Highly potent growth hormone secretagogues

During an effort to search for more potent growth hormone secretagogues, we discovered a class of compounds of which the best compound 8 was 7-fold more active in vitro than the best compound in the series we revealed before [Tata, J. R.; Lu, Z.; Jacks, T. M.; Schleim, K. D.; Cheng, K.; Wei, L.; Chan, W.-S.; Butler, B.; Tsou, N.; Leung, K.; Chiu, S.-H. L.; Hickey, G. J.; Smith, R. G.; Patchett, A. A. Bioorg. Med. Chem. Lett.1997, 7, 2319.]. Animal studies show that compound 8 can stimulate growth hormone release at the oral dose as low as 0.06 mpk. Chemistry and biological studies are discussed.     

Synthesis of 2',3'-dideoxy-2'-fluoro-3'-thioarabinothymidine and its 3'-phosphoramidite derivative

An efficient method for the synthesis of 5'-O-monomethoxytrityl-2',3'-dideoxy-2'-fluoro-3'-thioarabinothymidine [(5'MMT)araF-T(3'SH), (5)] and its 3'-phosphoramidite derivative (6) suitable for automated incorporation into oligonucleotides, is demonstrated. A key step in the synthesis involves reaction of 5'-O-MMT-2,3'-O-anhydrothymidine (4) (Eleuteri, A.; Reese, C.B.; Song, Q. J. Chem. Soc. Perkin Trans. 1 1996, 2237 pp.) with sodium thioacetate to give (5'-MMT)araF-T(3'SAc) (5) (Elzagheid, M.I.; Mattila, K.; Oivanen, M.; Jones, B.C.N.M.; Cosstick, L?nnberg, H. Eur. J. Org. Chem. 2000, 1987-1991). This nucleoside was then converted to its corresponding phosphoramidite derivative, 6, as described previously ((a) Sun, S.; Yoshida, A.; Piccirilli, J.A. RNA, 1997, 3, 1352-1363; (b) Matulic-Adamic, J.; Beigelman, L. Helvetica Chemica Acta 1999, 82, 2141-2150: (c) Fettes, K.J.; O'Neil, I.; Roberts, S.M.; Cosstick, R. Nucleosides, Nucleotides and Nucl. Acids 2001, 20, 1351-1354).     

Metronidazole acid acyl sulfonamide: a novel class of anticancer agents and potential EGFR tyrosine kinase inhibitors

A series of novel metronidazole derivatives were recently reported as potent anticancer agents targeting EGFR and HER-2 by our group [Qian, Y.; Zhang, H. J.; Zhang, H.; Xu, C.; Zhao, J.; Zhu, H. L. Bioorg. Med. Chem.2010, 18, 4991]. Based on the previous results, we designed and synthesized a new series of metronidazole acid acyl sulfonamide derivatives and a new series of phenylacetyl benzenesulfonamide derivatives and their anticancer activities were evaluated as potential EGFR and HER-2 kinase inhibitors. Among all the compounds, compound 12 displayed the most potent inhibitory activity EGFR and HER-2 (IC(50)=0.39 μM for EGFR and IC(50)=1.53 μM for HER-2) and it also showed the most potent growth inhibitory activity against A549 and B16-F10 cancer cell line in vitro, with an IC(50) value of 1.26 μg/mL for A549 and 0.35 μg/mL for B16-F10. Docking simulation was further performed to position compound 12 into the EGFR active site to determine the probable binding model.     

