Stepwise dual targeting and dual responsive polymer micelles for mitochondrion therapy

Mechanisms of myocardial toxicity of antitumor drugs and potential therapeutic strategies: A review of the literature

With the successive development of chemotherapy drugs, good results have been achieved in clinical application. However, myocardial toxicity is the biggest challenge. Anthracyclines, immune checkpoint inhibitors, and platinum drugs are widely used. Targeted drug delivery, nanomaterials and dynamic imaging evaluation are all emerging research directions. This article reviews the recent literature on the use of targeted nanodrug delivery and imaging techniques to evaluate the myocardial toxicity of antineoplastic drugs, and discusses the potential mechanisms.

Molecular engineering to elevate reactive oxygen species generation for synergetic damage on lipid droplets and mitochondria

Photodynamic therapy (PDT), characterized by high treatment efficiency, absence of drug resistance, minimal trauma, and few side effects, has gradually emerged as a novel and alternative clinical approach compared to traditional surgical resection, chemotherapy and radiation. Whereas, considering the limited diffusion distance and short lifespan of reactive oxygen species (ROS), as well as the hypoxic tumor microenvironment, it is crucial to design photosensitizers (PSs) with suborganelle specific targeting ability and low-oxygen dependence for accurate and highly efficient photodynamic therapy. In this study, we have meticulously designed three PSs, namely CIH, CIBr, and CIPh, based on molecular engineering. Theoretical calculation demonstrate that the three compounds possess good molecular planarity with calculated S1-T1 energy gaps (ΔES1-T1) of 1.04 eV for CIH, 0.92 eV for CIBr, and 0.84 eV for CIPh respectively. Notably, CIPh showcases remarkable dual subcellular targeting capability towards lipid droplets (LDs) and mitochondria owing to the synergistic effect of lipophilicity derived from coumarin's inherent properties combined with electropositivity conferred by indole salt cations. Furthermore, CIPh demonstrates exclusive release of singlet oxygen (1O2)and highly efficient superoxide anion free radicals(O2⦁-) upon light irradiation supported by its smallest S1-T1 energy gap (ΔES1-T1 = 0.84 eV). This leads to compromised integrity of LDs along with mitochondrial membrane potential, resulting in profound apoptosis induction in HepG2 cells. This successful example of molecular engineering guided by density functional theory (DFT) provides valuable experience for the development of more effective PSs with superior dual targeting specificity. It also provides a new idea for the development of advanced PSs with efficient and accurate ROS generation ability towards fluorescence imaging-guided hypoxic tumor therapy.

Unlocking the Mitochondria for Nanomedicine-based Treatments: Overcoming Biological Barriers, Improving Designs, and Selecting Verification Techniques

Enhanced targeting approaches will support the treatment of diseases associated with dysfunctional mitochondria, which play critical roles in energy generation and cell survival. Obstacles to mitochondria-specific targeting include the presence of distinct biological barriers and the need to pass through (or avoid) various cell internalization mechanisms. A range of studies have reported the design of mitochondrially-targeted nanomedicines that navigate the complex routes required to influence mitochondrial function; nonetheless, a significant journey lies ahead before mitochondrially-targeted nanomedicines become suitable for clinical use. Moving swiftly forward will require safety studies, in vivo assays confirming effectiveness, and methodologies to validate mitochondria-targeted nanomedicines' subcellular location/activity. From a nanomedicine standpoint, we describe the biological routes involved (from administration to arrival within the mitochondria), the features influencing rational design, and the techniques used to identify/validate successful targeting. Overall, rationally-designed mitochondria-targeted-based nanomedicines hold great promise for precise subcellular therapeutic delivery.

Clickable X-ray Nanoprobes for Nanoscopic Bioimaging of Cellular Structures

Synchrotron-based X-ray microscopy (XRM) has garnered widespread attention from researchers due to its high spatial resolution and excellent energy (element) resolution. Existing molecular probes suitable for XRM include immune probes and genetic labeling probes, enabling the precise imaging of various biological targets within cells. However, immune labeling techniques are prone to cross-interference between antigens and antibodies. Genetic labeling technologies have limited systems that allow express markers independently, and moreover, genetically encoded labels based on catalytic polymerization lack a fixed morphology. When applied to cell imaging, this can result in reduced localization accuracy due to the diffusion of labels within the cells. Therefore, both techniques face challenges in simultaneously labeling multiple biotargets within cells and achieving high-precision imaging. In this work, we applied the click reaction and developed a third category of imaging probes suitable for XRM, termed clickable X-ray nanoprobes (Click-XRN). Click-XRN consists of two components: an X-ray-sensitive multicolor imaging module and a particle-size-controllable morphology module. Efficient identification of intra- and extracellular biotargets is achieved through click reactions between the probe and biomolecules. Click-XRN possesses a controllable particle size, and its loading of various metal ions provides distinctive signals for imaging under XRM. Based on this, we optimized the imaging energy of Click-XRN with different particle sizes, enabling single-color and two-color imaging of the cell membrane, cell nucleus, and mitochondria with nanoscale spatial nanometers. Our work provides a potent molecular tool for investigating cellular activities through XRM.

