A two-pronged strategy to alleviate tumor hypoxia and potentiate photodynamic therapy by mild hyperthermia

A mitochondria-interfering nanocomplex cooperates with photodynamic therapy to boost antitumor immunity

Immunotherapeutics against triple-negative breast cancer (TNBC) hold great promise. In this work, we provide a combination therapy for simultaneous increasing tumor immunogenicity and down-regulating programmed cell death ligand 1 (PD-L1) to boost antitumor immunity in TNBC. We prepare bis (diethyldithiocarbamate)-copper/indocyanine green nanoparticles (CuET/ICG NPs) simply in aqueous with one-pot method. CuET/ICG NPs interfere mitochondria, reduce oxygen consumption, and alleviate tumor hypoxia to potentiate photodynamic therapy (PDT) for amplifying immunogenic cell death (ICD). Meanwhile, mitochondria dysfunction leads to energy stress and activates AMPK pathway. As a result, CuET/ICG NPs downregulates membrane PD-L1 (mPD-L1) on both 4T1 cancer cells and cancer stem cells (CSCs) through AMP-activated protein kinase (AMPK)-mediated pathway in hypoxia. Cooperatively, the combinational therapy activates antitumor immunity and triggers long lasting immune memory response to resist tumor re-challenge. Our study represents an attempt that conquers tumor immunosuppressive microenvironment with simple biomedical materials and multimodality treatments.

Highly efficient tumor oxygen supplementation MnO2 nano-MOF encapsulated Sorafenib for multiple synergistic CDT/PDT/RT

Tumor growth often creates hypoxic conditions within the tumor microenvironment, which can limit the effectiveness of therapies. To address this issue, a novel "all-in-one" nanoplatform called PCN-224(Hf)@Sorafenib@(PSM) has been developed. This nanoplatform utilizes PCN-224(Hf)-modified MnO2 and combines various therapeutic modalities-chemotherapy, chemodynamic therapy (CDT), photodynamic therapy (PDT), and radiotherapy (RT)-to enhance treatment efficacy. In the PSM nanoplatform, MnO2 decomposes H2O2 to produce oxygen (O2) and reacts with glutathione (GSH) to form Mn2+. This process catalyzes a Fenton-like reaction that generates hydroxyl radicals (·OH), facilitating CDT. When exposed to 635 nm light irradiation, the porphyrin ligand in PCN-224(Hf) produces singlet oxygen (1O2), while the Hf6 clusters contribute to the PDT effects. Furthermore, the nanoplatform enhances radiotherapy by harnessing high-energy radiation. Studies have demonstrated that PSM effectively kills solid tumors even in hypoxic conditions and significantly inhibits tumor growth. This innovative nanoplatform showcases high efficacy in multimodal synergistic tumor treatment, successfully integrating multiple therapeutic approaches to overcome the challenges posed by hypoxia.

Regulation of cancer-associated fibroblasts for enhanced cancer immunotherapy using advanced functional nanomedicines: an updated review

The tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a critical role in cancer progression. It comprises various cell types, including immune cells, tumor cells, and stromal cells. Among these, cancer-associated fibroblasts (CAFs) represent a heterogeneous population with diverse origins, phenotypes, and functions. Activated CAFs secrete multiple factors that promote tumor growth, migration, angiogenesis, and contribute to chemoresistance. Additionally, CAFs secrete extracellular matrix (ECM) components, such as collagen, which form a physical barrier that hinders the penetration of chemotherapeutic and immunotherapeutic agents. This ECM also influences immune cell infiltration, impeding their ability to effectively target tumor cells. As a result, modulating the activity of CAFs has emerged as a promising strategy to enhance the efficacy of tumor immunotherapy. Nano-delivery systems, constructed from various nanomaterials with high targeting specificity and biocompatibility, offer a compelling approach to deliver therapeutic agents or immunomodulatory factors directly to CAFs. This modulation can alter CAF function, reduce their tumor-promoting effects, and thereby improve the outcomes of immunotherapy. This review provides an in-depth exploration of the origins, functions, and interactions of CAFs within the TME, particularly in the context of immune suppression. Furthermore, it discusses the potential applications of functional nanocarrifers in modulating CAFs and enhancing the effectiveness of tumor immunotherapy, highlighting the significant progress and potential of nanotechnology in this area.

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.