A new concept for DNA-arrays

We will insert a cleavage site in an oligodeoxynucleotide, which can be used for a selective and quantitative cleavage. For that reason we synthesized the four 5'-S-(4,4'-dimethoxytrityl)-mercapto-2'-deoxynucleotide-3'-O-(2-cyanoethoxydiisopropylamino)-phosphites (5a-d). The cleavage of P-S and C-S bonds is described (Mag, M.; Lücking, S.; Engels, J.W. Synthesis and selective cleavage of an oligodeoxy-nucleotide containing a bridged internucleotide 5'-phosphorthioate linkage. Nucleic Acids Res. 1991, 19 (7), 1437-1441; Marriott, J.H.; Mottahedeh, M.; Reese, C.B. 9-(4-methoxyphenyl)xanthen-9-thiol: A useful reagent for the preparation of thiols. Tetrahedron Lett. 1990, 31 (51), 7485-7488; Divakar, K.J.; Mottoh, A.; Reese, C.B.; Shanghvi, Y.S. Approaches to the synthesis of 2' thio analogues of pyrimidine ribosides. J. Chem. Sc., Perkin Trans. 1 1990, 969-974). The oligodeoxynucleotides with an achiral bridged 5'-phosphorothioate linkage 5'-O-P-S-3' are synthesized by the phosphoramidite procedure.     

Enaminones 10. Molecular modeling aspects of the 5-methylcyclohexenone derivatives

This article expands upon our original submission to the Eddington, N. D.; Cox, D. S.; Khurana, M.; Salama, N. N.; Stables, J. P.; Harrison, S. J.; Negussie, A.; Taylor, R. S.; Tran, U. Q.; Moore, J. A.; Barrow, J. C.; Scott, K. R. Eur. J. Med. Chem. 2003, 38, 49 on a series of twenty (20) compounds, all 5-methyl-3-[(substituted)-phenylamino]-cyclohex-2-enone derivatives. This article provides the reasons why the compounds are active/inactive. By use of computational methods, the reasons for activity/inactivity are explained.     

Functional anthology of intrinsic disorder. 3. Ligands, post-translational modifications, and diseases associated with intrinsically disordered proteins

Currently, the understanding of the relationships between function, amino acid sequence, and protein structure continues to represent one of the major challenges of the modern protein science. As many as 50% of eukaryotic proteins are likely to contain functionally important long disordered regions. Many proteins are wholly disordered but still possess numerous biologically important functions. However, the number of experimentally confirmed disordered proteins with known biological functions is substantially smaller than their actual number in nature. Therefore, there is a crucial need for novel bionformatics approaches that allow projection of the current knowledge from a few experimentally verified examples to much larger groups of known and potential proteins. The elaboration of a bioinformatics tool for the analysis of functional diversity of intrinsically disordered proteins and application of this data mining tool to >200 000 proteins from the Swiss-Prot database, each annotated with at least one of the 875 functional keywords, was described in the first paper of this series (Xie, H.; Vucetic, S.; Iakoucheva, L. M.; Oldfield, C. J.; Dunker, A. K.; Obradovic, Z.; Uversky, V.N. Functional anthology of intrinsic disorder. 1. Biological processes and functions of proteins with long disordered regions. J. Proteome Res. 2007, 5, 1882-1898). Using this tool, we have found that out of the 710 Swiss-Prot functional keywords associated with at least 20 proteins, 262 were strongly positively correlated with long intrinsically disordered regions, and 302 were strongly negatively correlated. Illustrative examples of functional disorder or order were found for the vast majority of keywords showing strongest positive or negative correlation with intrinsic disorder, respectively. Some 80 Swiss-Prot keywords associated with disorder- and order-driven biological processes and protein functions were described in the first paper (see above). The second paper of the series was devoted to the presentation of 87 Swiss-Prot keywords attributed to the cellular components, domains, technical terms, developmental processes, and coding sequence diversities possessing strong positive and negative correlation with long disordered regions (Vucetic, S.; Xie, H.; Iakoucheva, L. M.; Oldfield, C. J.; Dunker, A. K.; Obradovic, Z.; Uversky, V. N. Functional anthology of intrinsic disorder. 2. Cellular components, domains, technical terms, developmental processes, and coding sequence diversities correlated with long disordered regions. J. Proteome Res. 2007, 5, 1899-1916). Protein structure and functionality can be modulated by various post-translational modifications or/and as a result of binding of specific ligands. Numerous human diseases are associated with protein misfolding/misassembly/misfunctioning. This work concludes the series of papers dedicated to the functional anthology of intrinsic disorder and describes approximately 80 Swiss-Prot functional keywords that are related to ligands, post-translational modifications, and diseases possessing strong positive or negative correlation with the predicted long disordered regions in proteins.     

