Radioactive nano-oxygen generator enhance anti-tumor radio-immunotherapy by regulating tumor microenvironment and reducing proliferation

Antioxidant Enzymes and Their Potential Use in Breast Cancer Treatment

According to the World Health Organization (WHO), breast cancer (BC) is the deadliest and the most common type of cancer worldwide in women. Several factors associated with BC exert their effects by modulating the state of stress. They can induce genetic mutations or alterations in cell growth, encouraging neoplastic development and the production of reactive oxygen species (ROS). ROS are able to activate many signal transduction pathways, producing an inflammatory environment that leads to the suppression of programmed cell death and the promotion of tumor proliferation, angiogenesis, and metastasis; these effects promote the development and progression of malignant neoplasms. However, cells have both non-enzymatic and enzymatic antioxidant systems that protect them by neutralizing the harmful effects of ROS. In this sense, antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), thioredoxin reductase (TrxR), and peroxiredoxin (Prx) protect the body from diseases caused by oxidative damage. In this review, we will discuss mechanisms through which some enzymatic antioxidants inhibit or promote carcinogenesis, as well as the new therapeutic proposals developed to complement traditional treatments.

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

Immunotherapy harnesses the inherent immune system in the body to generate systemic antitumor immunity, offering a promising modality for defending against cancer. However, tumor immunosuppression and evasion seriously restrict the immune response rates in clinical settings. Catalytic nanomedicines can transform tumoral substances/metabolites into therapeutic products in situ, offering unique advantages in antitumor immunotherapy. Through catalytic reactions, both tumor eradication and immune regulation can be simultaneously achieved, favoring the development of systemic antitumor immunity. In recent years, with advancements in catalytic chemistry and nanotechnology, catalytic nanomedicines based on nanozymes, photocatalysts, sonocatalysts, Fenton catalysts, electrocatalysts, piezocatalysts, thermocatalysts and radiocatalysts have been rapidly developed with vast applications in cancer immunotherapy. This review provides an introduction to the fabrication of catalytic nanomedicines with an emphasis on their structures and engineering strategies. Furthermore, the catalytic substrates and state-of-the-art applications of nanocatalysts in cancer immunotherapy have also been outlined and discussed. The relationships between nanostructures and immune regulating performance of catalytic nanomedicines are highlighted to provide a deep understanding of their working mechanisms in the tumor microenvironment. Finally, the challenges and development trends are revealed, aiming to provide new insights for the future development of nanocatalysts in catalytic immunotherapy.

Nanofabrications of Erythrocyte Membrane-Coated Telmisartan Delivery System Effective for Radiosensitivity of Tumor Cells in Mice Model

Background

Radiation stimulates the secretion of tumor stroma and induces resistance, recurrence, and metastasis of stromal-vascular tumors during radiotherapy. The proliferation and activation of tumor-associated fibroblasts (TAFs) are important reasons for the production of tumor stroma. Telmisartan (Tel) can inhibit the proliferation and activation of TAFs (resting TAFs), which may promote radiosensitization. However, Tel has a poor water solubility.

Methods

In this study, self-assembled telmisartan nanoparticles (Tel NPs) were prepared by aqueous solvent diffusion method to solve the insoluble problem of Tel and achieve high drug loading of Tel. Then, erythrocyte membrane (ECM) obtained by hypotonic lysis was coated on the surface of Tel NPs (ECM/Tel) for the achievement of in vivo long circulation and tumor targeting. Immunofluorescence staining, western blot and other biological techniques were used to investigate the effect of ECM/Tel on TAFs activation inhibition (resting effect) and mechanisms involved. The multicellular spheroids (MCSs) model and mouse breast cancer cells (4T1) were constructed to investigate the effect of ECM/Tel on reducing stroma secretion, alleviating hypoxia, and the corresponding promoting radiosensitization effect in vitro. A mouse orthotopic 4T1 breast cancer model was constructed to investigate the radiosensitizing effect of ECM/Tel on inhibiting breast cancer growth and lung metastasis of breast cancer.

