Dual-responsive supramolecular photodynamic nanomedicine with activatable immunomodulation for enhanced antitumor therapy

Prominent supramolecular systems for cancer Therapy: From structural design to tailored applications

Supramolecular materials represent a powerful class of platforms in cancer diagnosis and therapy, owing to their dynamic architectures, stimuli responsiveness, and high biocompatibility. This review focused on three representative categories-Pillarene-based systems, virus-mimetic nanoparticles (VMNs), and metal-organic frameworks (MOFs)-each offering unique structural and functional properties. Pillarene-based assemblies enable precise host-guest interactions, by being classified into amphiphilic, ionic, and chiral varieties, the robust drug loading and controlled release capabilities of the Pillarene family were emphasized. At the same time, the VMNs, including virus-like particles and virosomes, show power in cancer cell targeting and membrane penetration by emulating natural viral architectures. By discussing the fabrication and application of single-metallic, multi-metallic, and composite MOFs, their potential in multimodal diagnosis and therapy was revealed. In addition, other supramolecular categories, such as cyclodextrin and dendrimers, were introduced as well. We highlighted representative approaches and emerging methods, and comparative perspectives with traditional nanocarriers were included. A critical evaluation of pharmacokinetic behaviors, biosafety concerns, and translational limitations was also proposed, aiming to guide future research in supramolecular cancer nanomedicine. Through an integrative and forward-looking analysis, this review provided a comprehensive framework for understanding and designing supramolecular systems for precision oncology. These emerging nanotechnologies hold promise to reshape cancer medicine by enabling adaptive, targeted, and multifunctional therapeutic strategies.

Peptide-based nanoassembly enhances ferroptosis in cancer to overcome paclitaxel resistance

The development of chemotherapy resistance poses a major challenge in cancer therapy. Ferroptosis, a unique type of cell death, offers a promising strategy to combat this resistance. Herein, a peptide-based nanoassembly (PTX@CPG) consisting of paclitaxel (PTX), chlorin e6 (Ce6), and FFVLKPLGLAGK-(PEG8)3 was constructed to promote ferroptosis through reactive oxygen species (ROS) accumulation and overcome chemoresistance. Specifically, the small-sized PTX@CPG nanoparticles effectively penetrate tumors, where the microenvironment-responsive peptide is selectively cleaved by the high expression of matrix metalloproteinase 2. This process facilitates the targeted release of PTX and its reassembly into nanofibers, improving the tumor retention of Ce6 and enhancing its cellular uptake. The synergistic therapeutic effects of PTX in combination with photodynamic therapy on triple-negative breast cancer cells were validated through both in vitro and in vivo experiments. Impressively, upon laser irradiation, PTX@CPG significantly increased ROS production, thereby amplifying the ferroptosis-inducing effects of PTX. Moreover, ferroptosis triggered by PTX@CPG with laser reduced the levels of P-glycoprotein and glutathione peroxidase 4, contributing to the alleviation of chemoresistance. Overall, PTX@CPG with laser demonstrated effective spatial targeting and drug retention, enhancing ferroptosis through ROS accumulation and showcasing a promising approach for overcoming chemotherapy resistance in cancer therapy.

Hydrogel-enabled ROS-GSH modulation for sustained copper-mediated chemodynamic therapy of oral squamous cell carcinoma

Copper ion (Cu2+) has been revealed to be involved in the occurrence and development of oral squamous cell carcinoma (OSCC), making copper-mediated chemodynamic therapy (Cu-CDT) a promising treatment strategy for OSCC by elevating Cu2+ levels to generating a large amount of reactive oxygen species (ROS). However, the excessive reduced glutathione (GSH) in the tumor microenvironment can scavenge the ROS generated by Cu-CDT. While the directional co-delivery of Cu2+ and GSH-depleting agents shows promise for Cu-CDT in OSCC therapy, their rapid metabolism and the superficial nature of OSCC lesions necessitate tailored drug formulations to ensure effective bioavailability. To counteract this challenge, this work proposed a practical hydrogel-supported ROS-GSH regulation strategy, which involves the on-demand design of a copper ion-crosslinked guanosine-based hydrogel (GCD) containing dimethyl fumarate (DMF, which conjugates with GSH for consumption). It can directionally and sustainably co-deliver Cu2+ and DMF to OSCC lesions under mildly acidic pH conditions, thereby enhancing Cu-CDT efficiency through improved Cu2+ utilization and DMF-driven GSH depletion. As anticipated, the strategy sustains the generation of hydroxyl radicals, effectively inducing apoptosis and suppressing cell proliferation in CAL-27 cells, which consequently inhibits the growth of OSCC tumors. Therefore, this work highlights the GCD hydrogel's great potential as a promising Cu-CDT therapeutic platform.