Isolation and functional analysis of a chk2 homologue from Entamoeba histolytica

Mammalian Chk2 is a Ser/Thr kinase required for cell-division arrest induced by DNA damage. We found six new kinase genes of Entamoeba histolytica by analysis in silico. One of the kinase genes was a homologue of human chk2 gene. The chk2 homologue gene (Eh chk2) was expected to encode 398 amino acids and showed nearly 50% homology to human Chk2 in amino acid sequence. Eh chk2 had a catalytic domain of Ser/Thr kinase and a fork head-associated (FHA) domain that is highly conserved among Chk2 homologues in vertebrates. To examine the biological functions of Eh chk2, we synthesized Eh chk2 mRNA in vitro and injected it into immature frog eggs (Xenopus laevis oocytes) as a model system of cell division. Eh chk2 markedly delayed the cell division of frog eggs by disrupting transition of G2 phase to M phase. Eh chk2 also inhibited the activation of p42 MAPK and Cdc2 kinase which are representative events induced by cell division. These results suggest that Eh chk2 gene should be a cell-division regulator in E. histolytica.     

Synthesis of 2′,3′-Dideoxy-2′-fluoro-3′-thioarabinothymidine and Its 3′-Phosphoramidite Derivative

Abstract

An efficient method for the synthesis of 5′-O-monomethoxytrityl-2′,3′-dideoxy-2′-fluoro-3′-thioarabinothymidine [^5′-MMTaraF-T_3′SH, (5)] and its 3′-phosphoramidite derivative (6) suitable for automated incorporation into oligonucleotides, is demonstrated. A key step in the synthesis involves reaction of 5′-O-MMT-2,3′-O-anhydrothymidine (4) (Eleuteri, A.; Reese, C.B.; Song, Q., J. Chem. Soc. Perkin Trans. 1 1996, 2237 pp.) with sodium thioacetate to give ^5′-MMTaraF-T_3′SAc (5) (Elzagheid, M.I.; Mattila, K.; Oivanen, M.; Jones, B.C.N.M.; Cosstick, Lönnberg, H. Eur. J. Org. Chem. 2000, 1987–1991). This nucleoside was then converted to its corresponding phosphoramidite derivative, 6, as described previously ((a) Sun, S.; Yoshida, A.; Piccirilli, J.A. RNA, 1997, 3, 1352–1363; (b) Matulic-Adamic, J.; Beigelman, L. Helvetica Chemica Acta 1999, 82, 2141–2150; (c) Fettes, K.J.; O’Neil, I.; Roberts, S.M.; Cosstick, R. Nucleosides, Nucleotides and Nucl. Acids 2001, 20, 1351–1354).     

BUCHBESPRECHUNGEN

Book reviewed in this article:
reviews type of article–
M ason , J. L. (ed.): Evolution of domesticated animals . London, New York: Longman 1984.
G riffiths , G. C. D. (ed.): Flies of the Nearctic Region . Vol. VIII: Cyclorrhapha II (Schizophora: Calyptratae), Part 2 Anthomyiidae, Number 1 by G. C. D. G riffiths . Stuttgart: E. Schweitzerbart'sche Verlagsbuchhandlung 1982.
S impson , G. G.: Penguins . Past and Present, Here and There. New Haven and London: Yale University Press 1983.
G ans , E.; P ouch , F. H. (eds.): Biology of the Reptilia . Vol. 12. New York – London: Academic Press 1982. 564 S. DM 353,–. G ans , E. (ed.):
M atsuno , K.; D ose , K.; H arada , K.; R ohlfing , D. L. (eds.): Molecular Evolution and Protobiology . New York, London
F elsenstein , J. (ed.): Numerical Taxonomy . Nato AS1 Series. Series G Ecological Sciencesxs
S meets , W. J. A. J.; N ieuwenhuys , R.; R oberts , B. L.: The Central Nervous System of Cartilaginous Fishes . Structure and Functional Correlations. Berlin, Heidelberg, New York: Springer 1983
H echt , M. K.; W allace , B.; P range , G. T. (eds.): Evolutionary Biology . Vol. 18. New York and London     

