Structure-activity relationship studies of targeting ligands against breast cancer cells.

A series of LXY3 (1) analogues were designed and synthesized. Their binding affinity was demonstrated using MDA-MB-231 breast cancer cells adherence inhibition assay. Further structure-activity relationship was obtained. Analogue 29 was discovered to have 3.5-fold increase of the binding affinity. Fluorescent microscopy and in vivo and ex vivo imaging studies demonstrated that 29 is an efficient in vivo targeting agent against alpha3 integrin of MDA-MB-231 breast tumor xenograft implant.