Engineering nanomedicine for glutathione depletion-augmented cancer therapy

Glutathione-depleting polyprodrug nanoparticle for enhanced photodynamic therapy and cascaded locoregional chemotherapy

Nanomedicines that combine reactive oxygen species (ROS)-responsive polyprodrug and photodynamic therapy have shown great potential for improving treatment efficacy. However, the consumption of ROS by overexpressed glutathione in tumor cells is a major obstacle for achieving effective ROS amplification and prodrug activation. Herein, we report a polyprodrug-based nanoparticle that can realize ROS amplification and cascaded drug release. The nanoparticle can respond to the high level of hydrogen peroxide in tumor microenvironment, achieving self-destruction and release of quinone methide. The quinone methide depletes intracellular glutathione and thus decreases the antioxidant capacity of cancer cells. Under laser irradiation, a large amount of ROS will be generated to induce cell damage and prodrug activation. Therefore, the glutathione-depleting polyprodrug nanoparticles can efficiently inhibit tumor growth by enhanced photodynamic therapy and cascaded locoregional chemotherapy.

DNA-based FeCuAg nanoclusters with peroxidase-like and GSH depletion activities for toxicity of in vitro cancer cells

Developing the efficient nanozymes for reactive oxygen species (ROS)-mediated highly potent tumor catalytic therapy has become a great challenge. In this study, we prepared the DNA-Fe, -FeAg, and -FeCuAg nanocluster (NCs) using the G-/C-rich single-stranded DNA (ssDNA) templates. The steady-state kinetic and the catalytic performances and mechanisms of DNA-metal NCs were first systematically investigated. The results indicated that c-kit-TBA-Fe, c-kit-TBA-FeAg, and c-kit-TBA-FeCuAg NCs exhibited the high peroxidase-like activity. All of three types of NCs presented the higher affinity to the substrate TMB and better storage stability at 4 °C than horseradish peroxidase (HRP). Moreover, c-kit-TBA-FeAg and c-kit-TBA-FeCuAg NCs presented the 6.7- and 4.7-fold stronger affinity to TMB than c-kit-TBA-Fe, respectively. However, the maximum reaction rate (Vmax) of c-kit-TBA-FeCuAg NCs with H2O2 was the largest, which promoted the generation of much more •OH in the reaction system. More importantly, c-kit-TBA-FeCuAg NCs were able to deplete largely the intracellular GSH and thus generate lots of endogenous ROS in HeLa cells, thereby exhibiting the significant and specific in vitro cancer cells toxicity. Therefore, c-kit-TBA-FeCuAg NCs, with peroxidase-like activity and glutathione (GSH) consumption ability, hold the ROS-based promising therapeutic effects for cancer.

Targeting nanoplatform synergistic glutathione depletion-enhanced chemodynamic, microwave dynamic, and selective-microwave thermal to treat lung cancer bone metastasis

Once bone metastasis occurs in lung cancer, the efficiency of treatment can be greatly reduced. Current mainstream treatments are focused on inhibiting cancer cell growth and preventing bone destruction. Microwave ablation (MWA) has been used to treat bone tumors. However, MWA may damage the surrounding normal tissues. Therefore, it could be beneficial to develop a nanocarrier combined with microwave to treat bone metastasis. Herein, a microwave-responsive nanoplatform (MgFe2O4@ZOL) was constructed. MgFe2O4@ZOL NPs release the cargos of Fe3+, Mg2+ and zoledronic acid (ZOL) in the acidic tumor microenvironment (TME). Fe3+ can deplete intracellular glutathione (GSH) and catalyze H2O2 to generate •OH, resulting in chemodynamic therapy (CDT). In addition, the microwave can significantly enhance the production of reactive oxygen species (ROS), thereby enabling the effective implementation of microwave dynamic therapy (MDT). Moreover, Mg2+ and ZOL promote osteoblast differentiation. In addition, MgFe2O4@ZOL NPs could target and selectively heat tumor tissue and enhance the effect of microwave thermal therapy (MTT). Both in vitro and in vivo experiments revealed that synergistic targeting, GSH depletion-enhanced CDT, MDT, and selective MTT exhibited significant antitumor efficacy and bone repair. This multimodal combination therapy provides a promising strategy for the treatment of bone metastasis in lung cancer patients.

The elevated expression of serum glutathione reductase in hepatocellular carcinoma and its role in assessing the therapeutic efficacy and prognosis of transarterial chemoembolization

BACKGROUND

Currently, there is a scarcity of reliable biomarkers that can accurately forecast the outcome and prognosis of transarterial chemoembolization (TACE). In this study, we assessed the diagnostic efficacy of serum glutathione reductase (GR) as a biomarker for hepatocellular carcinoma (HCC) and its practicality in predicting TACE treatment response.

METHODS

The baseline positive rate and level of serum GR were analyzed and compared between HCC group and control group. Serum GR levels were assessed at three specific time points in 181 patients with unresectable HCC who underwent TACE (HCC-TACE). The correlation between serum GR levels and clinical pathological factors, tumor reactivity, and prognosis was investigated. The modified Response Evaluation Criteria in Solid Tumors (mRECIST) was utilized for assessing the treatment response to TACE. A nomogram for predicting the response to TACE treatment efficacy was developed.

RESULTS

Serum GR demonstrated superior diagnostic performance in HCC patients. The baseline levels of serum GR were associated with the patient's age, tumor size, BCLC staging, and tumor thrombi of the portal vein (TTPV) (p < 0.05). Elevated baseline levels of serum GR were also identified as independent prognostic factors for predicting lower overall survival (OS) and shorter time to radiological progression (TTP) (p < 0.001). Moreover, it is worth noting that non-responders group exhibited a substantial increase in median GR level in the fourth week following TACE treatment (p < 0.0001), whereas the median GR level of responders group did not display a significant augmentation (p > 0.05). Lastly, the changes in serum GRt1-t3 were negatively correlated with TTP (p < 0.001). The nomogram developed to predict the risk of mRECIST responsiveness in patients with HCC-TACE demonstrated excellent discriminatory ability.

CONCLUSION

Serum GR can serve as a valuable biomarker for the diagnosis of HCC and for predicting the therapeutic efficacy and prognosis of TACE treatment.

Preparation of hollow double-layer Pt@CeO2 nanospheres as oxidase mimetics for the colorimetric-fluorescent-SERS triple-mode detection of glutathione in serum

Glutathione (GSH) is an essential antioxidant in the human body, but its detection is difficult due to the interference of complex components in serum. Herein, hollow double-layer Pt@CeO2 nanospheres were developed as oxidase mimetics, and the light-assisted oxidase mimetics effects were found. The oxidase activity was enhanced significantly by utilizing the synergistic effect of Schottky junction and the localized surface plasmon resonance (LSPR) of Pt under UV light. A novel GSH colorimetric-fluorescent-SERS sensing platform was established, with the sensing performance notably boosted by using the light-assisted oxidase mimetics effects. This platform boasts an exceptionally low detection limit (LOD) of 0.084 μM, while the detection time was shortened from 10 min to just 2 min. The anti-interference detection with high recovery rate (96.84%-107.4 %) in real serum made it be promising for practical application.

Maleimide functionalized polycaprolactone micelles for glutathione quenching and doxorubicin delivery

High glutathione production is known to be one of the defense mechanisms by which many cancer cells survive elevated oxidative stress. By explicitly targeting glutathione in these cancer cells and diminishing its levels, oxidative stress can be intensified, ultimately triggering apoptosis or programmed cell death. Herein, we developed a novel approach by creating maleimide-functionalized polycaprolactone polymers, specifically using 2,3-diiodomaleimide functionality to reduce the level of glutathione in cancer cells. Polycaprolactone was chosen to conjugate the 2,3-diiodomaleimide functionality due to its biodegradable and biocompatible properties. The amphiphilic block copolymer was synthesized using PEG as a macroinitiator to make corresponding polymeric micelles. The resulting 2,3-diiodomaleimide-conjugated polycaprolactone micelles effectively quenched glutathione, even at low concentrations (0.01 mg mL-1). Furthermore, we loaded these micelles with the anticancer drug doxorubicin (DOX), which exhibited pH-dependent drug release. We obtained a loading capacity (LC) of 3.5% for the micelles, one of the highest LC reported among functional PCL-based micelles. Moreover, the enhanced LC doesn't affect their release profile. Cytotoxicity experiments demonstrated that empty and DOX-loaded micelles inhibited cancer cell growth, with the DOX-loaded micelles displaying the highest cytotoxicity. The ability of the polymer to quench intracellular GSH was also confirmed. This approach of attaching maleimide to polycaprolactone polymers shows promise in depleting elevated glutathione levels in cancer cells, potentially improving cancer treatment efficacy.

