Rapamycin as a "One-Stone-Three-Birds" Agent for Cooperatively Enhanced Phototherapies Against Metastatic Breast Cancer

Mild near-infrared laser-triggered photo-immunotherapy potentiates immune checkpoint blockade via an all-in-one theranostic nanoplatform

One of the primary challenges for immune checkpoint blockade (ICB)-based therapy is the limited infiltration of T lymphocytes (T cells) into tumors, often referred to as immunologically "cold" tumors. A promising strategy to enhance the anti-tumor efficacy of ICB is to increase antigen exposure, thereby enhancing T cell activation and converting "cold" tumors into "hot" ones. Herein, we present an innovative all-in-one therapeutic nanoplatform to realize local mild photothermal- and photodynamic-triggered antigen exposure, thereby improving the anti-tumor efficacy of ICB. This nanoplatform involves conjugating programmed death-ligand 1 antibody (aPD-L1) with gadolinium-doped near-infrared (NIR)-emitting carbon dots (aPD-L1@GdCDs), which displays negligible cytotoxicity in the absence of light. But under controlled NIR laser irradiation, the GdCDs produce combined photothermal and photodynamic effects. This not only results in tumor ablation but also induces immunogenic cell death (ICD), facilitating enhanced infiltration of CD8+ T cells in the tumor area. Importantly, the combination of aPD-L1 with photothermal and photodynamic therapies via aPD-L1@GdCDs significantly boosts CD8+ T cell infiltration, reduces tumor size, and improves anti-metastasis effects compared to either GdCDs-based phototherapy or aPD-L1 alone. In addition, the whole treatment process can be monitored by multi-modal fluorescence/photoacoustic/magnetic resonance imaging (FLI/PAI/MRI). Our study highlights a promising nanoplatform for cancer diagnosis and therapy, as well as paves the way to promote the efficacy of ICB therapy through mild photothermal- and photodynamic-triggered immunotherapy.

Dual-Drug Nanomedicine Assembly with Synergistic Anti-Aneurysmal Effects via Inflammation Suppression and Extracellular Matrix Stabilization

Abdominal aortic aneurysm (AAA) represents a critical cardiovascular condition characterized by localized dilation of the abdominal aorta, carrying a significant risk of rupture and mortality. Current treatment options are limited, necessitating novel therapeutic approaches. This study investigates the potential of a pioneering nanodrug delivery system, RAP@PFB, in mitigating AAA progression. RAP@PFB integrates pentagalloyl glucose (PGG) and rapamycin (RAP) within a metal-organic-framework (MOF) structure through a facile assembly process, ensuring remarkable drug loading capacity and colloidal stability. The synergistic effects of PGG, a polyphenolic antioxidant, and RAP, an mTOR inhibitor, collectively regulate key players in AAA pathogenesis, such as macrophages and smooth muscle cells (SMCs). In macrophages, RAP@PFB efficiently scavenges various free radicals, suppresses inflammation, and promotes M1-to-M2 phenotype repolarization. In SMCs, it inhibits apoptosis and calcification, thereby stabilizing the extracellular matrix and reducing the risk of AAA rupture. Administered intravenously, RAP@PFB exhibits effective accumulation at the AAA site, demonstrating robust efficacy in reducing AAA progression through multiple mechanisms. Moreover, RAP@PFB demonstrates favorable biosafety profiles, supporting its potential translation into clinical applications for AAA therapy.

Fe3O4 Nanoparticles That Modulate the Polarisation of Tumor-Associated Macrophages Synergize with Photothermal Therapy and Immunotherapy (PD-1/PD-L1 Inhibitors) to Enhance Anti-Tumor Therapy

Introduction

Traditional surgical resection, radiotherapy, and chemotherapy have been the treatment options for patients with head and neck squamous cell carcinoma (HNSCC) over the past few decades. Nevertheless, the five-year survival rate for patients has remained essentially unchanged, and research into treatments has been relatively stagnant. The combined application of photothermal therapy (PTT) and immunotherapy for treating HNSCC has considerable potential.

Methods

Live-dead cell staining and CCK-8 assays proved that Fe3O4 nanoparticles are biocompatible in vitro. In vitro, cellular experiments utilized flow cytometry and immunofluorescence staining to verify the effect of Fe3O4 nanoparticles on the polarisation of tumor-associated macrophages. In vivo, animal experiments were conducted to assess the inhibitory effect of Fe3O4 nanoparticles on tumor proliferation under the photothermal effect in conjunction with BMS-1. Tumour tissue sections were stained to observe the effects of apoptosis and the inhibition of tumor cell proliferation. The histological damage to animal organs was analyzed by hematoxylin and eosin (H&E) staining.

