Engineering of a Core-Shell Nanoplatform to Overcome Multidrug Resistance via ATP Deprivation

Emerging glucose oxidase-delivering nanomedicines for enhanced tumor therapy

Abnormalities in glucose metabolism have been shown to characterize malignant tumors. Glucose depletion by glucose oxidase (GOD) has shown great potential in tumor therapy by causing tumor starvation. Since 2017, nanomedicines have been designed and utilized to deliver GOD for more precise and effective glucose modulation, which can overcome intrinsic limitations of different cancer therapeutic modalities by remodeling the tumor microenvironment to enhance antitumor therapy. To date, the topic of GOD-delivering nanomedicines for enhancing tumor therapy has not been comprehensively summarized. Herein, this review aims to provide an overview and discuss in detail recent advances in GOD delivery and directly involved starvation therapy strategies, GOD-sensitized various tumor therapy strategies, and GOD-mediated multimodal antitumor strategies. Finally, the challenges and outlooks for the future progress of the emerging tumor therapeutic nanomedicines are discussed. This review provides intuitive and specific insights to a broad audience in the fields of nanomedicines, biomaterials, and cancer therapy.

Recent advances in polydopamine-coated metal-organic frameworks for cancer therapy

The creation and development of classical multifunctional nanomaterials are crucial for the advancement of nanotherapeutic treatments for tumors. Currently, metal-organic frameworks (MOFs) modified with polydopamine (PDA) are at the forefront of nanomedicine research, particularly in tumor diagnostics and therapy, owing to their exceptional biocompatibility, expansive specific surface area, multifaceted functionalities, and superior photothermal properties, which led to significant advancements in anti-tumor research. Consequently, a range of anti-cancer strategies has been devised by leveraging the exceptional capabilities of MOFs, including intelligent drug delivery systems, photodynamic therapy, and photothermal therapy, which are particularly tailored for the tumor microenvironment. In order to gain deeper insight into the role of MOFs@PDA in cancer diagnosis and treatment, it is essential to conduct a comprehensive review of existing research outcomes and promptly analyze the challenges associated with their biological applications. This will provide valuable perspectives on the potential of MOFs@PDA in clinical settings.

Recent advances in zeolitic imidazolate frameworks as drug delivery systems for cancer therapy

Biological nanotechnologies based on functional nanoplatforms have synergistically catalyzed the emergence of cancer therapies. As a subtype of metal-organic frameworks (MOFs), zeolitic imidazolate frameworks (ZIFs) have exploded in popularity in the field of biomaterials as excellent protective materials with the advantages of conformational flexibility, thermal and chemical stability, and functional controllability. With these superior properties, the applications of ZIF-based materials in combination with various therapies for cancer treatment have grown rapidly in recent years, showing remarkable achievements and great potential. This review elucidates the recent advancements in the use of ZIFs as drug delivery agents for cancer therapy. The structures, synthesis methods, properties, and various modifiers of ZIFs used in oncotherapy are presented. Recent advances in the application of ZIF-based nanoparticles as single or combination tumor treatments are reviewed. Furthermore, the future prospects, potential limitations, and challenges of the application of ZIF-based nanomaterials in cancer treatment are discussed. We except to fully explore the potential of ZIF-based materials to present a clear outline for their application as an effective cancer treatment to help them achieve early clinical application.

Polydopamine-Modified Polycaprolactone Scaffolds Loading Metal Nanoparticles for Bone Tissue Engineering

Recent advancements in materials synthesis and processing technology, coupled with a deeper understanding of bone nanoscale structure and biology, have provided new avenues for designing bioactive materials in bone tissue regenerative medicine. This Review focuses on the design and application of polydopamine-modified polycaprolactone scaffolds loading metal nanoparticles for bone tissue engineering. We explore their antibacterial properties and their ability to guide cell behavior. Specifically, we discuss the synthesis techniques, protein deposition, morphology variations, and interactions with the extracellular matrix of these scaffolds and biocompatibility and efficacy in promoting bone tissue regeneration in vitro and in vivo. Challenges and unmet needs are reviewed in the development of polymer- and metal-based materials for bone tissue engineering.

