Cancer immunogenic cell death via photo-pyroptosis with light-sensitive Indoleamine 2,3-dioxygenase inhibitor conjugate

Graphitic carbon nitride/methyl pyrophaeophorbide a-copper/folate nanoconjugate for enhanced immunogenic death combined with PD-L1 immune checkpoint blockades

Immune checkpoint blockade (ICB) is a tumor therapy that leverages the activation mechanisms of T cells in the immune system. A key challenge in ICB is poor T-cell infiltration and low tumor immunogenicity. Immunogenic cell death (ICD) can increase tumor immunogenicity and make tumors more sensitive to ICB. Programmed death ligand 1 (PD-L1) a major target for ICB. In this paper, a novel carbon nitride/methyl pyrophaeophorbide a‑copper/folate (abbreviated as CNMCF) nanocomposite was prepared for induced ICD. In CNMCF nanostructures, methyl pyrophaeophorbide a (MPPa) serves as the photodynamic therapy (PDT) agent, and copper ion serves as the chemodynamic therapy (CDT) agent. CNMCF not only induced ICD, but also alleviated tumor hypoxia. This led to down-regulation of hypoxia-inducing factor (HIF-1α) and PD-L1, promoted T lymphocyte invasion, effectively enhanced tumor immunogenicity, and elicited strong anti-tumor immune response, thereby suppressing primary tumor growth and metastasis. This research expanded the application of natural chlorophyll derivatives and C3N4-based drug delivery systems in cancer immunotherapy.

Regulated cell death mechanisms in mitochondria-targeted phototherapy

Phototherapy, comprising photodynamic therapy (PDT) and photothermal therapy (PTT), was first introduced over a century ago and has since evolved into a versatile cancer treatment modality. While numerous studies have explored regulated cell death (RCD) mechanisms induced by phototherapy, a comprehensive synthesis centered on mitochondria-targeted phototherapeutic strategies and agents as mediators of RCD is still lacking. This review provides a systematic and in-depth analysis of recent advances in mitochondria-centered mechanisms driving phototherapy-induced death pathways, including apoptosis, autophagy, pyroptosis, immunogenic cell death, ferroptosis, and cuproptosis. We highlight the critical role of mitochondria as central regulators of these death pathways in response to phototherapeutic interventions. Moreover, we discuss fundamental design strategies for developing precision-targeted phototherapeutic materials to enhance efficacy and minimize off-target effects. Finally, we identify prevailing challenges and propose future research directions to address these hurdles, paving the way for next-generation mitochondria-targeted phototherapy as a highly effective strategy for cancer management.

Verteporfin-Mediated In Situ Nanovaccine Based on Local Conventional-Dose Hypofractionated Radiotherapy Enhances Antitumor and Immunomodulatory Effect

In situ radiotherapy is the most successful cytotoxic therapy available for the treatment of solid tumors, while high-dose radiotherapy per fraction is not yet widely and reliably used. To some extent, the major considerations of the disappointing results are on the risk of high-dose irradiation-induced damage to the surrounding normal tissues and the difficulty in distant metastasis control. To break these restraints, a gelatinase-responsive amphiphilic methoxypolyethyleneglycol-PVGLIG-polycaprolactone (mPEG-PVGLIG-PCL) nanoparticles' loading verteporfin (N@VP), a special photosensitizer that can also be excited by X-rays to produce cytotoxic singlet oxygen and greatly enhance radiotherapy efficacy, is prepared in this study. Herein, it is shown that the formed N@VP combined with conventional-dose radiation therapy (RT, 2 Gy (gray, a radiation dose unit)) can realize an antitumor effect no less than high-dose RT (8 Gy) and minimize radiation dose necessary to achieve local tumor control. Moreover, this radiosensitive nanosystem can exert excellent systemic antitumor immunity and abscopal effect, providing a preferable "in situ vaccine" strategy based on conventional-dose RT to achieve efficient systemic management of distant tumor metastasis. When combined with immunotherapy, this novel strategy for radiosensitization results in better immunotherapy sensitivity by stimulating significant immunogenic tumor cell death and synergistic antitumor immune responses.

Transforming malignant tumors into vulnerable phenotypes via nanoscale coordination polymer mediated cell senescence and photodynamic therapy

Induction of senescence in cancer cells can thwart the proliferation of malignant tumors. Herein we report the design of AZT-P/pyro nanoscale coordination polymer particles consisting of 3-azido-2,3-dideoxythymidine monophosphate (AZT-P) in the core and photosensitizing pyro-lipid (pyro) in the shell for potent antitumor treatment. Gradual release of AZT-P in response to an acidic tumor microenvironment transforms cancer cells with unlimited proliferation capacity into senescent cells that are vulnerable to reactive oxygen species (ROS). Pyro selectively induces ROS generation and immunogenic cell death of cancer cells upon light irradiation. Co-delivery of AZT-P and pyro in a single particle prolongs their blood circulation times and enhances their accumulation in tumors. Additionally, the induction of senescence and ROS generation both contribute to the recruitment of immune cells to the tumors, resulting in an effective immune response to inhibit the growth of large subcutaneous tumors and metastatic spread of orthotopic tumors.

Bimetallic peroxide-based nanotherapeutics for immunometabolic intervention and induction of immunogenic cell death to augment cancer immunotherapy

Immunotherapy has transformed cancer treatment, but its efficacy is often limited by the immunosuppressive characteristics of the tumor microenvironment (TME), which are predominantly influenced by the metabolism of cancer cells. Among these metabolic pathways, the indoleamine 2,3-dioxygenase (IDO) pathway is particularly crucial, as it significantly contributes to TME suppression and influences immune cell activity. Additionally, inducing immunogenic cell death (ICD) in tumor cells can reverse the immunosuppressive TME, thereby enhancing the efficacy of immunotherapy. Herein, we develop CGDMRR, a novel bimetallic peroxide-based nanodrug based on copper-cerium peroxide nanoparticles. These nanotherapeutics are engineered to mitigate tumor hypoxia and deliver therapeutics such as 1-methyltryptophan (1MT), glucose oxidase (GOx), and doxorubicin (Dox) in a targeted manner. The design aims to alleviate tumor hypoxia, reduce the immunosuppressive effects of the IDO pathway, and promote ICD. CGDMRR effectively inhibits the growth of 4T1 tumors and elicits antitumor immune responses by leveraging immunometabolic interventions and therapies that induce ICD. Furthermore, when CGDMRR is combined with a clinically certified anti-PD-L1 antibody, its efficacy in inhibiting tumor growth is enhanced. This improved efficacy extends beyond unilateral tumor models, also affecting bilateral tumors and lung metastases, due to the activation of systemic antitumor immunity. This study underscores CGDMRR's potential to augment the efficacy of PD-L1 blockade in breast cancer immunotherapy.

Activatable Photosensitizer Prodrug for Self-Amplified Immune Therapy Via Pyroptosis

Immunotherapy is a promising cancer treatment, but its application is hindered by tumors' low immunogenicity and the difficulty of immune cell infiltration. Here, to address above issues and achieve targeted tumor treatment, we designed the first activated small molecule photosensitizer immune-prodrug HDIM based on pyroptosis, and proposed a self-amplified immune therapy strategy (SITS) for enhanced tumor therapy. HDIM can be specifically activated by the tumor hypoxia and then simultaneously initiate immuno-therapy and photodynamic therapy (PDT)-induced pyroptosis with NIR laser irradiation. Mechanism study demonstrated that the immunogenicity in tumor can be significantly enhanced by HDIM-induced pyroptosis and immune cells are recruited, thus effectively amplifying the therapeutic effect of the released immune drugs. As proof of application, we have utilized HDIM for primary tumor and distant tumor therapy. And the experiment results showed that compared to current monotherapy as well as simple combination therapy, the photosensitizer prodrug HDIM exhibited much superior tumor treatment effect owing to its synchronous activation of pyroptosis and immuno-therapy in tumor.

