Sequential Delivery of Cyclopeptide RA-V and Doxorubicin for Combination Therapy on Resistant Tumor and In Situ Monitoring of Cytochrome c Release

Rhynchophylline as an agonist of sirtuin 3 ameliorates endothelial dysfunction via antagonizing mitochondrial damage of endothelial progenitor cells

BACKGROUND AND PURPOSE

Mitochondrial dysregulation of endothelial progenitor cells (EPCs) has been implicated in endothelial destruction and hypertension. Regulation of silent information regulator 3 (sirtuin 3; SIRT3) in mitochondrial damage of EPCs and the underlying molecular mechanisms remain unclear, and evidence of selective SIRT3 agonists for the treatment of hypertension also is lacking.

EXPERIMENTAL APPROACH

Here, we discovered a potent SIRT3 agonist, rhynchophylline (Rhy), and explored its underlying action on mitochondrial damage of EPCs and endothelial dysfunction.

KEY RESULTS

In spontaneously hypertensive rats, Rhy reduced blood pressure and ameliorated vasomotion, paralleling improved EPC function in the peripheral circulation. Moreover, Rhy alleviated mitochondrial damage and inhibited apoptosis via the mitochondrial apoptotic pathway. SIRT3 knockdown interrupted the regulation of mitochondrial homeostasis induced by Rhy, thus abolishing its antagonizing effect on EPC dysfunction and endothelial damage, suggesting that Rhy protection of EPC mitochondria is mediated via the activation of SIRT3. Rhy restrained the production of mitochondrial ROS and improved the activity of superoxide dismutase 2 (SOD2) in a SIRT3-dependent manner, whereas silencing SOD2 eliminated the inhibition by Rhy of oxidative stress and apoptosis, reflecting that SOD2 was indispensable for the regulation of Rhy on mitochondrial dysfunction and the mitochondrial-mediated apoptosis pathway.

CONCLUSION AND IMPLICATIONS

SIRT3-dependent mitochondrial homeostasis contributes to attenuating hypertension-related EPC dysfunction and endothelial injury, and Rhy itself is a potent and targeted SIRT3 agonist that prevented mitochondrial dysfunction by regulating the SIRT3/SOD2 pathway, which may provide new clues for drug candidates for hypertension therapeutics.

Multi-drug sequential release systems: Construction and application for synergistic tumor treatment

In tumor treatment, the sequence and timing of drug action have a large influence on therapeutic efficacy. Multi-drug sequential release systems (MDSRS) enable the sequential and/or on-demand release of multiple drugs following the single administration of a therapeutic agent. Several researchers have explored MDSRS, providing fresh strategies for synergistic cancer therapy. This review article first introduces the main characteristics of MDSRS. It then elaborates on the design principles of MDSRS. Subsequently, it summarizes the various structures of carriers used for constructing MDSRS, including core-shell structure, Layer-by-layer structure, Janus structure and hydrogel. Next, through specific examples, the article emphasizes the application of MDSRS in cancer treatment, focusing on their role in remodeling the tumor microenvironment (TME) and enhancing therapeutic effects through multiple mechanisms. Finally, the article discusses the current limitations and challenges of these systems and proposes potential future solutions. Overall, this review underscores the importance of the sequence and timing of drug therapy in cancer treatment, providing valuable theoretical and technical guidance for pharmaceutical research.

Subcellular Drug Distribution: Exploring Organelle-Specific Characteristics for Enhanced Therapeutic Efficacy

The efficacy and potential toxicity of drug treatments depends on the drug concentration at its site of action, intricately linked to its distribution within diverse organelles of mammalian cells. These organelles, including the nucleus, endosome, lysosome, mitochondria, endoplasmic reticulum, Golgi apparatus, lipid droplets, exosomes, and membrane-less structures, create distinct sub-compartments within the cell, each with unique biological features. Certain structures within these sub-compartments possess the ability to selectively accumulate or exclude drugs based on their physicochemical attributes, directly impacting drug efficacy. Under pathological conditions, such as cancer, many cells undergo dynamic alterations in subcellular organelles, leading to changes in the active concentration of drugs. A mechanistic and quantitative understanding of how organelle characteristics and abundance alter drug partition coefficients is crucial. This review explores biological factors and physicochemical properties influencing subcellular drug distribution, alongside strategies for modulation to enhance efficacy. Additionally, we discuss physiologically based computational models for subcellular drug distribution, providing a quantifiable means to simulate and predict drug distribution at the subcellular level, with the potential to optimize drug development strategies.

