Binary regulation of the tumor microenvironment by a pH-responsive reversible shielding nanoplatform for improved tumor chemo-immunotherapy

Discovery of Cu(II)-Dipyridophenazine Complex for Synergistic Cuproptosis/Chemodynamic Therapy via Disrupting the Tricarboxylic Acid (TCA) Cycle in Metastatic TNBC

Cuproptosis, a recently recognized regulated cell death, distinct from established death mechanisms, offers promising cancer therapy. However, its efficacy relies on intracellular copper availability and homeostasis. Herein, a novel Copper(II) dipyridohenazine complex, Cu(L1)2Cl acts as an oxidative stress amplifier and glutathione (GSH) disrupter for synergistic cuproptosis/chemodynamic anticancer therapy for the treatment of challenging triple negative breast cancer. Cu(L1)2Cl followed the endocytosis pathway to enter tumor cells and depleted GSH to release Cu+ ions which result in the production of.OH radicals generated from H2O2, leading to chemodynamic therapy. The spike in ROS generation disrupts cellular redox homeostasis, causing impaired mitochondrial function, ATP depletion, and endoplasmic reticulum stress generation. ATP depletion directly affects the function of copper-transporting ATPase 1 (ATP7A), resulting in a large amount of Cu+ trapped inside cancer cells, causing oligomerization of dihydrolipoamide S-acetyltransferase (DLAT), and depletion of Lipoyl synthase (LIAS), and leading to cellular cuproptosis. Subsequently, Cu(L1)2Cl interrupts tumor metastasis and evokes immunogenic cell death (ICD) by promoting high mobility group protein (HMGB1), ATP and lactate dehydrogenase (LDH) release, calreticulin (CRT) exposure, and inhibiting programmed death ligand 1 (PD-L1). The in vivo studies on 4T1 tumor bearing Balb/c mice validate its potent antitumor efficacy, thereby providing a new therapeutic paradigm to augment cuproptosis-related therapies.

Biomimic Nanodrugs Overcome Tumor Immunosuppressive Microenvironment to Enhance Cuproptosis/Chemodynamic-Induced Cancer Immunotherapy

Elesclomol (ES) as an efficient Cu ionophore can specifically transport Cu into mitochondria and disrupt intracellular Cu homeostasis. Extra intracellular Cu induces cuproptosis and chemodynamic therapy (CDT), which further cascades immunogenic cell death (ICD) and activates antitumor immune responses. However, the tumor immunosuppressive microenvironment (TIM) attenuates the efficiency of the immune response. Herein, a biomimic nanodrug (ECNM) is fabricated, of which ES, Cu2+ and NLG919 (an IDO1 inhibitor) are integrated via a self-assembly process and subsequently coated with 4T1 cell membrane. ECNM can overcome the typical drawbacks of ES, ameliorating the stability and half-life of ES by membrane-coating and enhancing its tumor accumulation and internalization via homotypic targeting. It is worth mentioning that, the addition of NLG919 is also beneficial to the system circulation stability of ES and reduces the non-specific ES release. After internalization, ECNM dissociates via the glutathione-responsive process and exhibits comprehensive antitumor capabilities, including cuproptosis, CDT and TIM reversing, thereby eliciting ICD and optimizing the antitumor immune response. Furthermore, ECNM not only accelerates tumor regression but also gains a strong abscopal effect and displays the potential of tumor vaccination. Overall, ECNM can activate antitumor immunity via cuproptosis and CDT, together with TIM reversing, for cancer treatment.

Tumor-Targeted Catalytic Immunotherapy

Cancer immunotherapy holds significant promise for improving cancer treatment efficacy; however, the low response rate remains a considerable challenge. To overcome this limitation, advanced catalytic materials offer potential in augmenting catalytic immunotherapy by modulating the immunosuppressive tumor microenvironment (TME) through precise biochemical reactions. Achieving optimal targeting precision and therapeutic efficacy necessitates a thorough understanding of the properties and underlying mechanisms of tumor-targeted catalytic materials. This review provides a comprehensive and systematic overview of recent advancements in tumor-targeted catalytic materials and their critical role in enhancing catalytic immunotherapy. It highlights the types of catalytic reactions, the construction strategies of catalytic materials, and their fundamental mechanisms for tumor targeting, including passive, bioactive, stimuli-responsive, and biomimetic targeting approaches. Furthermore, this review outlines various tumor-specific targeting strategies, encompassing tumor tissue, tumor cell, exogenous stimuli-responsive, TME-responsive, and cellular TME targeting strategies. Finally, the discussion addresses the challenges and future perspectives for transitioning catalytic materials into clinical applications, offering insights that pave the way for next-generation cancer therapies and provide substantial benefits to patients in clinical settings.

