Camptothecins in tumor homing via an RGD sequence mimetic.

ABSTRACT

A RGD peptide mimetic was conjugated to four camptothecins, with the purpose to improve their therapeutic index. The conjugate derivatives were evaluated against two tumor cell lines, one overexpressing integrins (human ovarian carcinoma, A2780) and a second one with a low integrin expression (human prostate cancer, PC3). The in vitro screening was completed with the adhesion behavior to vitronectin. Compound 8 (ST7456CL1) was selected for the in vivo investigation after stability tests over 24h, in PBS solution and in rat plasma, and compared to irinotecan. The former showed a prolonged half-life.