Metal-Coordinated Polydopamine Structures for Tumor Imaging and Therapy

Meticulously engineered nanomaterials achieve significant advances in the diagnosis and therapy of solid tumors by improving tumor delivery efficiency; and thereby, enhancing imaging and therapeutic efficacy. Currently, polydopamine (PDA) attracts widespread attention because of its biocompatibility, simplicity of preparation, abundant surface groups, and high photothermal conversion efficiency, which can be applied in drug delivery, photothermal therapy, theranostics, and other nanomedicine fields. Inspired by PDA structures that are rich in catechol and amino functional groups that can coordinate with various metal ions, which have charming qualities and characteristics, metal-coordinated PDA structures are exploited for tumor theranostics, but are not thoroughly summarized. Herein, this review summarizes the recent progress in the fabrication of metal-coordinated PDA structures and their availabilities in tumor imaging and therapy, with further in-depth discussion of the challenges and future perspectives of metal-coordinated PDA structures, with the aim that this systematic review can promote interdisciplinary intersections and provide inspiration for the further growth and clinical translation of PDA materials.

A triple-mode strategy combining low-temperature photothermal, photodynamic, and chemodynamic therapies for treating infectious skin wounds

The skin is the first natural barrier of the human body. Bacterial infections severely hinder the healing process of skin wounds and pose a great threat to human health. Therefore, it is particularly urgent to develop new antimicrobial strategies for bacterial pathogen clearance and wound healing. In this study, a metal-organic framework (MOF), Fe-MIL88B-NH2, was incorporated with the photosensitizer indocyanine green (ICG) to construct composite nanoparticles (MOF@ICG NPs) with multiple antibacterial activities. Under mild near-infrared (NIR) irradiation, the photosensitizer ICG in the MOF@ICG NPs undergoes photothermal conversion (∼45 °C) and photodynamic reactions to generate heat and singlet oxygen (1O2). In addition, the Fenton reaction of the NPs with hydrogen peroxide (H2O2) in the bacterial infection microenvironment resulted in the generation of hydroxyl radicals (˙OH), thus achieving the three-mode combination of low-temperature photothermal therapy (PTT)/photodynamic therapy (PDT)/chemodynamic therapy (CDT). The in vitro experimental results showed that MOF@ICG MPs had excellent antibacterial properties and good cytocompatibility, with some ability to promote the migration of L-929 fibroblasts. Furthermore, under NIR irradiation, MOF@ICG NPs could significantly kill bacteria and promote skin wound healing according to the results of animal experiments. The wound healing rate reached 87.1% after 7 days of treatment. The research results break through the limitations of single-mode antibacterial technology and provide certain theoretical guidance and technical support for the research and development of new antibacterial materials.

Temperature Self-Limited Intelligent Thermo-chemotherapeutic Lipid Nanosystem for P-gp Reversal Time Window Matched Pulse Treatment of MDR Tumor

Mild photothermal therapy (PTT) shows the potential for chemosensitization by tumor-localized P-glycoprotein (P-gp) modulation. However, conventional mild PTT struggles with real-time uniform temperature control, obscuring the temperature-performance relationship and resulting in thermal damage. Besides, the time-performance relationship and the underlying mechanism of mild PTT-mediated P-gp reversal remains elusive. Herein, we developed a temperature self-limiting lipid nanosystem (RFE@PD) that integrated a reversible organic heat generator (metal-phenolic complexes) and metal chelator (deferiprone, DFP) encapsulated phase change material. Upon NIR irradiation, RFE@PD released DFP for blocking ligand-metal charge transfer to self-limit temperature below 45 °C, and rapidly reduced P-gp within 3 h via Ubiquitin-proteasome degradation. Consequently, the DOX·HCl-loaded thermo-chemotherapeutic lipid nanosystem (RFE@PD-DOX) led to dramatically improved drug accumulation and 5-fold chemosensitization in MCF-7/ADR tumor models by synchronizing P-gp reversal and drug pulse liberation, achieving a tumor inhibition ratio of 82.42%. This lipid nanosystem integrated with "intrinsic temperature-control" and "temperature-responsive pulse release" casts new light on MDR tumor therapy.

