Synthesis and biological evaluation of DIDS analogues as efficient inhibitors of RAD51 involved in homologous recombination.

RAD51 is a pivotal protein of the homologous recombination DNA repair pathway, and is overexpressed in some cancer cells, disrupting then the efficiency of cancer-treatments. The development of RAD51 inhibitors appears as a promising solution to restore these cancer cells sensitization to radio- or chemotherapy. From a small molecule identified as a modulator of RAD51, the 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), two series of analogues with small or bulky substituents on the aromatic parts of the stilbene moiety were prepared for a structure-activity relationship study. Three compounds, the cyano analogue (12), and benzamide (23) or phenylcarbamate (29) analogues of DIDS were characterized as novel potent RAD51 inhibitors with HR inhibition in the micromolar range.

Comparative Analysis of Culture Conditions for the Optimization of Carotenoid Production in Several Strains of the Picoeukaryote Ostreococcus.

Microalgae are promising sources for the sustainable production of compounds of interest for biotechnologies. Compared to higher plants, microalgae have a faster growth rate and can be grown in industrial photobioreactors. The microalgae biomass contains specific metabolites of high added value for biotechnology such as lipids, polysaccharides or carotenoid pigments. Studying carotenogenesis is important for deciphering the mechanisms of adaptation to stress tolerance as well as for biotechnological production. In recent years, the picoeukaryote Ostreococcustauri has emerged as a model organism thanks to the development of powerful genetic tools. Several strains of Ostreococcus isolated from different environments have been characterized with respect to light response or iron requirement. We have compared the carotenoid contents and growth rates of strains of Ostreococcus (OTTH595, RCC802 and RCC809) under a wide range of light, salinity and temperature conditions. Carotenoid profiles and productivities varied in a strain-specific and stress-dependent manner. Our results also illustrate that phylogenetically related microalgal strains originating from different ecological niches present specific interests for the production of specific molecules under controlled culture conditions.