"Four-in-One" Nanozyme for Amplified Catalytic-Photothermal Therapy

The cancer therapeutic efficacy of the peroxidase (POD)-mimicking nanozyme-based monotherapy is significantly hindered due to insufficient intratumoral hydrogen peroxide (H2O2) and glutathione (GSH) consumption effect on reactive oxygen species (ROS). In this study, we present the development of poly(o-phenylenediamine)@gold nanoparticles (AuNPs) (PoPD@Au) nanocomposites for multifunctional catalytic-photothermal therapy. These nanocomposites exhibit triple distinct nanozymatic activities, i.e., POD-like activity that catalyzes H2O2 to ROS, glucose oxidase (GOx)-like activity that supplements endogenous H2O2, and GSH depleting activity that decreases the ROS consumption efficiency. This open source and reduce expenditure strategy for ROS generation allows for the amplification of tumor oxidative stress, thereby enhancing anti-tumor efficiency. Additionally, the PoPD@Au nanocomposites demonstrate outstanding photothermal conversion efficiency, contributing to the synergistic effect between PoPD and AuNPs. Moreover, we reveal the improved photothermal performance of PoPD@Au triggered by the tumor microenvironment pH, which provides additional benefits for targeted catalytic-photothermal therapy. This "four-in-one" design of PoPD@Au enables efficient anti-tumor effects both in vitro and in vivo, making it a universal strategy for engineering catalytic-photothermal therapeutic nanoagents.

Biomimetic copper-doped polypyrrole nanoparticles induce glutamine metabolism inhibition to enhance breast cancer cuproptosis and immunotherapy

Cuproptosis, a newly discovered mechanism of inducing tumor cell death, primarily relies on the intracellular accumulation of copper ions. The utilization of Cu-based nanomaterials to induce cuproptosis holds promising prospects in future biomedical applications. However, the presence of high levels of glutathione (GSH) within tumor cells hinders the efficacy of cuproptosis. In this study, we have developed a BPTES-loaded biomimetic Cu-doped polypyrrole nanoparticles (CuP) nanosystem (PCB) for enhanced cuproptosis and immune modulation. PCB comprises an internal BPTES and CuP core and an external platelet membrane (PM) that facilitates active targeting to tumor sites following intravenous administration. Subsequently, PCB effectively suppresses glutaminase (GLS1) activity, thereby reducing GSH content. Moreover, CuP catalyze intracellular H2O2, amplifying oxidative stress while simultaneously inducing dihydrolipoyl transacetylase (DLAT) oligomerization through released Cu2+, resulting in cuproptosis. PCB not only inhibits primary tumors but also exhibits inhibitory effects on abscopal tumors. This work represents the first instance where GLS inhibition has been employed to enhance cuproptosis and immunotherapy. It also provides valuable insights into further investigations on cuproptosis.

Hyaluronic acid-based multifunctional nanoplatform for glucose deprivation-enhanced chemodynamic/photothermal synergistic cancer therapy

We present a hyaluronic acid (HA)-based nanoplatform (CMGH) integrating starvation therapy (ST), chemodynamic therapy (CDT), and photothermal therapy (PTT) for targeted cancer treatment. CMGH fabrication involved the encapsulation of glucose oxidase (GOx) within a copper-based metal-organic framework (CM) followed by surface modification with HA. CMGH exerts its antitumor effects by catalyzing glucose depletion at tumor sites, leading to tumor cell starvation and the concomitant generation of glucuronic acid and H2O2. The decreased pH and elevated H2O2 promote the Fenton-like reaction of Cu ions, leading to hydroxyl radical production. HA modification enables targeted accumulation of CMGH at tumor sites via the CD44 receptor. Under near-infrared light irradiation, CM exhibits photothermal conversion capability, enhancing the antitumor effects of CMGH. In vitro and in vivo studies demonstrate the effective inhibition of tumor growth by CMGH. This study highlights the potential of CMGH as a targeted cancer therapeutic platform.

Manganese-induced Photothermal-Ferroptosis for synergistic tumor therapy

Ferroptosis-related tumor therapy based on nanomedicines has recently gained significant attention. However, the therapeutic performance is still hindered by the tumor's physical barriers such as the fibrotic tumor matrix and elevated interstitial fluid pressure, as well as chemical barriers like glutathione (GSH) overabundance. These physicochemical barriers impede the bioavailability of nanomedicines and compromise the therapeutic efficacy of lipid reactive oxygen species (ROS). Thus, this study pioneers a manganese-mediated overcoming of physicochemical barriers in the tumor microenvironment using organosilica-based nanomedicine (MMONs), which bolsters the synergy of photothermal-ferroptosis treatment. The MMONs display commendable proficiency in overcoming tumor physical barriers, due to their MnO2-mediated shape-morphing and softness-transformation ability, which facilitates augmented cellular internalization, enhanced tumor accumulation, and superior drug penetration. Also, the MMONs possess excellent capability in chemical barrier overcoming, including MnO2-mediated dual GSH clearance and enhanced ROS generation, which facilitates ferroptosis and heat shock protein inhibition. Notably, the resulting integration of physical and chemical barrier overcoming leads to amplified photothermal-ferroptosis synergistic tumor therapy both in vitro and in vivo. Accordingly, the comparative proteomic analysis has identified promoted ferroptosis with a transient inhibitory response observed in the mitochondria. This research aims to improve treatment strategies to better fight the complex defenses of tumors.

Rapid Glutathione Analysis with SERS Microneedles for Deep Glioblastoma Tissue Differentiation

Rapid tissue differentiation at the molecular level is a prerequisite for precise surgical resection, which is of special value for the treatment of malignant tumors, such as glioblastoma (GBM). Herein, a SERS-active microneedle is prepared by modifying glutathione (GSH)-responsive molecules, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), on the surface of Au@Ag substrates for the distinction of different GBM tissues. Since the Raman signals on the surface of the DTNB@Au@Ag microneedle can be collected by both portable and benchtop Raman spectrometers, the distribution of GSH in different tissues at centimeter scale can be displayed through Raman spectroscopy and Raman imaging, and the entire analysis process can be accomplished within 12 min. Accordingly, in vivo brain tissues of orthotopic GBM xenograft mice and ex vivo tissues of GBM patients are accurately differentiated with the microneedle, and the results are well consistent with tissue staining and postoperative pathological reports. In addition, the outline of tumor, peritumoral, and normal tissues can be indicated by the DTNB@Au@Ag microneedle for at least 56 days. Considering that the tumor tissues are quickly discriminated at the molecular level without the restriction of depth, the DTNB@Au@Ag microneedle is promising to be a powerful intraoperative diagnostic tool for surgery navigation.

Super-assembled periodic mesoporous organosilica membranes with hierarchical channels for efficient glutathione sensing

Bioinspired nanochannel-based sensors have elicited significant interest because of their excellent sensing performance, and robust mechanical and tunable chemical properties. However, the existing designs face limitations due to material constraints, which hamper broader application possibilities. Herein, a heteromembrane system composed of a periodic mesoporous organosilica (PMO) layer with three-dimensional (3D) network nanochannels is constructed for glutathione (GSH) detection. The unique hierarchical pore architecture provides a large surface area, abundant reaction sites and plentiful interconnected pathways for rapid ionic transport, contributing to efficient and sensitive detection. Moreover, the thioether groups in nanochannels can be selectively cleaved by GSH to generate hydrophilic thiol groups. Benefiting from the increased hydrophilic surface, the proposed sensor achieves efficient GSH detection with a detection limit of 1.2 μM by monitoring the transmembrane ionic current and shows good recovery ranges in fetal bovine serum sample detection. This work paves an avenue for designing and fabricating nanofluidic sensing systems for practical and biosensing applications.

