Immunogenic cell death-based cancer vaccines: promising prospect in cancer therapy.

Tumor immunotherapy is a promising approach for addressing the limitations of conventional tumor treatments, such as chemotherapy and radiotherapy, which often have side effects and fail to prevent recurrence and metastasis. However, the effectiveness and sustainability of immune activation in tumor immunotherapy remain challenging. Tumor immunogenic cell death, characterized by the release of immunogenic substances, damage associated molecular patterns (DAMPs), and tumor associated antigens, from dying tumor cells (DTCs), offers a potential solution. By enhancing the immunogenicity of DTCs through the inclusion of more immunogenic antigens and stimulating factors, immunogenic cell death (ICD) based cancer vaccines can be developed as a powerful tool for immunotherapy. Integrating ICD nanoinducers into conventional treatments like chemotherapy, photodynamic therapy, photothermal therapy, sonodynamic therapy, and radiotherapy presents a novel strategy to enhance treatment efficacy and potentially improve patient outcomes. Preclinical research has identified numerous potential ICD inducers. However, effectively translating these findings into clinically relevant applications remains a critical challenge. This review aims to contribute to this endeavor by providing valuable insights into the in vitro preparation of ICD-based cancer vaccines. We explored established tools for ICD induction, followed by an exploration of personalized ICD induction strategies and vaccine designs. By sharing this knowledge, we hope to stimulate further development and advancement in the field of ICD-based cancer vaccines.

Targeted Drug Delivery by MMAE Farnesyl-Bioconjugated Multivalent Chemically Self-Assembled Nanorings Induces Potent Receptor-Dependent Immunogenic Cell Death.

Antibody-drug conjugates, nanoparticles, and liposomes have been used for anticancer drug delivery. The success of targeted killing of cancer cells relies heavily on the selectivity of the drug delivery systems. In most systems, antibodies or their fragments were used as targeting ligands. In this study, we have investigated the potential for protein-based octomeric chemically self-assembled nanorings (CSANs) to be used for anticancer drug delivery. The CSANs are composed of a DHFR-DHFR fusion protein incorporating an EGFR-targeting fibronectin and the anticancer drug MMAE conjugated through a C-terminal farnesyl azide. The anti-EGFR-MMAE CSANs were shown to undergo rapid internalization and have potent cytotoxicity to cancer cells across a 9000-fold difference in EGFR expression. In addition, anti-EGFR-MMAE CSANs were shown to induce immunological cell death. Thus, multivalent and modular CSANs are a potential alternative anticancer drug delivery platform with the capability of targeting tumor cells with heterogeneous antigen expression while activating the anticancer immune response.

Genetically Edited Cascade Nanozymes for Cancer Immunotherapy.

Immune checkpoint blockade (ICB) has brought tremendous clinical progress, but its therapeutic outcome can be limited due to insufficient activation of dendritic cells (DCs) and insufficient infiltration of cytotoxic T lymphocytes (CTLs). Evoking immunogenic cell death (ICD) is one promising strategy to promote DC maturation and elicit T-cell immunity, whereas low levels of ICD induction of solid tumors restrict durable antitumor efficacy. Herein, we report a genetically edited cell membrane-coated cascade nanozyme (gCM@MnAu) for enhanced cancer immunotherapy by inducing ICD and activating the stimulator of the interferon genes (STING) pathway. In the tumor microenvironment (TME), the gCM@MnAu initiates a cascade reaction and generates abundant cytotoxic hydroxyl (•OH), resulting in improved chemodynamic therapy (CDT) and boosted ICD activation. In addition, released Mn2+ during the cascade reaction activates the STING pathway and further promotes the DC maturation. More importantly, activated immunogenicity in the TME significantly improves gCM-mediated PD-1/PD-L1 checkpoint blockade therapy by eliciting systemic antitumor responses. In breast cancer subcutaneous and lung metastasis models, the gCM@MnAu showed synergistically enhanced therapeutic effects and significantly prolonged the survival of mice. This work develops a genetically edited nanozyme-based therapeutic strategy to improve DC-mediated cross-priming of T cells against poorly immunogenic solid tumors.

