Detection of immunogenic cell death and its relevance for cancer therapy

Advances in therapeutic cancer vaccines: Harnessing immune adjuvants for enhanced efficacy and future perspectives

Preventive cancer vaccines are highly effective in preventing viral infection-induced cancer, but advances in therapeutic cancer vaccines with a focus on eliminating cancer cells through immunotherapy are limited. To develop therapeutic cancer vaccines, the integration of optimal adjuvants is a potential strategy to enhance or complement existing therapeutic approaches. However, conventional adjuvants do not satisfy the criteria of clinical trials for therapeutic cancer vaccines. To improve the effects of adjuvants in therapeutic cancer vaccines, effective vaccination strategies must be formulated and novel adjuvants must be identified. This review offers an overview of the current advancements in therapeutic cancer vaccines and highlights in situ vaccination approaches that can be synergistically combined with other immunotherapies by harnessing the adjuvant effects. Additionally, the refinement of adjuvant systems using cutting-edge technologies and the elucidation of molecular mechanisms underlying immunogenic cell death to facilitate the development of innovative adjuvants have been discussed.

Discovery of novel quinoline scaffold selective estrogen receptor degraders (SERDs) for treatment of ER positive breast cancer with enhanced antiproliferative bioactivity through immunogenic cell death (ICD) effects

Combination therapy proven to be an effective therapeutic approach for estrogen receptor (ER)-positive breast cancer. Currently, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are combined with aromatase inhibitors (AIs) or selective estrogen receptor degraders (SERDs) as first-line therapy for advanced ER-positive breast cancer. Herein, a new family of quinoline scaffold SERDs was synthesized and evaluated in MCF-7 cells. Among them, compounds 18j and 24d exhibited remarkable MCF-7 inhibition, both alone and in combination with ribociclib (CDK4/6 inhibitor), in vitro and in vivo. Meanwhile, compounds 18j and 24d effectively degraded ER and inhibited ER downstream signaling pathways. Interestingly, compounds 18j and 24d induced endoplasmic reticulum stress (ERS) and triggered immunogenic cell death (ICD) via damage-associated molecular patterns (DAMPs) in MCF-7 cells. These findings highlight the immune-related and enhanced antiproliferative effects of oral SERDs in ER positive breast cancer treatment.

Turning foes to friends: Advanced "in situ nanovaccine" with dual immunoregulation for enhanced immunotherapy of metastatic triple-negative breast cancer

As a "cold tumor", triple-negative breast cancer (TNBC) exhibits limited responsiveness to current immunotherapy. How to enhance the immunogenicity and reverse the immunosuppressive microenvironment of TNBC remain a formidable challenge. Herein, an "in situ nanovaccine" Au/CuNDs-R848 was designed for imaging-guided photothermal therapy (PTT)/chemodynamic therapy (CDT) synergistic therapy to trigger dual immunoregulatory effects on TNBC. On the one hand, Au/CuNDs-R848 served as a promising photothermal agent and nanozyme, achieving PTT and photothermal-enhanced CDT against the primary tumor of TNBC. Meanwhile, the released antigens and damage-associated molecular patterns (DAMPs) promoted the maturation of dendritic cells (DCs) and facilitated the infiltration of T lymphocytes. Thus, Au/CuNDs-R848 played a role as an "in situ nanovaccine" to enhance the immunogenicity of TNBC by inducing immunogenic cell death (ICD). On the other hand, the nanovaccine suppressed the myeloid-derived suppressor cells (MDSCs), thereby reversing the immunosuppressive microenvironment. Through the dual immunoregulation, "cold tumor" was transformed into a "hot tumor", not only implementing a "turning foes to friends" therapeutic strategy but also enhancing immunotherapy against metastatic TNBC. Furthermore, Au/CuNDs-R848 acted as an excellent nanoprobe, enabling high-resolution near-infrared fluorescence and computed tomography imaging for precise visualization of TNBC. This feature offers potential applications in clinical cancer detection and surgical guidance. Collectively, this work provides an effective strategy for enhancing immune response and offers novel insights into the potential clinical applications for tumor immunotherapy.

Shikonin and chitosan-silver nanoparticles synergize against triple-negative breast cancer through RIPK3-triggered necroptotic immunogenic cell death

Necroptotic immunogenic cell death (ICD) can activate the human immune system to treat the metastasis and recurrence of triple-negative breast cancer (TNBC). However, developing the necroptotic inducer and precisely delivering it to the tumor site is the key issue. Herein, we reported that the combination of shikonin (SHK) and chitosan silver nanoparticles (Chi-Ag NPs) effectively induced ICD by triggering necroptosis in 4T1 cells. Moreover, to address the lack of selectivity of drugs for in vivo application, we developed an MUC1 aptamer-targeted nanocomplex (MUC1@Chi-Ag@CPB@SHK, abbreviated as MUC1@ACS) for co-delivering SHK and Chi-Ag NPs. The accumulation of MUC1@ACS NPs at the tumor site showed a 6.02-fold increase compared to the free drug. Subsequently, upon reaching the tumor site, the acid-responsive release of SHK and Chi-Ag NPs from MUC1@ACS NPs cooperatively induced necroptosis in tumor cells by upregulating the expression of RIPK3, p-RIPK3, and tetrameric MLKL, thereby effectively triggering ICD. The sequential maturation of dendritic cells (DCs) subsequently enhanced the infiltration of CD8+ and CD4+ T cells in tumors, while inhibiting regulatory T cells (Treg cells), resulting in the effective treatment of primary and distal tumor growth and the inhibition of TNBC metastasis. This work highlights the importance of nanoparticles in mediating drug interactions during necroptotic ICD.

Enhanced catalytic activity of Fe3O4-carbon dots complex in the Fenton reaction for enhanced immunotherapeutic and oxygenation effects

Tumor metastasis and recurrence are closely related to immune escape and hypoxia. Chemodynamic therapy (CDT), photodynamic therapy (PDT), and photothermal therapy (PTT) can induce immunogenic cell death (ICD), and their combination with immune checkpoint agents is a promising therapeutic strategy. Iron based nanomaterials have received more and more attention, but their low Fenton reaction efficiency has hindered their clinical application. In this study, Fe3O4-carbon dots complex (Fe3O4-CDs) was synthesized, which was modified with ferrocenedicarboxylic acid by amide bond, and crosslinked into Fe3O4-CDs@Fc nano complex. The CDs catalyzed the Fenton reaction activity of Fe3O4 by helping to improve the electron transfer efficiency, extended the reaction pH condition to 7.4. The Fe3O4-CDs@Fc exhibit exceptional optical activity, achieving a thermal conversion efficiency of 56.43 % under 808 nm light and a photosensitive single-line state oxygen quantum yield of 33 % under 660 nm light. Fe3O4-CDs@Fc improved intracellular oxygen level and inhibited hypoxia-inducing factor (HIF-1α) by in-situ oxygen production based on Fenton reaction. The multimodal combination of Fe3O4-CDs@Fc (CDT/PDT/PTT) strongly induced immune cell death (ICD). The expression of immune-related protein and HIF-1α was investigated by immunofluorescence method. In vivo, Fe3O4-CDs@Fc combined with immune checkpoint blocker (antibody PD-L1, αPD-L1) effectively ablated primary tumors and inhibited distal tumor growth. Fe3O4-CDs@Fc is a promising immune-antitumor drug.