Chitosan-functionalized bioplatforms and hydrogels in breast cancer: immunotherapy, phototherapy and clinical perspectives

Breast cancer is the most common and malignant tumor among women. Chitosan (CS)-based nanoparticles have been introduced into breast cancer therapy as a way to increase the targeted delivery of drugs and genes to the tumor site. CS nanostructures suppress tumorigenesis by enhancing both the targeted delivery of cargo (drug and gene) and its accumulation in tumor cells. The tumor cells internalize CS-based nanoparticles through endocytosis. Moreover, chitosan nanocarriers can also induce phototherapy-mediated tumor ablation. Smart and multifunctional types of CS nanoparticles, including pH-, light- and redox-responsive nanoparticles, can be used to improve the potential for breast cancer removal. In addition, the acceleration of immunotherapy by CS nanoparticles has also been achieved, and there is potential to develop CS-nanoparticle hydrogels that can be used to suppress tumorigenesis.

Marine biomaterials in biomedical nano/micro-systems

Marine resources in unique marine environments provide abundant, cost-effective natural biomaterials with distinct structures, compositions, and biological activities compared to terrestrial species. These marine-derived raw materials, including polysaccharides, natural protein components, fatty acids, and marine minerals, etc., have shown great potential in preparing, stabilizing, or modifying multifunctional nano-/micro-systems and are widely applied in drug delivery, theragnostic, tissue engineering, etc. This review provides a comprehensive summary of the most current marine biomaterial-based nano-/micro-systems developed over the past three years, primarily focusing on therapeutic delivery studies and highlighting their potential to cure a variety of diseases. Specifically, we first provided a detailed introduction to the physicochemical characteristics and biological activities of natural marine biocomponents in their raw state. Furthermore, the assembly processes, potential functionalities of each building block, and a thorough evaluation of the pharmacokinetics and pharmacodynamics of advanced marine biomaterial-based systems and their effects on molecular pathophysiological processes were fully elucidated. Finally, a list of unresolved issues and pivotal challenges of marine-derived biomaterials applications, such as standardized distinction of raw materials, long-term biosafety in vivo, the feasibility of scale-up, etc., was presented. This review is expected to serve as a roadmap for fundamental research and facilitate the rational design of marine biomaterials for diverse emerging applications.

Unleashing novel horizons in advanced prostate cancer treatment: investigating the potential of prostate specific membrane antigen-targeted nanomedicine-based combination therapy

Prostate cancer (PCa) is a prevalent malignancy with increasing incidence in middle-aged and older men. Despite various treatment options, advanced metastatic PCa remains challenging with poor prognosis and limited effective therapies. Nanomedicine, with its targeted drug delivery capabilities, has emerged as a promising approach to enhance treatment efficacy and reduce adverse effects. Prostate-specific membrane antigen (PSMA) stands as one of the most distinctive and highly selective biomarkers for PCa, exhibiting robust expression in PCa cells. In this review, we explore the applications of PSMA-targeted nanomedicines in advanced PCa management. Our primary objective is to bridge the gap between cutting-edge nanomedicine research and clinical practice, making it accessible to the medical community. We discuss mainstream treatment strategies for advanced PCa, including chemotherapy, radiotherapy, and immunotherapy, in the context of PSMA-targeted nanomedicines. Additionally, we elucidate novel treatment concepts such as photodynamic and photothermal therapies, along with nano-theragnostics. We present the content in a clear and accessible manner, appealing to general physicians, including those with limited backgrounds in biochemistry and bioengineering. The review emphasizes the potential benefits of PSMA-targeted nanomedicines in enhancing treatment efficiency and improving patient outcomes. While the use of PSMA-targeted nano-drug delivery has demonstrated promising results, further investigation is required to comprehend the precise mechanisms of action, pharmacotoxicity, and long-term outcomes. By meticulous optimization of the combination of nanomedicines and PSMA ligands, a novel horizon of PSMA-targeted nanomedicine-based combination therapy could bring renewed hope for patients with advanced PCa.

Unleashing novel horizons in advanced prostate cancer treatment: investigating the potential of prostate specific membrane antigen-targeted nanomedicine-based combination therapy

Prostate cancer (PCa) is a prevalent malignancy with increasing incidence in middle-aged and older men. Despite various treatment options, advanced metastatic PCa remains challenging with poor prognosis and limited effective therapies. Nanomedicine, with its targeted drug delivery capabilities, has emerged as a promising approach to enhance treatment efficacy and reduce adverse effects. Prostate-specific membrane antigen (PSMA) stands as one of the most distinctive and highly selective biomarkers for PCa, exhibiting robust expression in PCa cells. In this review, we explore the applications of PSMA-targeted nanomedicines in advanced PCa management. Our primary objective is to bridge the gap between cutting-edge nanomedicine research and clinical practice, making it accessible to the medical community. We discuss mainstream treatment strategies for advanced PCa, including chemotherapy, radiotherapy, and immunotherapy, in the context of PSMA-targeted nanomedicines. Additionally, we elucidate novel treatment concepts such as photodynamic and photothermal therapies, along with nano-theragnostics. We present the content in a clear and accessible manner, appealing to general physicians, including those with limited backgrounds in biochemistry and bioengineering. The review emphasizes the potential benefits of PSMA-targeted nanomedicines in enhancing treatment efficiency and improving patient outcomes. While the use of PSMA-targeted nano-drug delivery has demonstrated promising results, further investigation is required to comprehend the precise mechanisms of action, pharmacotoxicity, and long-term outcomes. By meticulous optimization of the combination of nanomedicines and PSMA ligands, a novel horizon of PSMA-targeted nanomedicine-based combination therapy could bring renewed hope for patients with advanced PCa.