Self-assembly of enzymes and prodrugs with clickable amino acids for nucleus-targeted cancer therapy

A nucleus-targeted nanocomposite was prepared by clickable amino acid-tuned one-step co-assembly of proteins and chemotherapeutics. The nanocomposite with favorable pharmacokinetic behavior can effectively accumulate in the nucleus, thereby significantly enhancing the anticancer therapeutic effect both in vitro and in vivo.

The Application of Nano-drug Delivery System With Sequential Drug Release Strategies in Cancer Therapy

Currently, multidrug combinations are often used clinically to improve the efficacy of oncology chemotherapy, but multidrug combinations often lead to multidrug resistance and decreased performance, resulting in more severe side effects than monotherapy. Therefore, sequential drug release strategies in time and space as well as nano-carriers that respond to the tumor microenvironment have been developed. First, the advantage of the sequential release strategy is that they can load multiple drugs simultaneously to meet their spatiotemporal requirements and stability, thus exerting synergistic effects of two or more drugs. Second, in some cases, sequential drug delivery of different molecular targets can improve the sensitivity of cancer cells to drugs. Control the metabolism of cancer cells, and remodel tumor vasculature. Finally, some drug combinations with built-in release control are used for sequential administration. This paper focuses on the use of nanotechnology and built-in control device to construct drug delivery carriers with different stimulation responses, thus achieving the sequential release of drugs. Therefore, the nano-sequential delivery carrier provides a new idea and platform for the therapeutic effect of various drugs and the synergistic effect among drugs.

Tumor Abnormality-Oriented Nanomedicine Design

Anticancer nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs. However, challenges remain in augmenting their therapeutic efficacy. Nanomedicines responsive to the pathological abnormalities in the tumor microenvironment (TME) are expected to overcome the biological limitations of conventional nanomedicines, enhance the therapeutic efficacies, and further reduce the side effects. This Review aims to quantitate the various pathological abnormalities in the TME, which may serve as unique endogenous stimuli for the design of stimuli-responsive nanomedicines, and to provide a broad and objective perspective on the current understanding of stimuli-responsive nanomedicines for cancer treatment. We dissect the typical transport process and barriers of cancer drug delivery, highlight the key design principles of stimuli-responsive nanomedicines designed to tackle the series of barriers in the typical drug delivery process, and discuss the "all-into-one" and "one-for-all" strategies for integrating the needed properties for nanomedicines. Ultimately, we provide insight into the challenges and future perspectives toward the clinical translation of stimuli-responsive nanomedicines.

Functional Materials for Subcellular Targeting Strategies in Cancer Therapy: Progress and Prospects

Neoadjuvant and adjuvant therapies have made significant progress in cancer treatment. However, tumor adjuvant therapy still faces challenges due to the intrinsic heterogeneity of cancer, genomic instability, and the formation of an immunosuppressive tumor microenvironment. Functional materials possess unique biological properties such as long circulation times, tumor-specific targeting, and immunomodulation. The combination of functional materials with natural substances and nanotechnology has led to the development of smart biomaterials with multiple functions, high biocompatibilities, and negligible immunogenicities, which can be used for precise cancer treatment. Recently, subcellular structure-targeting functional materials have received particular attention in various biomedical applications including the diagnosis, sensing, and imaging of tumors and drug delivery. Subcellular organelle-targeting materials can precisely accumulate therapeutic agents in organelles, considerably reduce the threshold dosages of therapeutic agents, and minimize drug-related side effects. This review provides a systematic and comprehensive overview of the research progress in subcellular organelle-targeted cancer therapy based on functional nanomaterials. Moreover, it explains the challenges and prospects of subcellular organelle-targeting functional materials in precision oncology. The review will serve as an excellent cutting-edge guide for researchers in the field of subcellular organelle-targeted cancer therapy.

