Kilogram scale facile synthesis and systematic characterization of a Gd-macrochelate as T1-weighted magnetic resonance imaging contrast agent.

To overcome the problems of commercial magnetic resonance imaging (MRI) contrast agents (CAs) (i.e., small molecule Gd chelates), we have proposed a new concept of Gd macrochelates based on the coordination of Gd3+ and macromolecules, e.g., poly(acrylic acid) (PAA). To further decrease the r2/r1 ratio of the reported Gd macrochelates that is an important factor for T1 imaging, in this study, a superior macromolecule hydrolyzed polymaleic anhydride (HPMA) was found to coordinate Gd3+. The synthesis conditions were optimized and the generated Gd-HPMA macrochelate was systematically characterized. The obtained Gd-HPMA29 synthesized in a 100 L of reactor has a r1 value of 16.35 mM-1 s-1 and r2/r1 ratio of 2.05 at 7.0 T, a high Gd yield of 92.7% and a high product weight (1074 g), which demonstrates the feasibility of kilogram scale facile synthesis. After optimization of excipients and sterilization at a high temperature, the obtained Gd-HPMA30 formulation has a pH value of 7.97, osmolality of 691 mOsmol/kg water, density of 1.145 g/mL, and viscosity of 2.2 cP at 20 â„ƒ or 1.8 cP at 37 â„ƒ, which meet all specifications and physicochemical criteria for clinical injections indicating the immense potential for clinical applications.

Kilogram-Scale Synthesis of Extremely Small Gadolinium Oxide Nanoparticles as a T1-Weighted Contrast Agent for Magnetic Resonance Imaging.

Magnetic resonance imaging contrast agents are frequently used in clinics to enhance the contrast between diseased and normal tissues. The previously reported poly(acrylic acid) stabilized exceedingly small gadolinium oxide nanoparticles (ES-GdON-PAA) overcame the problems of commercial Gd chelates, but limitations still exist, i.e., high r2/r1 ratio, long blood circulation half-life, and no data for large scale synthesis and formulation optimization. In this study, polymaleic acid (PMA) is found to be an ideal stabilizer to synthesize ES-GdONs. Compared with ES-GdON-PAA, the PMA-stabilized ES-GdON (ES-GdON-PMA) has a lower r2/r1 ratio (2.05, 7.0 T) and a lower blood circulation half-life (37.51 min). The optimized ES-GdON-PMA-9 has an exceedingly small particle size (2.1 nm), excellent water dispersibility, and stability. A facile, efficient, and environmental friendly synthetic method is developed for large-scale synthesis of the ES-GdONs-PMA. The weight of the optimized freeze-dried ES-GdON-PMA-26 synthesized in a 20 L of reactor reaches the kilogram level. The formulation optimization is also finished, and the concentrated ES-GdON-PMA-26 formulation (CGd = 100 mm) after high-pressure steam sterilization possesses eligible physicochemical properties (i.e., pH value, osmolality, viscosity, and density) for investigational new drug application.

Gadolinium Oxide Nanoparticles Reinforce the Fractionated Radiotherapy-Induced Immune Response in Tri-Negative Breast Cancer via cGAS-STING Pathway.

Introduction: Radiotherapy is a widely recognized first-line clinical treatment for cancer, but its efficacy may be impeded by the radioresistance of advanced tumors. It is urgent to improve the sensitivity of radioresistant tumors to radiotherapy. In this work, gadolinium oxide nanocrystals (GONs) were utilized as radiosensitizers to enhance the killing effect and reinforce the immune activation of X-ray irradiation on 4T1 breast cancer cells in vitro and in vivo. Methods: 1.0 T small animal MR imaging (MRI) system was employed to trace GONs in vivo, while 225 kVp X-ray irradiation equipment was utilized for investigating the radiosensitization of GONs in 4T1 breast cancer cells in vitro and in vivo. Western blot, quantitative real-time PCR (RT-qPCR), immunohistochemistry, immunofluorescence, clonal survival assay, flow cytometry and reactive oxygen species assay were used to explore the biological mechanism of GON sensitization. Results: GONs exhibited exceptional utility as contrast agents for both in vivo and in vitro MRI imaging. Interestingly, a single dose of 8.0 Gy X-rays together with GONs failed to confer superior therapeutic effects in tumor-bearing mice, while only 3.0 Gy × 3 fractions X-rays combined with GONs exhibited effective tumor growth inhibition. Moreover, fractionated X-ray irradiation with GONs demonstrated a superior capacity to activate the cGAS-STING pathway. Discussion: Fractionated X-ray irradiation in the presence of GONs has demonstrated the most significant activation of the anti-tumor immune response by boosting the cGAS-STING pathway.

