Combining immune checkpoint blockade with ATP-based immunogenic cell death amplifier for cancer chemo-immunotherapy

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

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

Enhancing immunogenicity and release of in situ-generated tumor vesicles for autologous vaccines

In situ vaccination (ISV) strategies offer an innovative approach to cancer immunotherapy by utilizing drug combinations directly at tumor sites to elicit personalized immune responses. Tumor cell-derived extracellular vesicles (TEVs) in ISV have great potential but face challenges such as low release rates and immunosuppressive proteins like programmed death ligand 1 (PD-L1) and CD47. This study develops a nanoparticle-based ISV strategy (Combo-NPs@shGNE) that enhances TEV release and modulates cargo composition. This approach combines Andrographolide, Icariside II, and shRNA targeting UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), which accumulates in the tumor region, resulting in the regulation of immunosuppressive pathways and the reduction of sialic acid production. Decreasing the level of sialylation on the membrane through necroptosis and inhibition of sialic acid synthesis decreased the loading of PD-L1 and CD47 on vesicles, while increasing the loading of heat shock protein 70 and high mobility group box 1 on vesicles, and induced the release of highly immunogenic TEVs from the cancer cells, with a 56.44 % release, 9.57 times higher than that of blank nanoparticle-treated cells. In vivo studies demonstrate that Combo-NPs@shGNE enhances TEV yield, tumor growth, reduces metastases, and improves survival in an osteosarcoma mouse model. It promotes dendritic cell maturation, increases CD4+ and CD8+ T cell infiltration, and alters the microenvironment by reducing myeloid-derived suppressor cells and enhancing immunostimulatory factors. Additionally, it transitions tumor-associated macrophages from M2 to an M1 phenotype, thereby augmenting tumor immunity. Overall, Combo-NPs@shGNE offers a promising method for transforming tumors into personalized autologous vaccines, potentially advancing cancer treatment strategies.

Construction of multifunctional nanozymes with amplified immunogenic death effect as a long-term anti-tumor nanoplatform

Stimulating the immunogenic cell death (ICD) effect is a method of tumor treatment through activating immunity. While conventional approaches including chemotherapy, photothermal therapy (PTT), and chemodynamic therapy (CDT), demonstrate partial ICD induction capabilities, their efficacy in eliciting systemic immune responses remains constrained by the immunosuppressive tumor microenvironment. Herein, a trimetallic nanozyme (Mn/Fe-MIL-101/CuS/DOX@FA) was engineered through the integration of Mn-doped Fe-MOFs, CuS, doxorubicin (DOX, 35.08 mg/g), and folic acid (FA). The design leverages the synergistic effects of Mn(II), Fe(III), and Cu(II), combined with the photothermal performance of CuS, which collectively enhance glutathione peroxidase (GPx)-like and peroxidase (POD)-like activities. This catalytic cascade depletes glutathione and boosts hydroxyl radicals via Fenton-like reactions, thereby disrupting redox balance to amplify chemodynamic therapy. CuS-mediated photothermal effects coupled with pH/GSH-responsive DOX release further augment ICD, effectively reversing immunosuppression. In vivo evaluations demonstrated 57 % inhibition of the primary tumor and 66.7 % inhibition of the distant tumor, confirming its efficacy in tumor treatment and prevention of recurrence/metastasis. Besides, magnetic resonance imaging experiments showed the T1/T2 dual-mode imaging performance. Thereby, a long-term anti-tumor nanoplatform is constructed through dual-mode imaging-guided multimodal therapy, which integrates tumor diagnosis, treatment, and prevention of recurrence and metastasis.

Leveraging adenosine triphosphate for cancer theranostics

Manipulation of the biochemical composition of the tumor microenvironment (TME) is a thriving research area in cancer treatment. Adenosine triphosphate (ATP), a key biochemical component, serves as an energy source for cancer cell proliferation. Notably, ATP can also act as a potent signal transducer to prime anti-tumor immune responses. There is increasing attention given to both the tumor-promoting and tumor-inhibiting roles of ATP in the context of possible new treatments for cancer. ATP levels in the TME are known to be significantly greater than in non-tumor tissues. This disparity presents an opportunity to exploit the ATP response for the delivery of anti-tumor drugs and tumor diagnosis. In this article, we provide a comprehensive overview of the existing strategies and mechanisms for ATP-based therapy and cancer diagnosis. We also discuss the current challenges in the field and propose potential areas for future research, to provide researchers with insights to further investigate the potential of ATP in cancer theranostics.