Glutathione-Sensitive Photosensitizer-Drug Conjugates Target the Mitochondria to Overcome Multi-Drug Resistance in Cancer

Multi-drug resistance (MDR) is a major cause of cancer therapy failure. Photodynamic therapy (PDT) is a promising modality that can circumvent MDR and synergize with chemotherapies, based on the generation of reactive oxygen species (ROS) by photosensitizers. However, overproduction of glutathione (GSH) by cancer cells scavenges ROS and restricts the efficacy of PDT. Additionally, side effects on normal tissues are unavoidable after PDT treatment. Here, to develop organic systems that deliver effective anticancer PDT and chemotherapy simultaneously with very little side effects, three GSH-sensitive photosensitizer-drug conjugates (CyR-SS-L) are designed and synthesized. CyR-SS-L localized in the mitochondria then is cleaved into CyR-SG and SG-L parts by reacting with and consuming high levels of intracellular GSH. Notably, CyR-SG generates high levels of ROS in tumor cells instead of normal cells and be exploited for PDT and the SG-L part is used for chemotherapy. CyR-SS-L inhibits better MDR cancer tumor inhibitory activity than indocyanine green, a photosensitizer (PS) used for PDT in clinical applications. The results appear to be the first to show that CyR-SS-L may be used as an alternative PDT agent to be more effective against MDR cancers without obvious damaging normal cells by the combination of PDT, GSH depletion, and chemotherapy.

Synthesis of a catalytic nanomaterial from polypyrrole and a pro-apoptotic peptide to target mitochondria for multimodal cancer therapy

Development of biocompatible nanomaterials with mitochondria-targeting and multimodal therapeutic activities is important for cancer treatment. Herein, we designed and synthesized a multifunctional pyrrole-based nanomaterial with photothermal effects and mitochondria-targeting properties from polypyrrole and the pro-apoptotic peptide KLA. Different from traditional strategies for the preparation of PPy nanoparticles, we innovatively used the KLA peptide as the template and CuCl2 as the catalyst to trigger the oxidative polymerization of pyrrole for PPy-KLA-Cu nanoparticle formation. Besides, due to the presence of mixed-valence Cu(I)/Cu(II) states, PPy-KLA-Cu nanoparticles also exhibited multienzyme-like activities, such as peroxidase, ascorbate oxidase and glutathione peroxidase activities, which can be exploited to elevate the intracellular ROS level and simultaneously consume GSH in cancer cells. More importantly, the heat generated by PPy-KLA-Cu nanoparticles from NIR irradiation could enhance the nanozymatic activities for ROS elevation and increase the KLA-induced anticancer activity via mitochondrial dysfunction, realizing multimodal treatment of cancer cells with improved therapeutic efficacy.

Hydroxyethyl starch-based self-reinforced nanomedicine inhibits both glutathione and thioredoxin antioxidant pathways to boost reactive oxygen species-powered immunotherapy

The adaptive antioxidant systems of tumor cells, predominantly glutathione (GSH) and thioredoxin (TRX) networks, severely impair photodynamic therapy (PDT) potency and anti-tumor immune responses. Here, a multistage redox homeostasis nanodisruptor (Phy@HES-IR), integrated by hydroxyethyl starch (HES)-new indocyanine green (IR820) conjugates with physcion (Phy), an inhibitor of the pentose phosphate pathway (PPP), is rationally designed to achieve PDT primed cancer immunotherapy. In this nanodisruptor, Phy effectively depletes intracellular GSH of tumor cells by inhibiting 6-phosphogluconate dehydrogenase (6PGD) activity. Concurrently, it is observed for the first time that the modified IR820-NH2 molecule not only exerts PDT action but also interferes with TRX antioxidant pathway by inhibiting thioredoxin oxidase (TRXR) activity. The simultaneous weakening of two major antioxidant pathways of tumor cells is favorable to maximize the PDT efficacy induced by HES-IR conjugates. By virtue of the excellent protecting ability of the plasma expander HES, Phy@HES-IR can remain stable in the blood circulation and efficiently enrich in the tumor region. Consequently, PDT and metabolic modulation synergistically induced immunogenic cell death, which not only suppressed primary tumors but also stimulated potent anti-tumor immunity to inhibit the growth of distant tumors in 4T1 tumor-bearing mice.

Ferroptosis in antitumor therapy: Unraveling regulatory mechanisms and immunogenic potential

Ferroptosis, a recently discovered form of non-apoptotic cell death, has the potential to revolutionize anti-tumor therapy. This review highlights the regulatory mechanisms and immunogenic properties of ferroptosis, and how it can enhance the effectiveness of radio and immunotherapies in overcoming tumor resistance. However, tumor metabolism and the impact of ferroptosis on the tumor microenvironment present challenges in completely realizing its therapeutic potential. A deeper understanding of the effects of ferroptosis on tumor cells and their associated immune cells is essential for developing more effective tumor treatment strategies. This review offers a comprehensive overview of the relationship between ferroptosis and tumor immunity, and sheds new light on its application in tumor immunotherapy.

Cu(II) complex that synergistically potentiates cytotoxicity and an antitumor immune response by targeting cellular redox homeostasis

Developing anticancer drugs with low side effects is an ongoing challenge. Immunogenic cell death (ICD) has received extensive attention as a potential synergistic modality for cancer immunotherapy. However, only a limited set of drugs or treatment modalities can trigger an ICD response and none of them have cytotoxic selectivity. This provides an incentive to explore strategies that might provide more effective ICD inducers free of adverse side effects. Here, we report a metal-based complex (Cu-1) that disrupts cellular redox homeostasis and effectively stimulates an antitumor immune response with high cytotoxic specificity. Upon entering tumor cells, this Cu(II) complex enhances the production of intracellular radical oxidative species while concurrently depleting glutathione (GSH). As the result of heightening cellular oxidative stress, Cu-1 gives rise to a relatively high cytotoxicity to cancer cells, whereas normal cells with low levels of GSH are relatively unaffected. The present Cu(II) complex initiates a potent ferroptosis-dependent ICD response and effectively inhibits in vivo tumor growth in an animal model (c57BL/6 mice challenged with colorectal cancer). This study presents a strategy to develop metal-based drugs that could synergistically potentiate cytotoxic selectivity and promote apoptosis-independent ICD responses through perturbations in redox homeostasis.

A Tumor-Specific Cascade-Activating Smart Prodrug System for Enhanced Targeted Therapy

Developing intelligently targeted drugs with low side effects is urgent for cancer treatment. Toward this goal, a tumor-specific cascade-activating smart prodrug system consisting of a G-quadruplex(G4)-modulated tumor-targeted DNA vehicle and a well-designed cellular stimuli-responsive ligand-drug conjugates (LDCs) is proposed. An original "donor-acceptor" binary fluorescent ligand, with ultrahigh affinity, brightness, and photostability, is engineered to tightly bind G4 structures and significantly improve the nuclease resistance of the DNA vehicle, which serves as a bridge contributing to the construction of the prodrug system, named ApG4/LDCs. Sodium nitroprusside and doxorubicin are loaded into ApG4/LDCs in one pot and generate nitric oxide and superoxide anion in response to cancer cellular environments, which in cascade generates peroxynitrite to cause DNA damage while promoting the self-monitored drug release to achieve enhanced targeted therapy. Such a cascade activation and self-reinforcement process is executed only when the prodrug system targets the tumor tissue followed by cell uptake, showing significant antitumor efficacy and greatly weakening the damage to normal tissues. Given the unique features, the innovative strategy for prodrug design may open a new door to precision disease treatment.