Ultrasmall Self-Cascade AuNP@FeS Nanozyme for H2S-Amplified Ferroptosis Therapy.

Recently, nanozymes with peroxidase (POD)-like activity have shown great promise for ferroptosis-based tumor therapy, which are capable of transforming hydrogen peroxide (H2O2) to highly toxic hydroxyl radicals (•OH). However, the unsatisfactory therapeutic performance of nanozymes due to insufficient endogenous H2O2 and acidity at tumor sites has always been a conundrum. Herein, an ultrasmall gold (Au) @ ferrous sulfide (FeS) cascade nanozyme (AuNP@FeS) with H2S-releasing ability constructed with an Au nanoparticle (AuNP) and an FeS nanoparticle (FeSNP) is designed to increase the H2O2 level and acidity in tumor cells via the collaboration between cascade reactions of AuNP@FeS and the biological effects of released H2S, achieving enhanced •OH generation as well as effective ferroptosis for tumor therapy. The cascade reaction in tumor cells is activated by the glucose oxidase (GOD)-like activity of AuNP in AuNP@FeS to catalyze intratumoral glucose into H2O2 and gluconic acid; meanwhile, the released H2S from AuNP@FeS reduces H2O2 consumption by inhibiting intracellular catalase (CAT) activity and promotes lactic acid accumulation. The two pathways synergistically boost H2O2 and acidity in tumor cells, thus inducing a cascade to generate abundant •OH by catalyzing H2O2 through the POD-like activity of FeS in AuNP@FeS and ultimately causing amplified ferroptosis. In vitro and in vivo experiments demonstrated that AuNP@FeS presents a superior tumor therapeutic effect compared to that of AuNP or FeS alone. This strategy represents a simple but powerful method to amplify ferroptosis with H2S-releasing cascade nanozymes and will pave a new way for the development of tumor therapy.

Tumor-Generated Reactive Oxygen Species Storm for High-Performance Ferroptosis Therapy.

Ferroptosis therapy (FT) efficacy of tumors suffers from a relatively low concentration of Fenton agents, limited hydrogen peroxide (H2O2) content, and insufficient acidity in the tumor environment (TME), which are unfavorable for reactive oxygen species (ROS) generation based on Fenton or Fenton-like reactions. The glutathione (GSH) overexpression in TME can scavenge ROS and abate the FT performance. In this study, a strategy of ROS storm generation specifically initiated by the TME and our developed nanoplatforms (TAF-HMON-CuP@PPDG) is proposed for high-performance FT of tumors. The GSH in the TME initiates HMON degradation, resulting in tamoxifen (TAF) and copper peroxide (CuP) release from TAF3-HMON-CuP3@PPDG. The released TAF leads to enhanced acidification within tumor cells, which reacts with the released CuP producing Cu2+ and H2O2. The Fenton-like reaction between Cu2+ and H2O2 generates ROS and Cu+, and that between Cu+ and H2O2 generates ROS and Cu2+, forming a cyclic catalysis effect. Cu2+ reacts with GSH to generate Cu+ and GSSG. The increased acidification by TAF can accelerate the Fenton-like reaction between Cu+ and H2O2. The GSH consumption decreases the glutathione peroxidase 4 (GPX4) expression. All of the above reactions generate a ROS storm in tumor cells for high-performance FT, which is demonstrated in cancer cells and tumor-bearing mice.

