Affinity-Driven Covalent Modulator of the Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) Cascade.

Traditional medicines provide a fertile ground to explore potent lead compounds, yet their transformation into modern drugs is fraught with challenges in deciphering the target that is mechanistically valid for its biological activity. Herein we reveal that (Z)-(+)-isochaihulactone (1) exhibited significant inhibition against multiple-drug-resistant (MDR) cancer cell lines and mice xenografts. NMR spectroscopy showed that 1 resisted an off-target thiolate, thus indicating that 1 was a target covalent inhibitor (TCI). By identifying the pharmacophore of 1 (α,ß-unsaturated moiety), a probe derived from 1 was designed and synthesized for TCI-oriented activity-based proteome profiling. By MS/MS and computer-guided molecular biology approaches, an affinity-driven Michael addition of the noncatalytic C247 residue of GAPDH was found to control the "ON/OFF" switch of apoptosis through non-canonically nuclear GAPDH translocation, which bypasses the common apoptosis-resistant route of MDR cancers.

Avenaciolides: potential MurA-targeted inhibitors against peptidoglycan biosynthesis in methicillin-resistant Staphylococcus aureus (MRSA).

Discovery of new antibiotics for combating methicillin-resistant Staphylococcus aureus (MRSA) is of vital importance in the post-antibiotic era. Here, we report four avenaciolide derivatives (1-4) isolated from Neosartorya fischeri, three of which had significant antimicrobial activity against MRSA. The morphology of avenaciolide-treated cells was protoplast-like, which indicated that cell wall biosynthesis was interrupted. Comparing the structures and minimum inhibitory concentrations of 1-4, the α,ß-unsaturated carbonyl group seems to be an indispensable moiety for antimicrobial activity. Based on a structural similarity survey of other inhibitors with the same moiety, we revealed that MurA was the drug target. This conclusion was validated by (31)P NMR spectroscopy and MS/MS analysis. Although fosfomycin, which is the only clinically used MurA-targeted antibiotic, is ineffective for treating bacteria harboring the catalytically important Cys-to-Asp mutation, avenaciolides 1 and 2 inhibited not only wild-type but also fosfomycin-resistant MurA in an unprecedented way. Molecular simulation revealed that 2 competitively perturbs the formation of the tetrahedral intermediate in MurA. Our findings demonstrated that 2 is a potent inhibitor of MRSA and fosfomycin-resistant MurA, laying the foundation for the development of new scaffolds for MurA-targeted antibiotics.

Surgical decompression improves recovery from neurological deficit and may provide a survival benefit in patients with diffuse large B-cell lymphoma-associated spinal cord compression: a case-series study.

BACKGROUND: Malignancy-associated spinal cord compression is generally treated by surgical decompression, radiotherapy or a combination of both. Since diffuse large B-cell lymphoma (DLBCL) is highly sensitive to both chemotherapy and radiotherapy, the role of surgical decompression in the treatment of DLBCL-associated spinal cord compression remains unclear. We therefore conducted a retrospective review to investigate the impact of surgical decompression on recovery from neurological deficit caused by DLBCL-associated spinal cord compression and patients' overall survival. METHODS: Between March 2001 and September 2011, 497 newly diagnosed DLBCL patients were reviewed, and 11 cases had DLBCL-associated spinal cord compression. Six cases were treated surgically and five cases nonsurgically. RESULTS: The rates of complete recovery from neurological deficit were 100% (6/6) and 20% (1/5) for patients in the surgical and nonsurgical groups, respectively (P = 0.015), while the median survival for patients in the surgical and nonsurgical groups was 48.6 months and 17.8 months, respectively (P = 0.177). CONCLUSIONS: We conclude that surgical decompression can improve recovery from neurological deficit in patients with DLBCL-associated spinal cord compression, possibly providing these patients a survival benefit.

Unlocking Synergistic Potential: Enhancing Regorafenib Efficacy in Hepatocellular Carcinoma Through Combination Therapy With 18ß-Glycyrrhetinic Acid.

BACKGROUND/AIM: Hepatocellular carcinoma (HCC) is a primary liver cancer with limited treatment options and poor prognosis. Regorafenib, a multi-kinase inhibitor, has shown promise in HCC treatment; however, its efficacy can be enhanced by combining it with other agents. 18ß-glycyrrhetinic acid (18ß-gly) is a natural compound with potential anti-cancer properties. MATERIALS AND METHODS: The toxicity and mechanism of regorafenib and 18ß-gly was assessed on Hep3B cells, Huh7 cells, and Hep3B bearing animal model. RESULTS: The combination of regorafenib and 18ß-gly exhibited synergistic toxicity in HCC cells and animal model. Importantly, no significant differences in body weight or major tissue damage were observed after treatment with the combination of two drugs. Furthermore, the combination treatment modulated apoptosis-related markers and the mTOR signaling pathway. CONCLUSION: The study provides evidence for the synergistic effect of 18ß-gly and regorafenib in a HCC model. The combination treatment modulated apoptosis-related markers and the mTOR signaling pathway, highlighting potential mechanisms underlying its therapeutic efficacy.

