Enhancing the Accumulation of Polymer Micelles by Selectively Dilating Tumor Blood Vessels with NO for Highly Effective Cancer Treatment

Less is More: Asymmetric D-A Type Agent to Achieve Dynamic Self-Assembled Nanoaggregates for Long-Acting Photodynamic Therapy

To enhance the phototheranostic performance, agents with high reactive oxygen species (ROS) generation, good tumor-targeting ability, and prolonged retention are urgently needed. However, symmetric donor-acceptor (D-A) type agents usually produce spherical nanoaggregates, leading to good tumor targeting but inferior retention. Rod-like nanoaggregates are desired to extend their retention in tumors; however, this remains a challenge. In particular, agents with dynamically changeable shapes that integrate merits of different morphologies are seldomly reported. Therefore, self-assembled organic nanoaggregates with smart shape tunability are designed here using an asymmetric D-A type TIBT. The photoluminescence quantum yield in solids is up to 52.24% for TIBT. TIBT also exhibits high ROS generation in corresponding nanoaggregates (TIBT-NCs). Moreover, dynamic self-assembly in shape changing from nanospheres to nanorods occurrs in TIBT-NCs, contributing to the enhancement of ROS quantum yield from 0.55 to 0.72. In addition, dynamic self-assembly can be observed for both in vitro and in vivo, conferring TIBT-NCs with strong tumor targeting and prolonged retention. Finally, efficient photodynamic therapy to inhibit tumor growth is achieved in TIBT-NCs, with an inhibition rate of 90%. This work demonstrates that asymmetric D-A type agents can play significant roles in forming self-assembled organic nanoaggregates, thus showing great potential in long-acting cancer therapy.

Nanocatalytic Anti-Tumor Immune Regulation

Immunotherapy has brought a new dawn for human being to defeat cancer. Although existing immunotherapy regimens (CAR-T, etc.) have made breakthroughs in the treatments of hematological cancer and few solid tumors such as melanoma, the therapeutic efficacy on most solid tumors is still far from being satisfactory. In recent years, the researches on tumor immunotherapy based on nanocatalytic materials are under rapid development, and significant progresses have been made. Nanocatalytic medicine has been demonstrated to be capable of overcoming the limitations of current clinicnal treatments by using toxic chemodrugs, and exhibits highly attractive advantages over traditional therapies, such as the enhanced and sustained therapeutic efficacy based on the durable catalytic activity, remarkably reduced harmful side-effects without using traditional toxic chemodrugs, and so on. Most recently, nanocatalytic medicine has been introduced in the immune-regulation for disease treatments, especially, in the immunoactivation for tumor therapies. This article presents the most recent progresses in immune-response activations by nanocatalytic medicine-initiated chemical reactions for tumor immunotherapy, and elucidates the mechanism of nanocatalytic medicines in regulating anti-tumor immunity. By reviewing the current research progress in the emerging field, this review will further highlight the great potential and broad prospects of nanocatalysis-based anti-tumor immune-therapeutics.

Recent advance in self-assembled polymeric nanomedicines for gaseous signaling molecule delivery

Gaseous signaling molecules such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2 S) have recently been recognized as essential signal mediators that regulate diverse physiological and pathological processes in the human body. With the evolution of gaseous signaling molecule biology, their therapeutic applications have attracted growing attention. One of the challenges in translational research of gaseous signaling molecules is the lack of efficient and safe delivery systems. To tackle this issue, researchers developed a library of gas donors, which are low molecular weight compounds that can release gaseous signaling molecules upon decomposition under physiological conditions. Despite the significant efforts to control gaseous signaling molecule release from gas donors, the therapeutic potential of gaseous signaling molecules cannot be fully explored due to their unfavorable pharmacokinetics and toxic side effects. Recently, the use of nanoparticle-based gas donors, especially self-assembled polymeric gas donors, have emerged as a promising approach. In this review, we describe the development of conventional small gas donors and the challenges in their therapeutic applications. We then illustrate the concepts and critical aspects for designing self-assembled polymeric gas donors and discuss the advantages of this approach in gasotransmistter delivery. We also highlight recent efforts to develop the delivery systems for those molecules based on self-assembled polymeric nanostructures. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Progress on the pathological tissue microenvironment barrier-modulated nanomedicine

