ER+, ErbB-1+, and/or ErbB-2+ primary breast cancer responded well to letrozole, but responses to tamoxifen were infrequent. This suggests that ErbB-1 and ErbB-2 signaling through ER is ligand-dependent and that the growth-promoting effects of these receptor tyrosine kinases on ER+ breast cancer can be inhibited by potent estrogen deprivation therapy.

In mammals, specific lipids and amino acids serve as crucial signaling molecules. In bacteria, conjugates of lipids and amino acids (referred to as lipoamino acids) have been identified and found to possess biological activity. Here, we report that mammals also produce lipoamino acids, specifically the arachidonyl amino acids. We show that the conjugate of arachidonic acid and glycine (N-arachidonylglycine (NAGly)) is present in bovine and rat brain as well as other tissues and that it suppresses tonic inflammatory pain. The biosynthesis of NAGly and its degradation by the enzyme fatty acid amide hydrolase can be observed in rat brain tissue. In addition to NAGly, bovine brain produces at least two other arachidonyl amino acids: N-arachidonyl ␥-aminobutyric acid (NAGABA) and N-arachidonylalanine. Like NAGly, NAGABA inhibits pain. These findings open the door to the identification of other members of this new class of biomolecules, which may be integral to pain regulation and a variety of functions in mammals.Molecules found in bacteria that consist of a lipid moiety conjugated to an amino acid have been termed lipoamino acids (1-3). Burstein et al. (4) found that the lipoamino acid Narachidonylglycine (NAGly) 1 causes hot plate analgesia in mice, indicating its possible biological relevance in mammals. NAGly was first synthesized (5) as a structural analog of the endogenous cannabinoid anandamide (6), and it was found to lack affinity for the cannabinoid CB1 receptor. We hypothesized that NAGly may be produced by mammalian tissues because it is composed of the naturally occurring compounds glycine and arachidonic acid. Herein we show that at least three arachidonyl amino acids are natural constituents in mammalian brain: NAGly, N-arachidonyl ␥-aminobutyric acid (NAGABA), and N-arachidonylalanine (NAAla). One member of this group, NAGly, is characterized in detail here. It is synthesized in situ in rat brain tissue from the precursors arachidonic acid and glycine, and it is hydrolyzed by the enzyme fatty acid amide hydrolase (FAAH). NAGly is widely distributed among mammalian tissues, implying multiple functions. One possible physiological function of NAGly is pain suppression, indicated by its marked suppression of formalininduced pain behavior in rats, confirming a previous report of analgesic activity in mice (4). EXPERIMENTAL PROCEDURESTissue Extraction and Purification-The procedure comprised a liquidliquid extraction modified from that described by Folch et al. (7) followed by a series of solid-phase separations. Fresh bovine brain and rat organs were homogenized in the methanol fraction of 20 volumes of 2:1 chloroform:methanol and centrifuged for 15 min at 31,000 ϫ g at 4°C. Chloroform was then added to the supernatant. NaCl (0.2 volume, 0.73%) was mixed with the crude homogenate, and the solution was allowed to separate overnight at 4°C or centrifuged at 1,000 ϫ g for 15 min. The upper phase was discarded and the interphase washed twice. The lower phase was then applied to diethylaminopropyl silica-based...

Summary The BCL6 transcriptional repressor is the most frequently involved oncogene in diffuse large B cell lymphoma (DLBCL). We combined computer-aided drug design with functional assays to identify low molecular weight compounds that bind to the corepressor binding groove of the BCL6 BTB domain. One such compound disrupted BCL6/corepressor complexes in vitro and in vivo, and was observed by X-ray crystallography and NMR to bind the critical site within the BTB groove. This compound could induce expression of BCL6 target genes and kill BCL6-positive DLBCL cell lines. In xenotransplantation experiments, the compound was non-toxic and potently suppressed DLBCL tumors in vivo. The compound also killed primary DLBCLs from human patients.

In the absence of three-dimensional (3D) structures of potential drug targets, ligand-based drug design is one of the popular approaches for drug discovery and lead optimization. 3D structureactivity relationships (3D QSAR) and pharmacophore modeling are the most important and widely used tools in ligand-based drug design that can provide crucial insights into the nature of the interactions between drug target and ligand molecule and provide predictive models suitable for lead compound optimization. This review article will briefly discuss the features and potential application of recent advances in ligand-based drug design, with emphasis on a detailed description of a novel 3D QSAR method based on the conformationally sample pharmacophore (CSP) approach (denoted CSP-SAR). In addition, data from a published study is used to compare the CSP-SAR approach to the Catalyst method, emphasizing the utility of the CSP approach for ligand-based model development.

