established for high throughput screening of large chemical libraries. One series of pharmacophore was identified and optimized for their capacity to inhibit binding, uptake and accumulation of ox-LDL by THP1 cells. Two members of this series, named AP5055 and AP5258 produced a significant inhibition of foam cells formation with IC50 of 100 nM and 500 nM respectively and were selected for further studies. This inhibition was observed at constant nucleus number. One analog of the same series, AP5156, with similar chemical structure was inactive indicating the order DPC-681 presence of a structure-function relationship within this chemical series. HEK-CD36 cells interacted with both LCFA and oxidized lipoprotein particles, stored these particles and accumulated lipid rich vesicles in a CD36-YYA-021 dependent way. This cell line was further utilized to explore the anti-CD36 activity of these chemical entities. When performed at 37uC, lipid vesicles accumulation by these cells was significantly inhibited by both AP5055 and AP5258 with IC50 similar to that observed with THP1 cells. Similarly, both AP5055 and AP5258 inhibited palmitate cellular transfer to a level comparable to that observed with nontransfected wild type cells. Both inhibitors produced a dose dependent inhibition of CD36-dependent binding to the membrane of these cells with IC50 of 160.1 mM and 561 mM respectively. The analog AP5156 used as a negative control, had no effect on this binding, up to a concentration of 1024 M. The compounds AP5055 and AP5258 were then utilized to further explore the receptor inhibitor activity of this chemical series. Different experiments indicated that these inhibitors are receptor rather than oxLDL directed. First, the compounds did not affect the electrophoretic mobility of the complex at any concentration tested as illustrated in Figure 3A. Second, both AP5055 and AP5258 had no effect on the CD36-independent binding as observed with wild type HEK cells. This level of CD36- independent binding never exceeded 15 on the wt HEK cells. Third, when bound biotynilated-oxLDL was affinity cross-linked to the HEK-CD36 membrane, then immunoprecipitated with an anti-biotin monoclonal antibody, and analyzed by western blotting with an anti-CD36 monoclonal antibody, after reduction to quanti
