Structural basis for FGF hormone signalling.

α/ßKlotho coreceptors simultaneously engage fibroblast growth factor (FGF) hormones (FGF19, FGF21 and FGF23)1,2 and their cognate cell-surface FGF receptors (FGFR1-4) thereby stabilizing the endocrine FGF-FGFR complex3-6. However, these hormones still require heparan sulfate (HS) proteoglycan as an additional coreceptor to induce FGFR dimerization/activation and hence elicit their essential metabolic activities6. To reveal the molecular mechanism underpinning the coreceptor role of HS, we solved cryo-electron microscopy structures of three distinct 1:2:1:1 FGF23-FGFR-αKlotho-HS quaternary complexes featuring the 'c' splice isoforms of FGFR1 (FGFR1c), FGFR3 (FGFR3c) or FGFR4 as the receptor component. These structures, supported by cell-based receptor complementation and heterodimerization experiments, reveal that a single HS chain enables FGF23 and its primary FGFR within a 1:1:1 FGF23-FGFR-αKlotho ternary complex to jointly recruit a lone secondary FGFR molecule leading to asymmetric receptor dimerization and activation. However, αKlotho does not directly participate in recruiting the secondary receptor/dimerization. We also show that the asymmetric mode of receptor dimerization is applicable to paracrine FGFs that signal solely in an HS-dependent fashion. Our structural and biochemical data overturn the current symmetric FGFR dimerization paradigm and provide blueprints for rational discovery of modulators of FGF signalling2 as therapeutics for human metabolic diseases and cancer.

Base-Promoted Synthesis of Isoquinolines through a Tandem Reaction of 2-Methyl-arylaldehydes and Nitriles.

A convenient method for preparing 3-aryl isoquinolines via a base-promoted tandem reaction is presented. Simply combining commercially available 2-methyl-arylaldehydes, benzonitriles, NaN(SiMe3)2, and Cs2CO3 enabled the synthesis of a variety of isoquinolines (23 examples, ≤90% yield). Among the syntheses of isoquinolines, the transition metal-free method described here is straightforward, practical, and operationally simple.

Discovery of a doublecortin-like kinase 1 inhibitor to prevent inflammatory responses in acute lung injury.

Doublecortin-like kinase 1 (DCLK1) is a microtubule-associated protein kinase involved in neurogenesis and human cancer. Recent studies have revealed a novel functional role for DCLK1 in inflammatory signaling, thus positioning it as a novel target kinase for respiratory inflammatory disease treatment. In this study, we designed and synthesized a series of NVP-TAE684-based derivatives as novel anti-inflammatory agents targeting DCLK1. Bio-layer interferometry binding screening and kinase assays of the NVP-TAE684 derivatives led to the discovery of an effective DCLK1 inhibitor (a24), with an IC50 of 179.7 nM. Compound a24 effectively inhibited lipopolysaccharide (LPS)-induced inflammation in macrophages with higher potency than the lead compound. Mechanistically, compound a24 inhibited LPS-induced inflammation by inhibiting DCLK1-mediated IKKß phosphorylation. Furthermore, compound a24 showed in vivo anti-inflammatory activity in an LPS-challenged acute lung injury model. These findings suggest that compound a24 may serve as a novel candidate for the development of DCLK1 inhibitors and a potential therapeutic agent for the treatment of inflammatory diseases.

Loss of SATB2 and CDX2 expression is associated with DNA mismatch repair protein deficiency and BRAF mutation in colorectal cancer.