Influence of chk1 and plk1 silencing on radiation- or cisplatin-induced cytotoxicity in human malignant cells

The G2/M checkpoint is an attractive pathway for targeting and sensitizing tumor cells to cancer treatment. Abrogation of the G2/M checkpoint by targeting molecules, such as checkpoint kinase 1 (chk1), increases DNA breakage and sensitizes tumor cells to anti-tumoral agents. However, most of the previously described G2/M abrogators are actually targeting the G2-M border checkpoints rather than mitotic checkpoints. This prompted us to test the effects of combined targeting of chk1 and a critical regulator of mitosis, polo-like kinase 1 (plk1). Chk1 and plk1 were found to be co-expressed in 70% of primary neoplastic tissues we examined. Asynchronized tumor cells were treated with different DNA damaging-agents to activate G1/S, S or G2/M checkpoints. Either chk1 or plk1-specific antisense oligodeoxynucleotides (ASODN) enhanced DNA damaging agent-induced apoptosis. When used in combination, however, chk1- plus plk1-specific ASODN failed to produce synergistic effects. Moreover, selective targeting of plk1 or chk1 in tumor xenografts of mice by oncolytic adenovirus mutants demonstrated potent anti-tumoral efficacy in the presence of low dose cisplatin. Again, combined targeting of chk1 and plk1 did not further enhance anti-tumoral efficacy. We concluded that combined targeting of chk1 and plk1 was not superior to either targeting chk1 or plk1 alone, which suggested that chk1 and plk1 silencing might overlap in their mechanism of action. Whether combined targeting of chk1 with other, more specific mitotic regulators would synergistically sensitize tumor to anti-neoplastic therapeutics needs to be further clarified. Qinglei Gao and Xiaoyuan Huang contributed equally to this work.     

Potent and selective neuronal nitric oxide synthase inhibitors with improved cellular permeability

Recently, a series of potent and selective neuronal nitric oxide synthase inhibitors containing two basic nitrogen atoms was reported (Ji, H.; Stanton, B. Z.; Igarashi, J.; Li, H.; Martásek, P.; Roman, L. J.; Poulos, T. L.; Silverman, R. B. J. Am. Chem. Soc. 2008, 130, 3900–3914). In an effort to improve their bioavailability, three compounds (2a–c) were designed with electron-withdrawing groups near one of the basic nitrogen atoms to lower its pK_a. Inhibition studies with these compounds showed that two of them not only retained most of the potency and selectivity of the best analogue of the earlier series, but also showed improved membrane permeability based on data from a cell-based assay.     

Glu375Gln and Asp225Val mutants: about the nature of the covalent linkages between heme group and apo-Protein in bovine lactoperoxidase

In analogy with studies previously reported for myeloperoxidase (Kooter, I. M.; Moguilevsky, N.; Bollen, A.; Van der Veen, L. A.; Otto, C.; Dekker, H. L.; Wever, R. J. Biol. Chem. 1999, 274, 26794), we examined for bovine lactoperoxidase the effect of mutation of Asp225 and Glu375, the residues thought to be responsible for the covalent binding of the heme group to the apoprotein. Starting from the plasmid encoding rbLPO (Watanabe, S.; Varsalona, F.; Yoo, Y.; Guillaume, J. P.; Bollen, A.; Shimazaki, K.; Moguilevsky, N. FEBS Letters 1998, 441, 476), which was engineered to carry mutations in correspondence of those residues, the mutants Asp225Val and Glu375Gln were expressed in CHO cells and their products purified and characterized. Unequivocal evidence about the existence of ester linkages as well as their relative contribution to the specific spectroscopic and catalytic properties of bLPO is here discussed.     

