TGF-β blockade-improved chemo-immunotherapy with pH/ROS cascade-responsive micelle via tumor microenvironment remodeling

Advances in tumor stroma-based targeted delivery

The tumor stroma plays a crucial role in tumor progression, and the interactions between the extracellular matrix, tumor cells, and stromal cells collectively influence tumor progression and the efficacy of therapeutic agents. Currently, utilizing components of the tumor stroma for drug delivery is a noteworthy strategy. A number of targeted drug delivery systems designed based on tumor stromal components are entering clinical trials. Therefore, this paper provides a thorough examination of the function of tumor stroma in the advancement of targeted drug delivery systems. One approach is to use tumor stromal components for targeted drug delivery, which includes certain stromal components possessing inherent targeting capabilities like HA, laminin, along with targeting stromal cells homologously. Another method entails directly focusing on tumor stromal components to reshape the tumor stroma and facilitate drug delivery. These drug delivery systems exhibit great potential in more effective cancer therapy strategies, such as precise targeting, enhanced penetration, improved safety profile, and biocompatibility. Ultimately, the deployment of these drug delivery systems can deepen our comprehension of tumor stroma and the advanced development of corresponding drug delivery systems.

Synergistic Potential of Nanomedicine in Prostate Cancer Immunotherapy: Breakthroughs and Prospects

Given the global prevalence of prostate cancer in men, it is crucial to explore more effective treatment strategies. Recently, immunotherapy has emerged as a promising cancer treatment due to its unique mechanism of action and potential long-term effectiveness. However, its limited efficacy in prostate cancer has prompted renewed interest in developing strategies to improve immunotherapy outcomes. Nanomedicine offers a novel perspective on cancer treatment with its unique size effects and surface properties. By employing targeted delivery, controlled release, and enhanced immunogenicity, nanoparticles can be synergized with nanomedicine platforms to amplify the effectiveness of immunotherapy in treating prostate cancer. Simultaneously, nanotechnology can address the limitations of immunotherapy and the challenges of immune escape and tumor microenvironment regulation. Additionally, the synergistic effects of combining nanomedicine with other therapies offer promising clinical outcomes. Innovative applications of nanomedicine include smart nanocarriers, stimulus-responsive systems, and precision medicine approaches to overcome translational obstacles in prostate cancer immunotherapy. This review highlights the transformative potential of nanomedicine in enhancing prostate cancer immunotherapy and emphasizes the need for interdisciplinary collaboration to drive research and clinical applications forward.

Deformable nanocarriers for enhanced drug delivery and cancer therapy

Recently, the field of nanomedicine has witnessed substantial advancements in the development of nanocarriers for targeted drug delivery, emerges as promising platforms to enhance therapeutic efficacy and minimize adverse effects associated with conventional chemotherapy. Notably, deformable nanocarriers have garnered considerable attention due to their unique capabilities of size changeable, tumor-specific aggregation, stimuli-triggered disintegration, and morphological transformations. These deformable nanocarriers present significant opportunities for revolutionizing drug delivery strategies, by responding to specific stimuli or environmental cues, enabling achieved various functions at the tumor site, including size-shrinkage nanocarriers enhance drug penetration, aggregative nanocarriers enhance retention effect, disintegrating nanocarriers enable controlled drug release, and shape-changing nanocarriers improve cellular uptake, allowing for personalized treatment approaches and combination therapies. This review provides an overview of recent developments and applications of deformable nanocarriers for enhancing tumor therapy, underscores the diverse design strategies employed to create deformable nanocarriers and elucidates their remarkable potential in targeted tumor therapy.