Transferrin-Based Bismuth Nanoparticles for Radiotherapy with Immunomodulation Against Orthotopic Glioma

Modern radiotherapy frequently employs radiosensitizers for radiation dose deposition and triggers an immunomodulatory effect to enhance tumor destruction. However, developing glioma-targeted sensitizers remains challenging due to the blood-brain barrier (BBB) and multicomponent instability. This study aims to green-synthesize transferrin-bismuth nanoparticles (TBNPs) as biosafe radiosensitizers to enhance X-ray absorption by tumors and stimulate the immune response for glioma therapy. The proposed protein-based strategy provides TBNPs with BBB-crossing ability and prevents off-target toxicity. Cellular experiments following 4 Gy of X-ray irradiation reveal that TBNPs increase DNA damage in glioma cells and trigger immunomodulation, thereby inducing immunogenic cell death. Furthermore, TBNPs effectively inhibit tumor growth through synergistic radiotherapy and immunotherapy in an orthotopic glioma mouse model. The findings highlight TBNPs as promising radiosensitizers for effective and biosafe radiotherapy with immunomodulation.

Molecular Subtyping and Therapeutic Targeting of IFNG-Driven Immunogenic Cell Death in Lung Adenocarcinoma

BACKGROUND

Immunogenic cell death (ICD) can be triggered by various therapies to induce anti-tumor immune responses, significantly enhancing treatment effectiveness, and is widely utilized in tumor immunotherapy.

METHODS

LUAD data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) validated ICD-related molecular subtypes via consensus clustering. Clinical features, ICD genes, driver genes, mutations, tumor microenvironment, immune checkpoints, and drug sensitivity were compared. RT-qPCR, Western blot, immunofluorescence, ELISA, flow cytometry, and tube formation assays validated findings.

RESULTS

Differential expression of 33 ICD genes was observed between tumor and normal tissues. These genes were clustered into two groups via consensus clustering and validated with GEO data. Prognostic analysis indicated superior outcomes in cluster 2 across TCGA and GEO cohorts. Significant disparities in clinicopathological characteristics like stage, gender, and age were noted between subtypes. Cluster 2 exhibited heightened expression of ICD-related genes, driver genes, immune checkpoints, and immune cells. Cluster 2 also showed increased sensitivity to chemotherapy drugs. IFNG overexpression in A549 and H1299 cells induced CRT exposure, HMGB1 release, and ATP secretion, thereby promoting dendritic cell maturation and enhancing CD8+ T cell function. Additionally, IFNG boosted tumor angiogenesis via HMGB1 pathways, which could be mitigated by HMGB1 inhibition.

CONCLUSION

Identification of novel ICD-related molecular subtypes holds promise for guiding personalized therapies, assessing prognosis, and predicting immunotherapy efficacy in LUAD. IFNG emerges as a potential prognostic biomarker and therapeutic target, influencing both the tumor microenvironment and angiogenesis. These findings offer new insights into therapeutic strategies targeting IFNG-mediated pathways in LUAD.

Iron Oxide Nanoparticles Induce Macrophage Secretion of ATP and HMGB1 to Enhance Irradiation-Led Immunogenic Cell Death

ATP (adenosine triphosphate) and HMGB1 (high mobility group box 1 protein) are key players in treatments that induce immunogenic cell death (ICD). However, conventional therapies, including radiotherapy, are often insufficient to induce ICD. In this study, we explore a strategy using nanoparticle-loaded macrophages as a source of ATP and HMGB1 to complement radiation-induced intrinsic and adaptive immune responses. To this end, we tested three inorganic particles, namely, iron oxide nanoparticles (ION), aluminum oxide nanoparticles (AON), and zinc oxide nanoparticles (ZON), in vitro with bone marrow-derived dendritic cells (BMDCs) and then in vivo in syngeneic tumor models. Our results showed that ION was the most effective of the three nanoparticles in promoting the secretion of ATP and HMGB1 from macrophages without negatively affecting macrophage survival. Secretions from ION-loaded macrophages can activate BMDCs. Intratumoral injection of ION-loaded macrophages significantly enhanced tumor infiltration and activation of dendritic cells and cytotoxic T cells. Moreover, exogenous ION macrophages can enhance the efficacy of radiotherapy. In addition, direct injection of ION can also enhance the efficacy of radiotherapy, which is attributed to ION uptake by and stimulation of endogenous macrophages. Instead of directly targeting cancer cells, our strategy targets macrophages and uses them as a secretory source of ATP and HMGB1 to enhance radiation-induced ICD. Our research introduces a new nanoparticle-based immunomodulatory approach that may have applications in radiotherapy and beyond.