Preclinical evaluation of Mito-LND, a targeting mitochondrial metabolism inhibitor, for glioblastoma treatment

BACKGROUND

Glioblastoma (GBM) is a brain tumor with the highest level of malignancy and the worst prognosis in the central nervous system. Mitochondrial metabolism plays a vital role in the occurrence and development of cancer, which provides critical substances to support tumor anabolism. Mito-LND is a novel small-molecule inhibitor that can selectively inhibit the energy metabolism of tumor cells. However, the therapeutic effect of Mito-LND on GBM remains unclear.

METHODS

The present study evaluated the inhibitory effect of Mito-LND on the growth of GBM cells and elucidated its potential mechanism.

RESULTS

The results showed that Mito-LND could inhibit the survival, proliferation and colony formation of GBM cells. Moreover, Mito-LND induced cell cycle arrest and apoptosis. Mechanistically, Mito-LND inhibited the activity of mitochondrial respiratory chain complex I and reduced mitochondrial membrane potential, thus promoting ROS generation. Importantly, Mito-LND could inhibit the malignant proliferation of GBM by blocking the Raf/MEK/ERK signaling pathway. In vivo experiments showed that Mito-LND inhibited the growth of GBM xenografts in mice and significantly prolonged the survival time of tumor-bearing mice.

CONCLUSION

Taken together, the current findings support that targeting mitochondrial metabolism may be as a potential and promising strategy for GBM therapy, which will lay the theoretical foundation for further clinical trials on Mito-LND in the future.

Peptide-modified bioresponsive chondroitin sulfate micelles for targeted doxorubicin delivery in triple-negative breast cancer

Triple-negative breast cancer is an offensive tumor that is highly challenging to cure. In this study, we developed novel polymeric nanoparticles that target dual receptors and respond to reducing conditions for chemotherapeutic drug release in the treatment of triple-negative breast cancer. Then we synthesized and characterized a targeted peptide-grafted chondroitin sulfate A-ss-deoxycholic acid (TCSSD) copolymer and prepare doxorubicin (DOX)-loaded TCSSD (TCSSD-D) micelles high-loading content. The bioresponsive drug release of TCSSD-D nanoparticles was demonstrated in a glutathione-containing phosphate buffer solution. We found that TCSSD-D effectively targeted CD44 and P-selectin receptors both in vitro and in vivo. TCSSD-D micelles were higher cytotoxicity and cellular uptake than unmodified DOX-containing micelles in MDA-MB-231 cells. Furthermore, TCSSD-D micelles showed the strongest suppression of tumor growth among three DOX-based formulations in triple-negative MDA-MB-231-bearing nude mice. These results suggest that amphiphilic TCSSD nanoparticles can serve as a targeted and intelligent delivery vehicle for triple-negative breast cancer therapy.

Smart Chondroitin Sulfate Micelles for Effective Targeted Delivery of Doxorubicin Against Breast Cancer Metastasis

Introduction

Metastasis is a major challenge in breast cancer therapy. The successful chemotherapy of breast cancer largely depends on the ability to block the metastatic process. Herein, we designed a dual-targeting and stimuli-responsive drug delivery system for targeted drug delivery against breast cancer metastasis.

Methods

AS1411 aptamer-modified chondroitin sulfate A-ss-deoxycholic acid (ACSSD) was synthesized, and the unmodified CSSD was used as the control. Chemotherapeutic drug doxorubicin (DOX)-containing ACSSD (D-ACSSD) micelles were prepared by a dialysis method. The ACSSD conjugate was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and transmission electron microscopy (TEM). In vitro cellular uptake and cytotoxicity of D-ACSSD micelles were studied by confocal laser scanning microscopy (CLSM) and MTT assay in breast tumor cells. The inhibition capability of D-ACSSD micelles in cell migration and invasion was carried out in 4T1 cells. In vivo antitumor activity of DOX-containing micelles was investigated in metastatic 4T1-bearing Balb/c mice.

Results

D-ACSSD and DOX-loaded CSSD (D-CSSD) micelles exhibited high drug encapsulation content and reduction-responsive characteristics. D-ACSSD micelles were spherical in shape. Compared with D-CSSD, D-ACSSD showed higher cellular uptake and more potent killing activity in 4T1 and MDA-MB-231 cells. Additionally, D-ACSSD exhibited stronger inhibitory effects on the invasion and migration of highly metastatic 4T1 cells than unmodified D-CSSD. Among the DOX-containing formulations, D-ACSSD micelles presented the most effective inhibition of tumor growth and lung metastasis in orthotopic 4T1-bearing mice in vivo. It also revealed that ACSSD micelles did not exhibit obvious systemic toxicity.

Conclusion

The smart D-ACSSD micelles could be a promising delivery system for the therapy of metastatic breast cancer.

