Cytotoxicity mediated by conditional expression of a carboxyl-terminal derivative of the beta-amyloid precursor protein.
The beta amyloid peptide which accumulates within the brains of patients with Alzheimer's disease (AD) is proteolytically derived from a precursor protein (beta PP). We established and characterized four stably transformed human neuroblastoma cell lines which conditionally expressed a partial beta PP fusion protein (amino-17 residues+carboxyl-99 residues; S beta C). Conditional expression of S beta C was achieved using a tetracycline-responsive promoter system. Expression of this fusion protein in one of the cell lines resulted in pronounced cytotoxicity. Addition of n6,O2'-dibutyryl adenosine 3',5'-cyclic monophosphate and/or fetal bovine serum to the culture medium of this cell line further elevated the level of S beta C expression and enhanced the associated cytotoxicity. Conditioned medium, acquired from cells expressing S beta C, was not cytotoxic. These findings suggest that modulation of beta PP expression and/or metabolism can have cytotoxic consequences. This is the first report of cytotoxic effects mediated by conditional expression of a beta PP derivative. This immortal cell line provides a unique opportunity to screen for complementary DNAs which suppress this toxicity. Such cDNAs could help elucidate the processes underlying S beta C mediated cytotoxicity which in turn could further our understanding of the pathogenesis of AD and could also provide additional candidate genes for various forms of familial AD.
Sopher
B L
BL
Department of Pathology, University of Washington, Seattle 98195.
Fukuchi
K
K
Smith
A C
AC
Leppig
K A
KA
Furlong
C E
CE
Martin
G M
GM
D000544:Alzheimer Disease / Q000378:metabolism; D016564:Amyloid beta-Protein Precursor / Q000096:biosynthesis*; D001921:Brain / Q000378:metabolism; D003994:Bucladesine / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D009447:Neuroblastoma; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D013752:Tetracycline / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured
D016564:Amyloid beta-Protein Precursor; D011993:Recombinant Fusion Proteins; D003994:Bucladesine; D013752:Tetracycline