The relationship between the expression of the SATB2 and CDX2 proteins and common molecular changes and clinical prognosis in colorectal cancer (CRC) still needs further clarification. We collected 1180 cases of CRC and explored the association between the expression of SATB2 and CDX2 and clinicopathological characteristics, molecular alterations, and overall survival of CRC using whole-slide immunohistochemistry. Our results showed that negative expression of SATB2 and CDX2 was more common in MMR-protein-deficient CRC than in MMR-protein-proficient CRC (15.8% vs. 6.0%, P = 0.001; 14.5% vs. 4.0%, P = 0.000, respectively). Negative expression of SATB2 and CDX2 was more common in BRAF-mutant CRC than in BRAF wild-type CRC (17.2% vs. 6.1%, P = 0.003; 13.8% vs. 4. 2%; P = 0.004, respectively). There was no relationship between SATB2 and/or CDX2 negative expression and KRAS, NRAS, and PIK3CA mutations. The lack of expression of SATB2 and CDX2 was associated with poor histopathological features of CRC. In multivariate analysis, negative expression of SATB2 (P = 0.030), negative expression of CDX2 (P = 0.043) and late clinical stage (P = 0.000) were associated with decreased overall survival of CRC. In conclusion, the lack of SATB2 and CDX2 expression in CRC was associated with MMR protein deficiency and BRAF mutation, but not with KRAS, NRAS and PIK3CA mutation. SATB2 and CDX2 are prognostic biomarkers in patients with CRC.

[Study on methods measuring mechanical properties of arterial wall by macroscopic indentation].

Accurately evaluating the local biomechanics of arterial wall is crucial for diagnosing and treating arterial diseases. Indentation measurement can be used to evaluate the local mechanical properties of the artery. However, the effects of the indenter's geometric structure and the analysis theory on measurement results remain uncertain. In this paper, four kinds of indenters were used to measure the pulmonary aorta, the proximal thoracic aorta and the distal thoracic aorta in pigs, and the arterial elastic modulus was calculated by Sneddon and Sirghi theory to explore the influence of the indenter geometry and analysis theory on the measured elastic modulus. The results showed that the arterial elastic modulus measured by cylindrical indenter was lower than that measured by spherical indenter. In addition, compared with the calculated results of Sirghi theory, the Sneddon theory, which does not take adhesion forces in account, resulted in slightly larger elastic modulus values. In conclusion, this study provides parametric support for effective measurement of arterial local mechanical properties by millimeter indentation technique.

Corneal biomechanical stiffness and histopathological changes after in vivo repeated accelerated corneal cross-linking in cat eyes.

Corneal cross-linking (CXL) has been proved efficiency for treating progressive keratoconus and other corneal ectasia diseases by stabilizing corneal geometry and biomechanics. However, the necessity of repeated CXL treatment in patients is unknown. This study aimed to investigate corneal biomechanical stiffness and change in corneal histopathological characteristics after repeated accelerated CXL (A-CXL) in cat eyes. A-CXL was performed with 0.1% riboflavin applied for 10 min, followed by ultraviolet A irradiation at 30 mW/cm2 for 3 min at 365 nm in 15 domestic cats. Corneas (n = 30) were divided into three groups: one-time accelerated corneal cross-linking (A-CXL*1 group), repeated accelerated corneal cross-linking (A-CXL*2 group), and an untreated control group. In A-CXL*2 group, A-CXL was repeated at 1-month intervals. In vivo ocular examinations were performed pre- and postoperatively. Biomechanical analysis was performed using a biotester biaxial testing system. We used the Mooney-Rivlin strain-energy function to describe corneal material properties. No infection in any case after A-CXL was observed. Biomechanical tests showed that the stress-strain curves of the two A-CXL groups were significantly different from those of the control group (P < 0.01), whereas stress-strain curve of the A-CXL*2 group was similar to that of the A-CXL*1 group (P > 0.05). Delayed epithelial healing and haze were observed 1 month after surgery. Stromal demarcation line depth measured with anterior spectral-domain optical coherence tomography was 187.6 ± 20.4 and 197.1 ± 11.5 µm for the A-CXL*1 and A-CXL*2 groups, respectively (P > 0.05). These results show that A-CXL can increase corneal biomechanics in cat eyes. The biomechanical enhancement of cat corneas treated with repeated A-CXL at 1-month intervals was similar to that of performing a one-time A-CXL. Repeated cross-linking procedures at short intervals may increase the risk of adverse reactions, and more caution should be taken in clinical applications.

