Drug Discovery

Genetically encoded fluorescent biosensors for live cell discovery

08/03/2016 By Ali El Baya, PhD Leave a Comment

In drug discovery screening campaigns as well as in fundamental research activities, cellular parameters have to be measured and monitored in living cells regularly. Often fluorescent dyes are used to detect and follow some of the parameters. These methods are powerful, especially in screening large numbers of compounds, but have their limitations e.g. when it comes to measuring more than one parameter in the same living cell, or when specific locations in the cell shall be targeted.

To overcome these limitations and to provide tools to especially look into GPCR related signalling in the most comprehensive and detailed way currently possible, Montana Molecular have developed genetically encoded fluorescent biosensors to measure parameters such as cAMP, DAG, PIP2, Ca2+and voltage changes in living cells. [Read more…]

Cell signaling isn’t static… your cell culture shouldn’t be either

01/03/2016 By Jean-François Têtu, PhD Leave a Comment

Complex cell culture systems are emerging as key tools to improve physiological relevance of in vitro assay systems. There have been two main ways by which investigators attempt to improve mimicking of physiological conditions in cell and tissue culture. The first is to develop more complex model systems where two or more cell types are co-cultured in a 3D structure either separated by membranes or in spheroids [1]. The second is to incorporate fluidic-flow where the motion of the media itself has been shown to improve metabolic function and lifespan [2,3].

Despite the success of better recapitulating function at the cellular level using these two methods, neither of these approaches addresses the issue of the non-linear nature of the drug or toxicant exposure as is observed in an in vivo system [4]. As a result, the capacity to accurately predict in vivo pharmacokinetics and pharmacodynamics still falls short reaching at best 60-70% accuracy [5,6].

So what’s new in this area? We were interested to discover the following system, which we think will be of interest to many researchers. Let’s take a closer look at the characteristics and how it can be used. [Read more…]

Mutant PD-L1 proteins for antibody epitope mapping

16/02/2016 By Ali El Baya, PhD Leave a Comment

Cartoon of checkpoint proteins and ligands - BPS

Fig 1: Immune checkpoint proteins on T cells and their ligands on APCs and cancer cells

Knowledge about which epitopes are recognized by a blocking antibody can help researchers to develop improved antibodies for drug discovery and to better understand the mechanism of inhibition.

The binding of Programmed Cell Death Protein 1 (PD-1), one of the receptors expressed on activated T-cells (see Figure 1), to its ligands PD-L1 and PD-L2, negatively regulates immune responses. PD-1 ligands are found on most cancers, and PD-1:PD-L1/2 interaction inhibits T cell activity and allows cancer cells to escape immune surveillance.

The first therapeutic antibodies in this field have been directed against the checkpoint receptor PD-1 (Nivolumab by Bristol Myers Squibb and Pembrolizumab by Merck/MSD). The drugs have been approved for the treatment of diverse cancer types during the past years. The PD-1:PD-L1/2 pathway is also involved in regulating autoimmune responses, making these proteins promising therapeutic targets for a number of cancers, as well as multiple sclerosis, arthritis, lupus, and type I diabetes. Further research projects in this field are rapidly evolving as scientists seek to identify the next generation of therapies especially developing therapies combining different therapeutic approaches. [Read more…]

How to screen for inhibitors of PD-1 signalling in a cellular assay

09/02/2016 By Ali El Baya, PhD Leave a Comment

Fig 1: Immuno checkpoint proteins on T cell interact with ligands on APCs or cancer cells

The treatment of diseases by inducing, enhancing, or surpressing an immune response is referred to as Immunotherapy. Therapeutic manipulation of immunopathways has led to promising clinical results for the treatment of a number of diseases. The first therapeutic antibodies directed against the checkpoint receptor PD-1 have been already brought to the market (Nivolumab, Pembrolizumab) by Bristol Myers Squibb and Merck/MSD respectively, and approved for the treatment of diverse cancer types.

Today, I would like to review a versatile tool to conduct cell based inhibitor screenings on PD-1 / PD-L1/PD-L2 binding. [Read more…]

Easily customizable E3-ubiquitin ligase assay kits

08/02/2016 By Ali El Baya, PhD Leave a Comment

A ready-to-use E3 ligase activity enzymatic assay, the E3LITE kit, has been recently designed enabling researchers to screen for E3 enzyme inhibitors and potentially new therapeutical drugs. What’s it for and why is it of interest?

[Read more…]

IQF substrates for true isopeptidase/deubiquitinase activity measurement

05/02/2016 By Ali El Baya, PhD Leave a Comment

Deubiquitylating enzymes (DUBs) are promising therapeutical targets, especially in oncology (see my previous� post dedicated to this topic). Today, I’d like to introduce you to new innovative substrates to screen selectively DUB inhibitors.