Lactic acid responsive sequential production of hydrogen peroxide and consumption of glutathione for enhanced ferroptosis tumor therapy

Ferroptosis is characterized by the lethal accumulation of lipid reactive oxygen species (ROS), which has great potential for tumor therapy. However, developing new ferroptosis-inducing strategies by combining nanomaterials with small molecule inducers is important. In this study, an enzyme-gated biodegradable natural-product delivery system based on lactate oxidase (LOD)-gated biodegradable iridium (Ir)-doped hollow mesoporous organosilica nanoparticles (HMONs) loaded with honokiol (HNK) (HNK@Ir-HMONs-LOD, HIHL) is designed to enhance ferroptosis in colon tumor therapy. After reaching the tumor microenvironment, the outer LOD dissociates and releases the HNK to induce ferroptosis. Moreover, the released dopant Ir4+ and disulfide-bridged organosilica frameworks deplete intracellular glutathione (GSH), which is followed by GSH-mediated Ir(IV)/Ir(III) conversion. This leads to the repression of glutathione peroxidase 4 (GPX4) activity and decomposition of intratumoral hydrogen peroxide (H2O2) into hydroxyl radicals (•OH) by Ir3+-mediated Fenton-like reactions. Moreover, LOD efficiently depletes lactic acid to facilitate the generation of H2O2 and boost the Fenton reaction, which in turn enhances ROS generation. With the synergistic effects of these cascade reactions and the release of HNK, notable ferroptosis efficacy was observed both in vitro and in vivo. This combination of natural product-induced and lactic acid-responsive sequential production of H2O2 as well as the consumption of glutathione may provide a new paradigm for achieving effective ferroptosis-based cancer therapy.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

Single-Atom Cu Nanozyme-Loaded Bone Scaffolds for Ferroptosis-Synergized Mild Photothermal Therapy in Osteosarcoma Treatment

The rapid multiplication of residual tumor cells and poor reconstruction quality of new bone are considered the major challenges in the postoperative treatment of osteosarcoma. It is a promising candidate for composite bone scaffold which combines photothermal therapy (PTT) and bone regeneration induction for the local treatment of osteosarcoma. However, it is inevitable to damage the normal tissues around the tumor due to the hyperthermia of PTT, while mild heat therapy shows a limited effect on antitumor treatment as the damage can be easily repaired by stress-induced heat shock proteins (HSP). This study reports a new type of single-atom Cu nanozyme-loaded bone scaffolds, which exhibit exceptional photothermal conversion properties as well as peroxidase and glutathione oxidase mimicking activities in vitro experiments. This leads to lipid peroxidation (LPO) and reactive oxygen species (ROS) upregulation, ultimately causing ferroptosis. The accumulation of LPO and ROS also contributes to HSP70 inactivation, maximizing PTT efficiency against tumors at an appropriate therapeutic temperature and minimizing the damage to surrounding normal tissues. Further, the bone scaffold promotes bone regeneration via a continuous release of bioactive ions (Ca2+, P5+, Si4+, and Cu2+). The results of in vivo experiments reveal that scaffolds inhibit tumor growth and promote bone repair.

A Distinctive Insight into Inorganic Sonosensitizers: Design Principles and Application Domains

Sonodynamic therapy (SDT) as a promising non-invasive anti-tumor means features the preferable penetration depth, which nevertheless, usually can't work without sonosensitizers. Sonosensitizers produce reactive oxygen species (ROS) in the presence of ultrasound to directly kill tumor cells, and concurrently activate anti-tumor immunity especially after integration with tumor microenvironment (TME)-engineered nanobiotechnologies and combined therapy. Current sonosensitizers are classified into organic and inorganic ones, and current most reviews only cover organic sonosensitizers and highlighted their anti-tumor applications. However, there have few specific reviews that focus on inorganic sonosensitizers including their design principles, microenvironment regulation, etc. In this review, inorganic sonosensitizers are first classified according to their design rationales rather than composition, and the action rationales and underlying chemistry features are highlighted. Afterward, what and how TME is regulated based on the inorganic sonosensitizers-based SDT nanoplatform with an emphasis on the TME targets-engineered nanobiotechnologies are elucidated. Additionally, the combined therapy and their applications in non-cancer diseases are also outlined. Finally, the setbacks and challenges, and proposed the potential solutions and future directions is pointed out. This review provides a comprehensive and detailed horizon on inorganic sonosensitizers, and will arouse more attentions on SDT.

Intracellular infection-responsive macrophage-targeted nanoparticles for synergistic antibiotic immunotherapy of bacterial infection

Intracellular bacteria are considered to play a key role in the failure of bacterial infection therapy and increase of antibiotic resistance. Nanotechnology-based drug delivery carriers have been receiving increasing attention for improving the intracellular antibacterial activity of antibiotics, but are accompanied by disadvantages such as complex preparation procedures, lack of active targeting, and monotherapy, necessitating further design improvements. Herein, nanoparticles targeting bacteria-infected macrophages are fabricated to eliminate intracellular bacterial infections via antibiotic release and upregulation of intracellular reactive oxygen species (ROS) levels and proinflammatory responses. These nanoparticles were formed through the reaction of the amino group on selenocystamine dihydrochloride and the aldehyde group on oxidized dextran (ox-Dex), which encapsulates vancomycin (Van) through hydrophobic interactions. These nanoparticles could undergo targeted uptake by macrophages via endocytosis and respond to the bacteria-infected intracellular microenvironment (ROS and glutathione (GSH)) for controlled release of antibiotics. Furthermore, these nanoparticles could consume intracellular GSH and promote a significant increase in the level of ROS in macrophages, subsequently up-regulating the proinflammatory response to reinforce antibacterial activity. These nanoparticles can accelerate bacteria-infected wound healing. In this work, nanoparticles were fabricated for bacteria-infected macrophage-targeted and microenvironment-responsive antibiotic delivery, cellular ROS generation, and proinflammatory up-regulation activity to eliminate intracellular bacteria, which opens up a new possibility for multifunctional drug delivery against intracellular infection.

Glutathione-Responsive Polymersome with Continuous Glutathione Depletion for Enhanced Photodynamic Therapy and Hypoxia-Activated Chemotherapy

The high glutathione (GSH) level of the tumor microenvironment severely affects the efficacy of photodynamic therapy (PDT). The current GSH depletion strategies have difficulty meeting the dual needs of security and efficiency. In this study, we report a photosensitizer Chlorin e6 (Ce6) and hypoxia-activated prodrug tirapazamine (TPZ) coloaded cross-linked multifunctional polymersome (TPZ/Ce6@SSPS) with GSH-triggered continuous GSH depletion for enhanced photodynamic therapy and hypoxia-activated chemotherapy. At tumor sites, the disulfide bonds of TPZ/Ce6@SSPS react with GSH to realize decross-linking for on-demand drug release. Meanwhile, the generated highly reactive quinone methide (QM) can further deplete GSH. This continuous GSH depletion will amplify tumor oxidative stress, enhancing the PDT effect of Ce6. Aggravated tumor hypoxia induced by PDT activates the prodrug TPZ, resulting in an enhanced combination of PDT and hypoxia-activated chemotherapy. Both in vitro and in vivo results demonstrate the efficient GSH depletion and potent antitumor activities by TPZ/Ce6@SSPS. This work provides a strategy for the design of a continuous GSH depletion platform, which holds great promise for enhanced combination tumor therapy.

Emerging Chemodynamic Nanotherapeutics for Cancer Treatment

Chemodynamic therapy (CDT) has emerged as a transformative paradigm in the realm of reactive oxygen species -mediated cancer therapies, exhibiting its potential as a sophisticated strategy for precise and effective tumor treatment. CDT primarily relies on metal ions and hydrogen peroxide to initiate Fenton or Fenton-like reactions, generating cytotoxic hydroxyl radicals. Its notable advantages in cancer treatment are demonstrated, including tumor specificity, autonomy from external triggers, and a favorable side-effect profile. Recent advancements in nanomedicine are devoted to enhancing CDT, promising a comprehensive optimization of CDT efficacy. This review systematically elucidates cutting-edge achievements in chemodynamic nanotherapeutics, exploring strategies for enhanced Fenton or Fenton-like reactions, improved tumor microenvironment modulation, and precise regulation in energy metabolism. Moreover, a detailed analysis of diverse CDT-mediated combination therapies is provided. Finally, the review concludes with a comprehensive discussion of the prospects and intrinsic challenges to the application of chemodynamic nanotherapeutics in the domain of cancer treatment.

