Amplification of oxidative stress by a dual stimuli-responsive hybrid drug enhances cancer cell death

Photo-activatable prodrug nanoparticles for reactive oxygen species amplification and cooperative cancer therapy

Photodynamic therapy (PDT), as a minimally invasive cancer therapy, demonstrates certain advantages in treating superficial tumors. However, it often faces challenges such as low reactive oxygen species (ROS) generation efficiency and non-targeted distribution of photosensitizers. The combination of chemotherapy and PDT can address the limitations of single modal therapies and improve therapeutic outcomes. In this work, we design a prodrug-based nanomedicine that can achieve photo-activated cascade drug release. Under 660 nm laser irradiation, the generated singlet oxygen can trigger the release of chemotherapeutic agent chlorambucil, cinnamaldehyde and quinone methyl. Chlorambucil can exert anti-tumor effects and cinnamaldehyde can increase intracellular hydrogen peroxide levels, while quinone methyl can consume intracellular glutathione. This process ultimately results in the amplification of ROS signals and further activation of prodrugs. This nanomedicine exhibits the ability to amplify oxidative stress and potent anticancer activity. In vivo experiments show that the nanomedicine can effectively inhibit tumor growth. This work provides a promising mutually beneficial strategy for achieving cooperative cancer therapy.

Targeting matrix metalloproteinases activating and indoleamine 2,3-dioxygenase suppression for triple-negative breast cancer multimodal therapy

The dense extracellular matrix (ECM) and immunosuppressive tumor microenvironment represent two major challenges in the treatment of triple-negative breast cancer (TNBC). To address these obstacles, this study has developed a polymer micelle (NTP) for ECM remodeling and mitigation the immune microenvironment, based on activating endogenous matrix metalloproteinases (MMP) and suppression indoleamine 2,3-dioxygenase (IDO). Through self-assembly technology, this micelle effectively incorporates chemotherapy drugs (camptothecin (CPT) and cinnamaldehyde (CA)), reactive oxygen species (ROS) stimulants, nitric oxide (NO) donor and IDO inhibitor (NLG919), where CPT and CA have been reported to help generating ROS mainly in the mitochondrion. The guanidine group of poly-L-arginine (PArg), as an NO donor, can react with ROS to generate NO. The micelles aim to achieve significant therapeutic outcomes through robust drug penetration and anti-tumor immunity in multimodal therapy. They exhibit remarkable tumor tissue penetration ability, facilitating precise targeting of mitochondria and ROS production stimulation. Building upon this therapeutic foundation, the micellar system achieves in situ NO release, which effectively degrades the ECM through the activation of MMPs, while simultaneously promoting tumor cells apoptosis. Furthermore, the encapsulated NLG919 can be released and effectively mitigating the immunosuppressive milieu and triggering anti-tumor immune responses. Experimental results demonstrate that the micelles exhibit significant anti-tumor effects both in vitro and in vivo, accompanied by favorable biocompatibility. This study provides new insights into the application of subcellular targeting drug delivery systems in TNBC treatment, potentially heralding a new breakthrough in TNBC therapy.

Stimuli-Responsive Prodrug Linkers That Simultaneously Release Cargo and Neutralize In Situ Generated (Aza)Quinone Methides

Self-immolative linkers that use p-amino/hydroxy-benzyloxycarbonyl (PABC/PHBC) spacers are essential to the mechanism of many prodrugs. However, a highly reactive (aza)quinone methide is generated as a potential toxic byproduct. To remove the methide as it forms, we synthesized a series of novel tripartite prodrugs, comprising different triggers (nitro, amide, azide, boronate) and a PABC/PHBC-type self-immolative spacer with an integrated nucleophile (amine). Upon reductive, hydrolytic, or oxidative-trigger activation, the release of the cargo is facilitated via a 1,6-elimination that generates a reactive (aza)quinone methide. With the built-in nucleophile, the (aza)quinone methide is rapidly self-quenched to generate tetrahydroisoquinolines (THIQs). One of the selected THIQs does not exhibit an anti-proliferative effect on the A431 mammalian tumor cell line. The new prodrug strategy has broad scope, enabling the use of a trigger that matches the targeted stimulus, while allowing for a diverse range of drug/cargo attachment. This proof-of-concept study adds a new linker strategy that quenches the electrophilic (aza)quinone methide generated in many self-immolative linker systems and could find applications in prodrug and antibody-drug conjugate strategies, or as a linker for probes in chemical biology.

siRNA-based Therapeutics in Hormone-driven Cancers: Advancements and benefits over conventional treatments

Hormone-related cancers, also known as hormone-sensitive or hormone-dependent cancers, rely on hormones such as estrogen, testosterone, and progesterone for growth. These malignancies, including breast, pituitary, thyroid, ovarian, uterine, cervical, and prostate cancers, often exhibit accelerated progression in response to hormonal signaling. Small interfering RNA (siRNA) has emerged as a groundbreaking gene suppression therapy since the FDA approval of its first product in 2018. With over 200 ongoing clinical trials, siRNA is being actively explored as a targeted treatment for hormone-related cancers. Its ability to silence specific oncogenes offers significant advantages over conventional therapies, which are often associated with toxicity, resistance, and non-specific targeting. However, challenges in siRNA delivery remain a major barrier to its clinical translation, limiting its ability to reach target cells effectively. This review evaluates the potential of siRNA in hormone-related cancers, addressing the shortcomings of traditional treatments while examining novel strategies to enhance siRNA delivery and overcome tumor microenvironment obstacles. Notably, no existing literature comprehensively consolidates siRNA-based therapies for these cancers, emphasizing the importance of this manuscript in bridging current knowledge gaps and advancing the translational application of siRNA therapeutics.

A covalent organic framework-based nanoreactor for enhanced chemodynamic therapy through cascaded Fenton-like reactions and nitric oxide delivery

Herein, we report a nanoscale composite COF material loaded with copper peroxide (CuO2) and nitric oxide (NO) prodrug via a stepwise post-synthetic modification. The obtained CuO2@COF-SNO can undergo a cascade reaction in the tumor microenvironment to generate reactive oxygen and nitrogen species (ROS/RNS) to enhance chemodynamic therapy of the tumor.

Black phosphorus-based nanoplatforms for cancer therapy: chemistry, design, biological and therapeutic behaviors

Cancer, a significant threat to human lives, has been the target of research for several decades. Although conventional therapies have drawbacks, such as side effects, low efficacy, and weak targeting, they have been applied extensively due to a lack of effective alternatives. The emergence of nanotechnology in medicine has opened up new possibilities and offered promising solutions for cancer therapy. In recent years, 2D nanomaterials have attracted enormous attention in nanomedicine due to their large surface-to-volume ratio, photo-responsivity, excellent electrical conductivity, etc. Among them, black phosphorus (BP) is a 2D nanomaterial consisting of multiple layers weakly bonded together through van der Waals forces. Its distinct structure makes BP suitable for biomedical applications, such as drug/gene carriers, PTT/PDT, and imaging agents. BP has demonstrated remarkable potential since its introduction in cancer therapy in 2015, particularly due to its selective anticancer activity even without the aid of near-infrared (NIR) or anticancer drugs. The present review makes efforts to cover and discuss studies published on the anticancer activity of BP. Based on the type of cancer, the subcategories are organized to shed light on the potential of BP nanosheets and BP quantum dots (BPQDs) against breast, brain, skin, prostate, and bone cancers, and a section is devoted to other cancer types. Since extensive attention has been paid to breast cancer cells and in vivo models, various subsections, including mono-, dual, and triple therapeutic approaches are established for this cancer type. Furthermore, the review outlines various synthesis approaches employed to produce BP nanomaterials, providing insights into key synthesis parameters. This review provides an up-to-date platform for the potential reader to understand what has been done about BP cancer therapy based on each disease, and the conclusions and outlook cover the directions in which this approach is going to proceed in the future.

