CPPF, A Novel Microtubule Targeting Anticancer Agent, Inhibits the Growth of a Wide Variety of Cancers.

In the past, several microtubule targeting agents (MTAs) have been developed into successful anticancer drugs. However, the usage of these drugs has been limited by the acquisition of drug resistance in many cancers. Therefore, there is a constant demand for the development of new therapeutic drugs. Here we report the discovery of 5-5 (3-cchlorophenyl)-N-(3-pyridinyl)-2-furamide (CPPF), a novel microtubule targeting anticancer agent. Using both 2D and 3D culture systems, we showed that CPPF was able to suppress the proliferation of diverse cancer cell lines. In addition, CPPF was able to inhibit the growth of multidrug-resistant cell lines that are resistant to other MTAs, such as paclitaxel and colchicine. Our results showed that CPPF inhibited growth by depolymerizing microtubules leading to mitotic arrest and apoptosis. We also confirmed CPPF anticancer effects in vivo using both a mouse xenograft and a two-step skin cancer mouse model. Using established zebrafish models, we showed that CPPF has low toxicity in vivo. Overall, our study proves that CPPF has the potential to become a successful anticancer chemotherapeutic drug.

Inhibitory effects of flavonoids isolated from Sophora flavescens on indoleamine 2,3-dioxygenase 1 activity.

Indoleamine 2,3-dioxygenase 1 (IDO1), a tryptophan catabolising enzyme, is known as a tumour cell survival factor that causes immune escape in several types of cancer. Flavonoids of Sophora flavescens have a variety of biological benefits for humans; however, cancer immunotherapy effect has not been fully investigated. The flavonoids (1-6) isolated from S. flavescens showed IDO1 inhibitory activities (IC50 4.3-31.4 µM). The representative flavonoids (4-6) of S. flavescens were determined to be non-competitive inhibitors of IDO1 by kinetic analyses. Their binding affinity to IDO1 was confirmed using thermal stability and surface plasmon resonance (SPR) assays. The molecular docking analysis and mutagenesis assay revealed the structural details of the interactions between the flavonoids (1-6) and IDO1. These results suggest that the flavonoids (1-6) of S. flavescens, especially kushenol E (6), as IDO1 inhibitors might be useful in the development of immunotherapeutic agents against cancers.

Peptide nucleic acid (PNA) probe-based analysis to detect filaggrin mutations in atopic dermatitis patients.

Atopic dermatitis (AD) is a chronic inflammatory skin disease whose prevalence is increasing worldwide. Filaggrin (FLG) is essential for the development of the skin barrier, and its genetic mutations are major predisposing factors for AD. In this study, we developed a convenient and practical method to detect FLG mutations in AD patients using peptide nucleic acid (PNA) probes labelled with fluorescent markers for rapid analysis. Fluorescence melting curve analysis (FMCA) precisely identified FLG mutations based on the distinct difference in the melting temperatures of the wild-type and mutant allele. Moreover, PNA probe-based FMCA easily and accurately verified patient samples with both heterozygote and homozygote FLG mutations, providing a high-throughput method to reliable screen AD patients. Our method provides a convenient, rapid and accurate diagnostic tool to identify potential AD patients allowing for early preventive treatment, leading to lower incidence rates of AD, and reducing total healthcare expenses.

Pentaminomycins A and B, Hydroxyarginine-Containing Cyclic Pentapeptides from Streptomyces sp. RK88-1441.

Two new cyclic peptides, pentaminomycins A (1) and B (2), were isolated from cultures of Streptomyces sp. RK88-1441. Based on the interpretation of the NMR, UV, IR, and MS data, the planar structures of 1 and 2 were elucidated as cyclic pentapeptides with a modified amino acid residue, N5-hydroxyarginine (N5-OH-Arg). The absolute configurations of the constituent amino acid residues were determined by the advanced Marfey's method. Localization of l- and d-amino acids in the sequence was ascertained by chiral analysis of the fragment peptide obtained from a partial hydrolysate; amino acids were identified by LC-MS. Pentaminomycin A (1) reduced α-MSH-stimulated melanin synthesis by suppressing the expression of melanogenic enzymes including tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2).

