Hypoxia-Responsive Tetrameric Supramolecular Polypeptide Nanoprodrugs for Combination Therapy

Light-Activated Hypoxia-Responsive Nanoparticles for Photodynamic Chemotherapy

Hypoxia is a characteristic of solid tumors, and it significantly impedes cancer treatment. Here, we report light-activated hypoxia-responsive nanoparticles NPs-TPZ consisting of 5,10,5,20-tetrakis-(4-aminophenyl)-porphine (TAPP) modified with four azobenzene groups, cyclodextrin (CD), and 3-aminobenzotriazine-1,4-di-N-oxide tirapazamine (TPZ) by the synergy of π-π stacking, host-guest, and hydrophobic interactions for synergistic photodynamic chemotherapy (PDT-CT). Under near-infrared (NIR) irradiation, the process of PDT depletes oxygen and generates singlet oxygen (1O2). The induced hypoxia exacerbation further accelerates the release and activation of TPZ. As a result, this hypoxia-responsive nanoparticle provides an effective strategy for the ablation of hypoxic solid tumors by synergistic PDT-CT.

Hypoxia-responsive core-cross-linked supramolecular nanoprodrug based on dendritic drug-drug conjugates for synergetic anticancer therapy

BACKGROUND

Recently, the strategy of self-assembling dendritic drug-drug conjugates into supramolecular nanoprodrug was widely explored in biomedical applications. Herein, we construct a hypoxia-responsive core-cross-linked supramolecular nanoprodrug (CSN-IR806/CB) based on a dendritic drug-drug conjugate.

METHODS

We prepared a hypoxia-responsive dendritic drug-drug conjugates IR806-(Azo-CB)4, which was combined with β-cyclodextrin-pendant poly(ethylene glycol)-block-poly(glutamic acid) block copolymer (PEG-PGlu-CD) to construct the core-cross-linked supramolecular nanoprodrug (CSN-IR806/CB) with enhanced physiological stability through the synergy of π-π stacking interaction, host-guest complexation, hydrogen bonds, and hydrophobic interaction.

RESULTS

The near-infrared (NIR) light irradiation of the CSN-IR806/CB treated tumor cells induced IR806-mediated PDT and PTT, and aggravated hypoxia, which triggered the disassembly of CSN-IR806/CB and the subsequent release of activated CB for synergetic cancer cell killing.

CONCLUSIONS

The CSN-IR806/CB can realize a synergistic triple therapeutic effect of photothermal therapy (PTT), photodynamic therapy (PDT), and chemotherapy (CT; i.e., PTT-PDT-CT).

Pillar[n]arene-Based Supramolecular Nanodrug Delivery Systems for Cancer Therapy

Macrocyclic supramolecular materials play an important role in encapsulating anticancer drugs to improve the anticancer efficiency and reduce the toxicity to normal tissues through host-guest interactions. Among them, pillar[n]arenes, as an emerging class of supramolecular macrocyclic compounds, have attracted increasing attention in drug delivery and drug-controlled release due to their high biocompatibility, excellent host-guest chemistry, and simplicity of modification. In this review, we summarize the research progress of pillar[n]arene-based supramolecular nanodrug delivery systems (SNDs) in recent years in the field of tumor therapy, including drug-controlled release, imaging diagnostics and therapeutic modalities. Furthermore, the opportunities and major limitations of pillar[n]arene-based SNDs for tumor therapy are discussed.

Stimuli-responsive and targeted nanomaterials: Revolutionizing the treatment of bacterial infections

Bacterial infections have emerged as a major threat to global public health. The effectiveness of traditional antibiotic treatments is waning due to the increasing prevalence of antimicrobial resistance, leading to an urgent demand for alternative antibacterial technologies. In this context, antibacterial nanomaterials have proven to be powerful tools for treating antibiotic-resistant and recurring infections. Targeting nanomaterials not only enable the precise delivery of bactericidal agents but also ensure controlled release at the infection site, thereby reducing potential systemic side effects. This review collates and categorizes nanomaterial-based responsive and precision-targeted antibacterial strategies into three key types: exogenous stimuli-responsive (including light, ultrasound, magnetism), bacterial microenvironment-responsive (such as pH, enzymes, hypoxia), and targeted antibacterial action (involving electrostatic interaction, covalent bonding, receptor-ligand mechanisms). Furthermore, we discuss recent advances, potential mechanisms, and future prospects in responsive and targeted antimicrobial nanomaterials, aiming to provide a comprehensive overview of the field's development and inspire the formulation of novel, precision-targeted antimicrobial strategies.

