HUMAN ASTROCYTOMA-CELLS EXPRESS A UNIQUE CHLORIDE CURRENT

HUMAN astrocytoma cells were studied using whole-cell patch-clamp reco rding. Voltage-dependent outwardly-rectifying anion currents were iden tified in primary cultures of six freshly resected human brain tumors and in seven established anaplastic astrocytoma/glioblastoma cell line s (U251MG, CH235MG, U373MG, U105MG, D54MG, SK-MG-1, and STTG1). Anion currents were not observed in normal, non-neoplastic glial cells, nor in human tumor-derived cells of non-glial origin (melanoma, breast can cer, neuroblastoma, rhabdomyosarcoma). Currents activated at potential s >50 mV and showed large transients upon termination of voltage steps . Currents reversed at the predicted equilibrium potential for chlorid e ions and could also be recorded when Cl- was replaced by F-, Br- or I-. Currents were inhibited by the Cl- channel blockers chlorotoxin, D IDS, and DNDS. These Cl- currents may play a role in the growth contro l of astrocytoma cells.