Pharmacogenomics in the UK National Health Service: opportunities and challenges.

Despite increasing interest in pharmacogenomics, and the potential benefits to improve patient care, implementation into clinical practice has not been widespread. Recently, there has been a drive to implement genomic medicine into the UK National Health Service (NHS), largely spurred on by the success of the 100,000 Genomes Project. The UK Pharmacogenetics and Stratified Medicine Network, NHS England and Genomics England invited experts from academia, the healthcare sector, industry and patient representatives to come together to discuss the opportunities and challenges of implementing pharmacogenomics into the NHS. This report highlights the discussions of the workshop to provide an overview of the issues that need to be considered to enable pharmacogenomic medicine to become mainstream within the NHS.

Drug repurposing: progress, challenges and recommendations.

Given the high attrition rates, substantial costs and slow pace of new drug discovery and development, repurposing of 'old' drugs to treat both common and rare diseases is increasingly becoming an attractive proposition because it involves the use of de-risked compounds, with potentially lower overall development costs and shorter development timelines. Various data-driven and experimental approaches have been suggested for the identification of repurposable drug candidates; however, there are also major technological and regulatory challenges that need to be addressed. In this Review, we present approaches used for drug repurposing (also known as drug repositioning), discuss the challenges faced by the repurposing community and recommend innovative ways by which these challenges could be addressed to help realize the full potential of drug repurposing.

Defining drug response for stratified medicine.

The premise for stratified medicine is that drug efficacy, drug safety, or both, vary between groups of patients, and biomarkers can be used to facilitate more targeted prescribing, with the aim of improving the benefit:risk ratio of treatment. However, many factors can contribute to the variability in response to drug treatment. Inadequate characterisation of the nature and degree of variability can lead to the identification of biomarkers that have limited utility in clinical settings. Here, we discuss the complexities associated with the investigation of variability in drug efficacy and drug safety, and how consideration of these issues a priori, together with standardisation of phenotypes, can increase both the efficiency of stratification procedures and identification of biomarkers with the potential for clinical impact.

UK Pharmacogenetics and Stratified Medicine Network.

The UK Pharmacogenetics and Stratified Medicine Network is a not-for-profit organisation dedicated to bringing together groups of academics, clinicians, industry partners, and regulators with patient representatives to support the implementation pathway of stratified/precision/personalized/P4 medicine into the clinic to deliver improvements in drug delivery. Our collaborators database provides unique opportunities for members to engage with colleagues across all sectors of the stratified medicine landscape to promote their activities. Open meetings highlight research findings and the developments in stratified medicine. Focused workshops invite key experts to debate topics of interest and address the challenges of the whole pathway which will eventually lead to the wider adoption of stratified medicine. The website provides comprehensive information including latest news events, funding and education opportunities.

IgLONs form heterodimeric complexes on forebrain neurons.

IgLONs are a family of four GPI-anchored cell adhesion molecules that regulate neurite outgrowth and synaptogenesis and may act as tumour suppressor genes. Recently we have proposed that two members of the IgLON family act as a heterodimeric complex termed DIgLON. Neurons isolated from chick forebrain co-express all six combinations of IgLONs and the intensity of fluorescence for each pair of IgLONs was highly correlated. Antibody-patching experiments on forebrain neurons show complex formation for IgLON pairs but not between unrelated GPI-anchored glycoproteins. Thus IgLONs are the first GPI-anchored family of glycoproteins shown to form heterodimeric complexes in the plane of the membrane.

DIgLONs inhibit initiation of neurite outgrowth from forebrain neurons via an IgLON-containing receptor complex.

IgLONs are a family of four GPI-anchored cell adhesion molecules that regulate neurite outgrowth, synaptogenesis and may act as tumour suppressor genes. IgLONs are thought to function as monomers or homodimers and we have proposed that IgLONs also act as heterodimeric complexes termed Dimeric IgLONs or DIgLONs. Here we show that the initiation of neurite outgrowth is inhibited from a subset of chick embryonic day (E) 7 or 8 forebrain neurons when they are cultured on CHO cell lines expressing DIgLON:CEPU-1-OBCAM and DIgLON:CEPU-1-LAMP but not on CHO cells that express single IgLONs CEPU-1 or OBCAM. Surprisingly at the younger age of E6 forebrain neurons do not respond to DIgLONs. Since there is little difference in expression of IgLONs on the surface of chick forebrain neurons at these two ages we suggest IgLONs alone are not the receptor on the responding forebrain neurons. A DIgLON heterodimeric recombinant protein DIgLON:CEPU-1-OBCAM-Fc also blocked neurite outgrowth from E8 chick forebrain neurons. However, when IgLONs were removed from the surface of these E8 neurons they no longer responded to DIgLON:CEPU-1-OBCAM-Fc substrate, indicating that IgLONs form at least a component of the neuronal cell receptor complex involved in this inhibition of neurite outgrowth. Inhibitors pertussis toxin and Y27632 reversed the inhibition of neurite outgrowth on a DIgLON:CEPU-1-OBCAM and DIgLON:CEPU-1-LAMP substrate. This suggests the involvement of a G-protein coupled receptor and activation of Rho A. In summary we provide evidence that DIgLON:CEPU-1-OBCAM and DIgLON:CEPU-1-LAMP complexes regulate initiation of neurite outgrowth on forebrain neurons via an IgLON-containing receptor complex.