A Dual Stimuli-Responsive Nanoimmunomodulator for Antitumor Synergy of Macrophages and T Cells

Only a minority of patients benefit from current T-cell-focused adaptive immunotherapies, underscoring the need to engage innate immune cells, particularly macrophages, for multilayered tumor control. However, high-efficacy therapeutics capable of orchestrating multiple immune cells remain scarce. Herein, a dual stimuli-responsive nanoimmunomodulator (6EPP@si) that caters specifically to the tumor microenvironment (TME) is presented for the antitumor synergy of macrophages and T cells. Using the functional polymer-based carrier, we co-deliver the endoplasmic reticulum (ER)-localized photosensitizer 6E and small interfering RNA targeting CD47 (siCD47) into breast tumors. Within the acidic and high-glutathione TME, 6EPP@si undergoes self-lysosome escape and nanocleavage for precise, on-demand drug release. Consequently, siCD47 released into the cytoplasm enables potent CD47 silencing, while the ER-targeted photosensitizer 6E induces immunogenic cell death through reactive oxygen species-based ER stress, triggering the release of damage-associated molecular patterns, including calreticulin surface translocation. 6EPP@si enhances macrophage phagocytosis by modulating both antiphagocytic and prophagocytic signals and also promotes antigen presentation to activate T cells. In orthotopic breast tumor and spontaneous lung metastatic tumor models, this combined approach demonstrates robust antitumor effects and effective antimetastatic immunity, offering a meaningful strategy to simultaneously activate multiple immune cells for enhancing cancer immunotherapy.

Ginger-Derived Exosome-Like Nanoparticles Loaded With Indocyanine Green Enhances Phototherapy Efficacy for Breast Cancer

PURPOSE

Phototherapy has remarkable advantages in cancer treatment, owing to its high efficiency and minimal invasiveness. Indocyanine green (ICG) plays an important role in photo-mediated therapy. However, it has several disadvantages such as poor stability in aqueous solutions, easy aggregation of molecules, and short plasma half-life. This study aimed to develop an efficient nanoplatform to enhance the effects of photo-mediated therapy.

METHODS

We developed a novel bio-nanoplatform by integrating edible ginger-derived exosome-like nanoparticles (GDNPs) and the photosensitizer, ICG (GDNPs@ICG). GDNPs were isolated from ginger juice and loaded with ICG by co-incubation. The size distribution, zeta potential, morphology, total lipid content, and drug release behavior of the GDNPs@ICG were characterized. The photothermal performance, cellular uptake and distribution, cytotoxicity, anti-tumor effects, and mechanism of action of GDNPs@ICG were investigated both in vitro and in vivo.

RESULTS

GDNPs@ICG were taken up by tumor cells via a lipid-dependent pathway. When irradiated by an 808 nm NIR laser, GDNPs@ICG generated high levels of ROS, MDA, and local hyperthermia within the tumor, which caused lipid peroxidation and ER stress, thus enhancing the photo-mediated breast tumor therapy effect. Furthermore, in vivo studies demonstrated that engineered GDNPs@ICG significantly inhibited breast tumor growth and presented limited toxicity. Moreover, by detecting the expression of CD31, N-cadherin, IL-6, IFN-γ, CD8, p16, p21, and p53 in tumor tissues, we found that GDNPs@ICG substantially reduced angiogenesis, inhibited metastasis, activated the anti-tumor immune response, and promoted cell senescence in breast tumor.

CONCLUSION

Our study demonstrated that the novel bio-nanoplatform GDNPs@ICG enhanced the photo-mediated therapeutic effect in breast tumor. GDNPs@ICG could be an alternative for precise and efficient anti-tumor phototherapy.

Photon-Driven Dye Induction Pyroptosis: An Emerging Anti-Tumor Immunotherapy Paradigm

Photoimmunotherapy represents a novel and promising modality in anti-tumor immunotherapy, offering new hope in the realm of cancer treatment due to its distinctive mechanism and substantial therapeutic efficacy. This innovative approach synergistically integrates photon technology with immunological principles, utilizing photon energy to activate the body's immune response. Photon-driven pyroptosis, a pivotal element of photoimmunotherapy, has significantly revitalized the advancement of this discipline. To support this critical progress, this minireview offers an exhaustive examination of the organic dyes presently employed for photon-driven pyroptosis, alongside an analysis of the prevailing challenges and opportunities in dye molecule design. It is our aspiration that this minireview will contribute to the acceleration of developments in photon-driven pyroptosis dye and the broader field of photoimmunotherapy.

Liposomal chlorin e6-mediated photodynamic therapy induces cell pyroptosis and promotes anti-tumor immune effects in breast cancer

Pyroptosis is a form of inflammatory cell death that has been demonstrated to trigger anti-tumor immune responses. Photodynamic therapy (PDT) is an innovative non-invasive treatment for tumors that effectively destroys tumor cells and boosts anti-tumor immune response. The ability of PDT to trigger pyroptosis and its mechanism of action are yet uncertain. In this study, we firstly verified that PDT effectively eliminates tumor cells. TEM and Western blot analysis demonstrated that tumor cells underwent pyroptosis following PDT therapy. Lipo-Ce6 mostly accumulates in the mitochondria of 4 T1 cells, and abundant ROS generated during PDT severely damage cell mitochondria, leading to the release of mitochondrial DNA, triggering the inflammasome caspase-1 signaling cascade, and ultimately causing cell pyroptosis, in addition NAC (a scavenger of ROS) and EB (a scavenger of mitochondrial DNA) can effectively prevent cell pyroptosis by PDT, which indicated the key role of ROS in PDT induced pyroptosis. Moreover, we also found PDT tiggered immunogenic cell death (ICD). Fourthermore, PDT can efficiently suppress tumor growth, trigger ICD and induce cell pyroptosis in mice. The introducing of immune checkpoint inhibitor BMS202 significantly boosts the tumor inhibition rate and promotes the infiltration of immune cells into the tumor. The body weight and HE. staining of normal organs primarily indicated the safety of this combined strategy. Our study demonstrated that PDT induced cell pyroptosis through mitochondrial oxidative damage and PDT induced pyroptosis effectively boost anti-cancer immunity, the combination of PDT and immune checkpoint inhibitor may be a promising clinical tumor treatment approaches.

Recent advances in nanoagents delivery system-based phototherapy for osteosarcoma treatment

Osteosarcoma (OS) is a prevalent and highly malignant bone tumor, characterized by its aggressive nature, invasiveness, and rapid progression, contributing to a high mortality rate, particularly among adolescents. Traditional treatment modalities, including surgical resection, radiotherapy, and chemotherapy, face significant challenges, especially in addressing chemotherapy resistance and managing postoperative recurrence and metastasis. Phototherapy (PT), encompassing photodynamic therapy (PDT) and photothermal therapy (PTT), offers unique advantages such as low toxicity, minimal drug resistance, selective destruction, and temporal control, making it a promising approach for the clinical treatment of various malignant tumors. Constructing multifunctional delivery systems presents an opportunity to effectively combine tumor PDT, PTT, and chemotherapy, creating a synergistic anti-tumor effect. This review aims to consolidate the progress in the application of novel delivery system-mediated phototherapy in osteosarcoma. By summarizing advancements in this field, the objective is to propose a rational combination therapy involving targeted delivery systems and phototherapy for tumors, thereby expanding treatment options and enhancing the prognosis for osteosarcoma patients. In conclusion, the integration of innovative delivery systems with phototherapy represents a promising avenue in osteosarcoma treatment, offering a comprehensive approach to overcome challenges associated with conventional treatments and improve patient outcomes.