RPBP: Deep Retrosynthesis Reaction Prediction Based on Byproducts.

Retrosynthesis prediction is crucial in organic synthesis and drug discovery, aiding chemists in designing efficient synthetic routes for target molecules. Data-driven deep retrosynthesis prediction has gained importance due to new algorithms and enhanced computing power. Although existing models show certain predictive power on the USPTO-50K benchmark data set, no one considers the effects of byproducts during the prediction process, which may be due to the lack of byproduct information in the benchmark data set. Here, we propose a novel two-stage retrosynthesis reaction prediction framework based on byproducts called RPBP. First, RPBP predicts the byproduct involved in the reaction based on the product molecule. Then, it handles an end-to-end prediction problem based on the prediction of reactants by product and byproduct. Unlike other methods that first identify the potential reaction center and then predict reactant molecules, RPBP considers additional information from byproducts, such as reaction reagents, conditions, and sites. Interestingly, adding byproducts reduces model learning complexity in natural language processing (NLP). Our RPBP model achieves 54.7% and 66.6% top-1 retrosynthesis prediction accuracy when the reaction class is unknown and known, respectively. It outperforms existing methods for known-class reactions, thanks to the rich chemical information in byproducts. The prediction of four kinase drugs from the literature demonstrates the model's practicality and potential to accelerate drug discovery.

Identification of exosomal hsa-miR-483-5p as a potential biomarker for hepatocellular carcinoma via microRNA expression profiling of tumor-derived exosomes.

To date, most studies of exosomes related to hepatocellular carcinoma (HCC) have used commercial cancer cell lines or patient plasma as source material. In this study, we isolated exosomes directly from HCC tissues to investigate the potential of exosomal contents as biomarkers for HCC. Exosomes were identified and verified using transmission electron microscopy, nano-flow cytometry analysis, and western blotting. Tissue-derived exosomal miRNA expression was profiled by high-throughput sequencing, and differential expression of miRNAs was validated by quantitative real-time polymerase chain reaction analysis. The diagnostic performance of differentially expressed exosomal miRNAs for HCC was evaluated by receiver operating characteristic curve analysis. Target genes of these miRNAs were verified using luciferase reporter assays, and their functions were studied through in vitro and rescue assays. In total, 225 differentially expressed exosomal miRNAs were identified in HCC samples compared with adjacent liver tissues, and some were associated with HCC tumorigenesis and progression. Comparison of the expression profiles of tissue-derived and plasma-derived exosomal miRNAs identified hsa-miR-483-5p as the only differentially expressed miRNA detected in both HCC tissue and plasma, and this was in a validation group of HCC patients. Analysis of the diagnostic performance of plasma exosomal hsa-miR-483-5p or plasma hsa-miR-483-5p found that both could differentiate HCC and non-HCC cases. In vitro ectopic miR-483-5p expression promoted HCC cell proliferation. CDK15 was confirmed to bind with miR-483-5p directly, and thus, miR-483-5p may function by downregulating CDK15. Hsa-miR-483-5p represents a potential specific and sensitive biomarker for HCC diagnosis.

Synergistic anti-oxidant and anti-inflammatory effects of ceria/resatorvid co-decorated nanoparticles for acute lung injury therapy.