Design of a nanozyme-based magnetic nanoplatform to enhance photodynamic therapy and immunotherapy

The tumor microenvironment, particularly the hypoxic property and glutathione (GSH) overexpression, substantially inhibits the efficacy of cancer therapy. In this article, we present the design of a magnetic nanoplatform (MNPT) comprised of a photosensitizer (Ce6) and an iron oxide (Fe3O4)/manganese oxide (MnO2) composite nanozyme. Reactive oxygen species (ROS), such as singlet oxygen (1O2) radicals produced by light irradiation and hydroxyl radicals (·OH) produced by catalysis, are therapeutic species. These therapeutic substances stimulate cell apoptosis by increasing oxidative stress. This apoptosis then triggers the immunological response, which combines photodynamic therapy and T-cell-mediated immunotherapy to treat cancer. Furthermore, MNPT can be utilized as a contrast agent in magnetic resonance and fluorescence dual-modality imaging to give real-time tracking and feedback on treatment.

Redefining drug therapy: innovative approaches using catalytic compartments

INTRODUCTION

Rapid excretion of drug derivatives often results in short drug half-lives, necessitating frequent administrations. Catalytic compartments, also known as nano- and microreactors, offer a solution by providing confined environments for in situ production of therapeutic agents. Inspired by natural compartments, polymer-based catalytic compartments have been developed to improve reaction efficiency and enable site-specific therapeutic applications.

AREAS COVERED

Polymer-based compartments provide stability, permeability control, and responsiveness to stimuli, making them ideal for generating localized compounds/signals. These sophisticated systems, engineered to carry active compounds and enable selective molecular release, represent a significant advancement in pharmaceutical research. They mimic cellular functions, creating controlled catalytic environments for bio-relevant processes. This review explores the latest advancements in synthetic catalytic compartments, focusing on design approaches, building blocks, active molecules, and key bio-applications.

EXPERT OPINION

Catalytic compartments hold transformative potential in precision medicine by improving therapeutic outcomes through precise, on-site production of therapeutic agents. While promising, challenges like scalable manufacturing, biodegradability, and regulatory hurdles must be addressed to realize their full potential. Addressing these will be crucial for their successful application in healthcare.

Recent progress in stimuli-responsive polymeric micelles for targeted delivery of functional nanoparticles

Stimuli-responsive polymeric micelles have emerged as a revolutionary approach for enhancing the in vivo stability, biocompatibility, and targeted delivery of functional nanoparticles (FNPs) in biomedicine. This article comprehensively reviews the preparation methods of these polymer micelles, detailing the innovative strategies employed to introduce stimulus responsiveness and surface modifications essential for precise targeting. We delve into the breakthroughs in utilizing these micelles to selectively deliver various FNPs including magnetic nanoparticles, upconversion nanoparticles, gold nanoparticles, and quantum dots, highlighting their transformative impact in the biomedical realm. Concluding, we present an insight into the current research landscape, addressing the challenges at hand, and envisioning the future trajectory in this burgeoning domain. Join us as we navigate the exciting confluence of polymer science and nanotechnology in reshaping biomedical solutions.

Engineered Nanomaterials for Tumor Immune Microenvironment Modulation in Cancer Immunotherapy

Tumor immunotherapy, represented by immune checkpoint blocking and chimeric antigen receptor (CAR) T cell therapy, has achieved promising results in clinical applications. However, it faces challenges that hinder its further development, such as limited response rates and poor tumor permeability. The efficiency of tumor immunotherapy is also closely linked to the structure and function of the immune microenvironment where the tumor resides. Recently, nanoparticle-based tumor immune microenvironment (TIME) modulation strategies have attracted a great deal of attention in cancer immunotherapy. This is primarily due to the distinctive physical characteristics of nanoparticles, which enable them to effectively infiltrate the TIME and selectively modulate its key constituents. This paper reviews recent advances in nanoparticle engineering to improve anti-cancer immunotherapy. Emerging nanoparticle-based approaches for modulating immune cells, tumor stroma, cytokines and immune checkpoints are discussed, aiming to overcome current challenges in the clinic. In addition, integrating immunotherapy with various treatment modalities such as chemotherapy and photodynamic therapy can be facilitated through the utilization of nanoparticles, thereby enhancing the efficacy of cancer treatment. The future challenges and opportunities of using nanomaterials to reeducate the suppressive immune microenvironment of tumors are also discussed, with the aim of anticipating further advancements in this growing field.