Cell shape-dependent Control of Ca2+ influx and cell cycle progression in Swiss 3T3 fibroblasts.

The ability of adherent cells such as fibroblasts to enter the cell cycle and progress to S phase is strictly dependent on the extent to which individual cells can attach to and spread on a substratum. Here we have used microengineered adhesive islands of 22 and 45 mum diameter surrounded by a nonadhesive substratum of polyhydroxyl methacrylate to accurately control the extent to which individual Swiss 3T3 fibroblasts may spread. The effect of cell shape on mitogen-evoked Ca2+ signaling events that accompany entry into the cell cycle was investigated. In unrestricted cells, the mitogens bombesin and fetal calf serum evoked a typical biphasic change in the cytoplasmic free Ca2+ concentration. However, when the spreading of individual cells was restricted, such that progression to S phase was substantially reduced, both bombesin and fetal calf serum caused a rapid transient rise in the cytoplasmic free Ca2+ concentration but failed to elicit the normal sustained influx of Ca2+ that follows Ca2+ release. As expected, restricting cell spreading led to the loss of actin stress fibers and the formation of a ring of cortical actin. Restricting cell shape did not appear to influence mitogen-receptor interactions, nor did it influence the presence of focal adhesions. Because Ca2+ signaling is an essential component of mitogen responses, these findings implicate Ca2+ influx as a necessary component of cell shape-dependent control of the cell cycle.

Diglons are heterodimeric proteins composed of IgLON subunits, and Diglon-CO inhibits neurite outgrowth from cerebellar granule cells.

IgLONs are a family of four cell adhesion molecules belonging to the Ig superfamily that are thought to play a role in cell-cell recognition and growth-cone migration. One member of the family, opioid-binding cell-adhesion molecule (OBCAM), might act as a tumour suppressor. Previous work has shown that limbic-system-associated protein (LAMP), CEPU-1/Neurotrimin and OBCAM interact homophilically and heterophilically within the family. Here, we show that, based on their relative affinities, CEPU-1 might be both a homo- and a heterophilic cell adhesion molecule, whereas LAMP and OBCAM act only as heterophilic cell adhesion molecules. A binding assay using recombinant IgLONs fused to human Fc showed that IgLONs are organized in the plane of the membrane as heterodimers, and we propose that IgLONs function predominantly as subunits of heterodimeric proteins (Diglons). Thus, the four IgLONs can form six Diglons. Furthermore, although singly transfected cell lines have little effect on neurite outgrowth, CHO cell lines expressing both CEPU-1 and OBCAM (Diglon-CO) inhibit neurite outgrowth from cerebellar granule cells.

Promotion of neuronal cell adhesion by members of the IgLON family occurs in the absence of either support or modification of neurite outgrowth.

The IgLONs are a family of glycosyl phosphatidyl inositol-linked cell adhesion molecules which are thought to modify neurite outgrowth and may play a role in cell-cell recognition. The family consists of LAMP, OBCAM, neurotrimin/CEPU-1 and neurotractin/kilon. In this paper we report the effect of recombinant LAMP, CEPU-1 and OBCAM, and transfected cell lines expressing these molecules, on the adhesion and outgrowth of dorsal root ganglion (DRG) and sympathetic neurones. CHO cells transfected with cDNA for CEPU-1 adhered to a recombinant CEPU-1-Fc substrate. However, DRG or sympathetic neurones only adhered to CEPU-1-Fc when presented on protein A. Although DRG and sympathetic neurones express IgLONs on their surface, both types of neurones exhibited differential adhesion to CEPU-1-Fc, LAMP-Fc and OBCAM-Fc. Neither DRG nor sympathetic neurones extended neurites on a protein A/IgLON-Fc substrate and overexpression of CEPU-1-GFP in DRG neurones also failed to stimulate neurite outgrowth on an IgLON-Fc substrate. DRG neurones adhered to and extended neurites equally on transfected and non-transfected cell lines and the recombinant proteins did not modulate the outgrowth of neurones on laminin. In contrast to previous reports we suggest that IgLONs may not have a primary role in axon guidance but may be more important for cell-cell adhesion and recognition.