Precision Cancer Therapy Enabled Anti-Epidermal Growth Factor Receptor-Conjugated Manganese Core Phthalocyanine Bismuth Nanocomposite for Dual Imaging-Guided Breast Cancer Treatment

Cancer remains a formidable global health challenge, demanding the exploration of innovative treatment modalities with minimized side effects. One promising avenue involves the synergistic integration of targeted photothermal/photodynamic therapy (PTT/PDT), utilizing specially designed functional nanomaterials for precise cancer diagnosis and treatment. This study introduces a composite biomaterial, anti-epidermal growth factor receptor-conjugated manganese core phthalocyanine bismuth (anti-EGFR-MPB), synthesized for precise cancer imaging and treatment. The biomaterial, synthesized via a solvothermal process, effectively treats and images breast cancer in mouse models. Its biomimetic design targets cancer cells precisely, with dual imaging for real-time monitoring. The biomimetic design of the composite enables precise targeting of cancer cells, whereas the dual imaging allows for real-time visualization and monitoring of the treatment. In vivo examinations confirm substantial damage to tumor tissues with no recurrence following 808-nm laser irradiation. The composite shows strong fluorescence/photoacoustic imaging (PAI) contrast, aiding malignancy detection. Biological assays and histological analyses confirmed the efficacy of the nanocomposite in inducing apoptosis in cancer cells. The integrated targeted dual image-guided phototherapy offered by this composite substantially enhances the precision and efficacy of cancer therapy, achieving an impressive photothermal efficiency of ~33.8%. Our findings demonstrate the utility of the anti-EGFR-MPB nanocomposite for both in vitro and in vivo photoacoustic image-guided PTT and PDT. The optimal treatment strategy for triple-negative breast cancer is found to be the use of 250 μg/ml of nanocomposite irradiated with 1.0 W/cm2 808-nm laser for 7 min.

Polymeric nanocarrier via metabolism regulation mediates immunogenic cell death with spatiotemporal orchestration for cancer immunotherapy

The limited efficacy of cancer immunotherapy occurs due to the lack of spatiotemporal orchestration of adaptive immune response stimulation and immunosuppressive tumor microenvironment modulation. Herein, we report a nanoplatform fabricated using a pH-sensitive triblock copolymer synthesized by reversible addition-fragmentation chain transfer polymerization enabling in situ tumor vaccination and tumor-associated macrophages (TAMs) polarization. The nanocarrier itself can induce melanoma immunogenic cell death (ICD) via tertiary amines and thioethers concentrating on mitochondria to regulate metabolism in triggering endoplasmic reticulum stress and upregulating gasdermin D for pyroptosis as well as some features of ferroptosis and apoptosis. After the addition of ligand cyclic arginine-glycine-aspartic acid (cRGD) and mannose, the mixed nanocarrier with immune adjuvant resiquimod encapsulation can target B16F10 cells for in situ tumor vaccination and TAMs for M1 phenotype polarization. In vivo studies indicate that the mixed targeting nanoplatform elicits tumor ICD, dendritic cell maturation, TAM polarization, and cytotoxic T lymphocyte infiltration and inhibits melanoma volume growth. In combination with immune checkpoint blockade, the survival time of mice is markedly prolonged. This study provides a strategy for utilizing immunoactive materials in the innate and adaptive immune responses to augment cancer therapy.

Advanced Strategies for Strengthening the Immune Activation Effect of Traditional Antitumor Therapies

The utilization of traditional therapies (TTS), such as chemotherapy, reactive oxygen species-based therapy, and thermotherapy, to induce immunogenic cell death (ICD) in tumor cells has emerged as a promising strategy for the activation of the antitumor immune response. However, the limited effectiveness of most TTS in inducing the ICD effect of tumors hinders their applications in combination with immunotherapy. To address this challenge, various intelligent strategies have been proposed to strengthen the immune activation effect of these TTS, and then achieve synergistic antitumor efficacy with immunotherapy. These strategies primarily focus on augmenting the tumor ICD effect or facilitating the antigen (released by the ICD tumor cells) presentation process during TTS, and they are systematically summarized in this review. Finally, the existing bottlenecks and prospects of TTS in the application of tumor immune regulation are also discussed.

A Pyroptosis-Inducing Arsenic(III) Nanomicelle Platform for Synergistic Cancer Immunotherapy

Immunogenic cell death (ICD) could activate anti-tumor immune responses, which is highly attractive for improving cancer treatment effectiveness. Here, this work reports a multifunctional arsenic(III) allosteric inhibitor Mech02, which induces excessive accumulation of 1O2 through sensitized biocatalytic reactions, leading to cell pyroptosis and amplified ICD effect. After Mech02 is converted to Mech03, it could actualize stronger binding effects on the allosteric pocket of pyruvate kinase M2, further interfering with the anaerobic glycolysis pathway of tumors. The enhanced DNA damage triggered by Mech02 and the pyroptosis of cancer stem cells provide assurance for complete tumor clearance. In vivo experiments prove nanomicelle Mech02-HA NPs is able to activate immune memory effects and raise the persistence of anti-tumor immunity. In summary, this study for the first time to introduce the arsenic(III) pharmacophore as an enhanced ICD effect initiator into nitrogen mustard, providing insights for the development of efficient multimodal tumor therapy agents.

Dihydroartemisinin-driven TOM70 inhibition leads to mitochondrial destabilization to induce pyroptosis against lung cancer

Enhancement of malignant cell immunogenicity to relieve immunosuppression of lung cancer microenvironment is essential in lung cancer treatment. In previous study, we have demonstrated that dihydroartemisinin (DHA), a kind of phytopharmaceutical, is effective in inhibiting lung cancer cells and boosting their immunogenicity, while the initial target of DHA's intracellular action is poorly understood. The present in-depth analysis aims to reveal the influence of DHA on the highly expressed TOM70 in the mitochondrial membrane of lung cancer. The affinity of DHA and TOM70 was analyzed by microscale thermophoresis (MST), pronase stability, and thermal stability. The functions and underlying mechanism were investigated using western blots, qRT-PCR, flow cytometry, and rescue experiments. TOM70 inhibition resulted in mtDNA damage and translocation to the cytoplasm from mitochondria due to the disruption of mitochondrial homeostasis. Further ex and in vivo findings also showed that the cGAS/STING/NLRP3 signaling pathway was activated by mtDNA and thereby malignant cells underwent pyroptosis, leading to enhanced immunogenicity of lung cancer cells in the presence of DHA. Nevertheless, DHA-induced mtDNA translocation and cGAS/STING/NLRP3 mobilization were synchronously attenuated when TOM70 was replenished. Finally, DHA was demonstrated to possess potent anti-lung cancer efficacy in vitro and in vivo. Taken together, these data confirm that TOM70 is an important target for DHA to disturb mitochondria homeostasis, which further activates STING and arouses pyroptosis to strengthen immunogenicity against lung cancer thereupon. The present study provides vital clues for phytomedicine-mediated anti-tumor therapy.

Activating Iterative Revolutions of the Cancer-Immunity Cycle in Hypoxic Tumors with a Smart Nano-Regulator

The activation of sequential events in the cancer-immunity cycle (CIC) is crucial for achieving effective antitumor immunity. However, formidable challenges, such as innate and adaptive immune resistance, along with the off-target adverse effects of nonselective immunomodulators, persist. In this study, a tumor-selective nano-regulator named PNBJQ has been presented, focusing on targeting two nonredundant immune nodes: inducing immunogenic cancer cell death and abrogating immune resistance to fully activate endogenous tumor immunity. PNBJQ is obtained by encapsulating the immunomodulating agent JQ1 within a self-assembling system formed by linking a Type-I photosensitizer to polyethylene glycol through a hypoxia-sensitive azo bond. Benefiting from the Type-I photosensitive mechanism, PNBJQ triggers the immunogenic cell death of hypoxic tumors under near-infrared (NIR) light irradiation. This process resolves innate immune resistance by stimulating sufficient cytotoxic T-lymphocytes. Simultaneously, PNBJQ smartly responds to the hypoxic tumor microenvironment for precise drug delivery, adeptly addressing adaptive immune resistance by using JQ1 to downregulate programmed death ligand 1 (PD-L1) and sustaining the response of cytotoxic T lymphocytes. The activatable synergic photoimmunotherapy promotes an immune-promoting tumor microenvironment by activating an iterative revolution of the CIC, which remarkably eradicates established hypoxic tumors and suppresses distal lesions under low light dose irradiation.

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.