Immunogenic cell death: A new strategy to enhancing cancer immunotherapy

Immunogenic cell death (ICD) is a distinct type of stress-induced regulated cell death that can lead to adaptive immune responses and the establishment of immunological memory. ICD exhibits both similarities and differences when compared to apoptosis and other non-apoptotic forms of regulated cell death (RCD). The interplay between ICD-mediated immunosurveillance against cancer and the ability of cancer cells to evade ICD influences the host-tumor immunological interaction. Consequently, the restoration of ICD and the development of effective strategies to induce ICD have emerged as crucial considerations in the treatment of cancer within the context of immunotherapy. To enhance comprehension of ICD in the setting of cancer, this paper examines the interconnected responsive pathways associated with ICD, the corresponding biomarkers indicative of ICD, and the mechanisms through which tumors subvert ICD. Additionally, this review explores strategies for reinstating ICD and the therapeutic potential of harnessing ICD in cancer immunotherapy.

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.

An encounter between metal ions and natural products: natural products-coordinated metal ions for the diagnosis and treatment of tumors

Natural products-coordinated metal ions to form the nanomedicines are in the spotlight for cancer therapy. Some natural products could be coordinated with metal ions forming nanomedicines via simple and green environmental self-assembly, which not only improved the bioavailability of natural products, but also conferred multiple therapeutic modalities and multimodal imaging. On the one hand, in the weak acidity, glutathione (GSH) and hydrogen peroxide (H2O2) overexpression of tumor microenvironment (TME), such carrier-free nanomedicines could be further enhanced the therapeutic effect via optimizing the species of metal ions. On the other hand, nanomedicines could exert the precise treatment of tumor under the guidance of multiple imaging. Hence, this review summarized the research progress in recent years on the application of natural product-coordinated metal ions in cancer therapy. In addition, the prospects and challenges for the application of natural product-coordinated metal ions were discussed, especially how to improve targeting ability and stability and assess the safety of metal ions, so as to facilitate the clinical translation and application of natural product-coordinated metal ions nanomedicines.

Muramyl Dipeptide-Presenting Polymersomes as Artificial Nanobacteria to Boost Systemic Antitumor Immunity

The clinical efficacy of cancer vaccines is closely related to immunoadjuvants that play a crucial role in magnifying and prolonging the immune response. Muramyl dipeptide (MDP), a minimal and conserved peptidoglycan found in almost all bacteria, can trigger robust immune activation by uniquely antagonizing the nucleotide-binding oligomerization domain 2 (NOD2) pathway. However, its effectiveness has been hindered by limited solubility, poor membrane penetration, and rapid clearance from the body. Here, we introduce MDP-presenting polymersomes as artificial nanobacteria (NBA) to boost the antitumor immune response. The NBA, featuring abundant MDP molecules, induces superior stimulation of immune cells including macrophages and bone marrow-derived dendritic cells (BMDCs) compared to free MDP, likely via facilitating immune cell uptake and cooperatively stimulating systemic NOD2 signaling. Importantly, systemic administration of NBA significantly enhances the chemo-immunotherapy of B16-F10 melanoma-bearing mice pretreated with doxorubicin by reversing the immunosuppressive tumor microenvironment. Furthermore, NBA carrying ovalbumin and B16-F10 cell lysates induces robust OVA-IgG antibody production and effectively inhibit tumor growth, respectively. The artificial nanobacteria hold great promise as a potent systemic immunoadjuvant for cancer immunotherapy.

A personalized vaccine combining immunogenic cell death-induced cells and nanosized antigens for enhanced antitumor immunity

The tumor vaccine aims to activate the immune system, promote antitumor cellular responses, and restore immune recognition and clearance of tumor cells. However, the low immunogenicity and heterogeneity of tumor antigens, along with immunosuppressive mechanisms, severely hinder tumor vaccines from achieving an efficient and sustained antitumor effect. Herein, we developed a combined vaccine strategy that utilizes immunogenic cell death (ICD) to elicit a broad spectrum of antigen-specific responses in a whole-cell-based manner. Additionally, we introduced nanosized antigens to intensify immune responses targeting a key tumor antigen. The combination of mitoxantrone (MTX) and curcumin (Cur) optimized ICD properties in TC-1 tumor cells, as evidenced by increased release of "find me" signals, such as HMGB1 and ATP, and enhanced exposure of the "eat me" signal, CALR, compared to either MTX or Cur alone. Correspondingly, the ICD cells induced by the combination produced more significant antitumor effects in vivo. Furthermore, the ICD cells in combination with E7-HBcAg VLPs or E7-Q11 nanofibers induced more intense effector cell responses to the antigen included in the nanovaccines, as well as a broad spectrum of antigens provided by tumor cells, and significantly suppressed the growth of established tumors compared with either ICD cells, VLPs, or nanofibers alone. In conclusion, the combination of ICD cells and nanosized antigens produced synergistic antitumor effects and elicited robust and comprehensive antitumor immunity, presenting an attractive strategy for developing personalized tumor vaccines.

