Synthesis and SAR of indazole-pyridine based protein kinase B/Akt inhibitors

A series of heteroaryl-pyridine containing inhibitors of Akt are reported. The synthesis and structure-activity relationships are discussed, leading to the discovery of a indazole-pyridine analogue (K(i)=0.16 nM). These compounds bind in the ATP binding site, are potent, ATP competitive, and reversible inhibitors of Akt activity. No selectivity amongst the Akt isoforms is observed for this analogue, but there is good selectivity against an panel of other kinases. It is least selective for other members of the AGC family of kinases but is nonetheless 40-fold selective for Akt over PKA. The compound shows cellular activity and significantly slows tumor growth in vivo.     

Myocardial remodeling after discrete radiofrequency injury: effects of tissue inhibitor of matrix metalloproteinase-1 gene deletion

Discrete myocardial lesions created through the delivery of radiofrequency (RF) energy can expand; however, the mechanisms have not been established. Matrix metalloproteinases (MMPs) play an important role in myocardial remodeling, and MMP activity can be regulated by the tissue inhibitors of the metalloproteinases (TIMPs). This study examined the role of TIMP-1 in postinjury myocardial remodeling. Lesions were created on the left ventricular (LV) epicardium of wild-type (WT, 8-12 wk, 129SVE) and age-matched TIMP-1 gene-deficient (timp-1(-/-)) mice through the delivery of RF current (80 degrees C, 30 s). Heart mass, LV scar volumes, and collagen content were measured at 1 h and 3, 7, and 28 days postinjury (n = 10 each). Age-matched, nonablated mice were used as reference controls (n = 5). Heart mass indexed to tibial length increased in WT and timp-1(-/-) mice but was greater in the timp-1(-/-) mice by 7 days. Scar volumes increased in a time-dependent manner in both groups but were higher in the timp-1(-/-) mice than the WT mice at 7 days (1.48 +/- 0.09 vs. 1.20 +/- 0.11 mm(3).mg(-1).mm, P < 0.05) and remained higher at 28 days. In the remote myocardium, wall thickness was greater and relative collagen content was lower in the timp-1(-/-) mice at 28 days postinjury. Discrete myocardial RF lesions expand in a time-dependent manner associated with myocyte hypertrophy remote to the scar. Moreover, postinjury myocardial remodeling was more extensive with TIMP-1 gene deletion. Thus TIMP-1 either directly or through modulation of MMP activity may regulate myocardial remodeling following infliction of a discrete injury.     

Synthesis and activity of 1-aryl-1'-imidazolyl methyl ethers as non-thiol farnesyltransferase inhibitors

A series of imidazole-containing methyl ethers (4-5) have been designed and synthesized as potent and selective farnesyltransferase inhibitors (FTIs) by transposition of the D-ring to the methyl group on the imidazole of the previously reported FTIs 3. Several compounds such as 4h and 5b demonstrate superior enzymatic activity to the current benchmark compound tipifarnib (1) with IC(50) values in the lower subnanomolar range, while maintaining excellent cellular activity comparable to tipifarnib. The compounds are characterized as being simple, easier to make, and possess no chiral center involved.     

Site-specific genomic (SSG) and random domain-localized (RDL) mutagenesis in yeast

Background  

A valuable weapon in the arsenal available to yeast geneticists is the ability to introduce specific mutations into yeast genome. In particular, methods have been developed to introduce deletions into the yeast genome using PCR fragments. These methods are highly efficient because they do not require cloning in plasmids.     

Aryl tetrahydropyridine inhibitors of farnesyltransferase: bioavailable analogues with improved cellular potency

Inhibitors of farnesyltransferase are effective against a variety of tumors in mouse models of cancer. Clinical trials to evaluate these agents in humans are ongoing. In our effort to develop new farnesyltransferase inhibitors, we have discovered bioavailable aryl tetrahydropyridines that are potent in cell culture. The design, synthesis, SAR and biological properties of these compounds will be discussed.     

Isolation and Characterisation of Chemotactic Mutants of Chlamydomonas reinhardtii obtained by Insertional Mutagenesis

The swimming behaviour of the green flagellated protist Chlamydomonas reinhardtii is influenced by several different external stimuli including light and chemical attractants. Common components are involved in both the photo- and chemo-sensory transduction pathways, although the nature and organisation of these pathways are poorly understood. To learn more about the mechanism of chemotaxis in Chlamydomonas, we have generated nonchemotactic strains by insertional mutagenesis. The arginine-requiring strain arg7-8 was transformed with DNA carrying the wild-type ARG7 gene. Of the 8630 arginine-independent transformants obtained, five are defective in their chemotaxis towards various sugars. Two of the mutants (CTX2 and CTX3) are blocked only in their response to xylose. Mutant CTX1 is blocked in its response to xylose, maltose and mannitol, but displays normal taxis to sucrose. Mutants CTX4 and CTX5 lack chemotactic responses to all sugars tested. CTX1, CTX4 and CTX5 represent novel chemotactic phenotypes not previously obtained using ultra-violet or chemical mutagenesis. Genetic analysis confirms that each mutation maps to a single nuclear locus that is unlinked to the mating-type locus. Further analysis of CTX4 indicates that the mutant allele is tagged by the transforming ARG7 DNA. CTX4 appears to be defective in a component specific for chemotactic signal transduction since it exhibits wild-type photobehavioural responses (phototaxis and photoshock) as well as the wild-type responses of EGTA-induced trans-flagellum inactivation and acid-induced deflagellation. Insertional mutagenesis has thus permitted the generation of novel chemotactic mutants that will be of value in the molecular dissection of the signalling machinery.