Comprehensive insights into glioblastoma multiforme: drug delivery challenges and multimodal treatment strategies

Glioblastoma multiforme (GBM) is one of the most common and malignant brain tumors, with a high prevalence in elderly population. Most chemotherapeutic agents fail to reach the tumor site due to various challenges. However, smart nanocarriers have demonstrated excellent drug-loading capabilities, enabling them to cross the blood brain tumor barrier for the GBM treatment. Surface modification of nanocarriers has significantly enhanced their potential for targeting therapeutics. Moreover, recent innovations in drug therapies, such as the incorporation of theranostic agents in nanocarriers and antibody-drug conjugates, have offered newer insights for both diagnosis and treatment. This review focuses on recent advances in new therapeutic interventions for GBM, with an emphasis on the nanotheranostics systems to maximize therapeutic and diagnostic outcomes.

Cuproptosis in cancer therapy: mechanisms, therapeutic application and future prospects

Cuproptosis is a regulated form of cell death induced by the accumulation of metal ions and is closely linked to aspects of cellular drug resistance, cellular metabolism, and signalling pathways. Due to its crucial role in regulating physiological and pathological processes, cuproptosis has gained increasing significance as a potential target for anticancer drug development. In this review, we introduce the definition of cuproptosis and provide a comprehensive discussion of the mechanisms of cuproptosis. In addition, the methods for the detection of cuproptosis are summarized, and recent advances in cuproptosis in cancer therapy are reviewed, mainly in terms of elesclomol (ES)-mediated cuproptosis and disulfiram (DSF)-mediated cuproptosis, which provided practical value for applications. Finally, the current challenges and future development of cuproptosis-mediated cancer therapy are discussed. In summary, this review highlights recent progress on cuproptosis in cancer therapy, offering novel ideas and strategies for future research and applications.

A Self-Amplifying ROS-Responsive Nanoplatform for Simultaneous Cuproptosis and Cancer Immunotherapy

Cuproptosis is an emerging cell death pathway that depends on the intracellular Cu ions. Elesclomol (ES) as an efficient Cu ionophore can specifically transport Cu into mitochondria and trigger cuproptosis. However, ES can be rapidly removed and metabolized during intravenous administration, leading to a short half-life and limited tumor accumulation, which hampers its clinical application. Here, the study develops a reactive oxygen species (ROS)-responsive polymer (PCP) based on cinnamaldehyde (CA) and polyethylene glycol (PEG) to encapsulate ES-Cu compound (EC), forming ECPCP. ECPCP significantly prolongs the systemic circulation of EC and enhances its tumor accumulation. After cellular internalization, the PCP coating stimulatingly dissociates exposing to the high-level ROS, and releases ES and Cu, thereby triggering cell death via cuproptosis. Meanwhile, Cu2+-stimulated Fenton-like reaction together with CA-stimulated ROS production simultaneously breaks the redox homeostasis, which compensates for the insufficient oxidative stress treated with ES alone, in turn inducing immunogenic cell death of tumor cells, achieving simultaneous cuproptosis and immunotherapy. Furthermore, the excessive ROS accelerates the stimuli-dissociation of ECPCP, forming a positive feedback therapy loop against tumor self-alleviation. Therefore, ECPCP as a nanoplatform for cuproptosis and immunotherapy improves the dual antitumor mechanism of ES and provides a potential optimization for ES clinical application.

Nanoparticle-mediated immunogenic cell death for cancer immunotherapy

The field of cancer therapy is witnessing the emergence of immunotherapy, an innovative approach that activates the body own immune system to combat cancer. Immunogenic cell death (ICD) has emerged as a prominent research focus in the field of cancer immunotherapy, attracting significant attention in recent years. The activation of ICD can induce the release of damage-associated molecular patterns (DAMPs), such as calreticulin (CRT), adenosine triphosphate (ATP), high mobility group box protein 1 (HMGB1), and heat shock proteins (HSP). Subsequently, this process promotes the maturation of innate immune cells, including dendritic cells (DCs), thereby triggering a T cell-mediated anti-tumor immune response. The activation of the ICD ultimately leads to the development of long-lasting immune responses against tumors. Studies have demonstrated that partial therapeutic approaches, such as chemotherapy with doxorubicin, specific forms of radiotherapy, and phototherapy, can induce the generation of ICD. The main focus of this article is to discuss and review the therapeutic methods triggered by nanoparticles for ICD, while briefly outlining their anti-tumor mechanism. The objective is to provide a comprehensive reference for the widespread application of ICD.