Applications of nanotechnology in remodeling the tumour microenvironment for glioblastoma treatment

With the increasing research and deepening understanding of the glioblastoma (GBM) tumour microenvironment (TME), novel and more effective therapeutic strategies have been proposed. The GBM TME involves intricate interactions between tumour and non-tumour cells, promoting tumour progression. Key therapeutic goals for GBM treatment include improving the immunosuppressive microenvironment, enhancing the cytotoxicity of immune cells against tumours, and inhibiting tumour growth and proliferation. Consequently, remodeling the GBM TME using nanotechnology has emerged as a promising approach. Nanoparticle-based drug delivery enables targeted delivery, thereby improving treatment specificity, facilitating combination therapies, and optimizing drug metabolism. This review provides an overview of the GBM TME and discusses the methods of remodeling the GBM TME using nanotechnology. Specifically, it explores the application of nanotechnology in ameliorating immune cell immunosuppression, inducing immunogenic cell death, stimulating, and recruiting immune cells, regulating tumour metabolism, and modulating the crosstalk between tumours and other cells.

A RIPK1-specific PROTAC degrader achieves potent antitumor activity by enhancing immunogenic cell death

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a critical stress sentinel that coordinates cell survival, inflammation, and immunogenic cell death (ICD). Although the catalytic function of RIPK1 is required to trigger cell death, its non-catalytic scaffold function mediates strong pro-survival signaling. Accordingly, cancer cells can hijack RIPK1 to block necroptosis and evade immune detection. We generated a small-molecule proteolysis-targeting chimera (PROTAC) that selectively degraded human and murine RIPK1. PROTAC-mediated depletion of RIPK1 deregulated TNFR1 and TLR3/4 signaling hubs, accentuating the output of NF-κB, MAPK, and IFN signaling. Additionally, RIPK1 degradation simultaneously promoted RIPK3 activation and necroptosis induction. We further demonstrated that RIPK1 degradation enhanced the immunostimulatory effects of radio- and immunotherapy by sensitizing cancer cells to treatment-induced TNF and interferons. This promoted ICD, antitumor immunity, and durable treatment responses. Consequently, targeting RIPK1 by PROTACs emerges as a promising approach to overcome radio- or immunotherapy resistance and enhance anticancer therapies.

Autophagy-Inducing MoO3-x Nanowires Boost Photothermal-Triggered Cancer Immunotherapy

Autophagy could play suppressing role in cancer therapy by facilitating release of tumor antigens from dying cells and inducing immunogenic cell death (ICD). Therefore, discovery and rational design of more effective inducers of cytotoxic autophagy is expected to develop new strategies for finding innovative drugs for precise and successful cancer treatment. Herein, we develop MoO3-x nanowires (MoO3-x NWs) with high oxygen vacancy and strong photothermal responsivity to ablate tumors through hyperthermia, thus promote the induction of cytotoxic autophagy and severe ICD. As expected, the combination of MoO3-x NWs and photothermal therapy (PTT) effectively induces autophagy to promote the release of tumor antigens from the ablated cells, and induces the maturation and antigen presentation of dendritic cells (DCs), subsequently activates cytotoxic T lymphocytes (CTLs)-mediated adaptive immunity. Furthermore, the combination treatment of MoO3-x NWs with immune checkpoint blockade of PD-1 could promote the tumor-associated macrophages (TAMs) polarization into tumor-killing M1 macrophages, inhibit infiltration of Treg cells at tumor sites, and alleviate immunosuppression in the tumor microenvironment, finally intensify the anti-tumor activity in vivo. This study provides a strategy and preliminary elucidation of the mechanism of using MoO3-x nanowires with high oxygen vacancy to induce autophagy and thus enhance photothermal immunotherapy.

Metformin induces tumor immunogenic cell death in ovarian cancer by activating AMPK pathway

Inducing immunogenic cell death (ICD) process may be an important antitumor strategy in ovarian cancer (OC). Metformin (Met) has been shown to have antitumor effects in OC, but whether it mediates the ICD to inhibit OC process is unclear. Human OC cell lines (SKOV3 and A2780) were treated with Met. Dendritic cell (DC) and CD8+T cells were isolated from the peripheral blood mononuclear cells of volunteers. Cell counting kit 8 assay was used to measure cell viability, and immunofluorescence staining was performed to detect the percentages of membrane and intracellular calreticulin (CRT). CRT level, DC maturation and effector cell activation were evaluated by flow cytometry. The levels of IL-10 and IFN-γ, as well as the releasements of HMGB1 and ATP, were detected using corresponding kits. The protein levels of heat shock protein 70/90 (HSP70/90) and AMPKα were tested by western blot analysis, and the mRNA levels of CD80, CD86, IL-10, and IFN-γ were measured by quantitative real-time PCR. Colony formation assay was utilized for assessing cell cytotoxicity. Mice transplanted tumor model was constructed to assess the effect of Met on OC tumor growth, and immunohistochemistry staining was used to analyze CD80+ and CD86+ cells in mice tumor tissues. Our data showed that Met inhibited OC cell viability and induced CRT exposure. Besides, Met could promote the release of HMGB1 and ATP, as well as induce DC maturation. In vivo experiments suggested that Met restrained OC tumor growth via activating antitumor immune response. Moreover, Met activated AMPK pathway, and silenced AMPK pathway reversed the promoting effect of Met on CRT exposure and the releasements of HMGB1 and ATP in OC cells. In conclusion, Met induced ICD-mediated immune destruction in OC via activating AMPK pathway, indicating that Met might be used in the immunotherapy of OC.

A new MVA ancestor-derived oncolytic vaccinia virus induces immunogenic tumor cell death and robust antitumor immune responses

Vaccinia viruses (VACVs) are versatile therapeutic agents and different features of various VACV strains allow for a broad range of therapeutic applications. Modified VACV Ankara (MVA) is a particularly altered VACV strain that is highly immunogenic, incapable of replicating in mammalian hosts, and broadly used as a safe vector for vaccination. Alternatively, Western Reserve (WR) or Copenhagen (Cop) are VACV strains that efficiently replicate in cancer cells and, therefore, are used to develop oncolytic viruses. However, the immune evasion capacity of WR or Cop hinders their ability to elicit antitumor immune responses, which is crucial for efficacy in the clinic. Here, we describe a new VACV strain named Immune-Oncolytic VACV Ankara (IOVA), which combines efficient replication in cancer cells with induction of immunogenic tumor cell death (ICD). IOVA was engineered from an MVA ancestor and shows superior cytotoxicity in tumor cells. In addition, the IOVA genome incorporates mutations that lead to massive fusogenesis of tumor cells, which contributes to improved antitumor effects. In syngeneic mouse tumor models, the induction of ICD results in robust antitumor immunity directed against tumor neo-epitopes and eradication of large established tumors. These data present IOVA as an improved immunotherapeutic oncolytic vector.