Results

ECM/Tel showed good physiological stability and tumor-targeting ability. ECM/Tel could rest TAFs and reduce stroma secretion, alleviate hypoxia, and enhance penetration in tumor microenvironment. In addition, ECM/Tel arrested the cell cycle of 4T1 cells to the radiosensitive G2/M phase. In mouse orthotopic 4T1 breast cancer model, ECM/Tel played a superior role in radiosensitization and significantly inhibited lung metastasis of breast cancer.

Conclusion

ECM/Tel showed synergistical radiosensitization effect on both the tumor microenvironment and tumor cells, which is a promising radiosensitizer in the radiotherapy of stroma-vascular tumors.

Nanozyme-Coated Bacteria Hitchhike on CD11b+ Immune Cells to Boost Tumor Radioimmunotherapy

Bacterial-based delivery strategies have recently emerged as a unique research direction in the field of drug delivery. However, bacterial vectors are quickly phagocytosed by immune cells after entering the bloodstream. Taking advantage of this phenomenon, herein, this work seeks to harness the potential of immune cells to delivery micron-sized bacterial vectors, and find that inactivated bacterial can accumulate at tumor-site after intravenous injection through CD11b+ cells hitchhiking. To this end, this work then designs a gold-platinum bimetallic nanozyme coated bacterial vector (Au-Pt@VNP20009, APV). Utilizing strong tumor inflammatory response induced by low dose X-rays, this work further heightens the ability of CD11b+ immune cells to assist APV hitchhiking for tumor-targeted delivery, which can significantly relieve tumor hypoxia and immunosuppression, and inhibit tumor growth and metastasis. This work elucidates the potential mechanisms of bacterial vector targeted delivery, opening up new horizons for bacterial vector delivery strategies and clinical tumor radioimmunotherapy.

Nanotechnology Reprogramming Metabolism for Enhanced Tumor Immunotherapy

Mutation burden, hypoxia, and immunoediting contribute to altered metabolic profiles in tumor cells, resulting in a tumor microenvironment (TME) characterized by accumulation of toxic metabolites and depletion of various nutrients, which significantly hinder the antitumor immunity via multiple mechanisms, hindering the efficacy of tumor immunotherapies. In-depth investigation of the mechanisms underlying these phenomena are vital for developing effective antitumor drugs and therapies, while the therapeutic effects of metabolism-targeting drugs are restricted by off-target toxicity toward effector immune cells and high dosage-mediated side effects. Nanotechnologies, which exhibit versatility and plasticity in targeted delivery and metabolism modulation, have been widely applied to boost tumor immunometabolic therapies via multiple strategies, including targeting of metabolic pathways. In this review, recent advances in understanding the roles of tumor cell metabolism in both immunoevasion and immunosuppression are reviewed, and nanotechnology-based metabolic reprogramming strategies for enhanced tumor immunotherapies are discussed.

A continuously efficient O2-supplying strategy for long-term modulation of hypoxic tumor microenvironment to enhance long-acting radionuclides internal therapy

Radionuclides internal radiotherapy (RIT) is a clinically powerful method for cancer treatment, but still poses unsatisfactory therapeutic outcomes due to the hypoxic characteristic of tumor microenvironment (TME). Catalase (CAT) or CAT-like nanomaterials can be used to enzymatically decompose TME endogenous H2O2 to boost TME oxygenation and thus alleviate the hypoxic level within tumors, but their effectiveness is still hindered by the short-lasting of hypoxia relief owing to their poor stability or degradability, thereby failing to match the long therapeutic duration of RIT. Herein, we proposed an innovative strategy of using facet-dependent CAT-like Pd-based two-dimensional (2D) nanoplatforms to continuously enhance RIT. Specifically, rationally designed 2D Pd@Au nanosheets (NSs) enable consistent enzymatic conversion of endogenous H2O2 into O2 to overcome hypoxia-induced RIT resistance. Furthermore, partially coated Au layer afford NIR-II responsiveness and moderate photothermal treatment that augmenting their enzymatic functionality. This approach with dual-effect paves the way for reshaping TME and consequently facilitating the brachytherapy ablation of cancer. Our work offers a significant advancement in the integration of catalytic nanomedicine and nuclear medicine, with the overarching goal of amplifying the clinical benefits of RIT-treated patients.

