Visible-Light-Driven Iron-Catalyzed 1,2-Difluoroalkylthiolation of Alkenes.

The synthesis of medicinally interesting aryldifluoromethylated compounds has drawn significant research attention in recent years. Herein, we report an unprecedented iron-mediated process for the selective defluorination of trifluoromethylarenes to achieve the 1,2-difluoroalkylthiolation of alkenes. Preliminary mechanistic studies revealed that thiolate anion, trifluoromethylarene, and iron cation could form an electron donor-acceptor (EDA) complex, which induced selective defluorination and then difunctionalization of alkenes to obtain aryldifluoromethylated products. The generated aryldifluoromethylated compounds make it difficult to form an EDA complex again, thus avoiding excessive defluorination. This conversion has concise and ambient reaction conditions and provides an alternative solution for obtaining difluorobenzylic intermediates.

Design of Selective PARP-1 Inhibitors and Antitumor Studies.

Designing selective PARP-1 inhibitors has become a new strategy for anticancer drug development. By sequence comparison of PARP-1 and PARP-2, we identified a possible selective site (S site) consisting of several different amino acid residues of α-5 helix and D-loop. Targeting this S site, 140 compounds were designed, synthesized, and characterized for their anticancer activities and mechanisms. Compound I16 showed the highest PARP-1 enzyme inhibitory activity (IC50 = 12.38 ± 1.33 nM) and optimal selectivity index over PARP-2 (SI = 155.74). Oral administration of I16 (25 mg/kg) showed high inhibition rates of Hela and SK-OV-3 tumor cell xenograft models, both of which were higher than those of the oral positive drug Olaparib (50 mg/kg). In addition, I16 has an excellent safety profile, without significant toxicity at high oral doses. These findings provide a novel design strategy and chemotype for the development of safe, efficient, and highly selective PARP-1 inhibitors.

Immunopeptidome mining reveals a novel ERS-induced target in T1D.

Autoreactive CD8+ T cells play a key role in type 1 diabetes (T1D), but the antigen spectrum that activates autoreactive CD8+ T cells remains unclear. Endoplasmic reticulum stress (ERS) has been implicated in ß-cell autoantigen generation. Here, we analyzed the major histocompatibility complex class I (MHC-I)-associated immunopeptidome (MIP) of islet ß-cells under steady and ERS conditions and found that ERS reshaped the MIP of ß-cells and promoted the MHC-I presentation of a panel of conventional self-peptides. Among them, OTUB258-66 showed immunodominance, and the corresponding autoreactive CD8+ T cells were diabetogenic in nonobese diabetic (NOD) mice. High glucose intake upregulated pancreatic OTUB2 expression and amplified the OTUB258-66-specific CD8+ T-cell response in NOD mice. Repeated OTUB258-66 administration significantly reduced the incidence of T1D in NOD mice. Interestingly, peripheral blood mononuclear cells (PBMCs) from patients with T1D, but not from healthy controls, showed a positive IFN-γ response to human OTUB2 peptides. This study provides not only a new explanation for the role of ERS in promoting ß-cell-targeted autoimmunity but also a potential target for the prevention and treatment of T1D. The data are available via ProteomeXchange with the identifier PXD041227.

Small Molecule SHP2 Inhibitor LXQ-217 Affects Lung Cancer Cell Proliferation in Vitro and in Vivo.

BACKGROUND: SHP2 is highly expressed in a variety of cancer and has emerged as a potential target for cancer therapeutic agents. The identification of uncharged pTyr mimics is an important direction for the development of SHP2 orthosteric inhibitors. METHODS: Surface plasmon resonance analysis and cellular thermal shift assay were employed to verify the direct binding of LXQ-217 to SHP2. The inhibitory effect of LXQ-217 was characterized by linear Weaver-Burke enzyme kinetic analysis and BIOVIA Discovery Studio. The inhibition of tumor cell proliferation by LXQ-217 was characterized by cell viability assay, colony formation assays and hoechst 33258 staining. The inhibition of lung cancer proliferation in vivo was studied in nude mice after oral administration of LXQ-217. RESULTS: An electroneutral bromophenol derivative, LXQ-217, was identified as a competitive SHP2 inhibitor. LXQ-217 induced apoptosis and inhibited growth of human pulmonary epithelial cells by affecting the RAS-ERK and PI3 K-AKT signaling pathways. Long-term oral administration of LXQ-217 significantly inhibited the proliferation ability of lung cancer cells in nude mice. Moreover, mice administered LXQ-217 orally at high doses exhibited no mortality or significant changes in vital signs. CONCLUSIONS: Our findings on the uncharged orthosteric inhibitor provide a foundation for further development of a safe and effective anti-lung cancer drug.