Nanoparticles in tumor microenvironment remodeling and cancer immunotherapy

Cancer immunotherapy and vaccine development have significantly improved the fight against cancers. Despite these advancements, challenges remain, particularly in the clinical delivery of immunomodulatory compounds. The tumor microenvironment (TME), comprising macrophages, fibroblasts, and immune cells, plays a crucial role in immune response modulation. Nanoparticles, engineered to reshape the TME, have shown promising results in enhancing immunotherapy by facilitating targeted delivery and immune modulation. These nanoparticles can suppress fibroblast activation, promote M1 macrophage polarization, aid dendritic cell maturation, and encourage T cell infiltration. Biomimetic nanoparticles further enhance immunotherapy by increasing the internalization of immunomodulatory agents in immune cells such as dendritic cells. Moreover, exosomes, whether naturally secreted by cells in the body or bioengineered, have been explored to regulate the TME and immune-related cells to affect cancer immunotherapy. Stimuli-responsive nanocarriers, activated by pH, redox, and light conditions, exhibit the potential to accelerate immunotherapy. The co-application of nanoparticles with immune checkpoint inhibitors is an emerging strategy to boost anti-tumor immunity. With their ability to induce long-term immunity, nanoarchitectures are promising structures in vaccine development. This review underscores the critical role of nanoparticles in overcoming current challenges and driving the advancement of cancer immunotherapy and TME modification.

Stimuli-responsive nanodelivery systems for amplifying immunogenic cell death in cancer immunotherapy

Immunogenic cell death (ICD) is a special pattern of tumor cell death, enabling to elicit tumor-specific immune response via the release of damage-associated molecular patterns and tumor-associated antigens in the tumor microenvironment. ICD-induced immunotherapy holds the promise for completely eliminating tumors and long-term protective antitumor immune response. Increasing ICD inducers have been discovered for boosting antitumor immunity via evoking ICD. Nonetheless, the utilization of ICD inducers remains insufficient owing to serious toxic reactions, low localization efficiency within the tumor microenvironmental niche, etc. For overcoming such limitations, stimuli-responsive multifunctional nanoparticles or nanocomposites with ICD inducers have been developed for improving immunotherapeutic efficiency via lowering toxicity, which represent a prospective scheme for fostering the utilization of ICD inducers in immunotherapy. This review outlines the advances in near-infrared (NIR)-, pH-, redox-, pH- and redox-, or NIR- and tumor microenvironment-responsive nanodelivery systems for ICD induction. Furthermore, we discuss their clinical translational potential. The progress of stimuli-responsive nanoparticles in clinical settings depends upon the development of biologically safer drugs tailored to patient needs. Moreover, an in-depth comprehending of ICD biomarkers, immunosuppressive microenvironment, and ICD inducers may accelerate the advance in smarter multifunctional nanodelivery systems to further amplify ICD.

Acidic environment could modulate the interferon-γ expression: Implication on modulation of cancer and immune cells' interactions

BACKGROUND

In rapidly growing solid tumors, insufficient vascularization and poor oxygen supply result in an acidic tumor microenvironment, which can alter immune response.

OBJECTIVE

To investigate the role of the acidic microenvironment in immune response modulation along with cancer and immune cells' interactions.

METHOD

To mimic the tumor microenvironment conditions, T cells (Jurkat), macrophages (THP-1), and HeLa (cervical) cells were cultured under acidic conditions (pH 6.9, pH 6.5) and physiological pH (7.4). The HeLa cell culture medium was exploited as a tumor cell conditioned medium. Real-time PCR was carried out to quantify the mRNA levels, while flow cytometry and western blot hybridization was carried out to ascertain the levels of different proteins.

