A Dual-Bioresponsive Drug-Delivery Depot for Combination of Epigenetic Modulation and Immune Checkpoint Blockade

Immune checkpoint blocking in cancer therapy using thermosensitive hydrogels: a review

Cancer is a challenging issue requiring new strategies for management and control. Immune checkpoint blockades (ICBs) increase the body's immune response against cancer by targeting specific receptors on T-lymphocytes. The FDA approved different ICBs for cancer treatment: anti-PD-1, PDL-1, and CTLA-4 inhibitors. Many immune checkpoint inhibitors (ICIs) are in clinical trials, highlighting their significance. Challenges like resistance and side effects have led researchers to explore new delivery strategies for ICIs. Thermosensitive hydrogels can change from sol to gel and vice versa due to their structure. They interact with aqueous medium through groups like ethyl, methyl, and propyl, forming hydrogen bonds. These bonds of hydrogen are temperature-sensitive and cause the change of the polymer from sol to gel at a temperature named critical solution temperature (CST). The using temperature-responsive polymers and ICBs showed a promising approach to sustained localized cancer therapy with lowering side effects on normal tissues. In this paper, we first define new investigations on immune therapy in cancer via ICBs. Then, we present recent studies of thermosensitive polymers in cancer therapy and the most used thermosensitive polymers in studies. Eventually, we discuss studies that used thermosensitive polymers in the delivery of ICBs and discuss new investigations in this field.

Immunogenic Cell Death and Metabolic Reprogramming in Cancer: Mechanisms, Synergies, and Innovative Therapeutic Strategies

Immunogenic cell death (ICD) is a promising cancer therapy where dying tumor cells release damage-associated molecular patterns (DAMPs) to activate immune responses. Recent research highlights the critical role of metabolic reprogramming in tumor cells, including the Warburg effect, oxidative stress, and lipid metabolism, in modulating ICD and shaping the immune microenvironment. These metabolic changes enhance immune activation, making tumors more susceptible to immune surveillance. This review explores the molecular mechanisms linking ICD and metabolism, including mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, and ferroptosis. It also discusses innovative therapeutic strategies, such as personalized combination therapies, metabolic inhibitors, and targeted delivery systems, to improve ICD efficacy. The future of cancer immunotherapy lies in integrating metabolic reprogramming and immune activation to overcome tumor immune evasion, with multi-omics approaches and microbiome modulation offering new avenues for enhanced treatment outcomes.

Enhancing immunotherapy with tumour-responsive nanomaterials

The targeted delivery of immunotherapies to tumours using tumour-responsive nanomaterials is a promising area of cancer research with the potential to address the limitations of systemic administration such as on-target off-tumour toxicities and a lack of activity owing to the immunosuppressive tumour microenvironment (TME). Attempts to address these challenges include the design and functionalization of nanomaterials capable of releasing their cargoes in response to specific TME characteristics, thus facilitating the targeted delivery of immune-checkpoint inhibitors, cytokines, mRNAs, vaccines and, potentially, chimaeric antigen receptors as well as of agents that modulate the extracellular matrix and induce immunogenic cell death. In this Review, we describe these various research efforts in the context of the dynamic properties of the TME, such as pH, reductive conditions, reactive oxygen species, hypoxia, specific enzymes, high levels of ATP and locoregional aspects, which can be leveraged to enhance the specificity and efficacy of nanomaterial-based immunotherapies. Highlighting preclinical successes and ongoing clinical trials, we evaluate the current landscape and potential of these innovative approaches. We also consider future research directions as well as the most important barriers to successful clinical translation, emphasizing the transformative potential of tumour-responsive nanomaterials in overcoming the barriers that limit the activity of traditional immunotherapies, thus improving patient outcomes.

Extracellular Vesicles for Disease Treatment

Traditional drug therapies suffer from problems such as easy drug degradation, side effects, and treatment resistance. Traditional disease diagnosis also suffers from high error rates and late diagnosis. Extracellular vesicles (EVs) are nanoscale spherical lipid bilayer vesicles secreted by cells that carry various biologically active components and are integral to intercellular communication. EVs can be found in different body fluids and may reflect the state of the parental cells, making them ideal noninvasive biomarkers for disease-specific diagnosis. The multifaceted characteristics of EVs render them optimal candidates for drug delivery vehicles, with evidence suggesting their efficacy in the treatment of various ailments. However, poor stability and easy degradation of natural EVs have affected their applications. To solve the problems of poor stability and easy degradation of natural EVs, they can be engineered and modified to obtain more stable and multifunctional EVs. In this study, we review the shortcomings of traditional drug delivery methods and describe how to modify EVs to form engineered EVs to improve their utilization. An innovative stimulus-responsive drug delivery system for EVs has also been proposed. We also summarize the current applications and research status of EVs in the diagnosis and treatment of different systemic diseases, and look forward to future research directions, providing research ideas for scholars.

Clinicopathological characteristics of invasive stratified mucinous carcinoma of the cervix and the expression and clinical significance of SLC7A11, SLC3A2 and PD-L1

Introduction

Invasive Stratified Mucin-producing Carcinoma (ISMC) of the cervix is a newly named cervical adenocarcinoma associated with Human Papilloma virus (HPV). Due to its relative rarity, clinical data, pathological features, and molecular characteristics of ISMC are still under exploration. This study aims to retrospectively analyze the clinical data and pathological features of ISMC patients, summarizing the clinical and pathological morphological characteristics of ISMC. Immunohistochemistry for SLC7A11, SLC3A2, and PD-L1 will be performed on tumor tissues from ISMC patients to preliminarily explore potential therapeutic targets for ISMC.

Methods

We retrospectively reviewed the electronic medical records and pathological slides of 22 ISMC patients, and performed immunohistochemical staining for solute carrier family 7 member 11 (SLC7A11), solute carrier family 3 member 2 (SLC3A2), and programmed death-ligand 1 (PD-L1).

Results

The patients were aged between 31 and 70 years old. The most common symptoms were abnormal vaginal bleeding and unusual vaginal discharge. HPV testing indicated that the infection rate of HPV type 18 was the highest. All patients underwent extensive hysterectomy and pelvic lymph node dissection. The progression-free survival (PFS) ranged from 3 to 112 months, with a postoperative recurrence rate of 22.7% (5/22). ISMC exhibited diverse characteristic microstructures. Immunohistochemistry results showed that the positive rates of SLC7A11 and SLC3A2 were both 91.0% (20/22). The staining intensity of SLC7A11 in frequent ISMC recurrence cases was significantly stronger than in non-recurrent ISMC cases. PD-L1 positivity was observed in 86.4% (19/22) of cases, defined as having a Combined Positive Score(CPS)≥1.

Discussion

ISMC demonstrates a high rate of lymph node metastasis and a high recurrence rate, indicating strong invasiveness. Additionally, ISMC exhibits a wide morphological spectrum. SLC7A11, SLC3A2, and PD-L1 are all highly expressed in ISMC tissues. The high expression of SLC7A11 may indicate a high recurrence rate for ISMC. Immunotherapy with checkpoint inhibitors and iron death-related treatments show potential in the treatment of ISMC, with SLC7A11, SLC3A2, and PD-L1 serving as potential therapeutic targets for ISMC.