Nano drug delivery systems for advanced immune checkpoint blockade therapy

Immune checkpoint inhibitors (ICIs) have been widely utilized in the first-line therapy of various types of cancer. However, immune-related adverse events (irAEs) and resistance to ICIs remain intractable challenges for immune checkpoint blockade (ICB) therapy during clinic treatment. Nano drug delivery systems (NDDSs) have shown promising potential to improve anticancer efficacy and reduce side effects of small molecular drugs. The combination of nanotechnology and ICB provides new opportunities to overcome the challenges of immunotherapy. Nanoplatforms have been employed for direct delivery of ICIs, and they are preferred vehicles for combination therapy of ICIs and other therapeutic agents. In this review, the strategies of using NDDSs for advancing ICB therapy in recent years are surveyed, emphasizing the employment of NDDSs for combination treatment by ICIs and other agents to manipulate antitumor immunity. Analysis of current strategies for applying NDDSs for ICB leads to future research directions and development trends.

Modulating Intracellular Autophagy and Macropinocytosis for Increased Neighboring Drug Delivery

Neighboring effects provided a valuable direction for in-depth penetration of nanoparticles into tumors. However, the uncontrollable drug transcytosis and limited drug uptake hindered by viscous cancer-associated fibroblasts (CAFs) greatly limit their in-depth penetration. Here, we proposed and demonstrated that intracellular autophagosomes could carry the remaining drugs to neighboring cells, and the enhanced macropinocytosis played a major role in neighboring delivery. To enhance the autophagosome-based neighboring delivery, Ca2+-doped polydopamine was prepared to load GLS1 inhibitor CB-839 and modified glutamine (839/CG) for triggering macropinocytosis-based active cells uptake. After Ca2+-release caused lysosome damage, 839/CG escaped from lysosomes and hindered the autophagosome maturation. Then, Ca2+-induced endoplasmic reticulum oscillations and glutamine starvation both increased and blocked autophagy flow, causing 839/CG-contained autophagosome accumulation. Meanwhile, the tumor increased its macropinocytosis in response to mTOR downregulation-induced glutamine hunger, causing "the more you eat, the hungrier you get". After tumor death, the 839/CG-contained autophagosomes were released and actively ingested by neighboring hungry tumor cells through macropinocytosis. Combined with the photothermal effect triggered CAF decrease, neighboring cells repeated the above process for in-depth tumor delivery. Also, immunogenic death enhanced the antigen presentation of DCs and infiltration of T cells, thereby inhibiting tumor growth and lung metastasis.

Fluorinated Cyclodextrin Supramolecular Nanoassembly Enables Oxygen-Enriched and Targeted Photodynamic Therapy

Photodynamic therapy has become a promising treatment modality against many diseases, but its dilemma-the intrinsic hypoxia of solid tumors and the high oxygen dependence for generation of cytotoxic species-has seriously hampered its practical translation. Herein a binary supramolecular nanocarrier, which is composed of fluorocarbon chain-appended β-cyclodextrin as an oxygen carrier and adamantane-grafted hyaluronic acid as a cell-targeting agent, can deliver different types of photosensitizers by multiple noncovalent interactions. Superior to the alkylated counterpart, the fluorinated amphiphilic β-cyclodextrin can spontaneously form a nanoparticulate assembly and exhibit high oxygen-enrichment performance. The obtained nanoassembly can alleviate hypoxia in the tumor microenvironment and enhance the efficacy of photodynamic therapy. Remarkable phototoxicity and minimal dark toxicity are observed in the cancer cells, and meanwhile, preferential accumulation and significant cancer ablation are realized in the tumor-bearing mice. To be envisioned, this supramolecular assembly capable of efficiently carrying oxygen can be explored as a universal platform for precise phototherapeutics.