Multifunctional hydrogels based on photothermal therapy: A prospective platform for the postoperative management of melanoma

Preventing the recurrence of melanoma after surgery and accelerating wound healing are among the most challenging aspects of melanoma management. Photothermal therapy has been widely used to treat tumors and bacterial infections and promote wound healing. Owing to its efficacy and specificity, it may be used for postoperative management of tumors. However, its use is limited by the uncontrollable distribution of photosensitizers and the likelihood of damage to the surrounding normal tissue. Hydrogels provide a moist environment with strong biocompatibility and adhesion for wound healing owing to their highly hydrophilic three-dimensional network structure. In addition, these materials serve as excellent drug carriers for tumor treatment and wound healing. It is possible to combine the advantages of both of these agents through different loading modalities to provide a powerful platform for the prevention of tumor recurrence and wound healing. This review summarizes the design strategies, research progress and mechanism of action of hydrogels used in photothermal therapy and discusses their role in preventing tumor recurrence and accelerating wound healing. These findings provide valuable insights into the postoperative management of melanoma and may guide the development of promising multifunctional hydrogels for photothermal therapy.

Molecular subtype identification and prognosis stratification by a immunogenic cell death-related gene expression signature in colorectal cancer

OBJECTIVES

This study intended to develop a new immunogenic cell death (ICD)-related prognostic signature for colorectal cancer (CRC) patients.

RESEARCH DESIGN AND METHODS

The Non-Negative Matrix Factorization (NMF) algorithm was adopted to cluster tumor samples based on ICD gene expression to obtain ICD-related subtypes. Survival analysis and immune microenvironment analysis were conducted among different subtypes. Regression analysis was used to construct the model. Based on riskscore median, cancer patients were classified into high and low risk groups, and independent prognostic ability of the model was analyzed. The CIBERSORT algorithm was adopted to determine the immune infiltration level of both groups.

RESULTS

We analyzed the differential genes between cluster 4 and cluster 1-3 and obtained 12 genes with the best prognostic features finally (NLGN1, SLC30A3, C3orf20, ADAD2, ATOH1, ATP6V1B1, KCNQ2, MUCL3, RGCC, CLEC17A, COL6A5, and INSL4). In addition, patients with lower risk had higher levels of infiltration of most immune cells, lower Tumor Immune Dysfunction and Exclusion (TIDE) level and higher immunophenscore (IPS) level than those with higher risk.

CONCLUSIONS

This study constructed and validated the ICD feature signature predicting CRC prognosis and provide a reference criteria for guiding the prognosis and immunotherapy of CRC cancer patients.

PLD1 is a key player in cancer stemness and chemoresistance: Therapeutic targeting of cross-talk between the PI3K/Akt and Wnt/β-catenin pathways

The development of chemoresistance is a major challenge in the treatment of several types of cancers in clinical settings. Stemness and chemoresistance are the chief causes of poor clinical outcomes. In this context, we hypothesized that understanding the signaling pathways responsible for chemoresistance in cancers is crucial for the development of novel targeted therapies to overcome drug resistance. Among the aberrantly activated pathways, the PI3K-Akt/Wnt/β-catenin signaling pathway is clinically implicated in malignancies such as colorectal cancer (CRC) and glioblastoma multiforme (GBM). Aberrant dysregulation of phospholipase D (PLD) has been implicated in several malignancies, and oncogenic activation of this pathway facilitates tumor proliferation, stemness, and chemoresistance. Crosstalk involving the PLD and Wnt/β-catenin pathways promotes the progression of CRC and GBM and reduces the sensitivity of cancer cells to standard therapies. Notably, both pathways are tightly regulated and connected at multiple levels by upstream and downstream effectors. Thus, gaining deeper insights into the interactions between these pathways would help researchers discover unique therapeutic targets for the management of drug-resistant cancers. Here, we review the molecular mechanisms by which PLD signaling stimulates stemness and chemoresistance in CRC and GBM. Thus, the current review aims to address the importance of PLD as a central player coordinating cross-talk between the PI3K/Akt and Wnt/β-catenin pathways and proposes the possibility of targeting these pathways to improve cancer therapy and overcome drug resistance.

Identification of pancreatic adenocarcinoma immune subtype associated with tumor neoantigen from aberrant alternative splicing

Background

Pancreatic adenocarcinoma (PAAD) is referred to as an immunologically "cold" tumor that responds poorly to immunotherapy. A fundamental theory that explains the low immunogenicity of PAAD is the dramatically low tumor mutation burden (TMB) of PAAD tumors, which fails to induce sufficient immune response. Alternative splicing of pre-mRNA, which could alter the proteomic diversity of many cancers, has been reported to be involved in neoantigen production. Therefore, we aim to identify novel PAAD antigens and immune subtypes through systematic bioinformatics research.

Methods

Data for splicing analysis were downloaded from The Cancer Genome Atlas (TCGA) SpliceSeq database. Among the available algorithms, we chose CIBERSORT to evaluate the immune cell distribution among PAADs. The TCGA-PAAD expression matrix was used to construct a co-expression network. Single-cell analysis was performed based on the Seurat workflow.

Results

Integrated analysis of aberrantly upregulated genes, alternatively spliced genes, genes associated with nonsense-mediated RNA decay (NMD) factors, antigen presentation and overall survival (OS) in TCGA-PAAD revealed that PLEC is a promising neoantigen for PAAD-targeted therapy. We identified a C2 TCGA-PAAD subtype that had better prognosis and more CD8+ T-cell infiltration. We propose a novel immune subtyping system for PAAD to indicate patient prognosis and opportunities for immunotherapy, such as immune checkpoint (ICP) inhibitors.

Conclusions

In conclusion, the present study used a transcriptome-guided approach to screen neoantigen candidates based on alternative splicing, NMD factors, and antigen-presenting signatures for PAAD. A prognosis model with guidance of immunotherapy will aid in patient selection for appropriate treatment.

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.

Recent advances in biomimetic strategies for the immunotherapy of glioblastoma

Immunotherapy is regarded as one of the most promising approaches for treating tumors, with a multitude of immunotherapeutic thoughts currently under consideration for the lethal glioblastoma (GBM). However, issues with immunotherapeutic agents, such as limited in vivo stability, poor blood-brain barrier (BBB) penetration, insufficient GBM targeting, and represented monotherapy, have hindered the success of immunotherapeutic interventions. Moreover, even with the aid of conventional drug delivery systems, outcomes remain suboptimal. Biomimetic strategies seek to overcome these formidable drug delivery challenges by emulating nature's intelligent structures and functions. Leveraging the variety of biological structures and functions, biomimetic drug delivery systems afford a versatile platform with enhanced biocompatibility for the co-delivery of diverse immunotherapeutic agents. Moreover, their inherent capacity to traverse the BBB and home in on GBM holds promise for augmenting the efficacy of GBM immunotherapy. Thus, this review begins by revisiting the various thoughts and agents on immunotherapy for GBM. Then, the barriers to successful GBM immunotherapy are analyzed, and the corresponding biomimetic strategies are explored from the perspective of function and structure. Finally, the clinical translation's current state and prospects of biomimetic strategy are addressed. This review aspires to provide fresh perspectives on the advancement of immunotherapy for GBM.