Imbalance in the tissue microenvironment is the main obstacle to drug delivery and distribution in the human body. Before penetrating the pathological tissue microenvironment to the target site, therapeutic agents are usually accompanied by three consumption steps: the first step is tissue physical barriers for prevention of their penetration, the second step is inactivation of them by biological molecules, and the third step is a cytoprotective mechanism for preventing them from functioning on specific subcellular organelles. However, recent studies in drug-hindering mainly focus on normal physiological rather than pathological microenvironment, and the repair of damaged physiological barriers is also rarely discussed. Actually, both the modulation of pathological barriers and the repair of damaged physiological barriers are essential in the disease treatment and the homeostasis maintenance. In this review, we present an overview describing the latest advances in the generality of these pathological barriers and barrier-modulated nanomedicine. Overall, this review holds considerable significance for guiding the design of nanomedicine to increase drug efficacy in the future.

Multifunctional nanostructures: Intelligent design to overcome biological barriers

Over the past three decades, nanoscience has offered a unique solution for reducing the systemic toxicity of chemotherapy drugs and for increasing drug therapeutic efficiency. However, the poor accumulation and pharmacokinetics of nanoparticles are some of the key reasons for their slow translation into the clinic. The is intimately linked to the non-biological nature of nanoparticles and the aberrant features of solid cancer, which together significantly compromise nanoparticle delivery. New findings on the unique properties of tumors and their interactions with nanoparticles and the human body suggest that, contrary to what was long-believed, tumor features may be more mirage than miracle, as the enhanced permeability and retention based efficacy is estimated to be as low as 1%. In this review, we highlight the current barriers and available solutions to pave the way for approved nanoformulations. Furthermore, we aim to discuss the main solutions to solve inefficient drug delivery with the use of nanobioengineering of nanocarriers and the tumor environment. Finally, we will discuss the suggested strategies to overcome two or more biological barriers with one nanocarrier. The variety of design formats, applications and implications of each of these methods will also be evaluated.

Chlorogenic Acid-Conjugated Nanoparticles Suppression of Platelet Activation and Disruption to Tumor Vascular Barriers for Enhancing Drug Penetration in Tumor

Hypercoagulation threatens the lives of cancer patients and cancer progression. Platelet overactivation attributes to the tumor-associated hypercoagulation and maintenance of the tumor endothelial integrity, leading to limited intratumoral perfusion of nanoagents into solid tumors in spite of the enhanced penetration and retention effect (EPR). Therefore, the clinical application of nanotherapeutics in solid cancer still faces great challenges. Herein, this work establishes platelet inhibiting nanoagents based on Fe^III -doped C₃ N₄ coloaded with the chemotherapy drug and the antiplatelet drug chlorogenic acid (CA), further opening tumor vascular endothelial junctions, thereby disrupting the tumor vascular endothelial integrity, and enhancing drug perfusion. Moreover, CA not only damages the cancer cells but also potentiates the cytotoxicity induced by the chemotherapy drug doxorubicin, synergistically ablating the tumor tissue. Further, the introduction of CA relieves the original causes of the hypercoagulable state such as tissue factor (TF), thrombin, and matrix metalloproteinases (MMPs) secreted by cancer cells. It is anticipated that the hypercoagulation- and platelet-inhibition strategy by integration of phenolic acid CA into chemotherapy provides insights into platelet inhibition-assisted theranostics based on nanomedicines.

Recent progress in nitric oxide-generating nanomedicine for cancer therapy

Nitric oxide (NO) is an endogenous, multipotent biological signaling molecule that participates in several physiological processes. Recently, exogenous supplementation of tumor tissues with NO has emerged as a potential anticancer therapy. In particular, it induces synergistic effects with other conventional therapies (such as chemo-, radio-, and photodynamic therapies) by regulating the activity of P-glycoprotein, acting as a vascular relaxant to relieve tumor hypoxia, and participating in the metabolism of reactive oxygen species. However, NO is highly reactive, and its half-life is relatively short after generation. Meanwhile, NO-induced anticancer activity is dose-dependent. Therefore, the targeted delivery of NO to the tumor is required for better therapeutic effects. In the past decade, NO-generating nanomedicines (NONs), which enable sustained and specific NO release in tumor tissues, have been developed for enhanced cancer therapy. This review describes the recent efforts and preclinical achievements in the development of NON-based cancer therapies. The chemical structures employed in the fabrication of NONs are summarized, and the strategies involved in NON-based cancer therapies are elaborated.

