An acid-responsive MOF nanomedicine for augmented anti-tumor immunotherapy via a metal ion interference-mediated pyroptotic pathway.

Pyroptosis is an inflammatory form of programmed cell death (PCD) that is regulated by the Gasdermin protein family in response to various stimuli, playing a critical role in the development of tumor therapy strategies. However, cancers are generally known to escape from PCD via immunosuppressive pathways or other resistant mechanisms. In this study, an acid-responsive Fe/Mn bimetal-organic framework nanosystem carrying metal ions and immune adjuvant R848 (FeMn@R@H) was designed for combining pyroptosis and augmented immunotherapy. The FeMn@R@H would be triggered to disintegrate and release Fe3+ and Mn2+ ions in response to the acidic tumor microenvironment (TME), thereby initiating Fenton-like reactions for ROS-mediated pyroptosis. On the one hand, the pyroptosis-caused cell rupture would induce the release of proinflammatory cytokines and immunogenic constituents from tumor cells, further resulting in immunogenic cell death (ICD) to promote antitumor immune responses. On the other hand, the co-delivered R848 could reverse suppressive tumor immune microenvironment (TIME) and induce inflammatory responses by activating the TLR7/8 pathway. In conclusion, this tumor-specific therapy system can co-deliver metal ions and R848 to tumor tissues to perform pyroptosis-mediated PCD and augmented anti-tumor immunotherapy.

Bioactivable STING Nanoagonists to Synergize NIR-II Mild Photothermal Therapy Primed Robust and Long-Term Anticancer Immunity.

Pharmacological activation of the stimulator of interferon genes (STING) pathway has become a promising strategy for cancer immunotherapy. However, the insufficient tumorous accumulation, rapid clearance, and short duration of drug efficacy in the tumor microenvironment of small structural STING agonists greatly compromise the therapeutic efficacy. Herein, a tumorous extracellular matrix (ECM) is presented anchoring STING agonist-based photoimmunothernostic nanomedicine (SAPTN) that can be activated by mild-temperature photothermal therapy (mild PTT) induced neutrophilic inflammation. The SAPTN owns second window near-infrared (NIR-II) photonics properties fitting for NIR-II fluorescence and photoacoustic imaging-guided cancer therapy. The aggregates SAPTN targeting to the ECM provide slow and continuous release of potent STING agonists diABZIs. The mild PTT and long-lasting STING agonists released in the ECM synergistically prime systematic, robust, and long-term anticancer immunity. In a tumor model, this approach leads to complete tumor eradication in about 100% of mice with orthotopic breast tumors, and the mice regained tumor-free survival of at least 2 months. In addition, the immune-mediated abscopal effect shows inhibition of the distant solid tumor growth by intratumoral administration of SAPTN with laser irradiation. Overall, this approach represents a generalized photoactivable nanomedicine to prime anticancer immunity for improved cancer theranostics.

A Cascade Targeted and Mitochondrion-Dysfunctional Nanomedicine Capable of Overcoming Drug Resistance in Hepatocellular Carcinoma.

Chemoresistance is a formidable issue in clinical anticancer therapy and is pertinent to the lowered efficacies of chemotherapeutics and the activated tumor self-repairing proceedings. Herein, bifunctional amphiphiles containing galactose ligands and high-density disulfide are synthesized for encapsulating mitochondrion-targeting tetravalent platinum prodrugs to construct a cascade targeted and mitochondrion-dysfunctional nanomedicine (Gal-NP@TPt). Subsequent investigations verify that Gal-NP@TPt with sequential targeting functions toward tumors and mitochondria improved the spatiotemporal level of platinum. In addition, glutathione depletion by Gal-NP@TPt appear to substantially inhibit the proceedings of platinum detoxification, inducing the susceptibility to the mitochondrial platinum. Moreover, the strategic transportation of platinum to mitochondria lacking DNA repair machinery by Gal-NP@TPt lowers the possibility of platinum deactivation. Eventually, Gal-NP@TPt demonstrates appreciable antitumor effects for the systemic treatment of patient-derived tumor xenografts of hepatocellular carcinoma. Note that these strategies in overcoming drug resistance have also been confirmed to be valid based on genome-wide analysis via RNA-sequencing. Therefore, an intriguing multifunctional nanomedicine capable of resolving formidable chemoresistance is achieved, which should be greatly emphasized in practical applications for the treatment of intractable tumors.

Carrier-Free Immunotherapeutic Nano-Booster with Dual Synergistic Effects Based on Glutaminase Inhibition Combined with Photodynamic Therapy.

