ABSTRACT
Type II kinase inhibitors bind in the "DFG-out" kinase conformation and are generally considered to be more potent and selective than type I inhibitors, which target a DFG-in conformation. Nine type II inhibitors are currently clinically approved, with more undergoing clinical development. Resistance-conferring secondary mutations emerged with the first series of type II inhibitors, most commonly at residues within the kinase activation loop and at the "gatekeeper" position. Recently, new inhibitors have been developed to overcome such mutations; however, mutations activating other pathways (and/or other targets) have subsequently emerged on occasion. Here, we systematically summarize the secondary mutations that confer resistance to type II inhibitors, the structural basis for resistance, newer inhibitors designed to overcome resistance, as well as the challenges and opportunities for the development of new inhibitors to overcome secondary kinase domain mutations.
Subject(s)
Mutation , Protein Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/chemistry , Humans , AnimalsABSTRACT
Tripterygium wilfordii has been historically employed as a conventional botanical insecticide and a plant of medicinal significance. A new dihydroagarofuran sesquiterpene (1) and a new acyclic compound (2), along with seven known compounds (3-9), have been isolated from the aerial parts of Tripterygium wilfordii. The identification of the structures of novel compounds were accomplished through comprehensive spectroscopic analyses, encompassing HRESIMS, NMR, UV, IR, and a comparative analysis with spectroscopic data from compounds previously characterised. In in-vitro bioassay, compound 8 exhibited significant inhibitory activity for NO release in LPS-induced RAW 264.7 cells, with an IC50 value of 15.7 µM.
ABSTRACT
Recent development of new immune checkpoint inhibitors has been particularly successfully in cancer treatment, but still the majority patients fail to benefit. Converting resistant tumors to immunotherapy sensitive will provide a significant improvement in patient outcome. Here we identify Mi-2ß as a key melanoma-intrinsic effector regulating the adaptive anti-tumor immune response. Studies in genetically engineered mouse melanoma models indicate that loss of Mi-2ß rescues the immune response to immunotherapy in vivo. Mechanistically, ATAC-seq analysis shows that Mi-2ß controls the accessibility of IFN-γ-stimulated genes (ISGs). Mi-2ß binds to EZH2 and promotes K510 methylation of EZH2, subsequently activating the trimethylation of H3K27 to inhibit the transcription of ISGs. Finally, we develop an Mi-2ß-targeted inhibitor, Z36-MP5, which reduces Mi-2ß ATPase activity and reactivates ISG transcription. Consequently, Z36-MP5 induces a response to immune checkpoint inhibitors in otherwise resistant melanoma models. Our work provides a potential therapeutic strategy to convert immunotherapy resistant melanomas to sensitive ones.
Subject(s)
DNA Helicases , Enhancer of Zeste Homolog 2 Protein , Immune Evasion , Melanoma , Animals , Humans , Mice , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/metabolism , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , Immune Evasion/genetics , Melanoma/drug therapy , Methylation , DNA Helicases/genetics , DNA Helicases/metabolismABSTRACT
The animal species is one of the key factors affecting the quality of Bufonis Venenum. The quality of Bufonis Venenum derived from Bufo bufo gargarizans is significantly higher than that from B. melanostictus. Since Bufonis Venenum is from secretions, the conventional identification methods are difficult to identify the animal species due to the lack of the appearance and morphology of the animals. The rapid development of molecular identification technology has provided new methods for the identification of Bufonis Venenum. However, because of the low content and serve degradation of residual DNA in secretions, the research on the molecular identification of Chinese medicinal materials from secretions remains to be carried out. To understand the animal species of Bufonis Venenum, this study collected 83 samples of Bufonis Venenum, including 7 commercially available samples, 5 reference medicinal materials, and 71 animal samples from which Bufonis Venenum was prepared according to the method in the 2020 edition of the Chinese Pharmacopoeia. Different DNA extraction methods were used and compared, and the mitochondrial 16S rRNA gene fragments were amplified, on the basis of which the phylogenetic trees were built. Finally, molecular identification of the animal species of the samples was performed. The results showed that the DNA extracted from Bufonis Venenum by the reagent kit had good quality, and 16S rRNA sequences were successfully amplified from 80 out of the 83 samples. In addition, 71 16S rRNA sequences of the animal species of Bufonis Venenum were downloaded from GenBank. The phylogenetic trees constructed based on the neighbor-joining(NJ) method and the Bayesian inference(BI) method showed that the samples derived from B. bufo gargarizans and B. melanostictus were clustered into separate monophyletic clades, with the support of 100%(NJ) and 1.00(BI), respectively. The animal species of both commercially available samples and reference medicinal materials were B. bufo gargarizans. In conclusion, DNA can be extracted from Bufonis Venenum derived from secretions, and the 16S rRNA gene sequences can be amplified, which can be used for molecular identification of the animal species of Bufonis Venenum. The findings provide a reference for the quality control of Bufonis Venenum and the identification of animal species of medicinal materials derived from secretions.