Advances in Development of Selective Antitumor Inhibitors That Target PARP-1.

Cancer is a major threat to the lives and health of people around the world, and the development of effective antitumor drugs that exhibit fewer toxic effects is an important aspect of cancer treatment. PARP inhibitors are antitumor drugs that target pathways involved in DNA-damage repair. The currently approved PARP inhibitors include olaparib, niraparib, rucaparib, talazoparib, fuzuloparib, and pamiparib. Hematological toxicities associated with the simultaneous inhibition of PARP-1 and PARP-2 have limited the clinical applications of these drugs. The present review introduces the necessity for research on the development of selective PARP-1 inhibitors from the perspective of structural and functional mechanisms of PARP-1 inhibition. A review of recently reported selective PARP-1 inhibitors provides the foundation for exploring novel strategies for designing selective PARP-1 inhibitors from the perspective of structure-activity relationships combined with computer simulations.

[Analysis of the clinical effect of percutaneous pedicle screw fixation combined with transpedicular bone grafting in the treatment of thoracolumbar fracture].

OBJECTIVE: To investigate the clinical efficacy of percutaneous screw fixation combined with minimally invasive transpedicular bone grafting and non-bone grafting in the treatment of thoracolumbar fractures. METHODS: From Janury 2021 to June 2022, 40 patients with thoracolumbar fracture were divided into the experimental group and the control group. There were 26 patients in the experimental group, including 21 males and 5 females with an aberage age of (47.3±12.3) years old, who underwent percutaneous pedicle screw fixation combined with transpedicular autogenous bone grafting. In the control group, 14 patients received percutaneous pedicle screw fixation only. including 7 makes and 7 females with an average age of (50.2±11.2) years old. The operative time, intraoperative blood loss, anterior height ratio of injured vertebrae, Cobb angle, visual analogue score (VAS), MacNab scores, loosening or broken of the implants. were compared and analyzed. RESULTS: There was no significant difference in operation time, intraoperative blood loss, VAS and anterior height ratio of injured vertebrae between the two groups. Compared with the preoperative results, VAS and anterior height ratio of injured vertebrae were improved statistically(P<0.05). For Cobb angle of injured vertebra, there was no significant difference between the two groups before surgery (P=0.766). While at 1 week, 3 months and 12 months after surgery, there were statistically differences between the two groups (P values were 0.042, 0.007 and 0.039, respectively). The Cobb angle of injured vertebrae one year after operation was statistically decreased in both groups compared with that before surgery (P<0.001). One year after surgery, the excellent and good rate of Macnab scores was 96.15% in the experimental group and 92.86% in the control group, and there was no statistical differences between the two groups (P=0.648). There was one patient in the control group suffering superficial wound infection on the third day, which was cured by dressing change and anti-infection treatment. There were no postoperative screw loosening and broken in both groups. CONCLUSION: The two surgical methods have the advantages of less trauma, less pain and quicker recovery, which can restore the height of the injured vertebra, reconstruct the spinal sequence and reduce the fracture of the vertebral body. Transpedicular autogenous bone grafting can increase the stability of the fractured vertebra and maintain the height of the vertebra better after surgery, thus reducing the possibility of complications such as kyphosis, screw loosening and broken.

MNK, mTOR or eIF4E-selecting the best anti-tumor target for blocking translation initiation.

Overexpression of eIF4E is common in patients with various solid tumors and hematologic cancers. As a potential anti-cancer target, eIF4E has attracted extensive attention from researchers. At the same time, mTOR kinases inhibitors and MNK kinases inhibitors, which are directly related to regulation of eIF4E, have been rapidly developed. To explore the optimal anti-cancer targets among MNK, mTOR, and eIF4E, this review provides a detailed classification and description of the anti-cancer activities of promising compounds. In addition, the structures and activities of some dual-target inhibitors are briefly described. By analyzing the different characteristics of the inhibitors, it can be concluded that MNK1/2 and eIF4E/eIF4G interaction inhibitors are superior to mTOR inhibitors. Simultaneous inhibition of MNK and eIF4E/eIF4G interaction may be the most promising anti-cancer method for targeting translation initiation.

Nickel-catalyzed stereoselective reductive cross-coupling of gem-difluoroalkenes with alkenyl electrophiles.