Structure–activity relationships and in vivo activity of (1H-pyrazol-4-yl)acetamide antagonists of the P2X7 receptor

Structure–activity relationships (SAR) of analogues of lead compound 1 were investigated and compound 16 was selected for further study in animal models of pain. Compound 16 was shown to be a potent antihyperalgesic agent in both the rat acute complete Freund’s adjuvant (CFA) model of inflammatory pain [Iadarola, M. J.; Douglass, J.; Civelli, O.; Naranjo, J. R. rain Res. 1988, 455, 205] and the knee joint model of chronic inflammatory pain [Wilson, A. W.; Medhurst, S. J.; Dixon, C. I.; Bontoft, N. C.; Winyard, L. A.; Brackenborough, K. T.; De Alba, J.; Clarke, C. J.; Gunthorpe, M. J.; Hicks, G. A.; Bountra, C.; McQueen, D. S.; Chessell, I. P. Eur. J. Pain 2006, 10, 537].     

Books Reviews

Book reviewed in this article:
NOE-NYGAARD N.: Ecological, sedimentary, and geoshemical evolution of the late-glacial to postglacial hose lacustrine basin, Denmark.
BUTERL˜ELD, N. J.; KNOLL, A. H.; SWETT, K.: Paleobiology of the Neoproterozoic Svanbergfjellet Formation, Spitsbergen.
POPOV, L.; HOLMER, L.: Cambrian-Ordovician lingulate brachiopods from Scandinavia, Kazakhstan, and South Ural Mountains.
LILJEDAHL, L.: Silurian nuculoid and modiomorphid bivalves from Sweden.     

p56(chk1) protein kinase is required for the DNA replication checkpoint at 37 degrees C in fission yeast.

Fission yeast p56(chk1) kinase is known to be involved in the DNA damage checkpoint but not to be required for cell cycle arrest following exposure to the DNA replication inhibitor hydroxyurea (HU). For this reason, p56(chk1) is considered not to be necessary for the DNA replication checkpoint which acts through the inhibitory phosphorylation of p34(cdc2) kinase activity. In a search for Schizosaccharomyces pombe mutants that abolish the S phase cell cycle arrest of a thermosensitive DNA polymerase delta strain at 37 degrees C, we isolated two chk1 alleles. These alleles are proficient for the DNA damage checkpoint, but induce mitotic catastrophe in several S phase thermosensitive mutants. We show that the mitotic catastrophe correlates with a decreased level of tyrosine phosphorylation of p34(cdc2). In addition, we found that the deletion of chk1 and the chk1 alleles abolish the cell cycle arrest and induce mitotic catastrophe in cells exposed to HU, if the cells are grown at 37 degrees C. These findings suggest that chk1 is important for the maintenance of the DNA replication checkpoint in S phase thermosensitive mutants and that the p56(chk1) kinase must possess a novel function that prevents premature activation of p34(cdc2) kinase under conditions of impaired DNA replication at 37 degrees C.     

Book Reviews

Zoophysiology. Coordinating Editor: F arner , D. S. Editors: H einrich , B.; H oar , W. S.; J ohansen , K.; L anger , H.; N euweiler , G.; R andall , D. J. Vol. 17: S mith , R. J. F.: The Control of Fish Migration. .
Systematische Zoologie. Begründet von A dolf R emane , V olker S torch und U lrich W elsch . Fortgeführt von Prof. Dr. V olker S torch , Zoologisches Institut der Universität Heidelberg, und Prof. Dr. Dr. U lrich W elsch , Anatomische Anstalt der Universität München.     

BUCHBESPRECHUNGEN

N ei , M.: Molecular Evolutionary Genetics .
B radbury , J. W.; A ndersson , M. B. (Eds.): Sexual Selection: Testing the Alternatives .
B otosaneanu , L. (Ed.): Stygofauna Mundi . A Faunistic, Distributional and Ecological Synthesis of the World Fauna inhabiting Subterranean Waters (including the Marine Interstitial).
E ndler , J. A.: Natural Selection in the Wild . Monographs in Population Biology 21.
R uttner , F.: Biogeography and taxonomy of honeybees . Berlin–Heidelberg–New York–London–Paris–Tokyo
M engel , K.: Einführung in die Biochemie . 3., vollst. bearb. u. erweit. Aufl., Giessen: Verlag der Ferber'schen Universitätsbuchhandlung 1988.
K ämpfe , C.; K ittel , R.; K lapperstück , J.: Leitfaden der Anatomie der Wirbeltiere.     