Nanomedicine in cancer therapy

Cancer remains a highly lethal disease in the world. Currently, either conventional cancer therapies or modern immunotherapies are non-tumor-targeted therapeutic approaches that cannot accurately distinguish malignant cells from healthy ones, giving rise to multiple undesired side effects. Recent advances in nanotechnology, accompanied by our growing understanding of cancer biology and nano-bio interactions, have led to the development of a series of nanocarriers, which aim to improve the therapeutic efficacy while reducing off-target toxicity of the encapsulated anticancer agents through tumor tissue-, cell-, or organelle-specific targeting. However, the vast majority of nanocarriers do not possess hierarchical targeting capability, and their therapeutic indices are often compromised by either poor tumor accumulation, inefficient cellular internalization, or inaccurate subcellular localization. This Review outlines current and prospective strategies in the design of tumor tissue-, cell-, and organelle-targeted cancer nanomedicines, and highlights the latest progress in hierarchical targeting technologies that can dynamically integrate these three different stages of static tumor targeting to maximize therapeutic outcomes. Finally, we briefly discuss the current challenges and future opportunities for the clinical translation of cancer nanomedicines.

Advances in Lipid-Based Codelivery Systems for Cancer and Inflammatory Diseases

Combination therapy targeting multiple therapeutic targets is a favorable strategy to achieve better therapeutic outcomes in cancer and inflammatory diseases. Codelivery is a subfield of drug delivery that aims to achieve combined delivery of diverse therapeutic cargoes within the same delivery system, thereby ensuring delivery to the same site and providing an opportunity to tailor the release kinetics as desired. Among the wide range of materials being investigated in the design of codelivery systems, lipids have stood out on account of their low toxicity, biocompatibility, and ease of formulation scale-up. This review highlights the advances of the last decade in lipid-based codelivery systems focusing on the codelivery of drug-drug, drug-nucleic acid, nucleic acid-nucleic acid, and protein therapeutic-based combinations for targeted therapy in cancer and inflammatory diseases.

Conquering Cancer Multi-Drug Resistance Using Curcumin and Cisplatin Prodrug-Encapsulated Mesoporous Silica Nanoparticles for Synergistic Chemo- and Photodynamic Therapies

Recently, the development of anti-cancer approaches using different physical or chemical pathways has shifted from monotherapy to synergistic therapy, which can enhance therapeutic effects. As a result, enormous efforts have been devoted to developing various delivery systems encapsulated with dual agents for synergistic effects and to combat cancer cells acquired drug resistance. In this study, we show how to make Institute of Bioengineering and Nanotechnology (IBN)-1-based mesoporous silica nanoparticles (MSNs) for multifunctional drug delivery to overcome drug resistance cancer therapy. Initially, curcumin (Cur)-embedded IBN-1 nanocomposites (IBN-1-Cur) are synthesized in a simple one-pot co-condensation and then immobilized with the prodrug of Cisplatin (CP) on the carboxylate-modified surface (IBN-1-Cur-CP) to achieve photodynamic therapy (PDT) and chemotherapy in one platform, respectively, in the fight against multidrug resistance (MDR) of MES-SA/DX5 cancer cells. The Pluronic F127 triblock copolymer, as the structure-directing agent, in nanoparticles acts as a p-glycoprotein (p-gp) inhibitor. These designed hybrid nanocomposites with excellent structural properties are efficiently internalized by the endocytosis and successfully deliver Cur and CP molecules into the cytosol. Furthermore, the presence of Cur photosensitizer in the nanochannels of MSNs resulted in increased levels of cellular reactive oxygen species (ROS) under light irradiation. Thus, IBN-1-Cur-CP showed excellent anti-cancer therapy in the face of MES-SA/DX5 resistance cancer cells, owing to the synergistic effects of chemo- and photodynamic treatment.

