Development of Brain Penetrant Pyridazine Pantothenate Kinase Activators.

Conversion of pantothenate to phosphopantothenate in humans is the first dedicated step in the coenzyme A (CoA) biosynthesis pathway and is mediated by four isoforms of pantothenate kinase. These enzymes are allosterically regulated by acyl-CoA levels, which control the rate of CoA biosynthesis. Small molecule activators of the PANK enzymes that overcome feedback suppression increase CoA levels in cultured cells and animals and have shown great potential for the treatment of pantothenate kinase-associated neurodegeneration and propionic acidemias.

Pantothenate Kinase Activation Restores Brain Coenzyme A in a Mouse Model of Pantothenate Kinase-Associated Neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is characterized by a motor disorder with combinations of dystonia, parkinsonism, and spasticity, leading to premature death. PKAN is caused by mutations in the gene that result in loss or reduction of PANK2 protein function. PANK2 is one of three kinases that initiate and regulate coenzyme A biosynthesis from vitamin B5, and the ability of BBP-671, an allosteric activator of pantothenate kinases, to enter the brain and elevate coenzyme A was investigated.

SB226, an inhibitor of tubulin polymerization, inhibits paclitaxel-resistant melanoma growth and spontaneous metastasis.

Extensive preclinical studies have shown that colchicine-binding site inhibitors (CBSIs) are promising drug candidates for cancer therapy. Although numerous CBSIs were generated and evaluated, but so far the FDA has not approved any of them due to undesired adverse events or insufficient efficacies. We previously reported two very potent CBSIs, the dihydroquinoxalinone compounds 5 m and 5t.

Relief of CoA sequestration and restoration of mitochondrial function in a mouse model of propionic acidemia.

Propionic acidemia (PA, OMIM 606054) is a devastating inborn error of metabolism arising from mutations that reduce the activity of the mitochondrial enzyme propionyl-CoA carboxylase (PCC). The defects in PCC reduce the concentrations of nonesterified coenzyme A (CoASH), thus compromising mitochondrial function and disrupting intermediary metabolism. Here, we use a hypomorphic PA mouse model to test the effectiveness of BBP-671 in correcting the metabolic imbalances in PA.

Targeting KDM4 for treating PAX3-FOXO1-driven alveolar rhabdomyosarcoma.

Chimeric transcription factors drive lineage-specific oncogenesis but are notoriously difficult to target. Alveolar rhabdomyosarcoma (RMS) is an aggressive childhood soft tissue sarcoma transformed by the pathognomonic Paired Box 3-Forkhead Box O1 (PAX3-FOXO1) fusion protein, which governs a core regulatory circuitry transcription factor network. Here, we show that the histone lysine demethylase 4B (KDM4B) is a therapeutic vulnerability for PAX3-FOXO1 RMS.

Phenyl-Glutarimides: Alternative Cereblon Binders for the Design of PROTACs.

Targeting cereblon (CRBN) is currently one of the most frequently reported proteolysis-targeting chimera (PROTAC) approaches, owing to favorable drug-like properties of CRBN ligands, immunomodulatory imide drugs (IMiDs). However, IMiDs are known to be inherently unstable, readily undergoing hydrolysis in body fluids. Here we show that IMiDs and IMiD-based PROTACs rapidly hydrolyze in commonly utilized cell media, which significantly affects their cell efficacy.

X-ray Crystallography-Guided Design, Antitumor Efficacy, and QSAR Analysis of Metabolically Stable Cyclopenta-Pyrimidinyl Dihydroquinoxalinone as a Potent Tubulin Polymerization Inhibitor.

Small molecules that interact with the colchicine binding site in tubulin have demonstrated therapeutic efficacy in treating cancers. We report the design, syntheses, and antitumor efficacies of new analogues of pyridopyrimidine and hydroquinoxalinone compounds with improved drug-like characteristics. Eight analogues, , , , , , , , and , showed significant improvement in metabolic stability and demonstrated strong antiproliferative potency in a panel of human cancer cell lines, including melanoma, lung cancer, and breast cancer.

Design, Synthesis, and Biological Evaluation of Stable Colchicine-Binding Site Tubulin Inhibitors 6-Aryl-2-benzoyl-pyridines as Potential Anticancer Agents.

We previously reported a potent tubulin inhibitor CH-2-77. In this study, we optimized the structure of CH-2-77 by blocking metabolically labile sites and synthesized a series of CH-2-77 analogues. Two compounds, and , preserved the potency while improving the metabolic stability over CH-2-77 by 3- to 4-fold (46.

17-DMAG dually inhibits Hsp90 and histone lysine demethylases in alveolar rhabdomyosarcoma.

Histone lysine demethylases (KDMs) play critical roles in oncogenesis and therefore may be effective targets for anticancer therapy. Using a time-resolved fluorescence resonance energy transfer demethylation screen assay, in combination with multiple orthogonal validation approaches, we identified geldanamycin and its analog 17-DMAG as KDM inhibitors. In addition, we found that these Hsp90 inhibitors increase degradation of the alveolar rhabdomyosarcoma (aRMS) driver oncoprotein PAX3-FOXO1 and induce the repressive epigenetic mark H3K9me3 and H3K36me3 at genomic loci of PAX3-FOXO1 targets.

Bromodomain-Selective BET Inhibitors Are Potent Antitumor Agents against MYC-Driven Pediatric Cancer.

