary carcinomas with emphasis on immunomodulation. Intratumoral (IT) delivery of LSAM-PTX and LSAM-DTX provides continuous, therapeutic drug levels for several weeks. Preclinical studies and clinical trials reported a reduction in tumor volume (TV) and immunomodulation in primary tumor and peripheral blood with increases in innate and adaptive immune cells and decreases in suppressor cells. Increased levels of checkpoint expression of immune cells occurred in clinical trials of high-risk non-muscle-invasive bladder cancer (LSAM-DTX) and unresectable localized pancreatic cancer (LSAM-PTX). TV reduction and increases in immune effector cells occurred following IT LSAM-DTX and IT LSAM-PTX together with anti-mCTLA-4 and anti-mPD-1, respectively. Synergistic benefits from combinatorial therapy in a 4T1-Luc breast cancer model included reduction of metastasis with IT LSAM-DTX + anti-mCTLA-4. IT LSAM-PTX and LSAM-DTX are tumoricidal, immune enhancing, and may improve solid tumor response to immune checkpoint inhibitors without additional systemic toxicity.

Near-infrared photoimmunotherapy and anti-cancer immunity

The activation of the anti-cancer immune system is an important strategy to control cancer. A new form of cancer phototherapy, near-infrared photoimmunotherapy (NIR-PIT), was approved for clinical use in 2020 and uses IRDye® 700DX (IR700)-conjugated antibodies and NIR light. After irradiation with NIR light, the antibody-IR700 conjugate forms water-insoluble aggregations on the plasma membrane of target cells. This aggregation causes lethal damage to the plasma membrane, and effectively leads to immunogenic cell death (ICD). Subsequently, ICD activates anti-cancer immune cells such as dendritic cells and cytotoxic T cells. Combination therapy with immune-checkpoint blockade has synergistically improved the anti-cancer effects of NIR-PIT. Additionally, NIR-PIT can eliminate immunosuppressive immune cells in light-irradiated tumors by using specific antibodies against regulatory T cells and myeloid-derived suppressor cells. In addition to cancer-cell-targeted NIR-PIT, such immune-cell-targeted NIR-PIT has shown promising results by activating the anti-cancer immune system. Furthermore, NIR-PIT can be used to manipulate the tumor microenvironment by eliminating only targeted cells in the tumor, and thus it also can be used to gain insight into immunity in basic research.

Immunogenic cell death in colorectal cancer: a review of mechanisms and clinical utility

Colorectal cancer (CRC) is a major cause of cancer-related morbidity and mortality worldwide. Despite several clinical advances the survival of patients with advanced colorectal cancer remains limited, demanding newer approaches. The immune system plays a central role in cancer development, propagation, and treatment response. Within the bowel, the colorectal mucosa is a key barrier and site of immune regulation that is generally immunosuppressive. Nonetheless, within this tumour microenvironment, it is evident that anti-neoplastic treatments which cause direct cytotoxic and cytostatic effects may also induce immunogenic cell death (ICD), a form of regulated cell death that leads to an anti-tumour immune response. Therefore, novel ICD inducers and molecular biomarkers of ICD action are urgently needed to advance treatment options for advanced CRC. This article reviews our knowledge of ICD in CRC.

Design and Evaluation of Phosphonamidate-Linked Exatecan Constructs for Highly Loaded, Stable, and Efficacious Antibody-Drug Conjugates

Topoisomerase I (TOP1) Inhibitors constitute an emerging payload class to engineer antibody-drug conjugates (ADC) as next-generation biopharmaceutical for cancer treatment. Existing ADCs are using camptothecin payloads with lower potency and suffer from limited stability in circulation. With this study, we introduce a novel camptothecin-based linker-payload platform based on the highly potent camptothecin derivative exatecan. First, we describe general challenges that arise from the hydrophobic combination of exatecan and established dipeptidyl p-aminobenzyl-carbamate (PAB) cleavage sites such as reduced antibody conjugation yields and ADC aggregation. After evaluating several linker-payload structures, we identified ethynyl-phosphonamidates in combination with a discrete PEG24 chain to compensate for the hydrophobic PAB-exatecan moiety. Furthermore, we demonstrate that the identified linker-payload structure enables the construction of highly loaded DAR8 ADCs with excellent solubility properties. Head-to-head comparison with Enhertu, an approved camptothecin-based ADC, revealed improved target-mediated killing of tumor cells, excellent bystander killing, drastically improved linker stability in vitro and in vivo and superior in vivo efficacy over four tested dose levels in a xenograft model. Moreover, we show that ADCs based on the novel exatecan linker-payload platform exhibit antibody-like pharmacokinetic properties, even when the ADCs are highly loaded with eight drug molecules per antibody. This ADC platform constitutes a new and general solution to deliver TOP1 inhibitors with highest efficiency to the site of the tumor, independent of the antibody and its target, and is thereby broadly applicable to various cancer indications.

Systemic Delivery of Paclitaxel by Find-Me Nanoparticles Activates Antitumor Immunity and Eliminates Tumors

Local delivery of immune-activating agents has shown promise in overcoming an immunosuppressive tumor microenvironment (TME) and stimulating antitumor immune responses in tumors. However, systemic therapy is ultimately needed to treat tumors that are not readily locatable or accessible. To enable systemic delivery of immune-activating agents, we employ poly(lactic-co-glycolide) (PLGA) nanoparticles (NPs) with a track record in systemic application. The surface of PLGA NPs is decorated with adenosine triphosphate (ATP), a damage-associated molecular pattern to recruit antigen-presenting cells (APCs). The ATP-conjugated PLGA NPs (NPpD-ATP) are loaded with paclitaxel (PTX), a chemotherapeutic agent inducing immunogenic cell death to generate tumor antigens in situ. We show that the NPpD-ATP retains ATP activity in hostile TME and provides a stable "find-me" signal to recruit APCs. Therefore, the PTX-loaded NPpD-ATP helps populate antitumor immune cells in TME and attenuate the growth of CT26 and B16F10 tumors better than a mixture of PTX-loaded NPpD and ATP. Combined with anti-PD-1 antibody, PTX-loaded NPpD-ATP achieves complete regression of CT26 tumors followed by antitumor immune memory. This study demonstrates the feasibility of systemic immunotherapy using a PLGA NP formulation that delivers ICD-inducing chemotherapy and an immunostimulatory signal.

