Natural Fragments in the Design of Multitargeted Ligands

The inherent redundancy and robustness in many biological networks and pathways implies that the inhibition of a single target might fall short of producing the desired therapeutic effect. This situation is particularly emphasized in highly complex diseases such as dysfunctions of the metabolic, cardiovascular, cell signaling, and central nervous systems [1]. A challenging opportunity for surmounting this problem is offered by the development of agents able to modulate multiple but limited targets simultaneously (multitargeted ligands). The most common strategies used to the design such agents rely either on balancing multiple activities of known promiscuous leads by error and trial structural modifications, or by joining two molecules to form hybrids, chimerae, or high molecular weight conjugates. However, both strategies tend to generate large molecules with detrimental physiochemical properties [2]. A re-evaluation of the modern principles of fragment-based design is here presented, which opens new perspectives to the design of multitargeted ligands as biological tools and potential leads for systems biology-based diseases, with a special emphasis on cancer. The preliminary results of the methodology are described, which integrates multivariate methods and molecular modeling with biostructural information available from naturally occurring, promiscuously active products, in an effort to anticipate the identification of multitargeted proapoptotic modulators in early and less expensive stages of the drug design. References [1] Pujol, A.; Mosca, R.; Farrés, J.; Aloy, P. Trends Pharmacol. Sci., 31, 115-123 (2010). [2] Morphy, R. Drug. Disc. Today, 12, 156-160 (2007).