Harnessing Dual-Responsive Polymeric Micelles for Precision Oxidative Stress Amplification in Targeted Cancer Therapy

Targeting the altered redox balance in cancer cells, this study explores a strategy to induce selective cancer cell death by combining reactive oxygen species (ROS) generation with glutathione (GSH) depletion. We developed oxidative stress-amplifying polymeric (pCB) micelles that function both as therapeutic agents and carriers for GSH-depleting retinoic acid prodrug (BRDP). pCB incorporating ROS-generating cinnamaldehyde and a GSH-depleting quinone methide precursor could self-assemble into micelles encapsulating BRDP, delivering both ROS generators and GSH-depleting drugs. The micelles were surface-functionalized with the tripeptide Arg-Gly-Asp (RGD) for targeted delivery to integrin-overexpressing tumors. In a mouse xenograft model, RGD-decorated BRDP-loaded micelles significantly accumulated in tumor sites, enhancing anticancer efficacy without toxicity to normal tissues. This study marks significant advancement in the field of oxidative stress-amplifying polymeric precursors, presenting a novel and highly effective anticancer therapeutic approach that integrates multiple tumor-specific triggers and ROS-mediated mechanisms.

Nanozyme as Tumor Energy Homeostasis Disruptor to Augment Cascade Catalytic Therapy

Breaking the balance of the tumor microenvironment and reshaping it sustainably remain major challenges in lung cancer treatment. Here, a "tumor energy homeostasis disruptor", the Cu2O@Au nanozyme was developed, which exhibits excellent glucose oxidase-like activity, enabling it to be used for starvation therapy and as a mimic peroxidase for chemodynamic therapy (CDT), producing •OH. Cu2O@Au nanozymes consume glucose at the tumor site to block the tumor's energy supply, produce H2O2 continuously, and lower the pH to enhance the efficiency of CDT, initiating a cascade reaction that leads to a storm of reactive oxygen species (ROS). Furthermore, Cu2O@Au nanozyme consumes glutathione and reduces the expression of the SLC7A11 (xCT) protein to decrease cancer cell uptake of cysteine, further enhancing the burst of ROS, resulting in lipid peroxidation in tumor cells and ultimately leading to ferroptosis. The excellent photothermal performance of Cu2O@Au can further enhance CDT. Additionally, Cu2O@Au nanozyme also has computed tomography (CT) and photothermal imaging capabilities. In conclusion, Cu2O@Au nanozymes, acting as tumor energy homeostasis disruptor, can effectively inhibit tumor growth and successfully achieve the synergistic effects of starvation therapy/CDT/photothermal therapy (PTT). This multifunctional nanozyme holds promise for providing valuable insights and therapeutic strategies for cancer treatment.

Boronate-Based Bioactive Compounds Activated by Peroxynitrite and Hydrogen Peroxide

Boronates react directly and stoichiometrically with peroxynitrite and hydrogen peroxide. For this reason, boronates have been widely used as peroxynitrite- and hydrogen peroxide-sensitive moieties in various donors of bioactive compounds. So far, numerous boronate-based prodrugs and theranostics have been developed, characterized, and used in biological research. Here, the kinetic aspects of their activation are discussed, and the potential benefits of modifying their original structure with a boronic or boronobenzyl moiety are described.

Multifunctional scaffolds for bone repair following age-related biological decline: Promising prospects for smart biomaterial-driven technologies

The repair of large bone defects due to trauma, disease, and infection can be exceptionally challenging in the elderly. Despite best clinical practice, bone regeneration within contemporary, surgically implanted synthetic scaffolds is often problematic, inconsistent, and insufficient where additional osteobiological support is required to restore bone. Emergent smart multifunctional biomaterials may drive important and dynamic cellular crosstalk that directly targets, signals, stimulates, and promotes an innate bone repair response following age-related biological decline and when in the presence of disease or infection. However, their role remains largely undetermined. By highlighting their mechanism/s and mode/s of action, this review spotlights smart technologies that favorably align in their conceivable ability to directly target and enhance bone repair and thus are highly promising for future discovery for use in the elderly. The four degrees of interactive scaffold smartness are presented, with a focus on bioactive, bioresponsive, and the yet-to-be-developed autonomous scaffold activity. Further, cell- and biomolecular-assisted approaches were excluded, allowing for contemporary examination of the capabilities, demands, vision, and future requisites of next-generation biomaterial-induced technologies only. Data strongly supports that smart scaffolds hold significant promise in the promotion of bone repair in patients with a reduced osteobiological response. Importantly, many techniques have yet to be tested in preclinical models of aging. Thus, greater clarity on their proficiency to counteract the many unresolved challenges within the scope of aging bone is highly warranted and is arguably the next frontier in the field. This review demonstrates that the use of multifunctional smart synthetic scaffolds with an engineered strategy to circumvent the biological insufficiencies associated with aging bone is a viable route for achieving next-generation therapeutic success in the elderly population.

Nanomaterial-based regulation of redox metabolism for enhancing cancer therapy

Altered redox metabolism is one of the hallmarks of tumor cells, which not only contributes to tumor proliferation, metastasis, and immune evasion, but also has great relevance to therapeutic resistance. Therefore, regulation of redox metabolism of tumor cells has been proposed as an attractive therapeutic strategy to inhibit tumor growth and reverse therapeutic resistance. In this respect, nanomedicines have exhibited significant therapeutic advantages as intensively reported in recent studies. In this review, we would like to summarize the latest advances in nanomaterial-assisted strategies for redox metabolic regulation therapy, with a focus on the regulation of redox metabolism-related metabolite levels, enzyme activity, and signaling pathways. In the end, future expectations and challenges of such emerging strategies have been discussed, hoping to enlighten and promote their further development for meeting the various demands of advanced cancer therapies. It is highly expected that these therapeutic strategies based on redox metabolism regulation will play a more important role in the field of nanomedicine.

Potent and Selective Oxidatively Labile Ether-Based Prodrugs through Late-Stage Boronate Incorporation

This manuscript describes a new strategy for prodrug synthesis in which a relatively inert ether group is introduced at an early stage in a synthetic sequence and functionalized in the final step to introduce a prodrug-activating group through a chemoselective process. Boryl allyloxy (BAO) ether groups are synthesized through several metal-mediated processes to form entities that are readily cleaved under oxidative conditions commonly found in cancer cells. The high cleavage propensity of the BAO group allows for ether cleavage, making these compounds substantially more hydrolytically stable in comparison to acyl-linked prodrugs while retaining the ability to release alcohols. We report the preparation of prodrug analogues of the natural products camptothecin and pederin from acetal precursors that serve as protecting groups in their synthetic sequences. The BAO acetal groups cleave in the presence of hydrogen peroxide to release the cytotoxic agents. The pederin-based prodrug shows dramatically greater cytotoxicity than negative controls and outstanding selectivity and potency toward cancer cell lines in comparison to non-cancerous cell lines. This late-stage functionalization approach to prodrug synthesis should be applicable to numerous systems that can be accessed through chemoselective processes.

