HEPARAN SULPHATE HEPARIN GLYCOSAMINOGLYCANS WITH STRONG AFFINITY FOR THE GROWTH-PROMOTER SPERMINE HAVE HIGH ANTIPROLIFERATIVE ACTIVITY/

Depletion of intracellular polyamine pools inhibits cell proliferation . Polyamine pools are maintained by intracellular synthesis and by upt ake from the extracellular environment, It may be expected that cation ic polyamines are sequestered by the polyanionic glycosaminoglycan sub stituents of extracellular proteoglycans. Moreover, highly sulphated h eparin-related glycans inhibit growth of human embryonic lung fibrobla sts. We have therefore investigated interactions between polyamines an d heparin-related glycosaminoglycans. Affinity chromatography of vario us polyamines on heparin-agarose indicated that spermine was the only polyamine that bound efficiently to this type of glycan, By using equi librium dialysis we found that spermine binds to a highly sulphated he paran sulphate/ heparin preparation with a dissociation constant of 3. 7 x 10(-5) M. Enzymatic degradation of heparan sulphate using three di fferent heparan sulphate/heparin lyases, separately or in combination and in the absence or presence of spermine, was used to generate sperm ine-binding and degradation-protected oligosaccharides. As indicated b y chromatographic and electrophoretic analysis a size- and charge-hete rogeneous collection was obtained, However, protected oligosaccharides derived from antiproliferative heparan sulphates were inactive. Highl y sulphated, antiproliferative heparan sulphates were subfractionated on spermine-agarose yielding high-affinity material with increased ant iproliferative activity, A very potent material was obtained from pig skin, Although there was generally a clear correlation between high sp ermine-affinity and strong growth-inhibition, no correlation with sulp hate content or oligosaccharide mapping patterns could be detected, Be ef lung heparan sulphate comprised naturally occurring fragments of ei cosasaccharide size with substantially increased specific activity, As these fragments were longer than oligosaccharides generated by enzyma tic degradation in the presence of spermine (hexa- to tetradecasacchar ide), multiple spermine-binding sites in tandem may be necessary to in duce antiproliferative activity.