Biopolymer-based tumor microenvironment-responsive nanomedicine for targeted cancer therapy

Nanomedicine has opened up new avenues for cancer treatment by enhancing drug solubility, permeability and targeted delivery to cancer cells. Despite its numerous advantages over conventional therapies, nanomedicine may exhibit off-target drug distribution, harming nontarget regions. The increased permeation and retention effect of nanomedicine in tumor sites also has its limitations, as abnormal tumor vasculature, dense stroma structure and altered tumor microenvironment (TME) may result in limited intratumor distribution and therapeutic failure. However, TME-responsive nanomedicine has exhibited immense potential for efficient, safe and precise delivery of therapeutics utilizing stimuli specific to the TME. This review discusses the mechanistic aspects of various TME-responsive biopolymers and their application in developing various types of TME-responsive nanomedicine.

Arresting the G2/M phase empowers synergy in magnetic nanomanipulator-based cancer mechanotherapy and chemotherapy

Using mechanical cues for cancer cells can realize precise control and efficient therapeutic effects. However, the cell cycle-specific response for dynamic mechanical manipulation is barely investigated. Here, RGD-modified iron oxide nanomanipulators were utilized as the intracellular magneto-mechanical transducers to investigate the mechanical impacts on the cell cycle under a dynamic magnetic field for cancer treatment. The G2/M phase was identified to be sensitive to the intracellular magneto-mechanical modulation with a synergistic treatment effect between the pretreatment of cell cycle-specific drugs and the magneto-mechanical destruction, and thus could be an important mechanical-targeted phase for regulation of cancer cell death. Finally, combining the cell cycle-specific drugs with magneto-mechanical manipulation could significantly inhibit glioma and breast cancer growth in vivo. This intracellular mechanical stimulus showed cell cycle-dependent cytotoxicity and could be developed as a spatiotemporal therapeutic modality in combination with chemotherapy drugs for treating deep-seated tumors.

An Adjuvant Micelle-Based Multifunctional Nanosystem for Tumor Immunotherapy by Remodeling Three Types of Immunosuppressive Cells

Immunotherapy is restricted by a complex tumor immunosuppressive microenvironment (TIM) and low drug delivery efficiency. Herein, a multifunctional adjuvant micelle nanosystem (PPD/MPC) integrated with broken barriers and re-education of three classes of immune-tolerant cells is constructed for cancer immunotherapy. The nanosystem significantly conquers the penetration barrier via the weakly acidic tumor microenvironment-responsive size reduction and charge reversal strategy. The detached core micelle MPC could effectively be internalized by tumor-associated macrophages (TAMs), tumor-infiltrating dendritic cells (TIDCs), and myeloid-derived suppressor cells (MDSCs) via mannose-mediated targeting endocytosis and electrostatic adsorption pathways, promoting the re-education of immunosuppressive cells for allowing them to reverse from pro-tumor to antitumor phenotypes by activating TLR4/9 pathways. This process in turn leads to the remodeling of TIM. In vitro and in vivo studies collectively indicate that the adjuvant micelle-based nanosystem not only relieves the intricate immune tolerance and remodels TIM via reprogramming the three types of immunosuppressive cells and regulating the secretion of relevant cytokines/immunity factors but also strengthens immune response and evokes immune memory, consequently suppressing the tumor growth and metastasis.