Radiotherapy combined with nano-biomaterials for cancer radio-immunotherapy

Radiotherapy (RT) plays an important role in tumor therapy due to its noninvasiveness and wide adaptation. In recent years, radiation therapy has been discovered to induce an anti-tumor immune response, which arouses widespread concern among scientists and clinicians. In this review, we highlight recent advances in the applications of nano-biomaterials for radiotherapy-activated immunotherapy. We first discuss the combination of different radiosensitizing nano-biomaterials and immune checkpoint inhibitors to enhance tumor immune response and improve radiotherapy efficacy. Subsequently, various nano-biomaterials-enabled tumor oxygenation strategies are introduced to alleviate the hypoxic tumor environment and amplify the immunomodulatory effect. With the aid of nano-vaccines and adjuvants, radiotherapy refreshes the host's immune system. Additionally, ionizing radiation responsive nano-biomaterials raise innate immunity-mediated anti-tumor immunity. At last, we summarize the rapid development of immune modulatable nano-biomaterials and discuss the key challenge in the development of nano-biomaterials for tumor radio-immunotherapy. Understanding the nano-biomaterials-assisted radio-immunotherapy will maximize the benefits of clinical radiotherapy and immunotherapy and facilitate the development of new combinational therapy modality.

Radionuclide-Labeled Microspheres for Radio-Immunotherapy of Hepatocellular Carcinoma

Brachytherapy, including radioactive seed implantation (RSI) and transarterial radiation therapy embolization (TARE), is an important treatment modality for advanced hepatocellular carcinoma (HCC), but the inability of RSI and TARE to treat tumor metastasis and recurrence limits their benefits for patients in the clinic. Herein, indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors-loaded alginate microspheres (IMs) are developed as radionuclide carriers with immunomodulatory functions to achieve effective radio-immunotherapy. The size and swelling properties of IMs can be facilely tailored by adjusting the calcium source during emulsification. Small/large IMs(SIMs/LIMs) are biocompatible and available for RSI and TARE, respectively, after 177 Lu labeling. Among them, 177 Lu-SIMs completely eliminated subcutaneous HCC in mice after intratumoral RSI. Moreover, in combination with anti-PD-L1, 177 Lu-SIMs not only eradicate primary tumors by RSI but also effectively inhibit the growth of distant tumors, wherein the potent abscopal effect can be ascribed to the immune stimulation of RSI and the modulation of the tumor immune microenvironment (TIME) by IDO1 inhibitors. In parallel, LIMs demonstrate excellent embolization efficiency, resulting in visible necrotic lesions in the central auricular artery of rabbits, which are promising for TARE in future studies. Collectively, a versatile therapeutic agent is provided to synchronously modulate the TIME during brachytherapy for efficient radio-immunotherapy of advanced HCC.

A novel anoikis-related gene prognostic signature and its correlation with the immune microenvironment in colorectal cancer