Dual tumor- and subcellular-targeted photodynamic therapy using glucose-functionalized MoS2 nanoflakes for multidrug-resistant tumor ablation

Photodynamic therapy (PDT) is emerging as an efficient strategy to combat multidrug-resistant (MDR) cancer. However, the short half-life and limited diffusion of reactive oxygen species (ROS) undermine the therapeutic outcomes of this therapy. To address this issue, a tumor-targeting nanoplatform was developed to precisely deliver mitochondria- and endoplasmic reticulum (ER)-targeting PDT agents to desired sites for dual organelle-targeted PDT. The nanoplatform is constructed by functionalizing molybdenum disulfide (MoS₂) nanoflakes with glucose-modified hyperbranched polyglycerol (hPG), and then loading the organelle-targeting PDT agents. The resultant nanoplatform Cy7.5-TG@GPM is demonstrated to mediate both greatly enhanced internalization within MDR cells and precise subcellular localization of PDT agents, facilitating in situ near-infrared (NIR)-triggered ROS generation for augmented PDT and reversal of MDR, causing impressive tumor shrinkage in a HeLa multidrug-resistant tumor mouse model. As revealed by mechanistic studies of the synergistic mitochondria- and ER-targeted PDT, ROS-induced ER stress not only activates the cytosine-cytosine-adenosine-adenosine thymidine/enhancer-binding protein homologous protein (CHOP) pro-apoptotic signaling pathway, but also cooperates with ROS-induced mitochondrial dysfunction to trigger cytochrome C release from the mitochondria and induce subsequent cell death. Furthermore, the mitochondrial dysfunction reduces ATP production and thereby contributes to the reversal of MDR. This nanoplatform, with its NIR-responsive properties and ability to target tumors and subcellular organelles, offers a promising strategy for effective MDR cancer therapy.

Current progress of nanomedicine for prostate cancer diagnosis and treatment

Prostate cancer (PCa) is the most common new cancer case and the second most fatal malignancy in men. Surgery, endocrine therapy, radiotherapy and chemotherapy are the main clinical treatment options for PCa. However, most prostate cancers can develop into castration-resistant prostate cancer (CRPC), and due to the invasiveness of prostate cancer cells, they become resistant to different treatments and activate tumor-promoting signaling pathways, thereby inducing chemoresistance, radioresistance, ADT resistance, and immune resistance. Nanotechnology, which can combine treatment with diagnostic imaging tools, is emerging as a promising treatment modality in prostate cancer therapy. Nanoparticles can not only promote their accumulation at the pathological site through passive targeting techniques for enhanced permeability and retention (EPR), but also provide additional advantages for active targeting using different ligands. This property results in a reduced drug dose to achieve the desired effect, a longer duration of action within the tumor and fewer side effects on healthy tissues. In addition, nanotechnology can create good synergy with radiotherapy, chemotherapy, thermotherapy, photodynamic therapy and gene therapy to enhance their therapeutic effects with greater scope, and reduce the resistance of prostate cancer. In this article, we intend to review and discuss the latest technologies regarding the use of nanomaterials as therapeutic and diagnostic tools for prostate cancer.

Progress in Polymeric Micelles for Drug Delivery Applications

Polymeric micelles (PMs) have made significant progress in drug delivery applications. A robust core-shell structure, kinetic stability and the inherent ability to solubilize hydrophobic drugs are the highlights of PMs. This review presents the recent advances and understandings of PMs with a focus on the latest drug delivery applications. The types, methods of preparation and characterization of PMs are described along with their applications in oral, parenteral, transdermal, intranasal and other drug delivery systems. The applications of PMs for tumor-targeted delivery have been provided special attention. The safety, quality and stability of PMs in relation to drug delivery are also provided. In addition, advanced polymeric systems and special PMs are also reviewed. The in vitro and in vivo stability assessment of PMs and recent understandings in this area are provided. The patented PMs and clinical trials on PMs for drug delivery applications are considered indicators of their tremendous future applications. Overall, PMs can help overcome many unresolved issues in drug delivery.

Near-infrared fluorescent probes based on a quinoxaline skeleton for imaging nucleic acids in mitochondria

In this paper, two cationic probes 1a and 1b and a neutral dye 1c were successfully designed and synthesized according to the Knoevenagel condensation reaction, which combines the good optical properties of hemocyanine and the biocompatibility of nitrogen-containing heterocyclic rings based on a quinoxaline skeleton. Probes 1a and 1b showed an OFF-ON fluorescence response to nucleic acids with excellent selectivity. Specifically, the fluorescence intensity of probe 1a was enhanced by 18 and 133 times, respectively, along with the increase of DNA or RNA concentrations (0-600 μg mL^-1). Furthermore, a good linear correlation between the fluorescence intensity of probes 1a and 1b and the concentrations of DNA or RNA (0-350 μg mL^-1) was obtained. In particular, the maximum emission wavelengths of probes 1a and 1b reached the near-infrared region (660-664 nm) when DNA or RNA was detected, which might reduce the light damage to cells and facilitate cell experiments. Fluorescence imaging revealed that all three dyes could be localized in the mitochondria of HeLa cells. The difference was that probes 1a and 1b could stain the nucleic acid in the mitochondria, while dye 1c was only a neutral mitochondrial biomarker. The results indicated that probes 1a and 1b are promising in the development of low toxicity mitochondrial nucleic acid probes and are expected to be used in monitoring the normal state of mitochondrial nucleic acids for living cells, which will help improve the situation in that currently reported studies of fluorescent probes are mainly focused on the nucleic acids in the nucleus, but less so on DNA in the mitochondria.