Characterizing the immune tumor microenvironment in ALK fusion-positive lung cancer: state-of-the-art and therapeutical implications

INTRODUCTION

Approximately 5% of non-small cell lung cancer (NSCLC), exhibits anaplastic lymphoma kinase (ALK) rearrangements. EML4-ALK fusions account for over 90% of ALK rearrangements in NSCLC. The advent of treatment targeting ALK has significantly improved survival rates in patients with advanced ALK-positive NSCLC. However, the emergence of resistance mechanisms and the subsequent progression disease inevitably occurs. The tumor immune microenvironment (TIME) plays a pivotal role in lung cancer, influencing disease development, patient's outcomes, and response to treatments.

AREAS COVERED

The aim of this review is to provide a comprehensive characterization of the TIME in ALK rearranged NSCLC and its intrinsic plasticity under treatment pressure.

EXPERT OPINION

Recognizing the fundamental role of the TIME in cancer progression has shifted the paradigm from a tumor cell-centric perspective to the understanding of a complex tumor ecosystem. Understanding the intricate dynamics of the TIME, its influence on treatment response, and the potential of immunotherapy in patients with ALK-positive NSCLC are currently among the primary research objectives in this patient population.

Phase and Defect Engineering of MoSe2 Nanosheets for Enhanced NIR-II Photothermal Immunotherapy

Inducing immunogenic cell death (ICD) during photothermal therapy (PTT) has the potential to effectively trigger photothermal immunotherapy (PTI). However, ICD induced by PTT alone is often limited by inefficient PTT, low immunogenicity of tumor cells, and a dysregulated redox microenvironment. Herein, we develop MoSe2 nanosheets with high-percentage metallic 1T phase and rich exposed active Mo centers through phase and defect engineering of MoSe2 as an effective nanoagent for PTI. The metallic 1T phase in MoSe2 nanosheets endows them with strong PTT performance, and the abundant exposed active Mo centers endow them with high activity for glutathione (GSH) depletion. The MoSe2-mediated high-performance PTT synergizing with efficient GSH depletion facilitates the release of tumor-associated antigens to induce robust ICD, thus significantly enhancing checkpoint blockade immunotherapy and activating systemic immune response in mouse models of colorectal cancer and triple-negative metastatic breast cancer.

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.

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.

"Find Me" and "Eat Me" signals: tools to drive phagocytic processes for modulating antitumor immunity

Phagocytosis, a vital defense mechanism, involves the recognition and elimination of foreign substances by cells. Phagocytes, such as neutrophils and macrophages, rapidly respond to invaders; macrophages are especially important in later stages of the immune response. They detect "find me" signals to locate apoptotic cells and migrate toward them. Apoptotic cells then send "eat me" signals that are recognized by phagocytes via specific receptors. "Find me" and "eat me" signals can be strategically harnessed to modulate antitumor immunity in support of cancer therapy. These signals, such as calreticulin and phosphatidylserine, mediate potent pro-phagocytic effects, thereby promoting the engulfment of dying cells or their remnants by macrophages, neutrophils, and dendritic cells and inducing tumor cell death. This review summarizes the phagocytic "find me" and "eat me" signals, including their concepts, signaling mechanisms, involved ligands, and functions. Furthermore, we delineate the relationships between "find me" and "eat me" signaling molecules and tumors, especially the roles of these molecules in tumor initiation, progression, diagnosis, and patient prognosis. The interplay of these signals with tumor biology is elucidated, and specific approaches to modulate "find me" and "eat me" signals and enhance antitumor immunity are explored. Additionally, novel therapeutic strategies that combine "find me" and "eat me" signals to better bridge innate and adaptive immunity in the treatment of cancer patients are discussed.

A Carbon-Caged Rhodamine Generating Nitrosoperoxycarbonate for Photoimmunotherapy

Photoimmunotherapy is a promising cancer treatment modality. While potent 1-e- oxidative species are known to induce immunogenic cell death (ICD), they are also associated with unspecific oxidation and collateral tissue damage. This difficulty may be addressed by post-generation radical reinforcement. Namely, non-oxidative radicals are first generated and subsequently activated into powerful oxidative radicals to induce ICD. Here, we developed a photo-triggered molecular donor (NPCD565) of nitrosoperoxycarbonate (ONOOCO2 -), the first of its class to our knowledge, and further evaluated its feasibility for immunotherapy. Upon irradiation of NPCD565 by light within a broad spectral region from ultraviolet to red, ONOOCO2 - is released along with a bright rhodamine dye (RD565), whose fluorescence is a reliable and convenient build-in reporter for the localization, kinetics, and dose of ONOOCO2 - generation. Upon photolysis of NPCD565 in 4T1 cells, damage-associated molecular patterns (DAMPs) indicative of ICD were observed and confirmed to exhibit immunogenicity by induced maturation of dendritic cells. In vivo studies with a bilateral tumor-bearing mouse model showcased the potent tumor-killing capability of NPCD565 of the primary tumors and growth suppression of the distant tumors. This work unveils the potent immunogenicity of ONOOCO2 -, and its donor (NPCD565) has broad potential for photo-immunotherapy of cancer.

Polymersomal Poly(I:C) Self-Magnifies Antitumor Immunity by Inducing Immunogenic Cell Death and Systemic Immune Activation

Immunotherapy has emerged as a powerful weapon against lung cancer, yet only a fraction of patients respond to the treatment. Poly(I:C) (PIC) effectively triggers both innate and adaptive immunity. It can also induce immunogenic cell death (ICD) in tumor cells. However, its efficacy is hindered by its instability in vivo and limited cellular uptake. To address this, PIC is encapsulated in cRGD-functionalized polymersomes (t-PPIC), which significantly increases its stability and uptake, thus activating dendritic cells (DCs) and inducing apoptosis of lung tumor cells in vitro. In a murine LLC lung tumor model, systemic administration of t-PPIC effectively suppresses tumor growth and leads to survival benefits, with 40% of the mice becoming tumor-free. Notably, t-PPIC provokes stronger apoptosis and ICD in tumor tissue and elicits a more potent stimulation of DCs, recruitment of natural killer (NK) cells, and activation of CD8+ T cells, compared to free PIC and nontargeted PPIC controls. Furthermore, when combined with immune checkpoint inhibitors or radiotherapy, t-PPIC amplifies the antitumor immune response, resulting in complete regression in 60% of the mice. These compelling findings underscore the potential of integrin-targeted polymersomal PIC to enhance antitumor immunity by simultaneously inducing ICD and systemic immune activation.

4-Deoxy-ε-Pyrromycinone: A Promising Drug/Lead Compound to Treat Tumors

Background

Anthraquinone drugs are widely used in the treatment of tumors. However, multidrug resistance and severe cardiac toxicity limit its use, which have led to the discovery of new analogues. In this paper, 4-Deoxy-ε-pyrromycinone (4-Deo), belonging to anthraquinone compounds, was first been studied with the anti-tumor effects and the safety in vitro and in vivo as a new anti-tumor drug or lead compound.

