Repositori URV

Identifier: TDX:801

Handle: https://hdl.handle.net/20.500.11797/TDX801

Authors:
Benito Alifonso, David

Abstract:
During the past decades, much progress has been made in the knowlledge of calcium signalling and how cells employ calcium in order to regulate their processes. 1D-myo-Inositol 1,4,5-trisphosphate (IP3) is a second messenger that plays an important role in intracellular calcium stores activity as well as in extracellular calcium entry. Extracellular stimuli such as hormones, neurotransmitters or growing factors (first messengers) are capable to bind to specific receptors located a the outer face of cell membrane. This bind results in an activation of Phospholipase C located on the cell membrane, which in turn catalyses the hydrolysis of phospholipids, releasing diacyl-glycerol (DAG) and IP3 (second messenger). In 1993, Takahashi et al. isolated from a Penicillium brevicompactum, culture, two potent glyconucleotides trisphosphate: Adenophostin A and B. These compounds are the most potent IP3 agonists ever reported until now, being from 10 to 100 fold times more active than IP3 itself.From a chemical point of view, Adenophostins share with IP3 a trans-diequatorial bis-phosphate moiety flanked by an hydroxyl group at C-2'.(see Figure) Moreover, Adenophostins are resistent to enzymes that metabolize IP3 such as IP3-phosphatase and IP3-kinase. Many Adenophostin analogues have been synthesized in order to elucidate strucural features responsible of Adenophostin activity, and to obtain more active compounds. However, until now, only few analogues has overcome IP3 activity and none of them has reach Adenophostine activity. Structure-activity-relationship studies has allowed to design a pharmacophore model for Adenophostin A. Main features of this model are: The trans-diequatorial bis-phosphate moiety flanked by 2''-OH, which is a key point for Adenophostin biological activity,