Calcium Carbonate/Polydopamine Composite Nanoplatform Based on TGF-β Blockade for Comfortable Cancer Immunotherapy

Cancer pain seriously reduces the quality of life of cancer patients. However, most research about cancer focuses solely on inhibiting tumor growth, neglecting the issue of cancer pain. Therefore, the development of therapeutic agents with both tumor suppression and cancer pain relief is crucial to achieve human-centered treatment. Here, the work reports curcumin (CUR) and ropivacaine (Ropi) coincorporating CaCO3/PDA nanoparticles (CaPNMCUR+Ropi) that realized efficient tumor immunotherapy and cancer pain suppression. The therapeutic efficiency and mechanism are revealed in vitro and in vivo. The results indicate that CaPNMCUR+Ropi underwent tumor microenvironment-responsive degradation and realized rapid release of calcium ions, Ropi, and CUR. The excessive intracellular calcium triggered the apoptosis of tumor cells, and the transient pain caused by the tumor injection was relieved by Ropi. Simultaneously, CUR reduced the levels of immunosuppressive factor (TGF-β) and inflammatory factor (IL-6, IL-1β, and TNF-α) in the tumor microenvironment, thereby continuously augmenting the immune response and alleviating inflammatory pain of cancer animals. Meanwhile, the decrease of TGF-β leads to the reduction of transient receptor potential vanilloid 1 (TRPV1) expression, thereby alleviating hyperalgesia and achieving long-lasting analgesic effects. The design of the nanosystem provides a novel idea for human-centered tumor treatment in the future.

Characterization of m6A methylation modifications in gastric cancer

Widely recognized as an essential epitranscriptomic modification, RNA N6-methyladenosine (m6A) is involved in both physiological and pathological processes. Here, we want to investigate m6A modification's potential roles in gastric cancer. Gastric cancer samples were selected from TCGA-STAD and GEO (GSE84426, GSE84433) datasets. Based on 18 regulators of m6A, m6A modification patterns were thoroughly evaluated in gastric cancer samples. Principal component analysis algorithms were used to construct the m6Ascore, using which, m6A modification features in tumor somatic mutations and immune checkpoint blockade therapy were analyzed. 34 gastric cancer samples were collected to verify the effectiveness of the m6Ascore. Here, we determined three different m6A modification patterns. m6Acluster-C modification pattern presented immune activation-associated enrichment pathways and have significant survival advantages. Then, in gastric cancer, m6Ascore could act as an independent prognostic biomarker. A significant survival benefit was exhibited in patients with high m6Ascore. Moreover, the modification signature of m6A uncovered in this study would help to predict immune checkpoint blockade therapy's responses. In conclusion, our discoveries all pointed to the fact that modification patterns of m6A were linked to the TME. Moreover, evaluation of individual tumor's m6A modification pattern will help to guide immunotherapy strategies that shows more therapeutic effects.

Responsive Microneedles as a New Platform for Precision Immunotherapy

Microneedles are a well-known transdermal or transdermal drug delivery system. Different from intramuscular injection, intravenous injection, etc., the microneedle delivery system provides unique characteristics for immunotherapy administration. Microneedles can deliver immunotherapeutic agents to the epidermis and dermis, where immune cells are abundant, unlike conventional vaccine systems. Furthermore, microneedle devices can be designed to respond to certain endogenous or exogenous stimuli including pH, reactive oxygen species (ROS), enzyme, light, temperature, or mechanical force, thereby allowing controlled release of active compounds in the epidermis and dermis. In this way, multifunctional or stimuli-responsive microneedles for immunotherapy could enhance the efficacy of immune responses to prevent or mitigate disease progression and lessen systemic adverse effects on healthy tissues and organs. Since microneedles are a promising drug delivery system for accurate delivery and controlled drug release, this review focuses on the progress of using reactive microneedles for immunotherapy, especially for tumors. Limitations of current microneedle system are summarized, and the controllable administration and targeting of reactive microneedle systems are examined.