Drug Delivery System Targeting Cancer-Associated Fibroblast for Improving Immunotherapy

Cancer-associated fibroblasts (CAFs) are a heterogeneous population of non-malignant cells that play a crucial role in the tumor microenvironment, increasingly recognized as key contributors to cancer progression, metastasis, and treatment resistance. So, targeting CAFs has always been considered an important part of cancer immunotherapy. However, targeting CAFs to improve the efficacy of tumor therapy is currently a major challenge. Nanomaterials show their unique advantages in the whole process. At present, nanomaterials have achieved significant accomplishments in medical applications, particularly in the field of cancer-targeted therapy, showing enormous potential. It has been confirmed that nanomaterials can not only directly target CAFs, but also interact with the tumor microenvironment (TME) and immune cells to affect tumorigenesis. As for the cancer treatment, nanomaterials could enhance the therapeutic effect in many ways. Therefore, in this review, we first summarized the current understanding of the complex interactions between CAFs and TME, immune cells, and tumor cells. Next, we discussed common nanomaterials in modern medicine and their respective impacts on the TME, CAFs, and interactions with tumors. Finally, we focus on the application of nano drug delivery system targeting CAFs in cancer therapy.

Tumor microenvironment-responsive engineered hybrid nanomedicine for photodynamic-immunotherapy via multi-pronged amplification of reactive oxygen species

Reactive oxygen species (ROS) is promising in cancer therapy by accelerating tumor cell death, whose therapeutic efficacy, however, is greatly limited by the hypoxia in the tumor microenvironment (TME) and the antioxidant defense. Amplification of oxidative stress has been successfully employed for tumor therapy, but the interactions between cancer cells and the other factors of TME usually lead to inadequate tumor treatments. To tackle this issue, we develop a pH/redox dual-responsive nanomedicine based on the remodeling of cancer-associated fibroblasts (CAFs) for multi-pronged amplification of ROS (ZnPP@FQOS). It is demonstrated that ROS generated by ZnPP@FQOS is endogenously/exogenously multiply amplified owing to the CAFs remodeling and down-regulation of anti-oxidative stress in cancer cells, ultimately achieving the efficient photodynamic therapy in a female tumor-bearing mouse model. More importantly, ZnPP@FQOS is verified to enable the stimulation of enhanced immune responses and systemic immunity. This strategy remarkably potentiates the efficacy of photodynamic-immunotherapy, thus providing a promising enlightenment for tumor therapy.

Current advances in nanozyme-based nanodynamic therapies for cancer

Nanozymes are nano-catalysis materials with enzyme-like activities, which can repair the defects of natural enzyme such as harsh catalytic conditions, and harness their strengths to treat tumor. The emerging nanodynamic therapies improved drug selectivity and decreased drug tolerance, while causing efficient cell apoptosis through the generated reactive oxygen species (ROS). Nanodynamic therapies based on nanozymes can improve the complicated tumor microenvironment (TME) to reduce the defect rate of nanodynamic therapies, and provide more options for tumor treatment. This review summarized the characteristics and applications of nanozymes with different activities and the factors influencing the activity of nanozymes. We also focused on the application of nanozymes in nanodynamic therapies, including photodynamic therapy (PDT), chemodynamic therapy (CDT), and sonodynamic therapy (SDT). Moreover, we discussed the strategies for optimizing nanodynamic therapies based on nanozymes for tumor treatment in detail, and provided a systematic review of tactics for synergies with other tumor therapies. Ultimately, we analyzed the shortcomings of nanodynamic therapies based on nanozymes and the relevant research prospect, which would provide sufficient evidence and lay a foundation for further research. STATEMENT OF SIGNIFICANCE: 1. The novelty and significance of the work with respect to the existing literatures. (1) Recent advances in nanozyme-based nanodynamic therapies are comprehensively and systematically reviewed, and strategies to address the limitations and challenges of current therapies based on nanozymes are discussed firstly. (2) The mechanism of nanozymes in nanodynamic therapies is described for the first time. The synergistic therapies, prospects, and challenges of nanozyme-based nanodynamic therapies are innovatively discussed. 2. The scientific impact and interest to our readership. This review focuses on the recent progress of nanozyme-based nanodynamic therapies. This review indicates the way forward for the combined treatment of nanozymes and nanodynamic therapies, and lays a foundation for facilitating theoretical development in clinic.