Injectable Polydopamine Nanoparticle-Incorporated Hydrogels for Antiangiogenesis and Stimulating Tumoricidal Immunity to Inhibit Metastasis and Recurrence Postresection

Surgical resection is still the main means for clinical treatments of breast cancer, but the postoperative immunosuppressive microenvironment and neoangiogenesis of the residual tumors easily lead to tumor metastasis and recurrence, which will further endanger patients' lives. The combination of antiangiogenic therapy and immunotherapy may promote the mutually reinforced cycle of immune reprogramming and vascular normalization to avoid tumor metastasis and recurrence. Herein, we prepared polydopamine nanoparticles for improving tissue adhesion and enriching tumor-associated antigens. This nanoregulator together with regorafenib (REG) was further incorporated into a hydrogel developed from grafting adipic acid dihydrazide onto 2,2,6,6-tetramethylpiperidine-1-oxyl radical oxidized chitin and oxidized hyaluronic acid, which was injectable at the cavity after subcutaneous tumor surgery with good mechanical properties and degradability. The system showed long-term release of REG. After combining with anti-PD-L1, the hydrogel applied to the surgical wound exhibited a reduction in tumor metastasis and recurrence. This effect was achieved by suppressing angiogenesis and enhancing antitumor immunity, characterized by increased levels of effector T lymphocytes and activation of dendritic cells within tumors, spleens, and draining lymph nodes. The injectable hydrogel offers a promising strategy for postoperative management aimed at preventing tumor metastasis and recurrence.

Emerging Strategies for Local Delivery of Immune Checkpoint Inhibitors to Potentiate Cancer Immunotherapy: Current Status and Future Prospects

Cancer constitutes a significant threat to patients' lives worldwide. Immunotherapy, particularly immune checkpoint inhibitors (ICIs) that boost antitumor immunity by targeting immune checkpoint components, has emerged as a promising strategy for its treatment in recent years. However, the objective response rates of the ICIs are unsatisfactory. As the primary route, systemic administration of ICIs is often accompanied by immune-related adverse events. Local delivery of ICIs serves as a potential therapeutic strategy that can improve the efficacy while simultaneously reducing side effects through precise drug release at the tumor site. Initial validation of direct local application of ICIs for tumors in clinical trials has indicated reduced side effects and improved efficacy, while low bioavailability remains a challenge. Furthermore, research on various carriers, including nanoparticles, microneedles, hydrogels, combined platforms, and implantable devices for local release of ICIs has exhibited applying potential in treating murine tumors, among which combined platforms such as combined hydrogel system hold the highest promise due to their encompassment of the advantages of multiple carriers. These carriers, by incorporating ICIs and other therapeutics, could manage cancers more potently, which needs to be confirmed in clinical trials after the refinement of their biocompatibility. This review summarizes the latest research advancements regarding local administration of ICIs, with a particular focus on the carriers for local delivery as well as the combination therapies, thus providing novel insights and research guidance for scholars to enhance the efficacy of locally delivered ICIs on managing multiple cancers in the future.

Epigenetic frontiers: miRNAs, long non-coding RNAs and nanomaterials are pioneering to cancer therapy

Cancer has arisen from both genetic mutations and epigenetic changes, making epigenetics a crucial area of research for innovative cancer prevention and treatment strategies. This dual perspective has propelled epigenetics into the forefront of cancer research. This review highlights the important roles of DNA methylation, histone modifications and non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long non-coding RNAs, which are key regulators of cancer-related gene expression. It explores the potential of epigenetic-based therapies to revolutionize patient outcomes by selectively modulating specific epigenetic markers involved in tumorigenesis. The review examines promising epigenetic biomarkers for early cancer detection and prognosis. It also highlights recent progress in oligonucleotide-based therapies, including antisense oligonucleotides (ASOs) and antimiRs, to precisely modulate epigenetic processes. Furthermore, the concept of epigenetic editing is discussed, providing insight into the future role of precision medicine for cancer patients. The integration of nanomedicine into cancer therapy has been explored and offers innovative approaches to improve therapeutic efficacy. This comprehensive review of recent advances in epigenetic-based cancer therapy seeks to advance the field of precision oncology, ultimately culminating in improved patient outcomes in the fight against cancer.

Intelligent Hydrogel-Assisted Hepatocellular Carcinoma Therapy

Given the high malignancy of liver cancer and the liver's unique role in immune and metabolic regulation, current treatments have limited efficacy, resulting in a poor prognosis. Hydrogels, soft 3-dimensional network materials comprising numerous hydrophilic monomers, have considerable potential as intelligent drug delivery systems for liver cancer treatment. The advantages of hydrogels include their versatile delivery modalities, precision targeting, intelligent stimulus response, controlled drug release, high drug loading capacity, excellent slow-release capabilities, and substantial potential as carriers of bioactive molecules. This review presents an in-depth examination of hydrogel-assisted advanced therapies for hepatocellular carcinoma, encompassing small-molecule drug therapy, immunotherapy, gene therapy, and the utilization of other biologics. Furthermore, it examines the integration of hydrogels with conventional liver cancer therapies, including radiation, interventional therapy, and ultrasound. This review provides a comprehensive overview of the numerous advantages of hydrogels and their potential to enhance therapeutic efficacy, targeting, and drug delivery safety. In conclusion, this review addresses the clinical implementation of hydrogels in liver cancer therapy and future challenges and design principles for hydrogel-based systems, and proposes novel research directions and strategies.

STING Agonist Delivered by Neutrophil Membrane-Coated Gold Nanoparticles Exerts Synergistic Tumor Inhibition with Radiotherapy

Radiotherapy (RT) is one of the major treatments for cancers and a promising initiator of immune response. Gold nanoparticles are a promising radiosensitizer. In this study, we sought to optimize the drug delivery efficiency of gold nanoparticles and explore their function in delivering stimulator of interferon genes (STING) agonists with or without RT. Gold nanoparticles covalent to MSA-2 (MSA-Au) were mixed with cRGD-modified neutrophil membranes to obtain M-Au@RGD-NM. We explored the treatment efficiency of M-Au@RGD-NM combined with RT. Immune cell regulation and STING pathway activation were detected. We successfully prepared M-Au@RGD-NM with significant tumor suppression by induction of ROS and the resulting DNA damage. In vivo dynamic imaging showed that M-Au@RGD-NM was mainly targeted to radiated tumors. Tumor-bearing mice showed significant tumor inhibition following a combination therapy. M-Au@RGD-NM significantly activated the STING pathway and regulated the whole-body immune response. Locally radiated tumors showed dendritic cells mature, CD8+ T cells upregulation, and M1 polarization, with systematic immune response demonstrated by CD8+ T cell infiltration in abscopal tumors. In this study, we synthesized M-Au@RGD-NM loading MSA-2. Following characterization, we found that RT-based M-Au@RGD-NM treatment achieved good antitumor effects, tumor RT enhancement, and induction of an immune response via STING activation.

Hydrogels as a Potential Biomaterial for Multimodal Therapeutic Applications

Hydrogels, composed of hydrophilic polymer networks, have emerged as versatile materials in biomedical applications due to their high water content, biocompatibility, and tunable properties. They mimic natural tissue environments, enhancing cell viability and function. Hydrogels' tunable physical properties allow for tailored antibacterial biomaterial, wound dressings, cancer treatment, and tissue engineering scaffolds. Their ability to respond to physiological stimuli enables the controlled release of therapeutics, while their porous structure supports nutrient diffusion and waste removal, fostering tissue regeneration and repair. In wound healing, hydrogels provide a moist environment, promote cell migration, and deliver bioactive agents and antibiotics, enhancing the healing process. For cancer therapy, they offer localized drug delivery systems that target tumors, minimizing systemic toxicity and improving therapeutic efficacy. Ocular therapy benefits from hydrogels' capacity to form contact lenses and drug delivery systems that maintain prolonged contact with the eye surface, improving treatment outcomes for various eye diseases. In mucosal delivery, hydrogels facilitate the administration of therapeutics across mucosal barriers, ensuring sustained release and the improved bioavailability of drugs. Tissue regeneration sees hydrogels as scaffolds that mimic the extracellular matrix, supporting cell growth and differentiation for repairing damaged tissues. Similarly, in bone regeneration, hydrogels loaded with growth factors and stem cells promote osteogenesis and accelerate bone healing. This article highlights some of the recent advances in the use of hydrogels for various biomedical applications, driven by their ability to be engineered for specific therapeutic needs and their interactive properties with biological tissues.