Antibacterial Cyclic Lipopeptide Enamidonins with an Enamide-Linked Acyl Chain from a Streptomyces Species.

Three cyclic lipopeptides, including one known (1) and two new (2 and 3) compounds, that possess the rare enamide linkage group were discovered from Streptomyces sp. KCB14A132, an actinobacterium isolated from a soil sample collected from Jeung Island, Korea. The NMR and MS-based characterization showed that they differed in the amino acid residues in the peptide backbone. Application of Marfey's analysis, GITC derivatization, and modified Mosher's method, as well as ECD measurements provided the absolute configurations of enamidonin (1) and those of new compounds enamidonins B and C (2 and 3). The two new enamidonin analogues were shown to exhibit antibacterial activity against Gram-positive bacteria including methicillin-resistant and quinolone-resistant Staphylococcus aureus. Furthermore, evaluation of the extraction conditions and a close inspection of the LC-MS chromatograms revealed that the N, N-acetonide unit of the enamidonin family was formed during the acetone extraction process. The chemically prepared deacetonide derivatives of enamidonins were found to lack antibacterial activity, demonstrating that the dimethylimidazolidinone residue is necessary for antibacterial activity.

Genomics-Driven Discovery of Chlorinated Cyclic Hexapeptides Ulleungmycins A and B from a Streptomyces Species.

Analysis of the genome sequence of Streptomyces sp. KCB13F003 showed the presence of a cryptic gene cluster encoding flavin-dependent halogenase and nonribosomal peptide synthetase. Pleiotropic approaches using multiple culture media followed by LC-MS-guided isolation and spectroscopic analysis enabled the identification of two new chlorinated cyclic hexapeptides, ulleungmycins A and B (1 and 2). Their structures, including absolute configurations, were determined by 1D and 2D NMR techniques, advanced Marfey's analysis, and GITC derivatization. The new peptides, featuring unusual amino acids 5-chloro-l-tryptophan and d-homoleucine, exhibited moderate antibacterial activities against Gram-positive pathogenic bacteria including methicillin-resistant and quinolone-resistant Staphylococcus aureus.

Polyketides and Anthranilic Acid Possessing 6-Deoxy-α-l-talopyranose from a Streptomyces Species.

A bioassay-guided investigation in conjunction with chemical screening led to the isolation of three new glycosides, ulleungoside (1), 2-methylaminobenzoyl 6-deoxy-α-l-talopyranoside (2), and naphthomycinoside (3), along with three known secondary metabolites (5-7) from Streptomyces sp. KCB13F030. Their structures were elucidated by detailed NMR and MS spectroscopic analyses. Absolute configurational analysis of the sugar units based on the magnitudes of the coupling constants, NOESY correlations, chemical derivatization, and optical rotation measurements revealed that compounds 1-3 and 5 incorporate the rare deoxyhexose 6-deoxy-α-l-talopyranose. The absolute configuration of a polyketide extender unit of 3 was determined by applying the J-based configuration analysis and modified Mosher's method. Ulleungoside (1) and naphthomycin A (7) showed in vitro inhibitory effects against indoleamine 2,3-dioxygenase activity. Further bioevaluation revealed that compounds 1 and 7 had moderate antiproliferative activities against several cancer cell lines, and compounds 5 and 6, which are members of the piericidin family, induced autophagosome accumulation.

Stachybotrysin, an Osteoclast Differentiation Inhibitor from the Marine-Derived Fungus Stachybotrys sp. KCB13F013.

Two new phenylspirodrimane derivatives, stachybotrysin (1) and stachybotrylactone B (2), were isolated from the cultures of the marine-derived fungus Stachybotrys sp. KCB13F013. The structures were determined by analyzing the spectroscopic data (1D and 2D NMR and MS) and chemical transformation, including the modified Mosher's method and single-crystal X-ray structure analysis. Compound 1 exhibited an inhibitory effect on osteoclast differentiation in bone marrow macrophage cells via suppressing the RANKL-induced activation of p-ERK, p-JNK, p-p38, c-Fos, and NFATc1.

