Low-molecular-weight heparin (LMWH) has been used in cancer patients with venous thromboembolic complications, resulting in a higher survival rate and an inhibitory action on experimental metastasis. In the present study, human umbilical vein endothelial cells (HUVECs) were treated with LMWH for 24 h, and found that the resulting HUVECs could significantly inhibit the highly metastatic human prostate cancer cell line (PC-3M) in terms of its adhesion to the endothelium and migration across the endothelium, according to scanning electron microscopy. We also determined the elevated levels of endothelial intercellular Ca2+ concentration after the adhesion of PC-3M cells to HUVECs was greatly reduced by incubation with LMWH. Using proteomics, we surveyed the global protein changes in HUVECs after LMWH treatment and identified four downregulated proteins that were possible isoforms of cytoskeletal vimentin intermediate filaments, cartilage-derived C-type lectin, and serine/threonine protein phosphatase PP1-beta (PP-1B). LMWH affected the morphology of vimentin and the expression levels of av integrin and PP-1B in HUVECs bound to PC-3M cells. Vimentin assists in the adhesion of PC-3M cells, which was confirmed by siRNA experiments. Furthermore, the direct binding of purified vimentin protein with LMWH was detected with surface plasmon resonance (SPR) methods. However, when we used fluorescence-labeled heparin for 24 h to identify whether this binding occurred within cells, heparin was principally distributed around endothelial cells. Taken together, these findings suggest that the mono-incubation of LMWH with HUVECs could inhibit PC-3M cell adhesion to, and migration through, endothelium; LMWH's regulation of vimentin plays a role in the anti-metastatic action.
- Received March 28, 2011.
- Revision received June 30, 2011.
- Accepted June 30, 2011.
- The American Society for Pharmacology and Experimental Therapeutics