UNIQUE EXPRESSION OF INTEGRIN FIBRONECTIN RECEPTORS IN HUMAN NEUROBLASTOMA CELL-LINES

Cultured human neuroblastoma cells can be classified morphologically into 3 types: neuroblastic (N), intermediate (I) and substrate adherent (S). Neuroblastoma cells of all types were found to attach and display distinct morphological characteristics on fibronectin, with S-type cells attaching better than N-type cells. Studies of the expression of integrin fibronectin receptors (alpha-3-beta-1, alpha-4-beta-1, alpha-5-beta-1 and alpha-V-beta-1) were carried out using a total of 26 morphologically distinct cell lines and their subpopulations. Fluorescence-activated cell sorting (FACS) analysis and immunoprecipitation revealed that all S-type cells expressed abundant alpha-5-beta-1, while N-type cells barely expressed this molecule. Although alpha-3-beta-1 expression of S-type cells was also higher than that of N-type cells, some N-type cells had significantly increased levels of this molecule. Alpha-4-beta-1 was found to be randomly expressed. All cell lines tested expressed alpha-V-beta-1. Human neuroblastoma cells, the majority of which are N-type cells with very low alpha-5-beta-1 expression, are also contrasted with other childhood cancer cells (rhabdomyosarcoma, Ewing's sarcoma, and glioma), all of which expressed high levels of alpha-5-beta-1. The characteristic expression of integrin fibronectin receptors may account for the clinically unique tumor behavior, and the immunohistochemical staining for integrins may become a useful alternative to conventional histology in differential diagnosis and a marker for prognosis in neuroblastoma.