Nanocarriers for intracellular co-delivery of proteins and small-molecule drugs for cancer therapy

In the past few decades, the combination of proteins and small-molecule drugs has made tremendous progress in cancer treatment, but it is still not satisfactory. Because there are great differences in molecular weight, water solubility, stability, pharmacokinetics, biodistribution, and the ways of release and action between macromolecular proteins and small-molecule drugs. To improve the efficacy and safety of tumor treatment, people are committed to developing protein and drug co-delivery systems. Currently, intracellular co-delivery systems have been developed that integrate proteins and small-molecule drugs into one nanocarrier via various loading strategies. These systems significantly improve the blood stability, half-life, and biodistribution of proteins and small-molecule drugs, thus increasing their concentration in tumors. Furthermore, proteins and small-molecule drugs within these systems can be specifically targeted to tumor cells, and are released to perform functions after entering tumor cells simultaneously, resulting in improved effectiveness and safety of tumor treatment. This review summarizes the latest progress in protein and small-molecule drug intracellular co-delivery systems, with emphasis on the composition of nanocarriers, as well as on the loading methods of proteins and small-molecule drugs that play a role in cells into the systems, which have not been summarized by others so far.

Mitochondrial adaptation in cancer drug resistance: prevalence, mechanisms, and management

Drug resistance represents a major obstacle in cancer management, and the mechanisms underlying stress adaptation of cancer cells in response to therapy-induced hostile environment are largely unknown. As the central organelle for cellular energy supply, mitochondria can rapidly undergo dynamic changes and integrate cellular signaling pathways to provide bioenergetic and biosynthetic flexibility for cancer cells, which contributes to multiple aspects of tumor characteristics, including drug resistance. Therefore, targeting mitochondria for cancer therapy and overcoming drug resistance has attracted increasing attention for various types of cancer. Multiple mitochondrial adaptation processes, including mitochondrial dynamics, mitochondrial metabolism, and mitochondrial apoptotic regulatory machinery, have been demonstrated to be potential targets. However, recent increasing insights into mitochondria have revealed the complexity of mitochondrial structure and functions, the elusive functions of mitochondria in tumor biology, and the targeting inaccessibility of mitochondria, which have posed challenges for the clinical application of mitochondrial-based cancer therapeutic strategies. Therefore, discovery of both novel mitochondria-targeting agents and innovative mitochondria-targeting approaches is urgently required. Here, we review the most recent literature to summarize the molecular mechanisms underlying mitochondrial stress adaptation and their intricate connection with cancer drug resistance. In addition, an overview of the emerging strategies to target mitochondria for effectively overcoming chemoresistance is highlighted, with an emphasis on drug repositioning and mitochondrial drug delivery approaches, which may accelerate the application of mitochondria-targeting compounds for cancer therapy.

Stimulus-Responsive Sequential Release Systems for Drug and Gene Delivery

In recent years, a range of studies have been conducted with the aim to design and characterize delivery systems that are able to release multiple therapeutic agents in controlled and programmed temporal sequences, or with spatial resolution inside the body. This sequential release occurs in response to different stimuli, including changes in pH, redox potential, enzyme activity, temperature gradients, light irradiation, and by applying external magnetic and electrical fields. Sequential release (SR)-based delivery systems, are often based on a range of different micro- or nanocarriers and may offer a silver bullet in the battle against various diseases, such as cancer. Their distinctive characteristic is the ability to release one or more drugs (or release drugs along with genes) in a controlled sequence at different times or at different sites. This approach can lengthen gene expression periods, reduce the side effects of drugs, enhance the efficacy of drugs, and induce an anti-proliferative effect on cancer cells due to the synergistic effects of genes and drugs. The key objective of this review is to summarize recent progress in SR-based drug/gene delivery systems for cancer and other diseases.