Cascade amplification of tumor chemodynamic therapy and starvation with re-educated TAMs via Fe-MOF based functional nanosystem

Tumor microenvironment is characterized by the high concentration of reactive oxygen species (ROS), which is an effective key used to open the Pandora's Box against cancer. Herein, a tumor-targeted nanosystem HFNP@GOX@PFC composed of ROS-cleaved Fe-based metal-organic framework, hyaluronic acid (HA), glucose oxidase (GOX) and perfluorohexane (PFC) has been developed for tumor cascade amplified starvation and chemodynamic therapy (CDT). In response to the high concentration of hydrogen peroxide (H₂O₂) intratumorally, HFNP@GOX@PFC endocytosed by tumor cells can specially be disassembled and release GOX, PFC and Fe²⁺, which can collectively starve tumor and self-produce additional H₂O₂ via competitively glucose catalyzing, supply oxygen to continuous support GOX-mediated starvation therapy, initiate CDT and cascade amplify oxidative stress via Fe²⁺-mediated Fenton reaction, leading to the serious tumor damage with activated p53 signal pathway. Moreover, HFNP@GOX@PFC also significantly initiates antitumor immune response via re-educating tumor-associated macrophages (TAMs) by activating NF-κB and MAPK signal pathways. In vitro and in vivo results collectively demonstrate that nanosystem not only continuously initiates starvation therapy, but also pronouncedly cascade-amplify CDT and polarize TAMs, consequently efficiently inhibiting tumor growth with good biosafety. The functional nanosystem combined the cascade amplification of starvation and CDT provides a new nanoplatform for tumor therapy.

A critical review on the dissemination of PH and stimuli-responsive polymeric nanoparticular systems to improve drug delivery in cancer therapy

Stimuli-responsive nanocarriers have the potential to revolutionize cancer treatment by allowing precise delivery of drugs to the site of disease. The use of polymeric nanocarriers with surfaces that respond to triggers such as pH, light, temperature, and redox potential enables targeted drug distribution. pH is a particularly useful tool, as the lower pH in tumour microenvironments can trigger changes in drug release. Recent advances in the development of pH-responsive polymer nanoparticles have shown great promise for improved in vivo drug delivery, reduced negative drug responses, and more precise drug distribution. A deeper understanding of these nanocarriers will allow us to overcome the challenges of targeted cancer treatment and create a better drug delivery system.

In Situ Polymerization of Aniline Derivative in Vivo for NIR-II Phototheranostics of Tumor

Natural biopolymers can be controllably in situ synthesized in organisms and play important roles in biological activities. Inspired by this, the manipulation of in situ biosynthesis of functional polymers in vivo will be an important way to obtain materials for meeting biological requirements. Herein, in situ biosynthesis of functional conjugated polymer at the tumor site was achieved via the utilization of specific tumor microenvironment (TME) characteristics for the first time. Specially, a water-soluble aniline dimer derivative (N-(3-sulfopropyl) p-aminodiphenylamine, SPA) was artfully in situ polymerized into polySPA (PSPA) nanoparticles at the tumor site, which was activated via the catalysis of hydrogen peroxide (H₂O₂) overexpressed in TME to produce hydroxyl radical (•OH) by coinjected horseradish peroxidase (HRP). Benefiting from outstanding near-infrared (NIR)-II absorption of PSPA, the in situ polymerization process can be validly monitored by photoacoustic (PA) signal at the NIR-II region. Meanwhile, in situ polymerization would induce the size of polymeric materials from small to large, improving the distribution and retention of PSPA at the tumor site. On the combination of NIR-II absorption of PSPA and the size variation induced by polymerization, such polymerization can be applied for tumor-specific NIR-II light mediated PA image and photothermal inhibition of tumors, enhancing the precision and efficacy of tumor phototheranostics. Therefore, the present work opens the way to manipulate TME-activated in situ biosynthesis of functional conjugated polymer at the tumor site for overcoming formidable challenges in tumor theranostics.