Methods

The quantitative analysis of 4-Deo was established by UV methodology. The anti-cancer effect of 4-Deo in vitro was evaluated by cytotoxicity experiments of H22, HepG2 and Caco2, and the anti-cancer mechanism was explored by cell apoptosis and cycle. The tumor-bearing mouse model was established by subcutaneous inoculation of H22 cells to evaluate the anti-tumor effect of 4-Deo in vivo. The safety of 4-Deo was verified by the in vitro safety experiments of healthy cells and the in vivo safety experiments of H22 tumor-bearing mice. Tumor tissue sections were labeled with CRT, HMGB1, IL-6 and CD115 to explore the preliminary anti-cancer mechanism by immunohistochemistry.

Results

In vitro experiments demonstrated that 4-Deo could inhibit the growth of H22 by inducing cell necrosis and blocking cells in S phase, and 4-Deo has less damage to healthy cells. In vivo experiments showed that 4-Deo increased the positive area of CRT and HMGB1, which may inhibit tumor growth by triggering immunogenic cell death (ICD). In addition, 4-Deo reduced the positive area of CSF1R, and the anti-tumor effect may be achieved by blocking the transformation of tumor-associated macrophages (TAMs) to M2 phenotype.

Conclusion

In summary, this paper demonstrated the promise of 4-Deo for cancer treatment in vitro and in vivo. This paper lays the foundation for the study of 4-Deo, which is beneficial for the further development anti-tumor drugs based on the lead compound of 4-Deo.

Hyperbaric oxygen enhances tumor penetration and accumulation of engineered bacteria for synergistic photothermal immunotherapy

Bacteria-mediated cancer therapeutic strategies have attracted increasing interest due to their intrinsic tumor tropism. However, bacteria-based drugs face several challenges including the large size of bacteria and dense extracellular matrix, limiting their intratumoral delivery efficiency. In this study, we find that hyperbaric oxygen (HBO), a noninvasive therapeutic method, can effectively deplete the dense extracellular matrix and thus enhance the bacterial accumulation within tumors. Inspired by this finding, we modify Escherichia coli Nissle 1917 (EcN) with cypate molecules to yield EcN-cypate for photothermal therapy, which can subsequently induce immunogenic cell death (ICD). Importantly, HBO treatment significantly increases the intratumoral accumulation of EcN-cypate and facilitates the intratumoral infiltration of immune cells to realize desirable tumor eradication through photothermal therapy and ICD-induced immunotherapy. Our work provides a facile and noninvasive strategy to enhance the intratumoral delivery efficiency of natural/engineered bacteria, and may promote the clinical translation of bacteria-mediated synergistic cancer therapy.

Environment-responsive dendrobium polysaccharide hydrogel embedding manganese microsphere as a post-operative adjuvant to boost cascaded immune cycle against melanoma

Rationale: Surgical resection is a primary treatment for solid tumors, but high rates of tumor recurrence and metastasis post-surgery present significant challenges. Manganese (Mn2+), known to enhance dendritic cell-mediated cancer immunotherapy by activating the cGAS-STING pathway, has potential in post-operative cancer management. However, achieving prolonged and localized delivery of Mn2+ to stimulate immune responses without systemic toxicity remains a challenge. Methods: We developed a post-operative microenvironment-responsive dendrobium polysaccharide hydrogel embedded with Mn2+-pectin microspheres (MnP@DOP-Gel). This hydrogel system releases Mn2+-pectin microspheres (MnP) in response to ROS, and MnP shows a dual effect in vitro: promoting immunogenic cell death and activating immune cells (dendritic cells and macrophages). The efficacy of MnP@DOP-Gel as a post-surgical treatment and its potential for immune activation were assessed in both subcutaneous and metastatic melanoma models in mice, exploring its synergistic effect with anti-PD1 antibody. Result: MnP@DOP-Gel exhibited ROS-responsive release of MnP, which could exert dual effects by inducing immunogenic cell death of tumor cells and activating dendritic cells and macrophages to initiate a cascade of anti-tumor immune responses. In vivo experiments showed that the implanted MnP@DOP-Gel significantly inhibited residual tumor growth and metastasis. Moreover, the combination of MnP@DOP-Gel and anti-PD1 antibody displayed superior therapeutic potency in preventing either metastasis or abscopal brain tumor growth. Conclusions: MnP@DOP-Gel represents a promising drug-free strategy for cancer post-operative management. Utilizing this Mn2+-embedding and ROS-responsive delivery system, it regulates surgery-induced immune responses and promotes sustained anti-tumor responses, potentially increasing the effectiveness of surgical cancer treatments.

Sensitize Tumor Immunotherapy: Immunogenic Cell Death Inducing Nanosystems

Low immunogenicity of tumors poses a challenge in the development of effective tumor immunotherapy. However, emerging evidence suggests that certain therapeutic approaches, such as chemotherapy, radiotherapy, and phototherapy, can induce varying degrees of immunogenic cell death (ICD). This ICD phenomenon leads to the release of tumor antigens and the maturation of dendritic cells (DCs), thereby enhancing tumor immunogenicity and promoting immune responses. However, the use of a single conventional ICD inducer often fails to achieve in situ tumor ablation and establish long-term anti-tumor immune responses. Furthermore, the induction of ICD induction varies among different approaches, and the distribution of the therapeutic agent within the body influences the level of ICD and the occurrence of toxic side effects. To address these challenges and further boost tumor immunity, researchers have explored nanosystems as inducers of ICD in combination with tumor immunotherapy. This review examines the mechanisms of ICD and different induction methods, with a specific focus on the relationship between ICD and tumor immunity. The aim is to explore the research advancements utilizing various nanomaterials to enhance the body's anti-tumor effects by inducing ICD. This paper aims to contribute to the development and clinical application of nanomaterial-based ICD inducers in the field of cancer immunotherapy by providing important theoretical guidance and practical references.

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.

Beyond Anti-PD-1/PD-L1: Improving Immune Checkpoint Inhibitor Responses in Triple-Negative Breast Cancer

The introduction of anti-programmed cell death protein-1 (anti-PD-1) to the clinical management of triple-negative breast cancer (TNBC) represents a breakthrough for a disease whose treatment has long relied on the standards of chemotherapy and surgery. Nevertheless, few TNBC patients achieve a durable remission in response to anti-PD-1, and there is a need to develop strategies to maximize the potential benefit of immune checkpoint inhibition (ICI) for TNBC patients. In the present review, we discuss three conceptual strategies to improve ICI response rates in TNBC patients. The first effort involves improving patient selection. We discuss proposed biomarkers of response and resistance to anti-PD-1, concluding that an optimal biomarker will likely be multifaceted. The second effort involves identifying existing targeted therapies or chemotherapies that may synergize with ICI. In particular, we describe recent efforts to use inhibitors of the PI3K/AKT or RAS/MAPK/ERK pathways in combination with ICI. Third, considering the possibility that targeting the PD-1 axis is not the most promising strategy for TNBC treatment, we describe ongoing efforts to identify novel immunotherapy strategies.