Matrix metalloproteinase 2-responsive dual-drug-loaded self-assembling peptides suppress tumor growth and enhance breast cancer therapy

Conventional chemotherapeutic agents are limited by their lack of targeting and penetration and their short retention time, and chemotherapy might induce an immune suppressive environment. Peptide self-assembly can result in a specific morphology, and the resulting morphological changes are stimuli responsive to the external environment, which is important for drug permeation and retention of encapsulated chemotherapeutic agents. In this study, a polypeptide (Pep1) containing the peptide sequences PLGLAG and RGD that is responsive to matrix metalloproteinase 2 (MMP-2) was successfully developed. Pep1 underwent a morphological transformation from a spherical structure to aggregates with a high aspect ratio in response to MMP-2 induction. This drug delivery system (DI/Pep1) can transport doxorubicin (DOX) and indomethacin (IND) simultaneously to target tumor cells for subsequent drug release while extending drug retention within tumor cells, which increases immunogenic cell death and facilitates the immunotherapeutic effect of CD4+ T cells. Ultimately, DI/Pep1 attenuated tumor-associated inflammation, enhanced the body's immune response, and inhibited breast cancer growth by combining the actions of DOX and IND. Our research offers an approach to hopefully enhance the effectiveness of cancer treatment.

Inorganic Nanoparticle Functionalization Strategies in Immunotherapeutic Applications

Nanotechnology has been increasingly utilized in anticancer treatment owing to its ability of engineering functional nanocarriers that enhance therapeutic effectiveness while minimizing adverse effects. Inorganic nanoparticles (INPs) are prevalent nanocarriers to be customized for a wide range of anticancer applications, including theranostics, imaging, targeted drug delivery, and therapeutics, because they are advantageous for their superior biocompatibility, unique optical properties, and capacity of being modified via versatile surface functionalization strategies. In the past decades, the high adaptation of INPs in this emerging immunotherapeutic field makes them good carrier options for tumor immunotherapy and combination immunotherapy. Tumor immunotherapy requires targeted delivery of immunomodulating therapeutics to tumor locations or immunological organs to provoke immune cells and induce tumor-specific immune response while regulating immune homeostasis, particularly switching the tumor immunosuppressive microenvironment. This review explores various INP designs and formulations, and their employment in tumor immunotherapy and combination immunotherapy. We also introduce detailed demonstrations of utilizing surface engineering tactics to create multifunctional INPs. The generated INPs demonstrate the abilities of stimulating and enhancing the immune response, specific targeting, and regulating cancer cells, immune cells, and their resident microenvironment, sometimes along with imaging and tracking capabilities, implying their potential in multitasking immunotherapy. Furthermore, we discuss the promises of INP-based combination immunotherapy in tumor treatments.

Gold Nano Frameworks with Mesopores for Synergistic Immune-Thermal Therapy in Hepatic Carcinoma: A Paradigm Shift in Immune Checkpoint Blockade

Immune checkpoint blockade (ICB) therapy, while showing promise in various cancers, exhibits limited effectiveness in hepatic carcinoma due to the tumor's immunosuppressive microenvironment (TME) and challenges associated with immune cell infiltration. Efforts to transform the "cold" TME into an "inflamed" state, notably through chemo-immunotherapy, have sparked interest due to their potential to induce immunogenic cell death and augment the infiltration of cytotoxic T lymphocytes (CTLs). Nonetheless, the efficacy of chemo-immunotherapy is often compromised by suboptimal pharmacokinetics, poor tumor accumulation, and off-target toxicity. Herein, in response, we introduce an innovative, milder thermal therapeutic approach leveraging gold nano frameworks with mesopores for the targeted delivery of the immunostimulant imiquimod and NIR-II photothermal therapy. This strategy employs targeted molecule modifications to ensure precise tumor targeting, guided by photoacoustic imaging. Subsequent to mild thermal treatment, there is a release of immunogenic proteins (CRT and HSP90), enhancing tumor immunogenicity. Assisted by imiquimod, substantial CTL infiltration occurs, accompanied by pro-inflammatory factor release (TNF-α, IL-6), transforming M2 macrophages into the M1 phenotype. Ultimately, the proposed strategy combines PD-L1/PD-1 blockade, imiquimod and mild thermal treatment to synergistically enhance tumor immunogenicity, remodel the TME, and restrain hepatic carcinoma, making strides in ICB synergistic immune-thermal therapy.