Engineering H2O2 Self-Supplying Platform for Xdynamic Therapies via Ru-Cu Peroxide Nanocarrier: Tumor Microenvironment-Mediated Synergistic Therapy

Of the most common, hypoxia, overexpressed glutathione (GSH), and insufficient H2O2 concentration in the tumor microenvironment (TME) are the main barriers to the advancment of reactive oxygen species (ROS) mediated Xdynamic therapies (X = photo, chemodynamic, chemo). Maximizing Fenton catalytic efficiency is crucial in chemodynamic therapy (CDT), yet endogenous H2O2 levels are not sufficient to attain better anticancer efficacy. Specifically, there is a need to amplify Fenton reactivity within tumors, leveraging the unique attributes of the TME. Herein, for the first time, we design RuxCu1-xO2-Ce6/CPT (RCpCCPT) anticancer nanoagent for TME-mediated synergistic therapy based on heterogeneous Ru-Cu peroxide nanodots (RuxCu1-xO2 NDs) and chlorine e6 (Ce6), loaded with ROS-responsive thioketal (TK) linked-camptothecin (CPT). The Ru-Cu peroxide NDs (RCp NDs, x = 0.50) possess the highest oxygen vacancy (OV) density, which grants them the potential to form massive Lewis's acid sites for peroxide adsorption, while the dispersibility and targetability of the NDs were improved via surface modification using hyaluronic acid (HA). In TME, RCpCCPT degrades, releasing H2O2, Ru2+/3+, and Cu+/2+ ions, which cooperatively facilitate hydroxyl radical (•OH) formation and deactivate antioxidant GSH enzymes through a cocatalytic loop, resulting in excellent tumor therapeutic efficacy. Furthermore, when combined with laser treatment, RCpCCPT produces singlet oxygen (1O2) for PDT, which induces cell apoptosis at tumor sites. Following ROS generation, the TK linkage is disrupted, releasing up to 92% of the CPT within 48 h. In vitro investigations showed that laser-treated RCpCCPT caused 81.5% cell death from PDT/CDT and chemotherapy (CT). RCpCCPT in cancer cells produces red-blue emission in images of cells taking them in, which allows for fluorescence image-guided Xdynamic treatment. The overall results show that RCp NDs and RCpCCPT are more biocompatible and have excellent Xdynamic therapeutic effectiveness in vitro and in vivo.

Hyaluronan-decorated copper-doxorubicin-anlotinib nanoconjugate for targeted synergistic chemo/chemodynamic/antiangiogenic tritherapy against hepatocellular carcinoma

Copper-based nanomaterials show considerable potential in the chemodynamic therapy of cancers. However, their clinical application is restricted by low catalytic activity in tumor microenvironment and copper-induced tumor angiogenesis. Herein, a novel copper-doxorubicin-anlotinib (CDA) nanoconjugate was constructed by the combination of copper-hydrazide coordination, hydrazone linkage and Schiff base bond. The CDA nanoconjugate consists of a copper-3,3'-dithiobis(propionohydrazide)-doxorubicin core and an anlotinib-hyaluronan shell. Benefiting from hyaluronan camouflage and abundant disulfide bonds and Cu2+, the CDA nanoconjugate possessed excellent tumor-targeting and glutathione-depleting abilities and enhanced chemodynamic efficacy. Released doxorubicin significantly improved copper-mediated chemodynamic therapy by upregulating nicotinamide adenine dinucleotide phosphate oxidase 4 expression to increase intracellular H2O2 level. Furthermore, the nanoconjugate produced excessive •OH to induce lipid peroxidation and mitochondrial dysfunction, thus greatly elevating doxorubicin-mediated chemotherapy. Importantly, anlotinib effectively inhibited the angiogenic potential of copper ions. In a word, the CDA nanoconjugate is successfully constructed by combined coordination and pH-responsive linkages, and displays the great potential of copper-drug conjugate for targeted synergistic chemo/chemodynamic/antiangiogenic triple therapy against cancers.

Glutathione Depletion and Stalwart Anticancer Activity of Metallotherapeutics Inducing Programmed Cell Death: Opening a New Window for Cancer Therapy

The cellular defense system against exogenous substances makes therapeutics inefficient as intracellular glutathione (GSH) exhibits an astounding antioxidant activity in scavenging reactive oxygen species (ROS) or reactive nitrogen species (RNS) or other free radicals produced by the therapeutics. In the cancer cell microenvironment, the intracellular GSH level becomes exceptionally high to fight against oxidative stress created by the production of ROS/RNS or any free radicals, which are the byproducts of intracellular redox reactions or cellular respiration processes. Thus, in order to maintain redox homeostasis for survival of cancer cells and their rapid proliferation, the GSH level starts to escalate. In this circumstance, the administration of anticancer therapeutics is in vain, as the elevated GSH level reduces their potential by reduction or by scavenging the ROS/RNS they produce. Therefore, in order to augment the therapeutic potential of anticancer agents against elevated GSH condition, the GSH level must be depleted by hook or by crook. Hence, this Review aims to compile precisely the role of GSH in cancer cells, the importance of its depletion for cancer therapy and examples of anticancer activity of a few selected metal complexes which are able to trigger cancer cell death by depleting the GSH level.

Radiotherapy-sensitized cancer immunotherapy via cGAS-STING immune pathway by activatable nanocascade reaction

Radiotherapy-induced immune activation holds great promise for optimizing cancer treatment efficacy. Here, we describe a clinically used radiosensitizer hafnium oxide (HfO2) that was core coated with a MnO2 shell followed by a glucose oxidase (GOx) doping nanoplatform (HfO2@MnO2@GOx, HMG) to trigger ferroptosis adjuvant effects by glutathione depletion and reactive oxygen species production. This ferroptosis cascade potentiation further sensitized radiotherapy by enhancing DNA damage in 4T1 breast cancer tumor cells. The combination of HMG nanoparticles and radiotherapy effectively activated the damaged DNA and Mn2+-mediated cGAS-STING immune pathway in vitro and in vivo. This process had significant inhibitory effects on cancer progression and initiating an anticancer systemic immune response to prevent distant tumor recurrence and achieve long-lasting tumor suppression of both primary and distant tumors. Furthermore, the as-prepared HMG nanoparticles "turned on" spectral computed tomography (CT)/magnetic resonance dual-modality imaging signals, and demonstrated favorable contrast enhancement capabilities activated by under the GSH tumor microenvironment. This result highlighted the potential of nanoparticles as a theranostic nanoplatform for achieving molecular imaging guided tumor radiotherapy sensitization induced by synergistic immunotherapy.

Turning Threat to Therapy: A Nanozyme-Patch in Surgical Bed for Convenient Tumor Vaccination by Sustained In Situ Catalysis

Complete surgical resection of tumor is difficult as the invasiveness of cancer, making the residual tumor a lethal threat to patients. The situation is deteriorated by the immune suppression state after surgery, which further nourishes tumor recurrence and metastasis. Immunotherapy is promising to combat tumor metastasis, but is limited by severe toxicity of traditional immunostimulants and complexity of multiple functional units. Here, it is reported that the simple "trans-surgical bed" delivery of Cu2- xSe nanozyme (CSN) by a microneedle-patch can turn the threat to therapy by efficient in situ vaccination. The biocompatible CSN exhibits both peroxidase and glutathione oxidase-like activities, efficiently exhausting glutathione, boosting free radical generation, and inducing immunogenic cell death. The once-for-all inserting of the patch on surgical bed facilitates sustained catalytic action, leading to drastic decrease of recurrence rate and complete suppression of tumor-rechallenge in cured mice. In vivo mechanism interrogation reveals elevated cytotoxic T cell infiltration, re-educated macrophages, increased dendritic cell maturation, and memory T cells formation. Importantly, preliminary metabolism and safety evaluation validated that the metal accumulation is marginable, and the important biochemical indexes are in normal range during therapy. This study has provided a simple, safe, and robust tumor vaccination approach for postsurgical metastasis control.