Depleting Tumor Infiltrating B Cells to Boost Antitumor Immunity with Tumor Immune-Microenvironment Reshaped Hybrid Nanocage

Tumor infiltrating B cells (TIBs)-dependent immunotherapy has emerged as a promising method for tumor treatment. Depleting TIBs to boost antitumor immunity is a highly desirable yet challenging approach to TIBs-dependent immunotherapy. Herein, a tumor immune-microenvironment reshaped hybrid nanocage CPN-NLI/MLD coloaded with the Bruton's tyrosine kinase inhibitor ibrutinib, and cytotoxic drug docetaxel was developed for stepwise targeting TIBs and tumor cells, respectively. The tumor microenvironment responsive CPN-NLI/MLD promoted charge reversal and size reduction under acidic conditions (pH < 6.5). The accumulation of CPN-NLI/MLD in tumor tissues was achieved through CD13 targeting, and cellular uptake was increased due to the differ-targeting delivery. Targeting of docetaxel to tumor cells was achieved by the interaction of α-MSH modified on inner docetaxel-particle MLD and melanocortin-1 receptor on the surface of tumor cells. Targeting of ibrutinib to TIBs was achieved by the interaction of Neu5Ac modified on inner ibrutinib-particle NLI and CD22 on the surface of TIBs. The boosted antitumor immunity was achieved mainly by the inhibition of Bruton's tyrosine kinase activation mediated by ibrutinib, which reduced the proportion of TIBs, enhanced infiltration of CD8⁺ and CD4⁺ T cells, increased the secretion of immunogenic cytokines including IL-2 and IFN-γ, and inhibited the proliferation of regulatory T cells and secretion of immunosuppressive cytokines including IL-10, IL-4, and TGF-β. Furthermore, CPN-NLI/MLD improved the antitumor efficiency of chemoimmunotherapy by reshaping tumor immune-microenvironment by TIBs depletion. Taken together, CPN-NLI/MLD represents a promising method for effective tumor treatment and combination therapy by TIBs-dependent immunotherapy.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Effect of the disulfide bond and polyethylene glycol on the degradation and biophysicochemical properties of polyurethane micelles

The disulfide bond has emerged as a promising redox-sensitive switch for smart polymeric micelles, due to its properties of rapid response to the reductive environment and spatiotemporally-controlled therapeutic agent delivery. However, the dilemma of multifunctional nanomedicine is that the more intelligent the functionalities integrated into a system, the vaguer the understanding of the structure and interaction between the multi-functional moieties becomes. To better understand the interaction between the disulfide bond and methoxy polyethylene glycol (mPEG), and their effects on the biophysicochemical characterization of micelles, we developed a series of polyurethane micelles containing various densities of disulfide bonds and bearing different molecular weights of mPEG. In this work, we found that the critical factor determining the degradation rate of polymer micelles was the hydrophobic/hydrophilic ratio of broken polymer segments triggered by disulfide bond breaking. The higher density of the disulfide bond and longer mPEG chain accelerate the degradation process due to the disproportionate hydrophobic/hydrophilic ratio of the broken chain, which is the key factor to determine the micellization and stabilization of polymer micelles. This work provides a fundamental understanding of the interaction between the complex functional groups and a new insight into the mechanism of the micelle degradation process, offering guidance on the rational design and fabrication of multifunctional nanoformulations.

Multifunctional Mitochondria-Targeting Nanosystems for Enhanced Anticancer Efficacy

Mitochondria, a kind of subcellular organelle, play crucial roles in cancer cells as an energy source and as a generator of reactive substrates, which concern the generation, proliferation, drug resistance, and other functions of cancer. Therefore, precise delivery of anticancer agents to mitochondria can be a novel strategy for enhanced cancer treatment. Mitochondria have a four-layer structure with a high negative potential, which thereby prevents many molecules from reaching the mitochondria. Luckily, the advances in nanosystems have provided enormous hope to overcome this challenge. These nanosystems include liposomes, nanoparticles, and nanomicelles. Here, we summarize the very latest developments in mitochondria-targeting nanomedicines in cancer treatment as well as focus on designing multifunctional mitochondria-targeting nanosystems based on the latest nanotechnology.

Recent Progress in Polymeric AIE-Active Drug Delivery Systems: Design and Application

Aggregation-induced emission (AIE) provides a new opportunity to overcome the drawbacks of traditional aggregation-induced quenching of chromophores. The applications of AIE-active fluorophores have spread across various fields. In particular, the employment of AIEgens in drug delivery systems (DDSs) can achieve imaging-guided therapy and pharmacodynamic monitoring. As a result, polymeric AIE-active DDSs are attracting increasing attention due to their obvious advantages, including easy fabrication and tunable optical properties by molecular design. Additionally, the design of polymeric AIE-active DDSs is a promising method for cancer therapy, antibacterial treatment, and pharmacodynamic monitoring, which indeed helps improve the effectiveness of related disease treatments and confirms its potential social importance. Here, we summarize the current available polymeric AIE-active DDSs from design to applications. In the design section, we introduce synthetic strategies and structures of AIE-active polymers, as well as responsive strategies for specific drug delivery. In the application section, typical polymeric AIE-active DDSs used for cancer therapy, bacterial treatment, and drug delivery monitoring are summarized with selected examples to elaborate on their wide applications.

A Redox-Responsive Nanovaccine Combined with A2A Receptor Antagonist for Cancer Immunotherapy

In situ vaccination can trigger an antitumor immune response. However, the therapeutic effect is still limited since the high expression of adenosine binding to G protein-coupled receptor A2AR induces an immunosuppressive effect. In this work, a new formulation is presented with the combination of a nanovaccine based on redox-responsive polymer micelles and A2AR antagonist SCH58261. The micelles simultaneously encapsulate immunogenic cell death (ICD) inducer doxorubicin (DOX) and adjuvant toll-like receptor 7 and 8 (TLR7/8) agonist R848, acting as the potent in situ vaccines. A high concentration of glutathione in tumor cells leads to the disintegration of these micelles, releasing DOX and R848 to mediate ICD, inducing the activation of dendritic cells and initiating an immune response. Meanwhile, A2AR antagonist SCH58261, a generation immune checkpoint blocker, inhibits the immunosuppressive adenosinergic pathway in the tumor microenvironment, activating natural killer (NK) cells and CD8⁺ T cells, and inhibiting the proliferation of regulatory T cells. Therefore, this formulation can trigger a robust systemic antitumor immune response.