Imaging-Based Efficacy Evaluation of Cancer Immunotherapy in Engineered Tumor Platforms and Tumor Organoids

Cancer immunotherapy is used to treat tumors by modulating the immune system. Although the anticancer efficacy of cancer immunotherapy has been evaluated prior to clinical trials, conventional in vivo animal and endpoint models inadequately replicate the intricate process of tumor elimination and reflect human-specific immune systems. Therefore, more sophisticated models that mimic the complex tumor-immune microenvironment must be employed to assess the effectiveness of immunotherapy. Additionally, using real-time imaging technology, a step-by-step evaluation can be applied, allowing for a more precise assessment of treatment efficacy. Here, an overview of the various imaging-based evaluation platforms recently developed for cancer immunotherapeutic applications is presented. Specifically, a fundamental technique is discussed for stably observing immune cell-based tumor cell killing using direct imaging, a microwell that reproduces a confined space for spatial observation, a droplet assay that facilitates cell-cell interactions, and a 3D microphysiological system that reconstructs the vascular environment. Furthermore, it is suggested that future evaluation platforms pursue more human-like immune systems.

Tumor microenvironment-responsive manganese-based nano-modulator activate the cGAS-STING pathway to enhance innate immune system response

BACKGROUND

Manganese ions (Mn2+) combined with adjuvants capable of damaging and lysing tumor cells form an antitumor nano-modulator that enhances the immune efficacy of cancer therapy through the cascade activation of the cyclic GMP-AMP interferon gene synthase-stimulator (cGAS-STING) pathway, which underscores the importance of developing antitumor nano-modulators, which induce DNA damage and augment cGAS-STING activity, as a critical future research direction. METHODS AND RESULTS: We have successfully synthesized an antitumor nano-modulator, which exhibits good dispersibility and biosafety. This nano-modulator is engineered by loading manganese dioxide nanosheets (M-NS) with zebularine (Zeb), known for its immunogenicity-enhancing effects, and conducting targeted surface modification using hyaluronic acid (HA). After systemic circulation to the tumor site, Mn2+, Zeb, and reactive oxygen species (ROS) are catalytically released in the tumor microenvironment by H+ and H2O2. These components can directly or indirectly damage the DNA or mitochondria of tumor cells, thereby inducing programmed cell death. Furthermore, they promote the accumulation of double-stranded DNA (dsDNA) in the cytoplasm, enhancing the activation of the cGAS-STING signalling pathway and boosting the production of type I interferon and the secretion of pro-inflammatory cytokines. Additionally, Zeb@MH-NS enhances the maturation of dendritic cells, the infiltration of cytotoxic T lymphocytes, and the recruitment of natural killer cells at the tumor site.

CONCLUSIONS

This HA-modified manganese-based hybrid nano-regulator can enhance antitumor therapy by boosting innate immune activity and may provide new directions for immunotherapy and clinical translation in cancer.

Wrecking neutrophil extracellular traps and antagonizing cancer-associated neurotransmitters by interpenetrating network hydrogels prevent postsurgical cancer relapse and metastases

Tumor-promoting niche after incomplete surgery resection (SR) can lead to more aggressive local progression and distant metastasis with augmented angiogenesis-immunosuppressive tumor microenvironment (TME). Herein, elevated neutrophil extracellular traps (NETs) and cancer-associated neurotransmitters (CANTs, e.g., catecholamines) are firstly identified as two of the dominant inducements. Further, an injectable fibrin-alginate hydrogel with high tissue adhesion has been constructed to specifically co-deliver NETs inhibitor (DNase I)-encapsulated PLGA nanoparticles and an unselective β-adrenergic receptor blocker (propranolol). The two components (i.e., fibrin and alginate) can respond to two triggers (thrombin and Ca2+, respectively) in postoperative bleeding to gelate, shaping into an interpenetrating network (IPN) featuring high strength. The continuous release of DNase I and PR can wreck NETs and antagonize catecholamines to decrease microvessel density, blockade myeloid-derived suppressor cells, secrete various proinflammatory cytokines, potentiate natural killer cell function and hamper cytotoxic T cell exhaustion. The reprogrammed TME significantly suppress locally residual and distant tumors, induce strong immune memory effects and thus inhibit lung metastasis. Thus, targetedly degrading NETs and blocking CANTs enabled by this in-situ IPN-based hydrogel drug depot provides a simple and efficient approach against SR-induced cancer recurrence and metastasis.

Two-pronged anti-cancer nanovaccines enpowered by exogenous/endogenous tumor-associated antigens

Cancer vaccines based on single-source (exogenous or endogenous) tumor-associated antigens (TAAs) are often challenged by the insufficient T cell response and the immunosuppressive tumor microenvironment (TME). Herein, a dual TAAs-boosted nanovaccine based on cancer cell (4T1) membrane-cloaked, CO-immobilized Prussian blue nanoparticles (4T1-PB-CO NPs) is developed and coupled with anti-interleukin (IL)-10 therapy to maximize the efficacy of antitumor immunotherapy. 4T1 cell membrane not only endows NPs with tumor targeting ability, but also serves as exogenous TAAs to trigger CD4+ T cell response and M1-phenotype polarization of tumor-associated macrophages. Under near-infrared light irradiation, 4T1-PB-CO NPs release CO to induce immunogenic cell death (ICD) of tumor cells, thus generating endogenous TAAs to activate CD8+ T cell response. Meanwhile, ICD triggers release of damage-associated molecular patterns, which can promote DC maturation to amplify the antitumor T cell response. When combined with anti-IL-10 that reverses the immunosuppressive TME, 4T1-PB-CO NPs efficiently suppress the primary tumors and produce an abscopal effect to inhibit distant tumors in a breast tumor-bearing mouse model. Such a two-pronged cancer vaccine represents a promising paradigm for robust antitumor immunotherapy.

Enhancing in situ cancer vaccines using delivery technologies

In situ cancer vaccination refers to any approach that exploits tumour antigens available at a tumour site to induce tumour-specific adaptive immune responses. These approaches hold great promise for the treatment of many solid tumours, with numerous candidate drugs under preclinical or clinical evaluation and several products already approved. However, there are challenges in the development of effective in situ cancer vaccines. For example, inadequate release of tumour antigens from tumour cells limits antigen uptake by immune cells; insufficient antigen processing by antigen-presenting cells restricts the generation of antigen-specific T cell responses; and the suppressive immune microenvironment of the tumour leads to exhaustion and death of effector cells. Rationally designed delivery technologies such as lipid nanoparticles, hydrogels, scaffolds and polymeric nanoparticles are uniquely suited to overcome these challenges through the targeted delivery of therapeutics to tumour cells, immune cells or the extracellular matrix. Here, we discuss delivery technologies that have the potential to reduce various clinical barriers for in situ cancer vaccines. We also provide our perspective on this emerging field that lies at the interface of cancer vaccine biology and delivery technologies.

Overcoming T Cell Exhaustion in Tumor Microenvironment via Immune Checkpoint Modulation with Nano-Delivery Systems for Enhanced Immunotherapy

Immune checkpoint blockade (ICB) therapy for tumors has arisen in growing interest. However, the low response rate of tumors to ICB is mainly attributed to the inhibitory infiltration of immune cells in the tumor microenvironment (TME). Despite the promising benefits of ICB, the therapeutic effects of antibodies are dependent on a high dose and long-term usage in the clinic, thereby leading to immune-related adverse effects. Accordingly, ICB combined with nano-delivery systems could be used to overcome T cell exhaustion, which reduces the side effects and the usage of antibodies with higher response rates in patients. In this review, the authors aim to overcome T cell exhaustion in TME via immune checkpoint modulation with nano-delivery systems for enhanced immunotherapy. Several strategies are summarized to combine ICB and nano-delivery systems to further enhance immunotherapy: a) expressing immune checkpoint on the surface of nano-delivery systems; b) loading immune checkpoint inhibitors into nano-delivery systems; c) loading gene-editing technology into nano-delivery systems; and d) nano-delivery systems mediated immune checkpoint modulation. Taken together, ICB combined with nano-delivery systems might be a promising strategy to overcome T cell exhaustion in TME for enhanced immunotherapy.

