We have previously shown that appropriate modification of the benzocycloheptapyridine tricyclic ring system can provide potent farnesyl protein transferase (FPT) inhibitors with good cellular activity. Our laboratories have also established that incorporation of either pyridinylacetyl N-oxide or 4-N-carboxamidopiperidinylacetyl moieties results in pharmacokinetically stable inhibitors that are orally efficacious in nude mice. We now demonstrate that further elaboration of the tricyclic ring system by introducing a bromine atom at the 7- or the 10-position of the 3-bromo-8-chlorotricyclic ring system provides compounds that have superior potency and selectivity in FPT inhibition. These compounds have good serum levels and half-lives when given orally to rodents and primates. In vitro and in vivo evaluation of a panel of these inhibitors has led to identification of 15 (SCH 66336) as a highly potent (IC50 = 1.9 nM) antitumor agent that is currently undergoing human clinical trials.
Emerging initiatives in British Columbia and elsewhere clearly suggest that by working with tourism stakeholders, the wine industry can not only contribute to the development of rural tourism, but it can also gain valuable direct marketing and value added sales advantages. For these benefits to be fully realized, more must be known about the character of travel markets interested in wine tourism. To provide insights into BC's domestic wine tourist markets, this research involves two overriding phases of investigation. Initially, it conducts an overview analysis of BC's domestic wine tourists. The second phase of the study involves describing a small but valuable and growing niche market of culturally oriented wine tourists. It then suggests several product development strategies suited to attracting and retaining such wine tourists. The strategies relate to incorporating a range of wine and non‐wine related activities into the tourism experience, creating strong connections between local wines and regional cuisine, building cultural and heritage dimensions into wine tourism product packages, incorporating and promoting environmentally friendly resource management practices; and, protecting wine tourism landscapes. While the empirical part of this investigation is focused on BC wine tourists, the findings provide insights into strategies suited to other wine producing regions in Canada and elsewhere.
HIV persistence in
latently infected, resting CD4+ T
cells is broadly considered a barrier to eradicate HIV. Activation
of the provirus using latency-reversing agents (LRAs) followed by
immune-mediated clearance to purge reservoirs has been touted as a
promising therapeutic approach. Histone deacetylases (HDACs) and histone
acetyltransferases (HATs) control the acetylation level of lysine
residues in histones to regulate the gene transcription. Several clinical
HDAC inhibitors had been examined as LRAs, which induced HIV activation
in vitro and in vivo. Here we report the discovery of a series of
selective and potent class I HDAC inhibitors based on aryl ketones
as a zinc binding group, which reversed HIV latency using a Jurkat
model of HIV latency in 2C4 cells. The SAR led to the discovery of
a highly selective class I HDAC inhibitor 10 with excellent
potency. HDACi 10 induces the HIV gag P24 protein in patient latent CD4+ T cells.
The selectivity of histone deacetylase inhibitors (HDACis) is greatly impacted by the zinc binding groups. In an effort to search for novel zinc binding groups, we applied a parallel medicinal chemistry (PMC) strategy to quickly synthesize substituted benzamide libraries. We discovered a series containing 2-substituted benzamides as the zinc binding group which afforded highly selective and potent HDAC3 inhibitors, exemplified by compound 16 with a 2-methylthiobenzamide. Compound 16 inhibited HDAC3 with an IC 50 of 30 nM and with unprecedented selectivity of >300-fold over all other HDAC isoforms. Interestingly, a subtle change of the 2-methylthio to a 2-hydroxy benzamide in 20 retains HDAC3 potency but loses all selectivity over HDAC 1 and 2. This significant difference in selectivity was rationalized by X-ray crystal structures of HDACis 16 and 20 bound to HDAC2, revealing different binding modes to the catalytic zinc ion. This series of HDAC3 selective inhibitors served as tool compounds for investigating the minimal set of HDAC isoforms that must be inhibited for the HIV latency activation in a Jurkat 2C4 cell model and potentially as leads for selective HDAC3 inhibitors for other indications.
The emergence and evolution of new immunological cancer therapies has sparked a rapidly growing interest in discovering novel pathways to treat cancer. Toward this aim, a novel series of pyrrolidine derivatives (compound ) were identified as potent inhibitors of ERK1/2 with excellent kinase selectivity and dual mechanism of action but suffered from poor pharmacokinetics (PK). The challenge of PK was overcome by the discovery of a novel 3()-thiomethyl pyrrolidine analog . Lead optimization through focused structure-activity relationship led to the discovery of a clinical candidate suitable for twice daily oral dosing as a potential new cancer therapeutic.
A series of aldose reductase inhibitors were prepared which were analogues of the potent, orally active inhibitor tolrestat (1). These compounds (5, 7, 9, and 10) have an extra substituent on one of the unoccupied positions on the naphthalene ring of 1. Primary amide prodrugs of several members from the series 5 and 7, namely 6 and 8, respectively, were also prepared. These compounds were evaluated in two in vitro systems: an isolated enzyme preparation from bovine lens to assess their intrinsic inhibitory activity and an isolated sciatic nerve assay to determine their ability to penetrate membranes of nerve tissue. These compounds were also evaluated in vivo as inhibitors of galactitol accumulation in the lens, sciatic nerve, and diaphragm of galactose-fed rats. In general, compounds in series 5, 7, 9, and 10 were potent inhibitors of bovine lens aldose reductase. 2-Halo-substituted analogues from the series 5, 7, and 9 exhibited high activity in the nerve of the 4-day-galactose-fed rat, and in several instances, the primary amide prodrug 8 enhanced the in vivo potency of the respective carboxylic acid 7. Two 2-fluoro-derivatives, 8a and 9a, had especially high activity in vivo and were chosen for additional studies. These compounds were found to be approximately equipotent to tolrestat in the sciatic nerve of the galactose-fed rat and the STZ rat, as judged by their ED50's in these assays. Although primary amide analogue 8a did not have intrinsic inhibitory activity toward aldose reductase, it was metabolized to an active form in vivo and also in vitro within the sciatic nerve.
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