Synergistically Augmenting Cancer Immunotherapy by Physical Manipulation of Pyroptosis Induction

Pyroptosis is a newly recognized type of programmed cell death mediated by the gasdermin family and caspase. It is characterized by the formation of inflammasomes and the following inflammatory responses. Recent studies have elucidated the value of pyroptosis induction in cancer treatment. The inflammatory cytokines produced during pyroptosis can trigger immune responses to suppress malignancy. Physical approaches for cancer treatment, including radiotherapy, light-based techniques (photodynamic and photothermal therapy), ultrasound-based techniques (sonodynamic therapy and focused ultrasound), and electricity-based techniques (irreversible electroporation and radiofrequency ablation), are effective in clinical application. Recent studies have reported that pyroptosis is involved in the treatment process of physical approaches. Manipulating pyroptosis using physical approaches can be utilized in combating cancer, according to recent studies. Pyroptosis-triggered immunotherapy can be combined with the original anti-tumor methods to achieve a synergistic therapy and improve the therapeutic effect. Studies have also revealed that enhancing pyroptosis may increase the sensitivity of cancer cells to some physical approaches. Herein, we present a comprehensive review of the literature focusing on the associations between pyroptosis and various physical approaches for cancer and its underlying mechanisms. We also discussed the role of pyroptosis-triggered immunotherapy in the treatment process of physical manipulation.

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 STING elicits GSDMD-dependent pyroptosis and boosts anti-tumor immunity in renal cell carcinoma

While Stimulator-of-interferon genes (STING) is an innate immune adapter cruicial for sensing cytosolic DNA and modulating immune microenvironment, its tumor-promoting role in tumor survival and immune evasion remains largely unknown. Here we reported that renal cancer cells are exceptionally dependent on STING for survival and evading immunosurveillance via suppressing ER stress-mediated pyroptosis. We found that STING is significantly amplified and upregulated in clear cell renal cell carcinoma (ccRCC), and its elevated expression is associated with worse clinical outcomes. Mechanically, STING depletion in RCC cells specifically triggers activation of the PERK/eIF2α/ATF4/CHOP pathway and activates cleavage of Caspase-8, thereby inducing GSDMD-mediated pyroptosis, which is independent of the innate immune pathway of STING. Moreover, animal study revealed that STING depletion promoted infiltration of CD4+ and CD8+ T cells, consequently boosting robust antitumor immunity via pyroptosis-induced inflammation. From the perspective of targeted therapy, we found that Compound SP23, a PROTAC STING degrader, demonstrated comparable efficacy to STING depletion both in vitro and in vivo for treatment of ccRCC. These findings collectively unveiled an unforeseen function of STING in regulating GSDMD-dependent pyroptosis, thus regulating immune response in RCC. Consequently, pharmacological degradation of STING by SP23 may become an attractive strategy for treatment of advanced RCC.

A PROTAC Augmenter for Photo-Driven Pyroptosis in Breast Cancer

Proteolysis targeting chimera (PROTAC) has recently emerged as a promising strategy for inducing post-translational knockdown of target proteins in disease treatment. The degradation of bromodomain-containing protein 4 (BRD4), an essential nuclear protein for gene transcription, induced by PROTAC is proposed as an epigenetic approach to treat breast cancer. However, the poor membrane permeability and indiscriminate distribution of PROTAC in vivo results in low bioavailability, limiting its development and application. Herein, a nano "targeting chimera" (abbreviated as L@NBMZ) consisting of BRD4-PROTAC combined with a photosensitizer, to serve as the first augmenter for photo-driven pyroptosis in breast cancer, is developed. With excellent BRD4 degradation ability, high biosafety, and biocompatibility, L@NBMZ blocks gene transcription by degrading BRD4 through proteasomes in vivo, and surprisingly, induces the cleavage of caspase-3. This type of caspase-3 cleavage is synergistically amplified by light irradiation in the presence of photosensitizers, leading to efficient photo-driven pyroptosis. Both in vitro and in vivo outcomes demonstrate the remarkable anti-cancer efficacy of this augmenter, which significantly inhibits the lung metastasis of breast cancer in vivo. Thus, the photo-PROTAC "targeting chimera" augmenter construction strategy may pave a new way for expanding PROTAC applications within anti-cancer paradigms.

Recent Advances in Reprogramming Strategy of Tumor Microenvironment for Rejuvenating Photosensitizers-Mediated Photodynamic Therapy

Photodynamic therapy (PDT) has recently been considered a potential tumor therapy due to its time-space specificity and non-invasive advantages. PDT can not only directly kill tumor cells by using cytotoxic reactive oxygen species but also induce an anti-tumor immune response by causing immunogenic cell death of tumor cells. Although it exhibits a promising prospect in treating tumors, there are still many problems to be solved in its practical application. Tumor hypoxia and immunosuppressive microenvironment seriously affect the efficacy of PDT. The hypoxic and immunosuppressive microenvironment is mainly due to the abnormal vascular matrix around the tumor, its abnormal metabolism, and the influence of various immunosuppressive-related cells and their expressed molecules. Thus, reprogramming the tumor microenvironment (TME) is of great significance for rejuvenating PDT. This article reviews the latest strategies for rejuvenating PDT, from regulating tumor vascular matrix, interfering with tumor cell metabolism, and reprogramming immunosuppressive related cells and factors to reverse tumor hypoxia and immunosuppressive microenvironment. These strategies provide valuable information for a better understanding of the significance of TME in PDT and also guide the development of the next-generation multifunctional nanoplatforms for PDT.

A lipid/PLGA nanocomplex to reshape tumor immune microenvironment for colon cancer therapy

Immune checkpoint blockade therapy provides a new strategy for tumor treatment; however, the insufficient infiltration of cytotoxic T cells and immunosuppression in tumor microenvironment lead to unsatisfied effects. Herein, we reported a lipid/PLGA nanocomplex (RDCM) co-loaded with the photosensitizer Ce6 and the indoleamine 2,3-dioxygenase (IDO) inhibitor 1MT to improve immunotherapy of colon cancer. Arginine-glycine-aspartic acid (RGD) as the targeting moiety was conjugated on 1,2-distearoyl-snglycero-3-phosphoethanolamine lipid via polyethylene glycol (PEG), and programmed cell death-ligand 1 (PD-L1) peptide inhibitor DPPA (sequence: CPLGVRGK-GGG-d(NYSKPTDRQYHF)) was immobilized on the terminal group of PEG via matrix metalloproteinase 2 sensitive peptide linker. The Ce6 and 1MT were encapsulated in PLGA nanoparticles. The drug loaded nanoparticles were composited with RGD and DPPA modified lipid and lecithin to form lipid/PLGA nanocomplexes. When the nanocomplexes were delivered to tumor, DPPA was released by the cleavage of a matrix metalloproteinase 2-sensitive peptide linker for PD-L1 binding. RGD facilitated the cellular internalization of nanocomplexes via avβ3 integrin. Strong immunogenic cell death was induced by 1O2 generated from Ce6 irradiation under 660 nm laser. 1MT inhibited the activity of IDO and reduced the inhibition of cytotoxic T cells caused by kynurenine accumulation in the tumor microenvironment. The RDCM facilitated the maturation of dendritic cells, inhibited the activity of IDO, and markedly recruited the proportion of tumor-infiltrating cytotoxic T cells in CT26 tumor-bearing mice, triggering a robust immunological memory effect, thus effectively preventing tumor metastasis. The results indicated that the RDCM with dual IDO and PD-L1 inhibition effects is a promising platform for targeted photoimmunotherapy of colon cancer.

Immunogenic cell stress and death in the treatment of cancer

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

Engineering materials for pyroptosis induction in cancer treatment

Cancer remains a significant global health concern, necessitating the development of innovative therapeutic strategies. This research paper aims to investigate the role of pyroptosis induction in cancer treatment. Pyroptosis, a form of programmed cell death characterized by the release of pro-inflammatory cytokines and the formation of plasma membrane pores, has gained significant attention as a potential target for cancer therapy. The objective of this study is to provide a comprehensive overview of the current understanding of pyroptosis and its role in cancer treatment. The paper discusses the concept of pyroptosis and its relationship with other forms of cell death, such as apoptosis and necroptosis. It explores the role of pyroptosis in immune activation and its potential for combination therapy. The study also reviews the use of natural, biological, chemical, and multifunctional composite materials for pyroptosis induction in cancer cells. The molecular mechanisms underlying pyroptosis induction by these materials are discussed, along with their advantages and challenges in cancer treatment. The findings of this study highlight the potential of pyroptosis induction as a novel therapeutic strategy in cancer treatment and provide insights into the different materials and mechanisms involved in pyroptosis induction.