Ultrasound-Activatable In Situ Vaccine for Enhanced Antigen Self- and Cross-Presentation to Overcome Cancer Immunotherapy Resistance

Insufficient antigen self-presentation of tumor cells and ineffective antigen cross-presentation by dendritic cells (DCs) contribute to diminished immune recognition and activation, which cause resistance to immunotherapies. Herein, we present an ultrasound-activatable in situ vaccine by utilizing a hybrid nanovesicle composed of a thylakoid (TK)/platelet (PLT) membrane and a liposome encapsulating DNA methyltransferase inhibitor zebularine (Zeb) and sonosensitizer hematoporphyrin monomethyl ether (HMME). Upon local exposure to ultrasound, reactive oxygen species (ROS) are generated and induce the sequential release of the payloads. Zeb can efficiently inhibit tumor DNA hypermethylation, promoting major histocompatibility complex class I (MHC-I) molecules-mediated antigen self-presentation to improve immune recognition. Meanwhile, the catalase on the TK membrane can decompose the tumoral overexpressed H2O2 into O2, which boosts the generation of ROS and the destruction of tumor cells, resulting in the in situ antigen release and cross-presentation of tumor antigens by DCs. This in situ vaccine simultaneously promotes antigen self-presentation and cross-presentation, resulting in heightened antitumor immunity to overcome resistance.

A Hydrogen-Bonded Organic Framework-Based Mitochondrion-Targeting Bioorthogonal Platform for the Modulation of Mitochondrial Epigenetics

Bioorthogonal chemistry represents a powerful tool in chemical biology, which shows great potential in epigenetic modulation. As a proof of concept, the epigenetic modulation model of mitochondrial DNA (mtDNA) is selected because mtDNA establishes a relative hypermethylation stage under oxidative stress, which impairs the mitochondrion-based therapeutic effect during cancer therapy. Herein, we design a new biocompatible hydrogen-bonded organic framework (HOF) for a HOF-based mitochondrion-targeting bioorthogonal platform TPP@P@PHOF-2. PHOF-2 can activate a prodrug (pro-procainamide) in situ, which can specifically inhibit DNA methyltransferase 1 (DNMT1) activity and remodel the epigenetic modification of mtDNA, making it more susceptible to ROS damage. In addition, PHOF-2 can also catalyze artemisinin to produce large amounts of ROS, effectively damaging mtDNA and achieving better chemodynamic therapy demonstrated by both in vitro and in vivo studies. This work provides new insights into developing advanced bioorthogonal therapy and expands the applications of HOF and bioorthogonal catalysis.

Injectable Nanocomposite Hydrogels Improve Intraperitoneal Co-delivery of Chemotherapeutics and Immune Checkpoint Inhibitors for Enhanced Peritoneal Metastasis Therapy

Intraperitoneal co-delivery of chemotherapeutic drugs (CDs) and immune checkpoint inhibitors (ICIs) brings hope to improve treatment outcomes in patients with peritoneal metastasis from ovarian cancer (OC). However, current intraperitoneal drug delivery systems face issues such as rapid drug clearance from lymphatic drainage, heterogeneous drug distribution, and uncontrolled release of therapeutic agents into the peritoneal cavity. Herein, we developed an injectable nanohydrogel by combining carboxymethyl chitosan (CMCS) with bioadhesive nanoparticles (BNPs) based on polylactic acid-hyperbranched polyglycerol. This system enables the codelivery of CD and ICI into the intraperitoneal space to extend drug retention. The nanohydrogel is formed by cross-linking of aldehyde groups on BNPs with amine groups on CMCS via reversible Schiff base bonds, with CD and ICI loaded separately into BNPs and CMCS network. BNP/CMCS nanohydrogel maintained the activity of the biomolecules and released drugs in a sustained manner over a 7 day period. The adhesive property, through the formation of Schiff bases with peritoneal tissues, confers BNPs with an extended residence time in the peritoneal cavity after being released from the nanohydrogel. In a mouse model, BNP/CMCS nanohydrogel loaded with paclitaxel (PTX) and anti-PD-1 antibodies (αPD-1) significantly suppressed peritoneal metastasis of OC compared to all other tested groups. In addition, no systemic toxicity of nanohydrogel-loaded PTX and αPD-1 was observed during the treatment, which supports potential translational applications of this delivery system.

Biomaterials-assisted cancer vaccine delivery: preclinical landscape, challenges, and opportunities

INTRODUCTION

Cancer vaccines (protein and peptide, DNA, mRNA, and tumor cell) have achieved remarkable success in the treatment of cancer. In particular, advances in the design and manufacture of biomaterials have made it possible to control the presentation and delivery of vaccine components to immune cells.

AREAS COVERED

This review summarizes findings from major databases, including PubMed, Scopus, and Web of Science, focusing on articles published between 2005 and 2024 that discuss biomaterials in cancer vaccine delivery.

EXPERT OPINION

The development of cancer vaccines is hindered by several bottlenecks, including low immunogenicity, instability of vaccine components, and challenges in evaluating their clinical efficacy. To transform preclinical successes into viable treatments, it is essential to pursue continued innovation, collaborative research, and address issues related to scalability, regulatory pathways, and clinical validation, ultimately improving outcomes against cancer.

Oral biomimetic virus vaccine hydrogel for robust abscopal antitumour efficacy

Remarkable progress has been made in tumour immunotherapy in recent decades. However, the clinical outcomes of therapeutic interventions remain unpredictable, largely because of inefficient immune responses. To address this challenge and optimise immune stimulation, we present a novel administration route for enhancing the bioavailability of immunotherapeutic drugs. Our approach involves the development of an oral tumour vaccine utilising virus-like particles derived from the Hepatitis B virus core (HBc) antigen. The external surfaces of these particles are engineered to display the model tumour antigen OVA, whereas the interiors are loaded with cytosine phosphoguanosine oligodeoxynucleotide (CpG ODN), resulting in a construct called CpG@OVAHBc with enhanced antigenicity and immune response. For oral delivery, CpG@OVAHBc is encapsulated in a crosslinked dextran hydrogel called CpG@OVAHBc@Dex. The external hydrogel shield safeguards the biomimetic virus particles from degradation by gastric acid and proteases. Upon exposure to intestinal flora, the hydrogel disintegrates, releasing CpG@OVAHBc at the intestinal mucosal site. Owing to its virus-like structure, CpG@OVAHBc exhibits enhanced adhesion to the mucosal surface, facilitating uptake by microfold cells (M cells) and subsequent transmission to antigen-presenting cells. The enzyme-triggered release of this oral hydrogel ensures the integrity of the tumour vaccine within the digestive tract, allowing targeted release and significantly improving bioavailability. Beyond its efficacy, this oral hydrogel vaccine streamlines drug administration, alleviates patient discomfort, and enhances treatment compliance without the need for specialised injection methods. Consequently, our approach expands the horizons of vaccine development in the field of oral drug administration.

Engineered Bio-Based Hydrogels for Cancer Immunotherapy

Immunotherapy represents a revolutionary paradigm in cancer management, showcasing its potential to impede tumor metastasis and recurrence. Nonetheless, challenges including limited therapeutic efficacy and severe immune-related side effects are frequently encountered, especially in solid tumors. Hydrogels, a class of versatile materials featuring well-hydrated structures widely used in biomedicine, offer a promising platform for encapsulating and releasing small molecule drugs, biomacromolecules, and cells in a controlled manner. Immunomodulatory hydrogels present a unique capability for augmenting immune activation and mitigating systemic toxicity through encapsulation of multiple components and localized administration. Notably, hydrogels based on biopolymers have gained significant interest owing to their biocompatibility, environmental friendliness, and ease of production. This review delves into the recent advances in bio-based hydrogels in cancer immunotherapy and synergistic combinatorial approaches, highlighting their diverse applications. It is anticipated that this review will guide the rational design of hydrogels in the field of cancer immunotherapy, fostering clinical translation and ultimately benefiting patients.