Nanoparticle-mediated immunogenic cell death for cancer immunotherapy.

The field of cancer therapy is witnessing the emergence of immunotherapy, an innovative approach that activates the body own immune system to combat cancer. Immunogenic cell death (ICD) has emerged as a prominent research focus in the field of cancer immunotherapy, attracting significant attention in recent years. The activation of ICD can induce the release of damage-associated molecular patterns (DAMPs), such as calreticulin (CRT), adenosine triphosphate (ATP), high mobility group box protein 1 (HMGB1), and heat shock proteins (HSP). Subsequently, this process promotes the maturation of innate immune cells, including dendritic cells (DCs), thereby triggering a T cell-mediated anti-tumor immune response. The activation of the ICD ultimately leads to the development of long-lasting immune responses against tumors. Studies have demonstrated that partial therapeutic approaches, such as chemotherapy with doxorubicin, specific forms of radiotherapy, and phototherapy, can induce the generation of ICD. The main focus of this article is to discuss and review the therapeutic methods triggered by nanoparticles for ICD, while briefly outlining their anti-tumor mechanism. The objective is to provide a comprehensive reference for the widespread application of ICD.

The Ability of Clinically Relevant Chemotherapeutics to Induce Immunogenic Cell Death in Squamous Cell Carcinoma.

BACKGROUND: Immunogenic cell death (ICD) is a crucial mechanism for triggering the adaptive immune response in cancer patients. Damage-associated molecular patterns (DAMPs) are critical factors in the detection of ICD. Chemotherapeutic drugs can cause ICD and the release of DAMPs. The aim of this study was to assess the potential for paclitaxel and platinum-based chemotherapy regimens to induce ICD in squamous cell carcinoma (SCC) cell lines. In addition, we examined the immunostimulatory effects of clinically relevant chemotherapeutic regimens utilized in the treatment of SCC. METHODS: We screened for differentially expressed ICD markers in the supernatants of three SCC cell lines following treatment with various chemotherapeutic agents. The ICD markers included Adenosine Triphosphate (ATP), Calreticulin (CRT), Annexin A1 (ANXA 1), High Mobility Group Protein B1 (HMGB1), and Heat Shock Protein 70 (HSP70). A vaccination assay was also employed in C57BL/6J mice to validate our in vitro findings. Lastly, the levels of CRT and HMGB1 were evaluated in Serum samples from SCC patients. RESULTS: Addition of the chemotherapy drugs cisplatin (DDP), carboplatin (CBP), nedaplatin (NDP), oxaliplatin (OXA) and docetaxel (DOC) increased the release of ICD markers in two of the SCC cell lines. Furthermore, mice that received vaccinations with cervical cancer cells treated with DDP, CBP, NDP, OXA, or DOC remained tumor-free. Although CBP induced the release of ICD-associated molecules in vitro, it did not prevent tumor growth at the vaccination site in 40% of mice. In addition, both in vitro and in vivo results showed that paclitaxel (TAX) and LBP did not induce ICD in SCC cells. CONCLUSION: The present findings suggest that chemotherapeutic agents can induce an adjuvant effect leading to the extracellular release of DAMPs. Of the agents tested here, DDP, CBP, NDP, OXA and DOC had the ability to act as inducers of ICD.

Tigilanol tiglate is an oncolytic small molecule that induces immunogenic cell death and enhances the response of both target and non-injected tumors to immune checkpoint blockade.