Recent advances in polymeric core-shell nanocarriers for targeted delivery of chemotherapeutic drugs

The treatment effect of chemotherapeutics is often impeded by nonspecific biodistribution and limited biocompatibility. Polymeric core-shell nanocarriers (PCS NCs) composed of a polymer core and at least one shell have been widely applied for cancer therapy and have shown great potential in selectively delivering chemotherapeutic drugs to tumor sites. These PCS NCs can effectively ameliorate the delivery efficiency and therapeutic index of anticarcinogens by prolonging drug residence in the bloodstream, enhancing tumor tissue drug penetration, facilitating cellular drug uptake, controlling the spatiotemporal release of payloads, or codelivering two or more bioactive agents. This review summarizes recently published literature on using PCS NCs to transport chemotherapeutic drugs with poor aqueous solubility and discusses their design principles, structural features, functional properties, and potential limitations.

S100A1 is Involved in Myocardial Injury Induced by Exhaustive Exercise

Many studies have confirmed that exhaustive exercise has adverse effects on the heart by generating reactive oxygen species (ROS). S100A1 calcium-binding protein A1 (S100A1) is a regulator of myocardial contractility and a protector against myocardial injury. However, few studies have investigated the role of S100A1 in the regulation of myocardial injury induced by exhaustive exercise. In the present study, we suggested that exhaustive exercise led to increased ROS, downregulation of S100a1, and myocardial injury. Downregulation of S100a1 promoted exhaustive exercise-induced myocardial injury and overexpression of S100A1 reversed oxidative stress-induced cardiomyocyte injury, indicating S100A1 is a protective factor against myocardial injury caused by exhaustive exercise. We also found that downregulation of S100A1 promoted damage to critical proteins of the mitochondria by inhibiting the expression of Ant1, Pgc1a, and Tfam under exhaustive exercise. Our study indicated S100A1 as a potential prognostic biomarker or therapeutic target to improve the myocardial damage induced by exhaustive exercise and provided new insights into the molecular mechanisms underlying the myocardial injury effect of exhaustive exercise.

Rational Design 2-Hydroxypropylphosphonium Salts as Cancer Cell Mitochondria-Targeted Vectors: Synthesis, Structure, and Biological Properties

It has been shown for a wide range of epoxy compounds that their interaction with triphenylphosphonium triflate occurs with a high chemoselectivity and leads to the formation of (2-hydroxypropyl)triphenylphosphonium triflates 3 substituted in the 3-position with an alkoxy, alkylcarboxyl group, or halogen, which were isolated in a high yield. Using the methodology for the disclosure of epichlorohydrin with alcohols in the presence of boron trifluoride etherate, followed by the substitution of iodine for chlorine and treatment with triphenylphosphine, 2-hydroxypropyltriphenylphosphonium iodides 4 were also obtained. The molecular and supramolecular structure of the obtained phosphonium salts was established, and their high antitumor activity was revealed in relation to duodenal adenocarcinoma. The formation of liposomal systems based on phosphonium salt 3 and L-α-phosphatidylcholine (PC) was employed for improving the bioavailability and reducing the toxicity. They were produced by the thin film rehydration method and exhibited cytotoxic properties. This rational design of phosphonium salts 3 and 4 has promising potential of new vectors for targeted delivery into mitochondria of tumor cells.

Mito-Bomb: Targeting Mitochondria for Cancer Therapy

Cancer has been one of the most common life-threatening diseases for a long time. Traditional cancer therapies such as surgery, chemotherapy (CT), and radiotherapy (RT) have limited effects due to drug resistance, unsatisfactory treatment efficiency, and side effects. In recent years, photodynamic therapy (PDT), photothermal therapy (PTT), and chemodynamic therapy (CDT) have been utilized for cancer treatment owing to their high selectivity, minor resistance, and minimal toxicity. Accumulating evidence has demonstrated that selective delivery of drugs to specific subcellular organelles can significantly enhance the efficiency of cancer therapy. Mitochondria-targeting therapeutic strategies are promising for cancer therapy, which is attributed to the essential role of mitochondria in the regulation of cancer cell apoptosis, metabolism, and more vulnerable to hyperthermia and oxidative damage. Herein, the rational design, functionalization, and applications of diverse mitochondria-targeting units, involving organic phosphine/sulfur salts, quaternary ammonium (QA) salts, peptides, transition-metal complexes, guanidinium or bisguanidinium, as well as mitochondria-targeting cancer therapies including PDT, PTT, CDT, and others are summarized. This review aims to furnish researchers with deep insights and hints in the design and applications of novel mitochondria-targeting agents for cancer therapy.