ROS-responsive thermosensitive polypeptide hydrogels for localized drug delivery and improved tumor chemoimmunotherapy

In this study, we developed a ROS-responsive thermosensitive poly(ethylene glycol)-polypeptide hydrogel loaded with a chemotherapeutic drug, doxorubicin (Dox), an antiviral imidazoquinoline, resiquimod (R848), and antibody targeting programmed cell death protein 1 (aPD-1) for local chemoimmunotherapy. The hydrogel demonstrated controllable degradation and sustained drug release behavior according to the concentration of ROS in vitro. Following intratumoral injection into mice bearing B16F10 melanoma, the Dox/R848/aPD-1 co-loaded hydrogel effectively inhibited tumor growth, prolonged animal survival time and promoted anti-tumor immune responses with low systemic toxicity. In the postoperative model, the Dox/R848/aPD-1 co-loaded hydrogel exhibited enhanced tumor recurrence prevention and long-term immune memory effects. Thus, the hydrogel-based local chemoimmunotherapy system demonstrates potential for effective anti-tumor treatment and suppression of tumor recurrence.

An immunogenic cell death-related lncRNA signature correlates with prognosis and tumor immune microenvironment in bladder cancer

Immunogenic cell death (ICD) is a newly discovered form of cellular demise that triggers adaptive immune responses mediated by T cells. However, the immunogenic cell death-related lncRNAs (ICDRLs) involved in bladder cancer (BC) development and progression remain to be further elucidated. Molecular profiling data and clinicopathological information for BC patients were obtained from TCGA, and the ICDRGs list was obtained from published literature. For the identification of ICDRLs, Pearson co-expression analysis was performed, and a prognostic signature based on 13 ICDRLs was constructed by univariate assays and LASSO assays. Herein, an ICDRLSig consisting of 13 ICDRLs was constructed. KM curves and ROC curves demonstrated that the constructed signature in the TCGA training, testing, entire and external sets have good predictive performance. Multivariate assays illuminated that the signature is an independent predictor for BC patients' OS, exhibiting greater predictive power for the survival than traditional clinicopathological features. Additionally, patients in the high-ICDRLSig risk subgroup had more abundant immune infiltration, higher immune checkpoint gene expression, lower TMB and poorer response to immunotherapy. We have developed a novel ICDRLSig that can be exploited for survival prediction and provide a reference for further individualized treatment.

Boosting Checkpoint Immunotherapy with Biomimetic Nanodrug Delivery Systems

Immune checkpoint blockade (ICB) has achieved unprecedented progress in tumor immunotherapy by blocking specific immune checkpoint molecules. However, the high biodistribution of the drug prevents it from specifically targeting tumor tissues, leading to immune-related adverse events. Biomimetic nanodrug delivery systems (BNDSs) readily applicable to ICB therapy have been widely developed at the preclinical stage to avoid immune-related adverse events. By exploiting or mimicking complex biological structures, the constructed BNDS as a novel drug delivery system has good biocompatibility and certain tumor-targeting properties. Herein, the latest findings regarding the aforementioned therapies associated with ICB therapy are highlighted. Simultaneously, prospective bioinspired engineering strategies can be designed to overcome the four-level barriers to drug entry into lesion sites. In future clinical translation, BNDS-based ICB combination therapy represents a promising avenue for cancer treatment.

Immune landscape and response to oncolytic virus-based immunotherapy

Oncolytic virus (OV)-based immunotherapy has emerged as a promising strategy for cancer treatment, offering a unique potential to selectively target malignant cells while sparing normal tissues. However, the immunosuppressive nature of tumor microenvironment (TME) poses a substantial hurdle to the development of OVs as effective immunotherapeutic agents, as it restricts the activation and recruitment of immune cells. This review elucidates the potential of OV-based immunotherapy in modulating the immune landscape within the TME to overcome immune resistance and enhance antitumor immune responses. We examine the role of OVs in targeting specific immune cell populations, including dendritic cells, T cells, natural killer cells, and macrophages, and their ability to alter the TME by inhibiting angiogenesis and reducing tumor fibrosis. Additionally, we explore strategies to optimize OV-based drug delivery and improve the efficiency of OV-mediated immunotherapy. In conclusion, this review offers a concise and comprehensive synopsis of the current status and future prospects of OV-based immunotherapy, underscoring its remarkable potential as an effective immunotherapeutic agent for cancer treatment.

Cell Membrane-Targeting Type I/II Photodynamic Therapy Combination with FSP1 Inhibition for Ferroptosis-Enhanced Photodynamic Immunotherapy

An imbalance in reactive oxygen species (ROS) levels in tumor cells can result in the accumulation of lipid peroxide (LPO) which can induce ferroptosis. Moreover, elevated ROS levels in tumors present a chance to develop ROS-based cancer therapeutics including photodynamic therapy (PDT) and ferroptosis. However, their anticancer efficacies are compromised by insufficient oxygen levels and inherent cellular ROS regulatory mechanism. Herein, a cell membrane-targeting photosensitizer, TBzT-CNQi, which can generate 1O2, •OH, and O2 •- via type I/II process to induce a high level of LPO for potent ferroptosis and photodynamic therapy is developed. The FSP1 inhibitor (iFSP1) is incorporated with TBzT-CNQi to downregulate FSP1 expression, lower the intracellular CoQ10 content, induce a high level of LPO, and activate initial tumor immunogenic ferroptosis. In vitro and in vivo experiments demonstrate that the cell membrane-targeting type I/II PDT combination with FSP1 inhibition can evoke strong ICD and activate the immune response, which subsequently promotes the invasion of CD8+ T cells infiltration, facilitates the dendritic cell maturation, and decreases the tumor infiltration of tumor-associated macrophages. The study indicates that the combination of cell membrane-targeting type I/II PDT and FSP1 inhibition holds promise as a potential strategy for ferroptosis-enhanced photodynamic immunotherapy of hypoxia tumors.

Definitive chemoradiotherapy induces T-cell-inflamed tumor microenvironment in unresectable locally advanced esophageal squamous cell carcinoma

BACKGROUND

Chemoradiotherapy (CRT) modulates the tumor immune microenvironment of multiple cancer types, including esophageal cancer, which potentially induces both immunogenicity and immunosuppression by upregulating the presentation of tumor-specific antigens and immune checkpoint molecules in tumors, respectively. The prognostic effects of immune modification by CRT in esophageal squamous cell carcinoma (ESCC) remain controversial because of the lack of detailed immunological analyses using paired clinical specimens before and after CRT. We aimed to clarify the immunological changes in the tumor microenvironment caused by CRT and elucidate the predictive importance of clinical response and prognosis and the rationale for the necessity of subsequent programmed cell death protein 1 (PD-1) inhibitor treatment.

METHODS

In this study, we performed a comprehensive immunological analysis of paired biopsy specimens using multiplex immunohistochemistry before and after CRT in patients with unresectable locally advanced ESCC.

RESULTS

CRT significantly increased the intra-tumoral infiltration and PD-1 expression of CD8+ T cells and conventional CD4+ T cells but decreased those of regulatory T cells and the accumulation of tumor-associated macrophages. Multivariate analysis of tumor-infiltrating T-cell phenotypes revealed that the density of PD-1+CD8+ T cells in the tumor after CRT could predict a confirmed complete response and favorable survival.

CONCLUSIONS

This study showed that CRT improved the immunological characteristics of unresectable locally advanced ESCC and identified the density of PD-1+CD8+ T cells as a predictive factor for prognosis. This finding supports the rationale for the necessity of subsequent PD-1 inhibitor treatment.