Both of the enantiomers of 5-(3-hydroxyphenyl)-N-phenylethylmorphan with C9alpha-methyl, C9-methylene, C9-keto, and C9alpha- and C9beta-hydroxy substituents were synthesized and pharmacologically evaluated. Three of the 10 compounds, (1R,5R,9S)-(-)-9-hydroxy-5-(3-hydroxyphenyl-2-phenylethyl-2-azabicyclo[3.3.1]nonane ((1R,5R,9S)-(-)-10), (1R,5S)-(+)-5-(3-hydroxyphenyl)-9-methylene-2-phenethyl-2-azabicyclo[3.3.1]nonane ((1R,5S)-(+)-14), and (1R,5S,9R)-(-)-5-(3-hydroxyphenyl)-9-methyl-2-phenethyl-2-azabicyclo[3.3.1]nonane ((1R,5S,9R)-(+)-15) had subnanomolar affinity at mu-opioid receptors (Ki = 0.19, 0.19, and 0.63 nM, respectively). The (1R,5S)-(+)-14 was found to be a mu-opioid agonist and a mu-, delta-, and kappa-antagonist in [35S]GTP-gamma-S assays and was approximately 50 times more potent than morphine in a number of acute and subchronic pain assays, including thermal and visceral models of nociception. The (1R,5R,9S)-(-)-10 compound with a C9-hydroxy substituent axially oriented to the piperidine ring (C9beta-hydroxy) was a mu-agonist about 500 times more potent than morphine. In the single-dose suppression assay, it was greater than 1000 times more potent than morphine. It is the most potent known phenylmorphan antinociceptive. The molecular structures of these compounds were energy minimized with density functional theory at the B3LYP/6-31G* level and then overlaid onto (1R,5R,9S)-(-)-10 using the heavy atoms in the morphan moiety as a common docking point. Based on modeling, the spatial arrangement of the protonated nitrogen atom and the 9beta-OH substituent in (1R,5R,9S)-(-)-10 may facilitate the alignment of a putative water chain enabling proton transfer to a nearby proton acceptor group in the mu-opioid receptor.

Previous studies suggest that P-glycoprotein (P-gp) modulates the PK/PD of many compounds including opioid agonists and chemotherapeutic agents. The objective of this study was to assess the P-gp affinity status of oxycodone, the P-gp expression, and the paclitaxel's tissue distribution in oxycodone-treated rats. P-gp ATPase assay, Caco-2 transepithelial permeability studies, and mdr1a/b (−/−) mice were used to assess the P-gp affinity status of oxycodone. P-gp expression was determined by Western blot analysis while [ 14 C] paclitaxel's distributions in the liver, kidney, brain, and plasma tissues were determined by liquid scintillation counter. Oxycodone stimulated the P-gp ATPase activity in a concentration-dependant manner. The Caco-2 secretory transport of oxycodone was reduced from 3.64 ×10 −5 to 1.96 × 10 −5 cm/s (p <0.05) upon preincubation with the P-gp inhibitor, verapamil. The brain levels of oxycodone in mdr1a/b (+/+) were not detectable (<15 ng/mL) while in mdr1a/b (−/−) the average levels were 115 ± 39 ng/mL. The P-gp protein levels were increased by 1.3-4.0 folds while paclitaxel's tissue distributions were decreased by 38-90% (p <0.05) in oxycodone-treated rats. These findings display that oxycodone is a P-gp substrate, induces overexpression of P-gp, and affects paclitaxel's tissue distribution in a manner that may influence its chemotherapeutic activity.

Methamphetamine (METH) and many other abused substances interact with σ receptors. σ Receptors are found on dopaminergic neurons and can modulate dopaminergic neurotransmission. Antisense knock down of σ receptors also mitigates METH-induced stimulant effects, suggesting that these proteins are viable medication development targets for treating pscyhostimulant abuse. In the present study, AC927, a σ receptor antagonist, was evaluated for its ability to attenuate METH-induced effects in vivo and in vitro. Radioligand binding studies showed that AC927 had preferential affinity for σ receptors compared to 29 other receptors, transporters and ion channels. Pretreatment of male, Swiss Webster mice with AC927 significantly attenuated METH-induced locomotor stimulation, striatal dopamine depletions, striatal dopamine transporter reductions, and hyperthermia. When the neurotoxicity of METH was further examined in vitro under temperature-controlled conditions, coincubation with AC927 mitigated METH-induced cytotoxicity. Together, the results demonstrate that AC927 protects against METH-induced effects, and suggests a new strategy for treating psychostimulant abuse.

As part of an effort to inhibit S100B, structures of pentamidine (Pnt) bound to Ca 2+ -loaded and Zn 2+ ,Ca 2+ -loaded S100B were determined by X-ray crystallography at 2.15 Å (R free = 0.266) and 1.85 Å (R free = 0.243) resolution, respectively. These data were compared to X-ray structures solved in the absence of Pnt, including Ca 2+ -loaded S100B and Zn 2+ ,Ca 2+ -loaded S100B determined here (1.88 Å; R free = 0.267). In the presence and absence of Zn 2+ , electron density corresponding to two Pnt molecules per S100B subunit was mapped for both drug-bound structures. One Pnt binding site (site 1) was adjacent to a p53 peptide binding site on S100B (±Zn 2+ ), and the second Pnt molecule was mapped to the dimer interface (site 2; ±Zn 2+ ) and in a pocket near residues that define the Zn 2+ binding site on S100B. In addition, a conformational change in S100B was observed upon the addition of Zn 2+ to Ca 2+ -S100B, which changed the conformation and orientation of Pnt bound to sites 1 and 2 of Pnt-Zn 2+ ,Ca 2+ -S100B when compared to Pnt-Ca 2+ -S100B. That Pnt can adapt to this Zn 2+ -dependent conformational change was unexpected and provides a new mode for S100B inhibition by this drug. These data will be useful for developing novel inhibitors of both Ca 2+ -and Ca 2+ ,Zn 2+ -bound S100B.