BACKGROUND: Tigilanol tiglate (TT) is a protein kinase C (PKC)/C1 domain activator currently being developed as an intralesional agent for the treatment of various (sub)cutaneous malignancies. Previous work has shown that intratumoral (I.T.) injection of TT causes vascular disruption with concomitant tumor ablation in several preclinical models of cancer, in addition to various (sub)cutaneous tumors presenting in the veterinary clinic. TT has completed Phase I dose escalation trials, with some patients showing signs of abscopal effects. However, the exact molecular details underpinning its mechanism of action (MoA), together with its immunotherapeutic potential in oncology remain unclear. METHODS: A combination of microscopy, luciferase assays, immunofluorescence, immunoblotting, subcellular fractionation, intracellular ATP assays, phagocytosis assays and mixed lymphocyte reactions were used to probe the MoA of TT in vitro. In vivo studies with TT used MM649 xenograft, CT-26 and immune checkpoint inhibitor refractory B16-F10-OVA tumor bearing mice, the latter with or without anti-programmed cell death 1 (PD-1)/anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) mAb treatment. The effect of TT at injected and non-injected tumors was also assessed. RESULTS: Here, we show that TT induces the death of endothelial and cancer cells at therapeutically relevant concentrations via a caspase/gasdermin E-dependent pyroptopic pathway. At therapeutic doses, our data demonstrate that TT acts as a lipotoxin, binding to and promoting mitochondrial/endoplasmic reticulum (ER) dysfunction (leading to unfolded protein responsemt/ER upregulation) with subsequent ATP depletion, organelle swelling, caspase activation, gasdermin E cleavage and induction of terminal necrosis. Consistent with binding to ER membranes, we found that TT treatment promoted activation of the integrated stress response together with the release/externalization of damage-associated molecular patterns (HMGB1, ATP, calreticulin) from cancer cells in vitro and in vivo, characteristics indicative of immunogenic cell death (ICD). Confirmation of ICD in vivo was obtained through vaccination and rechallenge experiments using CT-26 colon carcinoma tumor bearing mice. Furthermore, TT also reduced tumor volume, induced immune cell infiltration, as well as improved survival in B16-F10-OVA tumor bearing mice when combined with immune checkpoint blockade. CONCLUSIONS: These data demonstrate that TT is an oncolytic small molecule with multiple targets and confirms that cell death induced by this compound has the potential to augment antitumor responses to immunotherapy.

NIR-responsive copper nanoliposome composites for cascaded ferrotherapy via ferroptosis actived ICD and IFN-γ released.

Metallic biomaterials activate tumor ferroptosis by increasing oxidative stress, but their efficacy is severely limited in tumor microenvironment. Although interferon gamma (IFN-γ) can promote tumor ferroptosis sensitivity by inhibiting the antioxidant system and promoting lipid accumulation, this effect limited by the lack of IFN-γ accumulation in tumors. Herein, we report a near-infrared (NIR)-responsive HCuS nanocomposite (HCuS-PE@TSL-tlyp-1) that can stimulate immunogenic cell death (ICD)-mediated IFN-γ secretion through exogenous oxidative stress, thereby achieving cascaded ferrotherapy by mutually reinforcing ferroptosis and systemic immunity. Upon laser irradiation, the dissolution of the thermal coating, and the introduction of Cu ions and piperazine-erastin (PE) simultaneously induce oxidative stress by reactive oxygen species (ROS)/lipid peroxide (LPO) accumulation and deplete cystine-glutamate transporter (xCT)/GSH. The onset of oxidative stress-mediated ferroptosis is thus achieved, and ICD is triggered, significantly promoting cytotoxic T-cell (CTL) infiltration for IFN-γ secretion. Furthermore, IFN-γ induces immunogenic tumor ferroptosis by inhibiting xCT-antioxidant pathways and enhancing the ACSL4-fatty acid recruitment pathway, which further promotes sensitivity to ferroptosis in cells. These HCuS nanocomposites combined with aPD-L1 effectively in inhibiting tumor metastasis and recurrence. Importantly, these cascade ferrotherapy results broadens the application of HCuS biomaterials.

Investigation of folate-modified EGCG-loaded thermosensitive nanospheres inducing immunogenic cell death and damage-associated molecular patterns in hepatocellular carcinoma.