Ultrasmall Metal TPZ Complexes with Deep Tumor Penetration for Enhancing Radiofrequency Ablation Therapy and Inducing Antitumor Immune Responses

Radiofrequency ablation (RFA) is one of the most common minimally invasive techniques for the treatment of solid tumors, but residual malignant tissues or small satellite lesions after insufficient RFA (iRFA) are difficult to remove, often leading to metastasis and recurrence. Here, Fe-TPZ nanoparticles are designed by metal ion and (TPZ) ligand complexation for synergistic enhancement of RFA residual tumor therapy. Fe-TPZ nanoparticles are cleaved in the acidic microenvironment of the tumor to generate Fe2+ and TPZ. TPZ, an anoxia-dependent drug, is activated in residual tumors and generates free radicals to cause tumor cell death. Elevated Fe2+ undergoes a redox reaction with glutathione (GSH), inducing a strong Fenton effect and promoting the production of the highly toxic hydroxyl radical (•OH). In addition, the ROS/GSH imbalance induced by this treatment promotes immunogenic cell death (ICD), which triggers the release of damage-associated molecular patterns, macrophage polarization, and lymphocyte infiltration, thus triggering a systemic antitumor immune response and noteworthy prevention of tumor metastasis. Overall, this integrated treatment program driven by multiple microenvironment-dependent pathways overcomes the limitations of the RFA monotherapy approach and thus improves tumor prognosis. Furthermore, these findings aim to provide new research ideas for regulating the tumor immune microenvironment.

Rationally designed catalytic nanoplatform for enhanced chemoimmunotherapy via deploying endogenous plus exogenous copper and remodeling tumor microenvironment

Chemodynamic therapy represents a novel tumor therapeutic modality via triggering catalytic reactions in tumors to yield highly toxic reactive oxygen species (ROS). Nevertheless, low efficiency catalytic ability, potential systemic toxicity and inefficient tumor targeting, have hindered the efficacy of chemodynamic therapy. Herein, a rationally designed catalytic nanoplatform, composed of folate acid conjugated liposomes loaded with copper peroxide (CP) and chloroquine (CQ; a clinical drug) (denoted as CC@LPF), could power maximal tumor cytotoxicity, mechanistically via maneuvering endogenous and exogenous copper for a highly efficient catalytic reaction. Despite a massive autophagosome accumulation elicited by CP-powered autophagic initiation and CQ-induced autolysosomal blockage, the robust ROS, but not aberrant autophagy, underlies the synergistic tumor inhibition. Otherwise, this combined mode also elicits an early onset, above all, long-term high-level existence of immunogenic cell death markers, associated with ROS and aberrant autophagy -triggered endoplasmic reticulum stress. Besides, CC@LPF, with tumor targeting capability and selective tumor cytotoxicity, could elicit intratumor dendritic cells (mainly attributed to CQ) and tumor infiltrating CD8+ T cells, upon combining with PD-L1 therapeutic antibody, further induce significant anti-tumor effect. Collectively, the rationally designed nanoplatform, CC@LPF, could enhance tumor chemoimmunotherapy via deploying endogenous plus exogenous copper and remodeling tumor microenvironment.

A nanocarbon-enabled hybridization strategy to construct pharmacologically cooperative therapeutics for augmented anticancer efficacy

The drug design principles are of great value in developing nanomedicines with favorable functionalities. Herein we propose a nanocarbon-enabled hybridization strategy to construct a pharmacologically cooperative nanodrug for improved cancer therapy in the light of pharmacophore hybridization in medicinal chemistry and the synthetic principles of nanocarbons. An antioxidant defense pharmacological inhibitor and a co-nucleation precursor are structurally hybridized into nanodrugs (SCACDs) via forming carbon quantum dots. These SCACDs elicit dual enhanced bioactivities, including superior sonocatalytic activity that arose from the appropriate band structure of the pharmacophoric carbon cores, and more than an order of magnitude higher antioxidant defense inhibitory activity than the pharmacological inhibitor via conveying the bioactive pharmacophores from the molecular level to nanoscale. In vivo, SCACDs possess a long body retention and desirable biodistribution to eliminate melanoma cells at a very low injection dose. The present study provides a viable yet effective strategy for the development of pharmacologically cooperative nanodrugs to achieve remarkably improved therapeutic efficacy.

Mitochondria-mediated self-cycling nanoreactor enabling uninterrupted oxidative damage for enhanced chemodynamic therapy

Chemodynamic therapy (CDT), which employs intracellular H2O2 to produce toxic hydroxyl radicals to kill cancer cells, has received great attention due to its specificity to tumors. However, the relatively insufficient endogenous H2O2 and the short-lifetime and limited diffusion distance of •OH compromise the therapeutic efficacy of CDT. Mitochondria, which play crucial roles in oncogenesis, are highly vulnerable to elevated oxidative stress. Herein, we constructed a mitochondria-mediated self-cycling system to achieve high dose of •OH production through continuous H2O2 supply. Cinnamaldehyde (CA), which can elevate H2O2 level in the mitochondria, was loaded in Cu(II)-containing metal organic framework (MOF), termed as HKUST-1. After actively targeting mitochondria, the intrinsic H2O2 in mitochondria of cancer cells could induce degradation of MOF, releasing the initial free CA. The released CA further triggered the upregulation of endogenous H2O2, resulting in the subsequent adequate release of CA and the final burst growth of H2O2. The cycle process greatly promoted the Fenton-like reaction between Cu2+ and H2O2 and induced long-term high oxidative stress, achieving enhanced chemodynamic therapy. In a word, we put forward an efficient strategy for enhanced chemodynamic therapy.

Totally Caged Type I Pro-Photosensitizer for Oxygen-Independent Synergistic Phototherapy of Hypoxic Tumors

Activatable type I photosensitizers are an effective way to overcome the insufficiency and imprecision of photodynamic therapy in the treatment of hypoxic tumors, however, the incompletely inhibited photoactivity of pro-photosensitizer and the limited oxidative phototoxicity of post-photosensitizer are major limitations. It is still a great challenge to address these issues using a single and facile design. Herein, a series of totally caged type I pro-photosensitizers (Pro-I-PSs) are rationally developed that are only activated in tumor hypoxic environment and combine two oxygen-independent therapeutic mechanisms under single-pulse laser irradiation to enhance the phototherapeutic efficacy. Specifically, five benzophenothiazine-based dyes modified with different nitroaromatic groups, BPN 1-5, are designed and explored as latent hypoxia-activatable Pro-I-PSs. By comparing their optical responses to nitroreductase (NTR), it is identified that the 2-methoxy-4-nitrophenyl decorated dye (BPN 2) is the optimal Pro-I-PSs, which can achieve NTR-activated background-free fluorescence/photoacoustic dual-modality tumor imaging. Furthermore, upon activation, BPN 2 can simultaneously produce an oxygen-independent photoacoustic cavitation effect and a photodynamic type I process at single-pulse laser irradiation. Detailed studies in vitro and in vivo indicated that BPN 2 can effectively induce cancer cell apoptosis through synergistic effects. This study provides promising potential for overcoming the pitfalls of hypoxic-tumor photodynamic therapy.

K. P, Kim CH, Li Y, Park JH. Dual Stimuli-Responsive Nanoprecursor of Ascorbic Acid and Quinone Methide Disrupting Redox Homeostasis for Cancer Treatment

Disrupting the redox balance through reactive oxygen species (ROS) generation and intracellular glutathione (GSH) depletion presents a promising strategy for cancer therapy. Megadoses of ascorbic acid (AA) can induce oxidative stress in cancer cells, leading to cell death. However, achieving enhanced oxidative stress using ultrahigh doses of AA is challenging because of the intricate delivery of high-concentration AA to the targeted sites while the cancer cells could also re-establish more robust redox homeostasis by upregulating antioxidants such as GSH. Recently, quinone methide and its analogues (QMs) have been recognized as effective GSH scavengers, offering a new dimension to accelerate oxidative stress. In this study, we formulated a dual stimuli-responsive nanoprecursor of AA and QM using gold nanoparticles. The nanoprecursor can release AA in response to the intracellular acidic pH in tumor cells, elevating the intracellular ROS levels and triggering the production of ample QMs to quench excessive GSH. This positive feedback mechanism significantly amplifies oxidative stress and disrupts redox homeostasis in cancer cells at a relatively low concentration of AA, leading to selective apoptosis without affecting normal cells. These results highlight the potential of the nanoprecursor as an effective anticancer therapeutic.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)-Sensitive Triggers

Reactive oxygen species (ROS) are critical for cellular signaling. Various pathophysiological conditions are also associated with elevated levels of ROS. Hence, ROS-sensitive triggers have been extensively used for selective payload delivery. Such applications are predicated on two key functions: (1) a sufficient magnitude of concentration difference for the interested ROS between normal tissue/cells and intended sites and (2) appropriate reaction kinetics to ensure a sufficient level of selectivity for payload release. Further, ROS refers to a group of species with varying reactivity, which should not be viewed as a uniform group. In this review, we critically analyze data on the concentrations of different ROS species under various pathophysiological conditions and examine how reaction kinetics affect the success of ROS-sensitive linker chemistry. Further, we discuss different ROS linker chemistry in the context of their applications in drug delivery and imaging. This review brings new insights into research in ROS-triggered delivery, highlights factors to consider in maximizing the chance for success and discusses pitfalls to avoid.