Spatiotemporally-controlled hydrophobic drug delivery via photosensitizer-driven assembly-disassembly for enhanced triple-negative breast cancer treatment

Therapeutic approaches for triple-negative breast cancer (TNBC) have been continuously advancing, but inadequate control over release behavior, insufficient tumor selectivity, and limited drug availability continue to impede therapeutic outcomes in nanodrug systems. In this study, we propose a general hydrophobic antineoplastic delivery system, termed spatiotemporally-controlled hydrophobic antineoplastic delivery system (SCHADS) for enhanced TNBC treatment. The key feature of SCHADS is the formation of metastable photosensitive-antineoplastic complexes (PACs) through the self-assembly of hydrophobic drugs driven by photosensitive molecules. With the further decoration of tumor-targeting peptides coupled with the EPR effect, the PACs tend to accumulate in the tumor site tremendously, promoting drug delivery efficiency. Meanwhile, the disassembly behavior of the metastable PACs could be driven by light on demand to achieve in situ drug release, thus promoting chemotherapeutics availability. Furthermore, the abundant ROS generated by the photosensitizer could effectively kill tumor cells, ultimately realizing an effective combination of photodynamic and chemotherapeutic therapy. As an exemplary presentation, chlorin e6 has been chosen to drive the formation of PACs with the system xc- inhibitor sorafenib. Compared with pure drug treatment, the PACs with the above-described preponderances exhibit superior therapeutic effects both in vitro and in vivo and circumvent the side effects due to off-target. By manipulating the laser irradiation, the PACs-treated cell death mechanism could be dynamically regulated, thus providing the potential to remedy intrinsic/acquired resistance of tumor. Collectively, this SCHADS achieves spatio-temporal control of the drug that greatly enhances the availability of anticarcinogen and realizes synergistic antitumor effect in TNBC treatment, even ultimately being extended to the treatment of other types of tumors.

Bioactive Layered Double Hydroxides for Synergistic Sonodynamic/Cuproptosis Anticancer Therapy with Elicitation of the Immune Response

Sonodynamic therapy (SDT) has promising application prospects in tumor therapy. However, SDT does not eradicate metastatic tumors. Herein, Cu-substituted ZnAl ternary layered double hydroxide nanosheets (ZCA NSs) were developed as both sonosensitizers and copper nanocarriers for synergistic SDT/cuproptosis cancer therapy. An optimized electronic structure more conducive to the sonodynamic process was obtained from ZCA NSs via the Jahn-Teller effect induced by the introduction of Cu2+, and the synthesized ZCA NSs regulated the intricate tumor microenvironment (TME) by depleting endogenous glutathione (GSH) to amplify oxidative stress for further enhanced SDT performance. Furthermore, cuproptosis was evoked by intracellular overload of Cu2+ and amplified by SDT, leading to irreversible proteotoxicity. In vitro results showed that such synergetic SDT/cuproptosis triggered immunogenic cell death (ICD) and promoted the maturation of dendritic cells (DCs). Furthermore, the as-synthesized ZCA NS-mediated SDT/cuproptosis thoroughly eradicated the in vivo solid tumors and simultaneously elicited antitumor immunity to suppress lung and liver metastasis. Overall, this work established a nanoplatform for synergistic SDT/cuproptosis with a satisfactory antitumor immunity.

Nanoparticle-Catalyzed Transamination under Tumor Microenvironment Conditions: A Novel Tool to Disrupt the Pool of Amino Acids and GSSG in Cancer Cells

Catalytic cancer therapy targets cancer cells by exploiting the specific characteristics of the tumor microenvironment (TME). TME-based catalytic strategies rely on the use of molecules already present in the TME. Amino groups seem to be a suitable target, given the abundance of proteins and peptides in biological environments. Here we show that catalytic CuFe2O4 nanoparticles are able to foster transaminations with different amino acids and pyruvate, another key molecule present in the TME. We observed a significant in cellulo decrease in glutamine and alanine levels up to 48 h after treatment. In addition, we found that di- and tripeptides also undergo catalytic transamination, thereby extending the range of the effects to other molecules such as glutathione disulfide (GSSG). Mechanistic calculations for GSSG transamination revealed the formation of an imine between the oxo group of pyruvate and the free -NH2 group of GSSG. Our results highlight transamination as alternative to the existing toolbox of catalytic therapies.

Overcoming Endosomal Escape Barriers in Gene Drug Delivery Using De Novo Designed pH-Responsive Peptides

A major challenge in using nanocarriers for intracellular drug delivery is their restricted capacity to escape from endosomes into the cytosol. Here, we significantly enhance the drug delivery efficiency by accurately predicting and regulating the transition pH (pH0) of peptides to modulate their endosomal escape capability. Moreover, by inverting the chirality of the peptide carriers, we could further enhance their ability to deliver nucleic acid drugs as well as antitumor drugs. The resulting peptide carriers exhibit versatility in transfecting various cell types with a high efficiency of up to 90% by using siRNA, pDNA, and mRNA. In vivo antitumor experiments demonstrate a tumor growth inhibition of 83.4% using the peptide. This research offers a potent method for the rapid development of peptide vectors with exceptional transfection efficiencies for diverse pathophysiological indications.

Camptothesome-based combination nanotherapeutic regimen for improved colorectal cancer immunochemotherapy

Camptothesome is a sphingomyelin-conjugated camptothecin (SM-CSS-CPT) nanovesicle that fortified the therapeutic delivery of CPT in diverse cancer types. To mitigate the Camptothesome-induced IDO1 negative feedback mechanism, we had co-encapsulated, indoximod (IND, IDO1 inhibitor) into Camptothesome using doxorubicin-derived IND (DOX-IND). To maximize the therapeutic potential of DOX-IND/Camptothesome, herein, we first dissected the synergistic drug ratio (DOX-IND/SM-CSS-CPT) via systematical in vitro screening. DOX-IND/Camptothesome with optimal drug ratio synchronized in vivo drug delivery with significantly higher tumor uptake compared to free drugs. This optimum DOX-IND/Camptothesome outperformed the combination of Camptothesome, Doxil and IND or other IDO1 inhibitors (BMS-986205 or epacadostat) in treating mice bearing late-stage MC38 tumors, and combination with immune checkpoint blockade (ICB) enabled it to eradicate 60 % of large tumors. Further, this optimized co-delivery Camptothesome beat Folfox and Folfiri, two first-line combination chemotherapies for colorectal cancer in antitumor efficacy and exhibited no side effects as compared to the severe systemic toxicities associated with Folfox and Folfiri. Finally, we demonstrated that the synergistic DOX-IND/Camptothesome was superior to the combined use of Onivyde + Doxil + IND in curbing the advanced orthotopic CT26-Luc tumors and eliminated 40 % tumors with complete metastasis remission when cooperated with ICB, eliciting stronger anti-CRC immune responses and greater reversal of immunosuppression. These results corroborated that with precise optimal synergistic drug ratio, the therapeutic potential of DOX-IND/Camptothesome can be fully unleased, which warrants further clinical investigation to benefit the cancer patients.

Adoptive cell therapy for solid tumors beyond CAR-T: Current challenges and emerging therapeutic advances

Adoptive cellular immunotherapy using immune cells expressing chimeric antigen receptors (CARs) is a highly specific anti-tumor immunotherapy that has shown promise in the treatment of hematological malignancies. However, there has been a slow progress toward the treatment of solid tumors owing to the complex tumor microenvironment that affects the localization and killing ability of the CAR cells. Solid tumors with a strong immunosuppressive microenvironment and complex vascular system are unaffected by CAR cell infiltration and attack. To improve their efficacy toward solid tumors, CAR cells have been modified and upgraded by "decorating" and "pruning". This review focuses on the structure and function of CARs, the immune cells that can be engineered by CARs and the transformation strategies to overcome solid tumors, with a view to broadening ideas for the better application of CAR cell therapy for the treatment of solid tumors.

