NMDA AND HIV-1 COAT PROTEIN, GP120, PRODUCE NECROTIC BUT NOT APOPTOTIC CELL-DEATH IN HUMAN CHP100 NEUROBLASTOMA CULTURES VIA A MECHANISM INVOLVING CALPAIN

Treatment of neuroblastoma cultures with N-methyl-D-aspartate (NMDA) o r human immunodeficiency virus type 1 (HIV-1) coat protein, gp120, ind uces significant cytotoxic effects which are reduced by leupeptin, E-6 4, N-Ac-Leu-Leu-norleucinal (ALLnL) as well as by N-Ac-Leu-Leu-normeth ioninal (ALLnM) and this suggests that activation of the Ca2+-dependen t protease, calpain, is involved. The cell death induced by NMDA and g p120 appears to be of the necrotic type; in fact, analysis of DNA frag mentation by flow cytometry or agarose gel electrophoresis failed to d emonstrate signs of apoptosis, such as the presence of apoptotic bodie s or internucleosomal cleavage. Similar negative results were also obt ained by studying the nuclear morphology of the cells with Hoechst 332 58 staining. Altogether the data indicate that neuroblastoma cell deat h induced by NMDA and gp120 is of the necrotic type and this implicate s calpain protease. (C) 1996 Academic Press, Inc.