Metformin-induced caveolin-1 expression promotes T-DM1 drug efficacy in breast cancer cells.

Trastuzumab emtansine (T-DM1) is an antibody drug conjugate (ADC) that was recently approved for the treatment of HER-2-positive metastatic breast cancer. The drug sensitivity of ADCs depends mainly on the internalization efficiency of the drug. Caveolin-1 was shown to promote T-DM1 internalization and enhance drug sensitivity. Whether caveolin-1 can be overexpressed to improve T-DM1 efficacy is interesting and has the potential for clinical application. In this study, diabetes drug metformin was investigated in terms of induction of caveolin-1 expression for increased efficacy of subsequent T-DM1 application. BT-474 cells were pretreated with metformin, followed by combined therapy with metformin and T-DM1. The T-DM1 internalization and drug efficacy were determined, and the protein expressions for signal transduction were also monitored. Caveolin-1 shRNA was applied to suppress endogenous caveolin-1 expression, and the ability of metformin to promote T-DM1 efficacy was investigated. Result showed that in BT-474 cells pretreated with metformin, cellular caveolin-1 overexpression was induced, which then promoted drug efficacy by enhancing T-DM1 internalization. As cellular caveolin-1 was suppressed by shRNA, the effect of metformin-enhanced T-DM1 cytotoxicity was decreased. This study demonstrated that metformin can be applied prior to T-DM1 treatment to improve the clinical efficacy of T-DM1 by enhancing caveolin-1-mediated endocytosis.

Structural basis for fragmenting the exopolysaccharide of Acinetobacter baumannii by bacteriophage ΦAB6 tailspike protein.

With an increase in antibiotic-resistant strains, the nosocomial pathogen Acinetobacter baumannii has become a serious threat to global health. Glycoconjugate vaccines containing fragments of bacterial exopolysaccharide (EPS) are an emerging therapeutic to combat bacterial infection. Herein, we characterize the bacteriophage ΦAB6 tailspike protein (TSP), which specifically hydrolyzed the EPS of A. baumannii strain 54149 (Ab-54149). Ab-54149 EPS exhibited the same chemical structure as two antibiotic-resistant A. baumannii strains. The ΦAB6 TSP-digested products comprised oligosaccharides of two repeat units, typically with stoichiometric pseudaminic acid (Pse). The 1.48-1.89-Å resolution crystal structures of an N-terminally-truncated ΦAB6 TSP and its complexes with the semi-hydrolyzed products revealed a trimeric ß-helix architecture that bears intersubunit carbohydrate-binding grooves, with some features unusual to the TSP family. The structures suggest that Pse in the substrate is an important recognition site for ΦAB6 TSP. A region in the carbohydrate-binding groove is identified as the determinant of product specificity. The structures also elucidated a retaining mechanism, for which the catalytic residues were verified by site-directed mutagenesis. Our findings provide a structural basis for engineering the enzyme to produce desired oligosaccharides, which is useful for the development of glycoconjugate vaccines against A. baumannii infection.

Galactomannan from Antrodia cinnamomea Enhances the Phagocytic Activity of Macrophages.

Galactomannan with an octasaccharide-repeating unit (ACP) was isolated from Taiwan medicinal mushroom Antrodia cinnamomea, and its chemical structure was determined herein. ACP significantly enhanced the phagocytosis and bactericidal activity of J774A.1 murine macrophages against Escherichia coli, with prospects for developing a new immunomodulatory compound or adjuvant in immunotherapy and vaccination.

The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions.

In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO3(2-) and DCCM/SeO3(2-) complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

Nitrophenylboronic acids as highly chemoselective probes to detect hydrogen peroxide in foods and agricultural products.

Hydrogen peroxide is commonly used in the food processing industry as a chlorine-free bleaching and sterilizing agent, but excessive amounts of residual hydrogen peroxide have led to cases of food poisoning. Here we describe the development of a novel nonenzymatic colorimetric method for the determination of residual hydrogen peroxide in foods and agricultural products. Nitrophenylboronic acids chemoselectively react with hydrogen peroxide under alkaline conditions to produce yellow nitrophenolates. Of the three nitrophenylboronic acid isomers tested, the p-isomer displayed the highest sensitivity for hydrogen peroxide and the fastest reaction kinetics. The reaction product, p-nitrophenolate, has an absorption maximum at 405 nm and a good linear correlation between the hydrogen peroxide concentration and the A(405) values was obtained. We successfully applied this convenient and rapid method for hydrogen peroxide determination to samples of dried bean curds and disposable chopsticks, thereby demonstrating its potential in foods and agricultural industries.

Anti-control of chaos of single time-scale brushless DC motor.

Anti-control of chaos of single time-scale brushless DC motors is studied in this paper. In order to analyse a variety of periodic and chaotic phenomena, we employ several numerical techniques such as phase portraits, bifurcation diagrams and Lyapunov exponents. Anti-control of chaos can be achieved by adding an external constant term or an external periodic term.