Rhodium(III) Complex Noncanonically Potentiates Antitumor Immune Responses by Inhibiting Wnt/β-Catenin Signaling

Metal-based chemoimmunotherapy has recently garnered significant attention for its capacity to stimulate tumor-specific immunity beyond direct cytotoxic effects. Such effects are usually caused by ICD via the activation of DAMP signals. However, metal complexes that can elicit antitumor immune responses other than ICD have not yet been described. Herein, we report that a rhodium complex (Rh-1) triggers potent antitumor immune responses by downregulating Wnt/β-catenin signaling with subsequent activation of T lymphocyte infiltration to the tumor site. The results of mechanistic experiments suggest that ROS accumulation following Rh-1 treatment is a critical trigger of a decrease in β-catenin and enhanced secretion of CCL4, a key mediator of T cell infiltration. Through these properties, Rh-1 exerts a synergistic effect in combination with PD-1 inhibitors against tumor growth in vivo. Taken together, our work describes a promising metal-based antitumor agent with a noncanonical mode of action to sensitize tumor tissues to ICB therapy.

Endoplasmic reticulum-targeted delivery of celastrol and PD-L1 siRNA for reinforcing immunogenic cell death and potentiating cancer immunotherapy

The prospect of employing chemoimmunotherapy targeted towards the endoplasmic reticulum (ER) presents an opportunity to amplify the synergistic effects of chemotherapy and immunotherapy. In this study, we initially validated celastrol (CEL) as an inducer of immunogenic cell death (ICD) by promoting ER stress and autophagy in colorectal cancer (CRC) cells. Subsequently, an ER-targeted strategy was posited, involving the codelivery of CEL with PD-L1 small interfering RNAs (siRNA) using KDEL peptide-modified exosomes derived from milk (KME), to enhance chemoimmunotherapy outcomes. Our findings demonstrate the efficient transportation of KME to the ER via the Golgi-to-ER pathway. Compared to their non-targeting counterparts, KME exhibited a significant augmentation of the CEL-induced ICD effect. Additionally, it facilitated the release of danger signaling molecules (DAMPs), thereby stimulating the antigen-presenting function of dendritic cells and promoting the infiltration of T cells into the tumor. Concurrently, the ER-targeted delivery of PD-L1 siRNA resulted in the downregulation of both intracellular and membrane PD-L1 protein expression, consequently fostering the proliferation and activity of CD8+ T cells. Ultimately, the ER-targeted formulation exhibited enhanced anti-tumor efficacy and provoked anti-tumor immune responses against orthotopic colorectal tumors in vivo. Collectively, a robust ER-targeted delivery strategy provides an encouraging approach for achieving potent cancer chemoimmunotherapy.

Advancements in nanomedicine delivery systems: unraveling immune regulation strategies for tumor immunotherapy

This review highlights the significant role of nanodrug delivery systems (NDDS) in enhancing the efficacy of tumor immunotherapy. Focusing on the integration of NDDS with immune regulation strategies, it explores their transformative impacts on the tumor microenvironment and immune response dynamics. Key advancements include the optimization of drug delivery through NDDS, targeting mechanisms like immune checkpoint blockade and modulating the immunosuppressive tumor environment. Despite the progress, challenges such as limited clinical efficacy and complex manufacturing processes persist. The review emphasizes the need for further research to optimize these systems, potentially revolutionizing cancer treatment by improving delivery efficiency, reducing toxicity and overcoming immune resistance.

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.

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.

Inhalable metal-organic framework-mediated cuproptosis combined with PD-L1 checkpoint blockade for lung metastasis synergistic immunotherapy

Cuproptosis shows enormous application prospects in lung metastasis treatment. However, the glycolysis, Cu+ efflux mechanisms, and insufficient lung drug accumulation severely restrict cuproptosis efficacy. Herein, an inhalable poly (2-(N-oxide-N,N-diethylamino)ethyl methacrylate) (OPDEA)-coated copper-based metal-organic framework encapsulating pyruvate dehydrogenase kinase 1 siRNA (siPDK) is constructed for mediating cuproptosis and subsequently promoting lung metastasis immunotherapy, namely OMP. After inhalation, OMP shows highly efficient lung accumulation and long-term retention, ascribing to the OPDEA-mediated pulmonary mucosa penetration. Within tumor cells, OMP is degraded to release Cu2+ under acidic condition, which will be reduced to toxic Cu+ to induce cuproptosis under glutathione (GSH) regulation. Meanwhile, siPDK released from OMP inhibits intracellular glycolysis and adenosine-5'-triphosphate (ATP) production, then blocking the Cu+ efflux protein ATP7B, thereby rendering tumor cells more sensitive to OMP-mediated cuproptosis. Moreover, OMP-mediated cuproptosis triggers immunogenic cell death (ICD) to promote dendritic cells (DCs) maturation and CD8+ T cells infiltration. Notably, OMP-induced cuproptosis up-regulates membrane-associated programmed cell death-ligand 1 (PD-L1) expression and induces soluble PD-L1 secretion, and thus synergizes with anti-PD-L1 antibodies (aPD-L1) to reprogram immunosuppressive tumor microenvironment, finally yielding improved immunotherapy efficacy. Overall, OMP may serve as an efficient inhalable nanoplatform and afford preferable efficacy against lung metastasis through inducing cuproptosis and combining with aPD-L1.