Nitric Oxide-Producing Multiple Functional Nanoparticle Remodeling Tumor Microenvironment for Synergistic Photodynamic Immunotherapy against Hypoxic Tumor

The treatment of pancreatic cancer faces significant challenges due to connective tissue hyperplasia and severe hypoxia. Unlike oxygen-dependent Type II photosensitizers, Type I photosensitizers can produce a substantial amount of reactive oxygen species, even under hypoxic conditions, making them more suitable for photodynamic therapy of pancreatic cancer. However, the dense extracellular matrix of pancreatic cancer limits the penetration efficiency of photosensitizers, and the presence of immunosuppressive cells in the tumor microenvironment reduces the therapeutic effect. To address these challenges, we designed the photoimmunotherapeutic M1@PAP nanoparticles composed of Type I photosensitizer and anti-PD-L1 siRNA (siPD-L1), which was encapsulated into M1 macrophage membrane vesicles. In this system, pyropheophorbide-a (PPA) was covalently conjugated to poly-l-arginine (Arg9). Notably, it was capable of generating sufficient superoxide anions under hypoxic conditions, thereby functioning as a Type I photosensitizer. Furthermore, Arg9 acted as a nitric oxide (NO) donor, enhancing the penetration efficiency of the nanophotosensitizer by inhibiting cancer-associated fibroblast (CAF) activation and decomposing the tumor extracellular matrix. Additionally, M1 macrophage membrane vesicles provided active targeting capabilities and reeducated immunosuppressed M2 macrophages. The reversal of immunosuppressive microenvironment further promoted the efficacy of anti-PD-L1 siRNA immunotherapy, showing great potential in synergistic photodynamic immunotherapy against hypoxic pancreatic tumor.

Twin-Tail Tadpole-Shaped Ce6-Peptide Conjugate for Enhanced Photodynamic Cancer Therapy

Despite its therapeutic potential, photodynamic therapy faces several key limitations in clinical applications, including poor drug delivery and insufficient tumor selectivity. We engineered RFYFYR-Ce6-RFYFYR (R-Ce6-R), a twin-tail peptide-photosensitizer conjugate that self-assembles into nanostructures for improved cancer treatment. By incorporating arginine-rich peptide sequences, this design not only enhances cellular internalization but also promotes peroxynitrite (ONOO-) formation, amplifying the therapeutic effect. Our studies revealed that R-Ce6-R achieves 33-fold higher potency than unmodified Ce6, with an IC50 of 0.18 μM. The conjugate demonstrated selective accumulation in tumor tissue, robust ROS generation, and complete tumor regression in animal models while maintaining a favorable safety profile. These results establish R-Ce6-R as an innovative approach for advancing photodynamic therapy in cancer treatment.

Chlorin e6: a promising photosensitizer of anti-tumor and anti-inflammatory effects in PDT

Photodynamic therapy (PDT) involves the activation of photosensitizers (PSs) by visible laser light at the target site to catalyze the production of reactive oxygen species, resulting in tumor cell death and blood vessel closure. The efficacy of PDT depends on the PSs, the amount of oxygen, and the intensity of the excitation laser. PSs have been extensively researched, and great efforts have been made to develop an ideal photosensitizer. Chlorin-e6 is an FDA-approved second-generation PSs that has attracted widespread research interest in the medical field, especially with respect to antitumor and anti-inflammatory activity. Chlorin-e6 possesses the advantages of a large absorption coefficient, high strength, low residue in the body, and relatively high safety and thus has promising application prospects. Here we review the use of chlorin-e6 in PDT and discuss the prospects of further development of this technology.

A tumor-pH-responsive phthalocyanine as activatable type I photosensitizer for improved photodynamic immunotherapy

The development of a simple drug formulation capable of achieving both activatable type I photoreaction and tumor-responsive release of immunomodulator is crucial for advancing photodynamic immunotherapy (PDIT). Herein, we present a nanostructured photosensitizer (NP5) that is activated by the acidic tumor microenvironment to produce type I reactive oxygen species (ROS) under light irradiation and release the immunomodulator demethylcantharidin (DMC) for PDIT. The NP5 is formed by self-assembly of a versatile phthalocyanine molecule which is composed of DMC and phthalocyanine linked via a pH-responsive amide bond. NP5 produces minimal ROS under light irradiation at the condition of pH 7.4. However, NP5 can release DMC at the condition of pH 6.5 and concurrently trigger type I photoreactions. The results of in vivo experiments indicate that NP5-mediated PDIT induce the increase of cytotoxic T lymphocytes and decrease of regulatory T lymphocytes, which can effectively inhibit the bilateral tumor growth. This work is anticipated to serve as a reference for the development of innovative agents for precise PDIT of hypoxic tumors.