Results

The stable photothermal properties of Fe3O4 nanoparticles were validated by in vitro cellular and in vivo animal experiments. Fe3O4 photothermal action not only directly triggered immunogenic cell death (ICD) and enhanced the immunogenicity of the tumor microenvironment but also regulated the expression of tumor-associated macrophages (TAMs), up-regulating CD86 and down-regulating CD206 to inhibit tumor growth. The PD-1/PD-L1 inhibitor promoted tumor suppression, and reduced tumor recurrence and metastasis. In vivo studies demonstrated that the photothermal action exhibited a synergistic effect when combined with immunotherapy, resulting in significant suppression of primary tumors and an extension of survival.

Conclusion

In this study, we applied Fe3O4 photothermolysis in a biomedical context, combining photothermolysis with immunotherapy, exploring a novel pathway for treating HNSCC and providing a new strategy for effectively treating HNSCC.

ROS-responsive core-shell nano-inhibitor impedes pyruvate metabolism for reinforced photodynamic therapy and interrupted pre-metastatic niche formation

The formation of pre-metastatic niche (PMN) in a hospitable organ derived from the primary tumor requires the communication between the tumor cells and the host environment. Pyruvate is a fundamental nutrient by which the tumor cells metabolically reshape the extracellular matrix in the lung to facilitate their own metastatic development. Here we report a combination regimen by integrating the photo-sensitizer and the mitochondrial pyruvate carrier (MPC) inhibitor in a dendritic polycarbonate core-hyaluronic acid shell nano-platform with multivalent reversible crosslinker embedded in it (DOH-NI+L) to reinforce photodynamic therapy (PDT) toward the primary tumor and interrupt PMN formation in the lung via impeding pyruvate uptake. We show that DOH-NI+L mediates tumor-specific MPC inhibitor liberation, inhibiting the aerobic respiration for facilitated PDT and restraining ATP generation for paralyzing cell invasion. Remarkably, DOH-NI+L is demonstrated to block the metabolic crosstalk of tumor cell-host environment by dampening pyruvate metabolism, provoking a series of metabolic responses and resulting in the pulmonary PMN interruption. Consequently, DOH-NI+L realizes a significant primary tumor inhibition and an efficient pulmonary metastasis prevention. Our research extends nano-based anti-metastatic strategies aiming at PMN intervention and such a dendritic core-shell nano-inhibitor provides an innovative paradigm to inhibit tumor growth and prevent metastasis efficiently. STATEMENT OF SIGNIFICANCE: In the progression of cancer metastasis, the formation of a pre-metastatic niche (PMN) in a hospitable organ derived from the primary tumor is one of the rate-limiting stages. The current nano-based anti-metastatic modalities mainly focus on targeted killing of tumor cells and specific inhibition of tumor cell invasion, while nanomedicine-mediated interruption of PMN formation has been rarely reported. Here we report a combination regimen by integrating a photo-sensitizer and an inhibitor of mitochondrial pyruvate carrier in a dendritic core-shell nano-platform with a reversible crosslinker embedded in it to reinforce PDT toward the primary tumor and interrupt PMN formation via impeding the uptake of pyruvate that is a fundamental nutrient facilitating aerobic respiration and PMN formation. Our research proposed a nano-based anti-metastatic strategy aiming at PMN intervention.

Functionalization of and through Melanin: Strategies and Bio-Applications

A unique feature of nanoparticles for bio-application is the ease of achieving multi-functionality through covalent and non-covalent functionalization. In this way, multiple therapeutic actions, including chemical, photothermal and photodynamic activity, can be combined with different bio-imaging modalities, such as magnetic resonance, photoacoustic, and fluorescence imaging, in a theragnostic approach. In this context, melanin-related nanomaterials possess unique features since they are intrinsically biocompatible and, due to their optical and electronic properties, are themselves very efficient photothermal agents, efficient antioxidants, and photoacoustic contrast agents. Moreover, these materials present a unique versatility of functionalization, which makes them ideal for the design of multifunctional platforms for nanomedicine integrating new functions such as drug delivery and controlled release, gene therapy, or contrast ability in magnetic resonance and fluorescence imaging. In this review, the most relevant and recent examples of melanin-based multi-functionalized nanosystems are discussed, highlighting the different methods of functionalization and, in particular, distinguishing pre-functionalization and post-functionalization. In the meantime, the properties of melanin coatings employable for the functionalization of a variety of material substrates are also briefly introduced, especially in order to explain the origin of the versatility of melanin functionalization. In the final part, the most relevant critical issues related to melanin functionalization that may arise during the design of multifunctional melanin-like nanoplatforms for nanomedicine and bio-application are listed and discussed.

