Drug design and discovery最新文献

A useful calmodulin (CaM) antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), was invented by Hidaka et al. in 1978 (J. Pharmacol. Exp. Ther. 207, 8-15). Here, we have designed new CaM antagonists on the basis of the three-dimensional structure of Ca2+/CaM complexed with W-7. Eleven new compounds all share a similar architecture, in which two W-7 molecules are linked between their aminohexyl termini by a linker with different functionalities. A wide range of inhibitory activities against Ca2+/CaM-dependent protein kinase I (CaM kinase I) has been observed with these self-crosslinked W-7 analogs, (W-7)2. In vitro competitive CaM kinase I assays using CaM kinase I and nuclear magnetic resonance studies indicated that one (W-7)2 molecule binds to one CaM molecule as expected, with the two chloronaphthalene rings of (W-7)2 being anchored separately to the N- and C-terminal hydrophobic pockets of Ca2+/CaM. The most potent compound, N,N'-bis[6-(5-chloro-1-naphthalenesulfonyl)-amino-1-hexyl]-p-xylen e-diamine ((W-7)2 - 10), inhibits CaM kinase I activity at an IC50 value of 0.23 microM; about 75 times more effectively than W-7. The length and basicity of the linker sequence in (W-7)2 significantly contribute to inhibitory activity. The present study opens an avenue for developing powerful CaM antagonists that could be used at low doses in vivo.

A three dimensional combinatorial library of 3-halogen-4-amino-5-alkoxy-2(5H)-furanones has been prepared by applying solution phase combinatorial chemistry techniques. The substituents in the 3-4-5-positions of a butenolide scaffold were varied independently to generate with 3 butenolides, 4 alcohols and 24 amines a library of 288 compounds using a 2 stage synthetic protocol. Typical representives of the library were purified and fully characterized. Biological evaluation resulted in the discovery of a lead structure for a new class of antibiotic agents. The 4-benzylamino-2(5H)-furanone, Dr, of this library has shown a promising antibiotic activity against the multiresistant Staphillococcus aureus (MRSA 96-7778).

A free diazafluorenyl radical based on the Koelsch free radical was designed and synthesized with expectations of stability and water solubility. The novel radical precursors were synthesised from the parent brominated stilbene and the substituted fluorenes in an IPSO substitution, as a key synthetic step. The precursors were deprotonated and the anion was discharged by an aqueous solution of potassium cyanoferrate. The new radicals were prepared from fluorene in 6 steps with good overall yields. These radicals have shown promising anticancer activity in initial screenings on 2 different MAC cell lines.

Radiolabeled ZM 241385 (4-(2-[7-amino-2- ¿furyl¿¿1,2,4¿triazolo¿2,3-a¿¿1,3,5¿triazin-5-ylaminoethyl)p henol), has previously been used as a high affinity radioligand for the labeling of A2A adenosine receptors in cell membranes. Another subtype, the A2B receptor, is the least well-defined subtype of adenosine receptors and lacks selective pharmacological probes. In the present study, we have used [3H]ZM 241385 as a radioligand to label recombinant human A2B adenosine receptors in HEK-293 cell membranes, that do not express A2A adenosine receptors, and found that the pharmacological profile is consistent with the SAR of A2B receptors. Saturable, specific binding (Kd 33.6 nM, Bmax 4.48 pmol/mg protein) that was best described by a one-site model was found, and specific binding was approximately 75% of total binding. [3H]ZM 241385 binding was displaceable by a large number of compounds known to interact with A2B receptors; thus, this method has promise as a tool in the search for agonists and antagonists selective for this subtype. Xanthine analogs, which are antagonists, proved to be the most potent displacers. The Ki of XAC, xanthine amine congener, was 12.3 nM, while CPX (8-cyclopentyl-1,3-dipropylxanthine) was less potent. The non-selective triazoloquinazoline antagonist CGS 15943 (Ki 16.4 nM), which is similar in structure to ZM 241385, was slightly less potent than XAC. The non-xanthine A2B-antagonist alloxazine displaced [3H]ZM 241385-binding with a Ki of 462 nM, similar to its affinity in functional assays. Adenosine derivatives known to activate this receptor subtype, such as NECA (5'-N-ethylcarboxamidoadenosine) and R-PIA (N6-phenylisopropyladenosine), were considerably less potent than the 8-substituted xanthines examined.

