Nanoscale coordination polymers induce immunogenic cell death by amplifying radiation therapy mediated oxidative stress

Self-assembly of paclitaxel derivative and fructose as a potent inducer of immunogenic cell death to enhance cancer immunotherapy

Immunotherapy shows promise for tumor control but is limited by low response rates. Paclitaxel (PTX) induces immunogenic cell death (ICD), yet conventional delivery systems face challenges like low drug loading and insufficient intracellular accumulation, reducing ICD efficacy. Small-molecule self-assembled PTX nanoparticles offer a promising solution due to high drug loading and dose delivery. In this study, PTX was conjugated with phenylboronic acid (PBA) to form the derivative PTX-PBA, which spontaneously self-assembled with fructose into nanoparticles (PTX-PBA-Fru NPs). These nanoparticles exhibited a uniform size of 107.8 ± 2.9 nm, a PDI of 0.064 ± 0.042, and a zeta potential of -12.2 ± 0.9 mV, with spherical morphology. In 4T1 tumor-bearing mice, PTX-PBA-Fru NPs significantly enhanced tumor inhibition (p < 0.001) and increased body weight (p < 0.05). No allergic reactions in healthy Balb/c mice and the maximum tolerated intravenous dose reached 200 mg/kg, underscoring its favorable safety profile of PTX-PBA-Fru NPs. The ICD effects induced by PTX-PBA-Fru NPs, when combined with the immunomodulator resiquimod (R848), elicited a robust anti-tumor immune response. This combination therapy effectively remodeled the immunosuppressive tumor microenvironment and achieved a 37.5 % tumor eradication rate. Moreover, it established long-term immune memory, providing protection against tumor re-challenge. This novel PTX formulation demonstrates strong anti-tumor effects, safety, and clinical potential in combination with R848-based immunotherapy.

Targeted Delivery of SmacN7 Peptide Induces Immunogenic Cell Death in Cervical Cancer Treatment

Cervical cancer is a common tumor in women and one of the common causes of cancer death in women. Due to the aggressive and non-specific nature of traditional chemotherapy, there is a growing need for new treatment modalities. Currently, tumor immunotherapy is increasingly garnering attention as a disruptive treatment approach. Therefore, we constructed CCTP-SmacN7, a delivery system capable of releasing active molecules in the tumor microenvironment. CCTP-SmacN7 can not only inhibit tumor proliferation and migration, but also induce tumors to produce large amounts of reactive oxygen species. The production of reactive oxygen species can activate tumors to release or expose damage-associated molecular patterns, promote DC cell maturation, and ultimately activate T cells. Here, we present an innovative targeted treatment approach for cervical cancer. While inducing tumor immunogenic cell death, this program can also improve the tumor microenvironment and initiate the tumor immune cycle.

Bacteria-based biohybrids for remodeling adenosine-mediated immunosuppression to boost radiotherapy-triggered antitumor immune response

Radiotherapy (RT) can trigger immunogenic cell death (ICD) in tumor cells and release adenosine triphosphate (ATP) to activate antitumor immunity. However, the formation of immunosuppressive adenosine (ADO) mediated by ectonucleotidases including CD39 and CD73, can exacerbate the immunosuppressive effects. Herein, a radiosensitizer-based metal-organic framework (MOF) composed of bismuth (Bi) and ellagic acid (EA) was synthesized in situ on the surface of Escherichia coli Nissle 1917 (EcN) to serve as a carrier for the CD39 inhibitor sodium polyoxotungstate (POM-1). This therapeutic platform, acting as a radiosensitizer, significantly enhances cytotoxicity against tumor cells while effectively inducing ICD and releasing high concentrations of ATP. Subsequently, the released POM-1 increases the levels of pro-inflammatory extracellular ATP while preventing tumor immunosuppression caused by the accumulation of ADO. Additionally, as a natural immune adjuvant, EcN further promotes the maturation of dendritic cells (DCs) and the infiltration of cytotoxic T lymphocytes (CTLs). As a result, such treatment initiates the destruction of established tumor growth and induces strong abscopal effects, leading to a significant inhibition of tumor metastases. This strategy presents a bacterial-based biohybrid system that facilitates RT-induced ICD while simultaneously limiting the degradation of ATP into ADO, thereby achieving sustained anti-tumor immunity.

Metallized hollow-COF nanobowls with dual-mode ROS generation for cancer sonodynamic therapy

Sonodynamic therapy (SDT) has emerged as an encouraging route in tumor treatment, due to its exceptional tissue penetration depth and favorable safety profile. Nevertheless, the clinical translation of conventional organic sonosensitizers is hindered by intrinsic limitations, including pronounced hydrophobicity, insufficient chemical stability, and low reactive oxygen species (ROS) production. In contrast, hollow covalent organic frameworks (HCOFs) exhibit exceptional cargo-loading capabilities, structural robustness, and biocompatibility, positioning them as ideal nanoplatforms for advanced therapeutic applications. Herein, we engineered a bowl-shaped HCOF architecture designed to amplify ultrasonic cavitation effects. This nanostructure was subsequently functionalized with the sonosensitizer (Hemin) and subjected to strategic metallization via metal ion incorporation, culminating in the development of a high-efficiency antitumor nanosystem (FeHHCA). FeHHCA can achieve dual-mode ROS generation, namely, sonodynamic synergistically generating 1O2 and being specifically activated by a tumor microenvironment (TME) to generate ˙OH through a Fenton-like reaction, achieving an 78.7% tumor inhibition rate in vivo. These findings offer innovative approaches and strategies for the design of hollow COFs and offer great potential for the application of SDT in cancer treatment.

Phagocytosis-Activating Nanocomplex Orchestrates Macrophage-Mediated Cancer Immunotherapy

The phagocytosis of macrophages to tumor cells represents an alluring strategy for cancer immunotherapy; however, its effectiveness is largely hindered by the detrimental upregulation of anti-phagocytic signals and insufficient expression of pro-phagocytic signals of tumor cells. Here, a pro-phagocytic polymer-based nanocomplex is designed to promote the macrophage engulfment of tumor cells through concurrent modulation of both the "eat me" and "don't eat me" signals. The nanocomplex MNCCD47i-CALRt is formed by complexing a synthetic PAMAM derivative (G4P-C7A) that is capable of intrinsically inducing the exposure of calreticulin (CALR, a crucial pro-phagocytic protein) and a small inference RNA that can inhibit the expression of CD47 (a primary anti-phagocytic protein). MNCCD47i-CALRt can significantly delay tumor growth and prolong the survival of tumor-bearing mice with negligible hematopoietic toxicity in multiple murine colorectal cancer models. Furthermore, the pro-phagocytic capacity of MNCCD47i-CALRt is validated in the patient-derived tumor organoid model. Collectively, the phagocytosis-promoting nanocomplex provides a simple and potent strategy for boosting macrophage-mediated cancer immunotherapy.

A Metformin-Based Multifunctional Nanoplatform as a DNA Damage Amplifier for Maximized Radio-Immunotherapy to Overcome Radiotherapy Resistance

Radiotherapy (RT) has been highlighted to be an effective strategy for antitumor immunity activation by causing direct DNA damages, but it generally suffers from low response rates due to the compromised cytosolic DNA (cDNA) recognition by cyclic GMP-AMP synthase (cGAS). Simultaneous DNA repair and clearance system regulation for enhanced cDNA accumulation is a useful approach to improve immune response rates, which remains seldom reported to our knowledge. Here, we report the construction of a metformin (MET)-based multifunctional nanocomplex, CS-MET/siTREX1 (CSMT), consisting of biguanide-decorated CS (CS-MET) as the vector and 3'-5' DNA exonuclease TREX1 siRNA (siTREX1) as the therapeutic gene for RT-induced antitumor immunity enhancement by amplifying the initial DNA damage signals. The uniqueness of this study is the development of CSMT as a specific DNA damage amplifier to promote cDNA accumulation for maximizing radio-immunotherapy and circumventing RT resistance. Specifically, the CSMT nanocomplexes show not only enhanced gene transfection efficiency by MET modification but also synergistic therapeutic effects including MET's inhibition on DNA repair and siTREX1's attenuation on cDNA clearance, which leads to the greatest inhibitory effect in a Hepa1-6 proximal/distal tumor model with a high tumor growth inhibition (TGI) value of 99.1% for the primary tumor and significantly compromised distal tumor growth by inducing immunogenic cell death (ICD), promoting tumor-associated neutrophil (TAN) polarization, and stimulating tumor-specific memory T-cell generation. Overall, the CSMT nanocomplexes developed herein hold great translatable promises for overcoming RT resistance in clinics.

