Monitoring ROS Responsive Fe3O4-based Nanoparticle Mediated Ferroptosis and Immunotherapy via 129Xe MRI.

The immune checkpoint blockade strategy has improved the survival rate of late-stage lung cancer patients. However, the low immune response rate limits the immunotherapy efficiency. Here, we report a ROS-responsive Fe3O4-based nanoparticle that undergoes charge reversal and disassembly in the tumor microenvironment, enhancing the uptake of Fe3O4 by tumor cells and triggering a more severe ferroptosis. In the tumor microenvironment, the nanoparticle rapidly disassembles and releases the loaded GOx and the immune-activating peptide Tuftsin under overexpressed H2O2. GOx can consume the glucose of tumor cells and generate more H2O2, promoting the disassembly of the nanoparticle and drug release, thereby enhancing the therapeutic effect of ferroptosis. Combined with Tuftsin, it can more effectively reverse the immune-suppressive microenvironment and promote the recruitment of effector T cells in tumor tissues. Ultimately, in combination with α-PD-L1, there is significant inhibition of the growth of lung metastases. Additionally, the hyperpolarized 129Xe method has been used to evaluate the Fe3O4 nanoparticle-mediated immunotherapy, where the ventilation defects in lung metastases have been significantly improved with complete lung structure and function recovered. The ferroptosis-enhanced immunotherapy combined with non-radiation evaluation methodology paves a new way for designing novel theranostic agents for cancer therapy.

One-Pot Assembly of Dual-Site-Specific Antibody-Drug Conjugates via Glycan Remodeling and Affinity-Directed Traceless Conjugation.

The drug-to-antibody ratio (DAR) value and dual-drug combination greatly influence the therapeutic index of antibody-drug conjugates (ADCs). The reported approaches usually require multifunctional branched linkers, a combination of complicated technologies, or protein-protein ligation, which may incorporate multihydrophobic fragments or result in low coupling efficiency. Herein, we developed a facile and efficient one-pot method to assemble dual-site-specific ADCs with defined DARs at both the N-glycosylation site and K248 site, either with the same payloads or with two types of payloads. The constructed dual-site ADCs showed acceptable homogeneity, excellent buffer stability, and enhanced in vitro and in vivo efficiency.

Synthesis of symmetrical secondary oligoethylene glycolated amines from diethanolamine.

Monodisperse oligoethylene glycols (M-OEGs)-containing symmetrical secondary amines are highly valuable synthetic intermediates in drug development and materials sciences. Scalable three-step synthesis of M-OEGs secondary amines with flexible M-OEGs and/or alkyl chains is described herein. Through reduction amination of diethanolamine, Williamson ether synthesis, and subsequent deprotection, a series of M-OEGs secondary amines with diverse and fine-tunable chemical structures were conveniently prepared. The presented strategy is attractive with readily available starting materials, simple catalytic systems, scalable synthesis, and avoids the use of explosive sodium azide.

Synthesis of trifluoromethylated aza-BODIPYs as fluorescence-19F MRI dual imaging and photodynamic agents.

Dual-imaging agents with highly sensitive fluorescence (FL) imaging and highly selective fluorine-19 magnetic resonance imaging (19F MRI) are valuable for biomedical research. At the same time, photosensitizers with a high reactive oxygen species (ROS) generating capability are crucial for photodynamic therapy (PDT) of cancer. Herein, a series of tetra-trifluoromethylated aza-boron dipyrromethenes (aza-BODIPYs) were conveniently synthesized from readily available building blocks and their physicochemical properties, including ultraviolet-visible (UV-Vis) absorption, FL emission, photothermal efficacy, ROS generating efficacy, and 19F MRI sensitivity, were systematically investigated. An aza-BODIPY with 12 symmetrical fluorines was identified as a potent FL-19F MRI dual-imaging traceable photodynamic agent. It was found that the selective introduction of trifluoromethyl (CF3) groups into aza-BODIPYs may considerably improve their UV absorption, FL emission, photothermal efficacy, and ROS generating properties, which lays the foundation for the rational design of trifluoromethylated aza-BODIPYs in biomedical applications.