Recent advances in diverse nanosystems for nitric oxide delivery in cancer therapy

Gas therapy has been proven to be a promising and advantageous treatment option for cancers. Studies have shown that nitric oxide (NO) is one of the smallest structurally significant gas molecules with great potential to suppress cancer. However, there is controversy and concern about its use as it exhibits the opposite physiological effects based on its levels in the tumor. Therefore, the anti-cancer mechanism of NO is the key to cancer treatment, and rationally designed NO delivery systems are crucial to the success of NO biomedical applications. This review summarizes the endogenous production of NO, its physiological mechanisms of action, the application of NO in cancer treatment, and nano-delivery systems for delivering NO donors. Moreover, it briefly reviews challenges in delivering NO from different nanoparticles and the issues associated with its combination treatment strategies. The advantages and challenges of various NO delivery platforms are recapitulated for possible transformation into clinical applications.

The Intracellular and Extracellular Microenvironment of Tumor Site: The Trigger of Stimuli-Responsive Drug Delivery Systems

The tumor microenvironment (TME), including intracellular and extracellular microenvironment, contains many biochemical indicators (such as acidity/alkalinity, oxygen content, and enzymatic activity) that are different from the normal physiological environment. These abnormal biochemical indicators can accelerate the heterogeneity of tumors, but on the other hand, they also provide opportunities for the design of intelligent drug delivery systems (DDSs). The TME-responsive DDSs have shown great potential in reducing the side effects of chemotherapy and improving the curative effect of tumors. In this review, the abnormal biochemical indicators of TME are introduced in detail from both the extracellular and intracellular aspects. In view of the various physiological barriers encountered during drug delivery, the strategy of constructing TME-responsive DDSs is discussed. By summarizing the typical research progress, the authors prospect the development of TME-responsive DDS in the future.

Photoactivated Release of Nitric Oxide and Antimicrobial Peptide Derivatives for Synergistic Therapy of Bacterial Skin Abscesses

It is of paramount importance to develop novel approaches for combating bacterial resistance and the integration of different antibacterial mechanisms is essential to achieve synergistic bactericidal efficiency while reducing the associated side effects. Herein, amphiphilic antimicrobial copolymers derived from poly-l-lysine (PLL), black phosphorus quantum dots (BPQDs) as near-infrared (NIR) sensitizer, and S-nitrosocysteamine (SNO) as nitric oxide (NO) donor, are assembled into PELI@BPQD-SNO nanoparticles through electrostatic interactions. Amphiphilic copolymers with isopentanyl grafts on PLL at a ratio of 50% achieve an optimal balance between antibacterial activity and hemolysis rate. Photothermal effect of BPQDs leads to NIR-responsive release of NO and the combination with amphiphilic copolymers mutually enhances long-term inhibition of bacterial growth. In an S. aureus-infected subcutaneous abscess model, the bactericidal rate of PELI@BPQD-SNO/NIR treatment reaches nearly 99.6%, which is significantly higher than those without NO release (38%) or amphiphilic copolymers (24%) or NIR irradiation (17%). PELI@BPQD-SNO/NIR treatment shows full recovery of infected wounds, efficient retardation of inflammatory cells, and reconstruction of blood vessels similar to those of healthy skin. Therefore, the electrostatic assembly demonstrates a promising strategy to deliver charged therapeutic agents and the photoactivated release of NO and amphiphilic copolymers achieves synergistic antibacterial efficacy without using any antibiotics.

Thermo/glutathione-sensitive release kinetics of heterogeneous magnetic micro-organogel prepared by sono-catalysis

To improve the loading and delivery for hydrophobic drugs and optimize the release efficiency in tumor microenvironment, a novel core-shell magnetic micro-organogel carrier was successfully prepared by a sono-catalysis process in the study. As-synthesized magnetic micro-organogel had an appropriate dispersibility in water owing to the hydrophilicity of protein shell and could be kept steadily with a well-defined spherical morphology owing to the three-dimensional gel structure of oil core, and it promised an accessible targeted drug delivery owing to its good magnetism-mediated motion ability. Moreover, the magnetic micro-organogel showed a high loading efficiency up to 94.22% for coumarin 6 which was dissolved into the micro-organogel as a model hydrophobic drug. More importantly, the release kinetics revealed that the magnetic micro-organogel had a thermo-sensitive and glutathione (GSH)-sensitive ability to control the drug release, and proved that its release mechanisms referred to the combination of erosion, diffusion and degradation.