The war between the immune system and the tumor - using immune biomarkers as tracers

Nowadays, immunotherapy is one of the most promising anti-tumor therapeutic strategy. Specifically, immune-related targets can be used to predict the efficacy and side effects of immunotherapy and monitor the tumor immune response. In the past few decades, increasing numbers of novel immune biomarkers have been found to participate in certain links of the tumor immunity to contribute to the formation of immunosuppression and have entered clinical trials. Here, we systematically reviewed the oncogenesis and progression of cancer in the view of anti-tumor immunity, particularly in terms of tumor antigen expression (related to tumor immunogenicity) and tumor innate immunity to complement the cancer-immune cycle. From the perspective of integrated management of chronic cancer, we also appraised emerging factors affecting tumor immunity (including metabolic, microbial, and exercise-related markers). We finally summarized the clinical studies and applications based on immune biomarkers. Overall, immune biomarkers participate in promoting the development of more precise and individualized immunotherapy by predicting, monitoring, and regulating tumor immune response. Therefore, targeting immune biomarkers may lead to the development of innovative clinical applications.

ATP and Formyl Peptides Facilitate Chemoattractant Leukotriene-B4 Synthesis and Drive Calcium Fluxes, Which May Contribute to Neutrophil Swarming at Sites of Cell Damage and Pathogens Invasion

Here, we demonstrate that human neutrophil interaction with the bacterium Salmonella typhimurium fuels leukotriene B4 synthesis induced by the chemoattractant fMLP. In this work, we found that extracellular ATP (eATP), the amount of which increases sharply during tissue damage, can effectively regulate fMLP-induced leukotriene B4 synthesis. The vector of influence strongly depends on the particular stage of sequential stimulation of neutrophils by bacteria and on the stage at which fMLP purinergic signaling occurs. Activation of 5-lipoxygenase (5-LOX), key enzyme of leukotriene biosynthesis, depends on an increase in the cytosolic concentration of Ca2+. We demonstrate that eATP treatment prior to fMLP, by markedly reducing the amplitude of the fMLP-induced Ca2+ transient jump, inhibits leukotriene synthesis. At the same time, when added with or shortly after fMLP, eATP effectively potentiates arachidonic acid metabolism, including by Ca2+ fluxes stimulation. Flufenamic acid, glibenclamide, and calmodulin antagonist R24571, all of which block calcium signaling in different ways, all suppressed 5-LOX product synthesis in our experimental model, indicating the dominance of calcium-mediated mechanisms in eATP regulatory potential. Investigation into the adhesive properties of neutrophils revealed the formation of cell clusters when adding fMLP to neutrophils exposed to the bacterium Salmonella typhimurium. eATP added simultaneously with fMLP supported neutrophil polarization and clustering. A cell-derived chemoattractant such as leukotriene B4 plays a crucial role in the recruitment of additional neutrophils to the foci of tissue damage or pathogen invasion, and eATP, through the dynamics of changes in [Ca2+]i, plays an important decisive role in fMLP-induced leukotrienes synthesis during neutrophil interactions with the bacterium Salmonella typhimurium.

Zebularine potentiates anti-tumor immunity by inducing tumor immunogenicity and improving antigen processing through cGAS-STING pathway

DNA methylation is an important epigenetic mechanism involved in the anti-tumor immune response, and DNA methyltransferase inhibitors (DNMTi) have achieved impressive therapeutic outcomes in patients with certain cancer types. However, it is unclear how inhibition of DNA methylation bridges the innate and adaptive immune responses to inhibit tumor growth. Here, we report that DNMTi zebularine reconstructs tumor immunogenicity, in turn promote dendritic cell maturation, antigen-presenting cell activity, tumor cell phagocytosis by APCs, and efficient T cell priming. Further in vivo and in vitro analyses reveal that zebularine stimulates cGAS-STING-NF-κB/IFNβ signaling to enhance tumor cell immunogenicity and upregulate antigen processing and presentation machinery (AgPPM), which promotes effective CD4+ and CD8+ T cell-mediated killing of tumor cells. These findings support the use of combination regimens that include DNMTi and immunotherapy for cancer treatment.

Engineered Bacteriophage-Based In Situ Vaccine Remodels a Tumor Microenvironment and Elicits Potent Antitumor Immunity

In situ vaccines (ISVs) utilize the localized delivery of chemotherapeutic agents or radiotherapy to stimulate the release of endogenous antigens from tumors, thereby eliciting systemic and persistent immune activation. Recently, a bioinspired ISV strategy has attracted tremendous attention due to its features such as an immune adjuvant effect and genetic plasticity. M13 bacteriophages are natural nanomaterials with intrinsic immunogenicity, genetic flexibility, and cost-effectiveness for large-scale production, demonstrating the potential for application in cancer vaccines. In this study, we propose an ISV based on the engineered M13 bacteriophage targeting CD40 (M13CD40) for dendritic cell (DC)-targeted immune stimulation, named H-GM-M13CD40. We induce immunogenic cell death and release tumor antigens through local delivery of (S)-10-hydroxycamptothecin (HCPT), followed by intratumoral injection of granulocyte-macrophage colony stimulating factor (GM-CSF) and M13CD40 to enhance DC recruitment and activation. We demonstrate that this ISV strategy can result in significant accumulation and activation of DCs at the tumor site, reversing the immunosuppressive tumor microenvironment. In addition, H-GM-M13CD40 can synergize with the PD-1 blockade and induce abscopal effects in cold tumor models. Overall, our study verifies the immunogenicity of the engineered M13CD40 bacteriophage and provides a proof of concept that the engineered M13CD40 phage can function as an adjuvant for ISVs.

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.

Clinical application of immunogenic cell death inducers in cancer immunotherapy: turning cold tumors hot

Immunotherapy has emerged as a promising cancer treatment option in recent years. In immune "hot" tumors, characterized by abundant immune cell infiltration, immunotherapy can improve patients' prognosis by activating the function of immune cells. By contrast, immune "cold" tumors are often less sensitive to immunotherapy owing to low immunogenicity of tumor cells, an immune inhibitory tumor microenvironment, and a series of immune-escape mechanisms. Immunogenic cell death (ICD) is a promising cellular process to facilitate the transformation of immune "cold" tumors to immune "hot" tumors by eliciting innate and adaptive immune responses through the release of (or exposure to) damage-related molecular patterns. Accumulating evidence suggests that various traditional therapies can induce ICD, including chemotherapy, targeted therapy, radiotherapy, and photodynamic therapy. In this review, we summarize the biological mechanisms and hallmarks of ICD and introduce some newly discovered and technologically innovative inducers that activate the immune system at the molecular level. Furthermore, we also discuss the clinical applications of combing ICD inducers with cancer immunotherapy. This review will provide valuable insights into the future development of ICD-related combination therapeutics and potential management for "cold" tumors.

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.