Herein we develop a Ni-catalyzed defluorinative cross-electrophile coupling of gem-difluoroalkenes with alkenyl electrophiles that allowed the generation of C(sp2)-C(sp2) bonds. The reaction provided various monofluoro 1,3-dienes with broad functional group compatibility and excellent stereoselectivity. Synthetic transformations and applications to the modification of complex compounds were also demonstrated.

Proteomic identification of MHC class I-associated peptidome derived from non-obese diabetic mouse thymus and pancreas.

The peptides repertoire presented to CD8+ T cells by major histocompatibility complex (MHC) class I molecules is referred to as the MHC I-associated peptidome (MIP), which regulates thymus development, peripheral survival and function during lifetime of CD8+ T cells. Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by pancreatic ß cells destruction mediated primarily by autoreactive CD8+ T cells. Non-obese diabetic (NOD) mouse is an important animal model of T1D. Here, we deeply analyzed the MIP derived from NOD mice thymus and pancreas, and demonstrated that the thymus MIP source proteins partially shared with the MIP source proteins derived from NOD mice pancreas and ß cell line. One H-2Kd restricted peptide SLC35B126-34 which was shared by MIP derived from both NOD mice pancreatic tissues and islet ß-cell line, but absent in MIP from NOD thymus tissues, showed ability to stimulate IFN-γ secretion and proliferation of NOD mice splenic CD8+ T cells. The global view of the MHC I-associated self-peptides repertoire in the thymus and pancreas of NOD mice may serve as a biological reference to identify potential autoantigens targeted by autoreactive CD8+ T cells in T1D. Data are available via ProteomeXchange with identifier PXD031966. SIGNIFICANCE: The peptides repertoire presented to CD8+ T cells by major histocompatibility complex (MHC) class I molecules is referred to as the MHC I-associated peptidome (MIP). The MIP presented by thymic antigen presenting cells (APCs) is crucial for shaping CD8+ T cell repertoire and self-tolerance, while the MIP presented by peripheral tissues and organs is not only involved in maintaining periphery CD8+ T cell survival and homeostasis, but also mediates immune surveillance and autoimmune responses of CD8+ T cells under pathological conditions. Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by the destruction of pancreatic ß cells, mediated primarily by autoreactive CD8+ T cells. Non-obese diabetic (NOD) mouse is one of important animal models of spontaneous autoimmune diabetes that shares several key features with human T1D. The global view of the MHC I-associated self-peptides repertoire in the thymus and pancreas of NOD mice may serve as a good biological reference to identify potential autoantigens targeted by autoreactive CD8+ T cells in T1D. It has great significance for further clarifying the immune recognition and effect mechanism of autoreactive CD8+ T cells in the pathogenesis of T1D, and then developing antigen-specific immune intervention strategies.

An acetate-independent pathway for isopropanol production via HMG-CoA in Escherichia coli.

Isopropanol has a good potential as a new fuel substitution. In the model biosynthesis pathway of isopropanol synthesis, acetoacetyl-CoA is converted to acetoacetate by acetoacetyl-CoA transferases, which requires an acetate molecule as a substrate. Herein, a novel isopropanol synthesis pathway based on mammalian ketone metabolic pathway was developed. In this pathway, acetoacetyl-CoA is condensed with acetyl-CoA to generate 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) by HMG-CoA synthase, and then catalyzed by HMG-CoA lyase to generate acetoacetate. This process is acetate-independent. Under the same experimental system using glycerol as carbon source, the E. coli strain MG::ISOP1 containing the novel pathway produced 11.7 times more isopropanol than the strain MG::ISOP0 containing the model pathway. The pta-ackA knockout mutant strain MG∆pta-ackA::ISOP1, which reduced the conversion of acetyl-CoA to acetate, further increased the production from 76 mg/L to 360 mg/L. In another strategy, knocking out atoDA to block the acetoacetate degradation pathway in strain MG∆atoDA::ISOP1 increased the production to 680 mg/L. By knocking out both of pta-ackA and atoDA, strain MGΔpta-ackAΔatoDA::ISOP1 produced 964 mg/L of isopropanol, which was 12.7 times that of MG::ISOP1. This study indicated that the novel pathway is competent for isopropanol synthesis, and provides a new perspective for biosynthesis of isopropanol.

Lichen Amyloidosis on the Scalp: A Case Report.

Lichen amyloidosis (LA) is one form of primary cutaneous amyloidosis, presented as discrete, lichenoid papules with itching, commonly involving the extensor surfaces of extremities. Scalp involvement is rarely reported in the literature. In this study, we reported a case of LA over the crown and vertex areas of the scalp. The lesions subsided with topical clobetasol propionate/all-trans retinoic acid compound ointment treatment for 2 months and achieved significant improvement.

