Inhibition of BC3H-1 cell growth by heparin is related to decreased mitogenic signalling

We examined the effect of heparin and heparin fragments on BC3H-1 muscle cell proliferation. Heparin significantly inhibited BC3H-1 cell growth and this inhibitory effect was related to the ability of heparin to bind to cell surface; low molecular weight heparins were poorly efficient in binding and inhibiting proliferation. Analysis by gel filtration of heparin bound to cell surface showed selective binding of the high molecular weight fraction. Heparin inhibited serum-stimulated incorporation of [3H]thymidine; this effect, however, was only evident when heparin was administered concomitantly with serum. Similarly, heparin inhibited serum-induced inositol lipid turnover only when present with serum. Heparin fragments unable to inhibit cell growth did not affect the metabolism of inositol lipids. Taken together these data suggest that heparin inhibits cell growth by interfering with growth factor-mediated mitogenic signalling.