NIR-II-triggered photothermal therapy with Au@PDA/PEG-PI for targeted downregulation of PSMA in prostate cancer

Although positron emission tomography (PET) imaging products targeting prostate-specific membrane antigen (PSMA) have been approved for marketing, clinical challenges remain in the study of its use as a therapeutic target, such as the complex synthesis process and side effects after treatment. Here, we developed a strategy for targeted photothermal therapy (PTT) using PSMA as the target. The results of molecular docking demonstrated that the synthesized PEG modified urea-based PSMA inhibitor (small molecular PSMA inhibitor, PI) PI-PEG has a high affinity energy (binding energy = - 8.3 kcal mol^-1) for the PSMA target. Therefore, modification of PI-PEG onto the surface of gold@polydopamine (Au@PDA) with NIR-II absorption could enable targeted PTT against PSMA. This work revealed that the prepared Au@PDA/PEG-PI were not only highly selective for PSMA, but also could efficiently ablate PSMA expression by targeted PTT at the maximum permissible exposure (MPE) of the NIR-II laser. Moreover, Au@PDA/PEG-PI also have potential for photoacoustic (PA) imaging and computed tomography (CT) imaging. As the first strategy to downregulate the expression of PSMA and successfully inhibit prostate cancer by targeted PTT, this study case provides a new idea for the clinical translation of PSMA as an integrated target for tumor diagnosis and anti-tumor treatment. STATEMENT OF SIGNIFICANCE: (1) Au@PDA/PEG-PI NPs were the novel PTT agent to target PSMA and successfully down-regulate PSMA expression. (2) Molecular docking results demonstrated that PI-PEG inhibitors have a high affinity energy for PSMA (binding energy = - 8.3 kcal mol^-1). (3) Au@PDA/PEG-PI NPs can be targeted for efficient PTT at the MPE of the NIR-II laser. (4) Au@PDA/PEG-PI NPs also have the potential for PA and CT imaging.

Applications of metal-phenolic networks in nanomedicine: a review

The exploration of nanomaterials is beneficial for the development of nanomedicine and human medical treatment. Metal-phenolic networks (MPNs) have been introduced as a nanoplatform for versatile functional hybrid nanomaterials and have attracted extensive attention due to their simple preparation, excellent properties and promising medical application prospects. This review presents an overview of recent synthesis methods for MPNs, their unique biomedical properties and the research progress in their application in disease detection and treatment. First, the synthesis methods of MPNs are summarised, and then the advantages and applicability of each assembly method are emphasised. The various functions exhibited by MPNs in biomedical applications are then introduced. Finally, the latest research progress in MPN-based nanoplatforms in the biomedical field is discussed, and their future research and application are investigated.

Injectable hyaluronan/MnO2 nanocomposite hydrogel constructed by metal-hydrazide coordinated crosslink mineralization for relieving tumor hypoxia and combined phototherapy

Hydrogel-based drug delivery holds great promise in topical tumor treatment. However, the simple construction of multifunctional therapeutic hydrogels under physiological conditions is still a huge challenge. Herein, for the first time, a multifunctional hyaluronan/MnO₂ nanocomposite (HHM) hydrogel with injectable and self-healing capabilities was constructed under physiological conditions through innovative in situ mineralization-triggered Mn-hydrazide coordination crosslinking. The hydrogel formed from Mn²⁺ and hydrazided hyaluronan under optimized conditions exhibited a high elastic modulus >1 kPa, injectability, self-healing function, stimuli-responsiveness and catalase-like activity. In vitro and in vivo biological experiments demonstrated that our HHM hydrogel could not only efficiently relieve hypoxia by in situ catalytic decomposition of endogenous H₂O₂ into O₂ but also achieve synergistic photodynamic/photothermal therapy of 4T1 breast cancer in a mouse tumor model. This study presented a novel mineralization-driven metal-hydrazide coordination crosslinking approach and developed a multifunctional therapeutic platform for O₂-enhanced efficient topical dual-phototherapy of breast cancer.