Nanomaterials-driven in situ vaccination: a novel frontier in tumor immunotherapy

In situ vaccination (ISV) has emerged as a promising strategy in cancer immunotherapy, offering a targeted approach that uses the tumor microenvironment (TME) to stimulate an immune response directly at the tumor site. This method minimizes systemic exposure while maintaining therapeutic efficacy and enhancing safety. Recent advances in nanotechnology have enabled new approaches to ISV by utilizing nanomaterials with unique properties, including enhanced permeability, retention, and controlled drug release. ISV employing nanomaterials can induce immunogenic cell death and reverse the immunosuppressive and hypoxic TME, thereby converting a "cold" tumor into a "hot" tumor and facilitating a more robust immune response. This review examines the mechanisms through which nanomaterials-based ISV enhances anti-tumor immunity, summarizes clinical applications of these strategies, and evaluates its capacity to serve as a neoadjuvant therapy for eliminating micrometastases in early-stage cancer patients. Challenges associated with the clinical translation of nanomaterials-based ISV, including nanomaterial metabolism, optimization of treatment protocols, and integration with other therapies such as radiotherapy, chemotherapy, and photothermal therapy, are also discussed. Advances in nanotechnology and immunotherapy continue to expand the possible applications of ISV, potentially leading to improved outcomes across a broad range of cancer types.

Self-assembling chemodrug fiber-hydrogel for transarterial chemoembolization and radiotherapy-enhanced antitumor immunity

Hydrogel, as a promising embolic material for hepatocellular carcinoma (HCC), may fully embolize both major vessels and peripheral microvessels. A self-assembling hydrogel composed of chemotherapeutic drugs offers significant clinical benefits without carrier introduction. Herein, we developed a sustained drug-releasing complex hydrogel (RKT@gel), which was fabricated by the self-assembly of raltitrexed chemotherapeutic drugs (R@gel), along with the incorporation of kaempferol and tantalum nanoparticles (Ta NPs). Kaempferol enhances the mechanical strength of R@gel and inhibits hypoxia-induced angiogenesis post-embolization, improving embolization effectiveness. In addition to enabling X-ray-guided transarterial chemoembolization (TACE), Ta NPs enhance radiation sensitivity. These synergistic effects of RKT@gel not only significantly induce immunogenic cell death, thereby enhancing the activation of dendritic cells, but also activate major histocompatibility complex class I (MHC-I)-mediated antitumor immune recognition and cytotoxicity. In vivo, RKT@gel achieves enhanced tumor deposition and sustained drug release, effectively suppressing tumor progression. Additionally, when combined with radiotherapy, RKT@gel achieves efficient antitumor immunoactivation. Overall, this versatile composite hydrogel not only achieves effective embolization therapy but also substantially triggers antitumor immune responses with good biocompatibility. This multifunctional design provides a TACE-based multidisciplinary strategy for HCC.

Bioactive mesoporous silica materials-assisted cancer immunotherapy

Immunotherapy is initially envisioned as a powerful approach to train immune cells within the tumor microenvironment (TME) and lymphoid tissues to elicit strong anti-tumor responses. However, clinical cancer immunotherapy still faces challenges, such as limited immunogenicity and insufficient immune response. Leveraging the advantages of mesoporous silica (MS) materials in controllable drug and immunomodulator release, recent efforts have focused on engineering MS with intrinsic immunoregulatory functions to promote robust, systemic, and safe anti-tumor responses. This review discusses advances in bioactive MS materials that address the challenges of immunotherapy. Beyond their role in on-demand delivery and drug release in response to the TME, we highlight the intrinsic functions of bioactive MS in orchestrating localized immune responses by inducing immunogenic cell death in tumor cells, modulating immune cell activity, and facilitating tumor-immune cell interactions. Additionally, we emphasize the advantages of bioactive MS in recruiting and activating immune cells within lymphoid tissues to initiate anti-tumor vaccination. The review also covers the challenges of MS-assisted immunotherapy, potential solutions, and future outlooks. With a deeper understanding of material-bio interactions, the rational design of MS with sophisticated bioactivities and controllable responsiveness holds great promise for enhancing the outcomes of personalized immunotherapy.

Implanted Microneedles Loaded with Sparfloxacin and Zinc-Manganese Sulfide Nanoparticles Activates Immunity for Postoperative Triple-Negative Breast Cancer to Prevent Recurrence and Metastasis

Recent investigations have underscored the significant role of manganese ions (Mn2+) in immunization, particularly through the activation of the cGAS-STING pathway, which enhances antitumor immune responses. However, the rapid metabolism of free Mn2+ following administration limits its effectiveness as an immune adjuvant. To address these challenges, microneedles (MNs) of hyaluronic acid containing Sparfloxacin (SP) and zinc-manganese sulfide (ZMS) are prepared for the postoperative in situ treatment of triple-negative breast cancer (TNBC) to prevent cancer recurrence and combat wound infection. ZMS/SP (ZS)-loaded MNs exhibit strong antimicrobial and antibiofilm properties that are crucial for preventing postoperative infections. Moreover, the generation of reactive oxygen species by these MNs disrupts the oxidative balance, effectively activating immunogenic cell death and facilitating the release of cytokines. ZS significantly suppressed tumor growth, reduced lung metastasis, and promoted wound healing. These effects are accompanied by notable increases in immune cell infiltration and activation, which is consistent with the gene sequencing results. Activation of the cGAS-STING pathway further improved antitumor immunity. These findings highlight the potential of ZS MNs as an effective and safe treatment that utilizes the immunostimulatory properties of Mn2+ to enhance local and systemic immune responses for the prevention of postoperative TNBC metastasis.

Nanoradiosentizers with X ray-actuatable supramolecular aptamer building units for programmable immunostimulatory T cell engagement

The insufficient activation and impaired effector functions of T cells in the immunosuppressive tumor microenvironment (TME) substantially reduces the immunostimulatory effects of radiotherapy. Herein, a multifunctional nanoradiosensitizer is established by integrating molecularly engineered aptamer precursors into cisplatin-loaded liposomes for enhancing radio-immunotherapy of solid tumors. Exposure to ionizing radiation (IR) following the nanoradiosensitizer treatment would induce pronounced immunogenic death (ICD) of tumor cells through cisplatin-mediated radiosensitization while also trigger the detachment of the aptamer precursors, which further self-assemble into PD-L1/PD-1-bispecific aptamer-based T cell engagers (CA) through the bridging effect of tumor-derived ATP to direct T cell binding onto tumor cells in the post-IR TME in a spatial-temporally programmable manner. The CA-mediated post-IR tumor-T cell engagement could override the immunosuppressive barriers in TME and enhance T cell-mediated recognition and elimination of tumor cells while minimizing systemic toxicities. Overall, this work offers an innovative approach to enhance the radio-immunotherapeutic efficacy in the clinics.

Cyclooxygenase-2/prostaglandin E2 inhibition remodulated photodynamic therapy-associated immunosuppression for enhanced cancer immunotherapy

Low immunogenicity and immunosuppressive tumor microenvironment (TME) are two pivotal factors restricting tumor immunotherapy. Photodynamic therapy (PDT) directly destroys cancer cells by producing reactive oxygen species (ROS), and enhances the immunogenicity of "cold" tumors by inducing immunogenic cell death (ICD), thereby promoting T cell development against tumors. However, PDT also deteriorates immunosuppression through overactivating the cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) pathway. To this end, biocompatible albumin nanoassemblies co-delivering IR780 and diclofenac are herein developed for enhanced therapy against triple-negative breast cancer. PDT-exacerbated PGE2 overexpression is effectively abolished by diclofenac-mediated COX-2 inhibition, which reprograms immunosuppressive TME via downregulating the infiltration of various immunosuppressive cells and their cytokine secretion to enhance effector T cell infiltration. Consequently, the enhanced antitumor immunity effectively inhibits tumor growth, prevents the recurrency and metastasis, and remarkably boosts the treatment efficacy of PD-L1 blockade. This study sets an intriguing example for overcoming the COX-2/PGE2 pathway-exacerbated immunosuppression alongside immune activation, thus enhancing synergistic cancer immunotherapy potentiated by various ROS-producing therapies (e.g., PDT and radiotherapy) and chemotherapy.