BACKGROUND: The systemic treatment of advanced hepatocellular carcinoma is currently facing a bottleneck. EGCG, the primary active compound in green tea, exhibits anti-tumor effects through various pathways. However, there is a lack of study on EGCG-induced immunogenic cell death (ICD) in hepatocellular carcinoma. METHODS: In a previous study, we successfully synthesized folate-modified thermosensitive nano-materials, encapsulated EGCG within nanoparticles using a hydration method, and established the EGCG nano-drug delivery system. The viability of HepG2 cells post-EGCG treatment was assessed via the MTT and EdU assays. Cell migration and invasion were evaluated through wound healing experiments, Transwell assays, and Annexin V-FITC/PI assay for apoptosis detection. Additionally, the expression levels of damage-associated molecular patterns (DAMPs) were determined using immunofluorescence, ATP measurement, RT-qPCR, and Western Blot. RESULTS: The drug sensitivity test revealed an IC50 value of 96.94 µg/mL for EGCG in HepG2 cells after 48 h. EGCG at a low concentration (50 µg/mL) significantly impeded the migration and invasion of HepG2 cells, showing a clear dose-dependent response. Moreover, medium to high EGCG concentrations induced cell apoptosis in a dose-dependent manner and upregulated DAMPs expression. Immunofluorescence analysis demonstrated a notable increase in CRT expression following low-concentration EGCG treatment. As EGCG concentration increased, cell viability decreased, leading to CRT exposure on the cell membrane. EGCG also notably elevated ATP levels. RT-qPCR and Western Blot analyses indicated elevated expression levels of HGMB1, HSP70, and HSP90 following EGCG intervention. CONCLUSION: EGCG not only hinders the proliferation, migration, and invasion of hepatocellular carcinoma cells and induces apoptosis, but also holds significant clinical promise in the treatment of malignant tumors by promoting ICD and DAMPs secretion.

Turning anecdotal irradiation-induced anticancer immune responses into reproducible in situ cancer vaccines via disulfiram/copper-mediated enhanced immunogenic cell death of breast cancer cells.

Irradiation (IR) induces immunogenic cell death (ICD) in tumors, but it rarely leads to the abscopal effect (AE); even combining IR with immune checkpoint inhibitors has shown only anecdotal success in inducing AEs. In this study, we aimed to enhance the IR-induced immune response and generate reproducible AEs using the anti-alcoholism drug, disulfiram (DSF), complexed with copper (DSF/Cu) to induce tumor ICD. We measured ICD in vitro and in vivo. In mouse tumor models, DSF/Cu was injected intratumorally followed by localized tumor IR, creating an in situ cancer vaccine. We determined the anticancer response by primary tumor rejection and assessed systemic immune responses by tumor rechallenge and the occurrence of AEs relative to spontaneous lung metastasis. In addition, we analyzed immune cell subsets and quantified proinflammatory and immunosuppressive chemokines/cytokines in the tumor microenvironment (TME) and blood of the vaccinated mice. Immune cell depletion was investigated for its effects on the vaccine-induced anticancer response. The results showed that DSF/Cu and IR induced more potent ICD under hypoxia than normoxia in vitro. Low-dose intratumoral (i.t.) injection of DSF/Cu and IR(12Gy) demonstrated strong anti-primary and -rechallenged tumor effects and robust AEs in mouse models. These vaccinations also increased CD8+ and CD4+ cell numbers while decreasing Tregs and myeloid-derived suppressor cells in the 4T1 model, and increased CD8+, dendritic cells (DC), and decreased Treg cell numbers in the MCa-M3C model. Depleting both CD8+ and CD4+ cells abolished the vaccine's anticancer response. Moreover, vaccinated tumor-bearing mice exhibited increased TNFα levels and reduced levels of immunosuppressive chemokines/cytokines. In conclusion, our novel approach generated an anticancer immune response that results in a lack of or low tumor incidence post-rechallenge and robust AEs, i.e., absence of or decreased spontaneous lung metastasis in tumor-bearing mice. This approach is readily translatable to clinical settings and may increase IR-induced AEs in cancer patients.

Immunostimulatory effects of thermal ablation: Challenges and future prospects.

ABSTRACT: This literature explores the immunostimulatory effects of thermal ablation in the tumor microenvironment, elucidating the mechanisms such as immunogenic cell death, tumor-specific antigens, and damage-associated molecular patterns. Furthermore, it outlines critical issues associated with thermal ablation-induced immunostimulatory challenges and offers insights into future research avenues and potential therapeutic strategies.