Subject(s)
Bufanolides , Animals , RNA, Ribosomal, 16S/genetics , Bayes Theorem , Phylogeny , Bufonidae/genetics , DNAABSTRACT
Lithium niobate (LN) crystal plays important roles in future integrated photonics, but it is still a great challenge to efficiently fabricate three-dimensional micro-/nanostructures on it. Here, a femtosecond laser direct writing-assisted liquid back-etching technology (FsLDW-LBE) is proposed to achieve the three-dimensional (3D) microfabrication of lithium niobate (LN) with high surface quality (Ra = 0.422â nm). Various 3D structures, such as snowflakes, graphic arrays, criss-cross arrays, and helix arrays, have been successfully fabricated on the surface of LN crystals. As an example, a microcone array was fabricated on LN crystals, which showed a strong second harmonic signal enhancement with up to 12 times bigger than the flat lithium niobate. The results indicate that the method provides a new approach for the microfabrication of lithium niobate crystals for nonlinear optics.
ABSTRACT
Rhenium sulfide (ReS2) has emerged as a promising two-dimensional material, demonstrating broad-spectrum visible absorption properties that make it highly relevant for diverse optoelectronic applications. Manipulating and optimizing the pathway of photogenerated carriers play a pivotal role in enhancing the efficiency of charge separation and transfer in novel semiconductor composites. This study focuses on the strategic construction of a semiconductor heterostructure by synthesizing ZnO on vacancy-containing ReS2 (VRe-ReS2) through chemical bonding processes. The ingeniously engineered built-in electric field within the heterostructure effectively suppresses the recombination of photogenerated electron-hole pairs. A direct and well-established interfacial connection between VRe-ReS2 and ZnO is achieved through a robust Zn-S bond. This distinctive bond configuration leads to enhanced nonlinear optical conversion efficiency, attributed to shortened carrier migration distances and accelerated charge transfer rates. Furthermore, theoretical calculations unveil the superior chemical interactions between Re vacancies and sulfide moieties, facilitating the formation of Zn-S bonds. The photoluminescence (PL) intensity is increased by the formation of VRe-ReS2 and ZnO heterostructure and the PL quantum yield of VRe-ReS2 is improved. The intricate impact of the Zn-S bond on the nonlinear absorption behavior of the VRe-ReS2@ZnO heterostructure is systematically investigated using femtosecond Z-scan techniques. The charge transfer from ZnO to ReS2 defect levels induces a transition from saturable absorption to reverse saturable absorption in the VRe-ReS2@ZnO heterostructure. Transient absorption measurements further confirm the presence of the Zn-S bond between the interfaces, as evidenced by the prolonged relaxation time (τ3) in the VRe-ReS2@ZnO heterostructure. This study offers valuable insights into the rational construction of heterojunctions through tailored interfacial bonding and surface/interface charge transfer pathways. These endeavors facilitate the modulation of electron transfer dynamics, ultimately yielding superior nonlinear optical conversion efficiency and effective charge regulation in optoelectronic functional materials.