The critical size of gold nanoparticles for overcoming P-gp mediated multidrug resistance

Multidrug resistance (MDR) remains a huge obstacle during cancer treatment. One of the most studied MDR mechanisms is P-glycoprotein (P-gp) mediated drug efflux. Based on the three-dimensional structural characteristics of P-gp, gold nanoparticles (AuNPs) with average sizes of 4.1 nm and 5.4 nm were designed for the construction of nanodrug delivery systems (NanoDDSs), with the anticancer molecules 2-(9-anthracenylmethylene)-hydrazinecarbothioamide (ANS) and 6-mercaptopurine (6-MP) modified on the AuNP surfaces through the thiol group. In vitro cytotoxicity results suggested that the larger sized AuNPs can effectively decrease the drug resistance index of MCF-7/ADR cells to ∼2. Verapamil and P-gp antibody competitive experiments, combined with the cellular uptake of AuNPs, indicated that larger NanoDDSs were more conducive to intracellular drug accumulation and thus had improved anticancer activities, due to a size mismatch between the nanoparticles and the active site of P-gp, and, therefore, reduced drug efflux was seen. Measurements of ATPase activity and intracellular ATP levels indicated that the larger nanoparticles do not bind well to P-gp, thus avoiding effective recognition by P-gp. This was further evidenced by the observation that 4.1 nm and 5.4 nm NanoDDS-treated MCF-7/ADR cells showed remarkable differences in energy-related metabolic pathways. Therefore, the critical size of AuNPs for overcoming MDR was identified to be between 4.1 nm and 5.4 nm. This provides a more accurate description of the composite dimension requirements for NanoDDSs that are designed to overcome MDR.

A combined "eat me/don't eat me" strategy based on extracellular vesicles for anticancer nanomedicine

A long-term and huge challenge in nanomedicine is the substantial uptake and rapid clearance mediated by the mononuclear phagocyte system (MPS), which enormously hinders the development of nanodrugs. Inspired by the natural merits of extracellular vesicles, we therefore developed a combined "eat me/don't eat me" strategy in an effort to achieve MPS escape and efficient drug delivery. Methodologically, cationized mannan-modified extracellular vesicles derived from DC2.4 cells were administered to saturate the MPS (eat me strategy). Then, nanocarriers fused to CD47-enriched exosomes originated from human serum were administered to evade phagocytosis by MPS (don't eat me strategy). The nanocarriers were also loaded with antitumor drugs and functionalized with a novel homing peptide to promote the tumour tissue accumulation and cancer cell uptake (eat me strategy). The concept was proven in vitro as evidenced by the reduced endocytosis of macrophages and enhanced uptake by tumour cells, whereas prolonged circulation time and increased tumour accumulation were demonstrated in vivo. Specially, the strategy induced a 123.53% increase in tumour distribution compared to conventional nanocarrier. The study both shed light on the challenge overcoming of phagocytic evasion and provided a strategy for significantly improving therapeutic outcomes, potentially permitting active drug delivery via targeted nanomedicines.

Aptamer-Based Targeted Drug Delivery Systems: Current Potential and Challenges

Aptamers are single-stranded DNA or RNA with 20-100 nucleotides in length that can specifically bind to target molecules via formed three-dimensional structures. These innovative targeting molecules have attracted an increasing interest in the biomedical field. Compared to traditional protein antibodies, aptamers have several advantages, such as small size, high binding affinity, specificity, good biocompatibility, high stability and low immunogenicity, which all contribute to their wide application in the biomedical field. Aptamers can bind to the receptors on the cell membrane and mediate themselves or conjugated nanoparticles to enter into cells. Therefore, aptamers can be served as ideal targeting ligands for drug delivery. Since their excellent properties, different aptamer-mediated drug delivery systems had been developed for cancer therapy. This review provides a brief overview of recent advances in drug delivery systems based on aptamers. The advantages, challenges and future prospectives are also discussed.