One-Dose Bioorthogonal Gadolinium Nanoprobes for Prolonged Radiosensitization of Tumor

Developing effective radiotherapy is impeded by tumor radioresistance, imprecise treatment, and the need for accurate imaging. Herein, a multifunctional gadolinium-based nanoprobe (GBD) is presented, integrating bioorthogonal click chemistry and theranostics to enhance tumor retention, magnetic resonance imaging (MRI) contrast, and radiosensitivity. GBD synthesis involved biomimetic mineralization of bovine serum albumin (BSA) with gadolinium ions to form nanoparticles (GB), followed by conjugation with dibenzocyclooctyne (DBCO). The optimized GBD exhibited an elevated longitudinal relaxivity (r1) of 25.54 mM-1 s-1, which represented a 6.7-fold enhancement compared to the clinical MRI contrast agent magnevist (Gd-DTPA, 3.81 mM-1 s-1). Notably, the application of bioorthogonal click chemistry enhanced the affinity and retention of GBD within tumor cells modified to express azide as an artificial receptor. This novel strategy enhanced tumor retention up to 16 days postinjection, outperforming DBCO-modified small molecule gadolinium (Gd-DBCO) with less than 1-day retention. Such prolonged retention facilitated continuous radiosensitization throughout the radiotherapy course, negating the need for multiple injections, and substantially boosted the effectiveness of radiotherapy. This study demonstrates the transformative potential of combining bioorthogonal click chemistry with nanotechnology in radiotherapy, offering a precise tumor targeting platform, real-time monitoring, and improved treatment outcomes.

NAT10 promotes radiotherapy resistance in non-small cell lung cancer by regulating KPNB1-mediated PD-L1 nuclear translocation

Radiotherapy (RT) resistance in non-small cell lung cancer (NSCLC) is a significant contributor to tumor recurrence. NAT10, an enzyme that catalyzes ac4C RNA modification, has an unclear role in RT resistance. This study aimed to explore the function of NAT10 in RT resistance in NSCLC. RT-resistant NSCLC cell lines (PC9R and A549R) were established through repeated irradiation. The impact of NAT10 on cellular immunity was evaluated by measuring immune cell populations, cytotoxicity levels, and markers of cell dysfunction. Results demonstrated elevated levels of ac4C and NAT10 in RT-resistant cells. Knockdown of NAT10 suppressed cell proliferation and enhanced immune function in PC9R and A549R cells by upregulating TNF-α and IFN-γ while downregulating PD-1 and TIM-3. Mechanistically, RT resistance in NSCLC was mediated by NAT10-dependent ac4C modification of KPNB1. Furthermore, KPNB1 facilitated PD-L1 nuclear translocation, promoting immune escape in RT-resistant NSCLC cells. Overexpression of KPNB1 enhanced cell proliferation but impaired immune function in RT-resistant NSCLC cells. In conclusion, this study demonstrates that NAT10 upregulates KPNB1 expression through ac4C modification, thereby promoting RT resistance in NSCLC via PD-L1 nuclear translocation. These findings reveal a novel mechanism underlying RT resistance in NSCLC.

Nucleic Acid Drugs in Radiotherapy

Radiotherapy remains a cornerstone of cancer treatment, using high-energy radiation to induce DNA damage in tumor cells, leading to cell death. However, its efficacy is often hindered by challenges such as radiation resistance and side effects. As a powerful class of functional molecules, nucleic acid drugs (NADs) present a promising solution to these limitations. Engineered to target key pathways like DNA repair and tumor hypoxia, NADs can enhance radiotherapy sensitivity. NADs can also serve as delivery vehicles for radiotherapy agents such as radionuclides, improving targeting accuracy and minimizing side effects. This review explores the role of NADs in optimizing radiotherapy, highlighting their mechanisms, clinical applications, and synergies with radiotherapy, ultimately offering a promising strategy for improving patient outcomes in cancer therapy.

Quasi Fe MIL-53 nanozyme inducing ferroptosis and immunogenic cell death for cancer immunotherapy

Nanozymes offer diverse therapeutic potentials for cancer treatment which is dependent on the development of nanomaterials. Quasi-metal-organic framework is a class of metal-organic framework-derived nanomaterials with a transition state from metal-organic frameworks towards metal oxide featuring porous structure and high activity. Herein an iron-based quasi-metal-organic framework nanozyme Q-MIL-53(Fe) is reported via a controlled deligandation strategy, exhibiting enhanced peroxidase-/catalase-mimic activity and glutathione depletion capacity, whose underlying mechanisms are studied via density functional theory calculations. Q-MIL-53(Fe) demonstrates biocompatibility and superior antitumor efficacy compared to pristine MIL-53(Fe). It can activate antitumor immune response by inducing ferroptosis and immunogenic cell death, promoting dendritic cell maturation and T lymphocytes infiltration. Furthermore, a combination of Q-MIL-53(Fe) and programmed cell death protein 1 antibody amplifies cancer immunotherapy. This study validates the antitumor activity of quasi-metal-organic frameworks and its immunotherapy induction potential. It would broaden the application of quasi-metal-organic frameworks and open avenues for developing antitumor nanozymes.

Engineering probiotic biohydrogen micro-factories to initiate reductive stress for boosting tumor vulnerability

Disruption of redox homeostasis profoundly affects cellular metabolism and activities. While oxidative stress is extensively studied in cancer therapies, research on reductive stress remains in its infancy. Molecular hydrogen (H2), a well-known antioxidant, holds significant potential to induce reductive stress due to its strong antioxidative properties, making it a promising candidate for cancer therapy. However, it remains a major challenge to develop a sustainable H2 delivery system in vivo. Herein, we designed a micro-factory by engineering a gel-based microcapsule that encapsulates Enterobacter aerogenes, a.k.a. probiotic biohydrogen microcapsules (PBMCs), enabling the sustained H2 generation within tumor microenvironment. Notably, PBMCs effectively suppressed the proliferation of eight tumor cell lines as well as drug-resistant cancer cells. The prolonged H2 release from PBMCs induced reductive stress, as evidenced by a significant increase in the GSH/GSSG ratio in 4T1 cells. Moreover, PBMCs displayed significant antitumor effects in breast, melanoma and liver cancer models. The inhibition of PI3K-AKT pathway and the activation of MAPK pathway were identified as key mechanisms responsible for inducing tumor cell cycle arrest and apoptosis. The PBMCs also exhibited synergistic effects in combination with chemotherapeutics, resulting in robust inhibitions of preinvasive carcinoma growth and commonly associated pulmonary metastasis. Overall, our study introduces an innovative strategy to manipulate reductive stress in the tumor microenvironment through in situ H2 generation, thereby enhancing tumor vulnerability.

Tumor microenvironment-activated polypeptide nanoparticles for oncolytic immunotherapy

Cationic oncolytic polypeptides have gained increasing attention owing to their ability to directly lyse cancer cells and activate potent antitumor immunity. However, the low tumor cell selectivity and inherent toxicity induced by positive charges of oncolytic polypeptides hinder their systemic application. Herein, a tumor microenvironment-responsive nanoparticle (DNP) is developed by the self-assembly of a cationic oncolytic polypeptide (PLP) with a pH-sensitive anionic polypeptide via electrostatic interactions. After the formation of DNP, the positive charges of PLP are shielded. DNPs can keep stable in physiological conditions (pH 7.4) but respond to acidic tumor microenvironment (pH 6.8) to release oncolytic PLP. As a result, DNPs evoke potent immunogenic cell death by disrupting cell membranes, damaging mitochondria and increasing intracellular levels of reactive oxygen species. In vivo results indicate that DNPs significantly improve the biocompatibility of PLP, and inhibit tumor growth, recurrence and metastasis by direct oncolysis and activation of antitumor immune responses. In summary, these results indicate that pH-sensitive DNPs represent a prospective strategy to improve the tumor selectivity and biosafety of cationic polymers for oncolytic immunotherapy.