BACKGROUND: Acute lung injury (ALI) is a critical inflammatory response syndrome that rapidly develops into acute respiratory distress syndrome (ARDS). Currently, no effective therapeutic modalities are available for patients with ALI/ARDS. According to recent studies, inhibiting both the release of pro-inflammatory cytokines and the formation of reactive oxygen species (ROS) as early as possible may be a promising therapy for ALI. RESULTS: In this study, a ROS-responsive nano-delivery system based on oxidation-sensitive chitosan (Ox-CS) was fabricated for the simultaneous delivery of Ce NPs and RT. The in vitro experiments have shown that the Ox-CS/Ceria-Resatorvid nanoparticles (Ox-CS/CeRT NPs) were rapidly and efficiently internalised by inflammatory endothelial cells. Biological evaluations validated the significant attenuation of ROS-induced oxidative stress and cell apoptosis by Ox-CS/CeRT NPs, while maintaining mitochondrial function. Additionally, Ox-CS/CeRT NPs effectively inhibited the release of pro-inflammatory factors. After intraperitoneal (i.p.) administration, Ox-CS/CeRT NPs passively targeted the lungs of LPS-induced inflamed mice and released the drug activated by the high ROS levels in inflammatory tissues. Finally, Ox-CS/CeRT NPs significantly alleviated LPS-induced lung injury through inhibiting both oxidative stress and pro-inflammatory cytokine expression. CONCLUSIONS: The created Ox-CS/CeRT NPs could act as a prospective nano-delivery system for a combination of anti-inflammatory and anti-oxidant therapy of ALI.

CircSTAM inhibits migration and invasion of trophoblast cells by regulating miR-148a-5p/PTEN axis.

BACKGROUND: The mechanisms underlying the pathogenesis of preeclampsia (PE) remains unclear. Exploring the molecular players in PE progression can provide insights into targeted therapy. METHODS: The expression levels of circSTAM in placental chorionic tissues of PE patients and normal pregnant women were compared by RT-qPCR. CircSTAM was knocked down by small interfering RNA to investigate its role in migration, invasion and epithelial-mesenchymal transformation (EMT) of trophoblast HTR-8/SVneo cells. The downstream target of circSTAM was predicted using online bioinformatics resources, and their molecular interaction was examined by luciferase reporter assay. RESULTS: CircSTAM was upregulated in PE placenta tissues in comparison to normal placental tissues. CircSTAM knockdown significantly enhanced cellular invasion, migration, as well as EMT. Mir-148a-5p was identified as a target of circSTAM to regulate cell migration and invasion. Mir-148a-5p negatively regulated PTEN expression in trophoblast HTR-8 /SVneo cells. CONCLUSION: In summary, circSTAM upregulation in PE trophoblasts promoted the invasion, migration and EMT. CircSTAM may modulate trophoblast phenotype by impinging on mir-148a-5p/PTEN axis. These data provided novel insights into the pathogenesis of PE.

Molecular basis for receptor tyrosine kinase A-loop tyrosine transphosphorylation.

A long-standing mystery shrouds the mechanism by which catalytically repressed receptor tyrosine kinase domains accomplish transphosphorylation of activation loop (A-loop) tyrosines. Here we show that this reaction proceeds via an asymmetric complex that is thermodynamically disadvantaged because of an electrostatic repulsion between enzyme and substrate kinases. Under physiological conditions, the energetic gain resulting from ligand-induced dimerization of extracellular domains overcomes this opposing clash, stabilizing the A-loop-transphosphorylating dimer. A unique pathogenic fibroblast growth factor receptor gain-of-function mutation promotes formation of the complex responsible for phosphorylation of A-loop tyrosines by eliminating this repulsive force. We show that asymmetric complex formation induces a more phosphorylatable A-loop conformation in the substrate kinase, which in turn promotes the active state of the enzyme kinase. This explains how quantitative differences in the stability of ligand-induced extracellular dimerization promotes formation of the intracellular A-loop-transphosphorylating asymmetric complex to varying extents, thereby modulating intracellular kinase activity and signaling intensity.

Curcumin Derivative C66 Suppresses Pancreatic Cancer Progression through the Inhibition of JNK-Mediated Inflammation.