New Cyclic Lipopeptides of the Iturin Class Produced by Saltern-Derived Bacillus sp. KCB14S006.

Salterns, one of the most extreme natural hypersaline environments, are a rich source of halophilic and halotolerant microorganisms, but they remain largely underexplored ecological niches in the discovery of bioactive secondary metabolites. In continued efforts to investigate the metabolic potential of microbial populations from chemically underexplored sites, three new lipopeptides named iturin F1, iturin F2 and iturin A9 (1-3), along with iturin A8 (4), were isolated from Bacillus sp. KCB14S006 derived from a saltern. The structures of the isolated compounds were established by 1D-, 2D-NMR and HR-ESIMS, and their absolute configurations were determined by applying advanced Marfey's method and CD spectroscopy. All isolates exhibited significant antifungal activities against various pathogenic fungi and moderate cytotoxic activities toward HeLa and src(ts)-NRK cell lines. Moreover, in an in vitro enzymatic assay, compound 4 showed a significant inhibitory activity against indoleamine 2,3-dioxygenase.

Haenamindole, an unusual diketopiperazine derivative from a marine-derived Penicillium sp. KCB12F005.

During the chemical investigation of marine-derived fungus, an unusual diketopiperazine (DKP) alkaloid, haenamindole (1), was isolated from a culture of the marine-derived fungus Penicillium sp. KCB12F005. The structure of 1, which possesses benzyl-hydroxypiperazindione and phenyl-pyrimidoindole rings system in the molecule, was elucidated by analysis of NMR and MS data. The stereochemistry of 1 was determined by ROESY and advanced Marfey's method.

A chrysin derivative suppresses skin cancer growth by inhibiting cyclin-dependent kinases.

Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P(+) cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P(+) cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency.

Illudins C2 and C3 stimulate lipolysis in 3T3-L1 adipocytes and suppress adipogenesis in 3T3-L1 preadipocytes.

The secondary metabolites illudins C2 (1) and C3 (2), obtained from the culture broth of Coprinus atramentarius, have been shown to possess antimicrobial activity. In the present study, we discovered novel biological activities of 1 and 2 in lipolysis of differentiated 3T3-L1 adipocytes and adipogenesis of 3T3-L1 preadipocytes. Compounds 1 and 2 exhibit a dose-dependent increase in glycerol release and thereby reduce intracellular lipid accumulation. The stimulatory effects of 1 and 2 on lipolysis are prevented by cAMP-dependent protein kinase (PKA) and extracellular signal-regulated kinase (ERK) inhibitors. Compounds 1 and 2 down-regulated perilipin and also affected the mRNA and protein levels of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL). However, 1 and 2 treatment leads to a significant increase in PKA-mediated phosphorylation of HSL at S563 and S660. In addition, 1 and 2 treatment in 3T3-L1 preadipocytes induces down-regulation of the critical transcription factors, CCAAT/enhancer binding protein α and ß (C/EBPα and C/EBPß), and peroxisome proliferator activated receptor γ (PPARγ), which are required for adipogenesis, and accordingly inhibits adipogenesis. These results suggest that 1 and 2 might be useful for treating obesity due to their modulatory effects on fat by affecting adipocyte differentiation and fat mobilization.

HIF-1α inhibition by MO-2097, a novel chiral-free benzofuran targeting hnRNPA2B1.