Arsenic trioxide augments immunogenic cell death and induces cGAS-STING-IFN pathway activation in hepatocellular carcinoma.

The treatment of hepatocellular carcinoma (HCC) is particularly challenging due to the inherent tumoral heterogeneity and easy resistance towards chemotherapy and immunotherapy. Arsenic trioxide (ATO) has emerged as a cytotoxic agent effective for treating solid tumors, including advanced HCC. However, its effectiveness in HCC treatment remains limited, and the underlying mechanisms are still uncertain. Therefore, this study aimed to characterize the effects and mechanisms of ATO in HCC. By evaluating the susceptibilities of human and murine HCC cell lines to ATO treatment, we discovered that HCC cells exhibited a range of sensitivity to ATO treatment, highlighting their inherent heterogeneity. A gene signature comprising 265 genes was identified to distinguish ATO-sensitive from ATO-insensitive cells. According to this signature, HCC patients have also been classified and exhibited differential features of ATO response. Our results showed that ATO treatment induced reactive oxygen species (ROS) accumulation and the activation of multiple cell death modalities, including necroptosis and ferroptosis, in ATO-sensitive HCC cells. Meanwhile, elevated tumoral immunogenicity was also observed in ATO-sensitive HCC cells. Similar effects were not observed in ATO-insensitive cells. We reported that ATO treatment induced mitochondrial injury and mtDNA release into the cytoplasm in ATO-sensitive HCC tumors. This subsequently activated the cGAS-STING-IFN axis, facilitating CD8+ T cell infiltration and activation. However, we found that the IFN pathway also induced tumoral PD-L1 expression, potentially antagonizing ATO-mediated immune attack. Additional anti-PD1 therapy promoted the anti-tumor response of ATO in ATO-sensitive HCC tumors. In summary, our data indicate that heterogeneous ATO responses exist in HCC tumors, and ATO treatment significantly induces immunogenic cell death (ICD) and activates the tumor-derived mtDNA-STING-IFN axis. These findings may offer a new perspective on the clinical treatment of HCC and warrant further study.

PI3Kα inhibitor GNE-493 triggers antitumor immunity in murine lung cancer by inducing immunogenic cell death and activating T cells.

Phosphatidylinositol 3-kinase (PI3K) is frequently hyperactivated in cancer, playing pivotal roles in the pathophysiology of both malignant and immune cells. The impact of PI3K inhibitors on the tumor microenvironment (TME) within lung cancer remains largely unknown. In this study, we explored the regulatory effects of GNE-493, an innovative dual inhibitor of PI3K and mammalian target of rapamycin (mTOR), on the TME of lung cancer. First, through the analysis of The Cancer Genome Atlas-lung squamous cell carcinoma (LUSC) cohort, we found PIK3CA to be related to CD8 T cells, which may affect the overall survival rate of patients by affecting CD8 function. We herein demonstrated that GNE-493 can significantly inhibit tumor cell proliferation and promote cell apoptosis while increasing the expression of the immunogenic death-related molecules CRT and HSP70 using in vitro cell proliferation and apoptosis experiments on the murine KP lung cancer cell line and human A549 lung cancer cell line. Next, through the establishment of an orthotopic tumor model in vivo, it was found that after GNE-493 intervention, the infiltration of CD4+ and CD8+ T cells in mouse lung tumor was significantly increased, and the expression of CRT in tumors could be induced to increase. To explore the mechanisms underlying PI3K inhibition-induced changes in the TME, the gene expression differences of T cells in the control group versus GNE-493-treated KP tumors were analyzed by RNA-seq, and the main effector pathway of anti-tumor immunity was identified. The IFN/TNF family molecules were significantly upregulated after GNE-493 treatment. In summary, our findings indicate that GNE-493 promotes immunogenic cell death in lung cancer cells, and elucidates its regulatory impact on molecules associated with the adaptive immune response. Our study provides novel insights into how PI3K/mTOR inhibitors exert their activity by modulating the tumor-immune interaction.