Pancreatic adenocarcinoma is by far the deadliest type of cancer. Inflammation is one of the important risk factors in tumor development. However, it is not yet clear whether deterioration in pancreatic cancer patients is related to inflammation, as well as the underlying mechanism. In addition, JNK is abnormally activated in pancreatic cancer cells and the JNK inhibitor C66 reduces the inflammatory microenvironment in the tumor. Therefore, the aim of this study was to evaluate the role of C66 in the proliferation and migration of pancreatic cancer. Our results showed that various inflammatory cytokines, such as IL-1ß, IL-6, IL-8, and IL-15, were more expressed in pancreatic cancer than in the matching normal tissue. Furthermore, C66, a curcumin analogue with good anti-inflammatory activity, inhibited the proliferation and migration of pancreatic cancer cells in a dose-dependent manner, and effectively inhibited the expression of the above inflammatory factors. Our previous research demonstrated that C66 prevents the inflammatory response by targeting JNK. Therefore, in this study, JNK activity in pancreatic cancer cells was investigated, revealing that JNK was highly activated, and the treatment with C66 inhibited the phosphorylation of JNK. Next, shJNK was used to knockdown JNK expression in pancreatic cancer cells to further confirm the role of JNK in the proliferation and migration of this tumor, as well as in the inflammatory tumor microenvironment (TME). The results demonstrated that JNK knockdown could significantly inhibit the proliferation and migration of pancreatic cancer. Moreover, the low JNK expression in pancreatic cancer cells significantly inhibited the expression of various inflammatory factors. These results indicated that C66 inhibited the progression of pancreatic cancer through the inhibition of JNK-mediated inflammation.

Stage-specific regulation of purine metabolism during infectious growth and sexual reproduction in Fusarium graminearum.

Ascospores generated during sexual reproduction are the primary inoculum for the wheat scab fungus Fusarium graminearum. Purine metabolism is known to play important roles in fungal pathogens but its lifecycle stage-specific regulation is unclear. By characterizing the genes involved in purine de novo and salvage biosynthesis pathways, we showed that de novo syntheses of inosine, adenosine and guanosine monophosphates (IMP, AMP and GMP) are important for vegetative growth, sexual/asexual reproduction, and infectious growth, whereas purine salvage synthesis is dispensable for these stages in F. graminearum. Addition of GMP rescued the defects of the Fgimd1 mutant in vegetative growth and conidiation but not sexual reproduction, whereas addition of AMP rescued all of these defects of the Fgade12 mutant, suggesting that the function of de novo synthesis of GMP rather than AMP is distinct in sexual stages. Moreover, Acd1, an ortholog of AMP deaminase, is dispensable for growth but essential for ascosporogenesis and pathogenesis, suggesting that AMP catabolism has stage-specific functions during sexual reproduction and infectious growth. The expression of almost all the genes involved in de novo purine synthesis is downregulated during sexual reproduction and infectious growth relative to vegetative growth. This study revealed that F. graminearum has stage-specific regulation of purine metabolism during infectious growth and sexual reproduction.

[The effect of parasitic ions on riboflavin permeability and cross-linking effectiveness in iontophoresis-assisted scleral cross-linking].

The effect of parasitic ions on the results of ultraviolet A (UVA) cross-linking in iontophoresis was still not clear. In this work, the porcine sclera was cross-linked by riboflavin lactate Ringer's solution (group A) and riboflavin normal saline (group B) in vitro, respectively. The concentration of parasitic ions in the solution was calculated. In addition, the average fluorescence intensity, penetration depth and concentration after the introduction of riboflavin and the mechanical properties of cross-linked sclera tissue were measured. The ranges of diffusion coefficient of the two solutions were also calculated, respectively. The results showed that more kinds of parasitic ions were detected in group A compared with group B, while the average fluorescence intensity, penetration depth and concentration of riboflavin and scleral elastic modulus in group B were significantly higher than those in group A when the penetration time was 10 minutes. Besides, the diffusion coefficient of riboflavin in group B was about 1.5 times larger than that in group A. The results suggested that the species of parasitic ions has a great impact on the permeability of riboflavin, and affects the mechanical properties of cross-linked sclera. The above results could provide a reference for improving the efficiency of riboflavin introduction and optimizing the formula of riboflavin in iontophoresis scleral cross-linking.

An extended transfer matrix method for measuring acoustical properties of porous materials beyond the cut-off frequency.