Manganese Dioxide Coated Piezoelectric Nanosonosensitizer for Cancer Therapy with Tumor Microenvironment Remodeling and Multienzyme-Like Catalysis

Sonodynamic therapy (SDT) as an emerging method for cancer therapy has encountered difficulty in insufficient production of reactive oxygen species (ROS), especially in tumor microenvironment (TME) with elevated antioxidants and hypoxic conditions. In this work, the authors have fabricated heterostructured manganese dioxide (MnO2)-coated BaTiO3 nanoparticles (BTO@M NPs) as a piezoelectric sonosensitizer, which exhibits the capacity of remodeling TME and multienzyme-like catalysis for boosting SDT. Benefitting from the piezotronic effect, the formation of a p-n junction between MnO2 and piezoelectric BTO with a built-in electric field and band bending efficiently promotes the separation of charge carriers, facilitating the generation of superoxide anion (•O2 -) and hydroxyl radical (•OH) under ultrasound (US) stimulation. Moreover, BTO@M NPs can catalyze the overexpressed hydrogen peroxide (H2O2) in TME to produce oxygen for replenishing the gas source in SDT, and also deplete antioxidant glutathione (GSH), realizing TME remodeling. During this process, the reduced Mn(II) can convert H2O2 into •OH, further amplifying cellular oxidative damage. With these combination effects, the versatile BTO@M NPs exhibit prominent cytotoxicity and tumor growth inhibition against 4T1 breast cancer. This work provides a feasible strategy for constructing high-efficiency sonosensitizers for cancer SDT.

A Journey of Challenges and Victories: A Bibliometric Worldview of Nanomedicine since the 21st Century

Nanotechnology profoundly affects the advancement of medicine. Limitations in diagnosing and treating cancer and chronic diseases promote the growth of nanomedicine. However, there are very few analytical and descriptive studies regarding the trajectory of nanomedicine, key research powers, present research landscape, focal investigative points, and future outlooks. Herein, articles and reviews published in the Science Citation Index Expanded of Web of Science Core Collection from first January 2000 to 18th July 2023 are analyzed. Herein, a bibliometric visualization of publication trends, countries/regions, institutions, journals, research categories, themes, references, and keywords is produced and elaborated. Nanomedicine-related academic output is increasing since the COVID-19 pandemic, solidifying the uneven global distribution of research performance. While China leads in terms of publication quantity and has numerous highly productive institutions, the USA has advantages in academic impact, commercialization, and industrial value. Nanomedicine integrates with other disciplines, establishing interdisciplinary platforms, in which drug delivery and nanoparticles remain focal points. Current research focuses on integrating nanomedicine and cell ferroptosis induction in cancer immunotherapy. The keyword "burst testing" identifies promising research directions, including immunogenic cell death, chemodynamic therapy, tumor microenvironment, immunotherapy, and extracellular vesicles. The prospects, major challenges, and barriers to addressing these directions are discussed.

A chemo/chemodynamic nanoparticle based on hyaluronic acid induces ferroptosis and apoptosis for triple-negative breast cancer therapy

Triple-negative breast cancer (TNBC) poses a serious threat to women's life and health due to its high malignancy, strong invasiveness, and propensity for early recurrence and metastasis. Therefore, there is an urgent need to develop a highly effective and low-toxic TNBC treatment scheme to enhance the anti-cancer efficacy and prolong the survival of patients. In this work, we designed and synthesized a chemodynamic therapy (CDT) agent (HA-Fc-Mal). The chemo/chemodynamic (CT/CDT) nanoparticle (HCM@DOX) based on hyaluronic acid induces ferroptosis and apoptotic for TNBC therapy was constructed via self-assembled of HA-Fc-Mal and doxorubicin (DOX). HCM@DOX orderly realized the TNBC targeting, controlled DOX release, GSH depletion and induce ROS erupt. In vivo and in vitro experiments confirmed that HCM@DOX inhibited the growth of 4 T1 tumors through ferroptosis and apoptosis, and the tumor inhibition rate was as high as 81.87 %. In addition, HCM@DOX significantly inhibited lung metastasis and exhibited excellent biosafety. Overall, our findings offer a new strategy for TNBC therapy using a CT/CDT nanoparticle that induces ferroptosis and apoptosis.

Recent Advances on NIR-II Light-Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) is a particular oncological therapeutic strategy by generates the highly toxic hydroxyl radical (•OH) from the dismutation of endogenous hydrogen peroxide (H2O2) via Fenton or Fenton-like reactions. However, single CDT therapies have been limited by unsatisfactory efficacy. Enhanced chemodynamic therapy (ECDT) triggered by near-infrared (NIR) is a novel therapeutic modality based on light energy to improve the efficiency of Fenton or Fenton-like reactions. However, the limited penetration and imaging capability of the visible (400-650 nm) and traditional NIR-I region (650-900 nm) light-amplified CDT restrict the prospects for its clinical application. Combined with the high penetration/high precision imaging characteristics of the second near-infrared (NIR-II,) nanoplatform, it is expected to kill deep tumors efficiently while imaging the treatment process in real-time, and more notably, the NIR-II region radiation with wavelengths above 1000 nm can minimize the irradiation damage to normal tissues. Such NIR-II ECDT nanoplatforms have greatly improved the effectiveness of CDT therapy and demonstrated extraordinary potential for clinical applications. Accordingly, various strategies have been explored in the past years to improve the efficiency of NIR-II Enhanced CDT. In this review, the mechanisms and strategies used to improve the performance of NIR-II-enhanced CDT are outlined.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

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.

Mitochondria-targeted ruthenium(II) complexes for photodynamic therapy and GSH detection in living cells

Photodynamic therapy is an emerging tumor therapy that kills tumor cells by activating reactive oxygen species (ROS) produced by photosensitizers. Mitochondria, as an important organelle, are the main generator of cellular ROS. Therefore, the development of photosensitizers capable of targeting mitochondria could significantly enhance the efficacy of photodynamic therapy. In this study, two novel ruthenium(II) complexes, Ru-1 and Ru-2, were designed and synthesized, both of which were functionalized with α,β-unsaturated ketones for sensing of glutathione (GSH). The crystal structures of the two complexes were determined and they exhibited good recognition of GSH by off-on luminescence signals. The complex Ru-2 containing aromatic naphthalene can enter the cells and react with GSH to generate a strong luminescence signal that can be used to monitor intracellular GSH levels through imaging. Ru-2 also has an excellent mitochondrial localization ability with a Pearson's coefficient of 0.95, which demonstrates that it can efficiently target the mitochondria of tumor cells to enhance the effectiveness of photodynamic therapy as a photosensitizer.

Enhancing lipid peroxidation via radical chain transfer reaction for MRI guided and effective cancer therapy in mice

Lipid peroxidation (LPO), the process of membrane lipid oxidation, is a potential new form of cell death for cancer treatment. However, the radical chain reaction involved in LPO is comprised of the initiation, propagation (the slowest step), and termination stages, limiting its effectiveness in vivo. To address this limitation, we introduce the radical chain transfer reaction into the LPO process to target the propagation step and overcome the sluggish rate of lipid peroxidation, thereby promoting endogenous lipid peroxidation and enhancing therapeutic outcomes. Firstly, radical chain transfer agent (CTA-1)/Fe nanoparticles (CTA-Fe NPs-1) was synthesized. Notably, CTA-1 convert low activity peroxyl radicals (ROO·) into high activity alkoxyl radicals (RO·), creating the cycle of free radical oxidation and increasing the propagation of lipid peroxidation. Additionally, CTA-1/Fe ions enhance reactive oxygen species (ROS) generation, consume glutathione (GSH), and thereby inactivate GPX-4, promoting the initiation stage and reducing termination of free radical reaction. CTA-Fe NPs-1 induce a higher level of peroxidation of polyunsaturated fatty acids in lipid membranes, leading to highly effective treatment in cancer cells. In addition, CTA-Fe NPs-1 could be enriched in tumors inducing potent tumor inhibition and exhibit activatable T1-MRI contrast of magnetic resonance imaging (MRI). In summary, CTA-Fe NPs-1 can enhance intracellular lipid peroxidation by accelerating initiation, propagation, and inhibiting termination step, promoting the cycle of free radical reaction, resulting in effective anticancer outcomes in tumor-bearing mice.