Activation of the PPARγ/NF-κB pathway by A-MPDA@Fe3O4@PVP via scavenging reactive oxygen species to alleviate hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (IRI) is a common pathological process during hepatectomy and liver transplantation and the two primary reasons for hepatic IRI are reactive oxygen species (ROS)-mediated oxidative stress and excessive inflammatory responses. Herein, a novel antioxidant nanodrug (A-MPDA@Fe3O4@PVP) is prepared by employing L-arginine-doped mesoporous polydopamine (A-MPDA) nanoparticles as the carrier for deposition of ultra-small ferric oxide (Fe3O4) nanoparticles and further surface modification with polyvinylpyrrolidone (PVP). A-MPDA@Fe3O4@PVP not only effectively reduces the aggregation of ultra-small Fe3O4, but also simultaneously replicates the catalytic activity of catalase (CAT) and superoxide dismutase (SOD). A-MPDA@Fe3O4@PVP with good antioxidant activity can rapidly remove various toxic reactive oxygen species (ROS) and effectively regulate macrophage polarization in vitro. In the treatment of hepatic IRI, A-MPDA@Fe3O4@PVP effectively alleviates ROS-induced oxidative stress, reduces the expression of inflammatory factors, and prevents apoptosis of hepatocytes through immune regulation. A-MPDA@Fe3O4@PVP can further protect liver tissue by activating the PPARγ/NF-κB pathway. This multiplex antioxidant enzyme therapy can provide new references for the treatment of IRI in organ transplantation and other ROS-related injuries such as fibrosis, cirrhosis, and bacterial and hepatic viral infection.

Polyphenol-Based Nanosystems for Next-Generation Cancer Therapy: Multifunctionality, Design, and Challenges

With the continuous updating of cancer treatment methods and the rapid development of precision medicine in recent years, there are higher demands for advanced and versatile drug delivery systems. Scientists are committed to create greener and more effective nanomedicines where the carrier is no longer limited to a single function of drug delivery. Polyphenols, which can act as both active ingredients and fundamental building blocks, are being explored as potential multifunctional carriers that are efficient and safe for design purposes. Due to their intrinsic anticancer activity, phenolic compounds have shown surprising expressiveness in ablation of tumor cells, overcoming cancer multidrug resistance (MDR), and enhancing immunotherapeutic efficacy. This review provides an overview of recent advances in the design, synthesis, and application of versatile polyphenol-based nanosystems for cancer therapy in various modes. Moreover, the merits of polyphenols and the challenges for their clinical translation are also discussed, and it is pointed out that the novel polyphenol delivery system requires further optimization and validation.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

Ablation of Gap Junction Protein Improves the Efficiency of Nanozyme-Mediated Catalytic/Starvation/Mild-Temperature Photothermal Therapy

Reactive oxygen species (ROS)-mediated tumor catalytic therapy is typically hindered by gap junction proteins that form cell-to-cell channels to remove cytotoxic ROS, thereby protecting tumor cells from oxidative damage. In this work, a multifunctional nanozyme, FePGOGA, is designed and prepared by Fe(III)-mediated oxidative polymerization (FeP), followed by glucose oxidase (GOx) and GAP19 peptides co-loading through electrostatic and π-π interactions. The FePGOGA nanozyme exhibits excellent cascade peroxidase- and glutathione-oxidase-like activities that efficiently catalyze hydrogen peroxide conversion to hydroxyl radicals and convert reduced glutathione to oxidized glutathione disulfide. The loaded GOx starves the tumors and aggravates tumor oxidative stress through glucose decomposition, while GAP19 peptides block the hemichannels by inducing degradation of Cx43, thus increasing the accumulation of intracellular ROS, and decreasing the transport of intracellular glucose. Furthermore, the ROS reacts with primary amines of heat shock proteins to destroy their structure and function, enabling tumor photothermal therapy at the widely sought-after mild temperature (mildPTT, ≤45 °C). In vivo experiments demonstrate the significant antitumor effectof FePGOGA on cal27 xenograft tumors under near-infrared light irradiation. This study demonstrates the successful ablation of gap junction proteins to overcome resistance to ROS-mediated therapy, providing a regulator to suppress tumor self-preservation during tumor starvation, catalytic therapy, and mildPTT.

