Jean-Yves Puy

Molecularly imprinted polymer for analysis of zidovudine and stavudine in human serum by liquid chromatography-mass spectrometry

A molecularly imprinted polymer (MIP) using zidovudine (AZT) as template and methacrylic acid as monomer was prepared. The synthesis of the MIP was performed in acetonitrile. The synthesized material was then tested for the solid-phase extraction of AZT from different media (pure organic solvents and hydro-organic mixtures). An optimised procedure was developed for the selective extraction of AZT with a recovery of 96% using the MIP and only 3% on a non-imprinted polymer used as control polymer. A specific capacity of 0.2 micromol g(-1) was determined. The specificity of the MIP was evaluated by studying the retention behaviour of two others nucleoside analogues. The feasibility of the MIP to selectively extract AZT and stavudine (d4T) from human serum was also demonstrated with recoveries of 80 and 85% respectively. The lower limit of quantification (LLOQ) and the lower limits of detection (LLOD) for AZT were 5.10(-7) and 10(-7) M respectively.

The cytosolic 5’-nucleotidase cN-II lowers the adaptability to glucose deprivation in human breast cancer cells

The cytosolic 5’-nucleotidase cN-II is a highly conserved enzyme implicated in nucleotide metabolism. Based on recent observations suggesting additional roles not directly associated to its enzymatic activity, we studied human cancer cell models with basal or decreased cN-II expression. We developed cancer cells with stable inhibition of cN-II expression by transfection of shRNA-coding plasmids, and studied their biology. We show that human breast cancer cells MDA-MB-231 with decreased cN-II expression better adapt to the disappearance of glucose in growth medium under normoxic conditions than cells with a baseline expression level. This is associated with enhanced in vivo growth and a lower content of ROS in cells cultivated in absence of glucose due to more efficient mechanisms of elimination of ROS. Conversely, cells with low cN-II expression are more sensitive to glucose deprivation in hypoxic conditions. Overall, our results show that cN-II regulates the cellular response to glucose deprivation through a mechanism related to ROS metabolism and defence.

Synthesis and evaluation of a molecularly imprinted polymer for selective solid-phase extraction of irinotecan from human serum samples.

A molecularly imprinted polymer (MIP) was synthesized by non-covalent imprinting polymerization using irinotecan as template. Methacrylic acid and 4-vinylpyridine were selected as functional monomers. An optimized procedure coupled to LC-PDA analysis was developed for the selective solid-phase extraction of irinotecan from various organic media. A specific capacity of 0.65 µmol·g−1 for the MIP was determined. The high specificity of this MIP was demonstrated by studying the retention behaviour of two related compounds, camptothecin and SN-38. This support was applied for the extraction of irinotecan from human serum samples.

New insights for the preparation of cytidine containing nucleotides using a soluble ether-linked polyethylene glycol support

We proposed an improved methodology for soluble PEG-supported synthesis of 5′-nucleotide derivatives from cytidine using a carboxylethoxy linker. Compared to our previous work, no by-product is formed during cleavage from the support and dialysis is not required anymore for purification.