ABSTRACT
Systematic interface and defect engineering strategies have been demonstrated to be an effective way to modulate the electron transfer and nonlinear absorption properties in semiconductor heterojunctions. However, the role played by defects and interfacial strain in electron transfer at the interface of the MoX2 (X = Se, S, Te)@ZnO heterojunction remains poorly understood. Herein, using the MoX2@ZnO heterojunction, we reveal that vacancies play a critical role in the interfacial electron transfer of heterojunctions. Specifically, we present the defect and interface engineering of the MoX2@ZnO heterojunction for controlled charge transfer and electron excitation-relaxation. The experimental characterization combined with first-principles calculations showed that the presence of defects promoted the transport of photogenerated carriers at the heterojunction interface, thereby inhibiting their rapid recombination. The DFT calculation confirmed that the electron band structure, density of states and charge density distribution in the system changed after the formation of Mo-O bonds. On the basis of defects and interfacial stress and the effective charge transfer, the MoX2@ZnO heterojunction exhibited excellent excitation and emission behaviors. The nonlinear optical regulation behavior of TMDs is expected to be realized with the help of the defects and interface/surface synergistically modulated effect of ZnO nanoparticles. The local strain generation on the MoX2@ZnO heterojunction boundary provides a new method for the design of new heterogeneous materials and will be of great significance to investigate the contact physical behavior and application of metals and two-dimensional (2D) semiconductors. This work provides some inspiration for the construction of heterojunctions with rich defects and surface/interface charge transfer channels to promote tunable electron transfer dynamics, thereby achieving a good nonlinear optical conversion efficiency and efficient charge separation in optoelectronic functional materials.
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This study investigated the effect of Xiaoxuming Decoction(XXMD) on the activation of astrocytes after cerebral ischemia/reperfusion(I/R) injury. The model of cerebral IR injury was established using the middle cerebral artery occlusion method. Fluorocitrate(FC), an inhibitor of astrocyte activation, was applied to inhibit astrocyte activation. Rats were randomly divided into a sham group, a model group, a XXMD group, a XXMD+FC group, and a XXMD+Vehicle group. Neurobehavioral changes at 24 hours after cerebral IR injury, cerebral infarction, histopathological changes observed through HE staining, submicroscopic structure of astrocytes observed through transmission electron microscopy, fluorescence intensity of glial fibrillary acidic protein(GFAP) and thrombospondin 1(TSP1) measured through immunofluorescence, and expression of GFAP and TSP1 in brain tissue measured through Western blot were evaluated in rats from each group. The experimental results showed that neurobehavioral scores and cerebral infarct area significantly increased in the model group. The XXMD group, the XXMD+FC group, and the XXMD+Vehicle group all alleviated neurobehavioral changes in rats. The pathological changes in the brain were evident in the model group, while the XXMD group, the XXMD+FC group, and the XXMD+Vehicle group exhibited milder cerebral IR injury in rats. The submicroscopic structure of astrocytes in the model group showed significant swelling, whereas the XXMD group, the XXMD+FC group, and XXMD+Vehicle group protected the submicroscopic structure of astrocytes. The fluorescence intensity and protein expression of GFAP and TSP1 increased in the model group compared with those in the sham group. However, the XXMD group, the XXMD+FC group, and XXMD+Vehicle group all down-regulated the expression of GFAP and TSP1. The combination of XXMD and FC showed a more pronounced effect. These results indicate that XXMD can improve cerebral IR injury, possibly by inhibiting astrocyte activation and down-regulating the expression of GFAP and TSP1.