Background: Anoikis is a type of apoptosis associated with cell detachment. Resistance to anoikis is a focal point of tumor metastasis. This study aimed to explore the relationship among anoikis-related genes (ARGs), immune infiltration, and prognosis in colorectal cancer (CRC). Methods: The transcriptome profile and clinical data on patients with CRC were retrieved from The Cancer Genome Atlas and Gene Expression Omnibus databases. Patients were divided into two clusters based on the expression of ARGs. Differences between the two ARG molecular subtypes were analyzed in terms of prognosis, functional enrichment, gene mutation frequency, and immune cell infiltration. An ARG-related prognostic signature for predicting overall survival in patients with CRC was developed and validated using absolute value convergence and selection operator (LASSO) regression analysis. The correlation between the signature risk score and clinicopathological features, immune cell infiltration, immune typing, and immunotherapy response was analyzed. The risk score combined with clinicopathological characteristics was used to construct a nomogram to assess CRC patients' prognosis. Results: Overall, 151 ARGs were differentially expressed in CRC. Two ARG subtypes, namely, ARG-high and ARG-low groups, were identified and correlated with CRC prognosis. The gene mutation frequency and immune, stromal, and ESTIMATE scores of the ARG-high group were higher than those of the ARG-low group. Moreover, CD8, natural killer cells, M1 macrophages, human leukocyte antigen (HLA), and immune checkpoint-related genes were significantly increased in the ARG-high group. An optimized 25-gene CRC prognostic signature was successfully constructed, and its prognostic predictive ability was validated. The high-risk score was correlated with T, N, M, and TNM stages. Risk scores were negatively correlated with dendritic cells, eosinophils, and CD4 cells, and significantly positively correlated with regulatory T cells. Patients in the high-risk group were more likely to exhibit immune unresponsiveness. Finally, the nomogram model was constructed and showed good prognostic predictive power. Conclusion: ARGs are associated with clinicopathological features and the prognosis of CRC, and play important roles in the immune microenvironment. Herein, we underpinned the usefulness of ARGs in CRC to develop more effective immunotherapy techniques.

Nattokinase-Mediated Regulation of Tumor Physical Microenvironment to Enhance Chemotherapy, Radiotherapy, and CAR-T Therapy of Solid Tumor

The therapy of solid tumors is always hampered by the intrinsic tumor physical microenvironment (TPME) featured with compact and rigid extracellular matrix (ECM) microstructures. Herein, we introduce nattokinase (NKase), a thrombolytic healthcare drug, to comprehensively regulate the TPME for versatile enhancement of various therapy modalities. Intratumoral injection of NKase not only degrades the major ECM component fibronectin but also inhibits cancer-associated fibroblasts (CAFs) in generating fibrosis, resulting in decreased tumor stiffness, enhanced perfusion, and hypoxia alleviation. The NKase-mediated regulation of the TPME significantly promotes the tumoral accumulation of therapeutic agents, leading to efficient chemotherapy without inducing side effects. Additionally, the enhancement of tumor radiotherapy based on radiosensitizers was also achieved by the pretreatment of intratumorally injected NKase, which could be ascribed to the elevated oxygen saturation level in NKase-treated tumors. Moreover, a xenografted human breast MDB-MA-231 tumor model is established to evaluate the influence of NKase on chimeric antigen receptor (CAR)-T cell therapy, illustrating that the pretreatment of NKase could boost the infiltration of CAR-T cells into tumors and thus be a benefit for tumor inhibition. These findings demonstrate the great promise of the NKase-regulated TPME as a translational strategy for universal enhancement of therapeutic efficacy in solid tumors by various treatments.

Large Range Atomic Force Microscopy with High Aspect Ratio Micropipette Probe for Deep Trench Imaging

Atomic force microscopy (AFM) has been adopted in both industry and academia for high-fidelity, full-profile topographic characterization. Typically, the tiny tip of the cantilever and the limited traveling range of the scanner restrict AFM measurement to relatively flat samples (recommend 1 µm). The primary objective of this work is to address these limitations using a large-range AFM (measuring height >10 µm) system consisting of a novel repairable high aspect ratio probe (HARP) with a nested-proportional-integral-derivative (nested-PID) AFM system. The HARP is fabricated using a reliable, cost-efficient bench-top process. The tip is then fused by pulling the end of the micropipette cantilever with a length up to hundreds of micrometers and a tip diameter of 30 nm. The design, simulation, fabrication, and performance of the HARP are described herein. This instrument is then tested using polymer trenches which reveals superior image fidelity compared to standard silicon tips. Finally, a nested-PID system is developed and employed to facilitate 3D characterization of 50-µm-step samples. The results demonstrate the efficacy of the proposed bench-top technique for the fabrication of low-cost, simple HAR AFM probes that facilitate the imaging of samples with deep trenches.