In the field of measuring the complex wave number and characteristic impedance of porous materials, available impedance tube approaches assume that only plane wave is propagating such that the maximum frequency is limited below the cut-off frequency of the first higher order mode. This indicates that if measurements at higher frequencies are required, the tube size has to be reduced, as well as the size of porous material sample, which may cause inaccurate results due to tube attenuation and edge-constraint effects. Through simulations, this paper presents an extended transfer matrix method to remove the plane wave assumption based on the fact that the propagation of plane wave through the porous sample can be characterized by the same transfer matrix whether higher order modes exist or not. This method arranges measuring points upstream and downstream the sample for implementing mode decomposition to extract the transfer matrix for plane wave in a multi-modal field. From the matrix elements, the complex wave number and characteristic impedance are determined in the same way as the original transfer matrix method. Based on numerical simulations and the Monte Carlo approach, the method effectiveness and a suitable measuring points layout are studied in this paper.

Genome-wide A-to-I RNA editing in fungi independent of ADAR enzymes.

Yeasts and filamentous fungi do not have adenosine deaminase acting on RNA (ADAR) orthologs and are believed to lack A-to-I RNA editing, which is the most prevalent editing of mRNA in animals. However, during this study with the PUK1(FGRRES_01058) pseudokinase gene important for sexual reproduction in Fusarium graminearum, we found that two tandem stop codons, UA(1831)GUA(1834)G, in its kinase domain were changed to UG(1831)GUG(1834)G by RNA editing in perithecia. To confirm A-to-I editing of PUK1 transcripts, strand-specific RNA-seq data were generated with RNA isolated from conidia, hyphae, and perithecia. PUK1 was almost specifically expressed in perithecia, and 90% of transcripts were edited to UG(1831)GUG(1834)G. Genome-wide analysis identified 26,056 perithecium-specific A-to-I editing sites. Unlike those in animals, 70.5% of A-to-I editing sites inF. graminearum occur in coding regions, and more than two-thirds of them result in amino acid changes, including editing of 69PUK1-like pseudogenes with stop codons in ORFs.PUK1orthologs and other pseudogenes also displayed stage-specific expression and editing in Neurospora crassa and F. verticillioides Furthermore,F. graminearum differs from animals in the sequence preference and structure selectivity of A-to-I editing sites. Whereas A's embedded in RNA stems are targeted by ADARs, RNA editing inF. graminearum preferentially targets A's in hairpin loops, which is similar to the anticodon loop of tRNA targeted by adenosine deaminases acting on tRNA (ADATs). Overall, our results showed that A-to-I RNA editing occurs specifically during sexual reproduction and mainly in the coding regions in filamentous ascomycetes, involving adenosine deamination mechanisms distinct from metazoan ADARs.

[Experimental study on mechanical properties of the ventral and the dorsal tissues of porcine descending aorta].

The mechanical properties of the aorta tissue is not only important for maintaining the cardiovascular health, but also is closely related to the development of cardiovascular diseases. There are obvious differences between the ventral and dorsal tissues of the descending aorta. However, the cause of the difference is still unclear. In this study, a biaxial tensile approach was used to determine the parameters of porcine descending aorta by analyzing the stress-strain curves. The strain energy functions Gasser-Ogden-Holzapfel was adopted to characterize the orthotropic parameters of mechanical properties. Elastic Van Gieson (EVG) and Sirius red stain were used to observe the microarchitecture of elastic and collagen fibers, respectively. Our results showed that the tissue of descending aorta had more orthotropic and higher elastic modulus in the dorsal region compared to the ventral region in the circumferential direction. No significant difference was found in hyperelastic constitutive parameters between the dorsal and ventral regions, but the angle of collagen fiber was smaller than 0.785 rad (45°) in both dorsal and ventral regions. The arrangement of fiber was inclined to be circumferential. EVG and Sirius red stain showed that in outer-middle membrane of the descending aorta, the density of elastic fibrous layer of the ventral region was higher than that of the dorsal region; the amount of collagen fibers in dorsal region was more than that of the ventral region. The results suggested that the difference of mechanical properties between the dorsal and ventral tissues in the descending aorta was related to the microstructure of the outer membrane of the aorta. In the relatively small strain range, the difference in mechanical properties between the ventral and dorsal tissues of the descending aorta can be ignored; when the strain is higher, it needs to be treated differently. The results of this study provide data for the etiology of arterial disease (such as arterial dissection) and the design of artificial blood vessel.