ROS-responsive and triple-synergistic mitochondria-targeted polymer micelles for efficient induction of ICD in tumor therapeutics

Immunogenic cell death (ICD) represents a modality of apoptosis distinguished by the emanation of an array of damage-related molecular signals. This mechanism introduces a novel concept in the field of contemporary tumor immunotherapy. The inception of reactive oxygen species (ROS) within tumor cells stands as the essential prerequisite and foundation for ICD induction. The formulation of highly efficacious photodynamic therapy (PDT) nanomedicines for the successful induction of ICD is an area of significant scientific inquiry. In this work, we devised a ROS-responsive and triple-synergistic mitochondria-targeted polymer micelle (CAT/CPT-TPP/PEG-Ce6, CTC) that operates with multistage amplification of ROS to achieve the potent induction of ICD. Utilizing an "all-in-one" strategy, we direct both the PDT and chemotherapeutic units to the mitochondria. Concurrently, a multistage cyclical amplification that caused by triple synergy strategy stimulates continuous, stable, and adequate ROS generation (domino effect) within the mitochondria of cells. Conclusively, influenced by ROS, tumor cell-induced ICD is effectively activated, remodeling immunogenicity, and enhancing the therapeutic impact of PDT when synergized with chemotherapy. Empirical evidence from in vitro study substantiates that CTC micelles can efficiently provoke ICD, catalyzing CRT translocation, the liberation of HMGB1 and ATP. Furthermore, animal trials corroborate that polymer micelles, following tail vein injection, can induce ICD, accumulate effectively within tumor tissues, and markedly inhibit tumor growth subsequent to laser irradiation. Finally, transcriptome analysis was carried out to evaluate the changes in tumor genome induced by CTC micelles. This work demonstrates a novel strategy to improve combination immunotherapy using nanotechnology.

Dual-Responsive Supramolecular Polymeric Nanomedicine for Self-Cascade Amplified Cancer Immunotherapy

Insufficient tumor immunogenicity and immune escape from tumors remain common problems in all tumor immunotherapies. Recent studies have shown that pyroptosis, a form of programmed cell death that is accompanied by immune checkpoint inhibitors, can induce effective immunogenic cell death and long-term immune activation. Therapeutic strategies to jointly induce pyroptosis and reverse immunosuppressive tumor microenvironments are promising for cancer immunotherapy. In this regard, a dual-responsive supramolecular polymeric nanomedicine (NCSNPs) to self-cascade amplify the benefits of cancer immunotherapy is designed. The NCSNPs are formulated by β-cyclodextrin coupling nitric oxide (NO) donor, a pyroptosis activator, and NLG919, an indoleamine 2,3-dioxygenase (IDO) inhibitor, and self-assembled through host-guest molecular recognition and hydrophobic interaction to obtain nanoparticles. NCSNPs possess excellent tumor accumulation and bioavailability attributed to ingenious supramolecular engineering. The study not only confirms the occurrence of NO-triggered pyroptosis in tumors for the first time but also reverses the immunosuppressive microenvironment in tumor sites via an IDO inhibitor by enhancing the infiltration of cytotoxic T lymphocytes, to achieve remarkable inhibition of tumor proliferation. Thus, this study provides a novel strategy for cancer immunotherapy.

Antioxidant network-based signatures cluster glioblastoma into distinct redox-resistant phenotypes

Introduction

Aberrant reactive oxygen species (ROS) production is one of the hallmarks of cancer. During their growth and dissemination, cancer cells control redox signaling to support protumorigenic pathways. As a consequence, cancer cells become reliant on major antioxidant systems to maintain a balanced redox tone, while avoiding excessive oxidative stress and cell death. This concept appears especially relevant in the context of glioblastoma multiforme (GBM), the most aggressive form of brain tumor characterized by significant heterogeneity, which contributes to treatment resistance and tumor recurrence. From this viewpoint, this study aims to investigate whether gene regulatory networks can effectively capture the diverse redox states associated with the primary phenotypes of GBM.

Methods

In this study, we utilized publicly available GBM datasets along with proprietary bulk sequencing data. Employing computational analysis and bioinformatics tools, we stratified GBM based on their antioxidant capacities and evaluated the distinctive functionalities and prognostic values of distinct transcriptional networks in silico.

Results

We established three distinct transcriptional co-expression networks and signatures (termed clusters C1, C2, and C3) with distinct antioxidant potential in GBM cancer cells. Functional analysis of each cluster revealed that C1 exhibits strong antioxidant properties, C2 is marked with a discrepant inflammatory trait and C3 was identified as the cluster with the weakest antioxidant capacity. Intriguingly, C2 exhibited a strong correlation with the highly aggressive mesenchymal subtype of GBM. Furthermore, this cluster holds substantial prognostic importance: patients with higher gene set variation analysis (GSVA) scores of the C2 signature exhibited adverse outcomes in overall and progression-free survival.

Conclusion

In summary, we provide a set of transcriptional signatures that unveil the antioxidant potential of GBM, offering a promising prognostic application and a guide for therapeutic strategies in GBM therapy.

Macromolecular Cargo Encapsulation via In Vitro Assembly of Two-Component Protein Nanoparticles

Self-assembling protein nanoparticles are a promising class of materials for targeted drug delivery. Here, the use of a computationally designed, two-component, icosahedral protein nanoparticle is reported to encapsulate multiple macromolecular cargoes via simple and controlled self-assembly in vitro. Single-stranded RNA molecules between 200 and 2500 nucleotides in length are encapsulated and protected from enzymatic degradation for up to a month with length-dependent decay rates. Immunogenicity studies of nanoparticles packaging synthetic polymers carrying a small-molecule TLR7/8 agonist show that co-delivery of antigen and adjuvant results in a more than 20-fold increase in humoral immune responses while minimizing systemic cytokine secretion associated with free adjuvant. Coupled with the precise control over nanoparticle structure offered by computational design, robust and versatile encapsulation via in vitro assembly opens the door to a new generation of cargo-loaded protein nanoparticles that can combine the therapeutic effects of multiple drug classes.