INTRODUCTION: Hypoxia-inducible factor 1 (HIF-1) is a transcriptional activator mediating adaptive responses to hypoxia. It is up-regulated in the tumor microenvironment and recognized as an effective anticancer drug target. Previously, we discovered that the natural compound moracin-O and its synthetic derivative MO-460 inhibited HIF-1α via hnRNPA2B1. OBJECTIVES: This study aimed to develop novel HIF-1 inhibitors for cancer chemotherapy by harnessing the potential of the natural products moracins-O and P. METHODS: In an ongoing search for novel HIF-1 inhibitors, a series of nature-inspired benzofurans with modifications on the chiral rings of moracins-O and P were synthesized. They showed improved chemical tractability and were evaluated for their inhibitory activity on HIF-1α accumulation under hypoxic conditions in HeLa CCL2 cells. The most potent derivative's chemical-based toxicities, binding affinities, and in vivo anti-tumorigenic effects were evaluated. Further, we examined whether our compound, MO-2097, exhibited anticancer effects in three-dimensional cultured organoids. RESULTS: Herein, we identified a novel synthetic chiral-free compound, MO-2097, with reduced structural complexity and increased efficiency. MO-2097 exhibited inhibitory effects on hypoxia-induced HIF-1α accumulation in HeLa CCL2 cells via inhibition of hnRNPA2B1 protein, whose binding affinities were confirmed by isothermal titration calorimetry analysis. In addition, MO-2097 demonstrated in vivo efficacy and biocompatibility in a BALB/c mice xenograft model. The immunohistochemistry staining of MO-2097-treated tissues showed decreased expression of HIF-1α and increased levels of apoptosis marker cleaved caspase 3, confirming in vivo efficacy. Furthermore, we confirmed that MO-2097 works effectively in cancer patient-based organoid models. CONCLUSION: MO-2097 represents a promising new generation of chemotherapeutic agents targeting HIF-1α inhibition via hnRNPA2B1, requiring further investigation.

Near-Infrared Fluorescence Probe for Specific Detection of Acetylcholinesterase and Imaging in Live Cells and Zebrafish.

Acetylcholinesterase (AChE) is a pivotal enzyme that is closely related with multiple neurological diseases, such as brain disorders or alterations in the neurotransmission and cancer. The development of convenient methods for imaging AChE activity in biological samples is very important to understand its mechanisms and functions in a living system. Herein, a fluorescent probe exhibiting emission in the near-infrared (NIR) region is developed to detect AChE and visualize biological AChE activities. This probe exhibits a quick response time, reasonable detection limit, and a large Stokes shift accompanied by the NIR emission. The probe has much better reactivity toward AChE than butyrylcholinesterase, which is one of the significant interfering substances. The outstanding specificity of the probe is proved by cellular imaging AChE activity and successful mapping in different regions of zebrafish. Such an effective probe can greatly contribute to ongoing efforts to design emission probes that have distinct properties to assay AChE in biological systems.

Dutomycin Induces Autophagy and Apoptosis by Targeting the Serine Protease Inhibitor SERPINB6.

Autophagy plays an important role in maintaining tumor cell progression and survival in response to metabolic stress. Thus, the regulation of autophagy can be used as a strategy for anticancer therapy. Here, we report dutomycin (DTM) as a novel autophagy enhancer that eventually induces apoptosis due to excessive autophagy. Also, human serine protease inhibitor B6 (SERPINB6) was identified as a target protein of DTM, and its novel function which is involved in autophagy was studied for the first time. We show that DTM directly binds SERPINB6 and then activates intracellular serine proteases, resulting in autophagy induction. Inhibitory effects of DTM on the function of SERPINB6 were confirmed through enzyme- and cell-based approaches, and SERPINB6 was validated as a target protein using siRNA-mediated knockdown and an overexpression test. In a zebrafish xenograft model, DTM showed a significant decrease in tumor area. Furthermore, the present findings will be expected to contribute to the expansion of novel basic knowledge about the correlation of cancer and autophagy by promoting active further research on SERPINB6, which was not previously considered the subject of cancer biology.

Evaluation of human neutrophil elastase inhibitory effect of iridoid glycosides from Hedyotis diffusa.

Five iridoid glycosides were isolated from the MeOH extract of Hedyotis diffusa, and their structures were elucidated as E-6-O-p-methoxycinnamoyl scandoside methyl ester (1), Z-6-O-p-methoxycinnamoyl scandoside methyl ester (2), E-6-O-p-feruloyl scandoside methyl ester (3), E-6-O-p-coumaroyl scandoside methyl ester (4), and Z-6-O-p-coumaroyl scandoside methyl ester (5) by interpretation of their spectroscopic data. All the isolated compounds were evaluated for human neutrophil elastase inhibitory effect, and compound 1 showed potent activity with an IC(50) value of 18.0muM. The molecular docking simulation suggested a structural model for the inhibition of human neutrophil elastase by compound 1.