Triggering Immune System With Nanomaterials for Cancer Immunotherapy

Cancer is a major cause of incidence rate and mortality worldwide. In recent years, cancer immunotherapy has made great progress in the preclinical and clinical treatment of advanced malignant tumors. However, cancer patients will have transient cancer suppression reaction and serious immune related adverse reactions when receiving immunotherapy. In recent years, nanoparticle-based immunotherapy, which can accurately deliver immunogens, activate antigen presenting cells (APCs) and effector cells, provides a new insight to solve the above problems. In this review, we discuss the research progress of nanomaterials in immunotherapy including nanoparticle-based delivery systems, nanoparticle-based photothermal and photodynamic immunotherapy, nanovaccines, nanoparticle-based T cell cancer immunotherapy and nanoparticle-based bacteria cancer immunotherapy. We also put forward the current challenges and prospects of immunomodulatory therapy.

Anti-PD-L1 DNAzyme Loaded Photothermal Mn2+ /Fe3+ Hybrid Metal-Phenolic Networks for Cyclically Amplified Tumor Ferroptosis-Immunotherapy

Ferroptosis can activate immune response via inducing tumor cells immunogenic cell death (ICD), and antitumor immunity in turn boosts the efficacy of ferroptosis by excreting interferon gamma (IFN-γ), which shows a promising combo for synergistically amplified tumor treatment. However, their combination is strictly limited by the complexity of tumor microenvironment, including poor ferroptosis response and immunosuppressive factors in tumor. Herein, a metal-phenolic networks (MPNs) nanoplatform with all-active components is constructed to favor the ferroptosis-immunotherapy cyclical synergism. The photothermal MPNs are assembled via coordination between tannic acid (TA) and metal-ion complex of Fe³⁺ /Mn²⁺ , through which a PD-L1 inhibiting DNAzyme (DZ) is loaded to regulate the immunosuppressive PD-1/PD-L1 pathway. After intracellular delivery, each component of MPNs exerts their respective functions: Fe²⁺ is in situ generated from Fe³⁺ by TA reduction to trigger ferroptosis, while DZ is activated by Mn²⁺ to effectively silence PD-L1. With external laser irradiation, photothermal therapy is initiated to synergize with ferroptosis for enhanced ICD, which induces strong antitumor immunes. Combined with DZ-mediated PD-L1 suppression, a cyclically amplified tumor ferroptosis-immunotherapy is achieved, resulting in obliteration of both primary and distant tumor. This work provides a smart, simple, yet robust nanomedicine-based combination for self-amplified tumor treatment.

Macrophage-Mimic Hollow Mesoporous Fe-Based Nanocatalysts for Self-Amplified Chemodynamic Therapy and Metastasis Inhibition via Tumor Microenvironment Remodeling

Fe-based nanomaterials with Fenton reaction activity are promising for tumor-specific chemodynamic therapy (CDT). However, most of the nanomaterials suffer from low catalytic efficiency due to its insufficient active site exposure and the relatively high tumor intracellular pH, which greatly impede its clinical application. Herein, macrophage membrane-camouflaged carbonic anhydrase IX inhibitor (CAI)-loaded hollow mesoporous ferric oxide (HMFe) nanocatalysts are designed to remodel the tumor microenvironment with decreased intracellular pH for self-amplified CDT. The HMFe not only serves as a Fenton agent with high active-atom exposure to enhance CDT but also provides hollow cavity for CAI loading. Meanwhile, the macrophage membrane-camouflaging endows the nanocatalysts with immune evading capability and improves tumoritropic accumulation by recognizing tumor endothelium and cancer cells through α4/VCAM-1 interaction. Once internalized by tumor cells, the CAI could be specifically released, which can not only inhibit CA IX to induce intracellular H⁺ accumulation for accelerating the Fenton reaction but also could prevent tumor metastasis because of the insufficient H⁺ formation outside cells for tumor extracellular matrix degradation. In addition, the HMFe can be employed to highly efficient magnetic resonance imaging to real-time monitor the agents' bio-distribution and treatment progress. Both in vitro and in vivo results well demonstrated that the nanocatalysts could realize self-amplified CDT and breast cancer metastasis inhibition via tumor microenvironment remodeling, which also provides a promising paradigm for improving CDT and antimetastatic treatment.