Dual Porphyrin-Loaded Scintillating Nanoparticles Enhanced Photodynamic Therapy in Hypoxic Cancer Cells under X-ray Irradiation

Tumor hypoxia represents a major challenge to achieving successful therapy outcomes with photodynamic therapy (PDT). We hypothesized that systemic loading of dual porphyrins, protoporphyrin IX (PPIX) as a photosensitizer (PS) and hemin (Fe3+-PPIX) as an oxygen generator, onto Eu-doped NaYF4 scintillator (Sc), collectively terms as Eu-PPIX@Hemin, could enhance the activity of X-ray mediated PDT. Catalase-like property of hemin in the presence of H2O2 facilitated the production of oxygen molecules (3O2) in hypoxic cancer cells. The produced 3O2 reacts with nearby excited PPIX molecules (PPIX*) in the Sc-PS pairs to produce singlet oxygen (1O2), as cytotoxic reactive oxygen species (ROS) under X-ray irradiation. Eu-PPIX@Hemin nanoparticles (NPs) with a diameter of ~60 nm efficiently produced oxygen in the presence of H2O2, which its concentration in tumor cells is higher than that in normal cells. Eu-PPIX@Hemin generated similar amounts of ROS in hypoxic cultured cancer cells under low dose X-ray irradiation (0.5 Gy), compared to those in normoxic cancer cells. Notably, Eu-PPIX@Hemin exhibited similar cytotoxic effects in both hypoxic and normoxic cancer cells under X-ray irradiation. Overall, the mutual Sc-PS performance between PPIX and Eu was synergistically enhanced by hemin in Eu-PPIX@Hemin, which relieved hypoxia in the cancer cells under X-ray irradiation.

Cascaded immunotherapy with implantable dual-drug depots sequentially releasing STING agonists and apoptosis inducers

Non-nucleotide stimulators of interferon gene (STING) agonists hold promise as immunotherapeutic agents for postsurgical adjuvant treatment of tumors. However, their limited effect duration hampers therapeutic effectiveness, necessitating prolonged administration of multiple doses that heightens infection risk and impacts patient compliance. Here, we develop an implantable dual-drug depot in a sandwich-like configuration, with a non-nucleotide STING agonist (MSA-2) in the outer layers of 3D-printed scaffolds and an immunogenic apoptosis inducer (doxorubicin, DOX) in the inner layer of electrospun fibers. We discover that MSA-2 can elicit endoplasmic reticulum stress-mediated and general immunogenic apoptosis of cancer cells. The stimulations with tumor-associated antigens and damage-associated molecular patterns from cancer cells, along with proinflammatory factors secreted by matured dendritic cells and M1-polarized macrophages, can depolymerize intracellular microtubules guiding activated STING trafficking towards lysosomes for degradation. Collectively, the dual-drug depots can initiate a long-lasting cascaded immunotherapy and chemotherapy, suppressing postsurgical tumor recurrence and metastasis.

Advanced Polymeric Nanoparticles for Cancer Immunotherapy: Materials Engineering, Immunotherapeutic Mechanism and Clinical Translation

Cancer immunotherapy, which leverages immune system components to treat malignancies, has emerged as a cornerstone of contemporary therapeutic strategies. Yet, critical concerns about the efficacy and safety of cancer immunotherapies remain formidable. Nanotechnology, especially polymeric nanoparticles (PNPs), offers unparalleled flexibility in manipulation-from the chemical composition and physical properties to the precision control of nanoassemblies. PNPs provide an optimal platform to amplify the potency and minimize systematic toxicity in a broad spectrum of immunotherapeutic modalities. In this comprehensive review, the basics of polymer chemistry, and state-of-the-art designs of PNPs from a physicochemical standpoint for cancer immunotherapy, encompassing therapeutic cancer vaccines, in situ vaccination, adoptive T-cell therapies, tumor-infiltrating immune cell-targeted therapies, therapeutic antibodies, and cytokine therapies are delineated. Each immunotherapy necessitates distinctively tailored design strategies in polymeric nanoplatforms. The extensive applications of PNPs, and investigation of their mechanisms of action for enhanced efficacy are particularly focused on. The safety profiles of PNPs and clinical research progress are discussed. Additionally, forthcoming developments and emergent trends of polymeric nano-immunotherapeutics poised to transform cancer treatment paradigms into clinics are explored.

Ca2+- and cGAMP-Contained Semiconducting Polymer Nanomessengers for Radiodynamic-Activated Calcium Overload and Immunotherapy

Various second messengers exert some vital actions in biological systems, including cancer therapy, but the therapeutic efficacy is often need to be improved. A semiconducting polymer nanomessenger (TCa/SPN/a) consisting of two second messengers, calcium ion (Ca2+) and cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) for metastatic breast cancer therapy, is reported here. Such a TCa/SPN/a is constructed to exhibit X-ray response for the activatable delivery of mitochondria-targeting Ca compound and cGAMP as stimulator of interferon genes (STING) agonist. With X-ray irradiation, TCa/SPN/a could generate singlet oxygen (1O2) via radiodynamic effect for ablating solid tumors and improving the tumor immunogenicity by inducing immunogenic cell death (ICD). Furthermore, the released mitochondria-targeting Ca compounds show a high binging effect on mitochondria and cause reactive oxygen species (ROS) generation and mitochondria damage via calcium overload, while cGAMP boosts immunological effect through activating STING pathway. In this way, TCa/SPN/a enables a radiodynamic-activated calcium overload and immunotherapy to obviously inhibit the growths of bilateral tumors and also abolish tumor metastasis in metastatic breast cancer mouse models. This article should demonstrate the first smart dual-functional nanotherapeutic containing two second messengers for precise and specific cancer therapy.

Luminescent Lanthanide Infinite Coordination Polymers for Ratiometric Sensing Applications

Ratiometric lanthanide coordination polymers (Ln-CPs) are advanced materials that combine the unique optical properties of lanthanide ions (e.g., Eu3+, Tb3+, Ce3+) with the structural flexibility and tunability of coordination polymers. These materials are widely used in biological and chemical sensing, environmental monitoring, and medical diagnostics due to their narrow-band emission, long fluorescence lifetimes, and excellent resistance to photobleaching. This review focuses on the composition, sensing mechanisms, and applications of ratiometric Ln-CPs. The ratiometric fluorescence mechanism relies on two distinct emission bands, which provides a self-calibrating, reliable, and precise method for detection. The relative intensity ratio between these bands varies with the concentration of the target analyte, enabling real-time monitoring and minimizing environmental interference. This ratiometric approach is particularly suitable for detecting trace analytes and for use in complex environments where factors like background noise, temperature fluctuations, and light intensity variations may affect the results. Finally, we outline future research directions for improving the design and synthesis of ratiometric Ln-CPs, such as incorporating long-lifetime reference luminescent molecules, exploring near-infrared emission systems, and developing up-conversion or two-photon luminescent materials. Progress in these areas could significantly broaden the scope of ratiometric Ln-CP applications, especially in biosensing, environmental monitoring, and other advanced fields.

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.