CaCO3 nanoplatform for cancer treatment: drug delivery and combination therapy

The use of nanocarriers for drug delivery has opened up exciting new possibilities in cancer treatment. Among them, calcium carbonate (CaCO3) nanocarriers have emerged as a promising platform due to their exceptional biocompatibility, biosafety, cost-effectiveness, wide availability, and pH-responsiveness. These nanocarriers can efficiently encapsulate a variety of small-molecule drugs, proteins, and nucleic acids, as well as co-encapsulate multiple drugs, providing targeted and sustained drug release with minimal side effects. However, the effectiveness of single-drug therapy using CaCO3 nanocarriers is limited by factors such as multidrug resistance, tumor metastasis, and recurrence. Combination therapy, which integrates multiple treatment modalities, offers a promising approach for tackling these challenges by enhancing efficacy, leveraging synergistic effects, optimizing therapy utilization, tailoring treatment approaches, reducing drug resistance, and minimizing side effects. CaCO3 nanocarriers can be employed for combination therapy by integrating drug therapy with photodynamic therapy, photothermal therapy, sonodynamic therapy, immunotherapy, radiation therapy, radiofrequency ablation therapy, and imaging. This review provides an overview of recent advancements in CaCO3 nanocarriers for drug delivery and combination therapy in cancer treatment over the past five years. Furthermore, insightful perspectives on future research directions and development of CaCO3 nanoparticles as nanocarriers in cancer treatment are discussed.

Acid and Glutathione Dual-Responsive, Injectable and Self-Healing Hydrogels for Controlled Drug Delivery

Considering the complexity of physiological microenvironments and the risks of surgical infection, there still remains critical demand to develop a hydrogel as a drug release platform with multifunctional properties, including good neutral stability and sensitive multiple stimuli-responsive behaviors, as well as injectable and self-healing properties. Herein, we present a facile preparation of injectable, self-healing hydrogels with acid and glutathione (GSH) dual-responsiveness for controlled drug delivery. Initially, the anticancer drug camptothecin (CPT) was premodified with disulfide bonds and attached to poly(ethylenimine) (PEI) via the Schiff base reaction, resulting in PEI-CPT. Subsequently, OSA-IR780 was synthesized through the Schiff base reaction involving IR780 with amine groups (IR780-NH2) and oxidized sodium alginate with aldehyde groups (OSA). The formation of PEI-CPT/OSA-IR780 hydrogels with various solid contents occurred rapidly within 40 s through a simple mixing process of the aqueous solution of PEI-CPT and OSA-IR780. These hydrogels exhibited remarkable stability under neutral conditions and controlled release of CPT upon exposure to simulated tumor environments characterized by acidic conditions and elevated GSH concentrations. Furthermore, they had significant injectable and self-healing properties due to the dynamically imine-cross-linked networks. In addition, the prepared hydrogels exhibited long-term biodegradability and biocompatibility. Collectively, these features indicate the great potential of PEI-CPT/OSA-IR780 hydrogels as therapeutic delivery vehicles.

Recent Developments in CaCO3 Nano-Drug Delivery Systems: Advancing Biomedicine in Tumor Diagnosis and Treatment

Calcium carbonate (CaCO3), a natural common inorganic material with good biocompatibility, low toxicity, pH sensitivity, and low cost, has a widespread use in the pharmaceutical and chemical industries. In recent years, an increasing number of CaCO3-based nano-drug delivery systems have been developed. CaCO3 as a drug carrier and the utilization of CaCO3 as an efficient Ca2+ and CO2 donor have played a critical role in tumor diagnosis and treatment and have been explored in increasing depth and breadth. Starting from the CaCO3-based nano-drug delivery system, this paper systematically reviews the preparation of CaCO3 nanoparticles and the mechanisms of CaCO3-based therapeutic effects in the internal and external tumor environments and summarizes the latest advances in the application of CaCO3-based nano-drug delivery systems in tumor therapy. In view of the good biocompatibility and in vivo therapeutic mechanisms, they are expected to become an advancing biomedicine in the field of tumor diagnosis and treatment.

Hydrogen Ion Capturing Hydrogel Microspheres for Reversing Inflammaging

Inflammaging is deeply involved in aging-related diseases and can be destructive during aging. The maintenance of pH balance in the extracellular microenvironment can alleviate inflammaging and repair aging-related tissue damage. In this study, the hydrogen ion capturing hydrogel microsphere (GMNP) composed of mineralized transforming growth factor-β (TGF-β) and catalase (CAT) nanoparticles is developed via biomimetic mineralization and microfluidic technology for blocking the NLRP3 cascade axis in inflammaging. This GMNP can neutralize the acidic microenvironment by capturing excess hydrogen ions through the calcium carbonate mineralization layer. Then, the subsequent release of encapsulated TGF-β and CAT can eliminate both endogenous and exogenous stimulus of NLRP3, thus suppressing the excessive activation of inflammaging. In vitro, GMNP can suppress the excessive activation of the TXNIP/NLRP3/IL-1β cascade axis and enhance extracellular matrix (ECM) synthesis in nucleus pulposus cells. In vivo, GMNP becomes a sustainable and stable niche with microspheres as the core to inhibit inflammaging and promote the regeneration of degenerated intervertebral discs. Therefore, this hydrogen ion-capturing hydrogel microsphere effectively reverses inflammaging by interfering with the excessive activation of NLRP3 in the degenerated tissues.

A Booster for Radiofrequency Ablation: Advanced Adjuvant Therapy via In Situ Nanovaccine Synergized with Anti-programmed Death Ligand 1 Immunotherapy for Systemically Constraining Hepatocellular Carcinoma

Radiofrequency ablation (RFA) is one of the most common minimally invasive techniques for treating hepatocellular carcinoma (HCC), which could destroy tumors through hyperthermia and generate massive tumor-associated antigens (TAAs). However, residual malignant tissues or small satellite lesions are hard to eliminate, generally resulting in metastases and recurrence. Herein, an advanced in situ nanovaccine formed by layered double hydroxides carrying cGAMP (STING agonist) (LDHs-cGAMP) and adsorbed TAAs was designed to potentiate the RFA-induced antitumor immune response. As-prepared LDHs-cGAMP could effectively enter cancerous or immune cells, inducing a stronger type I interferon (IFN-I) response. After further adsorption of TAAs, nanovaccine generated sustained immune stimulation and efficiently promoted activation of dendritic cells (DCs). Notably, infiltrations of cytotoxic lymphocytes (CTLs) and activated DCs in tumor and lymph nodes were significantly enhanced after nanovaccine treatment, which distinctly inhibited primary, distant, and metastasis of liver cancer. Furthermore, such a nanovaccine strategy greatly changed the tumor immune microenvironment and promoted the response efficiency of anti-programmed death ligand 1 (αPD-L1) immunotherapy, significantly arresting the poorly immunogenic hepa1-6 liver cancer progression. These findings demonstrate the potential of nanovaccine as a booster for RFA in liver cancer therapy and provide a promising in situ cancer vaccination strategy.

