Biomedical subjects

Nicholas J Westwood

Publications and source records attributed to Nicholas J Westwood.

6 recordsLinked to original sources

PubMed2005

Pilot screening programme for small molecule activators of p53.

Activation of the p53 tumour suppressor is predicted to have therapeutically beneficial effects. Many current anti-cancer therapies activate the p53 response via DNA damage. Non-genotoxic activation of the p53 pathway would open the way to long-term and possibly prophylactic treatments. We have established a simple protocol to screen small compound libraries for activators of p53-dependent transcription, and to select and characterise the most interesting hits, which include non-genotoxic activators. These compounds or their derivatives are of potential clinical interest. This approach may also lead to the identification of novel p53-activating compound families and possibly to the description of novel molecular pathways regulating p53 activity.

Animals↗

PubMed2005

Controlling the outcome of an N-alkylation reaction by using N-oxide functional groups.

Covalent modifiers of proteins are of importance in chemical proteomics, an emerging chemical technology used to assign protein function. In this study, high-field (1)H NMR techniques were used to analyze the reaction of the bioactive compound, 2,3-bis(bromomethyl)quinoxaline 1,4-dioxide, with amines (a model system for proteins containing nitrogen-based nucleophiles). Unexpectedly, the results show that a double nucleophilic substitution reaction involving 2 equiv of the amine is preferred to an intramolecular cyclization pathway. A direct comparison with the reaction carried out on a substrate lacking the N-oxide functional groups is also provided. X-ray crystal structures and computational studies are used to rationalize the observed differences in reactivity between the two systems.

Alkylation↗

PubMed2004

Chemical genetics: how does it function?

This article highlights recent successes in the field of chemical genetics. It discusses the challenges inherent in this interdisciplinary research field and focuses on the essential role that the biologically aware synthetic chemist can play.

Animals↗

PubMed2004

A high-throughput cell migration assay using scratch wound healing, a comparison of image-based readout methods.

BACKGROUND: Cell migration is a complex phenomenon that requires the coordination of numerous cellular processes. Investigation of cell migration and its underlying biology is of interest to basic scientists and those in search of therapeutics. Current migration assays for screening small molecules, siRNAs, or other perturbations are difficult to perform in parallel at the scale required to screen large libraries. RESULTS: We have adapted the commonly used scratch wound healing assay of tissue-culture cell monolayers to a 384 well plate format. By mechanically scratching the cell substrate with a pin array, we are able to create characteristically sized wounds in all wells of a 384 well plate. Imaging of the healing wounds with an automated fluorescence microscope allows us to distinguish perturbations that affect cell migration, morphology, and division. Readout requires ~1 hr per plate but is high in information content i.e. high content. We compare readouts using different imaging technologies, automated microscopy, scanners and a fluorescence macroscope, and evaluate the trade-off between information content and data acquisition rate. CONCLUSIONS: The adaptation of a wound healing assay to a 384 well format facilitates the study of aspects of cell migration, tissue reorganization, cell division, and other processes that underlie wound healing. This assay allows greater than 10,000 perturbations to be screened per day with a quantitative, high-content readout, and can also be used to characterize small numbers of perturbations in detail.

Actins↗

PubMed2004

A small-molecule approach to studying invasive mechanisms of Toxoplasma gondii.

Toxoplasma gondii is the most common protozoan parasite of humans. Infection with T. gondii can lead to life-threatening disease as a result of repeated cycles of host cell invasion, parasite replication, and host cell lysis. Relatively little is known about the invasive mechanisms of T. gondii and related parasites within the Phylum Apicomplexa (including Plasmodium spp., the causative agents of malaria), due to difficulties associated with studying genes essential to invasion in haploid obligate intracellular organisms. To circumvent this problem, we have developed a high-throughput microscope-based assay, which we have used to screen a collection of 12,160 structurally diverse small molecules for inhibitors of T. gondii invasion. A total of 24 noncytotoxic invasion inhibitors were identified. Secondary assays demonstrated that different inhibitors perturb different aspects of invasion, including gliding motility, secretion of host cell adhesins from apical organelles (the micronemes), and extension of a unique tubulin-based structure at the anterior of the parasite (the conoid). Unexpectedly, the screen also identified six small molecules that dramatically enhance invasion, gliding motility, and microneme secretion. The small molecules identified here reveal a previously unrecognized complexity in the control of parasite motility and microneme secretion, and they constitute a set of useful probes for dissecting the invasive mechanisms of T. gondii and related parasites. Small-molecule-based approaches provide a powerful means to address experimentally challenging problems in host-pathogen interaction, while simultaneously identifying new potential targets for drug development.

Animals↗

PubMed2002

Using small molecules to study big questions in cellular microbiology.

High-throughput screening of small molecules is used extensively in pharmaceutical settings for the purpose of drug discovery. In the case of antimicrobials, this involves the identification of small molecules that are significantly more toxic to the microbe than to the host. Only a small percentage of the small molecules identified in these screens have been studied in sufficient detail to explain the molecular basis of their antimicrobial effect. Rarer still are small molecule screens undertaken with the explicit goal of learning more about the biology of a particular microbe or the mechanism of its interaction with its host. Recent technological advances in small molecule synthesis and high-throughput screening have made such mechanism-directed small molecule approaches a powerful and accessible experimental option. In this article, we provide an overview of the methods and technical requirements and we discuss the potential of small molecule approaches to address important and often otherwise experimentally intractable problems in cellular microbiology.

Animals↗