Cytotoxic and cytoskeletal effects of azaspiracid-1 on mammalian cell lines.
Azaspiracid-1 (AZA-1) is a newly identified phycotoxin reported to accumulate in molluscs from several northern European countries and documented to have caused severe human intoxications. The mechanism of action of AZA-1 is unknown. Our initial investigations have shown that AZA-1 is cytotoxic to a range of cell types. Cytotoxicity was evident in all seven cell types tested, suggesting a broad-spectrum mode of action, and was both time- and concentration-dependent. However, AZA-1 took an unusually long time (>24 h) to cause complete cytotoxicity in most cell types, with the exception of the rat pituitary GH(4)C(1). Extended exposure times did not always lower the EC(50) value for a given cell line, but always resulted in more complete cytotoxicity over a very narrow concentration range. The Jurkat cell line (human lymphocyte T) appeared to be very sensitive to AZA-1, although the EC(50) values (24-72 h) for all the cell types were in the low nanomolar range (0.9-16.8 nM). The effect of AZA-1 on membrane integrity was tested on Jurkat cells and these data confirm our visual observations of cytotoxicity and necrotic cell lysis following exposure of Jurkat cells to AZA-1 and suggest that AZA-1 has some properties unique among marine algal toxins. Additionally, there were dramatic effects of AZA-1 on the arrangement of F-actin with the concurrent loss of pseudopodia, cytoplasmic extensions that function in mobility and chemotaxis. Although these phycotoxin-specific effects of AZA-1 suggest a possible site of action, further work using cell-based approaches is needed to determine the precise mode of action of AZA-1.
Twiner
Michael J
MJ
Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, NOAA/National Ocean Service, Charleston SC 29412, USA.
Hess
Philipp
P
Dechraoui
Marie-Yasmine Bottein
MY
McMahon
Terry
T
Samons
Melissa S
MS
Satake
Masayuki
M
Yasumoto
Takeshi
T
Ramsdell
John S
JS
Doucette
Gregory J
GJ
D000199:Actins / Q000378:metabolism; D000818:Animals; D049872:Bivalvia / Q000737:chemistry; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D003599:Cytoskeleton / Q000187:drug effects / Q000473:pathology; D006801:Humans; D019169:Jurkat Cells; D008387:Marine Toxins / Q000633:toxicity*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011554:Pseudopodia / Q000187:drug effects* / Q000473:pathology; D013141:Spiro Compounds / Q000633:toxicity*; D000095702:Polyether Toxins
D000199:Actins; D008387:Marine Toxins; D010749:Phosphoprotein Phosphatases; D013141:Spiro Compounds; C406592:azaspiracid; D000095702:Polyether Toxins