Secondary metabolites of Volvariella bombycina and their inhibitory effects on melanogenesis.

Four compounds were isolated from the broth culture of Volvariella bombycina and they were identified as ergosta-4,6,8(14),22-tetraene-3-one (1), ergosterol peroxide (2), indole-3-carboxaldehyde (3) and indazole (4) by interpretation of spectroscopic data. Among them, compound 2 exhibited melanogenesis inhibitory effect in cultured B16 mouse melanoma cells.

Hydoroxyhibiscone A, a novel human neutrophil elastase inhibitor from Hibiscus syriacus.

In an ongoing investigation of compounds from natural products that exhibit anti-aging properties, hydroxyhibiscone A (1), a new furanosesquiterpenoid, together with hibiscone D (2), was isolated from the root bark of Hibiscus syriacus. Utilizing UV, IR, NMR, and MS spectroscopic analyses, these chemical structures were revealed. Compounds 1 and 2 were found to possess significant anti-aging properties on the human neutrophil elastase (HNE) assay, exhibiting HNE inhibitory activities with IC50 values of 5.2 and 4.6 micronM, respectively.

Kushenol E inhibits autophagy and impairs lysosomal positioning via VCP/p97 inhibition.

Autophagy plays a major role in cell survival and has therefore been exploited as an important strategy in cancer therapy. In this study, we evaluated the autophagy-regulatory effects of kushenol E (KE), a bi-prenylated flavonoid isolated from Sophora flavescens and found that KE increased LC3B-II levels while inducing the formation of autophagic vacuoles and immature autophagosomes in HeLa and HCT116 cells. Transmission electron microscopy images revealed that KE treatment generates immature autophagosomes. Furthermore, KE inhibited autophagosome maturation as demonstrated by blocking the degradation of EGFP puncta in HeLa cells stably expressing EGFP-mRFP-LC3B. It also reduced lysosomal activity and cathepsin maturation by disrupting lysosomal positioning, subsequently inducing apoptosis. Further, a combinatorial approach employing cellular thermal shift assays, revealed valosin-containing protein (VCP)/p97 as a potential target protein of KE; the knockdown and overexpression of VCP/p97 confirmed its involvement in regulating lysosomal positioning for autophagy maturation via direct interactions with KE. Thus, KE may possess autophagy-regulating properties mediated by binding to VCP/p97.

Inhibition of osteoclasts differentiation by CDC2-induced NFATc1 phosphorylation.

Bone homeostasis is regulated by a balance of bone formation and bone resorption; dysregulation of bone homeostasis may cause bone-related diseases (e.g., osteoporosis, osteopetrosis, bone fracture). Members of the nuclear factor of activated T cells (NFAT) family of transcription factors play crucial roles in the regulation of immune system, inflammatory responses, cardiac formation, skeletal muscle development, and bone homeostasis. Of these, NFATc1 is a key transcription factor mediating osteoclast differentiation, which is regulated by phosphorylation by distinct NFAT kinases including casein kinase 1 (CK1), glycogen synthase kinase 3 (GSK3), and dual-specificity tyrosine-phosphorylation-regulated kinases (DYRKs). In this study, we report that cell division control protein 2 homolog (cdc2) is a novel NFAT protein kinase that inhibits NFATc1 activation by direct phosphorylation of the NFATc1 S263 residue. Cdc2 inhibitors such as Roscovitine and BMI-1026 induce reduction of phosphorylation of NFATc1, and this process leads to the inhibition of NFATc1 translocation from the nucleus to the cytoplasm, consequently increasing the nuclear pool of NFATc1. Additionally, the inhibition of cdc2-mediated NFATc1 phosphorylation causes an elevation of osteoclast differentiation or TRAP-positive staining in zebrafish scales. Our results suggest that cdc2 is a novel NFAT protein kinase that negatively regulates osteoclast differentiation.