Harnessing PD-1 cell membrane-coated paclitaxel dimer nanoparticles for potentiated chemoimmunotherapy

Chemoimmunotherapy has emerged as a promising strategy for improving the efficacy of cancer treatment. Herein, we present PD-1 receptor-presenting membrane-coated paclitaxel dimers nanoparticles (PD-1@PTX2 NPs) for enhanced treatment efficacy. PD-1 cell membrane-cloaked PTX dimer exhibited effective cellular uptake and increased cytotoxicity against cancer cells. PD-1@PTX2 NPs could selectively bind with PD-L1 ligands expressed on breast cancer cells. Our nanoparticles exhibit a remarkable tumor growth inhibition rate of 71.3% in mice bearing 4T1 xenografts and significantly prolong survival in mouse models of breast cancer. Additionally, our nanoparticles promoted a significant 3.2-fold increase in CD8+ T cell infiltration and 73.7% regulatory T cell (Treg) depletion within tumors, boosting a robust antitumor immune response. These findings underscore the potential of utilizing immune checkpoint receptor-presented PTX nanoparticles to enhance the efficacy of chemoimmunotherapy, providing an alternative approach for improving cancer treatment.

MSLN induced EMT, cancer stem cell traits and chemotherapy resistance of pancreatic cancer cells

Chemoresistance is one of the main reasons for poor prognosis of pancreatic cancer. The effects of mesothelin (MSLN) on chemoresistance in pancreatic cancer are still unclear. We aim to investigate potential roles of MSLN in chemoresistance and its relationship with proliferation, epithelial-mesenchymal transition (EMT) and cancer stemness of pancreatic cancer cells. Human pancreatic cancer cell lines ASPC-1 and Mia PaCa-2 with high and low expression of MSLN, respectively, were selected. The ASPC-1 with MSLN knockout (KO) and Mia PaCa-2 of MSLN overexpression (OE) were generated. The effects of MSLN on cell phenotypes, expression of EMT-related markers, clone formation, tumor sphere formation, and pathologic role of MSLN in tumorigenesis were detected. Sensitivity of tumor cells to gemcitabine was evaluated. The results showed that adhesion, proliferation, migration and invasion were decreased significantly in ASPC-1 with MSLN KO, whereas increased significantly in Mia PaCa-2 with MSLN OE. The size and the number of clones and tumor spheres were decreased in ASPC-1 with MSLN KO, and increased in Mia PaCa-2 with MSLN OE. In xenograft model, tumor volume was decreased (tumor grew slower) in MSLN KO group compared to control group, while increased in MSLN OE group. Mia PaCa-2 with MSLN OE had a higher IC50 of gemcitabine, while ASPC-1 with MSLN KO had a lower IC50. We concluded that MSLN could induce chemoresistance by enhancing migration, invasion, EMT and cancer stem cell traits of pancreatic cancer cells. Targeting MSLN could represent a promising therapeutic strategy for reversing EMT and chemoresistance in pancreatic cancer cells.

Bimetallic nanoparticles as cascade sensitizing amplifiers for low-dose and robust cancer radio-immunotherapy

Radiotherapy (RT) is one of the most feasible and routinely used therapeutic modalities for treating malignant tumors. In particular, immune responses triggered by RT, known as radio-immunotherapy, can partially inhibit the growth of distantly spreading tumors and recurrent tumors. However, the safety and efficacy of radio-immunotherapy is impeded by the radio-resistance and poor immunogenicity of tumor. Herein, we report oxaliplatin (IV)-iron bimetallic nanoparticles (OXA/Fe NPs) as cascade sensitizing amplifiers for low-dose and robust radio-immunotherapy. The OXA/Fe NPs exhibit tumor-specific accumulation and activation of OXA (II) and Fe2+ in response to the reductive and acidic microenvironment within tumor cells. The cascade reactions of the released metallic drugs can sensitize RT by inducing DNA damage, increasing ROS and O2 levels, and amplifying the immunogenic cell death (ICD) effect after RT to facilitate potent immune activation. As a result, OXA/Fe NPs-based low-dose RT triggered a robust immune response and inhibited the distant and metastatic tumors effectively by a strong abscopal effect. Moreover, a long-term immunological memory effect to protect mice from tumor rechallenging is observed. Overall, the bimetallic NPs-based cascade sensitizing amplifier system offers an efficient radio-immunotherapy regimen that addresses the key challenges.