Combining cisplatin with Pinellia pedatisecta Schott lipid-soluble extract induces tumor immunogenic cell death in cervical cancer.

BACKGROUND: Pinellia pedatisecta Schott extract (PE) is extracted from Pinellia pedatisecta Schott (PPS), a traditional Chinese medicinal plant with the potential for direct anticancer effects or eliciting an anti-tumor response by activating the immune system. PURPOSE: To explore PE's ability and mechanism to reconstruct cisplatin's immunogenicity. METHODS: Cervical cancer cells were treated with cisplatin (CDDP) and/or PE. The exposure of calreticulin (CRT) on cell membrane was investigated by flow cytometry. The extracellular of ATP and HMGB1 was investigated by Western blot analysis, immunofluorescence and ELISA assay. Changes in immune profiles were using flow cytometry in vaccination and anti-tumor assays in vivo. Lastly, the mechanism of PE influenced the ROS/ERS pathway was examined by ROS assay kit, flow cytometry and Western blotting. RESULTS: PE treatment induced translocation of CRT from the endoplasmic reticulum to the cell membrane of tumor cells, concomitantly triggering immunogenic cell death (ICD). In terms of mechanisms, endoplasmic reticulum (ER) stress relievers could impede the ability of PE to induce immunogenicity. This indicates that PE is activated by ER stress, leading to subsequent induction of ICD. Upon analyzing RNA-seq data, it was observed that PE primarily induces programmed cell death in tumors by impeding upstream antioxidant mechanisms. Additionally, it transforms dying tumor cells into vaccines, activating a series of immune responses. CONCLUSIONS: This study observed for the first time that PE-induced CRT exposure on the membrane of cervical cancer cells compensates for the defect of nonimmunogenic cell death inducer CDDP thereby stimulating potent ICD. This ability restores the immunogenicity of CDDP through ER stress induced by the ROS signal. ROS played a role in PE's ability to induce ICD, leading to increased expression of ER stress-related proteins, including ATF3 and IRE-1α. PE exerted anti-cancer effects by increasing the ROS levels, and ROS/ERS signaling may be a potential avenue for cervical cancer treatment. Hence, the synergistic use of PE and CDDP holds potential for enhancing immunochemotherapy in cancer treatment.

The copper (II) complex of salicylate phenanthroline induces immunogenic cell death of colorectal cancer cells through inducing endoplasmic reticulum stress.

BACKGROUND: In our previous study, Cu(sal)phen was found to have anti-tumor effects, yet its precise mechanism remains unknown. Research has shown that dying tumor cells release damage-associated molecular patterns (DAMPs) to promote anti-tumor immune response. Therefore, we have further explored the effects and potential molecular mechanisms of Cu(sal)phen-induced immunogenic cell death (ICD) in colorectal cancer (CRC). METHODS: ELISA and flow cytometry were used to detect the effects of Cu(sal)phen treatment on ICD markers. The molecular mechanisms of Cu(sal)phen-induced ICD were investigated through the detection of endoplasmic reticulum stress (ERS) and reactive oxygen species (ROS) in vitro using Western blot and flow cytometry. Additionally, a mouse model was constructed to study the effects of Cu(sal)phen on immune cells and anti-tumor-related cytokines in vivo. RESULTS: Cu(sal)phen induced the release of calreticulin (CRT), adenosine triphosphate (ATP) and high mobility group box 1 (HMGB1), the main molecular markers of ICD, by promoting the accumulation of ROS and inducing ERS. Furthermore, Cu(sal)phen promoted the maturation of dendritic cells (DCs) and activation of CD8+T cells, as well as the secretion of interleukin-12 (IL-12) and interferon-γ (IFN-γ), while downregulating transforming growth factor-ß (TGF-ß) levels, thereby activating the anti-tumor immune response. CONCLUSION: Cu(sal)phen has the potential to induce ICD in tumors and activate the adaptive immune response to achieve anti-tumor effects. This makes Cu(sal)phen a promising candidate for the treatment of CRC.

Peptide-Driven Proton Sponge Nano-Assembly for Imaging and Triggering Lysosome-Regulated Immunogenic Cancer Cell Death.

