Abstract
Rational designed lipid-drug derivatives provide a favorable approach to improve the druggability of highly hydrophobic prototypes. It has been regarded as common sense that good cytotoxicity is the guarantee of superior anticancer efficacy for candidate derivatives screening. Here, we established two lipid-drug derivatives with different bridge bonds (ester bond and mono thioether bond) linking docetaxel and linoleic acid. The IC50 of DSL NPs (DTX-S-LA nanoparticles) and DL NPs (DTX-LA nanoparticles) were 4.02 and 209.6 ng/mL (DTX equivalent concentration), respectively. However, DL NPs unexpectedly showed stronger tumor inhibition abilities than DSL NPs. To explain the non-positive correlation between cytotoxicity and anticancer efficacy, more experiments were carried out in depth. Remarkably, the drug release studies in blood and PK study both suggested that the DL NPs were more stable to remain the structural integrity in circulation, which resulted in more accumulation in tumor sites. As verified by the bio-distribution study, DL NPs performed a superior target effect than DSL NPs in tumors. Our data indicated that the biological fates of so-called smart bond inserted derivatives in vivo are complicated, thus, simple cytotoxicity is not enough for derivatives screening, and the comprehensive understanding of both in vitro and in vivo behaviors is essential.
Direct comparison of two kinds of linoleic acid-docetaxel derivatives: in vitro cytotoxicity and in vivo antitumor activity