Hydrofluorocarbon nanoparticles for 19F MRI-fluorescence dual imaging and chemo-photodynamic therapy.

The synergistic chemotherapy and photodynamic therapy (PDT) may significantly improve the cancer therapeutic efficacy, in which fluorinated nanoemulsions are highly advantageous for their ability to deliver oxygen to hypoxic tumors and provide fluorine-19 magnetic resonance imaging (19F MRI). The low solubility of chemotherapy drugs and photosensitizers in current perfluorocarbon (PFC)-based 19F MRI agents usually leads to complicated formulations or chemical modifications and low nanoemulsion stability and performance. Herein, we employ readily available partially fluorinated ethyl 2-(3,5-bis(trifluoromethyl)phenyl)acetate as the 19F MRI agent and the solvent to dissolve the cancer stem cell inhibitor salinomycin and the photosensitizer ICG for the convenient preparation of 19F MRI-fluorescence dual imaging and synergistic chemotherapy, photothermal and photodynamic therapy nanoemulsions. The chemotherapy drug salinomycin has a high solubility in the partially fluorinated reagent, facilitating its high loading and efficient delivery. Paramagnetic iron(III) (Fe3+) is incorporated into the nanoemulsion through the dissolved chelator to significantly improve the 19F MRI sensitivity. Furthermore, the dissolved fluorinated 2-pyridone enables the efficient capture and sustained release of singlet oxygen in the dark for high PDT efficacy. The multifunctional nanoemulsions show sensitive 19F MRI and fluorescence dual imaging capability and high synergistic chemotherapy, photothermal and photodynamic therapy efficacy in cancer cells, which may be valuable oxygen delivery, sustained ROS generating and release, dual imaging and multimodal therapy agents for hypoxic tumors. This study provided a convenient co-solubilization strategy for the rapid construction of multifunctional theranostics for hypoxic tumors.

In Vivo Nitroreductase Imaging via Fluorescence and Chemical Shift Dependent 19 F NMR.

Nitroreductase (NTR) is an important biomarker widely used to evaluate the degree of tumor hypoxia. Although a few optical methods have been reported for detecting nitroreductase at low concentration ranges, an effective strategy for nitroreductase monitoring in vivo without limits to the imaging depth is still lacking. Herein, a novel dual-mode NIR fluorescence and 19 F MRI agent, FCy7-NO2 , is proposed for imaging tumor hypoxia. We show that FCy7-NO2 serves as not only a rapid NIR fluorescence enhanced probe for monitoring and bioimaging of nitroreductase in tumors, but also a novel 19 F MR chemical shift-sensitive contrast agent for selectively detecting nitroreductase catalyzed reduction. Notably, integrating two complementary imaging technologies into FCy7-NO2 enables sensitive detection of nitroreductase in a broad concentration range without tissue-depth limit. In general, this agent has a remarkable response to nitroreductase, which provides a promising method for understanding tumor evolution and its physiological role in the hypoxic microenvironment.

Prediction of postpartum hemorrhage in pregnant women with immune thrombocytopenia: Development and validation of the MONITOR model in a nationwide multicenter study.

