More recently, affinity chromatography coupled to mass spectrometry allowed us to perform a large-scale identification of yeast
and mouse AICAR-binders, many of which being conserved through species (our unpublished results). The next step is to validate the binders as true AICAR targets in vivo. Interestingly, it was recently found that the yeast Inhibitors,research,lifescience,medical AMPK (Snf1) is activated by ADP but not by AMP , thereby accounting for the fact that AICAR apparently does not activate the yeast AMPK, as presumed from the transcriptome signature . Yeast is therefore an appealing simple eukaryotic model to study AMPK-independent AICAR effects. Aside from AMPK, AICAR modulates several enzymes such as glucokinase  or glycogen phosphorylase . In a few cases, direct binding of AICAR to specific proteins has been reported, including phosphofructokinase (PFK) and fructose-1,6-biphosphatase Inhibitors,research,lifescience,medical (F1,6-BPase) which are inhibited
in vitro by AICAR [45,46]. AICAR interaction with Hsp90 was also demonstrated and many client proteins of Hsp90 were found destabilized in vivo in the presence of AICAR . Both PFK and Hsp90 contribute to important functions Inhibitors,research,lifescience,medical for tumor growth and could thus be involved in the anti-proliferative effects of AICAR, which was reported for several tumor cell lines (such as PC-3, MCF-7,C6 glioma, U87MG, K-562 and CEM) . It is noteworthy that, while AICAR replaces AMP in AMPK , it competes with ATP in Hsp90 . It will be interesting to determine whether all AICAR targets are nucleotide-binding proteins. 6. Effects of AICAR on Whole Organisms Inhibitors,research,lifescience,medical There are few studies showing effects of AICAR on whole organisms and in most cases
the protein effectors are not clearly identified, although AICAR was chosen in these studies for its AMPK-activating properties. AICAR feeding of Caenorhabditis elegans selleck resulted in decreased fat storage as would be predicted when AMPK is activated . Drosphila melanogaster fed with AICAR were more resistant Inhibitors,research,lifescience,medical to anoxia/re-oxygenation injuries . AICAR has been found to reduce myocardial ischemic injury in several these models (rat, mice, rabbit, dog…)  and in humans . Injection of AICAR to mice resulted in a hypoglycemic effect . Strikingly, sedentary mice fed with AICAR showed increased endurance . AICAR was renamed “the exercise pill” and subsequently suspected of human misusage as a doping agent. AICAR is not currently approved by FDA and has only been used in a very few investigations in humans [55,56,57]. 7. Conclusion AICAR is a highly promising pharmacophore showing various effects on multiple functions. In the future, AICAR or derivatives could represent key molecules for several diseases including heat induced sudden death, cytochrome c-oxidase deficiencies, cancer and other pathologies associated with muscle wasting.