Enhancing Ferroptosis-Mediated Radiosensitization via Synergistic Disulfidptosis Induction

Ferroptosis plays an important role in radiotherapy (RT), and the induction of ferroptosis can effectively sensitize radiotherapy. However, the therapeutic efficiency is always affected by ferroptosis resistance, especially SLC7A11 (Solute Carrier Family 7 Member 11)-cystine-cysteine-GSH (glutathione)-GPX4 (glutathione peroxidase 4) pathway-mediated resistance. In this study, tumor-microenvironment self-activated high-Z element-containing nanoferroptosis inducers, PEGylated Fe-Bi-SS metal-organic frameworks (FBSP MOFs), were developed to sensitize RT. Unexpectedly, ferroptosis-resistant SLC7A11 would be self-adaptively upregulated, leading to self-responsive ferroptosis resistance. Since the conversion from SLC7A11-transported cystine to cysteine is highly glucose-dependent, glucose oxidase (GOx) was incorporated in the MOFs, causing the depletion of NADPH (nicotinamide adenine dinucleotide phosphate) to terminate the conversion from cystine to cysteine, relieving the self-adaptive ferroptosis resistance. Excitingly, the accumulation of cystine would synergistically lead to disulfide stress and trigger disulfidptosis, making a new contribution to enhance therapeutic efficiency. Moreover, the hydrogen peroxide produced during glucose oxidation could also cascade-react with the Fenton reaction, therefore enhancing ferropotosis. Both in vitro and in vivo results suggested that therapeutic efficiency of ferroptosis-mediated radiosensitization could be enhanced benefiting from synergistic disulfidptosis induction, indicating that disulfidptosis might be an efficient strategy to relieve ferroptosis resistance and enhance RT efficiency.

Enhancing Chordoma Radiotherapy: Ta@PVP Nanoparticles as Potent Radiosensitizers

Surgical resection and high-dose radiotherapy constitute the standard therapeutic approaches for chordoma. However, the efficacy of radiotherapy is often compromised by the tumor microenvironment's hypoxic conditions, which confer radiation resistance, and by the potential damage to adjacent spinal cord and neural structures from elevated radiation doses. To address these challenges, we employed high biocompatible poly(vinylpyrrolidone)-modified tantalum nanoparticles (Ta@PVP NPs) as a potent radiosensitizer to augment the radiotherapy sensitivity of chordoma. Upon exposure to X-ray irradiation, Ta@PVP NPs demonstrated the capability to efficiently deposit X-ray radiation energy within the tumor microenvironment, subsequently generating reactive oxygen species (ROS) that induce oxidative stress in the tumor. Both in vitro and in vivo experiments revealed that Ta@PVP NPs significantly enhanced the cytotoxic effects of X-ray, thereby markedly inhibiting the proliferation of chordoma cells and impeding tumor growth. This study explored the radiosensitization potential of Ta@PVP NPs in the context of chordoma, highlighting the application of radiosensitizers as a promising strategy to augment the efficacy of chordoma radiotherapy.

Radiation Therapy Improves Survival in Patients with Distant Metastatic Head and Neck Squamous Cell Carcinoma: A Retrospective Study

BACKGROUND

The role of radiation therapy in patients with distant metastatic squamous cell carcinoma of the head and neck (mHNSCC) is unclear. In this study, we compare the differences in survival among mHNSCC patients treated with chemotherapy plus radiotherapy (RT) vs. chemotherapy alone.

MATERIALS AND METHODS

This study included patients with distant mHNSCC recruited from 2 cohorts: The Surveillance, Epidemiology, and End Results (SEER [N=885]) database and a Chinese single-institution registry in Sun Yat-sen University Cancer Center (SYSUCC [N=60]). The SEER cohort included 600 patients received RT plus chemotherapy and 285 patients received chemotherapy alone; in the SYSUCC cohort, 40 patients received RT plus chemotherapy and 20 patients received chemotherapy alone were recruited. The period of data collection for the SEER study was from January 2010 to December 2015, and that for SYSUCC was from January 2010 to December 2020. The study's primary outcome was overall survival (OS), with disease-specific survival (DSS) as a secondary outcome.

RESULTS

Of the 885 patients in the SEER cohort, the addition of RT to chemotherapy increased one-year OS from 46.6% to 56.0% compared with chemotherapy alone (P =0.009) and from 10.4% to 25.1% for three-year OS (P <0.001). Patients who received RT in addition to chemotherapy were also more likely to have better three-year DSS than those who received chemotherapy alone (28.9% vs. 14.0%, P<0.001). Similarly, in the SYSUCC cohort, patients who received chemotherapy plus RT had better three-year OS than chemotherapy alone (62.8% vs. 21.0%, P=0.003). The addition of RT to chemotherapy increased median OS among patients with mHNSCC from 10 months to 13 months in the SEER cohort and from 14 months to 29 months in the SYSUCC cohort.

CONCLUSION

Radiotherapy in addition to chemotherapy significantly improved OS and DSS in patients with mHNSCC.

Engineering Stimuli-Responsive Materials for Precision Medicine

Over the past decade, precision medicine has garnered increasing attention, making significant strides in discovering new therapeutic drugs and mechanisms, resulting in notable achievements in symptom alleviation, pain reduction, and extended survival rates. However, the limited target specificity of primary drugs and inter-individual differences have often necessitated high-dosage strategies, leading to challenges such as restricted deep tissue penetration rates and systemic side effects. Material science advancements present a promising avenue for these issues. By leveraging the distinct internal features of diseased regions and the application of specific external stimuli, responsive materials can be tailored to achieve targeted delivery, controllable release, and specific biochemical reactions. This review aims to highlight the latest advancements in stimuli-responsive materials and their potential in precision medicine. Initially, we introduce disease-related internal stimuli and capable external stimuli, elucidating the reaction principles of responsive functional groups. Subsequently, we provide a detailed analysis of representative pre-clinical achievements of stimuli responsive materials across various clinical applications, including enhancements in the treatment of cancers, injury diseases, inflammatory diseases, infection diseases, and high-throughput microfluidic biosensors. Finally, we discuss some clinical challenges, such as off-target effects, long-term impacts of nano-materials, potential ethical concerns, and offer insights into future perspectives of stimuli-responsive materials.

Curcumin and Metformin Infinite Coordination Polymer Nanoparticles for Combined Therapy of Diabetic Mice via Intraperitoneal Injections

Metformin (Met) is one of the most commonly prescribed first-line drugs for diabetes treatment. However, it has several issues, including low bioavailability, therapeutic platform, and side effects at high doses. In order to improve the therapeutic efficiency of Met, this study proposes a strategy of using Met and curcumin (Cur) to prepare Cur-Zn(II)-Met infinite coordination polymer nanoparticles (CM ICP NPs), and combining this with intraperitoneal injections, for the treatment of diabetic mice. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), nanoparticle analysis, cytotoxicity experiments, and mice experiments were used to investigate structure, properties, and application effects. The results showed that CM ICP NPs exhibit a high drug encapsulation rate (100%), good stability, and an absence of in vivo and in vitro toxicity. The blood glucose level of diabetic mice after treatment was reduced to 6.7 ± 0.65 mmol/L at the seventh week. In terms of therapeutic mechanism, it appears that Met and Cur can synergistically regulate blood glucose in mice from multiple paths. This study provides a promising method for the treatment of diabetes using Met and other drugs.

Zinc-based radioenhancers to activate tumor radioimmunotherapy by PD-L1 and cGAS-STING pathway

Radiotherapy and immunotherapy have already become the primary form of treatment for non-small-cell lung cancer (NSCLC), but are limited by high radiotherapy dose and low immune response rate. Herein, a multi-pronged strategy using a radio-immuno-enhancer (ZnO-Au@mSiO2) is developed by inducing tumor cells apoptosis and reprograming the immunosuppressive tumor microenvironment (TME). The radio-immuno-enhancer employed Au as a radiosensitizer, transition Zn ions as immune activators, which not only tremendously enhances the anti-proliferative activity of radiotherapy toward cancer cells, but also activates the immune response with multi-targets to let "exhausted" T cells "back to life" by triggering immunogenic cell death (ICD), immune checkpoint blockade (ICB) that target PD-1/PD-L1 and cGAS-STING under X-ray irradiation with a low dosage. The in vivo results demonstrate desirable antitumor and immunogenic effects of radio-immuno-enhancer-mediated immune activation by increasing the ratio of cytotoxic T cells (CTLs) and helper T cells. This work provides a feasible approach for future development of effective transition metal ion-activated radio-immunotherapeutic agents.