Robust Construction of Supersmall Zwitterionic Micelles Based on Hyperbranched Polycarbonates Mediates High Tumor Accumulation

Despite the numerous advantages of nanomedicines, their therapeutic efficacy is hampered by biological barriers, including fast in vivo clearance, poor tumor accumulation, inefficient penetration, and cellular uptake. Herein, cross-linked supersmall micelles based on zwitterionic hyperbranched polycarbonates can overcome these challenges for efficiently targeted drug delivery. Biodegradable acryloyl/zwitterion-functionalized hyperbranched polycarbonates are synthesized by a one-pot sequential reaction of Michael-type addition and ring-opening polymerization, followed by controlled modification with carboxybetaine thiol. Cross-linked supersmall zwitterionic micelles (X-CBMs) are readily prepared by straightforward self-assembly and UV cross-linking. X-CBMs exhibit prolonged blood circulation because of their cross-linked structure and zwitterion decoration, which resist protein corona formation and facilitate escaping RES recognition. Combined with the advantage of supersmall size (7.0 nm), X-CBMs mediate high tumor accumulation and deep penetration, which significantly enhance the targeted antitumor outcome against the 4T1 tumor model by administration of the paclitaxel (PTX) formulation (X-CBM@PTX).

Lysosomal-mediated drug release and activation for cancer therapy and immunotherapy

The development of carrier systems that are able to transport and release therapeutics to target cells is an emergent strategy to treat cancer; however, they following endocytosis are usually trapped in the endo/lysosomal compartments. The efficacy of drug conjugates and nanotherapeutics relies critically on their intracellular drug release ability, for which advanced systems responding to the unique lysosomal environment such as acidic pH and abundant enzymes (e.g. cathepsin B, sulfatase and β-glucuronidase) or equipped with photochemical internalization property have been energetically pursued. In this review, we highlight the recent designs of smart systems that promote efficient lysosomal release and/or escape of anticancer agents including chemotherapeutics (e.g. doxorubicin, platinum, chloroquine and hydrochloroquine) and biotherapeutics (e.g. proteins, siRNA, miRNA, mRNA and pDNA) to cancer cells or immunotherapeutic agents (e.g. antigens, mRNA and immunoadjuvants) to antigen-presenting cells (APCs), thereby boosting cancer therapy and immunotherapy. Lysosomal-mediated drug release presents an appealing approach to develop innovative cancer therapeutics and immunotherapeutics.

Peritumoral scaffold neutralizes tumor pH for chemotherapy sensitization and metastasis inhibition

The abnormal metabolism of rapidly growing tumors can create an acidic tumor microenvironment (TME) that renders cancer cells resistant to chemotherapy and further facilitates endothelial-to-mesenchymal transition (EMT) progress to promote metastasis. Here, we developed a combination strategy consisting of (1) peritumorally injected scaffold that alleviates TME acidosis, and (2) intravenously injected nanoparticles that delivers anti-cancer agents to tumor. Concurrent treatment with these two drug delivery systems profoundly delayed the growth of primary tumor and reduced the spontaneous metastasis to lung in an orthotopic breast cancer mouse model. Mechanism studies both in vitro and in vivo further revealed that neutralization of TME pH by the hydrogel scaffold sensitized cancer cells to nanoparticle-based chemotherapy, thereby strengthening the cytotoxicity against tumor growth; In parallel, reversal of tumor acidity downregulated various pro-metastatic proteins intratumorally to block the EMT progress, thereby reducing the metastatic potential of cancer cells. This work provided proof-of-concept demonstration that chemotherapy sensitization and EMT suppression could be synchronized by the modulation of TME pH, which may be potentially beneficial for simultaneous inhibition of tumor growth and cancer metastasis.