Precise Photodynamic Therapy by Midkine Nanobody-Engineered Nanoparticles Remodels the Microenvironment of Pancreatic Ductal Adenocarcinoma and Potentiates the Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is notorious for its resistance against chemotherapy and immunotherapy due to its dense desmoplastic and immunosuppressive tumor microenvironment (TME). Traditional photodynamic therapy (PDT) was also less effective for PDAC owing to poor selectivity, insufficient penetration, and accumulation of photosensitizers in tumor sites. Here, we designed a light-responsive novel nanoplatform targeting the TME of PDAC through tumor-specific midkine nanobodies (Nbs), which could efficiently deliver semiconducting polymeric nanoparticles (NPs) to the TME of PDAC and locally produce abundant reactive oxygen species (ROS) for precise photoimmunotherapy. The synthesized nanocomposite can not only achieve multimodal imaging of PDAC tumors (fluorescence and photoacoustic imaging) but also lead to apoptosis and immunogenic cell death of tumor cells via ROS under light excitation, ultimately preventing tumor progression and remodeling the immunosuppressive TME with increased infiltration of T lymphocytes. Combined with a PD-1 checkpoint blockade, the targeted PDT platform showed the best antitumor performance and markedly extended mice survival. Conclusively, this work integrating Nbs with photodynamic NPs provides a novel strategy to target formidable PDAC to achieve tumor suppression and activate antitumor immunity, creating possibilities for boosting efficacy of immunotherapy for PDAC tumors through the combination with precise local PDT.

Near-Infrared Light-Triggered Thermoresponsive Pyroptosis System for Synergistic Tumor Immunotherapy

Pyroptosis, as an inflammatory cell death, has been widely applied in tumor therapy, but its systemic adverse reactions caused by nonspecific activation still seriously hinder its application. Herein, a near-infrared (NIR) light-triggered thermoresponsive pyroptosis strategy is designed for on-demand initiation of pyroptosis and synergistic tumor immunotherapy. Specifically, glucose oxidase (GOx) loaded and heat-sensitive material p(OEOMA-co-MEMA) (PCM) modified mesoporous Pt nanoparticles (abbreviated as PCM Pt/GOx) are prepared as the mild-temperature triggered pyroptosis inducer. Pt nanoparticles can not only serve as nanozyme with catalase-like activity to promote GOx catalytic reaction, but also act as photothermal agent to achieve mild-temperature photothermal therapy (PTT) and thermoresponsive GOx release on-demand under the irradiation of NIR light, thereby activating and promoting pyroptosis. In vitro and in vivo experiments prove that NIR light-triggered thermoresponsive pyroptosis system exhibits excellent antitumor immunity activity as well as significantly inhibits tumor growth. The precise control of pyroptosis by NIR light as well as pyroptosis cooperated with mild-temperature PTT for synergistically attenuated tumor immunotherapy are reported for the first time. This work provides a new method to initiate pyroptosis on demand, which is of great significance for spatiotemporally controllable pyroptosis and immunotherapy.

Recent strategies for evoking immunogenic Pyroptosis in antitumor immunotherapy

Pyroptosis is a specific type of programmed cell death (PCD) characterized by distinct morphological changes, including cell swelling, membrane blebbing, DNA fragmentation, and eventual cell lysis. Pyroptosis is closely associated with human-related diseases, such as inflammation and malignancies. Since the initial observation of pyroptosis in Shigella flexneri-infected macrophages more than 20 years ago, various pyroptosis-inducing agents, including ions, small molecules, and biological nanomaterials, have been developed for tumor treatment. Given that pyroptosis can activate the body's robust immune response against tumor and promote the formation of the body's long-term immune memory in tumor treatment, its status as a type of immunogenic cell death is self-evident. Therefore, pyroptosis should be used as a powerful anti-tumor strategy. However, there still is a lack of a comprehensive summary of the most recent advances in pyroptosis-based cancer therapy. Therefore, it is vital to fill this gap and inspire future drug design to better induce tumor cells to undergo pyroptosis to achieve advanced anti-tumor effects. In this review, we summarize in detail the most recent advances in triggering tumor cell immunogenic pyroptosis for adequate tumor clearance based on various treatment modalities, and highlight material design and therapeutic advantages. Besides, we also provide an outlook on the prospects of this emerging field in the next development.

Cell Death Pathway Regulation by Functional Nanomedicines for Robust Antitumor Immunity

Cancer immunotherapy has become a mainstream cancer treatment over traditional therapeutic modes. Cancer cells can undergo programmed cell death including ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis which are find to have intrinsic relationships with host antitumor immune response. However, direct use of cell death inducers or regulators may bring about severe side effects that can also be rapidly excreted and degraded with low therapeutic efficacy. Nanomaterials are able to carry them for long circulation time, high tumor accumulation and controlled release to achieve satisfactory therapeutic effect. Nowadays, a large number of studies have focused on nanomedicines-based strategies through modulating cell death modalities to potentiate antitumor immunity. Herein, immune cell types and their function are first summarized, and state-of-the-art research progresses in nanomedicines mediated cell death pathways (e.g., ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis) with immune response provocation are highlighted. Subsequently, the conclusion and outlook of potential research focus are discussed.

Modified 5-aminolevulinic acid photodynamic therapy induces cutaneous squamous cell carcinoma cell pyroptosis via the JNK signaling pathway

Modified 5-aminolevulinic acid photodynamic therapy (M-PDT) is a novel therapeutic modality for cutaneous squamous cell carcinoma (cSCC) that is reported to be effective and well tolerated. However, the mechanisms underlying its antitumor effects are not fully understood. In this research, we investigated the effects of M-PDT on pyroptosis, a form of programmed cell death characterized by cell swelling, ruptures of cell membrane, and inflammatory cytokine release, in two human cSCC cell lines, SCL-1 and HSC-5. We found that M-PDT triggered pyroptosis in a dose-dependent manner, as evidenced by increased lactate dehydrogenase release, propidium iodide staining, and expression of pyroptosis-related proteins, such as NLR family pyrin domain containing 3 (NLRP3), N-terminal of gasdermin D (N-GSDMD), cleaved caspase-1, and mature interleukin 1 beta (IL-1B) in both cell lines. This process was inhibited by treatment with MCC950, an NLRP3-specific inhibitor, suggesting the involvement of the NLRP3 inflammasome in M-PDT-induced pyroptosis. We also demonstrated that M-PDT activated c-Jun N-terminal kinase (JNK) signaling, which is required for pyroptosis induction, as treatment with SP600125, a JNK inhibitor, suppressed the expression of pyroptosis-related proteins after M-PDT. JNK activation enhanced M-PDT-induced pyroptosis, highlighting the significance of the JNK pathway in M-PDT. Moreover, M-PDT increased intracellular reactive oxygen species (ROS) levels, which are responsible for JNK activation and pyroptosis induction. In summary, our results revealed that M-PDT triggers pyroptosis through ROS-mediated JNK activation and subsequent NLRP3 inflammasome activation in cSCC cells, providing a better understanding of the molecular mechanism of M-PDT and promoting its clinical application.

Boosting immunogenic cell death via hollow MnO2-based multiple stimuli-responsive drug delivery systems for improved cancer immunotherapy

Cancer treatment by inducing tumor cell immunogenic cell death (ICD) is critical for tumor therapy. However, ICD activation by single pathway is often limited in practical application due to its low efficiency. In addition, the low pH and anoxic microenvironments in solid tumors greatly limit the effective activation of ICD. Herein, hollow manganese dioxide (H-MnO2) nanomaterials were selected to load both Mitoxantrone (MTZ) and Chlorin e6 (Ce6) due to its hollow structure and ability to release drugs in the acidic environments. Thus, the synergy of photodynamic therapy (PDT), photothermal therapy (PTT) and chemotherapy can induce the process of immunogenic cell death, stimulate the maturation of dendritic cells (DCs), and activate the immune response to kill tumor cells dramatically. Efficient immunotherapeutic effects were obtained when MnO2-C/M-HA was given intravenously to 4T1 tumor-bearing BALB/c mice with 660 nm near-infrared laser irradiation. This study overcame the limitations of monotherapy and provided a multifunctional platform for tumor immunotherapy.