Synergistic SDT/cuproptosis therapy for liver hepatocellular carcinoma: enhanced antitumor efficacy and specific mechanisms

The efficacy of sonodynamic therapy (SDT), an emerging approach for tumor treatment, is hindered by the high levels of the antioxidant glutathione (GSH) in the tumor microenvironment (TME). In this study, we constructed nanobubbles loaded with the sonosensitizer HMME and the tumor-targeting peptide RGD (HMME-RGD@C3F8 NBs) for synergistic SDT/cuproptosis therapy of liver hepatocellular carcinoma (LIHC) in combination with Elesclomol-Cu as cuproptosis inducers. Endogenous GSH is consumed by Cu2+ to modulate the complex TME, thereby amplifying oxidative stress and further improving SDT performance. Additionally, intracellular Cu2+ overload can induce cuproptosis, which is further amplified by SDT, to initiate irreversible protein toxicity. The specific mechanism of synergistic SDT/cuproptosis therapy in LIHC was investigated by RNA sequencing analysis. The synergistic SDT/cuproptosis therapy reprogrammed the TME to improve the efficacy of immune checkpoint inhibitor-based immunotherapy. Furthermore, a risk-scoring model was created and displayed significant promise in the prognosis of LIHC.

Nanoscale Metal-Organic Frameworks and Nanoscale Coordination Polymers: From Synthesis to Cancer Therapy and Biomedical Imaging

Recently, there has been significant interest in nanoscale metal-organic frameworks (NMOFs) characterized by ordered crystal structures and nanoscale coordination polymers (NCPs) featuring amorphous structures. These structures arise from the coordination interactions between inorganic metal ions or clusters and organic ligands. Their advantages, such as the ability to tailor composition and structure, efficiently encapsulate diverse therapeutic or imaging agents within porous frameworks, inherent biodegradability, and surface functionalization capability, position them as promising carriers in the biomedical fields. This review provides an overview of the synthesis and surface modification strategies employed for NMOFs and NCPs, along with their applications in cancer treatment and biological imaging. Finally, future directions and challenges associated with the utilization of NMOFs and NCPs in cancer treatment and diagnosis are also discussed.

Nanotechnology-Based Strategies for Safe and Effective Immunotherapy

Cancer immunotherapy using immune checkpoint blockades has emerged as a promising therapeutic approach. However, immunotherapy faces challenges such as low response rates in solid tumors, necessitating strategies to remodel the immune-suppressive tumor microenvironment (TME) into an immune-activated state. One of the primary approaches to achieve this transformation is through the induction of immunogenic cell death (ICD). Herein, we discussed strategies to maximize ICD induction using nanoparticles. In particular, this review highlighted various studies integrating chemotherapy, radiation therapy (RT), photodynamic therapy (PDT), and photothermal therapy (PTT) with nanoparticle-based immunotherapy. The research covered in this review aims to provide valuable insights for future studies on nanoparticle-assisted immunotherapy.

A cuproptosis nanocapsule for cancer radiotherapy

Residual tumours that persist after radiotherapy often develop acquired radiation resistance, increasing the risk of recurrence and metastasis while providing obstacles to re-irradiation. Using samples from patients and experimental mice, we discovered that FDX1 and LIAS, key regulators of cuproptosis, were up-regulated in residual tumours following radiotherapy, conferring the increased sensitivity to cuproptosis. Therefore, we proposed a novel radiosensitization strategy focused on cuproptosis, using a copper-containing nanocapsule-like polyoxometalate as a paradigm. In an initial demonstration, we showed that the nanocapsule released copper ions in a controlled manner upon exposure to ionizing radiation. Furthermore, radiation-triggered cuproptosis overcame acquired radiation resistance even at clinically relevant radiation doses and activated a robust abscopal effect, with a 40% cure rate in both radioresistant and re-irradiation tumour models. Collectively, targeting cuproptosis is a compelling strategy for addressing acquired radiation resistance, optimizing the local antitumour effects of radiotherapy while simultaneously activating systemic antitumour immunity.

Delivery of Cu(II) and Mn(II) by polydopamine-modified nanoparticles for combined photothermal and chemotherapy

Chemodynamic therapy (CDT) has been recognized as an emerging therapeutic strategy. It has attracted considerable attention in recent years as it can generate the most harmful reactive oxygen species (ROS)-hydroxyl radicals (•OH) through the Fenton reaction or a Fenton-like reaction under the catalysis of versatile metal cations, such as, Fe(II), Fe(III), Cu(I), Mn(II), and Mn(III). However, a large number of reducing species (e.g., GSH) in tumors inhibit the therapeutic effects of CDT. This study proposes a nanocarrier strategy that can release versatile metal cations in the initial stage to consume the reducing substances, which can be convenient for subsequent CDT treatment. A novel nano-delivery system based on H-MnO2@PDA/Cu-CD@Ad-TK-Ad@Ploy-CD (abbreviated as MNZ) was proposed to resolve the above problems. Herein, hollow mesoporous manganese dioxide nanoparticles (H-MnO2) were coated with PDA and modified with copper ions on the surface of PDA. The PDA was then functionalized with β-cyclodextrin (β-CD) substitutions that were further assembled with N-((1S,3R,5S)-adamantan-1-yl)-3-((2-((3-(((3s,5s,7s)-adamantan-1-yl)amino)-3-oxopropyl)thio)propan-2-yl)thio)propenamide (Ad-TK-Ad). Poly-CD was assembled with CD to improve the stability of the reactor. The MNZ nanotheranostic platform can release Cu(II) and Mn(II), which could react with intracellular GSH to consume the reducing substances in tumors. Subsequently, H2O2 can be converted into •OH, and the effect is improved with increasing temperatures. Cytotoxicity of MNZ (200 μg mL-1) was studied by cell counting kit-8 (CCK-8) assay using HeLa cells as the models. Results indicated that cell viability was clearly reduced to 22% by the nanoparticles alone, to 18% by the nanoparticles with H2O2, and to 9% by the nanoparticles with H2O2 and NIR, under weak acidic condition (pH 6.8). This work provides a beneficial exploration for the application of nano-delivery strategies for combined photothermal and chemodynamic therapy agents.

Full-active pharmaceutical ingredient nanosensitizer for augmented photoimmunotherapy by synergistic mitochondria targeting and immunogenic death inducing

The precise and effective activation of the immune response is crucial in promising therapy curing cancer. Photoimmunotherapy (PIT) is an emerging strategy for precise regulation and highly spatiotemporal selectivity. However, this approach faces a significant challenge due to the off-target effect and the immunosuppressive microenvironment. To address this challenge, a nanoscale full-active pharmaceutical ingredient (API) photo-immune stimulator was developed. This formulation overcomes the limitations of PIT by strengthening the ability to penetrate tumors deeply and inducing precise and potent mitochondria-targeted dual-mode photodynamic therapy and photothermal therapy. Along with inhibiting overexpressed Hsp90, this nanosensitizer in turn improves the immunosuppressive microenvironment. Ultimately, this mitochondria-targeted PIT demonstrated potent antitumor efficacy, achieving a remarkable inhibition rate of ≥95% for both established primary tumors and distant abscopal tumors. In conclusion, this novel self-delivery full-API nanosystem enhances the efficacy of phototherapy and reprograms the immunosuppressive microenvironment, thereby holding great promise in the development of precise and effective immunotherapy.