A pH-triggered fluorescence-switchable extracellular vesicle for tracing drug release and improving drug delivery

Extracellular vesicles have shown great potential in drug delivery for clinical applications. However, some obstacles still need to be overcome before their clinical translation, including on demand release of drugs to improve the efficacy and monitoring of the drug release process to ascertain drug dosage. Herein, a pH-triggered fluorescence-switchable extracellular vesicle as a smart nanocarrier is fabricated by loading zwitterionic fluorescent carbon dots (CDs) into macrophage cell-secreted vesicles to achieve improved drug delivery and real-time monitoring of drug release. When circulating in the blood, the zwitterionic CDs loaded in the vesicles can tightly bind the chemotherapeutic drug DOX through electrostatic interactions to avoid premature drug unload. The nanocarriers have a long blood circulation half-life of 15.12 h and a high tumor accumulation of 9.88% ID/g. Meanwhile, the fluorescence of the CDs is in the "off" state due to the fluorescence inner filter effect (IFE) between the DOX and the CDs. When the nanocarriers enter the tumor cells, the low pH of the lysosome leads to charge reversal of the CDs. DOX can be quickly released through electrostatic repulsion and the fluorescence of the CDs turns "on" after the release of the drugs, thus enabling an improved drug delivery and real-time tracking of the drug release process.

pH-activated, mitochondria-targeted, and redox-responsive delivery of paclitaxel nanomicelles to overcome drug resistance and suppress metastasis in lung cancer

Background

Mitochondria play a role in the occurrence, development, drug resistance, metastasis, and other functions of cancer and thus are a drug target. An acid-activated mitochondria-targeting drug nanocarrier with redox-responsive function was constructed in the present study. However, whether this vector can precisely delivery paclitaxel (PTX) to enhance therapeutic efficacy in drug-resistant lung cancer is unknown.

Results

Acid-cleavable dimethylmaleic anhydride (DA) was used to modify pluronic P85-conjugated mitochondria-targeting triphenylphosphonium (TPP) using disulfide bonds as intermediate linkers (DA-P85-SS-TPP and DA-P-SS-T). The constructed nanocarriers demonstrated enhanced cellular uptake and selective mitochondrial targeting at extracellular pH characteristic for a tumor (6.5) and were characterized by extended circulation in the blood. TPP promoted the targeting of the DA-P-SS-T/PTX nanomicelles to the mitochondrial outer membrane to decrease the membrane potential and ATP level, resulting in inhibition of P-glycoprotein and suppression of drug resistance and cancer metastasis. PTX was also rapidly released in the presence of high glutathione (GSH) levels and directly diffused into the mitochondria, resulting in apoptosis of drug-resistant lung cancer cells.

Conclusions

These promising results indicated that acid-activated mitochondria-targeting and redox-responsive nanomicelles potentially represent a significant advancement in cancer treatment.

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Synthetic infrared nano-photosensitizers with hierarchical zoom-in target-delivery functionalities for precision photodynamic therapy

Surgical assailment at the vulnerable subcellular organelles (e.g. mitochondria) by photodynamic therapy (PDT) is perceived as the most devastating approach to eradicate the tumors. Herein, we programmed a novel near-infrared (NIR) PDT construct illustrating appreciable hierarchical zoom-in targeting scenario, namely, primary cell-level targeting to carcinoma post systemic dosage and subcellular level targeting to mitochondria. Pertaining to tumor-targeting function, charge reversal chemistry selectively responsive to acidic tumoral microenvironments (pH 6.8) was implemented as the external corona of PDT constructs. This charge transformative exterior entitled minimal biointerfacial reactions in systemic retention but intimate affinities to cytomembranes selectively in tumoral microenvironments, thereby resulting in preferential uptake by tumors. Furthermore, the proposed PDT constructs were equipped with mitochondria targeting triphenylphosphonium (TPP) motif, which appeared to propel intriguing 88% colocalization with mitochondria. Therefore, overwhelming cytotoxic potencies were accomplished by our carefully engineered photodynamic constructs. Another noteworthy is the photodynamic constructs characterized to be excited at tissue-penetrating NIR (980 nm) based on energy transfer between their internal components of anti-Stoke upconversion nanoparticles (UCN, donor) and photodynamic chlorin e6 (Ce6, acceptor). Therefore, practical applications for photodynamic treatment of intractable solid carcinoma were greatly facilitated and complete tumor eradication was achieved by systemic administration of the ultimate multifunctional NIR photodynamic constructs.

Recent progress in nanomedicine for enhanced cancer chemotherapy

As one of the most important cancer treatment strategies, conventional chemotherapy has substantial side effects and leads easily to cancer treatment failure. Therefore, exploring and developing more efficient methods to enhance cancer chemotherapy is an urgently important problem that must be solved. With the development of nanotechnology, nanomedicine has showed a good application prospect in improving cancer chemotherapy. In this review, we aim to present a discussion on the significant research progress in nanomedicine for enhanced cancer chemotherapy. First, increased enrichment of drugs in tumor tissues relying on different targeting ligands and promoting tissue penetration are summarized. Second, specific subcellular organelle-targeted chemotherapy is discussed. Next, different combinational strategies to reverse multidrug resistance (MDR) and improve the effective intracellular concentration of therapeutics are discussed. Furthermore, the advantages of combination therapy for cancer treatment are emphasized. Finally, we discuss the major problems facing therapeutic nanomedicine for cancer chemotherapy, and propose possible future directions in this field.

Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives

The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.