Engineering nanomedicines to inhibit hypoxia-inducible Factor-1 for cancer therapy

Hypoxia-inducible factor-1 (HIF-1), an essential promoter of tumor progression, has attracted increasing attention as a therapeutic target. In addition to hypoxic cellular conditions, HIF-1 activation can be triggered by cancer treatment, which causes drug tolerance and therapeutic failure. To date, a series of effective strategies have been explored to suppress HIF-1 function, including silencing the HIF-1α gene, inhibiting HIF-1α protein translation, degrading HIF-1α protein, and inhibiting HIF-1 transcription. Furthermore, nanoparticle-based drug delivery systems have been widely developed to improve the stability and pharmacokinetics of HIF-1 inhibitors or achieve HIF-1-targeted combination therapies as a nanoplatform. In this review, we summarize the current literature on nanomedicines targeting HIF-1 to combat cancer and discuss their potential for future development.

Novel Water-Soluble Phthalocyanine-Based Small Molecule for Effective NIR Triggered Dual Phototherapy of Cancer

Photothermal therapy (PTT) synergized photodynamic therapy (PDT) indicates more hopeful future of clinical application and is of significant importance for cancer theranostic compared with monotherapy. Dual phototherapy is attracting increasing...

Layered and orthogonal assembly of hydrophilic drugs and hydrophobic photosensitizers for enhanced cancer therapy

Combinatorial tumor therapy including chemotherapy and photodynamic therapy (PDT) can compensate for the limitations of each other and significantly increase the therapeutic effect. However, considering the differences of water-soluble characteristics between chemotherapeutic drugs and photosensitizers for photodynamic therapy, simply loading these substances into the same cavities of nanocarriers is rather difficult, leading to the reduced drug loading efficiency. Here, we reported a layered and orthogonal assembly of hydrophilic drugs doxorubicin (Dox) and hydrophobic photosensitizers Chlorin e6 (Ce6) for enhancing the effect of synergistic therapeutics. The assembly was based on polydopamine (PDA) modified with β-cyclodextrin (β-CD) through the addition reaction of -HS in HS-β-CD and-C=C in PDA, then DOX and Ce6 were loaded on the PDA and in the hydrophobic cavities of β-CDs respectively with superior drug loading efficiencies (38.8 ± 0.8% and 5.4 ± 0.3% for DOX and Ce6). PDA was hydrolyzed completely under the lysosomal acidic condition, leading to the controlled release of DOX. Under NIR irradiations, DOX-based chemotherapy was successfully integrated with PDA-based photothermal and Ce6-based photodynamic therapy. Tumor specific aptamer AS1411-modified assembly provides ideal antitumor effects in vitro and in vivo with excellent biocompatibility. Collectively, this layered and orthogonal assembly offers a generalizable solution for delivering matters with distinct aqueous solubility would find broad applications not only in drug delivery but also in bio-nanotechnology.

Biomimetic polyphenol-coated nanoparticles by Co-assembly of mTOR inhibitor and photosensitizer for synergistic chemo-photothermal therapy

Rapamycin (RAPA) functions as effectively clinical immunosuppressive agent, its significant tumor growth suppression effect via various pathways in diverse cancers, especially combined with photothermal therapy, is gaining a burgeoning attention. However, its critical defects, low solubility and poor stability, have severely hampered its further application. Herein, RAPA, indocyanine green (ICG) and epigallocatechin gallate (EGCG) serving as chemotherapeutic drug, photosensitizer and biomimetic coatings, respectively, were co-assembled into carrier-free, high biocompatible ICG-RAPA-EGCG nanoparticles (IRE NPs) for synergistic cancer therapy. Particularly, the bioinspired EGCG coatings not only improved the stability of IRE NPs under physiological conditions to avert NPs disassembly and drug release, but also maintained the photostability of ICG to achieve excellent photothermal response. The results indicated that the as-prepared IRE NPs displayed good monodispersity and enhanced stability at various stored media after introducing of EGCG. Compared with monotherapy of RAPA or ICG, IRE NPs showed higher dose-dependent toxicity in MCF-7 cells, HepG2 cells and HeLa cells, especially plus near-infrared laser irradiation. Furthermore, IRE NPs exhibited quicker uptake in cells, higher accumulation in tumor region (even in 48 h) than free ICG and effectively inhibited tumor growth without side effect in H22 tumor-bearing mice. Collectively, the carrier-free IRE NPs provided a simply alternative approach to fabricate RAPA/photosensitizer co-loaded nanoparticles for combinatorial tumor therapy.