Oxygen self-supplying nanoradiosensitizer activates cGAS-STING pathway to enhance radioimmunotherapy of triple negative breast cancer

Radiotherapy (RT)-mediated immune activation is insufficient for effective therapy of triple-negative breast cancer (TNBC) due to the immunosuppressive tumor microenvironment. Herein, we developed an oxygen self-supplying nanoradiosensitizer to activate immunogenic cell death (ICD) and the cGAS-STING signaling pathway, elevating the anti-tumor immune response and improving radioimmunotherapy for TNBC. The nanoradiosensitizer was fabricated using astragaloside liposome-encapsulated FePt alloy and MnO nanocrystals (ALFM). The ALFM targeted the glucose transporter-1 (GLUT-1) receptor in TNBC and effectively entered tumor cells. Subsequently, the ALFM responded to the weakly acidic tumor microenvironment and degraded, releasing FePt and Mn2+ ions. The released Mn2+ ions not only elevated cellular ROS levels via a Fenton-like reaction but also activated the cGAS-STING signaling pathway, which stimulated the anti-tumor immune response. In addition, the FePt alloy catalyzed a cascade reaction, producing ROS and O2 in tumor cells, alleviating tumor hypoxia, and enhancing the RT effect. Besides, ROS-mediated cell damage induced the ICD effect in TNBC, promoted dendritic cell maturation and the infiltration of cytotoxic T lymphocytes, ultimately eliciting cancer immunotherapy. In vivo experimental results demonstrated that ALFM effectively activated the antitumor immune response and improved the radioimmunotherapy effect for TNBC. Overall, this work presents an effective strategy for enhanced radioimmunotherapy of TNBC. Subsequently, the ALFM responded to weak acidic tumor microenvironment, and then degraded along with the release of FePt and Mn2+ ions. The released Mn2+ ions not only elevated cellular ROS level via Fenton-like reaction, but also activated cGAS-STING signal pathway, which activated anti-tumor immune response. In addition, FePt alloy catalyzed cascade reaction and then produced ROS and O2 in tumor cells, relieving tumor hypoxia and enhancing RT effect. Besides, ROS-mediated cell damage induced ICD effect of TNBC, promoted dendritic cells maturation and the infiltration of cytotoxic T lymphocytes, eventually elicited antitumor immunotherapy. In vivo experimental results demonstrated that ALFM effectively activated antitumor immune response, improved radioimmunotherapy effect of TNBC. Overall, this work provided a complete new strategy for enhanced radioimmunotherapy of TNBC.

Two-dimensional coordination risedronate-manganese nanobelts as adjuvant for cancer radiotherapy and immunotherapy

The irradiated tumor itself represents an opportunity to establish endogenous in situ vaccines. However, such in situ cancer vaccination (ISCV) triggered by radiation therapy (RT) alone is very weak and hardly elicits systemic anticancer immunity. In this study, we develop two-dimensional risedronate-manganese nanobelts (RMn-NBs) as an adjuvant for RT to address this issue. RMn-NBs exhibit good T2 magnetic resonance imaging performance and enhanced Fenton-like catalytic activity, which induces immunogenic cell death. RMn-NBs can inhibit the HIF-1α/VEGF axis to empower RT and synchronously activate the cGAS/STING pathway for promoting the secretion of type I interferon, thereby boosting RT-triggered ISCV and immune checkpoint blockade therapy against primary and metastatic tumors. RMn-NBs as a nano-adjuvant for RT show good biocompatibility and therapeutic efficacy, presenting a promising prospect for cancer radiotherapy and immunotherapy.

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.

Tumor Microenvironment Specific Regulation Ca-Fe-Nanospheres for Ferroptosis-Promoted Domino Synergistic Therapy and Tumor Immune Response

Reactive oxygen species (ROS)-mediated emerging treatments exhibit unique advantages in cancer therapy in recent years. While the efficacy of ROS-involved tumor therapy is greatly restricted by complex tumor microenvironment (TME). Herein, a dual-metal CaO2@CDs-Fe (CCF) nanosphere, with TME response and regulation capabilities, are proposed to improve ROS lethal power by a multiple cascade synergistic therapeutic strategy with domino effect. In response to weak acidic TME, CCF will decompose, accompanied with intracellular Ca2+ upregulated and abundant H2O2 and O2 produced to reverse antitherapeutic TME. Then the exposed CF cores can act as both Fenton agent and sonosensitizer to generate excessive ROS in the regulated TME for enhanced synergistic CDT/SDT. In combination with calcium overloading, the augmented ROS induced oxidative stress will cause more severe mitochondrial damage and cellular apoptosis. Furthermore, CCF can also reduce GPX4 expression and enlarge the lipid peroxidation, causing ferroptosis and apoptosis in parallel. These signals of damage will finally initiate damage-associated molecular patterns to activate immune response and to realize excellent antitumor effect. This outstanding domino ROS/calcium loading synergistic effect endows CCF with excellent anticancer effect to efficiently eliminate tumor by apoptosis/ferroptosis/ICD both in vitro and in vivo.

High doses of radiation cause cochlear immunological stress and sensorineural hearing loss

Radiotherapy is a crucial treatment for head and neck malignancies, but it can sometimes cause sensorineural hearing loss (SNHL). Changes in the immune microenvironment and sensory neuroepithelium of the inner ear after radiation exposure remain poorly understood. This study investigated cochlear morphology and macrophages in the inner ear after high-dose irradiation. The heads of heterozygous 8-week-old Cx3cr1GFP/+ male mice were irradiated with 30Gy of X-rays and biological samples were collected on days 1, 7, and 10 after irradiation. Auditory brainstem responses were used to assess auditory function in the mice. Changes in basilar membrane hair cells, spiral ganglion neurons (SGN), and inner ear macrophages were observed using hematoxylin-eosin (HE) staining and immunofluorescence staining. The expression of inflammatory mediators in the inner ear was detected by quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) in cochlear tissue. The results showed no significant hair cell loss after a single high dose of radiation. However, the mice developed pantonal hearing loss on day 10 when HE staining revealed SGN atrophy and immunofluorescence showed decreased neurofilament expression. The number of macrophages in the inner ear reduced over time. RT-qPCR showed that cochlear inflammatory factors and chemokines were briefly upregulated on day 1st after irradiation and then decreased over time. In conclusion, high-dose irradiation causes acute SNHL that is not associated with hair cell loss and may be related to SGN changes. Radiation-induced SNHL is associated with a reduction in cochlear macrophages and changes in the immune microenvironment, but the relationship between the two remains to be investigated.

Multifunctional single-component photosensitizers as metal-free ferroptosis inducers for enhanced photodynamic immunotherapy

Immunotherapy can enhance primary tumor efficacy, restrict distant growth, and combat lung metastasis. Unfortunately, it remains challenging to effectively activate the immune response. Here, tertiary butyl, methoxy, and triphenylamine (TPA) were utilized as electron donors to develop multifunctional photosensitizers (PSs). CNTPA-TPA, featuring TPA as the donor (D) and cyano as the acceptor (A), excelled in reactive oxygen species (ROS) generation due to its smaller singlet-triplet energy gap (ΔES-T) and larger spin-orbit coupling constant (SOC). Additionally, cyano groups reacted with glutamate (Glu) and glutathione (GSH), reducing intracellular GSH levels. This not only enhanced PDT efficacy but also triggered redox dyshomeostasis-mediated ferroptosis. The positive effects of photodynamic therapy (PDT) and ferroptosis promoted immunogenic cell death (ICD) and immune activation. By further combining anti-programmed cell death protein ligand-1 (anti-PD-L1) antibody, the powerful treatments of ferroptosis-assisted photodynamic immunotherapy significantly eradicated the primary tumors, inhibited the growth of distant tumors, and suppressed lung metastasis. In this study, a three-pronged approach was realized by single-component CNTPA-TPA, which simultaneously served as metal-free ferroptosis inducers, type-I photosensitizers, and immunologic adjuvants for near-infrared fluorescence imaging (NIR FLI)-guided multimodal phototheranostics of tumor. STATEMENT OF SIGNIFICANCE: (1) CNTPA-TPA shared the smallest singlet-triplet energy gap and the largest spin-orbit coupling constant, which boosted intersystem crossing for efficient type-I photodynamic therapy (PDT); (2) Special reactions between cyano groups with glutamate and glutathione in mild conditions restricted the biosynthesis of intracellular GSH. GSH-depletion efficiently induced glutathione peroxidase 4 inactivation and lipid peroxide, resulting in ferroptosis of tumor cells; (3) The combination treatments of ferroptosis-assisted photodynamic immunotherapy induced by single-component CNTPA-TPA with the participation of anti-PD-L1 antibody resulted in increased T-cell infiltration and profound suppression of both primary and distant tumor growth, as well as lung metastasis.