New strategy for precise cancer therapy: tumor-specific delivery of mitochondria-targeting photodynamic therapy agents and in situ O2-generation in hypoxic tumors

Besides tumor hypoxia and limitation of superficial lesions, the short lifetime of photoinduced reactive oxygen species (ROS) is another factor repressing photodynamic therapy (PDT) efficacy. To overcome these problems, this study developed newly designed mitochondria-specific, H₂O₂-activatable, and O₂-producing nanoparticles to achieve highly selective and efficient PDT and self-sufficiency of O₂ in hypoxic tumors. The newly designed nanoparticles (BDPP NPs) are composed of a mitochondria-targeting photosensitizer and catalase in the aqueous core and a black hole quencher and fluorescent tracker in the polymeric shell, and modified with the tumor-targeting cyclic pentapeptide c(RGDfK). Once taken up by α_vβ₃ integrin-rich tumor cells, intracellular H₂O₂ easily penetrated the lipophilic shells into the aqueous cores of BDPP NPs, and it was catalyzed by catalase to quickly generate O₂ gas, causing the rupture of the NPs to release the photosensitizer. Therefore in vivo tumor cell mitochondria targeting by BDPP can be realized together with the favorable hypoxia relief. In vitro and in vivo experiments demonstrate that the therapeutic efficiency was significantly improved by the mitochondria-specific feature and H₂O₂-controllable generation of ¹O₂. More importantly, BDPP NPs continuously generate O₂ in the PDT process, which can be helpful for resolving the overconsumption of oxygen in PDT and enhancing the PDT efficiency of cancer chemotherapy. We anticipate that this work may provide new insight into the design of smart PDT systems to achieve highly selective in vivo PDT via targeting subcellular organelles and realize oxygen therapy in O₂-deprived tumors.

Mitochondria-targeted drug delivery in cancers

Mitochondria are considered one of the most important subcellular organelles for targeting and delivering drugs because mitochondria are the main location for various cellular functions and energy (i.e., ATP) production, and mitochondrial dysfunctions and malfunctions cause diverse diseases such as neurodegenerative disorders, cardiovascular disorders, metabolic disorders, and cancers. In particular, unique mitochondrial characteristics (e.g., negatively polarized membrane potential, alkaline pH, high reactive oxygen species level, high glutathione level, high temperature, and paradoxical mitochondrial dynamics) in pathological cancers have been used as targets, signals, triggers, or driving forces for specific sensing/diagnosing/imaging of characteristic changes in mitochondria, targeted drug delivery on mitochondria, targeted drug delivery/accumulation into mitochondria, or stimuli-triggered drug release in mitochondria. In this review, we describe the distinctive structures, functions, and physiological properties of cancer mitochondria and discuss recent technologies of mitochondria-specific "key characteristic" sensing systems, mitochondria-targeted "drug delivery" systems, and mitochondrial stimuli-specific "drug release" systems as well as their strengths and weaknesses.

Programmed delivery of cyclopeptide RA-V and antisense oligonucleotides for combination therapy on hypoxic tumors and for therapeutic self-monitoring

Chemotherapy is a dominant treatment modality for different types and stages of cancer. However, hypoxia is one of the undesirable limitations of chemotherapy, which reduces the therapeutic efficiency in cancer treatment, ultimately leading to failure of the treatment. Herein, an ideal chemosensitization system capable of attenuating the tumor hypoxia microenvironment and enhancing chemotherapy effects in tumors was designed. This system (designated as the RA/RX Liposome) uses for the first time a pH-sensitive liposome to co-deliver cyclopeptide RA-V as chemotherapeutic drugs and antisense oligonucleotides as HIF-1α inhibitors (RX-0047) for attenuating tumor hypoxia, as well as a caspase-8 activation probe for therapeutic self-monitoring. After modification with death receptor 5-specific antibodies (anti-DR5) on the surface of the liposome, the RA/RX Liposome can successfully deliver components targeting colon tumors in vivo. This work should synergistically enhance the therapeutic effects of the treatment by successfully down-regulating HIF-1α expression against tumor hypoxia during the RA-V-induced apoptotic process. More importantly, the RA/RX Liposome can be precisely applied for therapeutic self-monitoring with the light-up fluorescence of the caspase-8 probe.