Triggering lysosome-regulated immunogenic cell death (ICD, e.g., pyroptosis and necroptosis) with nanomedicines is an emerging approach for turning an "immune-cold" tumor "hot"-a key challenge faced by cancer immunotherapies. Proton sponge such as high-molecular-weight branched polyethylenimine (PEI) is excellent at rupturing lysosomes, but its therapeutic application is hindered by uncontrollable toxicity due to fixed charge density and poor understanding of resulted cell death mechanism. Here, a series of proton sponge nano-assemblies (PSNAs) with self-assembly controllable surface charge density and cell cytotoxicity are created. Such PSNAs are constructed via low-molecular-weight branched PEI covalently bound to self-assembling peptides carrying tetraphenylethene pyridinium (PyTPE, an aggregation-induced emission-based luminogen). Assembly of PEI assisted by the self-assembling peptide-PyTPE leads to enhanced surface positive charges and cell cytotoxicity of PSNA. The self-assembly tendency of PSNAs is further optimized by tuning hydrophilic and hydrophobic components within the peptide, thus resulting in the PSNA with the highest fluorescence, positive surface charge density, cell uptake, and cancer cell cytotoxicity. Systematic cell death mechanistic studies reveal that the lysosome rupturing-regulated pyroptosis and necroptosis are at least two causes of cell death. Tumor cells undergoing PSNA-triggered ICD activate immune cells, suggesting the great potential of PSNAs to trigger anticancer immunity.

Controlled Refolding of Denatured IL-12 Using In Situ Antigen-Capturing Nanochaperone Remarkably Reduces the Systemic Toxicity and Enhances Cancer Immunotherapy.

Cytokines are powerful in cancer immunotherapy, however, their therapeutic potential is limited by the severe systemic toxicity. Here a potent strategy to reduce the toxicity of systemic cytokine therapy by delivering its denatured form using a finely designed nanochaperone, is described. It is demonstrated that even if the denatured protein cargos are occasionally released under normal physiological conditions they are still misfolded, while can effectively refold into native states and release to function in tumor microenvironment. Consequently, the systemic toxicity of cytokines is nearly completely overcome. Moreover, an immunogenic cell death (ICD)-inducing chemotherapeutic is further loaded and delivered to tumor using this nanochaperone to trigger the release of tumor-associated antigens (TAAs) that are subsequently captured in situ by nanochaperone and then reflows into lymph nodes (LNs) to promote antigen cross-presentation. This optimized personalized nanochaperone-vaccine demonstrates unprecedented suppressive effects against large, advanced tumors, and in combination with immune checkpoint blockade (ICB) therapy results in a significant abscopal effect and inhibition of postoperative tumor recurrence and metastasis. Hence, this approach provides a simple and universal delivery strategy to reduce the systemic toxicities of cytokines, as well as provides a robust personalized cancer vaccination platform, which may find wide applications in cancer immunotherapy.

Targeting TACC3 Induces Immunogenic Cell Death and Enhances T-DM1 Response in HER2-Positive Breast Cancer.

Trastuzumab emtansine (T-DM1) was the first and one of the most successful antibody-drug conjugates (ADC) approved for treating refractory HER2-positive breast cancer. Despite its initial clinical efficacy, resistance is unfortunately common, necessitating approaches to improve response. Here, we found that in sensitive cells, T-DM1 induced spindle assembly checkpoint (SAC)-dependent immunogenic cell death (ICD), an immune-priming form of cell death. The payload of T-DM1 mediated ICD by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which were lost in resistance. Accordingly, ICD-related gene signatures in pretreatment samples correlated with clinical response to T-DM1-containing therapy, and increased infiltration of antitumor CD8+ T cells in posttreatment samples was correlated with better T-DM1 response. Transforming acidic coiled-coil containing 3 (TACC3) was overexpressed in T-DM1-resistant cells, and T-DM1 responsive patients had reduced TACC3 protein expression whereas nonresponders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacologic inhibition of TACC3 restored T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition in vivo elicited ICD in a vaccination assay and potentiated the antitumor efficacy of T-DM1 by inducing dendritic cell maturation and enhancing intratumoral infiltration of cytotoxic T cells. Together, these results illustrate that ICD is a key mechanism of action of T-DM1 that is lost in resistance and that targeting TACC3 can restore T-DM1-mediated ICD and overcome resistance. SIGNIFICANCE: Loss of induction of immunogenic cell death in response to T-DM1 leads to resistance that can be overcome by targeting TACC3, providing an attractive strategy to improve the efficacy of T-DM1.