A Strategy of Fenton Reaction Cycloacceleration for High-Performance Ferroptosis Therapy Initiated by Tumor Microenvironment Remodeling.

The emerging tumor ferroptosis therapy confronts impediments of the tumor microenvironment (TME) with weak intrinsic acidity, inadequate endogenous H2 O2 , and a powerful intracellular redox balance system that eliminates toxic reactive oxygen species (ROS). Herein, a strategy of Fenton reaction cycloacceleration initiated by remodeling the TME for magnetic resonance imaging (MRI)-guided high-performance ferroptosis therapy of tumors is proposed. The synthesized nanocomplex exhibits enhanced accumulation at carbonic anhydrase IX (CAIX)-positive tumors based on the CAIX-mediated active targeting, and increased acidification via the inhibition of CAIX by 4-(2-aminoethyl) benzene sulfonamide (ABS) (remodeling TME). This accumulated H+ and abundant glutathione in TME synergistically trigger biodegradation of the nanocomplex to release the loaded cuprous oxide nanodots (CON), ß-lapachon (LAP), Fe3+ , and gallic acid-ferric ions coordination networks (GF). The Fenton and Fenton-like reactions are cycloaccelerated via the catalytic loop of Fe-Cu, and the LAP-triggered and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase1-mediated redox cycle, generating robust ROS and plenitudinous lipid peroxides accumulation for ferroptosis of tumor cells. The detached GF network has improved relaxivities in response to the TME. Therefore, the strategy of Fenton reaction cycloacceleration initiated by remodeling the TME is promising for MRI-guided high-performance ferroptosis therapy of tumors.

Cycloacceleration of Reactive Oxygen Species Generation Based on Exceedingly Small Magnetic Iron Oxide Nanoparticles for Tumor Ferroptosis Therapy.

Because of the insufficiency of hydrogen peroxide, the relatively low rate of Fenton reaction, and the active glutathione (GSH) peroxidase 4 (GPX4) in tumor cells, it is difficult to achieve a desirable efficacy of ferroptosis therapy (FT) for tumors based on nanomaterials. Inspired by the concept of "cyclotron" in physics, in this study, a new concept of cycloacceleration of reactive oxygen species (ROS) generation in tumor cells to realize high-performance FT of tumors is proposed. Typically, a magnetic resonance imaging (MRI) contrast agent of dotted core-shell Fe3 O4 /Gd2 O3 hybrid nanoparticles (FGNPs) is prepared based on exceedingly small magnetic iron oxide nanoparticles (ES-MIONs). Sorafenib (SFN) is loaded and poly(ethylene glycol) methyl ether-poly(propylene sulfide)-NH2 (mPEG-PPS-NH2 ) is grafted on the surface of FGNP to generate SA-SFN-FGNP via self-assembly. The results of in vitro and in vivo demonstrate SA-SFN-FGNP can work with the acidic tumor microenvironment and endosomal conditions, Fenton reaction and system XC - , and generate cyclic reactions in tumor cells, resulting in specific cycloacceleration of ROS generation for high-performance FT of tumors. The very high longitudinal relaxivity (r1 , 33.43 mM-1 s-1 , 3.0 T) makes sure that the SA-SFN-FGNP can be used for MRI-guided FT of tumors.

GSA Central-A web platform to perform, learn, and discuss gene set analysis.