Subject(s)
Brain Ischemia , Reperfusion Injury , Rats , Animals , Astrocytes , Brain Ischemia/drug therapy , Brain Ischemia/metabolism , Brain , Reperfusion Injury/drug therapy , Reperfusion Injury/metabolism , Infarction, Middle Cerebral ArteryABSTRACT
Chorioretinal disease has become a significant problem affecting human vision. Abnormal expression of vascular endothelial growth factor(VEGF)leads to increased fundus permeability and neovascularization. Vitreous injection of anti-VEGF agents can rapidly inhibit the level of VEGF in the eye and effectively control the development of the disease. At present, anti-VEGF agents are widely administered in ophthalmology. However, studies have shown that intravitreal anti-VEGF agents can reduce plasma VEGF concentration after entering the circulatory system, and the pointless off-target effects of drugs may lead to systemic adverse reactions. For elderly patients, patients with serious comorbidities, lactating women, premature infants and other special populations, attention should be paid to systemic VEGF inhibition after multiple injections. In this paper, in order to provide reference for clinical anti-VEGF therapy, the pharmacokinetics therapy, systemic adverse reactions, contralateral eye effects, and effects of anti-VEGF on breast milk and preterm infants were discussed, and the systemic effects of vitreous injection of anti-VEGF agents were reviewed.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the correlation between the recurrence of cerebral infarction and aspirin resistance (AR)/Chinese medical (CM) constitutions.</p><p><b>METHODS</b>Totally 413 cerebral infarction patients took Aspirin Enteric-coated Tablet (100 mg per day) while receiving routine therapy, 5 days at least in a week. They were followed-up for 12 months. Aspirin sensitivity (AS) was determined using turbidimetry. CM constitutions among patients with different AS were compared. Ratios of AR patients and AS patients of different CM constitutions in cerebral infarction recurrent patients were compared. Platelet membrane glycoproteins (GP) II b HPA-3 gene polymorphism was detected by polymerase chain reaction (PCR) method. Correlation between recurrence of cerebral infarction and AR, bb genotypes, CM constitutions times AS were analyzed by Logistic regression.</p><p><b>RESULTS</b>Totally 11 patients dropped out, 101 (25.12%)with recurrent cerebral infarction and 301 (74.88%) without recurrent cerebral infarction. There were 152 (37.81%) AR patients and 250 (62.19%) AS patients. AR accounted for 26.6% (80/ 301) and AS accounted for 73.4% (221/301) in non-recurrent cerebral infarction patients. AR accounted for 71.3% (72/101) and AS accounted for 28.7% (29/101) in recurrent cerebral infarction patients. There was statistical difference in AR and AS ratios (χ2 = 64.287, P = 0.000). The proportion of yin deficiency constitution (YDC) was the largest [28.3% (43/152)] in AR patients. The proportion of blood stasis constitution (BSC) was the largest [23.6% (59/250)] in AS patients. There was statistical difference in CM constitutions between AR patients and AS patients (χ2 = 21.574, P < 0.01). The former 4 recurrent rates occurred in AR patients of YDC, BSC, damp-phlegm constitution (DPC), qi deficiency constitution (QDC). YDC occupied the first place [22.4% (34/152)]. The former 4 recurrent rates occurred in AS patients of BSC, QDC, DPC, damp-heat constitution (DHC). BSC occupied the first place [3.2% (2/250)]. Compared with non-recurrent cerebral infarction patients and AS patients, bb gene occurred most often, but aa gene and ab gene occurred obviously lesser in non-recurrent cerebral infarction patients and AR patients (χ2 = 20.171, χ2 = 55.139, P < 0.01). AR and bb gene were positively correlated with recurrent cerebral infarction (OR = 18.423, P = 0.000; OR = 1.304, P = 0.028). Body constitutions interacted with AS (OR = 0.707, P = 0.000).</p><p><b>CONCLUSIONS</b>Recurrent cerebral infarction was closely related to AR and constitutional types. The recurrence rate was higher in AR patients of YDC. GP I b HPA-3 bb genotype might be a risk factor for AR and recurrent cerebral infarction.</p>