Folic Acid-Modified Erythrocyte Membrane Loading Dual Drug for Targeted and Chemo-Photothermal Synergistic Cancer Therapy

To overcome the challenges of systemic toxicity and weak tumor selectivity caused by traditional antitumor drugs, numerous nanocarrier systems have been developed in recent decades, and their therapeutic effect has been improved to varying degrees. However, because of the drug resistance effect and metastasis involved in tumor recurrence, a single chemotherapy can no longer satisfy the diversified treatment needs. Recently, the application of chemotherapy in combination with thermotherapy as a synergistic approach has been proven to be more effective, and it provides a new strategy for cancer therapy. In this work, by utilizing the unique properties of erythrocytes, a surface-modified erythrocyte membrane was constructed as a novel nanocarrier system (DOX and ICG-PLGA@RBC nanoparticles, DIRNPs for short) for the simultaneous transportation of chemotherapeutic drugs (doxorubicin, DOX) and photothermal agents (indocyanine green, ICG) to achieve the effects of long-term circulation, active tumor targeting, and triggered drug release. The results indicated that DIRNPs have a nanoscale particle size of 158.4 nm with a narrow size distribution and a negative surface charge of -5.79 mV. No particle aggregation or remarkable drug leakage was observed during the 30 day storage test, and because of the excellent photothermal conversion ability of ICG, the local temperature of DIRNPs could dramatically increase from 33.7 to 49.8 °C in 10 min under near-infrared (NIR) laser irradiation. The in vitro drug dissolution data demonstrated that the DOX release from the DIRNPs was pH-dependent and NIR-triggered. Folic acid modifications of the erythrocyte membrane effectively facilitated the intracellular uptake of DIRNPs by HepG2 cells and, as a result, it significantly inhibited tumor cell growth, promoted reactive oxygen species levels, induced cell apoptosis, and restricted cell recovery and migration. In vivo pharmacokinetics and biodistribution studies indicated that the DIRNPs prolonged the half-life of DOX from 6.03 to 17.6 h and remarkably reduced the DOX level in the heart to avoid drug-related cardiotoxicity. More importantly, the DIRNPs exerted excellent in vivo antitumor efficacy against H22 tumors with superior safety. In conclusion, utilizing the advantageous properties of erythrocytes to construct a tumor-targeted biomimetic nanocarrier for codelivery of chemotherapeutics and photothermal agents to produce synergistic effects is considered an effective method for cancer therapy.

Cytochrome c light-up graphene oxide nanosensor for the targeted self-monitoring of mitochondria-mediated tumor cell death

Targeting mitochondria-mediated apoptosis has emerged as a promising strategy for tumor therapy. However, technologies used to treat tumors that enable the direct visualization of mitochondria-mediated apoptosis in living cells have not been developed to date. Cytochrome c (Cyt c) translocation from mitochondria is a central mediating event in cell apoptosis. In this study, we developed a multifunctional nanosensor that can monitor the real-time translocation of Cyt c from mitochondria in living cells to evaluate the antitumor effect of dihydroartemisinin (DHA). A fluorophore-tagged DNA aptamer is loaded on a graphene oxide (GO)-based nanovehicle, and the cytosolic release of Cyt c causes the dissociation of the aptamer from the GO nanovehicle and triggers the emission of a red fluorescence signal. Furthermore, DHA linked with a coumarin derivative is loaded on GO as a mitochondria-targeting ligand to improve its antitumor activity. This DHA prodrug also emits a green fluorescence signal when delivered to mitochondria. This nanosensor provides a convenient mechanism to monitor mitochondrial targeting by drugs and mitochondria-induced therapeutic efficacy, which may be possible to diagnose the drug efficacy to optimize the treatment for patients with cancer.

Advances in cell penetrating peptides and their functionalization of polymeric nanoplatforms for drug delivery

Cell penetrating peptides (CPPs), known as protein translocation domains, have emerged as efficient molecular transporters to overcome biological barriers and deliver cell-impermeable cargoes into cells. The conjugation of CPPs to polymeric nanoplatforms enhances the drug delivery efficiency thus increasing their therapeutic efficacy. However, conventional CPPs are generally lack of cell specificity and could be easily degraded in vivo. These limitations lead to the development of new CPPs with superior properties. To address the issue of cell specificity, activatable CPPs have been designed to be activated at desired site through different stimuli. On the other hand, macrocyclization has been used to constrain linear CPPs into their cyclic forms. This chemical optimization of peptides endows CPPs with enhanced stability and cell permeability. This brief review will cover recent advances in terms of different types of CPPs for enhanced cell penetration. In addition, the modification chemistry used to functionalize polymeric nanoplatforms with CPPs and their recent applications for drug delivery will also be discussed. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

A novel progress of drug delivery system for organelle targeting in tumour cells

At present, malignant tumours have become one of the most serious diseases that endanger human health. According to a survey on causes of death in Chinese population in early 1990s, the malignant tumours were the second leading cause of death. In the treatment of tumours, the ideal situation is that drugs should target and accumulate at tumour sites and destroy tumour cells specifically, without affecting normal cells and stem cells with regenerative capacity. This requires drugs to be specifically transported to the target organs, tissues, cells, and even specific organelles, like mitochondria, nuclei, lysosomes, endoplasmic reticulum (ER), and Golgi apparatus (GA). The nano drug delivery system can not only protect drugs from degradation but also facilitate functional modification and targeted drug delivery to the tumour site. This article mainly reviews the targeting of nano drug delivery systems to tumour cytoplasmic matrix, nucleus, mitochondria, ER, and lysosomes. Organelle-specific drug delivery system will be a major mean of targeting drug delivery with lower toxicity, less dosage and higher drug concentration in tumour cells.