FUNCTIONAL THROMBIN RECEPTOR PAR1 IN PRIMARY CULTURES OF HUMAN GLIOBLASTOMA CELLS

IN this study we investigated primary cultures obtained from two gliob lastomas surgically removed from a 64-year-old man and a 50-year-old w oman, respectively. The presence of the tethered ligand thrombin recep tor PAR1 (protease-activated receptor 1) in these cells was demonstrat ed at the level of receptor binding by using immunofluorescence studie s with the monoclonal anti-PAR1 antibody Mab 31-2. Stimulation of huma n glioblastoma cells both with alpha-thrombin and the thrombin recepto r activating peptide TRAP-C resulted in a series of [Ca+](i) spikes as shown by confocal laser fluorescence microscopy with fluo-3 as calciu m sensitive fluorescence indicator. This effect was completely blocked with the thrombin receptor antagonist peptide T1. Our results demonst rate functional thrombin receptors (PAR1) in primary cultures of human glioblastomas for the first time.