BUCHBESPRECHUNGEN

T uck , G. S.; H einzel , H.: Die Meeresvögel der Welt. Ein Taschenbuch für Ornithologen und Naturf reunde. Aus dem Englischen übers. u. bearb. von E lisabeth und Dr. H. G oethe
K nussmann , R.: Vergleichende Biologie des Menschen
K aestner , A. (Begründer): Lehrbuch der speziellen Zoologie. Band I: Wirbellose Tiere. Herausgegeben von H ans -E ckhard G runer
H eberer , G.: Allgemeine Abstammungslehre. 2., neu bearb. und erweit. Aufl. von B. Z epernick
M oore , W. J.: The Mammalian Skull. Biological Structure and Function 8
R andall , D. J.; B urggren , W. W.; F arrell , A. P.; H aswell , M. S.: The evolution of air breathing in vertebrates
S auer , H. W.: Entwicklungsbiologie. Ansätze zu einer Synthese. Mit einem Geleitwort vonF. S eidel . Hochschultext
H ardisty , M. W.: Biology of the Cyclostomes. (Biologie der Cyclostomen). London: Chapman and Hall 1979. XIV, 428 S., zahlreiche Abb., graph
W eick , F.: Die Greifvögel der Welt. Ein farbiger Führer zur Bestimmung der Ordnung Fakoniformes. Unter Mitarbeit von L. H. B rown , Karen, Kenia. Hamburg und Berlin
A pfelbach , R.; D öhl , J.: Verhaltensforschung. 3., neubearb. u. erw. Aufl
H ennig , W illi : Phylogenetische Systematik. Hrsg. Prof. Dr. W olfgang H ennig
K ämpfe , L.; K ittel , R.; K lapperstück , J.: Leitfaden der Anatomie der Wirbeltiere. 4.,überarb     

Estrogen pyrazoles: defining the pyrazole core structure and the orientation of substituents in the ligand binding pocket of the estrogen receptor

Previously, we reported that certain tetrasubstituted 1,3,5-triaryl-4-alkyl-pyrazoles bind to the estrogen receptor (ER) with high affinity (Fink, B. E.; Mortenson, D. S.; Stauffer, S. R.; Aron, Z. D.; Katzenellenbogen, J. A. Chem. Biol. 1999, 6, 205-219; Stauffer, S. R.; Katzenellenbogen, J. A. J. Comb/. Chem. 2000, 2. 318 329; Stauffer, S. R.: Coletta, C. J.: Sun, J.; Tedesco, R., Katzenellenbogen, B. S.; Katzenellenbogen, J. A. J. Med. Chem. 2000, submitted). To investigate how cyclic permutation of the two nitrogen atoms of a pyrazole might affect ER binding affinity, we prepared a new pyrazole core isomer, namely a 1,3,4-triaryl-5-alkyl-pyrazole (2), to compare it with our original pyrazole (1). We also prepared several peripherally matched core pyrazole isomer sets to investigate whether the two pyrazole series share a common binding orientation. Our efficient, regioselective synthetic route to these pyrazoles relies on the acylation of a hydrazone anion, followed by cyclization, halogenation, and Suzuki coupling. We found that the ER accommodates 1,3,4-triaryl-pyrazoles of the isomeric series only somewhat less well than the original 1,3,5-triaryl series, and it appears that both series share a common binding mode. This preferred orientation for the 1,3,5-triaryl-4-alkyl-pyrazoles is supported by binding affinity measurements of analogues in which the phenolic hydroxyl groups were systematically removed from each of the three aryl groups, and the orientation is consistent, as well, with molecular modeling studies. These studies provide additional insight into the design of heterocyclic core structures for the development of high affinity ER ligands by combinatorial methods.