The immunotherapeutic effect elicited by photodynamic therapy (PDT) is attenuated by tumor defense mechanisms associated with glutamine metabolism, including the metabolic regulation of redox homeostasis and the limitation of the immunosuppressive tumor microenvironment (ITM). Herein, a carrier-free immunotherapeutic nanobooster C9SN with dual synergistic effects was constructed by the self-assembly of glutaminase (GLS) inhibitor compound 968 (C968) and photosensitizer Chlorin e6. C968-mediated GSH deprivation through inhibiting glutamine metabolism prevented PDT-generated reactive oxygen species from being annihilated by GSH, amplifying intracellular oxidative stress, which caused severe cell death and also enhanced the immunogenic cell death (ICD) effect. In addition, genome-wide analysis was carried out using RNA-sequencing to evaluate the changes in cell transcriptome induced by amplifying oxidative stress. Thereafter, neoantigens generated by the enhanced ICD effect promoted the maturation of dendritic cells, thereby recruiting and activating cytotoxic T lymphocytes (CTLs). Meanwhile, C9SN remodeled the ITM by blocking glutamine metabolism to polarize M2-type tumor-associated macrophages (TAMs) into M1-type TAMs, which further recruited and activated the CTLs. Ultimately, this immunotherapeutic nanobooster suppressed primary and distant tumors. This "kill two birds with one stone" strategy would shed light on enhancing tumor immunogenicity and alleviating tumor immunosuppression to improve the immunotherapeutic effect of PDT.

Glutamine metabolism targeting liposomes for synergistic chemosensitization and starvation therapy in ovarian cancer.

Platinum-based chemotherapy is a first-line therapeutic regimen against ovarian cancer (OC); however, the therapeutic potential is always reduced by glutamine metabolism. Herein, a valid strategy of inhibiting glutamine metabolism was proposed to cause tumor starvation and chemosensitization. Specifically, reactive oxygen species-responsive liposomes were developed to co-deliver cisplatin (CDDP) and bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to CDDP by reducing glutathione generation to prevent CDDP detoxification, suppressing ATP production to avoid CDDP efflux, hindering nucleotide synthesis to aggravate DNA damage induced by CDDP, and blocking mammalian target of rapamycin (mTOR) signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs. STATEMENT OF SIGNIFICANCE: This work proposed a valid strategy of inhibiting glutamine metabolism to cause tumor starvation and chemosensitization. Specifically, ROS-responsive liposomes were developed to co-deliver cisplatin CDDP and BPTES [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to cisplatin by reducing glutathione generation to prevent cisplatin detoxification, suppressing ATP production to avoid cisplatin efflux, hindering nucleotide synthesis to aggravate DNA damage induced by cisplatin, and blocking mTOR signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs.

Synergetic delivery of artesunate and isosorbide 5-mononitrate with reduction-sensitive polymer nanoparticles for ovarian cancer chemotherapy.

Ovarian cancer is a highly fatal gynecologic malignancy worldwide. Chemotherapy remains the primary modality both for primary and maintenance treatments of ovarian cancer. However, the progress in developing chemotherapeutic agents for ovarian cancer has been slow in the past 20 years. Thus, new and effective chemotherapeutic drugs are urgently needed for ovarian cancer treatment. A reduction-responsive synergetic delivery strategy (PSSP@ART-ISMN) with co-delivery of artesunate and isosorbide 5-mononitrate was investigated in this research study. PSSP@ART-ISMN had various effects on tumor cells, such as (i) inducing the production of reactive oxygen species (ROS), which contributes to mitochondrial damage; (ii) providing nitric oxide and ROS for the tumor cells, which further react to generate highly toxic reactive nitrogen species (RNS) and cause DNA damage; and (iii) arresting cell cycle at the G0/G1 phase and inducing apoptosis. PSSP@ART-ISMN also demonstrated excellent antitumor activity with good biocompatibility in vivo. Taken together, the results of this work provide a potential delivery strategy for chemotherapy in ovarian cancer.

NO-dependent vasodilation and deep tumor penetration for cascade-amplified antitumor performance.

Nonspecific biodistribution and poor permeability of conventional therapeutic agents in solid tumors severely compromised the antitumor efficacy. Herein, we report a cascade tumor therapeutic nanoplatform consisting of docosahexaenoic acid (DHA) and nicorandil (NI), namely DNP, to specifically produce cytotoxic agents in tumor cells as well as dilating blood vessels to increase the intratumoral oxidative stress levels. The DHA embedded in the membrane could generate reactive oxygen species (ROS) meanwhile NI produced nitric oxide (NO) in response to intracellular glutathione (GSH) in tumors. Notably, the two functional species could further react in situ to form a more tumoricidal reactive nitrogen species (RNS), causing selectively cascade amplification of antitumor performance. In addition, NO-induced vasodilation could consequently result in a series of functions, including hypoxia relief and deep tumor transportation. In general, we anticipate that the DNP could show great potential for tumor-specific treatment by selectively producing RNS precursors in response to the interior environment of tumor cells for hypoxia normalization and tumor inhibition.