Selective Manipulation of the Mitochondria Oxidative Stress in Different Cells Using Intelligent Mesoporous Silica Nanoparticles to Activate On-Demand Immunotherapy for Cancer Treatment

Herein, the vitamin K2 (VK2)/maleimide (MA) coloaded mesoporous silica nanoparticles (MSNs), functional molecules including folic acid (FA)/triphenylphosphine (TPP)/tetrapotassium hexacyanoferrate trihydrate (THT), as well as CaCO3 are explored to fabricate a core-shell-corona nanoparticle (VMMFTTC) for on-demand anti-tumor immunotherapy. After application, the tumor-specific acidic environment first decomposed CaCO3 corona, which significantly levitates the pH value of tumor tissue to convert M2 type macrophage to the antitumor M1 type. The resulting VMMFTT would then internalize in both tumor cells and macrophages via FA-assisted endocytosis and free endocytosis, respectively. These distinct processes generate different amount of VMMFTT in above two cells followed by 1) TPP-induced accumulation in the mitochondria, 2) THT-mediated effective capture of various signal ions to cut off signal transmission and further inhibit glutathione (GSH) generation, 3) ions catalyzed reactive oxygen species (ROS) production through Fenton reaction, 4) sustained release of VK2 and MA to further enhance the ROS production and GSH depletion, which caused significant apoptosis of tumor cells and additional M2-to-M1 macrophage polarization via different processes of oxidative stress. Moreover, the primary tumor apoptosis further matures surrounding immature dendritic cells and activates T cells to continuously promote the antitumor immunotherapy.

Glycosidase-activated H2S donorsto enhance chemotherapy efficacy

Hydrogen sulfide (H2S) plays a critical role in cancer biology. Herein, we developed a series of glycosidase-triggered hydrogen sulfide (H2S) donors by connecting sugar moieties (including glucose, galactose and mannose) to COS donors via a self-immolative spacer. In the presence of corresponding glycosidases, H2S was gradually released from these donors in PBS buffer with releasing efficiencies from 36 to 67 %. H2S release was also detected by H2S probe WSP-1 after treatment HepG2 cells with Man1. Cytotoxicities of these glycosylated H2S donors were evaluated against HepG2 by MTT assay. Among them, Man1 and Man2 exhibited an obvious reduction of cell viability in HepG2 cells, with cell viability as 37.6 % for 80 μM of Man. Consistently, significant apoptosis was observed in HepG2 cells after treatment with Man1 and Man2. Finally, We evaluated the potential of Man1 for combination therapy with doxorubicin. A synergistic effect was observed between Man1 and Doxorubicin in HepG2 and Hela cells. All these results indicated glycosidase-activated H2S donorshave promising potential for cancer therapy.

Enzyme-Activatable Near-Infrared Photosensitizer with High Enrichment in Tumor Cells Based on a Multi-Effect Design

Enzyme-activatable near-infrared (NIR) fluorescent probes and photosensitizers (PSs) have emerged as promising tools for molecular imaging and photodynamic therapy (PDT). However, in living organisms selective retention or even enrichment of these reagents after enzymatic activation at or near sites of interest remains a challenging task. Herein, we integrate non-covalent and covalent retention approaches to introduce a novel "1-to-3" multi-effect strategy-one enzymatic stimulus leads to three types of effects-for the design of an enzyme-activatable NIR probe or PS. Using this strategy, we have constructed an alkaline phosphatase (ALP)-activatable NIR fluorogenic probe and a NIR PS, which proved to be selectively activated by ALP to switch on NIR fluorescence or photosensitizing ability, respectively. Additionally, these reagents showed significant enrichment (over 2000-fold) in ALP-overexpressed tumor cells compared to the culture medium, accompanied by massive depletion of intracellular thiols, the major antioxidants in cells. The investigation of this ALP-activatable NIR PS in an in vivo PDT model resulted in complete suppression of HeLa tumors and full recovery of all tested mice. Encouragingly, even a single administration of this NIR PS was sufficient to completely suppress tumors in mice, demonstrating the high potential of this strategy in biomedical applications.

Self-fueling ferroptosis-inducing microreactors based on pH-responsive Lipiodol Pickering emulsions enable transarterial ferro-embolization therapy

Lipiodol chemotherapeutic emulsions remain one of the main choices for the treatment of unresectable hepatocellular carcinoma (HCC) via transarterial chemoembolization (TACE). However, the limited stability of Lipiodol chemotherapeutic emulsions would lead to rapid drug diffusion, which would reduce the therapeutic benefit and cause systemic toxicity of administrated chemotherapeutics. Therefore, the development of enhanced Lipiodol-based formulations is of great significance to enable effective and safe TACE treatment. Herein, a stable water-in-oil Lipiodol Pickering emulsion (LPE) stabilized by pH-dissociable calcium carbonate nanoparticles and hemin is prepared and utilized for efficient encapsulation of lipoxygenase (LOX). The obtained LOX-loaded CaCO3&hemin-stabilized LPE (LHCa-LPE) showing greatly improved emulsion stability could work as a pH-responsive and self-fueling microreactor to convert polyunsaturated fatty acids (PUFAs), a main component of Lipiodol, to cytotoxic lipid radicals through the cascading catalytic reaction driven by LOX and hemin, thus inducing ferroptosis of cancer cells. As a result, such LHCa-LPE upon transcatheter embolization can effectively suppress the progression of orthotopic N1S1 HCC in rats. This study highlights a concise strategy to prepare pH-responsive and stable LPE-based self-fueling microreactors, which could serve as bifunctional embolic and ferroptosis-inducing agents to enable proof-of-concept transarterial ferro-embolization therapy of HCC.

Potential molecular mechanisms of myrtenal against colon cancer: A systematic review

Colon cancer is a serious health problem across the globe with various dietary lifestyle modifications. It arises as an inflammation mediated crypts in the colon epithelial cells and undergoes uncontrolled cell division and proliferation. Bacterial enzymes contribute to a major outbreak in colon cancer development upon the release of toxic metabolites from the gut microflora. Pathogen associated molecular patterns and damage associated molecular patterns triggers the NLPR3 inflammasome pathways that releases pro-inflammatory cytokines to induce cancer of the colon. Contributing to this, specific chemokines and receptor complexes attribute to cellular proliferation and metastasis. Bacterial enzymes synergistically attack the colon mucosa and degenerate the cellular integrity causing lysosomal discharge. These factors further instigate the Tol like receptors (TLRs) and Nod like receptors (NLRs) to promote angiogenesis and supply nutrients for the cancer cells. Myrtenal, a monoterpene, is gaining more importance in recent times and it is being widely utilized against many diseases such as cancers, neurodegenerative diseases and diabetes. Based on the research data's, the reviews focus on the anticancer property of myrtenal by emphasizing its therapeutic properties which downregulate the inflammasome pathways and other signalling pathways. Combination therapy is gaining more importance as they can target every variant in the cellular stress condition. Clinical studies with compounds like myrtenal of the monoterpenes family is provided with positive results which might open an effective anticancer drug therapy. This review highlights myrtenal and its biological potency as a cost effective drug for prevention and treatment of colon cancer.

MOF-derived porous carbon nanozyme-based flexible electrochemical sensing system for in situ and real-time monitoring of H2O2 released from cells

A novel flexible electrochemical sensor based on porous carbon nanosheets (PCNSs) nanozyme has been constructed for in situ and real-time monitoring of H2O2 released by cells. The PCNSs are prepared with the integration of thermal transformation, thermal activation and sonochemical exfoliation by using zeolitic imidazolate frameworks as template. The PCNSs exhibit high electrical conductivity, electrochemical activity and peroxidase-like catalytic properties, which is beneficial to H2O2 assay. With the transfer printing method, the flexible electrochemical sensor is obtained, which has excellent performances for H2O2 electrochemical detecting with wide linear range from 1 μM to 20 mM and a low detection limit of 0.76 μM. Owing to the great biocompatibility, the flexible sensor guarantees the growth of living cells for 72 h and realizes in situ and real-time monitoring the release of H2O2 from HeLa cells. The strategy of porous nanozyme preparation and flexible sensor construction provided a promising way for in situ and real-time assay of small molecules in the cellular microenvironment.