Chemotherapy Mediated by Biomimetic Polymeric Nanoparticles Potentiates Enhanced Tumor Immunotherapy via Amplification of Endoplasmic Reticulum Stress and Mitochondrial Dysfunction

Construction of multifunctional nanoplatforms to elevate chemotherapeutic efficacy and induce long-term antitumor immunity still remains to be an extreme challenge. Herein, the design of an advanced redox-responsive nanomedicine formulation based on phosphorus dendrimer-copper(II) complexes (1G₃ -Cu)- and toyocamycin (Toy)-loaded polymeric nanoparticles (GCT NPs) coated with cancer cell membranes (CM) are reported. The designed GCT@CM NPs with a size of 210 nm are stable under physiological conditions but are rapidly dissociated in the reductive tumor microenvironment to deplete glutathione and release drugs. The co-loading of 1G₃ -Cu and Toy within the NPs causes significant tumor cell apoptosis and immunogenic cell death through 1G₃ -Cu-induced mitochondrial dysfunction and Toy-mediated amplification of endoplasmic reticulum stress, respectively, thus effectively suppressing tumor growth, promoting dendritic cell maturation, and increasing tumor-infiltrating cytotoxic T lymphocytes. Likewise, the coated CM and the loaded 1G₃ -Cu render the GCT@CM NPs with homotypic targeting and T₁ -weighted magnetic resonance imaging of tumors, respectively. With the assistance of programmed cell death ligand 1 antibody, the GCT@CM NP-mediated chemotherapy can significantly potentiate tumor immunotherapy for effective inhibition of tumor recurrence and metastasis. The developed GCT@CM NPs hold a great potential for chemotherapy-potentiated immunotherapy of different tumor types through different mechanisms or synergies.

Dual-responsive nanosystem based on TGF-β blockade and immunogenic chemotherapy for effective chemoimmunotherapy

The antitumor immune response induced by chemotherapy has attracted considerable attention. However, the immunosuppressive tumor microenvironment hinders the immune activation effect of cancer chemotherapy. TGF-β plays a key role in driving tumor immunosuppression and can prevent effective antitumor immune response through multiple roles. In this study, a dual-responsive prodrug micelle (PAOL) is designed to co-deliver LY2109761 (a TGF-β receptor I/II inhibitor) and oxaliplatin (OXA, a conventional chemotherapy) to remodel tumor microenvironment and trigger immunogenic cell death (ICD) to induce antitumor immunity response. Under hypoxia tumor environment, the polyethylene glycol shell of the micelle cleavages, along with the release of LY2109761 and OXA prodrug. Cytotoxic effect of OXA is then activated by glutathione-mediated reduction in tumor cells and the activated OXA significantly enhances tumor immunogenicity and promotes intratumoral accumulation of cytotoxic T lymphocytes. Meanwhile, TGF-β blockade through LY2109761 reprograms tumor microenvironment by correcting the immunosuppressive state and regulating tumor extracellular matrix, which further maintaining OXA induced immune response. Therefore, due to the capability of boosting tumor-specific antitumor immunity, the bifunctional micelle presents markedly synergistic antitumor efficacies and provides a potent therapeutic strategy for chemoimmunotherapy of solid tumors.

Advances in Intelligent-Responsive Nanocarriers for Cancer Therapy

With the rapid development of nanotechnology, strategies related to nanomedicine have been used to overcome the shortcomings of traditional chemotherapy drugs, thereby demonstrating significant potential for innovative drug delivery. Nanomaterials play an increasingly important role in cancer immunotherapy. Stimuli-responsive nanomaterials enable the precise control of drug release through exposure to specific stimuli and exhibit excellent specificity in response to various stimuli. Immunomodulators carried by nanomaterials can also effectively regulate the immune system and significantly improve their therapeutic effect on cancer. In recent years, stimuli-responsive nanomaterials have evolved rapidly from single stimuli-responsive systems to multi-stimuli-responsive systems. This review focuses on recent advances in the design and applications of stimuli-responsive nanomaterials, including exogenous and endogenous responsive nanoscale drug delivery systems, which show extraordinary potential in intelligent drug delivery for multimodal cancer diagnosis and treatment. Ultimately, the opportunities and challenges in the development of intelligent responsive nanomaterials are briefly discussed according to recent advances in multi-stimuli-responsive systems.