Multisubcellular organelle-targeting nanoparticle for synergistic chemotherapy and photodynamic/photothermal tumor therapy

Background: The subcellular organelle-targeting strategy has attracted wide attention for a variety of reasons, including strong specificity, high accuracy, low dose administration and few side effects. It is an important and challenging task to explore the multisubcellular organelle-targeting strategy to achieve effective tumor treatment. Materials & methods: Using bovine serum albumin as a nanoreactor, BSA/Cu/NQ/IR780/DOX nanoparticles (NPs) were constructed via drug-induced protein self-assembly. Folic acid was then coupled to the surface of NPs to prepare folate receptor-targeted FA-BSA/Cu/NQ/IR780/DOX NPs. Results & conclusion: The FA-BSA/Cu/NQ/IR780/DOX NPs exhibit multifunctional properties, including multisubcellular organelle-targeting, induction of response release in the tumor microenvironment, fluorescence imaging capabilities and potential for synergistic chemotherapy and photodynamic/photothermal tumor therapy.

Oxygen Self-Generating Nanoreactor Mediated Ferroptosis Activation and Immunotherapy in Triple-Negative Breast Cancer

The hypoxia microenvironment of solid tumors poses a technological bottleneck for ferroptosis and immunotherapy in clinical oncology. Nanoreactors based on special physiological signals in tumor cells are able to avoid various tumor tolerance mechanisms by alleviating the intracellular hypoxia environment. Herein we reported a nanoreactor Cu_2-xSe that enabled the conversion of Cu elements between Cu⁺ and Cu²⁺ for the generation of O₂ and the consumption of intracellular GSH content. Furthermore, to enhance the catalytic and ferroptosis-inducing activities of the nanoreactors, the ferroptosis agonist Erastin was loaded on the ZIF-8 coating on the surface of Cu_2-xSe to up-regulate the expression of NOX4 protein, increase the intracellular H₂O₂ content, catalyze the Cu⁺ to produce O₂ and activate ferroptosis. In addition, the nanoreactors were simultaneously surface functionalized with PEG polymer and folic acid molecules, which ensured the in vivo blood circulation and tumor-specific uptake. In vitro and in vivo experiments demonstrated that the functionalized self-supplying nanoreactors can amplify the ability to generate O₂ and consume intracellular GSH via the interconversion of Cu elements Cu⁺ and Cu²⁺, and impair the GPX4/GSH pathway and HIF-1α protein expression. At the same time, by alleviating the intracellular hypoxia environment, the expression of miR301, a gene in the secreted exosomes was decreased, which ultimately affected the phenotype polarization of TAMs and increased the content of IFN γ secreted by CD8⁺ T cells, which further promoted the ferroptosis induced by Erastin-loaded nanoreactors. This combined therapeutic strategy of activating the tumor immune response and ferroptosis via self-supplying nanoreactors provides a potential strategy for clinical application.

Progress in the studies on the molecular mechanisms associated with multidrug resistance in cancers

Chemotherapy is one of the important methods to treat cancer, and the emergence of multidrug resistance (MDR) is one major cause for the failure of cancer chemotherapy. Almost all anti-tumor drugs develop drug resistance over a period of time of application in cancer patients, reducing their effects on killing cancer cells. Chemoresistance can lead to a rapid recurrence of cancers and ultimately patient death. MDR may be induced by multiple mechanisms, which are associated with a complex process of multiple genes, factors, pathways, and multiple steps, and today the MDR-associated mechanisms are largely unknown. In this paper, from the aspects of protein-protein interactions, alternative splicing (AS) in pre-mRNA, non-coding RNA (ncRNA) mediation, genome mutations, variance in cell functions, and influence from the tumor microenvironment, we summarize the molecular mechanisms associated with MDR in cancers. In the end, prospects for the exploration of antitumor drugs that can reverse MDR are briefly discussed from the angle of drug systems with improved targeting properties, biocompatibility, availability, and other advantages.