RESULTS

The acidic microenvironment around the T cells (Jurkat) and macrophage cells (THP-1) could lead to the downregulation of the interferon gamma (IFN-γ). An increase in IFN-γ expression was observed when Jurkat and macrophage cells were cultured in HeLa cells conditioned medium (HCM) at low pH (pH 6.9, pH 6.5). The HeLa cells under acidic environment (pH 6.9, pH 6.5) upregulated interleukin 18 levels and secreted it as exosome anchored. Additionally, enhanced nuclear localization of NF-κB was observed in Jurkat and THP-1 cells cultured in HCM (pH 6.9, pH 6.5). Jurkat and THP-1 cultured in HCM revealed enhanced cytotoxicity against the HeLa cells upon reverting the pH of the medium from acidic to physiological pH (pH 7.4).

CONCLUSION

Collectively, these results suggest that the acidic microenvironment acted as a key barrier to cancer and immune cells' interactions.

Nano-baicalein facilitates chemotherapy in breast cancer by targeting tumor microenvironment

Cancer-associated fibroblasts constitute a significant component in the tumor microenvironment, playing a pivotal role in tumor proliferation, invasion, migration, and metastasis. Consequently, therapy combining chemotherapeutic agents with tumor microenvironment (TME) modulators appears to be a promising avenue for cancer treatment. In this paper, a tumor microenvironment-based mPEG-PLGA nanoparticle loaded with baicalein (PMs-Ba) was constructed for the purpose of improving the tumor microenvironment in cases of triple-negative breast cancer. The results demonstrate that, on the one hand, PMs-Ba was able to inhibit the transforming growth factor β(TGF-β) signaling pathway to avoid the activation of cancer-associated fibroblasts (CAFs), thereby influencing the interstitial microenvironment of the tumor. On the other hand, the agent led to an increase in the infiltration of cytotoxic T cells, activating the tumor immune microenvironment. Meanwhile, in the murine breast cancer model, an intravenous injection of PMs-Ba combined with doxorubicin nanoparticles (PMs-ADM) significantly improved the antitumor effectiveness. These results suggest that baicalein encapsulated in nanoparticles may be a promising strategy for modulating the TME and for adjuvant chemotherapy, signifying a potential TME-remodeling nanoformulation that could enhance the antitumor efficacy of nanotherapeutics.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

Recent Advances on Surface-Modified GBM Targeted Nanoparticles: Targeting Strategies and Surface Characterization

Glioblastoma multiforme (GBM) is the most common malignant brain tumor, associated with low long-term survival. Nanoparticles (NPs) developed against GBM are a promising strategy to improve current therapies, by enhancing the brain delivery of active molecules and reducing off-target effects. In particular, NPs hold high potential for the targeted delivery of chemotherapeutics both across the blood-brain barrier (BBB) and specifically to GBM cell receptors, pathways, or the tumor microenvironment (TME). In this review, the most recent strategies to deliver drugs to GBM are explored. The main focus is on how surface functionalizations are essential for BBB crossing and for tumor specific targeting. We give a critical analysis of the various ligand-based approaches that have been used to target specific cancer cell receptors and the TME, or to interfere with the signaling pathways of GBM. Despite the increasing application of NPs in the clinical setting, new methods for ligand and surface characterization are needed to optimize the synthesis, as well as to predict their in vivo behavior. An expert opinion is given on the future of this research and what is still missing to create and characterize a functional NP system for improved GBM targeting.

pH-responsive nanoprodrugs combining a Src inhibitor and chemotherapy to potentiate antitumor immunity via pyroptosis in head and neck cancer

As the prominent feature of the development and progression of head and neck squamous cell carcinoma (HNSCC) is immunosuppression, therapeutic strategies to restore antitumor immunity have shown promising prospects. The efficacy of chemotherapy, a mainstay in HNSCC treatment, is exemplified by cytotoxic effects as well as immunostimulation, whereas compensatory activation of prosurvival signals in tumor tissues may compromise its efficacy. Aberrant activation of Src is present in many human malignancies including HNSCC, and is implicated in chemotherapy resistance. In this regard, tumor-microenvironment-responsive prodrug nanomicelles (PDO NPs) are rationally designed to combine chemotherapy (oxaliplatin, OXA) and Src inhibitors (dasatinib, DAS) for HNSCC therapy. PDO NPs are constructed by chemically modifying small-molecule prodrugs (DAS-OXA) loaded in block copolymer iPDPA with pH-triggered transforming capability. PDO NPs can controllably release drugs in response to tumor acidity, thus increasing tumor accumulation and therapeutic efficacy. Moreover, PDO NPs can elicit pyroptosis of tumor cells and induce T-cell-mediated antitumor immunity in murine HNSCC models. In summary, nanoprodrugs integrating Src inhibitors enhance the immunological effects of chemotherapy and provide insight into promising approaches for augmenting immunochemotherapy for HNSCC. STATEMENT OF SIGNIFICANCE: In this study, pH-responsive nanomicelles (PDO NPs) were constructed by loading a small molecular prodrug synthesized by the Src inhibitor dasatinib and the chemotherapy drug oxaliplatin into the amphiphilic block copolymer iPDPA to improve the immunological effects of chemotherapy for HNSCC. These nanomicelles can efficiently accumulate in tumor cells and achieve pH-responsive drug release. The PDO NPs can induce pyroptosis of tumor cells and potentiate antitumor immunity in subcutaneous and syngenetic orthotopic HNSCC mouse models, which may present a promising strategy to enhance immunochemotherapy for HNSCC.