[Read more…]

PXR1 knockdown boosts VitK3 anticancer effects

04/01/2016 By Philippe Fixe, PhD Leave a Comment

The anti-cancer property of the Vitamin K3 (Vitk3) was again recently studied by Dr Meng-Er Huang’s team (Curie Institute, CNRS UMR3348, Paris).
By using in vitro pro-oxydative cellular models, Dr Huang and collaborators observed a cancer-selective cytotoxicity of vitk3 in Peroxyredoxin 1 (PRDX1 aka PRX1)-deficient cancer cell lines.
To further investigate the underlying molecular mechanisms, the authors used a stably PRX1-depleted HeLa cell line (PRX1-) (vs. Control (PRX1+)) under various experimental conditions. They notably treated PRX1- and PRX1+ cell lines by vitk3 and 6 other known anticancer molecules targeting different cellular events (microtubule (vinblastine & taxol); DNA (doxorubicin & daunorubicin); DNA transcription (actinomycin D) and cell cycle (5-FU)). [Read more…]

Montelukast improves learning & memory in aging brain

15/12/2015 By Ali El Baya, PhD 2 Comments

Montelukast is a marketed drug used for asthma treatment and to relieve symptoms of seasonal allergies. It is known to function as a leukotriene receptor antagonist.

Montelukast (Data deposited in or computed by PubChem)

In a recent study in which young and old rats were treated with Montelukast, Maschallinger et al. (1) could show that the drug reduces neuroinflammation, elevates hippocampal neurogenesis and improves learning and memory in old animals. They could further demonstrate that some of these findings are mediated through an inhibitory effect on the GPR17 receptor.

GPR17 is an orphan G-protein-coupled receptor that is abundant in the CNS, and has been shown to play a key role in regulating oligodendrocyte differentiation and maturation although little has been known about the exact mechanism through which GPR17 influences myelination (2).

The most important result of their study is that cognitive function of old animals could be restored by the treatment with Montelukast. This could be shown in two different behavioral tests. While young rats have not been affected by the drug treatment, Montelukast significantly improved task learning in 20-month old rats. Non-cognitive behaviours such as anxiety-like behaviour, depression-like symptoms, exploration and locomotion as well as changes in body weight have not been affected by Montelukast treatment. Furthermore the authors found that Montelukast reduced microglia reactivity and restored hippocampal neurogenesis in old rats.

These findings might open the door for new potential pharmaceutic applications for Montelukast in treating dementia.

Modulators of GPR17

MDL29,951

Focus Biomolecules recently released Montelukast to facilitate GPR17 related research activities. Focus Biomolecules also offer 2 more GPR17 modulators through tebu-bio.

Montelukast: Leukotriene antagonist and GPR17 ligand
MDL29,951: MDL29,951 is a new, highly specific, small molecule activator of GPR17¹ that has been shown to be active in intact cells¹. The ability to specifically activate GPR17 allows for the study of the exact role GPR17 plays in the maturation of
Pranlukast
oligodendrocytes and facilitates further study of this important process.
Pranlukast: GPR17 antagonist and CysLT1 antagonist.

Interested in these modulators? Please contact us with the form below

References:

(1) J. Maschallinger et al., Structural and functional rejuvenation of the aged brain by an approved anti-asthmatic drug, Nat Commun. 6, 8466 (2015)

(2) S. Hennen et al.,Decoding signaling and function of the orphan G protein-coupled receptor GPR17 with a small-molecule agonist, Sci Signal. 6, 298 (2013)

6 active compounds to rediscover rare bacterial metabolites

11/12/2015 By Philippe Fixe, PhD 2 Comments

Microbial metabolites are a source of unequalled elements for in vitro assays. Sometimes neglected, these active molecules naturally provide a large spectrum of structural diversity for Drug discovery and antibiotics development programs. In this post, 6 metabolites and their respective properties are highlighted with the hope of refreshing our minds, a little bit, of the importance of such molecules in innovative research discovery.

[Read more…]

Deubiquitylating enzymes (DUBs) as pharmaceutical targets

10/12/2015 By Ali El Baya, PhD Leave a Comment

While it is likely that all Ubiquitin-Like proteins (UBLs) will be important for drug discovery because of these associations, Ubiquitin has been the most completely validated for this purpose by genetic, biological, and biochemical evidence. The enzymes of the Ubiquitin pathway are emerging as pioneer drug targets for many therapeutic areas.

The ubiquitin family of proteins is an important means of regulating protein trafficking, cell division, apoptosis, and metabolism in cells. Turnover of most cellular proteins is effected by ubiquitin tagging, which marks them for transport to the 26S proteasome for degradation. [Read more…]