Enzyme-loaded glycogen nanoparticles with tumor-targeting Activatable host-guest supramolecule for augmented chemodynamic therapy

Chemodynamic therapy (CDT) has advantages in site-specific killing tumor and avoiding systemically side effect. Although numerous nano-systems have been developed to enhance the intracellular hydrogen peroxide (H₂O₂) for improving CDT effect, the biocompatibility of the materials limits their further biomedical applications. Herein glycogen, as a natural biological macromolecule, was used to construct a new targeted separable GOx@GF/HC nanoparticle system to deliver glucose oxidase (GOx) for CDT/starvation tumor therapy. Amination glycogen-ferrocene (GF) as a guest core and hyaluronic acid-β-cyclodextrin (HC) as a host shell were synthesized and self-assembled through host-guest interactions to deliver GOx. After being entered into tumor cells, GOx were released to catalyze glucose to produce gluconic acid and H₂O₂, which in turn cut off the nutrition of tumor cells for starvation therapy and enhanced the generation of OH with ferrous ion through Fenton reaction. Furthermore, GOx@GF/HC also exhibited remarkable tumor-targeting and tumor-suppression in vivo. Therefore, the GOx@GF/HC system can exert excellent synergistic effect of CDT and starvation therapy on cancer treatment through a cascade reaction, which have some potential application for the development of CDT tumor-treatment.

Multienzyme-like Reactivity Cooperatively Impairs Glutathione Peroxidase 4 and Ferroptosis Suppressor Protein 1 Pathways in Triple-Negative Breast Cancer for Sensitized Ferroptosis Therapy

Ferroptosis is a recently discovered route of regulated cell death that offers the opportunities for the treatment of chemotherapy-resistant tumor indications, but its efficacy can be affected by the glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) antioxidant mechanisms, posing significant challenges for its clinical translation. In this study, we report a Cu-tetra(4-carboxyphenyl)porphyrin chloride(Fe(III)) (Cu-TCPP(Fe)) metal organic framework (MOF)-based nanosystem for the efficient incorporation of Au nanoparticles (NPs) and RSL3, which can demonstrate enzyme-like activities to universally suppress the antiferroptotic pathways in tumor cells for amplifying ferroptotic damage. Herein, Cu-TCPP(Fe) MOF nanosheets were integrated with Au NPs via in situ nucleation and loaded with RSL3 via π-π stacking, which were eventually modified with polyethylene glycol (PEG) and iRGD for tumor-targeted drug delivery. Specifically, the Au NPs can demonstrate glucose oxidase-like activities for efficient glucose depletion, thus disrupting the pentose phosphate pathway to impede reduced glutathione (GSH) biosynthesis and prevent the recycling of coenzyme Q10 (CoQ10) to CoQ10H2, while Cu species can oxidize GSH into oxidized glutathione (GSSG). These nanocatalytic activities can lead to the simultaneous inhibition of the GPX4/GSH and FSP1/CoQ10H2 pathways and cooperate with the GPX4-deactivating function of RSL3 to cause pronounced ferroptotic damage, thereby providing a strong rationale for the application of ferroptosis therapy in the clinic.

Bioenzyme-based nanomedicines for enhanced cancer therapy

Bioenzymes that catalyze reactions within living systems show a great promise for cancer therapy, particularly when they are integrated with nanoparticles to improve their accumulation into tumor sites. Nanomedicines can deliver toxic bioenzymes into cancer cells to directly cause their death for cancer treatment. By modulating the tumor microenvironment, such as pH, glucose concentration, hypoxia, redox levels and heat shock protein expression, bioenzyme-based nanomedicines play crucial roles in improving the therapeutic efficacy of treatments. Moreover, bioenzyme-mediated degradation of the major components in tumor extracellular matrix greatly increases the penetration and retention of nanoparticles in deep tumors and infiltration of immune cells into tumor tissues, thus enhancing the efficacies of chemotherapy, phototherapy and immunotherapy. In this review, we summarize the recent progresses of bioenzyme-based nanomedicines for enhanced cancer therapy. The design and working mechanisms of the bioenzyme-based nanomedicines to achieve enhanced chemotherapy, photothermal therapy, photodynamic therapy, chemodynamic therapy, radiotherapy and immunotherapy are introduced in detail. At the end of this review, a conclusion and current challenges and perspectives in this field are given.