Codelivery of Shikonin and siTGF-β for enhanced triple negative breast cancer chemo-immunotherapy

Although chemoimmunotherapy has achieved considerable success in cancer treatment in recent years, the cure for triple-negative breast cancer (TNBC) remains elusive. The unsatisfied outcomes are likely attributed to deficient tumor immunogenicity, a strong immunosuppressive tumor microenvironment (ITM) and tumor metastasis. To address this issue, we constructed an effective codelivery system, combined with tumor growth factor β (TGF-β) small interference RNA (siTGF-β) and shikonin (SK), to achieve successful chemoimmunotherapy of TNBC. The SK/siTGF-β NPs (approximately 110 nm) exhibited a uniform structure and good stability. Conjugated FA presented enhanced cellular uptake in 4 T1 cells, and siTGF-β escaped from lysosomes because of the "proton sponge" effect of PEI. Furthermore, SK actually induced satisfactory immunogenic cell death (ICD) and the resulting dendritic cell (DC) maturation facilitated a distinctly enhanced cytotoxic T lymphocyte (CTL) response, generating a positive effect on tumor suppression. Simultaneously, the successful silencing of TGF-β alleviated the TGF-β-mediated ITM and inhibited the epithelial-to-mesenchymal transition (EMT), contributing to the infiltration of CTLs, suppression of regulatory T lymphocyte (Treg) proliferation and lung metastasis inhibition. Thus, the SK/siTGF-β NPs demonstrated the strongest therapeutic effect with delayed tumor growth (TIR = 88.5%) and lung metastasis restraint (77.3%). More importantly, tumor rechallenge assay suggested that the codelivery system produced a long-term immunological memory response to prevent tumor recurrence. Based on boosting the immune response and combating the ITM, SK/siTGF-β NPs would be a potential approach for TNBC therapy.

Charge reversal nano-systems for tumor therapy

Surface charge of biological and medical nanocarriers has been demonstrated to play an important role in cellular uptake. Owing to the unique physicochemical properties, charge-reversal delivery strategy has rapidly developed as a promising approach for drug delivery application, especially for cancer treatment. Charge-reversal nanocarriers are neutral/negatively charged at physiological conditions while could be triggered to positively charged by specific stimuli (i.e., pH, redox, ROS, enzyme, light or temperature) to achieve the prolonged blood circulation and enhanced tumor cellular uptake, thus to potentiate the antitumor effects of delivered therapeutic agents. In this review, we comprehensively summarized the recent advances of charge-reversal nanocarriers, including: (i) the effect of surface charge on cellular uptake; (ii) charge-conversion mechanisms responding to several specific stimuli; (iii) relation between the chemical structure and charge reversal activity; and (iv) polymeric materials that are commonly applied in the charge-reversal delivery systems.

Nanomaterials with changeable physicochemical property for boosting cancer immunotherapy

The past decade has witnessed a great progress in cancer immunotherapy with the sequential approvals of therapeutic cancer vaccine, immune checkpoint inhibitor and chimeric antigen receptor (CAR) T cell therapy. However, some hurdles still remain to the wide implementation of cancer immunotherapy, including low immune response, complex tumor heterogeneity, off-target immunotoxicity, poor solid tumor infiltration, and immune evasion-induced treatment tolerance. Owing to changeable physicochemical properties in response to endogenous or exogenous stimuli, nanomaterials hold the remarkable potential in incorporation of multiple agents, efficient biological barrier penetration, precise immunomodulator delivery, and controllable content release for boosting cancer immunotherapy. Herein, we review the recent advances in nanomaterials with changeable physicochemical property (NCPP) to develop cancer vaccine, remold tumor microenvironment and evoke direct T cell activation. Besides, we provide our outlook on this emerging field at the intersection of NCPP design and cancer immunotherapy.