Trabectedin and low-dose radiation therapy in patients with advanced leiomyosarcoma

Background and objectives

Dimensional response is an unmet need in second lines of advanced soft tissue sarcomas (STS). Indeed, the three approved drugs, pazopanib, trabectedin, and eribulin, achieved an overall response rate (ORR) of less than 10%. This fact potentially hinders the options for fast symptomatic relief or surgical rescue. The combination of trabectedin plus low-dose radiation therapy (T-XRT) demonstrated a response rate of 60% in phase I/II trial, while real-life data achieved 32.5% ORR, probably due to a more relaxed timing between treatments. These results were obtained in progressing and advanced STS. In this study, the merged databases (trial plus real life) have been analyzed, with a special focus on leiomyosarcoma patients.

Design and methods

As responses were seen in a wide range of sarcoma histologies (11), this study planned to analyze whether leiomyosarcoma, the largest subtype with 26 cases (30.6%) in this series, exhibited a better clinical outcome with this therapeutic strategy. In addition, four advanced and progressing leiomyosarcoma patients, all with extraordinarily long progression-free survival of over 18 months, were collected.

Results

A total of 847 cycles of trabectedin were administered to 85 patients, with the median number of cycles per patient being 7 (1-45+). A trend toward a longer progression-free survival (PFS) was observed in leiomyosarcoma patients with median PFS (mPFS) of 9.9 months [95% confidence interval (CI): 1.1-18.7] versus 5.6 months (95% CI: 3.2-7.9) for the remaining histologies, p = 0.25. When leiomyosarcoma and liposarcoma were grouped, this difference reached statistical significance, probably due to the special sensitivity of myxoid liposarcoma. The mPFS for L-sarcomas was 12.7 months (95% CI: 7-18.5) versus 4.3 months (95% CI: 3.3-5.3) for the remaining histologies, p = 0.001. Cases with long-lasting disease control are detected among leiomyosarcoma patients.

Conclusion

Even when extraordinarily long-lasting responses do exist among leiomyosarcoma patients treated with T-XR, we were unable to demonstrate a significant difference favoring leiomyosarcoma patients in clinical outcomes.

Immunogenic cell death-related classification reveals prognosis and effectiveness of immunotherapy in breast cancer

Lack of specific biomarkers and effective drug targets constrains therapeutic research in breast cancer (BC). In this regard, therapeutic modulation of damage-associated molecular patterns (DAMPs)-induced immunogenic cell death (ICD) may help improve the effect of immunotherapy in individuals with BC. The aim of this investigation was to develop biomarkers for ICD and to construct ICD-related risk estimation models to predict prognosis and immunotherapy outcomes of BC. RNA-seq transcriptome information and medical data from individuals with BC (n = 943) were obtained from TCGA. Expression data from a separate BC cohort (GEO: GSE20685) were used for validation. We identified subtypes of high and low ICD gene expression by consensus clustering and assessed the connection between ICD subtypes and tumor microenvironment (TME). In addition, different algorithms were used to construct ICD-based prognostic models of BC. BC samples were categorized into subtypes of high and low ICD expression depending on the expression of genes correlated with ICD. The subtype of ICD high-expression subtypes are correlated with poor prognosis in breast cancer, while ICD low-expression subtypes may predict better clinical outcomes. We also created and verified a predictive signature model depending on four ICD-related genes (ATG5, CD8A, CD8B, and HSP90AA1), which correlates with TME status and predicts clinical outcomes of BC patients. We highlight the connection of ICD subtypes with the dynamic evolution of TME in BC and present a novel ICD-based prognostic model of BC. In clinical practice, distinction of ICD subtype and assessment of ICD-related biomarkers should help guide treatment planning and improve the effectiveness of tumor immunotherapy.

Oncolytic Virotherapy: A New Paradigm in Cancer Immunotherapy

Oncolytic viruses (OVs) are emerging as potential treatment options for cancer. Natural and genetically engineered viruses exhibit various antitumor mechanisms. OVs act by direct cytolysis, the potentiation of the immune system through antigen release, and the activation of inflammatory responses or indirectly by interference with different types of elements in the tumor microenvironment, modification of energy metabolism in tumor cells, and antiangiogenic action. The action of OVs is pleiotropic, and they show varied interactions with the host and tumor cells. An important impediment in oncolytic virotherapy is the journey of the virus into the tumor cells and the possibility of its binding to different biological and nonbiological vectors. OVs have been demonstrated to eliminate cancer cells that are resistant to standard treatments in many clinical trials for various cancers (melanoma, lung, and hepatic); however, there are several elements of resistance to the action of viruses per se. Therefore, it is necessary to evaluate the combination of OVs with other standard treatment modalities, such as chemotherapy, immunotherapy, targeted therapies, and cellular therapies, to increase the response rate. This review provides a comprehensive update on OVs, their use in oncolytic virotherapy, and the future prospects of this therapy alongside the standard therapies currently used in cancer treatment.