A fully biodegradable spherical nucleic acid nanoplatform for self-codelivery of doxorubicin and miR122 for innate and adaptive immunity activation

Facile construction of a fully biodegradable spherical nucleic acid (SNA) nanoplatform is highly desirable for clinical translations but remains rarely explored. We developed herein the first polycarbonate-based biodegradable SNA nanoplatform for self-codelivery of a chemotherapeutic drug, doxorubicin (DOX), and a human liver-specific miR122 for synergistic chemo-gene therapy of hepatocellular carcinoma (HCC). Ring-opening polymerization (ROP) of a carbonate monomer leads to a well-defined polycarbonate backbone for subsequent DOX conjugation to the pendant side chains via acidic pH-cleavage Schiff base links and miR122 incorporation to the chain termini via click coupling, affording an amphiphilic polycarbonate-DOX-miR122 conjugate, PBis-Mpa30-DOX-miR122 that can self-assemble into stabilized SNA. Besides the desired biodegradability, another notable merit of this nanoplatform is the use of miR122 not only for gene therapy but also for enhanced innate immune response. Together with the ICD-triggering effect of DOX, PBis-Mpa30-DOX-miR122 SNA-mediated DOX and miR122 codelivery leads to synergistic immunogenicity enhancement, resulting in tumor growth inhibition value (TGI) of 98.1 % significantly higher than those of the groups treated with only drug or gene in a Hepa1-6-tumor-bearing mice model. Overall, this study develops a useful strategy toward biodegradable SNA construction, and presents a drug and gene-based self-codelivery SNA with synergistic immunogenicity enhancement for efficient HCC therapy. STATEMENT OF SIGNIFICANCE: Facile construction of a fully biodegradable SNA nanoplatform is useful for in vivo applications but remains relatively unexplored likely due to the synthetic challenge. We report herein construction of a polycarbonate-based SNA nanoplatform for co-delivering a chemotherapeutic drug, DOX, and a human liver-specific miR-122 for synergistic HCC treatment. In addition to the desired biodegradability properties, this SNA nanoplatform integrates DOX-triggered ICD and miR-122-enhanced innate immunity for simultaneously activating adaptive and innate immunities, which leads to potent antitumor efficiency with a TGI value of 98.1 % in a Hepa1-6-tumor-bearing mice model.

An overview of the regulatory role of annexin A1 in the tumor microenvironment and its prospective clinical application (Review)

Although annexin A1 (ANXA1), a 37 kDa phospholipid‑binding anti‑inflammatory protein expressed in various tissues and cell types, has been investigated extensively for its regulatory role in cancer biology, studies have mainly focused on its intracellular role. However, cancer cells and stromal cells expressing ANXA1 have the ability to transmit signals within the tumor microenvironment (TME) through autocrine, juxtacrine, or paracrine signaling. This bidirectional crosstalk between cancer cells and their environment is also crucial for cancer progression, contributing to uncontrolled tumor proliferation, invasion, metastasis and resistance to therapy. The present review explored the important role of ANXA1 in regulating the cell‑specific crosstalk between various compartments of the TME and analyzed the guiding significance of the crosstalk effects in promotion or suppressing cancer progression in the development of cancer treatments. The literature shows that ANXA1 is critical for the regulation of the TME, indicating that ANXA1 signaling between cancer cells and the TME is a potential therapeutic target for the development of novel therapeutic approaches for impeding cancer development.

Enhancing Tumor Immunotherapy by Multivalent Anti-PD-L1 Nanobody Assembled via Ferritin Nanocage

Increasing immunotherapy response rate and durability can lead to significant improvements in cancer care. To address this challenge, a novel multivalent immune checkpoint therapeutic platform is constructed through site-specific ligation of anti-PD-L1 nanobody (Nb) on ferritin (Ftn) nanocage. Nb-Ftn blocks PD-1/PD-L1 interaction and downregulates PD-L1 levels via endocytosis-induced degradation. In addition, the cage structure of Ftn allows encapsulation of indocyanine green (ICG), an FDA-approved dye. Photothermal treatment with Nb-Ftn@ICG induces immunogenic death of tumor cells, which improves systemic immune response via maturation of dendritic cells and enhanced infiltration of T cells. Moreover, Nb-Ftn encapsulation significantly enhances cellular uptake, tumor accumulation and retention of ICG. In vivo assays showed that this nanoplatform ablates the primary tumor, suppresses abscopal tumors and inhibits tumor metastasis, leading to a prolonged survival rate. This work presents a novel strategy for improving cancer immunotherapy using multivalent nanobody-ferritin conjugates as immunological targeting and enhancing carriers.

Reversing cancer immunoediting phases with a tumor-activated and optically reinforced immunoscaffold

In situ vaccine (ISV) is a promising immunotherapeutic tactic due to its complete tumoral antigenic repertoire. However, its efficiency is limited by extrinsic inevitable immunosuppression and intrinsic immunogenicity scarcity. To break this plight, a tumor-activated and optically reinforced immunoscaffold (TURN) is exploited to trigger cancer immunoediting phases regression, thus levering potent systemic antitumor immune responses. Upon response to tumoral reactive oxygen species, TURN will first release RGX-104 to attenuate excessive immunosuppressive cells and cytokines, and thus immunosuppression falls and immunogenicity rises. Subsequently, intermittent laser irradiation-activated photothermal agents (PL) trigger abundant tumor antigens exposure, which causes immunogenicity springs and preliminary infiltration of T cells. Finally, CD137 agonists from TURN further promotes the proliferation, function, and survival of T cells for durable antitumor effects. Therefore, cancer immunoediting phases reverse and systemic antitumor immune responses occur. TURN achieves over 90 % tumor growth inhibition in both primary and secondary tumor lesions, induces potent systemic immune responses, and triggers superior long-term immune memory in vivo. Taken together, TURN provides a prospective sight for ISV from the perspective of immunoediting phases.

Transformable Supramolecular Self-Assembled Peptides for Cascade Self-Enhanced Ferroptosis Primed Cancer Immunotherapy

Immunotherapy has received widespread attention for its effective and long-term tumor-eliminating ability. However, for immunogenic "cold" tumors, such as prostate cancer (PCa), the low immunogenicity of the tumor itself is a serious obstacle to efficacy. Here, this work reports a strategy to enhance PCa immunogenicity by triggering cascade self-enhanced ferroptosis in tumor cells, turning the tumor from "cold" to "hot". This work develops a transformable self-assembled peptide TEP-FFG-CRApY with alkaline phosphatase (ALP) responsiveness and glutathione peroxidase 4 (GPX4) protein targeting. TEP-FFG-CRApY self-assembles into nanoparticles under aqueous conditions and transforms into nanofibers in response to ALP during endosome/lysosome uptake into tumor cells, promoting lysosomal membrane permeabilization (LMP). On the one hand, the released TEP-FFG-CRAY nanofibers target GPX4 and selectively degrade the GPX4 protein under the light irradiation, inducing ferroptosis; on the other hand, the large amount of leaked Fe2+ further cascade to amplify the ferroptosis through the Fenton reaction. TEP-FFG-CRApY-induced immunogenic ferroptosis improves tumor cell immunogenicity by promoting the maturation of dendritic cells (DCs) and increasing intratumor T-cell infiltration. More importantly, recovered T cells further enhance ferroptosis by secreting large amounts of interferon-gamma (IFN-γ). This work provides a novel strategy for the molecular design of synergistic molecularly targeted therapy for immunogenic "cold" tumors.

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.