A Self-amplifying ROS-sensitive prodrug-based nanodecoy for circumventing immune resistance in chemotherapy-sensitized immunotherapy

Circumventing immune resistance and boosting immune response is the ultimate goal of cancer immunotherapy. Herein, we reported a tumor-associated macrophage (TAM) membrane-camouflaged nanodecoy containing a self-amplifying reactive oxygen species (ROS)-sensitive prodrug nanoparticle for specifically inducing immunogenic cell death (ICD) in combination with TAM depletion. A versatile ROS-cleavable camptothecin (CPT) prodrug (DCC) was synthesized through a thioacetal linker between CPT and the ROS generator cinnamaldehyde (CA), which could self-assemble into a uniform prodrug nanoparticle to realize a positive feedback loop of "ROS-triggered CA/CPT release and CA/CPT-mediated ROS generation." This DCC was further modified with the TAM membrane (abbreviated as DCC@M2), which could not only target both primary tumors and lung metastasis nodules through VCAM-1/α₄β₁ integrin interaction but also absorb CSF-1 secreted by tumor cells to disturb the interaction between TAMs and cancer cells. Our nanodecoy could effectively induce ICD cascade and deplete TAMs for priming tumor-specific effector T cell infiltration for antitumor immune response activation, which represents a versatile approach for cancer immunotherapy. STATEMENT OF SIGNIFICANCE: A tumor-associated macrophage (TAM) membrane-camouflaged nanodecoy containing a self-amplifying reactive oxygen species (ROS)-sensitive prodrug nanoparticle was fabricated for the first time. This ROS-cleavable camptothecin (CPT)/cinnamaldehyde (CA) prodrug (DCC) could self-assemble into a uniform nanoparticle to realize the positive feedback loop of "ROS-triggered CA/CPT release and CA/CPT-mediated ROS generation." After TAM membrane coating, this system (DCC@M2) could not only target both primary tumors and lung metastatic nodules but also scavenge CSF-1 secreted by tumor cells for TAM depletion for sufficient chemotherapy-sensitized immunotherapy.

A phenolic based tumor-permeated nano-framework for immunogenic cell death induction combined with PD-L1 immune checkpoint blockade

A critical obstacle for programmed death ligand 1 (PD-L1) immune checkpoint blockade immunotherapy is the insufficient T cell infiltration and low immunogenicity of tumor cells. Improving tumor immunogenicity through immunogenic cell death (ICD) can make tumor sensitive to PD-L1 checkpoint blockade immunotherapy. Herein, a phenolic based tumor-permeated nano-framework (EGPt-NF) was fabricated by cross-linking phenylboric acid modified platinum nanoparticles (PBA-Pt, ICD inducer) and epigallocatechin-3-O-gallate (EGCG, PD-L1 inhibitor) via pH-reversible borate ester. In particular, PBA-Pt could not only induce ICD cascade but also relieve tumor hypoxia. Consequently, EGPt-NF could effectively promote dendritic cell maturation and downregulate PD-L1 expression in tumor cells. Furthermore, EGPt-NF could also relieve tumor hypoxia to facilitate cytotoxic T lymphocyte infiltration and IFN-γ secretion. The synergistic effect of EGPt-NF could effectively improve tumor immunogenicity and amplify the therapeutic outcomes of cancer immunotherapy, resulting in a strong antitumor immune response in primary tumor and metastasis inhibition. Our simple approach expands the application of platinum-based drug delivery systems for cancer immunotherapy.