Recent developments in mesoporous polydopamine-derived nanoplatforms for cancer theranostics

Polydopamine (PDA), which is derived from marine mussels, has excellent potential in early diagnosis of diseases and targeted drug delivery owing to its good biocompatibility, biodegradability, and photothermal conversion. However, when used as a solid nanoparticle, the application of traditional PDA is restricted because of the low drug-loading and encapsulation efficiencies of hydrophobic drugs. Nevertheless, the emergence of mesoporous materials broaden our horizon. Mesoporous polydopamine (MPDA) has the characteristics of a porous structure, simple preparation process, low cost, high specific surface area, high light-to-heat conversion efficiency, and excellent biocompatibility, and therefore has gained considerable interest. This review provides an overview of the preparation methods and the latest applications of MPDA-based nanodrug delivery systems (chemotherapy combined with radiotherapy, photothermal therapy combined with chemotherapy, photothermal therapy combined with immunotherapy, photothermal therapy combined with photodynamic/chemodynamic therapy, and cancer theranostics). This review is expected to shed light on the multi-strategy antitumor therapy applications of MPDA-based nanodrug delivery systems.

Fabrication of a pH-responsive core-shell nanosystem with a low-temperature photothermal therapy effect for treating bacterial biofilm infection

Recently, photothermal therapy (PTT) has been recognized as a viable alternative strategy against bacterial biofilm infection. However, the hyperthermia required for PTT to ablate a biofilm usually induces damage in normal tissues/organs nearby. Herein, we developed zeolite-based imidazole framework (ZIF-8)-coated mesoporous polydopamine (MPDA) core-shell nanoparticles and then loaded Pifithrin-μ (PES), a natural inhibitor of heat-shock protein (HSP) that plays an essential role in bacteria resisting heating-induced damage. The ZIF-8 shell of the MPDA@ZIF-8/PES nanoplatform enabled a rapid degradation in response to the acidic environment in bacterial biofilm infection, which triggered the controlled release of PES and Zn ions. As a result, HSP was remarkably suppressed for enhancing PTT efficacy upon mild near-infrared light irradiation. In addition, the release of Zn²⁺ also had an antibacterial/antibiofilm effect. Thus, the fabricated nanosystem was able to induce the effective elimination of the bacterial biofilm, realizing low-temperature PTT (∼45 °C) with excellent antibacterial efficacy. This work presented here not only provides a facile approach to fabricate the MPDA@ZIF-8/PES nanosystem with the responsiveness of the bacterial infection environment, but also proposes a promising low-temperature PTT strategy to treat bacterial biofilm-infection effectively.

pH-Sensitive Polymeric Vesicles for GOx/BSO Delivery and Synergetic Starvation-Ferroptosis Therapy of Tumor

Typical glucose oxidase (GOx)-based starvation therapy is a promising strategy for tumor treatment; however, it is still difficult to achieve an effective therapeutic effect via a single starvation therapy. Herein, we designed a pH-sensitive polymeric vesicle (PV) self-assembled by histamine-modified chondroitin sulfate (CS-his) for codelivery of GOx and l-buthionine sulfoximine (BSO). GOx can consume glucose to induce the starvation therapy after the PVs reach cancer cell. Moreover, the product H₂O₂ will be reduced by a high concentration of glutathione (GSH) in the tumor cell, resulting in a reduction of the GSH content. The released BSO finally further reduced the GSH level. As a result, the signaling pathway of the ferroptosis will be activated. The in vivo results demonstrated that GOx/BSO@CS PVs exhibit a good inhibitory effect on the growth of 4T1 tumors in mice. Thus, this work provides a facile strategy to prepare pH-sensitive nanomedicine for synergistic starvation-ferroptosis therapy of tumor.

Nanoplatform-based natural products co-delivery system to surmount cancer multidrug-resistant

The emergence of multidrug resistance (MDR) in malignant tumors is the primary reason for invalid chemotherapy. Antitumor drugs are often adversely affected by the MDR of tumor cells. Treatments using conventional drugs, which have specific drug targets, hardly regulate the complex signaling pathway of MDR cells because of the complex formation mechanism of MDR. However, natural products have positive advantages, such as high efficiency, low toxicity, and ability to target multiple mechanism pathways associated with MDR. Natural products, as MDR reversal agents, synergize with chemotherapeutics and enhance the sensitivity of tumor cells to chemotherapeutics, and the co-delivery of natural products and antitumor drugs with nanocarriers maximizes the synergistic effects against MDR in tumor cells. This review summarizes the molecular mechanisms of MDR, the advantages of natural products combined with chemotherapeutics in offsetting complicated MDR mechanisms, and the types and mechanisms of natural products that are potential MDR reversal modulators. Meanwhile, aiming at the low bioavailability of cocktail combined natural products and chemotherapeutic in vivo, the advantages of nanoplatform-based co-delivery system and recent research developments are illustrated on the basis of our previous research. Finally, prospective horizons are analyzed, which are expected to considerably improve the nano-co-delivery of natural products and chemotherapeutic systems for MDR reversal in cancer.