Globally, postpartum hemorrhage (PPH) is the leading cause of maternal death. Women with immune thrombocytopenia (ITP) are at increased risk of developing PPH. Early identification of PPH helps to prevent adverse outcomes, but is underused because clinicians do not have a tool to predict PPH for women with ITP. We therefore conducted a nationwide multicenter retrospective study to develop and validate a prediction model of PPH in patients with ITP. We included 432 pregnant women (677 pregnancies) with primary ITP from 18 academic tertiary centers in China from January 2008 to August 2018. A total of 157 (23.2%) pregnancies experienced PPH. The derivation cohort included 450 pregnancies. For the validation cohort, we included 117 pregnancies in the temporal validation cohort and 110 pregnancies in the geographical validation cohort. We assessed 25 clinical parameters as candidate predictors and used multivariable logistic regression to develop our prediction model. The final model included seven variables and was named MONITOR (maternal complication, WHO bleeding score, antepartum platelet transfusion, placental abnormalities, platelet count, previous uterine surgery, and primiparity). We established an easy-to-use risk heatmap and risk score of PPH based on the seven risk factors. We externally validated this model using both a temporal validation cohort and a geographical validation cohort. The MONITOR model had an AUC of 0.868 (95% CI 0.828-0.909) in internal validation, 0.869 (95% CI 0.802-0.937) in the temporal validation, and 0.811 (95% CI 0.713-0.908) in the geographical validation. Calibration plots demonstrated good agreement between MONITOR-predicted probability and actual observation in both internal validation and external validation. Therefore, we developed and validated a very accurate prediction model for PPH. We hope that the model will contribute to more precise clinical care, decreased adverse outcomes, and better health care resource allocation.

Dysregulation of LncRNA ANRIL mediated by miR-411-3p inhibits the malignant proliferation and tumor stem cell like property of multiple myeloma via hypoxia-inducible factor 1α.

Long non-coding RNA (lncRNA) ANRIL has been reported to be closely related to the relapse of multiple myeloma patients. However, the functional role and underlying mechanism of lncRNA ANRIL in multiple myeloma are not known. This study aims to investigate the biological function of lncRNA ANRIL in multiple myeloma. In this study, compared with normal tissues from healthy donors, lncRNA ANRIL and HIF-1α expressions were up-regulated in tumor tissues from multiple myeloma patients. miR-411-3p expression was down-regulated in tumor tissues from multiple myeloma patients. Besides, lncRNA ANRIL can interact with miR-411-3p. HIF-1α was confirmed to be a target of miR-411-3p. Correlation analysis showed that lncRNA ANRIL expression was negatively correlated with miR-411-3p expression. HIF-1α expression was negatively correlated with miR-411-3p expression. Further transfection experiments showed that knockdown of ANRIL or overexpression of miR-411-3p significantly inhibited cell proliferation, tumor formation ability and tumor stem cell like property, promoted cell apoptosis in vitro. Finally, miR-411-3p mimic reduced tumor volume, improved survival rate, suppressed malignant proliferation and tumor stem cell like property in U266 xenograft model. Our results demonstrate that lncRNA ANRIL mediated by miR-411-3p promotes the malignant proliferation and tumor stem cell like property of multiple myeloma through regulating HIF-1α.

Development and validation of a prediction model (AHC) for early identification of refractory thrombotic thrombocytopenic purpura using nationally representative data.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening haematological emergency. Although therapeutic plasma exchange together with corticosteroids achieve successful outcomes, a considerable number of patients remain refractory to this treatment and require early initiation of intensive therapy. However, a method for the early identification of refractory iTTP is not available. To develop and validate a model for predicting the probability of refractory iTTP, a cohort of 265 consecutive iTTP patients from 17 large medical centres was retrospectively identified. The derivation cohort included 94 patients from 11 medical centres. For the validation cohort, we included 40 patients from the other six medical centres using geographical validation. An easy-to-use risk score system was generated, and its performance was assessed using internal and external validation cohorts. In the multivariable logistic analysis of the derivation cohort, three candidate predictors were entered into the final prediction model: age, haemoglobin and creatinine. The prediction model had an area under the curve of 0.886 (95% CI: 0.679-0.974) in the internal validation cohort and 0.862 (95% CI: 0.625-0.999) in the external validation cohort. The calibration plots showed a high agreement between the predicted and observed outcomes. In conclusion, we developed and validated a highly accurate prediction model for the early identification of refractory iTTP. It has the potential to guide tailored therapy and is a step towards more personalized medicine.

Monodisperse and Polydisperse PEGylation of Peptides and Proteins: A Comparative Study.