Resveratrol suppresses liver cancer progression by downregulating AKR1C3: targeting HCC with HSA nanomaterial as a carrier to enhance therapeutic efficacy

The enzyme AKR1C3 plays a crucial role in hormone and drug metabolism and is associated with abnormal expression in liver cancer, leading to tumor progression and poor prognosis. Nanoparticles modified with HSA can modulate the tumor microenvironment by enhancing photodynamic therapy to induce apoptosis in tumor cells and alleviate hypoxia. Therefore, exploring the potential regulatory mechanisms of resveratrol on AKR1C3 through the construction of HSA-RSV NPs carriers holds significant theoretical and clinical implications for the treatment of liver cancer. The aim of this study is to investigate the targeted regulation of AKR1C3 expression through the loading of resveratrol (RSV) on nanomaterials HSA-RSV NPs (Nanoparticles) in order to alleviate tumor hypoxia and inhibit the progression of hepatocellular carcinoma (HCC), and to explore its molecular mechanism. PubChem database and PharmMapper server were used to screen the target genes of RSV. HCC-related differentially expressed genes (DEGs) were analyzed through the GEO dataset, and relevant genes were retrieved from the GeneCards database, resulting in the intersection of the three to obtain candidate DEGs. GO and KEGG enrichment analyses were performed on the candidate DEGs to analyze the potential cellular functions and molecular signaling pathways affected by the main target genes. The cytohubba plugin was used to screen the top 10 target genes ranked by Degree and further intersected the results of LASSO and Random Forest (RF) to obtain hub genes. The expression analysis of hub genes and the prediction of malignant tumor prognosis were conducted. Furthermore, a pharmacophore model was constructed using PharmMapper. Molecular docking simulations were performed using AutoDockTools 1.5.6 software, and ROC curve analysis was performed to determine the core target. In vitro cell experiments were carried out by selecting appropriate HCC cell lines, treating HCC cells with different concentrations of RSV, or silencing or overexpressing AKR1C3 using lentivirus. CCK-8, clone formation, flow cytometry, scratch experiment, and Transwell were used to measure cancer cell viability, proliferation, migration, invasion, and apoptosis, respectively. Cellular oxygen consumption rate was analyzed using the Seahorse XF24 analyzer. HSA-RSV NPs were prepared, and their characterization and cytotoxicity were evaluated. The biological functional changes of HCC cells after treatment were detected. An HCC subcutaneous xenograft model was established in mice using HepG2 cell lines. HSA-RSV NPs were injected via the tail vein, with a control group set, to observe changes in tumor growth, tumor targeting of NPs, and biological safety. TUNEL, Ki67, and APC-hypoxia probe staining were performed on excised tumor tissue to detect tumor cell proliferation, apoptosis, and hypoxia. Lentivirus was used to silence or overexpress AKR1C3 simultaneously with the injection of HSA-RSV NPs via the tail vein to assess the impact of AKR1C3 on the regulation of HSA-RSV NPs in HCC progression. Bioinformatics analysis revealed that AKR1C3 is an important target gene involved in the regulation of HCC by RSV, which is associated with the prognosis of HCC patients and upregulated in expression. In vitro cell experiments showed that RSV significantly inhibits the respiratory metabolism of HCC cells, suppressing their proliferation, migration, and invasion and promoting apoptosis. Silencing AKR1C3 further enhances the toxicity of RSV towards HCC cells. The characterization and cytotoxicity experiments of nanomaterials demonstrated the successful construction of HSA-RSV NPs, which exhibited stronger inhibitory effects on HCC cells. In vivo, animal experiments further confirmed that targeted downregulation of AKR1C3 by HSA-RSV NPs suppresses the progression of HCC and tumor hypoxia while exhibiting tumor targeting and biological safety. Targeted downregulation of AKR1C3 by HSA-RSV NPs can alleviate HCC tumor hypoxia and inhibit the progression of HCC.

Gas Therapy: Generating, Delivery, and Biomedical Applications

Oxygen (O2), nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S), and hydrogen (H2) with direct effects, and carbon dioxide (CO2) with complementary effects on the condition of various diseases are known as therapeutic gases. The targeted delivery and in situ generation of these therapeutic gases with controllable release at the site of disease has attracted attention to avoid the risk of gas poisoning and improve their performance in treating various diseases such as cancer therapy, cardiovascular therapy, bone tissue engineering, and wound healing. Stimuli-responsive gas-generating sources and delivery systems based on biomaterials that enable on-demand and controllable release are promising approaches for precise gas therapy. This work highlights current advances in the design and development of new approaches and systems to generate and deliver therapeutic gases at the site of disease with on-demand release behavior. The performance of the delivered gases in various biomedical applications is then discussed.

