Terminally Alkylated Heparin. 2. Potent Antiproliferative Agent for Vascular Smooth Muscle Cells

Abstract

The antiproliferative activity of alkylated heparin, in which the terminal end of heparin is derivatized with an alkyl group (butyl, octyl, lauryl, stearyl), was examined using vascular smooth muscle cells. The proliferation of cells, which were growth-arrested prior to addition of heparin, was inhibited in proportion to both increase in the chain length of the alkyl group of alkylated heparin and alkylated heparin concentration in the serum-containing medium. The antiproliferative activity of stearyl group derivatized heparin was significantly stronger than that of nonmodified heparin. Little proliferation was observed at high dose (500 microg/mL). Confocal laser scanning microscopic observation indicated that alkylated heparin was accumulated on the cell membranes at an early incubation time, followed by homogeneous distribution of intracellular space. The therapeutic potential of alkylated heparin for preventing restenosis after balloon angioplasty is discussed.

Intracellular Delivery of Heparin Complexed with Chitosan-g-Poly(Ethylene Glycol) for Inducing Apoptosis

“…It was found that chitosan-g-PEG was non-toxic to the cancer cells, indicating that the cationic polymer itself was not responsible for the cell death. Since heparin is a highly negatively charged macromolecule, the absorptive endocytosis of heparin across the cell membrane would not occur (26). It was most likely that the chitosan-g-PEG/heparin polyelectrolyte complex micelles entered the cell by nonspecific adsorptive endocytosis, inducing the cancer cell death more efficiently than free heparin alone.…”

Increase in the growth inhibition of bovine pulmonary artery smooth muscle cells by an O-hexanoyl low-molecular-weight heparin derivative

“…Periodate-oxidized heparin fragments were converted to the tributylammonium salt using a modification of previously described conditions. 17,18 Briefly, heparin fragments (10 g) were dissolved in water (50 mL) and passed through a column (300 mL) of Dowex 50WX8 (H + ) cation-exchange resin. The pH of the eluent ($500 mL) was adjusted to pH 6.0 using Bu 3 N ($25 mL, 0.1 mol).…”

“…The derivatives of tributylammonium salt of periodate oxidized heparin fragments were acylated with hexanoic anhydride using a modification of methods previously described. 17,18 Briefly, the dry tributylammonium salt (12 g), dissolved in dry DMF (110 mL) was cooled to 0°C under an argon atmosphere. 4-Dimethylaminopyridine (0.7 g, 5.7 mmol), hexanoic anhydride (26.2 mL, 0.1 mol), and Bu 3 N (27 mL, 0.1 mol) were successively added in single portions, and the reaction was allowed to proceed under Ar at room temperature for 24 h. After cooling to 0°C, 5% NaHCO 3 in water (230 mL) was gradually added, and the solution was stirred at room temperature for 48 h. Excess NaHCO 3 was eliminated by slow, dropwise addition of 1 N HCl ($200 mL) until a pH of 4.0 was reached, and then the pH was readjusted to 7.0 with 1 N NaOH ($150 mL).…”

“…Matsuda and co-workers have prepared a terminally alkylated heparin by treatment of the heparin sodium salt with an oxidizing agent to generate a lactone ring at its terminal end and subsequently reacted it with an alkylamine group, containing 4-18 carbons, to synthesize the alkylated heparin. 16,17 They found that increasing the alkyl group chain length reduced the proliferation rate of vascular smooth muscle cells.…”

Antiangiogenic and Apoptotic Properties of a Novel Amphiphilic Folate-Heparin-Lithocholate Derivative Having Cellular Internality for Cancer Therapy

“…Furthermore, it is still hard to determine the ultimate effect of heparin on cancer progression due to the wide variety of its physiological activities (2,4,10). Although several effective approaches for using sulfated oligosaccharides (11) or chemically modified heparins, such as polystyrene bearing and steroid conjugated heparin (12,13), terminally alkylated heparin (14), have been investigated as angiogenesis inhib-itors or anti-tumor agents, most of technologies were addressed on only angiogenesis, and they required high doses causing the negative effects discussed above.…”