THE EXPRESSION OF THE LDL RECEPTOR-RELATED PROTEIN (LRP) CORRELATES WITH THE DIFFERENTIATION OF HUMAN NEUROBLASTOMA-CELLS

The low density Lipoprotein receptor-related protein (LRP) has been lo calized in human brain at the level of neurons, astrocytes and along c apillary membranes. It is a multifunctional receptor responsible for b inding and internalization of lipoproteins enriched with apoliprotein E, lipoprotein lipase, protease-alpha(2)macroglobulin complexes and pl asminogen activator-inhibitor complexes. LRP expression is observed in cells involved in Alzheimer's disease, neoplastic transformation and tissue repair. Moreover, its synthesis is modulated during brain devel opment. In this study we used the SK-N-AS human neuroblastoma cell lin e as a model system to study LRP expression during cellular differenti ation induced by phorbol esters, retinoic acid and interferon gamma. S ince LRP plays a major role in the regulation of lipid metabolism, the decreased levels of LRP measured by immunofluorescence, western blot and PCR on differentiated neuroblastoma cells may be the consequence o f the lower requirements of cholesterol and lipids of differentiated c ells in relation to their reduced mitotic index. (C) 1997 Elsevier Sci ence B.V.