Cancer stem cells, epithelial-mesenchymal transition, ATP and their roles in drug resistance in cancer

The cancer stem cell (CSC) state and epithelial-mesenchymal transition (EMT) activation are tightly interconnected. Cancer cells that acquire the EMT/CSC phenotype are equipped with adaptive metabolic changes to maintain low reactive oxygen species levels and stemness, enhanced drug transporters, anti-apoptotic machinery and DNA repair system. Factors present in the tumor microenvironment such as hypoxia and the communication with non-cancer stromal cells also promote cancer cells to enter the EMT/CSC state and display related resistance. ATP, particularly the high levels of intratumoral extracellular ATP functioning through both signaling pathways and ATP internalization, induces and regulates EMT and CSC. The three of them work together to enhance drug resistance. New findings in each of these factors will help us explore deeper into mechanisms of drug resistance and suggest new resistance-associated markers and therapeutic targets.

Intervention of Polydopamine Assembly and Adhesion on Nanoscale Interfaces: State-of-the-Art Designs and Biomedical Applications

The translation of mussel-inspired wet adhesion to biomedical engineering fields have catalyzed the emergence of polydopamine (PDA)-based nanomaterials with privileged features and properties of conducting multiple interfacial interactions. Recent concerns and progress on the understanding of PDA's hierarchical structure and progressive assembly are inspiring approaches toward novel nanostructures with property and function advantages over simple nanoparticle architectures. Major breakthroughs in this field demonstrated the essential role of π-π stacking and π-cation interactions in the rational intervention of PDA self-assembly. In this review, the recently emerging concepts in the preparation and application of PDA nanomaterials, including 3D mesostructures, low-dimensional nanostructures, micelle/nanoemulsion based nanoclusters, as well as other multicomponent nanohybrids by the segregation and organization of PDA building blocks on nanoscale interfaces are outlined. The contribution of π-electron interactions on the interfacial loading/release of π electron-rich molecules (nucleic acids, drugs, photosensitizers) and the exogenous coupling of optical energy, as well as the impact of wet-adhesion interactions on the nano-bio interface interplay, are highlighted by discussing the structure-property relationships in their featured applications including fluorescent biosensing, gene therapy, drug delivery, phototherapy, combined therapy, etc. The limitations of current explorations, and future research directions are also discussed.

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

NIR-Controlled Treatment of Multidrug-Resistant Tumor Cells by Mesoporous Silica Capsules Containing Gold Nanorods and Doxorubicin

Multidrug resistance (MDR) is identified as a major impediment to the efficient chemotherapy of cancer, and considerable endeavors have been devoted to reverse MDR containing structuring varieties of multifunctional nanocarriers. Here, a specially light-activated hollow mesoporous silica nanocontainer with an in situ-synthesized Au nanorod (AuNR) core and a surface-modified hairpin structure DNA gatekeeper is reported for treating MDR tumor cells. In this system, the AuNR only fills part of the space in hollow mesoporous silica due to its controllable size, and the remaining space is used to load enough DOX. By controlling the near-infrared (NIR) laser intensity and exposure duration, the configuration of hairpin-structured DNA (T_m = 51.4 °C) can change reversibly and then trigger the controllable intracellular release of DOX, leading to a significantly enhanced chemotherapeutic efficacy and adjustable photothermal treatment for multidrug-resistant cancer cells. The in vitro experiments showed that this system could effectively overcome the MDR of HepG2-adm cells (a MDR cell line of human hepatocarcinoma cells) by the increased concentration of DOX intracellularly and the photothermal conversion of AuNRs, even at a low concentration (e.g., 30 μg mL^-1). Therefore, this NIR-triggered chemo-photothermal synergistic treatment system can be used as a promising efficient strategy in reversing the multidrug resistance for cancer therapy.