Nanomedicine Combats Drug Resistance in Lung Cancer

Lung cancer is the second most prevalent cancer and the leading cause of cancer-related death worldwide. Surgery, chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy are currently available as treatment methods. However, drug resistance is a significant factor in the failure of lung cancer treatments. Novel therapeutics have been exploited to address complicated resistance mechanisms of lung cancer and the advancement of nanomedicine is extremely promising in terms of overcoming drug resistance. Nanomedicine equipped with multifunctional and tunable physiochemical properties in alignment with tumor genetic profiles can achieve precise, safe, and effective treatment while minimizing or eradicating drug resistance in cancer. Here, this work reviews the discovered resistance mechanisms for lung cancer chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy, and outlines novel strategies for the development of nanomedicine against drug resistance. This work focuses on engineering design, customized delivery, current challenges, and clinical translation of nanomedicine in the application of resistant lung cancer.

Recent advances in sonodynamic therapy strategies for pancreatic cancer

Pancreatic cancer, a prevalent malignancy of the digestive system, has a poor 5-year survival rate of around 10%. Although numerous minimally invasive alternative treatments, including photothermal therapy and photodynamic therapy, have shown effectiveness compared with traditional surgical procedures, radiotherapy, and chemotherapy. However, the application of these alternative treatments is constrained by their depth of penetration, making it challenging to treat pancreatic cancer situated deep within the tissue. Sonodynamic therapy (SDT) has emerged as a promising minimally invasive therapy method that is particularly potent against deep-seated tumors such as pancreatic cancer. However, the unique characteristics of pancreatic cancer, including a dense surrounding matrix, high reductivity, and a hypoxic tumor microenvironment, impede the efficient application of SDT. Thus, to guide the evolution of SDT for pancreatic cancer therapy, this review addresses these challenges, examines current strategies for effective SDT enhancement for pancreatic cancer, and investigates potential future advances to boost clinical applicability. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Tumor Microenvironment Heterogeneity, Potential Therapeutic Avenues, and Emerging Therapies

OBJECTIVE

This review describes the comprehensive portrait of tumor microenvironment (TME). Additionally, we provided a panoramic perspective on the transformation and functions of the diverse constituents in TME, and the underlying mechanisms of drug resistance, beginning with the immune cells and metabolic dynamics within TME. Lastly, we summarized the most auspicious potential therapeutic strategies.

RESULTS

TME is a unique realm crafted by malignant cells to withstand the onslaught of endogenous and exogenous therapies. Recent research has revealed many small-molecule immunotherapies exhibiting auspicious outcomes in preclinical investigations. Furthermore, some pro-immune mechanisms have emerged as a potential avenue. With the advent of nanosystems and precision targeting, targeted therapy has now transcended the "comfort zone" erected by cancer cells within TME.

CONCLUSION

The ceaseless metamorphosis of TME fosters the intransigent resilience and proliferation of tumors. However, existing therapies have yet to surmount the formidable obstacles posed by TME. Therefore, scientists should investigate potential avenues for therapeutic intervention and design innovative pharmacological and clinical technologies.

Synthesis of a Multifunctional Glyco-Block Copolymer through Reversible Addition-Fragmentation Chain Transfer Polymerization and Click Chemistry for Enzyme and Drug Loading into MDA-MB-231 Cells

Reversible addition-fragmentation chain transfer polymerization has been used in various applications such as preparing nanoparticles, stimulus-responsive polymers, and hydrogels. In this study, the combination of this polymerization method and Cu(I)-catalyzed azide-alkyne cycloaddition click chemistry was used to prepare the multifunctional glyco-diblock copolymer P(PEG-co-AM)-b-PF, which is composed of mannosides for cell targeting, poly(ethylene glycol) (PEG) for biocompatibility, and aryl-aldehyde moieties for enzyme immobilization. The alkyne group in the polymer structure enables the alternation for other azide-conjugated monomers. The stepwise synthesis of the polymers was fully characterized. P(PEG-co-AM)-b-PF was self-assembled into polymeric nanoparticles (BDOX-GOx@NPs) for glucose oxidase immobilization through Schiff base formation and for encapsulating the prodrug of arylboronate-linked doxorubicin (BA-DOX) under optimal conditions. Glucose oxidase in BDOX-GOx@NPs catalyzes glucose oxidation to produce gluconic acid and H2O2, which cause oxidative stress. Glucose oxidase also consumes glucose, causing starvation in cancer cells. The produced H2O2 can selectively activate the anticancer prodrug BA-DOX for chemotherapy. In vitro data indicate that GOx and the prodrug BA-DOX present inside BDOX-GOx@NPs exhibit higher stability than free glucose oxidase with a favorable active DOX release profile. MDA-MB-231 cells, which express mannose receptors, were used to establish a model in this study. The bioactivity of the nanoplatform in the two- and three-dimensional models of MDA-MB-231 cancer cells was investigated to ascertain its antitumor efficacy.

Diselenium-linked dimeric prodrug nanomedicine breaking the intracellular redox balance for triple-negative breast cancer targeted therapy

Triple-negative breast cancer (TNBC) has been regarded as the strongest malignancy in cases of breast cancer with a poor prognosis. The development of effective treatment strategies for TNBC has always been an urgent and unmet need. The intracellular redox balance is essential for maintaining TNBC cell malignancy. Disrupting intracellular redox balance by enlarging reactive oxygen species (ROS) generation and facilitating glutathione (GSH) depletion to amplify intracellular oxidative stress may be an alternative strategy to eliminate TNBC cells. However, inducing ROS generation and GSH depletion concurrently may be challenging. Herein, a diselenium linked-dimeric prodrug nanomedicine FA-SeSe-NPs was developed to break the intracellular redox homeostasis for TNBC targeted therapy. The dimeric prodrug was synthesized by conjugating two cucurbitacin B (CuB) molecules via one diselenium bond, which was subsequently assembled with FA-PEG-DSPE to form the final nanomedicine FA-SeSe-NPs. Using the active targeting potential of folic acid (FA), FA-SeSe-NPs could accumulate in tumor tissue with elevated levels and then be specifically internalized by cancer cells. In the high ROS and GSH conditions of TNBC cells, the diselenium bond can specifically respond to ROS to produce selenium free radicals to increase ROS and react with GSH to generate S-Se bond to deplete GSH. The released CuB further induced ROS production in TNBC cells. The diselenium bond and CuB functioned synergistically to amplify oxidative stress to kill the TNBC cells. Here, we provide a promising strategy to disrupt the intracellular redox balance of cancer cells for effective TNBC therapy.

Smart chemistry for traceless release of anticancer therapeutics

In the design of delivery strategies for anticancer therapeutics, the controlled release of intact cargo at the destined tumor and metastasis locations is of particular importance. To this end, stimuli-responsive chemical linkers have been extensively investigated owing to their ability to respond to tumor-specific physiological stimuli, such as lowered pH, altered redox conditions, increased radical oxygen species and pathological enzymatic activities. To prevent premature action and off-target effects, anticancer therapeutics are chemically modified to be transiently inactivated, a strategy known as prodrug development. Prodrugs are reactivated upon stimuli-dependent release at the sites of interest. As most drugs and therapeutic proteins have the optimal activity when released from carriers in their native and original forms, traceless release mechanisms are increasingly investigated. In this review, we summarize the chemical toolkit for developing innovative traceless prodrug strategies for stimuli-responsive drug delivery and discuss the applications of these chemical modifications in anticancer treatment including cancer immunotherapy.