Although PEGylation is widely used in biomedicine with great success, it suffers from many drawbacks, such as polydispersity, nonbiodegradability, and loss of precursor potency. Recently, the search for polyethylene glycol (PEG) substitutes has attracted considerable attention. Some of the substitutes partially address the drawbacks of PEGs, but sacrifice the "stealth" effect of PEGs and bring in new issues. Herein, we developed monodisperse oligoethylene glycol (M-OEG) polyamides over 5000 Da as biodegradable and monodisperse PEGylation (M-PEGylation) agents, which provided M-PEGylated peptides and proteins with high monodispersity and a biodegradable PEG moiety. Compared to regular PEGylated proteins with a complex "stealth" cloud of PEG, the hydrogen bond interactions between the M-OEG polyamides and proteins provided the M-PEGylated protein with a biodegradable "stealth" cloak. The monodisperse and biodegradable M-PEGylation strategy as well as the peculiar protein-M-OEG polyamide interactions may shed light on many long-lasting issues during the development of PEGylated biologic drugs, such as monodispersity, biodegradability, and tunable conformation.

Quantitatively Fine-Tuning the Physicochemical and Biological Properties of Peptidic Polymers through Monodisperse PEGylation.

In biomedicine, PEGylation is one of the most successful strategies to modify the physicochemical and biological properties of peptides, proteins, and other biomacromolecules. Because of the polydisperse nature of regular PEGs and limited PEGylation strategies, it is challenging to quantitatively fine-tune and accurately predict the properties of biomacromolecules after PEGylation. However, such fine-tuning and prediction may be crucial for their biomedical applications. Herein, some monodisperse PEGylation strategies, including backbone PEGylation, side-chain PEGylation, and highly branched PEGylation, have been developed. In a comparative fashion, the impact of PEGylation strategies and monodisperse PEG sizes on the physicochemical and biological properties, including lipophilicity, thermosensitivity, biocompatibility, plasma stability, and drug delivery capability, of peptidic polymers has been quantitatively studied. It was found that the physicochemical and biological properties of PEGylated peptidic polymers can be quantitatively fine-tuned and accurately predicted through these monodisperse PEGylation strategies. After the comparative study, a side-chain monodisperse PEGylated peptidic polymer was chosen as fluorine-19 magnetic resonance and fluorescence dual-imaging traceable drug delivery vehicle. Our study may not only promote the transformation of PEGylation from an empirical technology to a quantitative science but also shed light on the rational design of PEGylated biomaterials and pharmaceutics.

F--Free Deoxyhydrotrifluoromethylation of α-Keto Esters with Ph3P+CF2CO2-: Synthesis of α-CF3-Substituted Esters.

Trifluoromethylated compounds are usually obtained via trifluoromethylation reaction by the use of CF3SiMe3 and NaSO2CF3, Umemoto's and Togni's reagents. Here, an external fluorine anion-free direct deoxyhydrotrifluoromethylation of α-keto esters with a difluoromethylating reagent has been achieved, in which the employment of water can promote the dissociation of the CF2 group to form a CF3 moiety, which provides the successful transformation. The current protocol demonstrates one of the most practical approaches to generate α-trifluoromethyl esters with a broad substrate scope and high functional group compatibility, in which it is applicable to late-stage modification of biologically active compounds and can be readily scaled up. Mechanistic investigation reveals that an in situ-generated gem-difluoroalkene intermediate is decomposed by water, giving rise to acid fluoride and HF.

Synthesis of Branched Monodisperse Oligoethylene Glycols and 19F MRI-Traceable Biomaterials through Reductive Dimerization of Azides.

Multifunctionalized and branched M-OEGs represent valuable PEGylation agents, linkers, and scaffolds in biomedicine. However, the tedious synthesis limited their availability and application. We herein present an azide reductive dimerization method for the convenient synthesis of aza-M-OEGs and derivatives, which provides easy access to a variety of multifunctionalized and branched M-OEGs in one step. With this method, hexa-arm M-OEGs with 54 symmetrical fluorines were synthesized in two steps as a water-soluble, self-assemble, 19F MRI sensitive, and biocompatible dendritic biomaterial.