A Multivalent Personalized Vaccine Orchestrating Two-Signal Activation Rebuilds the Bridge Between Innate and Adaptive Antitumor Immunity

Personalized vaccines capable of circumventing tumor heterogeneity have exhibited compelling prospects. However, their therapeutic benefit is greatly hindered by the limited antigen repertoire and poor response of CD8+ T-cell immunity. Here, a double-signal coregulated cross-linking hydrogel-based vaccine (Bridge-Vax) is engineered to rebuild the bridge between innate and adaptive immunity for activating CD8+ T-cells against full repertoire of tumor antigens. Mechanistically, unlike prominent CD4+ T-cell responses in most cases, administration of Bridge-Vax encapsulated with granulocyte-macrophage colony-stimulating factor concentrates a wave of dendritic cells (DCs), which further promotes DCs activation with costimulatory signal by the self-adjuvanted nature of polysaccharide hydrogel. Simultaneously, synergy with the increased MHC-I epitopes by codelivered simvastatin for cross-presentation enhancement, Bridge-Vax endows DCs with necessary two signals for orchestrating CD8+ T-cell activation. Bridge-Vax elicits potent antigen-specific CD8+ T-cell responses in vivo, which not only shows efficacy in B16-OVA model but confers specific immunological memory to protect against tumor rechallenge. Moreover, personalized multivalent Bridge-Vax tailored by leveraging autologous tumor cell membranes as antigens inhibits postsurgical B16F10 tumor recurrence. Hence, this work provides a facile strategy to rebuild the bridge between innate and adaptive immunity for inducing potent CD8+ T-cell immunity and would be a powerful tool for personalized cancer immunotherapy.

Nano-immunotherapy: overcoming delivery challenge of immune checkpoint therapy

Immune checkpoint (ICP) molecules expressed on tumor cells can suppress immune responses against tumors. ICP therapy promotes anti-tumor immune responses by targeting inhibitory and stimulatory pathways of immune cells like T cells and dendritic cells (DC). The investigation into the combination therapies through novel immune checkpoint inhibitors (ICIs) has been limited due to immune-related adverse events (irAEs), low response rate, and lack of optimal strategy for combinatorial cancer immunotherapy (IMT). Nanoparticles (NPs) have emerged as powerful tools to promote multidisciplinary cooperation. The feasibility and efficacy of targeted delivery of ICIs using NPs overcome the primary barrier, improve therapeutic efficacy, and provide a rationale for more clinical investigations. Likewise, NPs can conjugate or encapsulate ICIs, including antibodies, RNAs, and small molecule inhibitors. Therefore, combining the drug delivery system (DDS) with ICP therapy could provide a profitable immunotherapeutic strategy for cancer treatment. This article reviews the significant NPs with controlled DDS using current data from clinical and pre-clinical trials on mono- and combination IMT to overcome ICP therapeutic limitations.

Induction of Tumor Ferroptosis-Dependent Immunity via an Injectable Attractive Pickering Emulsion Gel

The combination of ferroptosis inducers and immune checkpoint blockade can enhance antitumor effects. However, the efficacy in tumors with low immunogenicity requires further investigation. In this work, a water-in-oil Pickering emulsion gel is developed to deliver (1S, 3R)-RSL-3 (RSL-3), a ferroptosis inducer dissolved in iodized oil, and programmed death-1 (PD-1) antibody, the most commonly used immune checkpoint inhibitor dissolved in water, with optimal characteristics (RSL-3 + PD-1@gel). Tumor lipase degrades the continuous oil phase, which results in the slow release of RSL-3 and PD-1 antibody and a notable antitumor effect against low-immunogenic hepatocellular carcinoma and pancreatic cancer. Intriguingly, the RSL-3 + PD-1@gel induces ferroptosis of tumor cells, resulting in antitumor immune response via accumulation of helper T lymphocyte cells and cytotoxic T cells. Additionally, the single-cell sequence profiling analysis during tumor treatment reveals the induction of ferroptosis in tumor cells together with strong antitumor immune response in ascites.

Precisely Amplifying Intracellular Oxidative Storm by Metal-Organic Coordination Polymers to Augment Anticancer Immunity

Oxidative stress accompanying the reactive oxygen species (ROS) burst governs immunocyte infiltration, activation, and differentiation in tumor microenvironments and thus can elicit robust antitumor immunity. Here, we identify a photoactive metal-organic coordination polymer (MOCP), composed of an organometallic core formed by cytotoxic mitoxantrone (MTX) acylates and photosensitive Ru(BIQ)-HDBB [BIQ = 2,2'-biquinoline, HDBB = 4,4'-di(4-benzoato)-2,2'-bipyridine] linked by Fe(II) ions via coordinate covalent bonds and an amphipathic shell encapsulating cholesterol-modified siRNA against GPX4 (siGPX4) via hydrophobic force, to precisely amplify intracellular oxidative storm. MOCPs simultaneously encapsulated MTX, Ru, and siGPX4 with efficiencies >98% and loaded Fe with efficiencies of ∼0.49%. With longer blood circulation and higher tumor accumulation, MOCPs with a 670 nm LED irradiation generate abundant ROS to induce biomembrane dysfunction and subsequently contribute to ferroptotic and immunogenic cell death, which drive tumor-associated antigen-specific immunity. MTX analogs contributed to Type I immunogenic cell death (ICD), while oxidative storm served as a damager for endo/lysosomal escape, an initiator for ferroptosis, and an inducer for type II ICD. Moreover, the blockade of CD73 that reduces extoATP catabolism unleashes immunosuppression, finally enhancing antitumor immune stimulation of MOCPs to promote orthotopic mammary cancer regression and prevent postoperative advanced cancer from recurrence and metastasis. MOCPs by exposing sufficient antigenicity thus provide a platform to synergize immune checkpoint inhibitors for the treatment of immunologically cold tumors.

Tumor Therapy Strategies Based on Microenvironment-Specific Responsive Nanomaterials

The tumor microenvironment (TME) is a complex and variable region characterized by hypoxia, low pH, high redox status, overexpression of enzymes, and high-adenosine triphosphate concentrations. In recent years, with the continuous in-depth study of nanomaterials, more and more TME-specific response nanomaterials are used for tumor treatment. However, the complexity of the TME causes different types of responses with various strategies and mechanisms of action. Aiming to systematically demonstrate the recent advances in research on TME-responsive nanomaterials, this work summarizes the characteristics of TME and outlines the strategies of different TME responses. Representative reaction types are illustrated and their merits and demerits are analyzed. Finally, forward-looking views on TME-response strategies for nanomaterials are presented. It is envisaged that such emerging strategies for the treatment of cancer are expected to exhibit dramatic trans-clinical capabilities, demonstrating the extensive potential for the diagnosis and therapy of cancer.

Circadian Clock Regulation via Biomaterials for Nucleus Pulposus

Circadian clock disorder during tissue degeneration has been considered the potential pathogenesis for various chronic diseases, such as intervertebral disc degeneration (IVDD). In this study, circadian clock-regulating biomaterials (ClockMPs) that can effectively activate the intrinsic circadian clock of nucleus pulposus cells (NPCs) in IVDD and improve the physiological function of NPCs for disc regeneration are fabricated via air-microfluidic technique and the chemical cross-linking between polyvinyl alcohol and modified-phenylboronic acid. In vitro experiments verified that ClockMPs can scavenge reactive oxygen species to maintain a stable microenvironment for the circadian clock by promoting the binding of BMAL1 and CLOCK proteins. ClockMPs can regulate the expression of core circadian clock genes by activating the PI3K-AKT pathway in NPCs to remodel the intrinsic circadian clock and promote extracellular matrix synthesis. Furthermore, in vivo experiments of IVDD treated with ClockMPs proved that ClockMPs can promote disc regeneration by regulating the circadian clock of NPCs. In conclusion, ClockMPs provided a novel and promising strategy for circadian clock regulation during tissue regeneration.