Toward a Treatment of Cancer: Design and In Vitro/In Vivo Evaluation of Uncharged Pyrazoline Derivatives as a Series of Novel SHP2 Inhibitors.

Src homology 2 domain-containing protein tyrosine phosphatase 2 (SHP2) is a non-receptor protein tyrosine phosphatase (PTP) encoded by the PTPN11 gene, which is involved in the RAS/MAPK cell signaling transduction process. SHP2 has been shown to contribute to the progression of various cancers and is emerging as an important target for anti-tumor drug research. However, past efforts to develop SHP2 inhibitors into drugs have been unsuccessful owing to the positively charged nature of the active site pocket tending to bind negatively charged groups that are usually non-drug-like. Here, a series of uncharged pyrazoline derivatives were designed and developed as new SHP2 inhibitors using a structure-based strategy. Compound 4o, which exhibited the strongest SHP2 inhibitory activity, bound directly to the catalytic domain of SHP2 in a competitive manner through multiple hydrogen bonds. Compound 4o affected the RAS/MAPK signaling pathway by inhibiting SHP2, and subsequently induced apoptosis and growth inhibition of HCT116 cells in vitro and in vivo. Notably, the oral administration of compound 4o in large doses showed no obvious toxicity. In summary, our findings provide a basis for the further development of compound 4o as a safe, effective and anti-tumor SHP2 inhibitor.

Nickel-Catalyzed Arylation of C(sp3)-O Bonds in Allylic Alkyl Ethers with Organoboron Compounds.

A nickel-catalyzed cross-coupling of allylic alkyl ethers with organoboron compounds through the cleavage of the inert C(sp3)-O(alkyl) bonds is described. Several types of allylic alkyl ethers can be coupled with various boronic acids or their derivatives to give the corresponding products in good to excellent yields with wide functional group tolerance and excellent regioselectivity. The gram-scale reaction and late-stage modification of biologically active compounds further prove the practicality of this synthetic method.

Sesquiterpenoids From the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11.

The fungal strains Pseudogymnoascus are a kind of psychrophilic pathogenic fungi that are ubiquitously distributed in Antarctica, while the studies of their secondary metabolites are infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11 led to the isolation of six new tremulane sesquiterpenoids pseudotremulanes A-F (1-6), combined with one known analog 11,12-epoxy-12ß-hydroxy-1-tremulen-5-one (7), and five known steroids (8-12). The absolute configurations of the new compounds (1-6) were elucidated by their ECD spectra and ECD calculations. Compounds 1-7 were proved to be isomeride structures with the same chemical formula. Compounds 1/2, 3/4, 1/4, and 2/3 were identified as four pairs of epimerides at the locations of C-3, C-3, C-9, and C-9, respectively. Compounds 8 and 9 exhibited cytotoxic activities against human breast cancer (MDA-MB-231), colorectal cancer (HCT116), and hepatoma (HepG2) cell lines. Compounds 9 and 10 also showed antibacterial activities against marine fouling bacteria Aeromonas salmonicida. This is the first time to find terpenoids and steroids in the fungal genus Pseudogymnoascus.

A gas chromatography-flame ionization detection method for direct and rapid determination of small molecule volatile organic compounds in aqueous phase.

It is still difficult to directly detect low content of volatile organic compounds (VOCs) in water samples by gas chromatography (GC) because when water is the only solvent, it would result in the instability and poor repeatability of peak retention time and peak shape. The adverse effects of water on direct GC analysis of VOCs cannot be significantly reduced or eliminated by simply changing the detection condition of GC. However, it was found that the addition of methanol in samples to a certain final proportion, such as 50 or 75% (v/v), could greatly reduce or eliminate the adverse effects of water. By using 75% (v/v) methanol as a solvent, the standard curves of ethanol, acetic acid, acetone, and isopropanol with correlation coefficient (R 2) over 0.99 were successfully plotted by gas chromatography-flame ionization detection (GC-FID) in a certain concentration range, respectively. The results showed that the retention time and peak shape stability of ethanol, acetic acid, acetone, and isopropanol in aqueous solution were greatly improved by the addition of methanol to final concertation of 75% (v/v). To verify the practical application potential of this method, the method was applied to the detection of components in isopropanol fermentation wastewater. The results showed that the method has well applicability and reliability. The key points in the application of this method were also summarized. This GC analysis method would have a wider and better application prospect in the detection of water-soluble organic matters.