Supramolecular Nano-Assembly of Caffeate-Strengthened Phenylboronic Ester with Multistep ROS Scavenging Ability for Targeted Therapy of Acute Kidney Injury

Acute kidney injury (AKI) is a life-threatening complication with a considerable occurrence among patients. AKI is typically accompanied by an elevation in reactive oxidative species (ROS) in renal tissues, which is the main contributor to kidney damage. Herein, a supramolecular nano-assembly (Ser-HPEC) containing an ethyl caffeate-strengthened phenylboronic ester with ROS-triggered antioxidative ability is proposed for AKI-targeted therapy. Nano-assemblies can rapidly accumulate in the ischemia-reperfusion-injured kidney via kidney injury molecule-1 (Kim-1)-mediated homing ability of l-serine. By consuming pathological levels of ROS, two different antioxidants, ethyl caffeate and 4-hydroxybenzyl alcohol, are spontaneously released from a single module to relieve oxidative stress and diminish acute inflammation in injured renal tissue. The multistep ROS scavenging strategy combined with a precise targeting capability endows the aforementioned nano-assembly with effectiveness in preserving the integrity and functions of the injured kidney, providing new inspiration for the treatment of inflammatory diseases, including AKI.

ROS/pH dual-sensitive emodin-chlorambucil co-loaded micelles enhance anti-tumor effect through combining oxidative damage and chemotherapy

The high level of reactive oxygen species (ROS) at the tumor site has been widely used in the tumor targeted delivery. However, the ROS stimulus-responsive vector itself is also a ROS consumer, and the consumption of endogenous ROS may not be sufficient to maintain sustained drug release. In this study, we designed and synthesized ROS/pH dual-sensitive polymer micelles for the co-delivery of emodin (EMD) and chlorambucil (CLB). The release of quinone methides (QM) can consume glutathione (GSH), on the one hand, it can enhance the chemotoxicity of phenylbutyrate nitrogen mustard, on the other hand, emodin can induce oxidative damage of tumor cells and maintain the sustained targeted release of drugs.

Targeted echogenic and anti-inflammatory polymeric prodrug nanoparticles for the management of renal ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury is an inevitable pathological event occurring when blood is resupplied to the tissues after a period of ischemia. One of major causes of IR injury is the overproduction of reactive oxygen species (ROS) including hydrogen peroxide (H2O2), which mediates the expression of various inflammatory cytokines to exacerbate tissue damages. The overproduced H2O2 could therefore serve as a diagnostic and therapeutic biomarker of IR injury. In this study, poly(boronated methacrylate) (pBMA) nanoparticles were developed as nanotheranostic agents for renal IR injury, which not only generate CO2 bubbles to enhance the ultrasound contrast but also provide potent preventive effects in a H2O2-triggered manner. The surface of pBMA nanoparticles was decorated with taurodeoxycholic acid (TUDCA) that binds P-selectin overexpressed in inflamed tissues. In the mouse model of renal IR injury, TUDCA-coated pBMA (T-pBMA) nanoparticles preferentially accumulated in the injured kidney and markedly enhanced the ultrasound contrast. T-pBMA nanoparticles also effectively prevented renal IR injury by scavenging H2O2 and suppressing the expression of inflammatory cytokines. Treatment progress of IR injury could be also monitored by echogenic T-pBMA nanoparticles. Given their targeting ability, excellent H2O2-responsiveness, anti-inflammatory activity and H2O2-triggered echogenicity, T-pBMA nanoparticles have excellent translational potential for the management of various H2O2-related diseases including IR injury.

Reactive Oxygen Species-Responsive Polymeric Prodrug Nanoparticles for Selective and Effective Treatment of Inflammatory Diseases

It is challenging to manage inflammatory diseases using traditional anti-inflammatory drugs due to their limited efficacy and systemic side effects, which are a result of their lack of selectivity, poor stability, and low solubility. Herein, it reports the development of a novel nanoparticle system, called ROS-CA-NPs, which is formed using polymer-cinnamaldehyde (CA) conjugates and is responsive to reactive oxygen species (ROS). ROS-CA-NPs exhibit excellent drug stability, tissue selectivity, and controlled drug release upon oxidative stress activation. Using mouse models of chronic rheumatoid arthritis and acute ulcerative colitis, this study demonstrates that the systemic administration of ROS-CA-NPs results in their accumulation at inflamed lesions and leads to greater therapeutic efficacy compared to traditional drugs. Furthermore, ROS-CA-NPs present excellent biocompatibility. The findings suggest that ROS-CA-NPs have the potential to be developed as safe and effective nanotherapeutic agents for a broad range of inflammatory diseases.

Polyphenolic Carbon Quantum Dots with Intrinsic Reactive Oxygen Species Amplification for Two-Photon Bioimaging and In Vivo Tumor Therapy

Recent studies indicate that mitochondrial dysfunctions and DNA damage have a critical influence on cell survival, which is considered one of the therapeutic targets for cancer therapy. In this study, we demonstrated a comparative study of the effect of polyphenolic carbon quantum dots (CQDs) on in vitro and in vivo antitumor efficacy. Dual emissive (green and yellow) shape specific polyphenolic CQDs (G-CQDs and Y-CQDs) were synthesized from easily available nontoxic precursors (phloroglucinol), and the antitumor property of the as-synthesized probe was investigated as compared to round-shaped blue emissive CQDs (B-CQDs) derived from well-reported precursor citric acid and urea. The B-CQDs had a nuclei-targeting property, and G-CQDs and Y-CQDs had mitochondria-targeting properties. We have found that the polyphenol containing CQDs (at a dose of 100 μg mL-1) specifically attack mitochondria by excess accumulation, altering the metabolism, inhibiting branching pattern, imbalanced Bax/Bcl-2 homeostasis, and ultimately generating oxidative stress levels, leading to oxidative stress-induced cell death in cancer cells in vitro. We show that G-CQDs are the main cause of oxidative stress in cancer cells because of their ability to produce sufficient •OH- and 1O2 radicals, evidenced by electron paramagnetic resonance spectroscopy and a terephthalic acid test. Moreover, the near-infrared absorption properties of the CQDs were exhibited in two-photon (TP) emission, which was utilized for TP cellular imaging of cancer cells without photobleaching. The in vivo antitumor test further discloses that intratumoral injection of G-CQDs can significantly augment the treatment efficacy of subcutaneous tumors without any adverse effects on BalB/c nude mice. We believe that shape-specific polyphenolic CQD-based nanotheranostic agents have a potential role in tumor therapy, thus proving an insight on treatment of malignant cancers.

Acid-sensitive stable polymeric micelle-based oxidative stress nanoamplifier as immunostimulating anticancer nanomedicine

Oxidative stress amplifying compounds could elicit selective killing of cancer cells with minimal toxicity to normal cells and also induce immunogenic cell death (ICD). However, compared to conventional anticancer drugs, oxidative stress amplifying compounds have inferior therapeutic efficacy. It can be postulated that the anticancer therapeutic efficacy and immunostimulating activity of oxidative stress amplifying hybrid prodrug (OSamp) could be fully maximized by employing ultrastable polymeric micelles as drug carriers. In this work, we developed tumour-targeted oxidative stress nanoamplifiers, composed of OSamp, amphiphilic poly(ethylene glycol) methyl ether-block-poly(cyclohexyloxy ethyl glycidyl ether)s (mPEG-PCHGE) and a lipopeptide containing Arg-Gly-Asp (RGD). Tumour targeted OSamp-loaded mPEG-PCHGE (T-POS) micelles exhibited excellent colloidal stability and significant cytotoxicity to cancer cells with the expression of DAMPs (damage-associated molecular patterns). In the syngeneic mouse tumour model, T-POS micelles induced significant apoptotic cell death to inhibit tumour growth without noticeable body weight changes. T-POS micelles also induced ICD and activated adaptive immune responses by increasing the populations of cytotoxic CD4+ and CD8+ T cells. Therefore, these results suggest that T-POS micelles hold great translational potential as immunostimulating anticancer nanomedicine.