Advances in PD-1 signaling inhibition-based nano-delivery systems for tumor therapy

In recent years, cancer immunotherapy has emerged as an exciting cancer treatment. Immune checkpoint blockade brings new opportunities for more researchers and clinicians. Programmed cell death receptor-1 (PD-1) is a widely studied immune checkpoint, and PD-1 blockade therapy has shown promising results in a variety of tumors, including melanoma, non-small cell lung cancer and renal cell carcinoma, which greatly improves patient overall survival and becomes a promising tool for the eradication of metastatic or inoperable tumors. However, low responsiveness and immune-related adverse effects currently limit its clinical application. Overcoming these difficulties is a major challenge to improve PD-1 blockade therapies. Nanomaterials have unique properties that enable targeted drug delivery, combination therapy through multidrug co-delivery strategies, and controlled drug release through sensitive bonds construction. In recent years, combining nanomaterials with PD-1 blockade therapy to construct novel single-drug-based or combination therapy-based nano-delivery systems has become an effective mean to address the limitations of PD-1 blockade therapy. In this study, the application of nanomaterial carriers in individual delivery of PD-1 inhibitors, combined delivery of PD-1 inhibitors and other immunomodulators, chemotherapeutic drugs, photothermal reagents were reviewed, which provides effective references for designing new PD-1 blockade therapeutic strategies.

Photoallosteric Polymersomes toward On-Demand Drug Delivery and Multimodal Cancer Immunotherapy

Allosteric transitions can modulate the self-assembly and biological function of proteins. It remains, however, tremendously challenging to design synthetic allosteric polymeric assemblies with spatiotemporally switchable hierarchical structures and functionalities. Here, a photoallosteric polymersome is constructed that undergoes a rapid conformational transition from β-sheet to α-helix upon exposure to near-infrared light irradiation. In addition to improving nanoparticle cell penetration and lysosome escape, photoinduced allosteric behavior reconstructs the vesicular membrane structure, which stimulates the release of hydrophilic cytolytic peptide melittin and hydrophobic kinase inhibitor sorafenib. Combining on-demand delivery of multiple therapeutics with phototherapy results in apoptosis and immunogenic death of tumor cells, remold the immune microenvironment and achieve an excellent synergistic anticancer efficacy in vivo without tumor recurrence and metastasis. Such a light-modulated allosteric transition in non-photosensitive polymers provides new insight into the development of smart nanomaterials for biosensing and drug delivery applications.

Bioorthogonal nanozymes for breast cancer imaging and therapy

Bioorthogonal catalysis via transition metal catalysts (TMCs) enables the generation of therapeutics locally through chemical reactions not accessible by biological systems. This localization can enhance the efficacy of anticancer treatment while minimizing off-target effects. The encapsulation of TMCs into nanomaterials generates "nanozymes" to activate imaging and therapeutic agents. Here, we report the use of cationic bioorthogonal nanozymes to create localized "drug factories" for cancer therapy in vivo. These nanozymes remained present at the tumor site at least seven days after a single injection due to the interactions between cationic surface ligands and negatively charged cell membranes and tissue components. The prodrug was then administered systemically, and the nanozymes continuously converted the non-toxic molecules into active drugs locally. This strategy substantially reduced the tumor growth in an aggressive breast cancer model, with significantly reduced liver damage compared to traditional chemotherapy.

Curvature-sensing peptide inhibits tumour-derived exosomes for enhanced cancer immunotherapy

Tumour-derived exosomes (T-EXOs) impede immune checkpoint blockade therapies, motivating pharmacological efforts to inhibit them. Inspired by how antiviral curvature-sensing peptides disrupt membrane-enveloped virus particles in the exosome size range, we devised a broadly useful strategy that repurposes an engineered antiviral peptide to disrupt membrane-enveloped T-EXOs for synergistic cancer immunotherapy. The membrane-targeting peptide inhibits T-EXOs from various cancer types and exhibits pH-enhanced membrane disruption relevant to the tumour microenvironment. The combination of T-EXO-disrupting peptide and programmed cell death protein-1 antibody-based immune checkpoint blockade therapy improves treatment outcomes in tumour-bearing mice. Peptide-mediated disruption of T-EXOs not only reduces levels of circulating exosomal programmed death-ligand 1, but also restores CD8⁺ T cell effector function, prevents premetastatic niche formation and reshapes the tumour microenvironment in vivo. Our findings demonstrate that peptide-induced T-EXO depletion can enhance cancer immunotherapy and support the potential of peptide engineering for exosome-targeting applications.

Boosting Checkpoint Immunotherapy with Biomaterials

The immune checkpoint blockade (ICB) therapy has revolutionized the field of cancer treatment, while low response rates and systemic toxicity limit its clinical outcomes. With the rapid advances in nanotechnology and materials science, various types of biomaterials have been developed to maximize therapeutic efficacy while minimizing side effects by increasing tumor antigenicity, reversing immunosuppressive microenvironment, amplifying antitumor immune response, and reducing extratumoral distribution of checkpoint inhibitors as well as enhancing their retention within target sites. In this review, we reviewed current design strategies for different types of biomaterials to augment ICB therapy effectively and then discussed present representative biomaterial-assisted immune modulation and targeted delivery of checkpoint inhibitors to boost ICB therapy. Current challenges and future development prospects for expanding the ICB with biomaterials were also summarized. We anticipate this review will be helpful for developing emerging biomaterials for ICB therapy and promoting the clinical application of ICB therapy.

"Cold" colorectal cancer faces a bottleneck in immunotherapy

The advent of immunotherapy and the development of immune checkpoint inhibitors (ICIs) are changing the way we think about cancer treatment. ICIs have shown clinical benefits in a variety of tumor types, and ICI-based immunotherapy has shown effective clinical outcomes in immunologically "hot" tumors. However, for immunologically "cold" tumors such as colorectal cancer (CRC), only a limited number of patients are currently benefiting from ICIs due to limitations such as individual differences and low response rates. In this review, we discuss the classification and differences between hot and cold CRC and the current status of research on cold CRC, and summarize the treatment strategies and challenges of immunotherapy for cold CRC. We also explain the mechanism, biology, and role of immunotherapy for cold CRC, which will help clarify the future development of immunotherapy for cold CRC and discovery of more emerging strategies for the treatment of cold CRC.

Application of injectable hydrogels in cancer immunotherapy

Immunotherapy is a revolutionary and promising approach to cancer treatment. However, traditional cancer immunotherapy often has the disadvantages of limited immune response rate, poor targeting, and low treatment index due to systemic administration. Hydrogels are drug carriers with many advantages. They can be loaded and transported with immunotherapeutic agents, chemical anticancer drugs, radiopharmaceuticals, photothermal agents, photosensitizers, and other therapeutic agents to achieve controlled release of drugs, extend the retention time of drugs, and thus successfully trigger anti-tumor effects and maintain long-term therapeutic effects after administration. This paper reviews recent advances in injectable hydrogel-based cancer immunotherapy, including immunotherapy alone, immunotherapy with combination chemotherapy, radiotherapy, phototherapy, and DNA hydrogel-based immunotherapy. Finally, we review the potential and limitations of injectable hydrogels in cancer immunotherapy.

Reactive oxygen species-responsive polymer drug delivery systems

Applying reactive polymer materials sensitive to biological stimuli has recently attracted extensive research interest. The special physiological effects of reactive oxygen species (ROS) on tumors or inflammation and the application of ROS-responsive polymers as drug-delivery systems in organisms have attracted much attention. ROS is a vital disease signal molecule, and the unique accumulation of ROS-responsive polymers in pathological sites may enable ROS-responsive polymers to deliver payload (such as drugs, ROS-responsive prodrugs, and gene therapy fragments) in a targeted fashion. In this paper, the research progress of ROS-responsive polymers and their application in recent years were summarized and analyzed. The research progress of ROS-responsive polymers was reviewed from the perspective of nanoparticle drug delivery systems, multi-responsive delivery systems, and ROS-responsive hydrogels. It is expected that our work will help understand the future development trends in this field.

Advances in 3D culture systems for therapeutic discovery and development in brain cancer

This review focuses on recent advances in 3D culture systems that promise more accurate therapeutic models of the glioblastoma multiforme (GBM) tumor microenvironment (TME), such as the unique anatomical, cellular, and molecular features evident in human GBM. The key components of a GBM TME are outlined, including microbiomes, vasculature, extracellular matrix (ECM), infiltrating parenchymal and peripheral immune cells and molecules, and chemical gradients. 3D culture systems are evaluated against 2D culture systems and in vivo animal models. The main 3D culture techniques available are compared, with an emphasis on identifying key gaps in knowledge for the development of suitable platforms to accurately model the intricate components of the GBM TME.