Immunogenic dead cells engineered by the sequential treatment of ultraviolet irradiation/cryo-shocking for lung-targeting delivery and tumor vaccination

Chemoimmunotherapy is a promising strategy in tumor treatments. In this study, immunogenic dead cells were engineered by the sequential treatment of live tumor cells with ultraviolet (UV) irradiation and cryo-shocking. The dead cells could serve as a lung-targeting vehicle and tumor vaccine after differential loading of the chemo-drug 10-hydroxycamptothecin (HCPT) and immune adjuvant Quillaja saponin-21 (QS-21) via physical absorption and chemical conjugation, respectively. After intravenous administration, the dead cells could be trapped in pulmonary capillaries and could fast release HCPT to enhance the drug accumulation in local tissues. Further, the immunogenic dead cells elicited antitumor immune responses together with the conjugated adjuvant QS-21 to achieve the elimination and long-term surveillance of tumor cells. In a lung tumor-bearing mice model, this drug-delivery system achieved synergistic antitumor efficacy and prolonged the survival of mice.

Enhanced therapeutic efficacy of doxorubicin against multidrug-resistant breast cancer with reduced cardiotoxicity

Doxorubicin (DOX), a commonly used anti-cancer drug, is limited by its cardiotoxicity and multidrug resistance (MDR) of tumor cells. Epigallocatechin gallate (EGCG), a natural antioxidant component, can effectively reduce the cardiotoxicity of DOX. Meanwhile, EGCG can inhibit the expression of P-glycoprotein (P-gp) and reverse the MDR of tumor cells. In this study, DOX is connected with low molecular weight polyethyleneimine (PEI) via hydrazone bond to get the pH-sensitive PEI-DOX, which is then combined with EGCG to prevent the cardiotoxicity of DOX and reverse the MDR of cancer cells. In addition, folic acid (FA) modified polyethylene glycol (PEG) (PEG-FA) is added to get the targeted system PEI-DOX/EGCG/FA. The MDR reversal and targeting ability of PEI-DOX/EGCG/FA is performed by cytotoxicity and in vivo anti-tumor activity on multidrug resistant MCF-7 cells (MCF-7/ADR). Additionally, we investigate the anti-drug resistant mechanism by Western Blot. The ability of EGCG to reduce DOX cardiotoxicity is confirmed by cardiotoxicity assay. In conclusion, PEI-DOX/EGCG/FA can inhibit the expression of P-gp and reverse the MDR in tumor cells. It also shows the ability of remove oxygen free radicals effectively to prevent the cardiotoxicity of DOX.

Antitumor synergism between PAK4 silencing and immunogenic phototherapy of engineered extracellular vesicles

Immunotherapy has revolutionized the landscape of cancer treatment. However, single immunotherapy only works well in a small subset of patients. Combined immunotherapy with antitumor synergism holds considerable potential to boost the therapeutic outcome. Nevertheless, the synergistic, additive or antagonistic antitumor effects of combined immunotherapies have been rarely explored. Herein, we established a novel combined cancer treatment modality by synergizing p21-activated kinase 4 (PAK4) silencing with immunogenic phototherapy in engineered extracellular vesicles (EVs) that were fabricated by coating M1 macrophage-derived EVs on the surface of the nano-complex cores assembled with siRNA against PAK4 and a photoactivatable polyethyleneimine. The engineered EVs induced potent PAK4 silencing and robust immunogenic phototherapy, thus contributing to effective antitumor effects in vitro and in vivo. Moreover, the antitumor synergism of the combined treatment was quantitatively determined by the CompuSyn method. The combination index (CI) and isobologram results confirmed that there was an antitumor synergism for the combined treatment. Furthermore, the dose reduction index (DRI) showed favorable dose reduction, revealing lower toxicity and higher biocompatibility of the engineered EVs. Collectively, the study presents a synergistically potentiated cancer treatment modality by combining PAK4 silencing with immunogenic phototherapy in engineered EVs, which is promising for boosting the therapeutic outcome of cancer immunotherapy.