Near-infrared emission tracks inter-individual variability of carboxylesterase-2 via a novel molecular substrate.

A low-molecular-weight molecule (4-(2-(3-(dicyanomethyl)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)phenyl-benzoate, DDPB) has been developed. The organic framework possesses very weak fluorescence . The feasibility of the signal transduction has been performed via fluorometric titrations in solution. DDPB gives rise to responses to carboxylesterase 2 (CES2) based on "off-on" responses. The red emission at 670 nm has been derived from the enzyme-induced hydrolysis of ester linkages, thus suppressing the intramolecular charge transfer (ICT) effect and thereby generating the fluorescent segment. The optical excitation window for this probe is extended to the visible light range (λex = 516 nm), and it will induce less harmful influence on biological substances. The detection limit for the measurement of CES2 concentration is as low as 2.33 mU/mL. The conventional studies concerning the activation process are generally performed within only a single liveing cell system. In this study, it is the first time that expression of carboxylesterase 2 in five kinds of cell lines (HeLa > C1498 > active T cell > Jurkat > unactive T cell) has been clarified by flow cytometry, Western blotting, and confocal microscopy analysis. The elucidation of CES2 and its variability in a variety of cells will open new ways for drug metabolism and disease prevention. Graphical abstract We reported a new "substrate-mediated light-on" strategy based on an ester bond cleavage reaction. Most of prepared nanomaterials and organic fluorophores possessed short wavelength emissions in the blue or green region which will not be difficult for cellular imaging. In this study, a novel functional molecule (DDPB) was considered as the substrate for CES2 and the optical "off-on" response was realized. DDPB was cell permeable and possessed very low cytotoxicity. Moreover, the identification of CES2 and their subtle changes in five different cells afforded the sequence for carboxylesterase-2 as Hela > C1498 > Active T cell > Jurkat > Unactive T cell. Inhibition studies showed that the hydrolysis of DDPB was effectively suppressed by bis-p-nitrophenyl phosphate and the cellular tracking results firmly supported this point. To our knowledge, the inter-individual variability for the CES2 expressions in five different cell lines has never been reported via the substrate induced optical changes.

Inhibitor Binding Sites in the Protein Tyrosine Phosphatase SHP-2.

Protein tyrosine phosphatase 2 (SHP-2) has long been proposed as a cancer drug target. Several small-molecule compounds with different mechanisms of SHP-2 inhibition have been reported, but none are commercially available. Pool selectivity over protein tyrosine phosphatase 1 (SHP-1) and a lack of cellular activity have hindered the development of selective SHP-2 inhibitors. In this review, we describe the binding modes of existing inhibitors and SHP-2 binding sites, summarize the characteristics of the sites involved in selectivity, and identify the suitable groups for interaction with the binding sites.

Colorimetric Assay of Bacterial Pathogens Based on Co3O4 Magnetic Nanozymes Conjugated with Specific Fusion Phage Proteins and Magnetophoretic Chromatography.

It is important to detect pathogens rapidly, sensitively, and selectively for clinical medicine, homeland security, food safety, and environmental control. We report here a specific and sensitive colorimetric assay that incorporated a bovine serum albumin-templated Co3O4 magnetic nanozyme (Co3O4 MNE) with a novel specific fusion phage protein and magnetophoretic chromatography to detect Staphylococcus aureus. The Co3O4 MNE was conjugated to S. aureus-specific fusion-pVIII (Co3O4 MNE@fusion-pVIII), screened from the S. aureus-specific phage AQTFLGEQD (the phage monoclone is denoted by the peptide sequence). The as-prepared triple-functional Co3O4 MNE@fusion-pVIII particles were capable of capturing S. aureus in sterile milk, which were then isolated from milk magnetically. Assisted by polyethylene glycol, the Co3O4 MNE@fusion-pVIII@S. aureus complex was separated from the free Co3O4 MNE@fusion-pVIII by magnetophoretic chromatography in an external magnetic field. After transferring the isolated Co3O4 MNE@fusion-pVIII@S. aureus complexes into a 96-well plate, diammonium salt of 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) and H2O2 were added to develop color because of the peroxidase mimetics activity of the Co3O4 MNE. A S. aureus concentration within 10-10,000 cfu/mL in milk can be detected (detection limit: 8 cfu/mL). The as-developed method is simple, cost-efficient, and sensitive, which is useful for rapidly diagnosing pathogenic bacteria and helpful to prevent disease outbreaks induced by pathogens in developing countries.