Inhibition of members of the bromodomain and extraterminal (BET) family of proteins has proven a valid strategy for cancer chemotherapy. All BET identified to date contain two bromodomains (BD; BD1 and BD2) that are necessary for recognition of acetylated lysine residues in the N-terminal regions of histones. Chemical matter that targets BET (BETi) also interact via these domains.

[Effects of a Positive Psychology-based Mental Health Promotion Program for High School Students].

Purpose: The purpose of this study was to investigate the effects of a positive psychology-based mental health promotion program for high school students.

Methods: This study used a randomized control group pretest-posttest design. A total of 47 high school students participated from two high schools in Gyeonggi Province.

Dynamic anticipation by Cdk2/Cyclin A-bound p27 mediates signal integration in cell cycle regulation.

p27 is an intrinsically disordered protein (IDP) that inhibits cyclin-dependent kinase (Cdk)/cyclin complexes (e.g., Cdk2/cyclin A), causing cell cycle arrest.

Allosteric Regulation of Mammalian Pantothenate Kinase.

Pantothenate kinase is the master regulator of CoA biosynthesis and is feedback-inhibited by acetyl-CoA. Comparison of the human PANK3·acetyl-CoA complex to the structures of PANK3 in four catalytically relevant complexes, 5'-adenylyl-β,γ-imidodiphosphate (AMPPNP)·Mg, AMPPNP·Mg·pantothenate, ADP·Mg·phosphopantothenate, and AMP phosphoramidate (AMPPN)·Mg, revealed a large conformational change in the dimeric enzyme. The amino-terminal nucleotide binding domain rotates to close the active site, and this allows the P-loop to engage ATP and facilitates required substrate/product interactions at the active site.

Pterin-sulfa conjugates as dihydropteroate synthase inhibitors and antibacterial agents.

The sulfonamide class of antibiotics has been in continuous use for over 70years. They are thought to act by directly inhibiting dihydropteroate synthase (DHPS), and also acting as prodrugs that sequester pterin pools by forming dead end pterin-sulfonamide conjugates. In this study, eight pterin-sulfonamide conjugates were synthesized using a novel synthetic strategy and their biochemical and microbiological properties were investigated.

Identification and characterization of an allosteric inhibitory site on dihydropteroate synthase.

The declining effectiveness of current antibiotics due to the emergence of resistant bacterial strains dictates a pressing need for novel classes of antimicrobial therapies, preferably against molecular sites other than those in which resistance mutations have developed. Dihydropteroate synthase (DHPS) catalyzes a crucial step in the bacterial pathway of folic acid synthesis, a pathway that is absent in higher vertebrates. As the target of the sulfonamide class of drugs that were highly effective until resistance mutations arose, DHPS is known to be a valuable bacterial Achilles heel that is being further exploited for antibiotic development.

Structural polymorphism in the N-terminal oligomerization domain of NPM1.

Nucleophosmin (NPM1) is a multifunctional phospho-protein with critical roles in ribosome biogenesis, tumor suppression, and nucleolar stress response. Here we show that the N-terminal oligomerization domain of NPM1 (Npm-N) exhibits structural polymorphism by populating conformational states ranging from a highly ordered, folded pentamer to a highly disordered monomer. The monomer-pentamer equilibrium is modulated by posttranslational modification and protein binding.

The identification, analysis and structure-based development of novel inhibitors of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase.

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is an essential enzyme in the microbial folate biosynthetic pathway. This pathway has proven to be an excellent target for antimicrobial development, but widespread resistance to common therapeutics including the sulfa drugs has stimulated interest in HPPK as an alternative target in the pathway. A screen of a pterin-biased compound set identified several HPPK inhibitors that contain an aryl substituted 8-thioguanine scaffold, and structural analyses showed that these compounds engage the HPPK pterin-binding pocket and an induced cryptic pocket.

PUMA binding induces partial unfolding within BCL-xL to disrupt p53 binding and promote apoptosis.

Following DNA damage, nuclear p53 induces the expression of PUMA, a BH3-only protein that binds and inhibits the antiapoptotic BCL-2 repertoire, including BCL-xL. PUMA, unique among BH3-only proteins, disrupts the interaction between cytosolic p53 and BCL-xL, allowing p53 to promote apoptosis via direct activation of the BCL-2 effector molecules BAX and BAK. Structural investigations using NMR spectroscopy and X-ray crystallography revealed that PUMA binding induced partial unfolding of two α-helices within BCL-xL.

Structural and biochemical basis for development of influenza virus inhibitors targeting the PA endonuclease.

Emerging influenza viruses are a serious threat to human health because of their pandemic potential. A promising target for the development of novel anti-influenza therapeutics is the PA protein, whose endonuclease activity is essential for viral replication. Translation of viral mRNAs by the host ribosome requires mRNA capping for recognition and binding, and the necessary mRNA caps are cleaved or "snatched" from host pre-mRNAs by the PA endonuclease.

The T4 phage SF1B helicase Dda is structurally optimized to perform DNA strand separation.

Helicases move on DNA via an ATP binding and hydrolysis mechanism coordinated by well-characterized helicase motifs. However, the translocation along single-stranded DNA (ssDNA) and the strand separation of double-stranded (dsDNA) may be loosely or tightly coupled. Dda is a phage T4 SF1B helicase with sequence homology to the Pif1 family of helicases that tightly couples translocation to strand separation.