Tumor Microenvironment-Activated Nanocomposite for Self-Amplifying Chemodynamic/Starvation Therapy Enhanced IDO-Blockade Tumor Immunotherapy

Disrupting intracellular redox homeostasis combined with immune checkpoint blockade therapy is considered as an effective way to accelerate tumor cell death. However, suppressed tumor immune microenvironment and lower cargo delivery restrict the efficiency of tumor therapy. In this study, a multifunctional tumor microenvironment (TME)-responsive nanocomposite is constructed using manganese tetroxide (Mn3 O4 )-decorated disulfide-bond-incorporated dendritic mesoporous organosilica nanoparticles (DMONs) to co-deliver indoleamine 2,3-dioxygenase (IDO) inhibitor Epacadostat (IDOi) and glucose oxidase (GOx) following modification with polyethylene glycol. Owing to the responsiveness of Mn3 O4 -decorated DMONs to the mildly acidic and glutathione (GSH) overexpressed TME, the nanocomposite can rapidly decompose and release inner contents, thus substantially improving the cargo release ability. Mn3 O4 can effectively catalyze hydrogen peroxide (H2 O2 ) decomposition to generate oxygen, enhance the ability of GOx to consume glucose to produce H2 O2 , and further promote the generation of hydroxyl radicals (•OH) by Mn2+ . Furthermore, Mn2+ -mediated GSH depletion and the production of •OH can disrupt intracellular redox homeostasis, contributing to immunogenic cell death. Simultaneously, IDOi can inhibit IDO to reverse inhibited immune response. The results show that self-amplifying chemodynamic/starvation therapy combined IDO-blockade immunotherapy synergistically inhibits tumor growth and metastasis in vivo.

Sequence-Responsive Multifunctional Supramolecular Nanomicelles Act on the Regression of TNBC and Its Lung Metastasis via Synergic Pyroptosis-Mediated Immune Activation

Design of effective nanodrugs to modulate the immunosuppression of tumor microenvironment is a desirable approach to boost the clinical tumor-therapeutic effect. Supramolecular nanomicelles PolyMN-TO-8, which are constructed by self-assembling supramolecular host MTX-MPEG2000, guest NPX-2S, and TO-8 through hydrophobic forces, have excellent stability and responsiveness to carboxylesterase and glutathione in turn. In vivo studies validate that PolyMN-TO-8 enable to trigger pyroptosis-mediated immunogenic cell death under laser, avoiding the occurrence of immune dysregulation simultaneously. This therapeutic mode strengthens dendritic cells' maturation and accelerates the infiltration of CD8+ T cells into tumors through moderate activation of pro-inflammatory factors with elimination of immune-escape, ultimately making the tumor inhibition rate as high as 87.44% via synergistic functions of photodynamic therapy, photothermal therapy, chemotherapy, etc. The loss of immune-escape quickens the infiltration of CD8+ T cells into lungs, and further eschews the generation of tumor nodules in it. Chemotherapy, the release of interferon-γ, and immune memory effect also strengthen the defense against metastasis. The generation of O2 catalyzed by PolyMN-TO-8 under laser is indispensable for tumor metastasis inhibition undoubtedly.

Nanomedicine-mediated regulated cell death in cancer immunotherapy

Immunotherapy has attracted widespread attention in cancer treatment and has achieved considerable success in the clinical treatment of some tumors, but it has a low response rate in most tumors. To achieve sufficient activation of the immune response, significant efforts using nanotechnology have been made to enhance cancer immune response. In recent years, the induction of various regulated cell death (RCD) has emerged as a potential antitumor immuno-strategy, including processes related to apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis. In particular, damage-associated molecular patterns (DAMPs) released from the damaged membrane of dying cells act as in situ adjuvants to trigger antigen-specific immune responses by the exposure of an increased antigenicity. Thus, RCD-based immunotherapy offers a new approach for enhancing cancer treatment efficacy. Furthermore, incorporation with multimodal auxiliary therapies in cell death-based immunotherapy can trigger stronger immune responses, resulting in more efficient therapeutic outcome. This review discusses different RCD modalities and summarizes recent nanotechnology-mediated RCDs in cancer immunotherapy.

Gasdermin D: A Potential New Auxiliary Pan-Biomarker for the Detection and Diagnosis of Diseases

Pyroptosis is a form of programmed cell death mediated by gasdermins, particularly gasdermin D (GSDMD), which is widely expressed in tissues throughout the body. GSDMD belongs to the gasdermin family, which is expressed in a variety of cell types including epithelial cells and immune cells. It is involved in the regulation of anti-inflammatory responses, leading to its differential expression in a wide range of diseases. In this review, we provide an overview of the current understanding of the major activation mechanisms and effector pathways of GSDMD. Subsequently, we examine the importance and role of GSDMD in different diseases, highlighting its potential as a pan-biomarker. We specifically focus on the biological characteristics of GSDMD in several diseases and its promising role in diagnosis, early detection, and differential diagnosis. Furthermore, we discuss the application of GSDMD in predicting prognosis and monitoring treatment efficacy in cancer. This review proposes a new strategy to guide therapeutic decision-making and suggests potential directions for further research into GSDMD.

Golgi Apparatus-Targeted Photodynamic Therapy for Enhancing Tumor Immunogenicity by Eliciting NLRP3 Protein-Dependent Pyroptosis

Innate and adaptive immunity is important for initiating and maintaining immune function. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome serves as a checkpoint in innate and adaptive immunity, promoting the secretion of pro-inflammatory cytokines and gasdermin D-mediated pyroptosis. As a highly inflammatory form of cell death distinct from apoptosis, pyroptosis can trigger immunogenic cell death and promote systemic immune responses in solid tumors. Previous studies proposed that NLRP3 was activated by translocation to the mitochondria. However, a recent authoritative study has challenged this model and proved that the Golgi apparatus might be a prerequisite for the activation of NLRP3. In this study, we first developed a Golgi apparatus-targeted photodynamic strategy to induce the activation of NLRP3 by precisely locating organelles. We found that Golgi apparatus-targeted photodynamic therapy could significantly upregulate NLRP3 expression to promote the subsequent release of intracellular proinflammatory contents such as IL-1β or IL-18, creating an inflammatory storm to enhance innate immunity. Moreover, this acute NLRP3 upregulation also activated its downstream classical caspase-1-dependent pyroptosis to enhance tumor immunogenicity, triggering adaptive immunity. Pyroptosis eventually led to immunogenic cell death, promoted the maturation of dendritic cells, and effectively activated antitumor immunity and long-lived immune memory. Overall, this Golgi apparatus-targeted strategy provided molecular insights into the occurrence of immunogenic pyroptosis and offered a platform to remodel the tumor microenvironment.

Immuno-Nanozymes Mediated Synergistic Chemodynamic/Immuno-Therapy with Potentiated Anti-Tumor Efficacy

Nanozymes mediated chemodynamic therapy (CDT) is a newly developed therapeutic modality with high specificity. The efficacy of CDT, however, still confronts challenges from the immune inhibitory tumor microenvironment (TME). It is thus of great significance to synergize CDT with immunotherapeutic interventions. Herein, this work reports the design and preparation of CpG loaded, Cu2+ doped double layered hydroxides nanosheets (CpG/Cu-LDHs) as immuno-nanozymes to potentiate overall anti-tumor efficacy by synergizing CDT with immunogenic cell death (ICD)-activated local and systemic immune responses. Such cooperative CDT-immuno effect together with immunosuppressive TME remodeling capacity conferred by CpG/Cu-LDHs led to effective suppression of both treated primary tumor and untreated distant tumor on a mouse tumor model. Thereby, synergizing CDT with ICD-driven, in situ vaccine-like immunotherapy by immuno-nanozymes provides a novel and generalized paradigm for devising highly efficient and specific anti-tumor strategy without the use of external stimulations.