Simultaneous Activation of Immunogenic Cell Death and cGAS-STING Pathway by Liver- and Mitochondria-Targeted Gold(I) Complexes for Chemoimmunotherapy of Hepatocellular Carcinoma.

Induction of immunogenic cell death (ICD) and activation of the cyclic GMP-AMP synthase stimulator of interferon gene (cGAS-STING) pathway are two potent anticancer immunotherapeutic strategies in hepatocellular carcinoma (HCC). Herein, 12 liver- and mitochondria-targeting gold(I) complexes (9a-9l) were designed and synthesized. The superior complex 9b produced a considerable amount of reactive oxygen species (ROS) and facilitated DNA excretion, the ROS-induced ICD and DNA activated the cGAS-STING pathway, both of which evoked an intense anticancer immune response in vitro and in vivo. Importantly, 9b strongly inhibited tumor growth in a patient-derived xenograft model of HCC. Overall, we present the first case of simultaneous ICD induction and cGAS-STING pathway activation within the same gold-based small molecule, which may provide an innovative strategy for designing chemoimmunotherapies for HCC.

LW-213 induces immunogenic tumor cell death via ER stress mediated by lysosomal TRPML1.

Dying tumor cells release biological signals that exhibit antigenicity, activate cytotoxic T lymphocytes, and induce immunogenic cell death (ICD), playing a key role in immune surveillance. We demonstrate that the flavonoid LW-213 activates endoplasmic reticulum stress (ERS) in different tumor cells and that the lysosomal calcium channel TRPML1 mediates the ERS process in human cellular lymphoma Hut-102 cells. Apoptotic tumor cells induced by ERS often possess immunogenicity. Tumor cells treated with LW-213 exhibit damage-associated molecular patterns (DAMPs), including calreticulin translocation to the plasma membrane and extracellular release of ATP and HMGB1. When co-cultured with antigen-presenting cells (APCs), LW-213-treated tumor cells activated APCs. Two groups of C57BL/6J mice were inoculated with Lewis cells: a "vaccine group", which demonstrated that LW-213-treated tumor cells promote the maturation of dendritic cells and increase CD8+ T cells infiltration in the tumor microenvironment and a "pharmacodynamic group", treated with a combination of LW-213 and PD1/PD-L1 inhibitor (BMS-1), which reduced tumor growth and significantly prolonged the survival time of mice in the "pharmacodynamic group". Therefore, LW-213 can be developed as a novel ICD inducer, providing a new concept for antitumor immunotherapy.

Pt(II)-NHC Complex Induces ROS-ERS-Related DAMP Balance to Harness Immunogenic Cell Death in Hepatocellular Carcinoma.

Immunogenic cell death (ICD) can engage a specific immune response and establish a long-term immunity in hepatocellular carcinoma (HCC). Herein, we design and synthesize a series of Pt(II)-N-heterocyclic carbene (Pt(II)-NHC) complexes derived from 4,5-diarylimidazole, which show strong anticancer activities in vitro. Among them, 2c displays much higher anticancer activities than cisplatin and other Pt(II)-NHC complexes, especially in HCC cancer cells. In addition, we find that 2c is a type II ICD inducer, which can successfully induce endoplasmic reticulum stress (ERS) accompanied by reactive oxygen species (ROS) generation and finally lead to the release of damage-associated molecular patterns (DAMPs) in HCC cells. Importantly, 2c shows a great anti-HCC potential in a vaccination mouse model and leads to the in vivo immune cell activation in the CCl4-induced liver injury model.