New 1,4-dihydropyridines conjugated to furoxanyl moieties, endowed with both nitric oxide-like and calcium channel antagonist vasodilator activities

A series of 4-phenyl-1,4-dihydropyridines substituted at the ortho and meta positions of the phenyl ring with NO-donating furoxan moieties and their non-NO-releasing furazan analogues were synthesized and pharmacologically characterized. The vasodilator activities of these compounds were evaluated on rat aorta and expressed as EC50 values or as EC50iGC values when obtained in the presence of inhibitors of guanylate cyclase methylene blue (MB) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Affinities to 1, 4-DHP receptors on Ca2+ channels, expressed as IC50 values, were determined through displacement experiments of [3H]nitrendipine on rat cortex homogenates. A linear correlation between IC50 and EC50 values was found for compounds unable to release NO. EC50calcd values for derivatives containing NO-donor moieties, expression of the Ca2+-blocking component of their vasodilator activity, were interpolated on this linear regression. They showed a good correspondence with EC50iGC values determined in the presence of soluble guanylate cyclase inhibitors. Analysis of EC50iGC/EC50 ratios provided a useful tool to distinguish well-balanced hybrids from derivatives biased toward Ca2+-blocking or NO-dependent vasodilator activity. A detrimental effect on affinity to the 1, 4-DHP receptor, due to substitution at the ortho and meta positions of the 4-phenyl ring, was observed. SAR to explain this effect is proposed.     

Basic Science with Preclinical Models to Investigate and Develop Liquid Biopsy: What Are the Available Data and Is It a Fruitful Approach?

The molecular analysis of circulating analytes (circulating tumor-DNA (ctDNA), -cells (CTCs) and -RNA (ctRNA)/exosomes) deriving from solid tumors and detected in the bloodstream—referred as liquid biopsy—has emerged as one of the most promising concepts in cancer management. Compelling data have evidenced its pivotal contribution and unique polyvalence through multiple applications. These data essentially derived from translational research. Therewith, data on liquid biopsy in basic research with preclinical models are scarce, a concerning lack that has been widely acknowledged in the field. This report aimed to comprehensively review the available data on the topic, for each analyte. Only 17, 17 and 2 studies in basic research investigated ctDNA, CTCs and ctRNA/exosomes, respectively. Albeit rare, these studies displayed noteworthy relevance, demonstrating the capacity to investigate questions related to the biology underlying analytes release that could not be explored via translational research with human samples. Translational, clinical and technological sectors of liquid biopsy may benefit from basic research and should take note of some important findings generated by these studies. Overall, results underscored the need to intensify the efforts to conduct future studies on liquid biopsy in basic research with new preclinical models.