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.
Department of Pathology, University of Washington, Seattle 98195.
B L
BL
Sopher
K
K
Fukuchi
A C
AC
Smith
K A
KA
Leppig
C E
CE
Furlong
G M
GM
Martin
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