A new series of 5-substituted and 5-nonsubstituted pyrazolopyrrolopyrimidine derivatives were synthesized, and their vasorelaxing and hypotensive activities were evaluated. The syntheses were efficiently accomplished through the use of three key intermediates (7, 16, and 24), as shown in Schemes I-III. The desired pharmacological activities were confirmed on the basis of vasorelaxing activity in rat aorta (in vitro) and hypotensive activity in rats (in vivo). Specifically, compound 25 exhibited the strongest activity and appears to be a promising clinical lead for the development of a new antihypertensive agent.

Both Fas ligand (FasL) and tumor necrosis factor-alpha (TNF-alpha) are type II integral membrane proteins. Recently, we have reported that FasL is processed to a soluble form by an unknown metalloproteinase at the cell surface and some hydroxamate matrix metalloproteinase (MMP) inhibitors inhibit the processing similar to the case observed with TNF-1alpha. We studied the inhibitory effects of various hydroxamate MMP inhibitors on FasL and TNF-alpha processing in order to characterize the processing enzymes using human FasL cDNA transfectants and LPS-stimulated THP-1 cells. It turned out that (1) the P1' group of hydroxamates was very important for the selective inhibitory activity toward TNF-alpha and FasL processing, (2) P1' 3-phenylpropyl group was favorable for the inhibition of FasL processing, and (3) P1' isobutyl and isopropyl groups were favorable for that of TNF-alpha processing. These differences in sensitivity to inhibitors imply that (1) membrane-bound FasL and TNF-alpha might be processed by distinct metalloproteinases, (2) the S1' site of FasL processing enzyme differs from that of MMP-1 and MMP-9, but appears to be similar to that of MMP-3, and (3) the S1' site of TNF-alpha processing enzyme is smaller than that of FasL processing enzyme. These results would be helpful in designing a more selective inhibitor.

In order to get an insight for designing novel inhibitors of aldose reductase, we analyzed relationships between structures of spiroquinazolinones and their inhibitory activities against rabbit aldose reductase by comparative molecular field analysis and molecular modeling of the enzyme-inhibitor complex. It was revealed that the following interactions were operative for the enhancement of inhibitory activity; 1) the hydrophobic interaction between substituents at the 6'- and 7'-position of quinazolinone and the hydrophobic residues such as Trp20, Val47, Tyr48, Tyr121 and Phe122; 2) the electrostatic interaction formed between electronegative substituents at the 6'-position and the side chain of Gln49; 3) the complementary fit of sterically small 6'-substituents to the active site.

We present a calculation for the binding free energy difference between two complexes of the class C beta-lactamase from Enterobacter cloacae with foramidocillin (FOPC) and with piperacillin (PIPC). The calculation was carried out by means of the thermodynamic integration (TI) method implemented with molecular dynamics (MD). By use of the available crystal structure of the class C beta-lactamase from E. cloacae, the structures of the beta-lactamase-FOPC (FOPC complex) and beta-lactamase-PIPC (PIPC complex) complexes were built by molecular modeling and equilibrated with MD simulations. FOPC were gradually converted into PIPC in both the solution and the enzyme system by means of MD/TI methods during the MD simulation. The structure of the PIPC complex as derived by the MD/TI simulation was similar to that of the PIPC complex obtained from molecular modeling. The calculated difference in the free energy of binding (deltadeltaGbind) was -2.2 kcal/mol. This compares well with the experimental value of -1.5 kcal/mol. The results indicate that the binding affinity of FOPC is lower than that of PIPC because of the greater difficulty of desolvation for FOPC upon binding to the enzyme. This calculation suggests that the desolvation of the ligand, as well as its interaction with the beta-lactamase, is important in understanding the relative affinity of the ligands with beta-lactamase.

Blockade of the action of angiotensin ii (AII) has long been a target for development of novel antihypertensive agents. We recently discovered a novel class of potent non-peptide AII receptor antagonists, benzimidazole-7-carboxylic acids including candesartan. Candesartan is a highly potent and insurmountable antagonist selective in the angiotensin II type-I receptor (AT1). Structure-activity relationship (SAR) studies revealed that the adjacent arrangement of a lipophilic substituent, a tetrazolylbiphenylmethyl moiety and a carboxyl group was the important structural requirement for potent AII antagonistic activity. Especially, the presence of a carboxyl group at the 7-position was found to be essential for insurmountable antagonism. To improve bioavailability of candesartan, chemical modification was examined to yield candesartan cilexetil, a prodrug of candesartan. Candesartan cilexetil is a potent and long-acting blocker that, when given once-daily to patients, provides effective 24 hr blood pressure control.