Sonodynamic Therapy Combined to 2-Deoxyglucose Potentiate Cell Metastasis Inhibition of Breast Cancer

Metastasis is a major dilemma of cancer therapy. It frequently occurs in breast cancer, which is the leading form of malignant tumor among females worldwide. Although there are therapies that provide a possible method for this challenge, such as chemotherapy, the tumoral metabolic pathway is unconventional and favors metastasis and proliferation. This magnifies the difficulty of treating breast cancer. In this study, we identified 2-deoxyglucose (2 DG) as an important glycolysis suppressor that can potentiate sonodynamic therapy (SDT) to inhibit migration and invasion. In addition, disruptions of the cell membrane microstructure were captured by a scanning electron microscope in cells treated with the co-therapy. Similarly, we detected blockages of the cell cycle process, using flow cytometry. Of note, we observed that hexokinase II (HK2), the rate-limiting enzyme of glycolysis, was notably uncoupled from the mitochondria in SDT + 2 DG co-therapy group. Furthermore, there was altered expression of HK2 and Glut1, which control glycolysis. Simultaneously, the in vivo results revealed that pulmonary metastasis was also seriously suppressed by SDT + 2 DG co-therapy. These results demonstrate this co-therapy is a promising strategy for breast cancer inhibition through metastasis and proliferation.

Graphene-Based Smart Platforms for Combined Cancer Therapy

The extensive research of graphene and its derivatives in biomedical applications during the past few years has witnessed its significance in the field of nanomedicine. Starting from simple drug delivery systems, the application of graphene and its derivatives has been extended to a versatile platform of multiple therapeutic modalities, including photothermal therapy, photodynamic therapy, magnetic hyperthermia therapy, and sonodynamic therapy. In addition to monotherapy, graphene-based materials are widely applied in combined therapies for enhanced anticancer activity and reduced side effects. In particular, graphene-based materials are often designed and fabricated as "smart" platforms for stimuli-responsive nanocarriers, whose therapeutic effects can be activated by the tumor microenvironment, such as acidic pH and elevated glutathione (termed as "endogenous stimuli"), or light, magnetic, or ultrasonic stimuli (termed as "exogenous stimuli"). Herein, the recent advances of smart graphene platforms for combined therapy applications are presented, starting with the principle for the design of graphene-based smart platforms in combined therapy applications. Next, recent advances of combined therapies contributed by graphene-based materials, including chemotherapy-based, photothermal-therapy-based, and ultrasound-therapy-based synergistic therapy, are outlined. In addition, current challenges and future prospects regarding this promising field are discussed.

SIRT3-Dependent Mitochondrial Dynamics Remodeling Contributes to Oxidative Stress-Induced Melanocyte Degeneration in Vitiligo

Mitochondrial dysregulation has been implicated in oxidative stress-induced melanocyte destruction in vitiligo. However, the molecular mechanism underlying this process is merely investigated. Given the prominent role of nicotinamide adenine dinucleotide (NAD⁺)-dependent deacetylase Sirtuin3 (SIRT3) in sustaining mitochondrial dynamics and homeostasis and that SIRT3 expression and activity can be influenced by oxidative stress-related signaling, we wondered whether SIRT3 could play an important role in vitiligo melanocyte degeneration by regulating mitochondrial dynamics.

Methods: We initially testified SIRT3 expression and activity in normal and vitiligo melanocytes via PCR, immunoblotting and immunofluorescence assays. Then, cell apoptosis, mitochondrial function and mitochondrial dynamics after SIRT3 intervention were analyzed by flow cytometry, immunoblotting, confocal laser microscopy, transmission electron microscopy and oxphos activity assays. Chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP), immunoblotting and immunofluorescence assays were performed to clarify the upstream regulatory mechanism of SIRT3. Finally, the effect of honokiol on protecting melanocytes and the underlying mechanism were investigated via flow cytometry and immunoblotting analysis.

Results: We first found that the expression and the activity of SIRT3 were significantly impaired in vitiligo melanocytes both in vitro and in vivo. Then, SIRT3 deficiency led to more melanocyte apoptosis by inducing severe mitochondrial dysfunction and cytochrome c release to cytoplasm, with Optic atrophy 1 (OPA1)-mediated mitochondrial dynamics remodeling involved in. Moreover, potentiated carbonylation and dampened peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) activation accounted for SIRT3 dysregulation in vitiligo melanocytes. Finally, we proved that honokiol could prevent melanocyte apoptosis under oxidative stress by activating SIRT3-OPA1 axis.