Enhancing tumor immunotherapy via photodynamic therapy with a cascade reaction of reactive oxygen species and sustaining nutrient supply

Photo-immunotherapy is a promising strategy for the treatment of malignancies; however, its efficacy is often limited by the low tumor immunogenicity and immunosuppressive tumor microenvironment (TME). TME is typically deficient in L-arginine (L-Arg), which negatively impacts T cell survival and function. To address this issue, we developed a novel drug delivery system based on the multi-vesicular liposomes (MVLs) loaded with photosensitizer indocyanine green (ICG) and L-Arg (R), named R-ICG@MVLs. Under near-infrared (NIR) light irradiation, the PDT-mediated cascade reaction of reactive oxygen species (ROS) could oxidize a portion of L-Arg to generate NO, thereby inducing immunogenic tumor cell death (ITCD) and stimulating anti-tumor immune responses, including antigen-presenting cells (APCs) recruitment and T cells activation. Subsequently, R-ICG@MVLs continued to release L-Arg, which improved the immunosuppressive TME, providing nutritional support for the tumor-infiltrating T cells and thus enhancing their anti-tumor efficacy. Additionally, the photo-thermal effect of ICG could accelerate the membrane rearrangement of R-ICG@MVLs and produce multiple drug-loaded nanovesicles, thus enabling the NIR-controlled accelerated drug release. The formation of drug-loaded nanovesicles led to deeper penetration and widened the range of ICD and TME improvement, achieving a "shrapnel effect". In conclusion, our strategy realized the dual effects of immune activation and nutrition support, which might provide a clinically applicable reference for tumor immunotherapy.

Combination of ferroptosis and pyroptosis dual induction by triptolide nano-MOFs for immunotherapy of Melanoma

Immunotherapy has good potential to eradicate tumors in the long term. However, due to the low immunogenicity of tumor cells, current cancer immunotherapies are not effective. To address this limitation, we constructed a BSA-FA functionalized iron-containing metal-organic framework (TPL@TFBF) that triggers a potent systemic anti-tumor immune response by inducing ferroptosis and pyroptosis in tumor cells and releasing large quantities of damage-associated molecular patterns (DAMPs) to induce immunogenicity, and showing excellent efficacy against melanoma lung metastases in vivo. This nanoplatform forms a metal-organic framework through the coordination between tannic acid (TA) and Fe3+ and is then loaded with triptolide (TPL), which is coated with FA-modified BSA. The nanoparticles target melanoma cells by FA modification, releasing TPL, Fe3+ and TA. Fe3+ is reduced to Fe2+ by TA, triggering the Fenton reaction and resulting in ROS production. Moreover, TPL increases the production of intracellular ROS by inhibiting the expression of nuclear factor erythroid-2 related factor (Nrf2). Such simultaneous amplification of intracellular ROS induces the cells to undergo ferroptosis and pyroptosis, releasing large amounts of DAMPs, which stimulate antigen presentation of dendritic cells (DCs) and the proliferation of cytotoxic T lymphocytes (CD4+/CD8 + T cells) to inhibit tumor and lung metastasis. In addition, combining nanoparticle treatment with immune checkpoint blockade (ICB) further inhibits melanoma growth. This work provides a new strategy for tumor immunotherapy based on various combinations of cell death mechanisms.

Amplifying cancer treatment: advances in tumor immunotherapy and nanoparticle-based hyperthermia

In the quest for cancer treatment modalities with greater effectiveness, the combination of tumor immunotherapy and nanoparticle-based hyperthermia has emerged as a promising frontier. The present article provides a comprehensive review of recent advances and cutting-edge research in this burgeoning field and examines how these two treatment strategies can be effectively integrated. Tumor immunotherapy, which harnesses the immune system to recognize and attack cancer cells, has shown considerable promise. Concurrently, nanoparticle-based hyperthermia, which utilizes nanotechnology to promote selective cell death by raising the temperature of tumor cells, has emerged as an innovative therapeutic approach. While both strategies have individually shown potential, combination of the two modalities may amplify anti-tumor responses, with improved outcomes and reduced side effects. Key studies illustrating the synergistic effects of these two approaches are highlighted, and current challenges and future prospects in the field are discussed. As we stand on the precipice of a new era in cancer treatment, this review underscores the importance of continued research and collaboration in bringing these innovative treatments from the bench to the bedside.

A S-substituted Nile Blue-derived bifunctional near-infrared fluorescent probe for in vivo carboxylesterase imaging-guided photodynamic therapy of hepatocellular carcinoma

The development of theranostic probes that integrate both diagnostic and therapeutic functions still remains an intractable challenge in precise cancer treatment. Herein, a novel bifunctional near-infrared (NIR) fluorescent probe (CEP1) for carboxylesterase (CE) imaging and photodynamic therapy (PDT) of hepatocellular carcinoma (HCC) has been firstly developed and successfully applied in vitro and in vivo. The probe was constructed by introducing carbamate as both the recognition unit and the fluorescence quenching unit into the fluorophore S-substituted Nile Blue (ENBS) via a self-eliminating spacer with substituted chloride. It can be activated by CE and hydrolyzed into fluorescent ENBS, which recover fluorescence at about 700 nm, and can generate superoxide radical anions under NIR irradiation. Additionally, the probe could effectively distinguish tumor cells from normal cells by CE imaging of live cells. Furthermore, it could achieve CE imaging in vivo and significantly inhibits tumor growth by imaging-guided PDT. Therefore, this study offers a promising and attractive platform for activatable imaging-guided PDT of HCC.

Metal-Based Photosensitizers as Inducers of Regulated Cell Death Mechanisms

Over the last few decades, various forms of regulated cell death (RCD) have been discovered and were found to improve cancer treatment. Although there are several reviews on RCD induced by photodynamic therapy (PDT), a comprehensive summary covering metal-based photosensitizers (PSs) as RCD inducers has not yet been presented. In this review, we systematically summarize the works on metal-based PSs that induce different types of RCD, including ferroptosis, immunogenic cell death (ICD), and pyroptosis. The characteristics and mechanisms of each RCD are explained. At the end of each section, a summary of the reported commonalities between different metal-based PSs inducing the same RCD is emphasized, and future perspectives on metal-based PSs inducing novel forms of RCD are discussed at the end of the review. Considering the essential roles of metal-based PSs and RCD in cancer therapy, we hope that this review will provide the stage for future advances in metal-based PSs as RCD inducers.

Interrelation between Programmed Cell Death and Immunogenic Cell Death: Take Antitumor Nanodrug as an Example

Programmed cell death (PCD, mainly including apoptosis, necrosis, ferroptosis, pyroptosis, and autophagy) and immunogenic cell death (ICD), as important cell death mechanisms, are widely reported in cancer therapy, and understanding the relationship between the two is significant for clinical tumor treatments. Considering that vast nanodrugs are developed to induce tumor PCD and ICD simultaneously, in this review, the interrelationship between PCD and ICD is described using nanomedicines as examples. First, an overview of PCD patterns and focus on the morphological differences and interconnections among them are provided. Then the interrelationship between apoptosis and ICD in terms of endoplasmic reticulum stress is described by introducing various cancer treatments and the recent developments of nanomedicines with inducible immunogenicity. Next, the crosstalk between non-apoptotic (including necrosis, ferroptosis, pyroptosis, and autophagy) signaling pathways and ICD is introduced and their relationship through various nanomedicines as examples is further illustrated. Finally, the relationship between PCD and ICD and its application prospects in the development of new ICD nanomaterials are summarized. This review is believed to deepen the understanding of the relationship between PCD and ICD, extend the biomedical applications of various nanodrugs, and promote the progress of clinical tumor therapy.

