Sigma receptor-mediated targeted delivery of anti-angiogenic multifunctional nanodrugs for combination tumor therapy.

The potential of low molecular weight heparin (LMWH) in anti-angiogenic therapy has been tempered by poor in vivo delivery to the tumor cell and potentially harmful side effects, such as the risk of bleeding due to heparin's anticoagulant activity. In order to overcome these limitations and further improve the therapeutic effect of LMWH, we designed a novel combination nanosystem of LMWH and ursolic acid (UA), which is also an angiogenesis inhibitor for tumor therapy. In this system, an amphiphilic LMWH-UA (LHU) conjugate was synthesized and self-assembled into core/shell nanodrugs with combined anti-angiogenic activity and significantly reduced anticoagulant activity. Furthermore, DSPE-PEG-AA-modified LHU nanodrugs (A-LHU) were developed to facilitate the delivery of nanodrugs to the tumor. The anti-angiogenic activity of A-LHU was investigated both in vitro and in vivo. It was found that A-LHU significantly inhibited the tubular formation of human umbilical vein endothelial cells (HUVECs) (p<0.01) and the angiogenesis induced by basic fibroblast growth factor (bFGF) in a Matrigel plug assay (p<0.001). More importantly, A-LHU displayed significant inhibition on the tumor growth in B16F10-bearing mice in vivo. The level of CD31 and p-VEGFR-2 expression has demonstrated that the excellent efficacy of antitumor was associated with a decrease in angiogenesis. In conclusion, A-LHU nanodrugs are a promising multifunctional antitumor drug delivery system.