Lactoferrin docking NIR-II cyanine dye as a potentiated phototheranostic for synchronous multimodal bioimaging and tumor photo-immunotherapy

Rationale: A promising dye for phototheranostics, IR-1048 is a near-infrared region II (NIR-II) cyanine dye that exhibits exceptional optical characteristics in NIR-II spectrum. Unfortunately, the biological applications of IR-1048 are challenged by its hydrophobic nature, the formation of face-to-face stacked dimeric aggregates (H-aggregates) that result in pronounced spectral blue shifts, and issues related to fluorescence quenching. Method: We present a novel docking strategy involving bovine serum albumin (BSA) and lactoferrin (Lf) to construct BSA@IR-1048 and Lf@IR-1048 nanoprobes. The NIR-II optical characteristics of these nanoprobes have been thoroughly investigated through both theoretical and experimental approaches. In addition, we conducted in vitro and in vivo evaluations of their NIR-II photothermal and photodynamic properties, multimodal imaging capabilities, and effectiveness in photoimmunotherapy. Results: Following the protein docking process, both BSA@IR-1048 and Lf@IR-1048 probes exhibited a red-shifted absorbance peak and an "ON" state in NIR-II fluorescence. Theoretical analyses alongside experimental results indicate that Lf@IR-1048, which has a higher docking binding energy of -10.83 kcal/mol, significantly enhances optical characteristics in the NIR-II region. Notably, when utilizing a single NIR-II light source, Lf@IR-1048 was effective in producing single-linear state oxygen and converting photons into heat energy, achieving a photo-thermal conversion efficiency of 41.9%. The overexpression of transferrin receptors in tumor cells also improved tumor-targeting and enrichment capabilities of Lf@IR-1048, as demonstrated vitro and in vivo studies. Comparatively, Lf@IR-1048 facilitated multimodal imaging-guided NIR-II phototherapy, showing an impressive tumor development inhibition rate of 94.8%. Furthermore, in bilateral CT26 tumor-bearing mice, the Lf@IR-1048-based photo-immunotherapy exhibited significant antitumor activity, attributed to enhanced dendritic cell maturation and infiltration of cytotoxic T lymphocytes. Conclusion: Lf@IR-1048 displays a powerful combination of photothermal therapy, photodynamic therapy, and tumor-targeting potential for effective multimodal imaging-guided NIR-II phototherapy, leading to substantial inhibition of tumor growth.

Zinc oxide nanoparticles with catalase-like nanozyme activity and near-infrared light response: A combination of effective photodynamic therapy, autophagy, ferroptosis, and antitumor immunity

We prepared biocompatible and environment-friendly zinc oxide nanoparticles (ZnO NPs) with upconversion properties and catalase-like nanozyme activity. Photodynamic therapy (PDT) application is severely limited by the poor penetration of UV-Visible light and a hypoxic tumor environment. Here, we used ZnO NPs as a carrier for the photosensitizer chlorin e6 (Ce6) to construct zinc oxide-chlorin e6 nanoparticles (ZnO-Ce6 NPs), simultaneously addressing both problems. In terms of penetration, ZnO NPs convert 808 nm near-infrared light into 401 nm visible light to excite Ce6, achieving deep-penetrating photodynamic therapy under long-wavelength light. Interestingly, the ability to emit short-wavelength light under long-wavelength light is usually observed in upconversion nanoparticles. As nanozymes, ZnO NPs can catalyze the decomposition of hydrogen peroxide in tumors, providing oxygen for photodynamic action and relieving hypoxia. The enhanced photodynamic action produces a large amount of reactive oxygen species, which overactivate autophagy and trigger immunogenic cell death (ICD), leading to antitumor immunotherapy. In addition, even in the absence of light, ZnO and ZnO-Ce6 NPs can induce ferroptosis of tumor cells and exert antitumor effects.

Treg Cell Therapeutic Strategies for Breast Cancer: Holistic to Local Aspects

Regulatory T cells (Tregs) play a key role in maintaining immune homeostasis and preventing autoimmunity through their immunosuppressive function. There have been numerous reports confirming that high levels of Tregs in the tumor microenvironment (TME) are associated with a poor prognosis, highlighting their role in promoting an immunosuppressive environment. In breast cancer (BC), Tregs interact with cancer cells, ultimately leading to the suppression of immune surveillance and promoting tumor progression. This review discusses the dual role of Tregs in breast cancer, and explores the controversies and therapeutic potential associated with targeting these cells. Researchers are investigating various strategies to deplete or inhibit Tregs, such as immune checkpoint inhibitors, cytokine antagonists, and metabolic inhibition. However, the heterogeneity of Tregs and the variable precision of treatments pose significant challenges. Understanding the functional diversity of Tregs and the latest advances in targeted therapies is critical for the development of effective therapies. This review highlights the latest approaches to Tregs for BC treatment that both attenuate Treg-mediated immunosuppression in tumors and maintain immune tolerance, and advocates precise combination therapy strategies to optimize breast cancer outcomes.