A Chemical Strategy for Amphiphile Replacement in Membrane Protein Research.

Membrane mimics are indispensable tools in the structural and functional understanding of membrane proteins (MPs). Given stringent requirements of integral MP manipulations, amphiphile replacement is often required in sample preparation for various biophysical purposes. Current protocols generally rely on physical methodologies and rarely reach complete replacement. In comparison, we report herein a chemical alternative that facilitates the exhaustive exchange of membrane-mimicking systems for MP reconstitution. This method, named sacrifice-replacement strategy, was enabled by a class of chemically cleavable detergents (CCDs), derived from the disulfide incorporation in the traditional detergent n-dodecyl-ß-d-maltopyranoside. The representative CCD behaved well in both solubilizing the diverse α-helical human G protein-coupled receptors and refolding of the ß-barrel bacterial outer membrane protein X, and more importantly, it could also be readily degraded under mild conditions. By this means, the A2A adenosine receptor was successfully reconstituted into a series of commercial detergents for stabilization screening and nanodiscs for electron microscopy analysis. Featured by the simplicity and compatibility, this CCD-mediated strategy would later find more applications when being integrated in other biophysics studies.

Peptidic Monodisperse PEG "combs" with Fine-Tunable LCST and Multiple Imaging Modalities.

Thermosensitive and imaging-traceable materials with fine-tunable lower critical solution temperature (LCST) around body temperature are highly valuable in biomedicine. However, such materials are rare because it is challenging to fine-tune the LCST and incorporate suitable imaging modalities. Herein, peptidic monodisperse polyethylene glycol (M-PEG) "combs" with fine-tunable LCST, "hot spot" fluorine-19 magnetic resonance imaging (19F MRI), thermoresponsive fluorescent imaging, and drug loading ability were developed through accurately programming their structures during solid phase peptide synthesis (SPPS). The easy availability, structural accuracy, biocompatibility, and versatility provide the M-PEG "combs" with promising prospects as thermoresponsive and imaging-traceable biomaterials for controlled drug delivery.

Monodisperse oligoethylene glycols modified Camptothecin, 10-Hydroxycamptothecin and SN38 prodrugs.

Camptothecin, which represents a class of natural products with high anticancer activity, suffers low water solubility which hampers its clinic application. To address this issue, monodisperse polyethylene glycols were employed to modify this class of natural products, including Camptothecin, 10-Hydroxycamptothecin, and SN38. Through selective modification with a series of monodisperse polyethylene glycols, 31 Camptothecin derivatives, including 9 ethers and 22 carbonates, were prepared using a macrocyclic sulfate-based strategy with high efficacy. Monodisperse polyethylene glycols modification provided the Camptothecin derivatives with high purity and fine-tunable water solubility. Through the physicochemical and biological assays, a few novel prodrugs with good solubility, cytotoxicity, and valuable drug release profile were identified as promising anticancer drug candidates.

The IRF9-SIRT1-P53 axis is involved in the growth of human acute myeloid leukemia.

Acute myeloid leukemia (AML) is a highly heterogeneous disease, with biologically and prognostically different subtypes. Although a growing number of distinct AML subsets have been increasingly characterized, patient management has remained disappointingly uniform. The molecular mechanism underlying AML needs to be further investigated. Here we identify IRF9 as a negative regulator of human AML. We show that IRF9 mRNA and protein levels are down-regulated in human AML samples compared with samples from healthy donors. IRF9 knockdown promotes proliferation, colony formation and survival of OCI/AML-2 and OCI/AML-3 cells, whereas IRF9 overexpression obtains oppose results. Mechanism analysis shows that IRF9 binds SIRT1 promoter and represses SIRT1 expression in OCI/AML-2 and OCI/AML-3 cells. In AML samples, the expression of SIRT1 is up-regulated and negatively correlated with IRF9 level. IRF9 also increases the acetylation of p53, a deacetylation substrate of SIRT1, and promotes the expression of p53 target genes. Knockdown of p53 blocks the effects of IRF9 on cell survival and growth in vitro. These findings provide evidence that IRF9 serves as an important regulator in human AML by repressing SIRT1-p53 pathway and that IRF9 may be a potential target for AML treatment.

