Synthesis and Biological Evaluation of Cyclic Analogues from Nitrone LQB-278: A New Potential Antileukemia Compound.

BACKGROUND/AIM:A new set of LQB-nitrones and analogues was synthesized to evaluate anticancer activity based on the substitution of the terpenyl moiety of the antileukemic compound LQB-278 by the conformationally restricted cinnamyl ether. MATERIALS AND METHODS:A structure-activity relationship study was performed in vitro on Jurkat cells to screen the antileukemic activity of LQB-nitrones and analogues and elucidate the mechanisms of action of the most active derivatives. RESULTS:The cynamyl ramification and its ortho position aldehyde substitution improved the antileukemic activity. Three compounds showed an in vitro antiproliferative action, but only 5b induced apoptosis. Analysis of the molecular mechanisms showed increased expression of the cell cycle inhibitor p21CIP1/WAF1/Sdi1, caspase 3, Fas receptor, and Bax/Bcl-2 ratio. CONCLUSION:The cinnamyl derivative 5b (LQB-461) presented higher antileukemic effects than the prototype terpenyl nitrone, inducing Jurkat cell death by activating both extrinsic and intrinsic pathways of apoptosis. Therefore, this compound is a new promising candidate drug against leukemia.