Nicolas Pietrancosta

Substituted thiazolamide coupled to a redox delivery system: a new γ-secretase inhibitor with enhanced pharmacokinetic profile

Inhibition of gamma-secretase, one of the enzymes responsible for the cleavage of the amyloid precursor protein (APP) to produce pathogenic A beta peptides, is an attractive approach for the treatment of Alzheimers disease. We have designed a new gamma-secretase thiazolamide inhibitor bearing a dihydronicotinoyl moiety as Redox Delivery System which allows specific delivery of the drug to the brain. Through, on the one hand, A beta peptide production measurements by specific in vitro assays (gamma-secretase Cell Free assay and Cell Based assay on HEK 293 APP transfected cells) and, on the other hand, pharmacokinetic studies on animal models, the new inhibitor shows a good pharmacokinetic profile as well as a potent gamma-secretase inhibitory activity in vitro. From the obtained results, it is expected that drug will be mainly delivered to the CNS with low diffusion in the peripheral tissues. Consequently the side effects of this gamma-secretase inhibitor on the immune cells could be reduced.

A new Met inhibitory-scaffold identified by a focused forward chemical biological screen

The receptor tyrosine kinase Met is crucial for the genetic program causing cancer progression and metastasis. Its nodal function during aggressiveness and resistance acquisition poses Met inhibition as an obligatory step in anti-cancer targeted therapy. Here, we applied a Met-focussed forward chemical biological screen to discover new agents antagonizing Met-triggered biological functions. The identified new scaffold, JLK1360, has a dual mechanism of action towards Met: it impairs Met signalling and also prevents its restoration after degradation. Docking and molecular dynamics provide evidences on the interacting mode of JLK1360 within the Met ATP-binding pocket. Moreover, computational and biochemical studies also highlighted that JLK1360 has a good degree of selectivity towards Met than other RTKs tested. Altogether, these findings demonstrate that the approach we have applied is a powerful strategy to identify compounds with combined properties towards a chosen target. Our studies show how integration of chemistry, biology and computational analysis can provide robust strategies to identify new inhibitory scaffolds suitable for further development of anti-cancer targeted therapies.

Enhanced delivery of γ-secretase inhibitor DAPT into the brain via an ascorbic acid mediated strategy

Inhibition of gamma-secretase, one of the enzymes responsible for the cleavage of the amyloid precursor protein (APP) to produce pathogenic Abeta peptides, is an attractive approach for the treatment of Alzheimers disease. We designed a gamma-secretase inhibitor bearing an ascorbic acid moiety which allows a specific delivery of the drug to the brain. Through, on the one hand, Abeta peptide production measurements by specific in vitro assays (gamma-secretase cell free assay and cell based assay on HEK 293 APP transfected cells) and on the other hand through pharmacokinetic studies on animal models, the new inhibitor shows a good pharmacokinetic profile as well as a potent gamma-secretase inhibitory activity in vitro. From the obtained results, it is expected that drug will be mainly delivered to the CNS with a low diffusion in the peripheral tissues. Consequently the side effects of this gamma-secretase inhibitor on the immune cells could be reduced.

Prospects for the Resistance to HIV Protease Inhibitors: Current Drug Design Approaches and Perspectives

One of the major challenges raised by HIV chemotherapy is the insurgence of viral resistance to drugs. Resistance to antiviral therapy has been observed for each of the different classes of anti-viral drugs: nucleoside reverse-transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors. The crucial question for AIDS drug research community is: Should we continue the search of new anti-HIV drugs which can overcome HIV resistance insurgence or should we consider resistance to anti-HIV drugs as a futile challenge? This review, focussed specifically on HIV antiprotease drugs, highlights the different strategies which have been developed to design new anti-protease drugs which could overcome HIV resistance, and also reviews the different classes of compounds (peptidomimetic or non-peptidomimetic) actually under investigation in order to face the problem of HIV resistance to drug.

Synthesis of New Substituted 4,5-Dihydro-3H-spiro[1,5]-benzoxazepine-2,4′-piperidine and Biological Properties

The reduction of substituted spiro-piperidinyl chromanone oximes with DIBAH reagents has been known to afford the corresponding substituted 4,5-dihydro-3H-spiro[1,5]-benzoxazepine-2,4′-piperidine. The position and electronic effects of the substituents on the aryl moiety control the observed rearrangement. Spiro-benzoxazepine analogue 5j represents a key intermediate for the creation of a library of diverse potential bioactive drugs. With three functional groups that could be selectively and orthogonally protected, many different substituents can be introduced. The obtained analogues were assayed as the possible aspartyl protease inhibitors HIV protease (HIV-1), and β-secretase (BACE-1).

Design of β-secretase inhibitors by introduction of a mandelyl moiety in DAPT analogues

We report the synthesis of two series of compounds with 3,5-difluoromandelyl-alanyl or 3,5-difluorophenylacetyl-alanyl backbones coupled to various heterocyclic or peptidic moieties. These two series of compounds were evaluated for their inhibitory properties on β-secretase (BACE-1) enzymatic assay, a target enzyme for Alzheimer’s disease (AD) pathology. We found that both diastereomers obtained from the racemic mixture 7 of the coumarin derivative bearing a mandelyl moiety were the most potent BACE-1 inhibitors studied in this work (IC50 = 1 × 10−6 M). Analysis of the obtained results led to the hypothesis that introduction of a difluoromandelyl residue in place of a difluorophenylacetyl moiety may induce β-secretase inhibitory activity.

Identification of Privileged Scaffolds from a Diversified Chemical Library forβ-Secretase Inhibition

A privileged structure has been identified within the 1,300-member diversified library by rational selection of the compounds to be tested prior to the screening towards enzymatic β-secretase (BACE-1) assay. The identified hexahydrobenzothiazole privileged structure has been optimised and a preliminary structureactivity study has been performed.