Tumor microenvironment remodeling-based penetration strategies to amplify nanodrug accessibility to tumor parenchyma

Remarkable advances in nano delivery systems have provided new hope for tumor prevention, diagnosis and treatment. However, only limited clinical therapeutic effects against solid tumors were achieved. One of the main reasons is the presence of abundant physiological and pathological barriers in vivo that impair tumoral penetration and distribution of the nanodrugs. These barriers are related to the components of tumor microenvironment (TME) including abnormal tumor vasculature, rich composition of the extracellular matrix (ECM), and abundant stroma cells. Herein, we review the advanced strategies of TME remodeling to overcome these biological obstacles against nanodrug delivery. This review aims to offer a perspective guideline for the implementation of promising approaches to facilitate intratumoral permeation of nanodrugs through alleviation of biological barriers. At the same time, we analyze the advantages and disadvantages of the corresponding methods and put forward possible directions for the future researches.

Recent progress in nanomedicine for enhanced cancer chemotherapy

As one of the most important cancer treatment strategies, conventional chemotherapy has substantial side effects and leads easily to cancer treatment failure. Therefore, exploring and developing more efficient methods to enhance cancer chemotherapy is an urgently important problem that must be solved. With the development of nanotechnology, nanomedicine has showed a good application prospect in improving cancer chemotherapy. In this review, we aim to present a discussion on the significant research progress in nanomedicine for enhanced cancer chemotherapy. First, increased enrichment of drugs in tumor tissues relying on different targeting ligands and promoting tissue penetration are summarized. Second, specific subcellular organelle-targeted chemotherapy is discussed. Next, different combinational strategies to reverse multidrug resistance (MDR) and improve the effective intracellular concentration of therapeutics are discussed. Furthermore, the advantages of combination therapy for cancer treatment are emphasized. Finally, we discuss the major problems facing therapeutic nanomedicine for cancer chemotherapy, and propose possible future directions in this field.

In Situ Modulating DNAzyme Activity and Internalization Behavior with Acid-Initiated Reconfigurable DNA Nanodevice for Activatable Theranostic

DNAzyme-mediated gene silencing was still challenged by off-target toxicity. In this study, we developed a split DNAzyme-based nanodevice (sDz-ND) that leveraged acidic tumor microenvironments to drive in situ assembly, thus modulating internalization behavior and silencing activity of DNAzymes. sDz-ND consisted of two different modules, which functionalized with split DNAzyme fragments, respectively. At psychological pH (∼7.4), the two modules were monodispersed, showing cleavage anergy and quenched fluorescence. At pH 6.3, the separated modules could cross-link with each other to form integrated sDz-ND, resulting activation of theranostic function. Meanwhile, the increased particle size and acquired multivalent effect favored 2.1-fold enhanced binding ability, which further facilitated rapid endocytosis of sDz-ND into target cancer cells, then allowing DNAzyme mediated gene silencing. The strategy provides a promising and general concept for precise tumor imaging and gene therapy.

A hybrid semiconducting organosilica-based O2 nanoeconomizer for on-demand synergistic photothermally boosted radiotherapy

The outcome of radiotherapy is significantly restricted by tumor hypoxia. To overcome this obstacle, one prevalent solution is to increase intratumoral oxygen supply. However, its effectiveness is often limited by the high metabolic demand for O₂ by cancer cells. Herein, we develop a hybrid semiconducting organosilica-based O₂ nanoeconomizer pHPFON-NO/O₂ to combat tumor hypoxia. Our solution is twofold: first, the pHPFON-NO/O₂ interacts with the acidic tumor microenvironment to release NO for endogenous O₂ conservation; second, it releases O₂ in response to mild photothermal effect to enable exogenous O₂ infusion. Additionally, the photothermal effect can be increased to eradicate tumor residues with radioresistant properties due to other factors. This “reducing expenditure of O₂ and broadening sources” strategy significantly alleviates tumor hypoxia in multiple ways, greatly enhances the efficacy of radiotherapy both in vitro and in vivo, and demonstrates the synergy between on-demand temperature-controlled photothermal and oxygen-elevated radiotherapy for complete tumor response.