A tumor cell exosome-mimicking multifunctional nanozyme for targeted breast cancer radiotherapy

Radiotherapy (RT) has been extensively used for the treatment of breast cancer. However, the efficacy of RT is reduced by the high content of reducing species within cells (such as glutathione (GSH)). In addition, high-dose radiotherapy is often accompanied by serious side effects. In an attempt to resolve these issues, a tumor cell exosome-mimicking multifunctional nanozyme system (CuPy-Au@EM) was developed as a radiosensitizer, which consists of an internal AuNP-embedded CuPy nanozyme core and an external tumor cell exosome membrane. The exosome membrane protein on the surface of CuPy-Au@EM leads to the accurate localization of nano-materials in the tumor site; simultaneously, the level of H2O2 will be enhanced because of the GOx-like activity of AuNPs. Then CuPy-Au@EM would continue to trigger a rapid decline in cellular GSH content and the production of a large number of hydroxyl radicals (˙OH) through its glutathione peroxidase (GPx) and peroxidase (POD) activities allows for the extension of the radiotherapeutic cascade. Studies conducted in vivo and in vitro demonstrated that the combination of CuPy-Au@EM and moderate dose RT (4 Gy) can significantly reduce tumor proliferation. These findings indicated that CuPy-Au@EM nanospheres could be plausibly developed into promising radio-sensitizers on tumors.

Glutathione-sensitive mesoporous nanoparticles loaded with cinnamaldehyde for chemodynamic and immunological therapy of cancer

Chemodynamic therapy as a novel type of chemotherapy can damage the DNA structures and induce cell apoptosis and immunogenic cell death (ICD) through generating reactive oxygen species (ROS) to aggravate oxidative stress. Nonetheless, as an intrinsic antioxidative response of tumor cells, the expression of glutathione (GSH) can be upregulated to maintain the cellular redox balance and protect the tumor cells from ROS-mediated damage. In this context, it is feasible to simultaneously boost ROS generation and GSH depletion in tumor cells; however, the precise delivery and release of GSH scavengers at specific subcellular sites is of great importance. Herein, we propose a GSH-responsive mesoporous organosilica nanoparticle (MON)-based nanomedicine MON-CA-TPP@HA through sequentially covalently attaching triphenylphosphine (TPP) and electrostatically coating hyaluronic acid (HA) onto the surface of cinnamaldehyde (CA)-loaded MONs, known as MON-CA-TPP@HA, which has been demonstrated to be an extremely effective therapeutic strategy for cancer treatment through inducing ICD and apoptosis of breast cancer cells. Systematic in vitro experimental results clearly revealed that the nanomedicine can actively target the tumor cells with the help of HA, subsequently enter the tumor cells, and precisely bind with the mitochondria through TPP residues. Upon cleavaging the disulfide bond in the MONs triggered by over-expressed GSH within tumors, the CA molecules can be released inducing the excessive ROS in situ surrounding the mitochondria to activate oxidative stress to induce apoptosis and ICD of breast cancer cells. The results of the in vivo experiments confirm that the MON-CA-TPP@HA nanomedicine can effectively promote dendritic cell (DC) maturation and CD 8+ T cell activation and regulate the ratio of M1/M2 macrophages, which improve tumor immunosuppressive microenvironment. It is thus believed that the current nanomedicine has paved a new way for future cancer therapy.

Mechanism underlying the effect of MnO2 nanosheets for A549 cell chemodynamic therapy

MnO2 nanosheets (MnO2NSs) were synthesized by one-step method, and MnO2NSs were applied to A549 cell chemodynamic Therapy (CDT). The cytotoxicity, redox ability, and reactive oxygen species production of MnO2NSs have been investigated, and differences in cell metabolism during CDT were determined using liquid chromatography-mass spectrometry (LC-MS/MS). In addition, the metabolites of A549 lung cancer cells affected by MnO2NSs treatment are identified; metabolite differences were identified by PCA, PLS-DA, orthogonal PLS-DA, and other methods; and these differences were analyzed using non-targeted metabolomics. We found that A549 cells which were treated by MnO2NSs have 17 different metabolites and 9 metabolic pathways that varied markedly. Owing to their unique composition, structure, and physicochemical properties, MnO2NSs and their composites have become a favored type of nanomaterial used for CDT in cancer therapy. This work provides insights into the mechanism underlying the effects of MnO2NSs on the tumor microenvironment of A549 lung cancer cells, effectively making up for the deficiency of the study on cellular mechanism of CDT-induced apoptosis of cancer cells. It could aid the development of cancer CDT treatment strategies and help improve the use of nanomaterials in the clinical field.

Enhanced Transcutaneous Chemodynamic Therapy for Melanoma Treatment through Cascaded Fenton-like Reactions and Nitric Oxide Delivery

Chemodynamic therapy (CDT) has emerged as a promising strategy for cancer treatment. However, its effectiveness has been hindered by insufficient hydrogen peroxide (H2O2) and high reductive glutathione (GSH) within tumors, which are the two main reasons for the inefficiency of Fenton/Fenton-like reaction-based CDT. Herein, we present a H2O2 boost-GSH depletion strategy for enhanced CDT to fight against melanoma through a microneedle (MN)-based transcutaneous delivery method. The MN system is composed of dissolvable polyvinylpyrrolidone integrated with stimuli-responsive prodrugs. Under an intracellular acidic environment, the smart release of H2O2 boosting components is triggered, subsequently initiating nitric oxide (NO) release and enhancing the Fenton-like reaction in a cascade manner. The generation of hydroxyl radicals (•OH), along with the depletion of GSH by NO, amplifies the oxidative stress within tumor cells, promoting apoptosis and ferroptosis. The antitumor efficacy of the MN patch is validated in an A375 mouse melanoma model. This "H2O2 boost-GSH depletion-Fenton killing" strategy expands the options for superficial tumor treatment through MN-mediated enhanced CDT.

Self-driven nanoprodrug platform with enhanced ferroptosis for synergistic photothermal-IDO immunotherapy

Insufficient immune stimulation and stubborn immune resistance are the critical factors limiting tumor immunotherapy. Here, we report a multifunctional nanoprodrug platform with self-driven indoximod (IND) release and oxidative stress amplification. The aim is to awaken immune responses and block the indoleamine 2,3-dioxygenase (IDO) pathway through a combination of ferroptosis, photothermal therapy, and immunotherapy. This nanosystem improved the delivery efficiency of IND due to click chemistry linked ROS responsive prodrug and self-driven drug release. Meanwhile, the tactic of simultaneously increasing ROS and eliminating GSH amplified oxidative stress and strengthened ferroptosis, which further enhanced immunogenicity along with polydopamine-based photothermal therapy. IDO immunization combined with ferroptosis as well as photothermal therapy not only stimulated immune response, but also reversed immune suppression with enhanced immune memory. Therefore, primary tumor, distant tumor, and cancer metastasis were inhibited. This study provides a perspective on immunotherapeutics for cancer treatment.

Tumor Therapy Strategies Based on Microenvironment-Specific Responsive Nanomaterials

The tumor microenvironment (TME) is a complex and variable region characterized by hypoxia, low pH, high redox status, overexpression of enzymes, and high-adenosine triphosphate concentrations. In recent years, with the continuous in-depth study of nanomaterials, more and more TME-specific response nanomaterials are used for tumor treatment. However, the complexity of the TME causes different types of responses with various strategies and mechanisms of action. Aiming to systematically demonstrate the recent advances in research on TME-responsive nanomaterials, this work summarizes the characteristics of TME and outlines the strategies of different TME responses. Representative reaction types are illustrated and their merits and demerits are analyzed. Finally, forward-looking views on TME-response strategies for nanomaterials are presented. It is envisaged that such emerging strategies for the treatment of cancer are expected to exhibit dramatic trans-clinical capabilities, demonstrating the extensive potential for the diagnosis and therapy of cancer.