Gene Set Analysis (GSA) is one of the most commonly used strategies to analyze omics data. Hundreds of GSA-related papers have been published, giving birth to a GSA field in Bioinformatics studies. However, as the field grows, it is becoming more difficult to obtain a clear view of all available methods, resources, and their quality. In this paper, we introduce a web platform called "GSA Central" which, as its name indicates, acts as a focal point to centralize GSA information and tools useful to beginners, average users, and experts in the GSA field. "GSA Central" contains five different resources: A Galaxy instance containing GSA tools ("Galaxy-GSA"), a portal to educational material ("GSA Classroom"), a comprehensive database of articles ("GSARefDB"), a set of benchmarking tools ("GSA BenchmarKING"), and a blog ("GSA Blog"). We expect that "GSA Central" will become a useful resource for users looking for introductory learning, state-of-the-art updates, method/tool selection guidelines and insights, tool usage, tool integration under a Galaxy environment, tool design, and tool validation/benchmarking. Moreover, we expect this kind of platform to become an example of a "thematic platform" containing all the resources that people in the field might need, an approach that could be extended to other bioinformatics topics or scientific fields.

Biodegradable and biocompatible exceedingly small magnetic iron oxide nanoparticles for T1-weighted magnetic resonance imaging of tumors.

Magnetic resonance imaging (MRI) has been widely using in clinical diagnosis, and contrast agents (CAs) can improve the sensitivity MRI. To overcome the problems of commercial Gd chelates-based T1 CAs, commercial magnetic iron oxide nanoparticles (MIONs)-based T2 CAs, and reported exceedingly small MIONs (ES-MIONs)-based T1 CAs, in this study, a facile co-precipitation method was developed to synthesize biodegradable and biocompatible ES-MIONs with excellent water-dispersibility using poly (aspartic acid) (PASP) as a stabilizer for T1-weighted MRI of tumors. After optimization of the synthesis conditions, the final obtained ES-MION9 with 3.7 nm of diameter has a high r1 value (7.0 ± 0.4 mM-1 s-1) and a low r2/r1 ratio (4.9 ± 0.6) at 3.0 T. The ES-MION9 has excellent water dispersibility because of the excessive -COOH from the stabilizer PASP. The pharmacokinetics and biodistribution of ES-MION9 in vivo demonstrate the better tumor targetability and MRI time window of ES-MION9 than commercial Gd chelates. T1-weighted MR images of aqueous solutions, cells and tumor-bearing mice at 3.0 T or 7.0 T demonstrate that our ES-MION9 has a stronger capability of enhancing the MRI contrast comparing with the commercial Gd chelates. The MTT assay, live/dead staining of cells, and H&E-staining indicate the non-toxicity and biosafety of our ES-MION9. Consequently, the biodegradable and biocompatible ES-MION9 with excellent water-dispersibility is an ideal T1-weighted CAs with promising translational possibility to compete with the commercial Gd chelates.

A tumor microenvironment dual responsive contrast agent for contrary contrast-magnetic resonance imaging and specific chemotherapy of tumors.

Development of magnetic resonance imaging (MRI) contrast agents (CAs) is still one of the research hotspots due to the inherent limitations of T1- or T2-weighted CAs and T1/T2 dual-mode CAs. To dramatically enhance the MRI contrast between tumors and normal tissues, we propose a new concept of contrary contrast-MRI (CC-MRI), whose specific definition is that CC-MRI CAs present a positive or negative signal at normal tissues, but show contrary signals at diseased tissues. To realize CC-MRI of tumors, we designed and developed a tumor microenvironment (TME) dual responsive CA (i.e., SA-FeGdNP-DOX@mPEG), which is almost not responsive under normal physiological conditions, but highly responsive to the acidic and reductive TME. Our SA-FeGdNP-DOX@mPEG shows a negative MRI signal under normal physiological conditions due to the high r2 value (336.9 mM-1 s-1) and high r2/r1 ratio (18.4), but switches to a positive MRI signal in the TME because of the high r1 value (20.32 mM-1 s-1) and low r2/r1 ratio (7.2). Our TME dual responsive SA-FeGdNP-DOX@mPEG significantly enhanced the contrast of MR images between tumors and livers, and the ΔSNR difference reached 501%. In addition, our SA-FeGdNP-DOX2@mPEG2 with tumor targetability and controlled DOX release responding to the TME was also used for tumor-specific chemotherapy with reduced side effects.