Conclusions: Overall, we demonstrate that SIRT3-dependent mitochondrial dynamics remodeling contributes to oxidative stress-induced melanocyte degeneration in vitiligo, and honokiol is promising in preventing oxidative stress-induced vitiligo melanocyte apoptosis.

Redox Dual-Responsive and O2‑Evolving Theranostic Nanosystem for Highly Selective Chemotherapy against Hypoxic Tumors

Activatable theranostic agents, which combine fluorescent reporters with masked chemotherapeutic agents that are activated by tumor-associated stimuli, would be attractive candidates to improve the tumor selectivity of chemotherapy. This work reports a ROS/GSH dual-activatable and O2‑evolving theranostic nanosystem (RA-S-S-Cy@PLGA NPs) for highly selective therapy against hypoxic tumors and in situ fluorescence-tracking of cancer chemotherapy. Methods: In this system, the newly designed theranostic agent (RA-S-S-Cy) is composed of a disulfide bond as a cleavable linker, a near infrared (NIR) active fluorophore as a fluorescent tracker, and a natural cyclopeptide RA-V as the active anti-cancer agent. Upon reaction with the high level of intracellular glutathione (GSH), disulfide cleavage occurs, resulting in concomitant active drug RA-V release and significant NIR fluorescence increase. To further improve the tumor targeting of RA-S-S-Cy and achieve redox dual-responsiveness, RA-S-S-Cy was incorporated into the c(RGDfK)-targeted PLGA nanoparticles together with an O2-generating agent (catalase) to produce RA-S-S-Cy@PLGA NPs. Results: The cell-specific and redox dual-activatable release of RA-V lead to enhanced therapeutic outcomes in vivo and in vitro. More significantly, the RA-S-S-Cy@PLGA NPs were successfully applied for monitoring of drug release and chemotherapeutic efficacy in situ by "turn-on" NIR fluorescence. Conclusions: RA-S-S-Cy@PLGA NPs would be efficient theranostic nanosystems for more precise therapy against hypoxic tumors and provides a potential tool for deeper understanding of drug release mechanisms.

HSA-based multi-target combination therapy: regulating drugs' release from HSA and overcoming single drug resistance in a breast cancer model

Multi-drug delivery systems, which may be promising solution to overcome obstacles, have limited the clinical success of multi-drug combination therapies to treat cancer. To this end, we used three different anticancer agents, Cu(BpT)Br, NAMI-A, and doxorubicin (DOX), to build human serum albumin (HSA)-based multi-drug delivery systems in a breast cancer model to investigate the therapeutic efficacy of overcoming single drug (DOX) resistance to cancer cells in vivo, and to regulate the drugs' release from HSA. The HSA complex structure revealed that NAMI-A and Cu(BpT)Br bind to the IB and IIA sub-domain of HSA by N-donor residue replacing a leaving group and coordinating to their metal centers, respectively. The MALDI-TOF mass spectra demonstrated that one DOX molecule is conjugated with lysine of HSA by a pH-sensitive linker. Furthermore, the release behavior of three agents form HSA can be regulated at different pH levels. Importantly, in vivo results revealed that the HSA-NAMI-A-Cu(BpT)Br-DOX complex not only increases the targeting ability compared with a combination of the three agents (the NAMI-A/Cu(BpT)Br/DOX mixture), but it also overcomes DOX resistance to drug-resistant breast cancer cell lines.

Dimeric BODIPY-loaded liposomes for dual hypoxia marker imaging and activatable photodynamic therapy against tumors

This work reports a dimeric BODIPY (BDP)-loaded liposome with conjugation of anti-HIF antibodies for dual hypoxia marker imaging and nitroreductase (NTR)-activatable photodynamic therapy (PDT) against hypoxic tumors.