Emerging role of hypoxia-inducible factor-1α in inflammatory autoimmune diseases: A comprehensive review

Hypoxia-inducible factor-1α (HIF-1α) is a primary metabolic sensor, and is expressed in different immune cells, such as macrophage, dendritic cell, neutrophil, T cell, and non-immune cells, for instance, synovial fibroblast, and islet β cell. HIF-1α signaling regulates cellular metabolism, triggering the release of inflammatory cytokines and inflammatory cells proliferation. It is known that microenvironment hypoxia, vascular proliferation, and impaired immunological balance are present in autoimmune diseases. To date, HIF-1α is recognized to be overexpressed in several inflammatory autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis, and function of HIF-1α is dysregulated in these diseases. In this review, we narrate the signaling pathway of HIF-1α and the possible immunopathological roles of HIF-1α in autoimmune diseases. The collected information will provide a theoretical basis for the familiarization and development of new clinical trials and treatment based on HIF-1α and inflammatory autoimmune disorders in the future.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

New advances in pharmaceutical strategies for sensitizing anti-PD-1 immunotherapy and clinical research

Attempts have been made continuously to use nano-drug delivery system (NDDS) to improve the effect of antitumor therapy. In recent years, especially in the application of immunotherapy represented by antiprogrammed death receptor 1 (anti-PD-1), it has been vigorously developed. Nanodelivery systems are significantly superior in a number of aspects including increasing the solubility of insoluble drugs, enhancing their targeting ability, prolonging their half-life, and reducing side effects. It can not only directly improve the efficacy of anti-PD-1 immunotherapy, but also indirectly enhance the antineoplastic efficacy of immunotherapy by boosting the effectiveness of therapeutic modalities such as chemotherapy, radiotherapy, photothermal, and photodynamic therapy (PTT/PDT). Here, we summarize the studies published in recent years on the use of nanotechnology in pharmaceutics to improve the efficacy of anti-PD-1 antibodies, analyze their characteristics and shortcomings, and combine with the current clinical research on anti-PD-1 antibodies to provide a reference for the design of future nanocarriers, so as to further expand the clinical application prospects of NDDSs. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Harnessing bioactive nanomaterials in modulating tumor glycolysis-associated metabolism

Glycolytic reprogramming is emerging as a hallmark of various cancers and a promising therapeutic target. Nanotechnology is revolutionizing the anti-tumor therapeutic approaches associated with glycolysis. Finely controlled chemical composition and nanostructure provide nanomaterials unique advantages, enabling an excellent platform for integrated drug delivery, biochemical modulation and combination therapy. Recent studies have shown promising potential of nanotherapeutic strategies in modulating tumor glycolytic metabolism alone or in combination with other treatments such as chemotherapy, radiotherapy and immunotherapy. To foster more innovation in this cutting-edge and interdisciplinary field, this review summarizes recent understandings of the origin and development of tumor glycolysis, then provides the latest advances in how nanomaterials modulate tumor glycolysis-related metabolism. The interplay of nanochemistry, metabolism and immunity is highlighted. Ultimately, the challenges and opportunities are presented.