Hyperbaric Oxygen Boosts Antitumor Efficacy of Copper-Diethyldithiocarbamate Nanoparticles against Pancreatic Ductal Adenocarcinoma by Regulating Cancer Stem Cell Metabolism

Cuproptosis-based cancer nanomedicine has received widespread attention recently. However, cuproptosis nanomedicine against pancreatic ductal adenocarcinoma (PDAC) is severely limited by cancer stem cells (CSCs), which reside in the hypoxic stroma and adopt glycolysis metabolism accordingly to resist cuproptosis-induced mitochondria damage. Here, we leverage hyperbaric oxygen (HBO) to regulate CSC metabolism by overcoming tumor hypoxia and to augment CSC elimination efficacy of polydopamine and hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@PH NPs). Mechanistically, while HBO and CuET@PH NPs inhibit glycolysis and oxidative phosphorylation, respectively, the combination of HBO and CuET@PH NPs potently suppresses energy metabolism of CSCs, thereby achieving robust tumor inhibition of PDAC and elongating mice survival importantly. This study reveals novel insights into the effects of cuproptosis nanomedicine on PDAC CSC metabolism and suggests that the combination of HBO with cuproptosis nanomedicine holds significant clinical translation potential for PDAC patients.

Ferroptosis in cancer: From molecular mechanisms to therapeutic strategies

Ferroptosis is a non-apoptotic form of regulated cell death characterized by the lethal accumulation of iron-dependent membrane-localized lipid peroxides. It acts as an innate tumor suppressor mechanism and participates in the biological processes of tumors. Intriguingly, mesenchymal and dedifferentiated cancer cells, which are usually resistant to apoptosis and traditional therapies, are exquisitely vulnerable to ferroptosis, further underscoring its potential as a treatment approach for cancers, especially for refractory cancers. However, the impact of ferroptosis on cancer extends beyond its direct cytotoxic effect on tumor cells. Ferroptosis induction not only inhibits cancer but also promotes cancer development due to its potential negative impact on anticancer immunity. Thus, a comprehensive understanding of the role of ferroptosis in cancer is crucial for the successful translation of ferroptosis therapy from the laboratory to clinical applications. In this review, we provide an overview of the recent advancements in understanding ferroptosis in cancer, covering molecular mechanisms, biological functions, regulatory pathways, and interactions with the tumor microenvironment. We also summarize the potential applications of ferroptosis induction in immunotherapy, radiotherapy, and systemic therapy, as well as ferroptosis inhibition for cancer treatment in various conditions. We finally discuss ferroptosis markers, the current challenges and future directions of ferroptosis in the treatment of cancer.

The application of nanoparticles-based ferroptosis, pyroptosis and autophagy in cancer immunotherapy

Immune checkpoint blockers (ICBs) have been applied for cancer therapy and achieved great success in the field of cancer immunotherapy. Nevertheless, the broad application of ICBs is limited by the low response rate. To address this issue, increasing studies have found that the induction of immunogenic cell death (ICD) in tumor cells is becoming an emerging therapeutic strategy in cancer treatment, not only straightly killing tumor cells but also enhancing dying cells immunogenicity and activating antitumor immunity. ICD is a generic term representing different cell death modes containing ferroptosis, pyroptosis, autophagy and apoptosis. Traditional chemotherapeutic agents usually inhibit tumor growth based on the apoptotic ICD, but most tumor cells are resistant to the apoptosis. Thus, the induction of non-apoptotic ICD is considered to be a more efficient approach for cancer therapy. In addition, due to the ineffective localization of ICD inducers, various types of nanomaterials have been being developed to achieve targeted delivery of therapeutic agents and improved immunotherapeutic efficiency. In this review, we briefly outline molecular mechanisms of ferroptosis, pyroptosis and autophagy, as well as their reciprocal interactions with antitumor immunity, and then summarize the current progress of ICD-induced nanoparticles based on different strategies and illustrate their applications in the cancer therapy.

Cholesterol-modified sphingomyelin chimeric lipid bilayer for improved therapeutic delivery

Cholesterol (Chol) fortifies packing and reduces fluidity and permeability of the lipid bilayer in vesicles (liposomes)-mediated drug delivery. However, under the physiological environment, Chol is rapidly extracted from the lipid bilayer by biomembranes, which jeopardizes membrane stability and results in premature leakage for delivered payloads, yielding suboptimal clinic efficacy. Herein, we report a Chol-modified sphingomyelin (SM) lipid bilayer via covalently conjugating Chol to SM (SM-Chol), which retains membrane condensing ability of Chol. Systemic structure activity relationship screening demonstrates that SM-Chol with a disulfide bond and longer linker outperforms other counterparts and conventional phospholipids/Chol mixture systems on blocking Chol transfer and payload leakage, increases maximum tolerated dose of vincristine while reducing systemic toxicities, improves pharmacokinetics and tumor delivery efficiency, and enhances antitumor efficacy in SU-DHL-4 diffuse large B-cell lymphoma xenograft model in female mice. Furthermore, SM-Chol improves therapeutic delivery of structurally diversified therapeutic agents (irinotecan, doxorubicin, dexamethasone) or siRNA targeting multi-drug resistant gene (p-glycoprotein) in late-stage metastatic orthotopic KPC-Luc pancreas cancer, 4T1-Luc2 triple negative breast cancer, lung inflammation, and CT26 colorectal cancer animal models in female mice compared to respective FDA-approved nanotherapeutics or lipid compositions. Thus, SM-Chol represents a promising platform for universal and improved drug delivery.

Synergistic Glutathione Depletion and STING Activation to Potentiate Dendritic Cell Maturation and Cancer Vaccine Efficacy

Dendritic cell (DC) maturation and antigen presentation are key factors for successful vaccine-based cancer immunotherapy. This study developed manganese-based layered double hydroxide (Mn-LDH) nanoparticles as a self-adjuvanted vaccine carrier that not only promoted DC maturation through synergistically depleting endogenous glutathione (GSH) and activating STING signaling pathway, but also facilitated the delivery of model antigen ovalbumin (OVA) into lymph nodes and subsequent antigen presentation in DCs. Significant therapeutic-prophylactic efficacy of the OVA-loaded Mn-LDH (OVA/Mn-LDH) nanovaccine was determined by the tumor growth inhibition in the mice bearing B16-OVA tumor. Our results showed that the OVA/Mn-LDH nanoparticles could be a potent delivery system for cancer vaccine development without the need of adjuvant. Therefore, the combination of GSH exhaustion and STING pathway activation might be an advisable approach for promoting DC maturation and antigen presentation, finally improving cancer vaccine efficacy.

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

Immunotherapy harnesses the inherent immune system in the body to generate systemic antitumor immunity, offering a promising modality for defending against cancer. However, tumor immunosuppression and evasion seriously restrict the immune response rates in clinical settings. Catalytic nanomedicines can transform tumoral substances/metabolites into therapeutic products in situ, offering unique advantages in antitumor immunotherapy. Through catalytic reactions, both tumor eradication and immune regulation can be simultaneously achieved, favoring the development of systemic antitumor immunity. In recent years, with advancements in catalytic chemistry and nanotechnology, catalytic nanomedicines based on nanozymes, photocatalysts, sonocatalysts, Fenton catalysts, electrocatalysts, piezocatalysts, thermocatalysts and radiocatalysts have been rapidly developed with vast applications in cancer immunotherapy. This review provides an introduction to the fabrication of catalytic nanomedicines with an emphasis on their structures and engineering strategies. Furthermore, the catalytic substrates and state-of-the-art applications of nanocatalysts in cancer immunotherapy have also been outlined and discussed. The relationships between nanostructures and immune regulating performance of catalytic nanomedicines are highlighted to provide a deep understanding of their working mechanisms in the tumor microenvironment. Finally, the challenges and development trends are revealed, aiming to provide new insights for the future development of nanocatalysts in catalytic immunotherapy.