Tumor hypoxia is a major limitation in radiotherapy, and strategies to address this often fail due to high oxygen consumption. Here, the authors report a nanomaterial assembly for the simultaneous reduction in mitochondrial respiration and to supply oxygen to potentiate radiotherapy.

Fighting Immune Cold and Reprogramming Immunosuppressive Tumor Microenvironment with Red Blood Cell Membrane-Camouflaged Nanobullets

Nanomedicine, acting as the magic bullet, is capable of combining immunotherapy with other treatments to reverse a cold tumor (immune depletion) into a hot tumor. However, how to comprehensively inhibit the immunosuppressive tumor microenvironment (TME) remains a major challenge for immunotherapy to achieve the maximum benefits. Thus, a strategy that can simultaneously increase the recruitment of tumor infiltrating lymphocytes (TILs) and comprehensively reprogram the immunosuppressive TME is still urgently needed. Herein, a thermal-sensitive nitric oxide (NO) donor S-nitrosothiols (SNO)-pendant copolymer (poly(acrylamide-co-acrylonitrile-co-vinylimidazole)-SNO copolymer, PAAV-SNO) with upper critical solution temperature (UCST) was synthesized and employed to fabricate an erythrocyte membrane-camouflaged nanobullet for codelivery of NIR II photothermal agent IR1061 and indoleamine 2,3-dioxygenase 1 (IDO-1) inhibitor 1-methyl-tryptophan (1-MT). This multifunctional nanobullet possessed long circulation in vivo, enhanced accumulation at the tumor site, and therapeutics-controlled release by NIR II laser, thereby it could avoid unspecific drug leakage while enhancing biosecurity. More importantly, the immunogenic cell death (ICD) induced by local hyperthermia from photothermal therapy (PTT) could be conducive for the increased recruitment of CD8+ cytotoxic T lymphocytes (CTLs) at the tumor site. Furthermore, through interfering in the IDO-1 activity by 1-MT and normalizing the tumor vessels by in situ generated NO, the immunosuppressive TME was comprehensively reprogrammed toward an immunostimulatory phenotype, achieving the excellent therapeutic efficacy against both primary breast cancer and metastases. Collectively, this multifunctional nanobullet described in this study developed an effective and promising strategy to comprehensively reprogram suppressive TME and treat "immune cold" tumors.

Biomimetic nano-NOS mediated local NO release for inhibiting cancer-associated platelet activation and disrupting tumor vascular barriers

Platelets attribute to the hypercoagulation of blood and maintenance of the tumor vascular integrity, resulting in limited intratumoral perfusion of nanoparticle into solid tumors. To overcome these adversities, we herein present an antiplatelet strategy based on erythrocyte membrane-enveloped proteinic nanoparticles that biomimic nitric oxide synthase (NOS)with co-loading of l-Arginine (LA) and photosensitizer IR783 for local NO release and inhibition of the activation of tumor-associated platelets specifically, thereby enhancing vascular permeability and accumulation of the nanoparticles in tumors. A cRGD-immobolized membrane structure is constructed to actively target platelets and cancer cells respectively, through overexpressed integrin receptors such as integrin α_IIbβ₃ and α_vβ₃, accelerating the inhibition of platelet activation and endocytosis of nanoparticles by tumor cells. Bio-mimicking the arginine/NO pathway in vivo, synergistical delivery of LA and IR783 enables LA molecules readily oxidize to NO with O₂ that is mediated by activated IR783, the resulted NO not only retards the activity of platelets to disrupt the vascular integrity of tumor but also enhances toxicity to cancer cells. In addition, NIR-controlled release localizes the NO spatiotemporally to tumor-associated platelets and prevents undesirable systemic bleeding substantially. The reduction of the hypercoagulable state is further demonstrated by the down-regulation of tissues factor (TF) expression in tumor cells. Our study describes a promising approach to combat cancer, which advances the biomimetic NOS system as the potent therapeutic forces toward clinic applications.