Antitumor Activity of the Zinc Oxide Nanoparticles Coated with Low-Molecular-Weight Heparin and Doxorubicin Complex In Vitro and In Vivo

Various metal oxide nanomaterials have been widely used as carriers to prepare pH-sensitive nanomedicines to respond to the acidic tumor microenvironment promoting antitumor efficiency. Herein, we used zinc oxide nanoparticles (ZnO NPs) as metal oxide nanomaterial coated with low-molecular-weight heparin (LMHP) and doxorubicin (DOX) complex (LMHP-DOX) to prepare ZnO-LD NPs for controllable pH-triggered DOX release on the targeted site. Our results indicated that the released DOX from ZnO-LD NPs was pH-sensitive. The oxygen produced by ZnO-LD NPs in H₂O₂ solution was observed in in vitro experiment. The ZnO-LD NPs entered into both PC-3M and 4T1 tumor cells via clathrin-mediated endocytosis and micropinocytosis pathway. The intracellular reactive oxygen species (ROS) generated by ZnO-LD NPs could significantly increase the caspase 3/7 level, leading to tumor cell apoptosis. The in vitro and in vivo antitumor activity was confirmed in PC-3M and 4T1 cell lines or tumor-bearing mice models. The in vivo and in vitro tumor images via second-order nonlinearity of ZnO-LD NPs indicated that ZnO-LD NPs could penetrate deep into the tumor tissues. Therefore, the ZnO-LD NPs developed in our study could provide an efficient approach for the preparation of pH-sensitive nano delivery systems suitable for tumor therapy and imaging.

An NIR-II Photothermally Triggered "Oxygen Bomb" for Hypoxic Tumor Programmed Cascade Therapy

Hypoxia, as a characteristic feature of solid tumors, has a close relationship with tumor resistance to photodynamic therapy (PDT) and chemotherapy. Perfluorocarbon (PFC) is reported to relieve hypoxic in solid tumors by acting as an oxygen carrier via several nanostructures. However, the oxygen delivery process is mostly driven by a concentration gradient, which is uncontrollable. Herein, a photothermally controlled "oxygen bomb" PSPP-Au₉₈₀ -D is designed by encapsulating a PFC core within a functionalized bilayer polymer shell. Near-infrared second window photothermal agent gold nanorods with excellent photo-to-heat energy-conversion ability are fabricated on the surface of the polymer shell via an innovative modified two-step seedless ex situ growth process to thermally trigger O₂  release. Then, a programmed cascade therapy strategy is customized for hypoxic orthotopic pancreatic cancer. First, PSPP-Au₉₈₀ -D is irradiated by a 980 nm laser to photothermally trigger O₂  infusing into the hypoxic tumor microenvironment, which is accompanied by local hyperemia and doxorubicin release. Subsequently, a 680 nm laser is used to generate singlet oxygen in the oxygenated tumor microenvironment for PDT. This choreographed programmed cascade therapy strategy will provide a new route for suppressing hypoxic tumor growth under mild conditions based on controllable and effective oxygen release.

131I-αPD-L1 immobilized by bacterial cellulose for enhanced radio-immunotherapy of cancer

Radioisotope therapy (RIT) of cancer is restrained by the nonspecific distribution of radioisotope and ineptitude for metastatic tumors. Meanwhile, the clinical application of immune checkpoint blockade (ICB) confronts problems such as low responsive rate, multiple administration requirements and immune-related adverse events (irAE). To address these challenges, we prepared an injectable suspension by immobilizing ¹³¹I-labeled anti-programmed cell death-ligand 1 antibody (αPD-L1) in bacterial cellulose for precise and durable radio-immunotherapy of cancer. The crisscross network structure of bacterial cellulose nanofibers would contribute to the long-term retention of ¹³¹I-labeled αPD-L1 within tumors, which could reduce the side effect stemmed from the nonspecific ¹³¹I distribution in normal tissues. The potent long-term RIT of ¹³¹I, combined with ICB by αPD-L1, could effectively restrain the growth of primary tumor in mice. In addition to the direct killing effect, ¹³¹I-αPD-L1 immobilized by bacterial cellulose could enhance the immunogenic cell death (ICD) of cancer cells, activating the maturation of multiple immune cells to induce a systemic anti-tumor immune effect. Our therapeutic strategy could suppress spontaneous cancer metastasis and prolong the survival time of tumor-bearing mice. This study proposed a new approach for combined radio-immunotherapy and a novel solution for tumor metastasis in advanced-stage cancers.