Folic Acid Functionalized AQ4N/Gd@PDA Nanoplatform with Real-Time Monitoring of Hypoxia Relief and Enhanced Synergistic Chemo/Photothermal Therapy in Glioma

Purpose

Hypoxia is often associated with glioma chemoresistance, and alleviating hypoxia is also crucial for improving treatment efficacy. However, although there are already some methods that can improve efficacy by alleviating hypoxia, real-time monitoring that can truly achieve hypoxia relief and efficacy feedback still needs to be explored.

Methods

AQ4N/Gd@PDA-FA nanoparticles (AGPF NPs) were synthesized using a one-pot method and were characterized. The effects of AGPF NPs on cell viability, cellular uptake, and apoptosis were investigated using the U87 cell line. Moreover, the effectiveness of AGPF NPs in alleviating hypoxia was explored in tumor-bearing mice through photoacoustic imaging. In addition, the diagnosis and treatment effect of AGPF NPs were evaluated by magnetic resonance imaging (MRI) and bioluminescent imaging (BLI) on orthotopic glioma mice respectively.

Results

In vitro experiments showed that AGPF NPs had good dispersion, stability, and controlled release. AGPF NPs were internalized by cells through endocytosis, and could significantly reduce the survival rate of U87 cells and increase apoptosis under irradiation. In addition, we monitored blood oxygen saturation at the tumor site in real-time through photoacoustic imaging (PAI), and the results showed that synergistic mild-photothermal therapy/chemotherapy effectively alleviated tumor hypoxia. Finally, in vivo anti-tumor experiments have shown that synergistic therapy can effectively alleviate hypoxia and inhibit the growth of orthotopic gliomas.

Conclusion

This work not only provides an effective means for real-time monitoring of the dynamic feedback between tumor hypoxia relief and therapeutic efficacy, but also offers a potential approach for the clinical treatment of gliomas.

Recent Advances in Reprogramming Strategy of Tumor Microenvironment for Rejuvenating Photosensitizers-Mediated Photodynamic Therapy

Photodynamic therapy (PDT) has recently been considered a potential tumor therapy due to its time-space specificity and non-invasive advantages. PDT can not only directly kill tumor cells by using cytotoxic reactive oxygen species but also induce an anti-tumor immune response by causing immunogenic cell death of tumor cells. Although it exhibits a promising prospect in treating tumors, there are still many problems to be solved in its practical application. Tumor hypoxia and immunosuppressive microenvironment seriously affect the efficacy of PDT. The hypoxic and immunosuppressive microenvironment is mainly due to the abnormal vascular matrix around the tumor, its abnormal metabolism, and the influence of various immunosuppressive-related cells and their expressed molecules. Thus, reprogramming the tumor microenvironment (TME) is of great significance for rejuvenating PDT. This article reviews the latest strategies for rejuvenating PDT, from regulating tumor vascular matrix, interfering with tumor cell metabolism, and reprogramming immunosuppressive related cells and factors to reverse tumor hypoxia and immunosuppressive microenvironment. These strategies provide valuable information for a better understanding of the significance of TME in PDT and also guide the development of the next-generation multifunctional nanoplatforms for PDT.

Nanomedicine Strategies in Conquering and Utilizing the Cancer Hypoxia Environment

Cancer with a complex pathological process is a major disease to human welfare. Due to the imbalance between oxygen (O2) supply and consumption, hypoxia is a natural characteristic of most solid tumors and an important obstacle for cancer therapy, which is closely related to tumor proliferation, metastasis, and invasion. Various strategies to exploit the feature of tumor hypoxia have been developed in the past decade, which can be used to alleviate tumor hypoxia, or utilize the hypoxia for targeted delivery and diagnostic imaging. The strategies to alleviate tumor hypoxia include delivering O2, in situ O2 generation, reprogramming the tumor vascular system, decreasing O2 consumption, and inhibiting HIF-1 related pathways. On the other side, hypoxia can also be utilized for hypoxia-responsive chemical construction and hypoxia-active prodrug-based strategies. Taking advantage of hypoxia in the tumor region, a number of methods have been applied to identify and keep track of changes in tumor hypoxia. Herein, we thoroughly review the recent progress of nanomedicine strategies in both conquering and utilizing hypoxia to combat cancer and put forward the prospect of emerging nanomaterials for future clinical transformation, which hopes to provide perspectives in nanomaterials design.