Locoregional Lymphatic Delivery Systems Using Nanoparticles and Hydrogels for Anticancer Immunotherapy

The lymphatic system has gained significant interest as a target tissue to control cancer progress, which highlights its central role in adaptive immune response. Numerous mechanistic studies have revealed the benefits of nano-sized materials in the transport of various cargos to lymph nodes, overcoming barriers associated with lymphatic physiology. The potential of sustained drug delivery systems in improving the therapeutic index of various immune modulating agents is also being actively discussed. Herein, we aim to discuss design rationales and principles of locoregional lymphatic drug delivery systems for invigorating adaptive immune response for efficient antitumor immunotherapy and provide examples of various advanced nanoparticle- and hydrogel-based formulations.

Targeting the epigenome in malignant melanoma: Facts, challenges and therapeutic promises

Malignant melanoma is the most lethal type of skin cancer with high rates of mortality. Although current treatment options provide a short-clinical benefit, acquired-drug resistance highlights the low 5-year survival rate among patients with advanced stage of the disease. In parallel, the involvement of an aberrant epigenetic landscape, (e.g., alterations in DNA methylation patterns, histone modifications marks and expression of non-coding RNAs), in addition to the genetic background, has been also associated with the onset and progression of melanoma. In this review article, we report on current therapeutic options in melanoma treatment with a focus on distinct epigenetic alterations and how their reversal, by specific drug compounds, can restore a normal phenotype. In particular, we concentrate on how single and/or combinatorial therapeutic approaches have utilized epigenetic drug compounds in being effective against malignant melanoma. Finally, the role of deregulated epigenetic mechanisms in promoting drug resistance to targeted therapies and immune checkpoint inhibitors is presented leading to the development of newly synthesized and/or improved drug compounds capable of targeting the epigenome of malignant melanoma.

Near infrared-activatable biomimetic nanogels enabling deep tumor drug penetration inhibit orthotopic glioblastoma

Glioblastoma multiforme (GBM) is one of the most fatal malignancies due to the existence of blood-brain barrier (BBB) and the difficulty to maintain an effective drug accumulation in deep GBM lesions. Here we present a biomimetic nanogel system that can be precisely activated by near infrared (NIR) irradiation to achieve BBB crossing and deep tumor penetration of drugs. Synthesized by crosslinking pullulan and poly(deca-4,6-diynedioic acid) (PDDA) and loaded with temozolomide and indocyanine green (ICG), the nanogels are inert to endogenous oxidative conditions but can be selectively disintegrated by ICG-generated reactive oxygen species upon NIR irradiation. Camouflaging the nanogels with apolipoprotein E peptide-decorated erythrocyte membrane further allows prolonged blood circulation and active tumor targeting. The precisely controlled NIR irradiation on tumor lesions excites ICG and deforms the cumulated nanogels to trigger burst drug release for facilitated BBB permeation and infiltration into distal tumor cells. These NIR-activatable biomimetic nanogels suppress the tumor growth in orthotopic GBM and GBM stem cells-bearing mouse models with significantly extended survival.

Three-dimensional (3D) scaffolds as powerful weapons for tumor immunotherapy

Though increasing understanding and remarkable clinical successes have been made, enormous challenges remain to be solved in the field of cancer immunotherapy. In this context, biomaterial-based immunomodulatory strategies are being developed to boost antitumor immunity. For the local immunotherapy, macroscale biomaterial scaffolds with 3D network structures show great superiority in the following aspects: facilitating the encapsulation, localized delivery, and controlled release of immunotherapeutic agents and even immunocytes for more efficient immunomodulation. The concentrating immunomodulation in situ could minimize systemic toxicities, but still exert abscopal effects to harness the power of overall anticancer immune response for eradicating malignancy. To promote such promising immunotherapies, the design requirements of macroscale 3D scaffolds should comprehensively consider their physicochemical and biological properties, such as porosity, stiffness, surface modification, cargo release kinetics, biocompatibility, biodegradability, and delivery modes. To date, increasing studies have focused on the relationships between these parameters and the biosystems which will guide/assist the 3D biomaterial scaffolds to achieve the desired immunotherapeutic outcomes. In this review, by highlighting some recent achievements, we summarized the latest advances in the development of various 3D scaffolds as niches for cancer immunotherapy. We also discussed opportunities, challenges, current trends, and future perspectives in 3D macroscale biomaterial scaffold-assisted local treatment strategies. More importantly, this review put more efforts to illustrate how the 3D biomaterial systems affect to modulate antitumor immune activities, where we discussed how significant the roles and behaviours of 3D macroscale scaffolds towards in situ cancer immunotherapy in order to direct the design of 3D immunotherapeutic.

Amoeba-inspired magnetic microgel assembly assisted by engineered dextran-binding protein for vaccination against life-threatening systemic infection

Vaccination is critical for population protection from pathogenic infections. However, its efficiency is frequently compromised by a failure of antigen retention and presentation. Herein, we designed a dextran-binding protein DexBP, which is composed of the carbohydrate-binding domains of Trichoderma reesei cellobiohydrolases Cel6A and Cel7A, together with the sequence of the fluorescent protein mCherry. DexBP was further prepared by engineered Escherichia coli cells and grafted to magnetic nanoparticles. The magnetic nanoparticles were integrated with a dextran/poly(vinyl alcohol) framework and a reactive oxygen species-responsive linker, obtaining magnetic polymeric microgels for carrying pathogen antigen. Similar to amoeba aggregation, the microgels self-assembled to form aggregates and further induced dendritic cell aggregation. This step-by-step assembly retained antigens at lymph nodes, promoted antigen presentation, stimulated humoral immunity, and protected the mice from life-threatening systemic infections. This study developed a magnetic microgel-assembling platform for dynamically regulating immune response during protection of the body from dangerous infections.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (AFM image and zeta potential of MG; TEM, FT-IR, DLS, and zeta potential of MNP-DexBP; zeta potential of MG+CaAg and MG+MNP-DexBP+CaAg; antigen release profile of MG+CaAg and MG+MNP-DexBP+CaAg; aggregation and dispersion of dendritic cells induced by MG+MNP-DexBP+CaAg; uptake of FITC-labeled CaAg (fCaAg) and intracellular distribution of fCaAg in the dendritic cells; antigen retention and dendritic cell activation in lymph nodes; and serum anti-CaAg antibody levels on day 3 after C. albicans infection in the mice pre-immunized by PBS (control), CaAg, MG+CaAg, and MG+MNP-DexBP+CaAg) is available in the online version of this article at 10.1007/s12274-022-4809-1.

Efficient Immunotherapy of Drug-Free Layered Double Hydroxide Nanoparticles via Neutralizing Excess Acid and Blocking Tumor Cell Autophagy

Cancer immunotherapy efficacy is largely limited by the suppressive tumor immune microenvironment (TIME) where antitumor immune cells are inhibited and tumor antigens continue to mutate or be lost. To remodel the TIME, we here applied weakly alkaline layered double hydroxide nanoparticles (LDH NPs) to neutralize the excess acid and block autophagy of tumor cells for neoadjuvant cancer immunotherapy. Peritumoral injection of LDH NPs provided a long-term and efficient acid-neutralization in the TIME, blocked the lysosome-mediated autophagy pathway in tumor cells, and increased the levels of antitumor tumor-associated macrophages and T cells. These LDH NPs captured tumor antigens released in the tumor tissues and effectively inhibited the growth of both melanoma and colon tumors in vivo. These findings indicate that LDH NPs, as an immunomodulator and adjuvant, successfully "awaken" and promote the host innate and adaptive immune systems, showing promising potential for solid tumor immunotherapy.