Reactive oxygen species of tumor microenvironment: Harnessing for immunogenic cell death

The tumor microenvironment (TME) is a dynamic and complex system that undergoes continuous changes in its network architecture, notably affecting redox homeostasis. These alterations collectively shape a diverse ecosystem actively supporting tumor progression by influencing the cellular and molecular components of the TME. Despite the remarkable clinical advancements in cancer immunotherapy, its spectrum of clinical utility is limited by the altered TME and inadequate tumor immunogenicity. Recent studies have revealed that some conventional and targeted therapy strategies can augment the efficacy of immunotherapy even in patients with less immunogenic solid tumors. These strategies provoke immunogenic cell death (ICD) through the ROS-dependent liberation of damage-associated molecular patterns (DAMPs). These DAMPs recognize and bind with Pattern Recognition Receptors (PRRs) on immune cells, activating and maturing defense cells, ultimately leading to a robust antitumor immune response. The present review underscores the pivotal role of redox homeostasis in orchestrating the transition of TME from a cold to a hot phenotype and the ROS-ICD axis in immune response induction. Additionally, it provides up-to-date insights into strategies that leverage ROS generation to induce ICD. The comprehensive analysis aims to develop ROS-based effective cancer immunotherapies for less immunogenic tumors.

Rare Earth Nanoprobes for Targeted Delineation of Triple Negative Breast Cancer and Enhancement of Radioimmunotherapy

Radiotherapy demonstrates a synergistic effect with immunotherapy by inducing a transformation of "immune cold" tumors into "immune hot" tumors in triple negative breast cancer (TNBC). Nevertheless, the effectiveness of immunotherapy is constrained by low expression of tumor-exposed antigens, inadequate inflammation, and insufficient tumor infiltrating lymphocyte (TILs). To address this predicament, novel lutecium-based rare earth nanoparticles (RENPs) are synthesized with the aim of amplifying radiation effect and tumor immune response. The nanoprobe is characterized by neodymium-based down-conversion fluorescence, demonstrating robust photostability, biocompatibility, and targetability. The conjugation of RENPs with a CXCR4 targeted drug enables precise delineation of breast tumors using a near-infrared imaging system and improves radiation efficacy via lutetium-based radio-sensitizer in vivo. Furthermore, the study shows a notable enhancement of immune response through the induction of immunogenic cell death and recruitment of TILs, resulting in the inhibition of tumor progression both in vitro and in vivo models following the administration of nanoparticles. Hence, the novel multifunctional nanoprobes incorporating various lanthanide elements offer the potential for imaging-guided tumor delineation, radio-sensitization, and immune activation post-radiation, thus presenting an efficient radio-immunotherapeutic approach for TNBC.

Mitochondria Energy Metabolism Depression as Novel Adjuvant to Sensitize Radiotherapy and Inhibit Radiation Induced-Pulmonary Fibrosis

Currently, the typical combination therapy of programmed death ligand-1 (PD-L1) antibodies with radiotherapy (RT) still exhibits impaired immunogenic antitumor response in clinical due to lessened DNA damage and acquired immune tolerance via the upregulation of some other immune checkpoint inhibitors. Apart from this, such combination therapy may raise the occurrence rate of radiation-induced lung fibrosis (RIPF) due to enhanced systemic inflammation, leading to the ultimate death of cancer patients (average survival time of about 3 years). Therefore, it is newly revealed that mitochondria energy metabolism regulation can be used as a novel effective PD-L1 and transforming growth factor-β (TGF-β) dual-downregulation method. Following this, IR-TAM is prepared by conjugating mitochondria-targeted heptamethine cyanine dye IR-68 with oxidative phosphorylation (OXPHOS) inhibitor Tamoxifen (TAM), which then self-assembled with albumin (Alb) to form IR-TAM@Alb nanoparticles. By doing this, tumor-targeting IR-TAM@Alb nanoparticle effectively reversed tumor hypoxia and depressed PD-L1 and TGF-β expression to sensitize RT. Meanwhile, due to the capacity of heptamethine cyanine dye in targeting RIPF and the function of TAM in depressing TGF-β, IR-TAM@Alb also ameliorated fibrosis development induced by RT.

PAD4 Inhibitor-Functionalized Layered Double Hydroxide Nanosheets for Synergistic Sonodynamic Therapy/Immunotherapy Of Tumor Metastasis

Sonodynamic therapy (SDT) is demonstrated to trigger the systemic immune response of the organism and facilitate the treatment of metastatic tumors. However, SDT-mediated neutrophil extracellular traps (NETs) formation can promote tumor cell spread, thus weakening the therapeutic effectiveness of metastatic tumors. Herein, the amorphous CoW-layered double hydroxide (a-CoW-LDH) nanosheets are functionalized with a peptidyl arginine deiminase 4 (PAD4) inhibitor, i.e., YW3-56, to construct a multifunctional nanoagent (a-LDH@356) for synergistic SDT/immunotherapy. Specifically, a-CoW-LDH nanosheets can act as a sonosensitizer to generate abundant reactive oxygen species (ROS) under US irradiation. After loading with YW3-56, a-LDH@356 plus US irradiation not only effectively induces ROS generation and immunogenic cell death, but also inhibits the elevation of citrullinated histone H3 (H3cit) and the release of NETs, enabling a synergistic enhancement of anti-tumor metastasis effect. Using 4T1 tumor model, it is demonstrated that combining a-CoW-LDH with YW3-56 stimulates an anti-tumor response by upregulating the proportion of immune-activated cells and inducing polarization of M1 macrophages, and inhibits immune escape by downregulating the expression of PD-1 on immune cells under US irradiation, which not only arrests primary tumor progression with a tumor inhibition rate of 69.5% but also prevents tumor metastasis with the least number of lung metastatic nodules.

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

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

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.

Self-Cascade Nanozyme Reactor as a Cuproptosis Inducer Synergistic Inhibition of Cellular Respiration Boosting Radioimmunotherapy

Intrinsic or acquired radioresistance remained an important challenge in the successful management of cancer. Herein, a novel "smart" multifunctional copper-based nanocomposite (RCL@Pd@CuZ) to improve radiotherapy (RT) sensitivity is designed and developed. In this nanoplatform, DSPE-PEG-RGD modified on the liposome surface enhanced tumor targeting and permeability; capsaicin inserted into the phospholipid bilayer improved the hypoxic conditions in the tumor microenvironment (TME) by inhibiting mitochondrial respiration; a Cu MOF porous cube encapsulated in liposome generated highly active hydroxyl radicals (OH·), consumed GSH and promoted cuproptosis by releasing Cu2+; the ultrasmall palladium (Pd) nanozyme within the cubes exhibited peroxidase activity, catalyzing toxic OH· generation and releasing oxygen from hydrogen peroxide; and lastly, Pd, as an element with a relatively high atomic number (Z) enhanced the photoelectric and Compton effects of X-rays. Therefore, RCL@Pd@CuZ enhance RT sensitivity by ameliorating hypoxia, promoting cuproptosis, depleting GSH, amplifying oxidative stress, and enhancing X-ray absorption  , consequently potently magnifying immunogenic cell death (ICD). In a mouse model , RCL@Pd@CuZ combined with RT yielded >90% inhibition compared with that obtained by RT alone in addition to a greater quantity of DC maturation and CD8+ T cell infiltration. This nanoplatform offered a promising remedial modality to facilitate cuproptosis-related cancer radioimmunotherapy.

Immunomodulatory Precision: A Narrative Review Exploring the Critical Role of Immune Checkpoint Inhibitors in Cancer Treatment

An immune checkpoint is a signaling pathway that regulates the recognition of antigens by T-cell receptors (TCRs) during an immune response. These checkpoints play a pivotal role in suppressing excessive immune responses and maintaining immune homeostasis against viral or microbial infections. There are several FDA-approved immune checkpoint inhibitors (ICIs), including ipilimumab, pembrolizumab, and avelumab. These ICIs target cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death ligand 1 (PD-L1). Furthermore, ongoing efforts are focused on developing new ICIs with emerging potential. In comparison to conventional treatments, ICIs offer the advantages of reduced side effects and durable responses. There is growing interest in the potential of combining different ICIs with chemotherapy, radiation therapy, or targeted therapies. This article comprehensively reviews the classification, mechanism of action, application, and combination strategies of ICIs in various cancers and discusses their current limitations. Our objective is to contribute to the future development of more effective anticancer drugs targeting immune checkpoints.