Unimolecular Self-Assembled Hemicyanine-Oleic Acid Conjugate Acts as a Novel Succinate Dehydrogenase Inhibitor to Amplify Photodynamic Therapy and Eliminate Cancer Stem Cells

Photodynamic therapy with reactive oxygen species production is a prospective treatment to combat cancer stem cells (CSCs). However, the innate drawbacks, including short lifetime and diffusion distance of reactive oxygen species and hypoxia within solid tumors, have become bottlenecks for clinical applications of photodynamic therapy. Here, we develop a mitochondria-targeting hemicyanine-oleic acid conjugate (CyOA), which can self-assemble into supramolecular nanoparticles (NPs) without any exogenous excipients. CyOA is also shown for targeting the mitochondrial complex II protein succinate dehydrogenase to inhibit oxidative phosphorylation and reverse tumor hypoxia, resulting in 50.4-fold higher phototoxicity against breast cancer stem cells (BCSCs) compared to SO3-CyOA NPs that cannot target to mitochondria. In 4T1 and BCSC tumor models, CyOA NPs achieve higher tumor inhibition and less lung metastasis nodules compared to the clinically used photosensitizer Hiporfin. This study develops a self-assembled small molecule that can serve as both oxidative phosphorylation inhibitor and photosensitizer for eradication of CSCs and treatment of solid tumors.

Fe-involved nanostructures act as photothermal transduction agents in cancer photothermal therapy

Cancer, a disease notorious for its difficult therapy regimen, has long puzzled researchers. Despite attempts to cure cancer using surgery, chemotherapy, radiotherapy, and immunotherapy, their effectiveness is limited. Recently, photothermal therapy (PTT), a rising strategy, has gained attention. PTT can increase the surrounding temperature of cancer tissues and cause damage to them. Fe is widely used in PTT nanostructures due to its strong chelating ability, good biocompatibility, and the potential to induce ferroptosis. In recent years, many nanostructures incorporating Fe3+ have been developed. In this article, we summarize PTT nanostructures containing Fe and introduce their synthesis and therapy strategy. However, PTT nanostructures containing Fe are still in their infancy, and more effort must be devoted to improving their effectiveness so that they can eventually be used in clinics.

Modulating tumor mechanics with nanomedicine for cancer therapy

Over the past several decades, the importance of the tumor mechanical microenvironment (TMME) in cancer progression or cancer therapy has been recognized by researchers worldwide. The abnormal mechanical properties of tumor tissues include high mechanical stiffness, high solid stress, and high interstitial fluid pressure (IFP), which form physical barriers resulting in suboptimal treatment efficacy and resistance to different types of therapy by preventing drugs infiltrating the tumor parenchyma. Therefore, preventing or reversing the establishment of the abnormal TMME is critical for cancer therapy. Nanomedicines can enhance drug delivery by exploiting the enhanced permeability and retention (EPR) effect, so nanomedicines that target and modulate the TMME can further boost antitumor efficacy. Herein, we mainly discuss the nanomedicines that can regulate mechanical stiffness, solid stress, and IFP, with a focus on how nanomedicines change abnormal mechanical properties and facilitate drug delivery. We first introduce the formation, characterizing methods and biological effects of tumor mechanical properties. Conventional TMME modulation strategies will be briefly summarized. Then, we highlight representative nanomedicines capable of modulating the TMME for augmented cancer therapy. Finally, current challenges and future opportunities for regulating the TMME with nanomedicines will be provided.

Nanotechnological strategies to increase the oxygen content of the tumor

Hypoxia is a negative prognostic indicator of solid tumors, which not only changes the survival state of tumors and increases their invasiveness but also remarkably reduces the sensitivity of tumors to treatments such as radiotherapy, chemotherapy and photodynamic therapy. Thus, developing therapeutic strategies to alleviate tumor hypoxia has recently been considered an extremely valuable target in oncology. In this review, nanotechnological strategies to elevate oxygen levels in tumor therapy in recent years are summarized, including (I) improving the hypoxic tumor microenvironment, (II) oxygen delivery to hypoxic tumors, and (III) oxygen generation in hypoxic tumors. Finally, the challenges and prospects of these nanotechnological strategies for alleviating tumor hypoxia are presented.