Enhancing cancer immunotherapy: Nanotechnology-mediated immunotherapy overcoming immunosuppression

Immunotherapy is an important cancer treatment method that offers hope for curing cancer patients. While immunotherapy has achieved initial success, a major obstacle to its widespread adoption is the inability to benefit the majority of patients. The success or failure of immunotherapy is closely linked to the tumor's immune microenvironment. Recently, there has been significant attention on strategies to regulate the tumor immune microenvironment in order to stimulate anti-tumor immune responses in cancer immunotherapy. The distinctive physical properties and design flexibility of nanomedicines have been extensively utilized to target immune cells (including tumor-associated macrophages (TAMs), T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated fibroblasts (TAFs)), offering promising advancements in cancer immunotherapy. In this article, we have reviewed treatment strategies aimed at targeting various immune cells to regulate the tumor immune microenvironment. The focus is on cancer immunotherapy models that are based on nanomedicines, with the goal of inducing or enhancing anti-tumor immune responses to improve immunotherapy. It is worth noting that combining cancer immunotherapy with other treatments, such as chemotherapy, radiotherapy, and photodynamic therapy, can maximize the therapeutic effects. Finally, we have identified the challenges that nanotechnology-mediated immunotherapy needs to overcome in order to design more effective nanosystems.

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.

Cutting-edge approaches for targeted drug delivery in breast cancer: beyond conventional therapies

Breast cancer is a global health challenge with staggering statistics underscoring its pervasive impact. The burden of this disease is measured in terms of its prevalence and the challenges it poses to healthcare systems, necessitating a closer look at its epidemiology and impact. Current breast cancer treatments, including surgery, chemotherapy, radiation therapy, and targeted therapies, have made significant strides in improving patient outcomes. However, they are not without limitations, often leading to adverse effects and the development of drug resistance. This comprehensive review delves into the complex landscape of breast cancer, including its incidence, current treatment modalities, and the inherent limitations of existing therapeutic approaches. It also sheds light on the promising role of nanotechnology, encompassing both inorganic and organic nanoparticles equipped with the ability to selectively deliver therapeutic agents to tumor sites, in the battle against breast cancer. The review also addresses the emerging therapies, their associated challenges, and the future prospects of targeted drug delivery in breast cancer management.

Breaking Physical Barrier of Fibrotic Breast Cancer for Photodynamic Immunotherapy by Remodeling Tumor Extracellular Matrix and Reprogramming Cancer-Associated Fibroblasts

Cancer-associated fibroblasts (CAFs) assist in breast cancer (BRCA) invasion and immune resistance by overproduction of extracellular matrix (ECM). Herein, we develop FPC@S, a photodynamic immunomodulator that targets the ECM, to improve the photodynamic immunotherapy for fibrotic BRCA. FPC@S combines a tumor ECM-targeting peptide, a photosensitizer (protoporphyrin IX) and an antifibrotic drug (SIS3). After anchoring to the ECM, FPC@S causes ECM remodeling and BRCA cell death by generating reactive oxygen species (ROS) in situ. Interestingly, the ROS-mediated ECM remodeling can normalize the tumor blood vessel to improve hypoxia and in turn facilitate more ROS production. Besides, upon the acidic tumor microenvironment, FPC@S will release SIS3 for reprograming CAFs to reduce their activity but not kill them, thus inhibiting fibrosis while preventing BRCA metastasis. The natural physical barrier formed by the dense ECM is consequently eliminated in fibrotic BRCA, allowing the drugs and immune cells to penetrate deep into tumors and have better efficacy. Furthermore, FPC@S can stimulate the immune system and effectively suppress primary, distant and metastatic tumors by combining with immune checkpoint blockade therapy. This study provides different insights for the development of fibrotic tumor targeted delivery systems and exploration of synergistic immunotherapeutic mechanisms against aggressive BRCA.