Study of kinetics of 19F-MRI using a fluorinated imaging agent (19FIT) on a 3T clinical MRI system.

PURPOSE: To use 19F imaging tracer (19FIT-27) to evaluate kinetics in major organs. INTRODUCTION: Kinetics studies using proton MRI are difficult because of low concentration of 19FIT-27 protons relative to background water protons. Because there is no background source of 19F NMR in a biological body, 19F may be an ideal nucleus to directly trace 19FIT-27. However, there are several challenges for reliable 19F MR imaging and spectroscopy, particularly with clinical whole-body MRI systems, which include low concentrations and long 19F T1. METHODS AND MATERIALS: We performed a dynamic 19F MRI study on mice at a 3T whole-body MRI system using a homemade transmit/receive (Tx/Rx) switch and a Tx/Rx volume RF coil. We used a newly developed fluorine imaging agent, which has 27 identical fluorine atoms with identical chemical shift, a relatively short T1, and high hydrophilicity. Basic kinetics parameters were estimated from the 19F signal-time curve. RESULTS AND DISCUSSIONS: Resultant fluorine images show fairly high spatial (3 × 3 × 3 mm3) and temporal resolutions. Biodistribution and kinetics of 19FIT-27 are obtained via 19F images for major uptake organs. CONCLUSIONS: Whole-body dynamic 19F MRI of newly developed 19FIT-27 in mice was obtained with fairly high spatial and temporal resolutions on a 3T clinical MRI system. The present study demonstrates the feasibility of 19F MRI using our newly developed compound to investigate major organ kinetics.

Monitoring dendrimer conformational transition using 19 F and 1 H2 O NMR.

The conformational transition of a fluorinated amphiphilic dendrimer is monitored by the 1 H signal from water, alongside the 19 F signal from the dendrimer. High-field NMR data (chemical shift δ, self-diffusion coefficient D, longitudinal relaxation rate R1 , and transverse relaxation rate R2 ) for both dendrimer (19 F) and water (1 H) match each other in detecting the conformational transition. Among all parameters for both nuclei, the water proton transverse-relaxation rate R2 (1 H2 O) displays the highest relative scale of change upon conformational transition of the dendrimer. Hydrogen/deuterium-exchange mass spectrometry reveals that the compact form of the dendrimer has slower proton exchange with water than the extended form. This result suggests that the sensitivity of R2 (1 H2 O) toward dendrimer conformation originates, at least partially, from the difference in proton exchange efficiency between different dendrimer conformations. Finally, we also demonstrated that this conformational transition could be conveniently monitored using a low-field benchtop NMR spectrometer via R2 (1 H2 O). The 1 H2 O signal thus offers a simple way to monitor structural changes of macromolecules using benchtop time-domain NMR.

Fe2O3-Promoted Intermolecular Chlorotrifluoromethylthiolation of Alkenes.

A simple, convenient method for intermolecular chlorotrifluoromethylthiolation of alkenes by using a low-cost and more abundant iron catalyst has been developed. This protocol provides a straightforward way to synthesize a variety of useful SCF3-containing chlorides from a wide range of alkenes, including electron-deficient, aromatic, and unactivated alkenes. Mechanistic studies indicate that this is a free radical transformation, and the stronger electrophilic trifluoromethylthiolating reagent CF3SCl was generated in situ under the employed conditions. The synthetic applications of this approach were also explored by a variety of synthetically useful transformations.