Precision Delivery of Dual Immune Inhibitors Loaded Nanomodulator to Reverse Immune Suppression for Combinational Photothermal-Immunotherapy

Although photothermal therapy (PTT) can noninvasively kill tumor cells and exert synergistic immunological effects, the immune responses are usually harmed due to the lack of cytotoxic T cells (CTLs) pre-infiltration and co-existing of intricate immunosuppressive tumor microenvironment (TME), including the programmed cell death ligand 1 (PD-L1)/cluster of differentiation 47 (CD47)/regulatory T cells (Tregs)/M2-macrophages overexpression. Indoleamine 2, 3-dioxygenase inhibitor (NLG919) or bromodomain extra-terminal inhibitor (OTX015) holds great promise to reprogram suppressive TME through different pathways, but their collaborative application remains a formidable challenge because of the poor water solubility and low tumor targeting. To address this challenge, a desirable nanomodulator based on dual immune inhibitors loaded mesoporous polydopamine nanoparticles is designed. This nanomodulator exhibits excellent biocompatibility and water solubility, PTT, and bimodal magnetic resonance/photoacoustic imaging abilities. Owing to enhanced permeability and retention effect and tumor acidic pH-responsiveness, both inhibitors are precisely delivered and locally released at tumor sites. Such a nanomodulator significantly reverses the immune suppression of PD-L1/CD47/Tregs, promotes the activation of CTLs, regulates M2-macrophages polarization, and further boosts combined therapeutic efficacy, inducing a strong immunological memory. Taken together, the nanomodulator provides a practical approach for combinational photothermal-immunotherapy, which may be further broadened to other "immune cold" tumors.

Recent Organic Photosensitizer Designs for Evoking Proinflammatory Regulated Cell Death in Antitumor Immunotherapy

In the past decades, immunotherapy has achieved a series of clinical successes in the field of cancer. However, existing therapeutic options usually show a low immune response to solid tumors caused by immunosuppressive "cold" tumor microenvironment (TME). Several types of proinflammatory regulated cell death (RCD), mainly including ferroptosis and pyroptosis, have been studied recently, which can provide proinflammatory signals and immunogenicity necessary for remodeling TME and activating an antitumor immune response. A variety of chemotherapeutic drugs are proven to be effective in the proinflammatory RCD induction of tumor cells, but several adverse effects and intrinsic drug resistance usually occur in the therapeutic process, greatly hindering their further clinical application. The emerging organic photosensitizer (PS)-based materials open new possibilities to effectively activate proinflammatory RCD through precise spatiotemporal regulation of intracellular reactive oxygen species-associated signaling pathways, which can overcome many challenges encountered in current proinflammatory RCD-mediated immunotherapy. In this review, the recent design strategies of PS probes are detailly summarized and their potential advantages for tumor-specific proinflammatory RCD induction are discussed. Moreover, the representative examples in cancer immunotherapy are highlighted and future perspectives in this emerging field are proposed.

Immuno-photodynamic Therapy (IPDT): Organic Photosensitizers and Their Application in Cancer Ablation

Photosensitizer-based photodynamic therapy (PDT) has been considered as a promising modality for fighting diverse types of cancers. PDT directly inhibits local tumors by a minimally invasive strategy, but it seems to be incapable of achieving complete eradication and fails to prevent metastasis and recurrence. Recently, increasing events proved that PDT was associated with immunotherapy by triggering immunogenic cell death (ICD). Upon a specific wavelength of light irradiation, the photosensitizers will turn the surrounding oxygen molecules into cytotoxic reactive oxygen species (ROS) for killing the cancer cells. Simultaneously, the dying tumor cells release tumor-associated antigens, which could improve immunogenicity to activate immune cells. However, the progressively enhanced immunity is typically limited by the intrinsic immunosuppressive tumor microenvironment (TME). To overcome this obstacle, immuno-photodynamic therapy (IPDT) has come to be one of the most beneficial strategies, which takes advantage of PDT to stimulate the immune response and unite immunotherapy for inducing immune-OFF tumors to immune-ON ones, to achieve systemic immune response and prevent cancer recurrence. In this Perspective, we provide a review of recent advances in organic photosensitizer-based IPDT. The general process of immune responses triggered by photosensitizers (PSs) and how to enhance the antitumor immune pathway by modifying the chemical structure or conjugating with a targeting component was discussed. In addition, future perspectives and challenges associated with IPDT strategies are also discussed. We hope this Perspective could inspire more innovative ideas and provide executable strategies for future developments in the war against cancer.

Photon-Controlled Pyroptosis Activation (PhotoPyro): An Emerging Trigger for Antitumor Immune Response

Pyroptosis refers to the process of gasdermin-mediated lytic programmed cell death (PCD) characterized by the release of pro-inflammatory cytokines. Our knowledge of pyroptosis has expanded beyond the cellular level and now includes extracellular responses. In recent years, pyroptosis has attracted considerable attention due to its potential to induce host immunity. For instance, at the 2022 International Medicinal Chemistry of Natural Active Ligand Metal-Based Drugs (MCNALMD) conference, numerous researchers demonstrated an interest in photon-controlled pyroptosis activation ("PhotoPyro"), an emerging pyroptosis-engineered approach for activating systemic immunity via photoirradiation. Given this enthusiasm, we share in this Perspective our views on this emerging area and expound on how and why "PhotoPyro" could trigger antitumor immunity (i.e., turning so-called "cold" tumors "hot"). In doing so, we have tried to highlight cutting-edge breakthroughs in PhotoPyro while suggesting areas for future contributions. By providing insights into the current state of the art and serving as a resource for individuals interested in working in this area, it is hoped that this Perspective will set the stage for PhotoPyro to evolve into a broadly applicable cancer treatment strategy.

Pyroptosis-Mediated Synergistic Photodynamic and Photothermal Immunotherapy Enabled by a Tumor-Membrane-Targeted Photosensitive Dimer

Overcoming the resistance to apoptosis and immunosuppression of tumor cells is a significant challenge in augmenting the effect of cancer immunotherapy. Pyroptosis, a lytic programmed cell-death pathway unlike apoptosis, is considered a type of immunogenic cell death (ICD) that can intensify the ICD process in tumor cells, releasing dramatically increased tumor-associated antigens and damage-associated molecular patterns to promote cancer immunotherapy. Herein, a tumor cell membrane-targeted aggregation-induced emission photosensitive dimer is found to be able to achieve highly efficient ICD under the synergistic effect of photodynamic and photothermal therapy. The photosensitive dimer can efficiently produce type-I reactive oxygen species (ROS) by photodynamic therapy in hypoxic tumor tissue, leading to pyroptosis by direct cell membrane damage, which is further reinforced by its photothermal effect. Furthermore, the enhanced ICD effect based on the dimer can completely eliminate the primary tumor on the seventh day of treatment and can also boost systemic antitumor immunity by generating immune memory, which is demonstrated by the superior antitumor therapeutic effects on both solid tumors and metastatic tumors when healing 4T1 tumor mouse models with poor immunogenicity.

Photothermal "nano-dot" reactivate "immune-hot" for tumor treatment via reprogramming cancer cells metabolism

Cancer immunotherapy, despite its enormous application prospect, is trapped in the abnormal lactic acid metabolism of tumor cells that usually causes an immunosuppressive tumor microenvironment (ITM). Inducing immunogenic cell death (ICD) not only sensitizes cancer cells to carcer immunity, but also leads to a great increase in tumor-specific antigens. It improves tumor condition from "immune-cold" to "immune-hot". Herein, a near-infrared photothermal agent NR840 was developed and encapsulated into tumor-targeted polymer DSPE-PEG-cRGD and carried lactate oxidase (LOX) by electrostatic interaction, forming self-assembling "nano-dot" PLNR840 with high loading capacity for synergistic antitumor photo-immunotherapy. In this strategy, PLNR840 was swallowed by cancer cells, then dye NR840 was excited at 808 nm to generate heat inducing tumor cell necrosis, which further caused ICD. LOX could serve as a catalyst, reducing lactic acid efflux via regulation of cell metabolism. More importantly, the consumption of intratumoral lactic acid could substantially reverse ITM, including promoting the polarization of tumor-associated macrophages from M2 to M1 type, inhibiting the viability of regulatory T cells for sensitizing photothermal therapy (PTT). After the combination of αPD-L1 (programmed cell death protein ligand 1), PLNR840 restored CD8⁺ T-cell activity that thoroughly cleaned the pulmonary metastasis of breast cancer in 4T1 mouse model and cured hepatocellular carcinoma in Hepa1-6 mouse model. This study provided an effective PTT strategy to boost "immune-hot" and reprogrammed tumor metabolism for antitumor immunotherapy.