Experimental ray-tracing with point diffraction interferometry and its application in focal length measurement.

A novel method that could experimentally trace the ray propagation of an optical system based on point diffraction interferometry (PDI) is presented. The ray represented by the line connecting two point light sources (PLS) intersects with two parallel photographic planes, which are separated at a distance. The intersections of the ray defined by the PLSs with the planes occur where the optical path difference is a maximum and can be determined from interferograms on the photographic planes. The ray is determined by connecting the two intersections. Using fibers as the PLSs and CCD arrays as the photographic planes, we demonstrate its principle and its application in focal length measurement through experiments.

Theoretical studies on FGFR isoform selectivity of FGFR1/FGFR4 inhibitors by molecular dynamics simulations and free energy calculations.

The activation and overexpression of fibroblast growth factor receptors (FGFRs) are highly correlated with a variety of cancers. Most small molecule inhibitors of FGFRs selectively target FGFR1-3, but not FGFR4. Hence, designing highly selective inhibitors towards FGFR4 remains a great challenge because FGFR4 and FGFR1 have a high sequence identity. Recently, two small molecule inhibitors of FGFRs, ponatinib and AZD4547, have attracted huge attention. Ponatinib, a type II inhibitor, has high affinity towards FGFR1/4 isoforms, but AZD4547, a type I inhibitor of FGFR1, displays much reduced inhibition toward FGFR4. In this study, conventional molecular dynamics (MD) simulations, molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculations and umbrella sampling (US) simulations were carried out to reveal the principle of the binding preference of ponatinib and AZD4547 towards FGFR4/FGFR1. The results provided by MM/GBSA illustrate that ponatinib has similar binding affinities to FGFR4 and FGFR1, while AZD4547 has much stronger binding affinity to FGFR1 than to FGFR4. A comparison of the individual energy terms suggests that the selectivity of AZD4547 towards FGFR1 versus FGFR4 is primarily controlled by the variation of the van der Waals interactions. The US simulations reveal that the PMF profile of FGFR1/AZD4547 has more peaks and valleys compared with that of FGFR4/AZD4547, suggesting that the dissociation process of AZD4547 from FGFR1 are easily trapped into local minima. Moreover, it is observed that FGFR1/AZD4547 has much higher PMF depth than FGFR4/AZD4547, implying that it is more difficult for AZD4547 to escape from FGFR1 than from FGFR4. The physical principles provided by this study extend our understanding of the binding mechanisms and provide valuable guidance for the rational design of FGFR isoform selective inhibitors.

Curcumin analogue, A13, exhibits anti-leukemia effect via inhibiting STAT3.

Abnormal activation of signal transducer and activator of transcription 3 (STAT3) was reported in some leukemia, and inhibition of STAT3 can be the strategy for the leukemia treatment in clinic. In this study, we tested the anti-tumor effect of compound A13, a water-soluble analogue of curcumin, in vitro and in vivo. Herein, we show that A13 was able to reduce the viability of mastocytoma (P815 cells) and reticulum cell sarcoma (A20 cells) as measured by MTS assay. This effect was accompanied by a marked increase in the proportion of apoptotic cells as measured by flow cytometry. Furthermore, Western blot analysis suggested that the anti-leukemia effect of A13 was realized via STAT3 inhibition. In addition, systemic treatment with A13 in the A20-bearing mice for 60 days resulted in a significant improvement of survival rate and marked reduction of liver metastasis. In summary, our data show that the A13 treatment could effectively be applied to acute leukemia via inhibiting STAT3 signaling pathway.