Enhanced nanoparticle accumulation by tumor-acidity-activatable release of sildenafil to induce vasodilation

Inefficient nanoparticle accumulation in solid tumors hinders the clinical translation of cancer nanomedicines. Herein, we proposed that sildenafil, a vasodilator ampholyte, could be used to promote nanoparticle accumulation by inducing vasodilation after its tumor acidity-triggered release from the nanocarriers. To confirm this, sildenafil was first encapsulated in a cisplatin-incorporated polymeric micelle. The dense PEG shell of the micelle reduced its endocytosis by cancer cells, which in return resulted in accumulative extracellular release of protonated sildenafil in the acidic tumor microenvironment. The released sildenafil was found to be more effective in enlarging the tumor blood vessels than could be achieved without sildenafil. As a result, we demonstrated considerable improvement in the intratumoral accumulation of the sildenafil-cisplatin co-loaded nanoparticle and its enhanced cancer therapeutic efficacy over the control group. Given the generality of a dense PEG shell and a hydrophobic part in most clinically developed nanomedicines, this work implies the great potential of sildenafil as a simple and universal adjuvant to selectively promote the intratumoral accumulation of nanomedicines, thus improving their clinical translation.

Hyperthermia can alter tumor physiology and improve chemo- and radio-therapy efficacy

Hyperthermia has demonstrated clinical success in improving the efficacy of both chemo- and radio-therapy in solid tumors. Pre-clinical and clinical research studies have demonstrated that targeted hyperthermia can increase tumor blood flow and increase the perfused fraction of the tumor in a temperature and time dependent manner. Changes in tumor blood circulation can produce significant physiological changes including enhanced vascular permeability, increased oxygenation, decreased interstitial fluid pressure, and reestablishment of normal physiological pH conditions. These alterations in tumor physiology can positively impact both small molecule and nanomedicine chemotherapy accumulation and distribution within the tumor, as well as the fraction of the tumor susceptible to radiation therapy. Hyperthermia can trigger drug release from thermosensitive formulations and further improve the accumulation, distribution, and efficacy of chemotherapy.

Incorporation of drug efflux inhibitor and chemotherapeutic agent into an inorganic/organic platform for the effective treatment of multidrug resistant breast cancer

BACKGROUND

Multidrug resistance (MDR) is a pressing obstacle in clinical chemotherapy for breast cancer. Based on the fact that the drug efflux is an important factor in MDR, we designed a codelivery system to guide the drug efflux inhibitor verapamil (VRP) and the chemotherapeutic agent novantrone (NVT) synergistically into breast cancer cells to reverse MDR.

RESULTS

This co-delivery system consists of following components: the active targeting peptide RGD, an inorganic calcium phosphate (CaP) shell and an organic inner core. VRP and NVT were loaded into CaP shell and phosphatidylserine polyethylene glycol (PS-PEG) core of nanoparticles (NPs) separately to obtain NVT- and VRP-loaded NPs (NV@CaP-RGD). These codelivered NPs allowed VRP to prevent the efflux of NVT from breast cancer cells by competitively combining with drug efflux pumps. Additionally, NV@CaP-RGD was effectively internalized into breast cancer cells by precise delivery through the effects of the active targeting peptides RGD and EPR. The pH-triggered profile of CaP was also able to assist the NPs to successfully escape from lysosomes, leading to a greatly increased effective intracellular drug concentration.

CONCLUSION

The concurrent administration of VRP and NVT by organic/inorganic NPs is a promising therapeutic approach to reverse MDR in breast cancer.

Nanomaterial-Based Modulation of Tumor Microenvironments for Enhancing Chemo/Immunotherapy

The tumor microenvironment (TME) has drawn considerable research attention as an alternative target for nanomedicine-based cancer therapy. Various nanomaterials that carry active substances have been designed to alter the features or composition of the TME and thereby improve the delivery and efficacy of anticancer chemotherapeutics. These alterations include disruption of the extracellular matrix and tumor vascular systems to promote perfusion or modulate hypoxia. Nanomaterials have also been used to modulate the immunological microenvironment of tumors. In this context, nanomaterials have been shown to alter populations of cancer-associated fibroblasts, tumor-associated macrophages, regulatory T cells, and myeloid-derived suppressor cells. Despite considerable progress, nanomaterial-based TME modulation must overcome several limitations before this strategy can be translated to clinical trials, including issues related to limited tumor tissue penetration, tumor heterogeneity, and immune toxicity. In this review, we summarize recent progress and challenges of nanomaterials used to modulate the TME to enhance the efficacy of anticancer chemotherapy and immunotherapy.