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Targeting mutant KRAS for anticancer therapeutics: a review of novel small molecule modulators. - Journal of medicinal chemistry
The RAS proteins play a role in cell differentiation, proliferation, and survival. Aberrant RAS signaling has been found to play a role in 30% of all cancers. KRAS, a key member of the RAS protein family, is an attractive cancer target, as frequent point mutations in the KRAS gene render the protein constitutively active. A number of attempts have been made to target aberrant KRAS signaling by identifying small molecule compounds that (1) are synthetic lethal to mutant KRAS, (2) block KRAS/GEF interactions, (3) inhibit downstream KRAS effectors, or (4) inhibit the post-translational processing of RAS proteins. In addition, inhibition of novel targets outside the main KRAS signaling pathway, specifically the cell cycle related kinase PLK1, has been shown have an effect in cells that harbor mutant KRAS. Herein we review the use of various high-throughput screening assays utilized to identify new small-molecule compounds capable of targeting mutant KRAS-driven cancers.
Synthesis of Tetrazolo-Fused Benzodiazepines and Benzodiazepinones by a Two-Step Protocol Using an Ugi-Azide Reaction for Initial Diversity Generation. - Tetrahedron
A two-step strategy for the synthesis of arrays of tricyclic tetrazolo-fused benzodiazepines and benzodiazepinones has been investigated. The protocol uses ortho-N-Boc phenylisocyanides and phenylglyoxaldehydes or ethyl glyoxylate in the 4-component Ugi-Azide reaction to afford MCR (Multi Component Reactions) derived adducts equipped with the desired diversity inputs. A subsequent acidic treatment (TFA/DCE) allows a simultaneous deprotection-cyclization leading to the final products.
Gaining insights into the small molecule targeting of the G-quadruplex in the c-MYC promoter using NMR and an allele-specific transcriptional assay. - Topics in current chemistry
G-quadruplexes (four-stranded DNA secondary structures) are showing promise as new targets for anticancer therapies. Specifically, G-quadruplexes in the proximal promoter region of regulatory genes have the potential to act as silencer elements and thereby turn off transcription. Thus, compounds that are capable of binding to and stabilizing G-quadruplexes would be of great benefit. In this chapter we describe two recent studies from our labs. In the first case, we use NMR to elucidate the structure of a 2:1 complex between a small molecule and the G-quadruplex in the c-MYC promoter. In the second case, we use an allele-specific transcription assay to demonstrate that the effect of a G-quadruplex-interactive compound is mediated directly through the G-quadruplex. Finally, we use this information to propose models for the interaction of various small molecules with the c-MYC G-quadruplex.
Softening the Rule of Five--where to draw the line? - Bioorganic & medicinal chemistry
In order to improve the discovery and development of new drugs, a broad effort is being made to assess the 'drug-like' properties of molecules in early stages of the discovery-research process. Although there are numerous approaches to this problem, perhaps the simplest and most widespread one is that developed by Chris Lipinski and his co-workers at Pfizer, which is generally referred either as the Lipinski Rules or the Rule of Five (ROF). The ROF is based on four properties of molecules, namely, molecular weight (MW), log P, number of hydrogen bond donors (HBD), and the number of hydrogen bond acceptors (HBA). A 'flag' is set if the value of a given property exceeds the chosen threshold value for that property-MW 500 Da, log P 5, the number of HBDs 5, and the number of HBAs 10. Each flag corresponds to an ROF violation. The total number of violations is the ROF-Score, which lies between '0' and '4'. Molecules with ROF-Scores greater than one are considered to be marginal for further development. The difficulty with this approach is that two molecules with nearly identical property values can, nonetheless, possess ROF-Scores that can differ by two or more. Thus, one molecule could be considered for further studies while the other, nearly identical molecule (in terms of its four ROF properties), would most likely not be. This problem arises because of the sharp thresholds imposed by the present formulation of the ROF, which is based upon classical sets. In the current work an alternative approach based on the use of utility functions, within the framework of the analytic hierarchy process (AHP), are employed to 'soften' the sharp boundaries inherent in classical sets. This provides a more realistic assessment of compounds in terms of their potential suitability in drug-discovery research programs.Copyright Â© 2011 Elsevier Ltd. All rights reserved.
Concise Two-Step Solution Phase Syntheses of four novel Dihydroquinazoline scaffolds. - Tetrahedron letters
Novel two-step solution phase protocols for the synthesis of dihydroquinazolines and fused dihydroquinazoline-benzodiazepine tetracycles are reported. The methodology employs the Ugi reaction to assemble desired diversity and acid treatment enables ring closing transformations. The protocols are further facilitated by the use of microwave irradiation and n-butyl isocyanide to control the rate of each ring forming transformation.
Chemogenomic analysis identifies Macbecin II as a compound specific for SMAD4-negative colon cancer cells. - Chemical biology & drug design
The tumor suppressor gene, SMAD4, is mutated in approximately 30% of colon cancers. To identify compounds with enhanced potency on cells with a SMAD4-negative context, we combined genomic and cheminformatic analyses of publicly available data relating to the colon cancer cell lines within the NCI60 panel. Two groups of cell lines were identified with either wild-type or negative SMAD4 status. A cheminformatic analysis of the NCI60 screening data was carried out, which led to the identification of 14 compounds that preferentially inhibited cell growth of the SMAD4-negative cell lines. Using cell viability assays, the effect of these compounds was validated on four colon cancer cell lines: HCT-116 and HCT-15 (SMAD4-expressing), and HT-29 and COLO-205 (SMAD4-negative). Our data identified Macbecin II, a hydroquinone ansamycin antibiotic, as having increased potency in the SMAD4-negative cells compared to SMAD4 wild-type cells. In addition, we showed that silencing of SMAD4 using siRNA in HCT-116 enhanced Macbecin II potency. Our results demonstrate that Macbecin II is specifically active in colon cancer cells having a SMAD4-negative background and thus is a potential candidate for further investigation in a drug discovery perspective.
4-(Piperidin-1-yl)-4H-benzo[b]tetra-zolo[1,5-d][1,4]diazepin-5(6H)-one. - Acta crystallographica. Section E, Structure reports online
There are two crystallographically unique mol-ecules present in the asymmetric unit of the title compound, C(14)H(16)N(6)O; in both mol-ecules, the seven-membered diazepinone ring adopts a boat-like conformation and the chair conformation piperidine ring is an axial substituent on the diazepinone ring. In the crystal, each mol-ecule forms hydrogen bonds with its respective symmetry equivalents. Hydrogen bonding between mol-ecule A and symmetry equivalents forms two ring motifs, the first formed by inversion-related N-Hâ‹¯O inter-actions and the second formed by C-Hâ‹¯O and C-Hâ‹¯N inter-actions. The combination of both ring motifs results in the formation of an infinite double tape, which propagates in the a-axis direction. Hydrogen bonding between mol-ecule B and symmetry equivalents forms one ring motif by inversion-related N-Hâ‹¯O inter-actions and a second ring motif by C-Hâ‹¯O inter-actions, which propagate as a single tape parallel with the c axis.
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1660 S Columbian Way Seattle, WA 98108
1660 S Columbian Way (S-112-Pod) Vapshcs Seattle Division #0114
1660 S Columbian Way Diagnostic Imaging, S-Rad-114
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1660 S Columbian Way, Room 6A-102 Veterans Health Administration Puget Sound