A Synergetic Screening Approach with Companion Effector for Combination Therapy: Application to Retinoblastoma

For many cancers, the lack of potency and the toxicity of current drugs limits the dose achievable in patients and the efficacy of treatment. Among them, retinoblastoma is a rare cancer of the eye for which better chemotherapeutic options are needed. Combination therapy is a compelling approach to enhance the efficacy of current treatment, however clinical trials to test rationally designed combinations of approved drugs are slow and expensive, and limited by our lack of in-depth knowledge of drug specificity. Since many patients already turn to nutraceuticals in hopes of improving their condition, we hypothesized that certain approved drugs could potentially synergize with widely consumed supplements. Following this hypothesis, we devised an alternative screening strategy aimed at taking advantage of a bait compound such as a nutraceutical with potential therapeutic benefits but low potency, by screening chemical libraries for approved drugs that synergize with this companion effector. As a proof of concept, we sought to identify approved drugs with synergetic therapeutic effects toward retinoblastoma cells in combination with the antioxidant resveratrol, popular as a supplement. We systematically tested FDA-approved drugs and known bioactives seeking to identify such pairs, which led to uncovering only a few additive combinations; but to our surprise, we identified a class of anticancer drugs widely used in the clinic whose therapeutic effect is antagonized with resveratrol. Our observations could explain in part why some patients do not respond well to treatment. Our results validate this alternative approach, and we expect that our companion effector strategy could significantly impact both drug discovery and the nutraceutical industry.     

La dysfonction érectile, un marqueur précoce d’atteinte cardio-vasculaire

Erectile dysfunction (ED) affects approximately 100 million men in the world and 50% of men between the ages of 40 and 70 years. The commonest cause is a vascular disorder of penile arteries. ED may therefore be a an early marker of cardiovascular disease (CVD). The main arguments in favour of this assertion are primarily epidemiological, but also pathophysiological, as control of cardiovascular risk factors such as smoking, obesity and hypertension may prevent not only CVD, but also ED. This relationship is particularly strong in diabetic patients, in whom ED can be considered to be an element able to identify patients at risk of asymptomatic heart disease. From a pathophysiological point of view, small calibre penile vessels present signs of obstruction earlier than larger vessels because they are more sensitive to even minor haemodynamic changes. There is also a significant correlation between the severity of ED and the number of vessels affected in patients with coronary artery disease. Endothelial dysfunction is the common denominator underlying these diseases and therefore represents a major cause of ED. Preliminary studies have shown that PDE-5 inhibitors can reduce symptoms, improve exercise tolerance, and reduce endothelial dysfunction in patients after cardiac arrest and in diabetics. In the years to come, ED may therefore be added to the classical cardiovascular risk factors and could characterize a population with an increased risk of coronary artery disease.     

Phenylthiocarbamide taste sensitivity and its relationship to growth variation

The hypothesis that there is a relationship between the tasting polymorphism and growth variation was tested on a sample of 425 Negro elementary school children. Twenty-seven non-tasters were found by testing with impregnated papers; 13 were male, 14 female, indicating no sex differences in this group. Matchedpair comparisons indicated no differences in weight, a tendency for tasters to be taller, and a stronger tendency for tasters of both sexes to be skeletally more mature. It was felt that the tendency for tasters to be taller might reflect their more advanced maturation status. The relationship to skeletal maturation might be indicative of the decreased thryoid activity found in other studies of phenylthiocarbamide tasting.     

Genetic recombination in a chloramphenicol-producing strain of Streptomyces species 3022a.

Mutation with ultraviolet light and chemical mutagens yielded strains with auxotrophic and streptomycin-resistance markers. These were used to show the existence of genetic recombination in Streptomyces species 3022a and to construct a linkage map for 17 marker loci.