Photoactivated hydride therapy under hypoxia beyond ROS

As compared to oxidative phototherapy, studies on reactive reductive species-participating photodynamic therapy (PDT) are rare. Porphyrins are typical photosensitizers restricted by the oxygen level, but efficacy and selectivity are always incompatible in PDT. Herein, we report that phlorins are ideal hydride (H-) donors and explore a water-soluble triphenylphosphonium-modified zinc-coordinated porphyrin (mitoZnPor) for in situ photogeneration of zinc-cored phlorin (mitoZnPhl). Driven by 1,4-dihydronicotinamide adenine dinucleotide (NADH), the mitoZnPor/mitoZnPhl couple can reduce electron acceptors like iron heme and ubiquinone that play key roles in the mitochondrial electron transport chain (Mito-ETC). Under hypoxia, mitoZnPor showed excellent cancer-selectivity and a highly efficient in vitro PDT effect with IC50 at nanomolar levels and potent tumor growth inhibition in a 4T1 tumor-xenografted mouse model with good biosafety, which underlines the great potential of Mito-ETC targeted non-classical PDT via a H--transfer mechanism beyond reactive oxygen species (ROS) in precision cancer phototherapy using NADH as a biomarker and original electron donor.

Recent Advances of Light/Hypoxia-Responsive Azobenzene in Nanomedicine Design

Azobenzene (Azo) and its derivatives are versatile stimuli-responsive molecules. Their reversible photoisomerization and susceptibility to reduction-mediated cleavage make them valuable for various biomedical applications. Upon exposure to the UV light, Azo units undergo a thermodynamically stable trans-to-cis transition, which can be reversed by heating in the dark or irradiation with visible light. Additionally, the N=N bonds in azobenzenes can be cleaved under hypoxic conditions by azoreductase, making azobenzenes useful as hypoxia-responsive linkers. The integration of azobenzenes into nanomedicines holds promise for enhancing therapeutic efficacy, particularly in tumor targeting and controllable drug release. In this Concept paper, recent advances in the design and applications of azobenzene-based nanomedicines are updated, and future development opportunities are also summarized.

Research Progress of Disulfide Bond Based Tumor Microenvironment Targeted Drug Delivery System

Cancer poses a significant threat to human life and health. Chemotherapy is currently one of the effective cancer treatments, but many chemotherapy drugs have cell toxicity, low solubility, poor stability, a narrow therapeutic window, and unfavorable pharmacokinetic properties. To solve the above problems, target drug delivery to tumor cells, and reduce the side effects of drugs, an anti-tumor drug delivery system based on tumor microenvironment has become a focus of research in recent years. The construction of a reduction-sensitive nanomedicine delivery system based on disulfide bonds has attracted much attention. Disulfide bonds have good reductive responsiveness and can effectively target the high glutathione (GSH) levels in the tumor environment, enabling precise drug delivery. To further enhance targeting and accelerate drug release, disulfide bonds are often combined with pH-responsive nanocarriers and highly expressed ligands in tumor cells to construct drug delivery systems. Disulfide bonds can connect drug molecules and polymer molecules in the drug delivery system, as well as between different drug molecules and carrier molecules. This article summarized the drug delivery systems (DDS) that researchers have constructed in recent years based on disulfide bond drug delivery systems targeting the tumor microenvironment, disulfide bond cleavage-triggering conditions, various drug loading strategies, and carrier design. In this review, we also discuss the controlled release mechanisms and effects of these DDS and further discuss the clinical applicability of delivery systems based on disulfide bonds and the challenges faced in clinical translation.

Polymer-drug and polymer-protein conjugated nanocarriers: Design, drug delivery, imaging, therapy, and clinical applications

Polymer-drug conjugates and polymer-protein conjugates have been pivotal in the realm of drug delivery systems for over half a century. These polymeric drugs are characterized by the conjugation of therapeutic molecules or functional moieties to polymers, enabling a range of benefits including extended circulation times, targeted delivery, controlled release, and decreased immunogenicity. This review delves into recent advancements and challenges in the clinical translations and preclinical studies of polymer-drug conjugates and polymer-protein conjugates. The design principles and functionalization strategies crucial for the development of these polymeric drugs were explored followed by the review of structural properties and characteristics of various polymer carriers. This review also identifies significant obstacles in the clinical translation of polymer-drug conjugates and provides insights into the directions for their future development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Hypoxia-Responsive Polymeric Nanoprodrugs for Combo Photodynamic and Chemotherapy

Hypoxia in most solid tumors is a major challenge for photodynamic therapy (PDT), and the combination of hypoxia-activated chemotherapy and PDT is a promising approach for enhanced anticancer activity. Herein, we designed hypoxia-responsive polymeric nanoprodrug PNPs to co-deliver photosensitizer 5,10,5,20-tetrakis(4-aminophenyl)-porphine (TAPP) and chlorambucil (CB) to improve the overall therapeutic efficacy. Upon laser irradiation, the central TAPP converted oxygen to produce single oxygen (1O2) for PDT and induced PDT-reduced hypoxia environment, which accelerated the release of activated CB for synergetic cancer cell killing. Consequently, these hypoxia-responsive polymeric nanoprodrugs with a considerable drug-loading content and synergistic therapeutic effect of PDT-CT had great potential for tumor therapy.