Nanoparticle-based drug delivery systems to enhance cancer immunotherapy in solid tumors

Immunotherapy has developed rapidly in solid tumors, especially in the areas of blocking inhibitory immune checkpoints and adoptive T-cell transfer for immune regulation. Many patients benefit from immunotherapy. However, the response rate of immunotherapy in the overall population are relatively low, which depends on the characteristics of the tumor and individualized patient differences. Moreover, the occurrence of drug resistance and adverse reactions largely limit the development of immunotherapy. Recently, the emergence of nanodrug delivery systems (NDDS) seems to improve the efficacy of immunotherapy by encapsulating drug carriers in nanoparticles to precisely reach the tumor site with high stability and biocompatibility, prolonging the drug cycle of action and greatly reducing the occurrence of toxic side effects. In this paper, we mainly review the advantages of NDDS and the mechanisms that enhance conventional immunotherapy in solid tumors, and summarize the recent advances in NDDS-based therapeutic strategies, which will provide valuable ideas for the development of novel tumor immunotherapy regimen.

Trial watch: chemotherapy-induced immunogenic cell death in oncology

Immunogenic cell death (ICD) refers to an immunologically distinct process of regulated cell death that activates, rather than suppresses, innate and adaptive immune responses. Such responses culminate into T cell-driven immunity against antigens derived from dying cancer cells. The potency of ICD is dependent on the immunogenicity of dying cells as defined by the antigenicity of these cells and their ability to expose immunostimulatory molecules like damage-associated molecular patterns (DAMPs) and cytokines like type I interferons (IFNs). Moreover, it is crucial that the host's immune system can adequately detect the antigenicity and adjuvanticity of these dying cells. Over the years, several well-known chemotherapies have been validated as potent ICD inducers, including (but not limited to) anthracyclines, paclitaxels, and oxaliplatin. Such ICD-inducing chemotherapeutic drugs can serve as important combinatorial partners for anti-cancer immunotherapies against highly immuno-resistant tumors. In this Trial Watch, we describe current trends in the preclinical and clinical integration of ICD-inducing chemotherapy in the existing immuno-oncological paradigms.

cRGD-modified nanoparticles of multi-bioactive agent conjugate with pH-sensitive linkers and PD-L1 antagonist for integrative collaborative treatment of breast cancer

Targeted co-delivery and co-release of multi-drugs is essential to have an integrative collaborative effect on treating cancer. It is valuable to use few drug carriers for multi-drug delivery. Herein, we develop cRGD-modified nanoparticles (cRGD-TDA) of a conjugate of doxorubicin as cytotoxic agent, adjudin as an anti-metastasis agent and D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as a reactive oxygen species inducer linked with pH-sensitive bonds, and then combine the nanoparticles with PD-L1 antagonist to treat 4T1 triple-negative breast cancer. cRGD-TDA NPs present tumor-targeted co-delivery and pH-sensitive co-release of triple agents. cRGD-TDA NPs combined with PD-L1 antagonist much more significantly inhibit tumor growth and metastasis than single-drug treatment, which is due to their integrative collaborative effect. It is found that TPGS elicits a powerful immunogenic cell death effect. Meanwhile, PD-L1 antagonist mitigates the immunosuppressive environment and has a synergistic effect with the cRGD-TDA NPs. The study provides a new strategy to treat refractory cancer integratively and collaboratively.

Nanomaterials: small particles show huge possibilities for cancer immunotherapy

With the economy's globalization and the population's aging, cancer has become the leading cause of death in most countries. While imposing a considerable burden on society, the high morbidity and mortality rates have continuously prompted researchers to develop new oncology treatment options. Anti-tumor regimens have evolved from early single surgical treatment to combined (or not) chemoradiotherapy and then to the current stage of tumor immunotherapy. Tumor immunotherapy has undoubtedly pulled some patients back from the death. However, this strategy of activating or boosting the body's immune system hardly benefits most patients. It is limited by low bioavailability, low response rate and severe side effects. Thankfully, the rapid development of nanotechnology has broken through the bottleneck problem of anti-tumor immunotherapy. Multifunctional nanomaterials can not only kill tumors by combining anti-tumor drugs but also can be designed to enhance the body's immunity and thus achieve a multi-treatment effect. It is worth noting that the variety of nanomaterials, their modifiability, and the diversity of combinations allow them to shine in antitumor immunotherapy. In this paper, several nanobiotics commonly used in tumor immunotherapy at this stage are discussed, and they activate or enhance the body's immunity with their unique advantages. In conclusion, we reviewed recent advances in tumor immunotherapy based on nanomaterials, such as biological cell membrane modification, self-assembly, mesoporous, metal and hydrogels, to explore new directions and strategies for tumor immunotherapy.