Specific protein interacting with a tumor promoter, debromoaplysiatoxin, in bovine serum is alpha 1-acid glycoprotein.
Aplysiatoxin and debromoaplysiatoxin, a debrominated form of aplysiatoxin, have both been shown to be potent tumor promoters in a two-stage carcinogenesis experiment on mouse skin. However, debromoaplysiatoxin did not behave like aplysiatoxin in most of the biological assay systems using cultured cells. The discrepancy was supposed to be due to a factor in the bovine serum used for culture, a similar factor not being present in sera of eight other animal species examined. The factor was purified to homogeneity from bovine serum by ammonium sulfate fractionation and chromatographies on DEAE-cellulose, Sephadex G-150, hydroxyapatite, and a reversed-phase HPLC column. The factor was a 40-kDa protein, and partial amino-acid sequencing of its tryptic peptides indicated that the factor is alpha 1-acid glycoprotein. Both the purified factor and the commercially available bovine alpha 1-acid glycoprotein abolished in vitro the activation of protein kinase C by debromoaplysiatoxin but not that by aplysiatoxin. Debromoaplysiatoxin induced differentiation of HL-60 cells into macrophages at a comparable concentration to aplysiatoxin, when serum-free medium was used. These results suggest that alpha 1-acid glycoprotein, which interacts specifically with debromoaplysiatoxin, contained in bovine serum must have masked the in vitro properties of the tumor promoter in the biological assay systems.
Ueyama
H
H
Department of Medical Biochemistry, Shiga University of Medical Science, Otsu, Japan.
Sasaki
I
I
Shimomura
K
K
Suganuma
M
M
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D016588:Anticarcinogenic Agents / Q000302:isolation & purification* / Q000494:pharmacology; D002273:Carcinogens / Q000633:toxicity*; D002417:Cattle; D004347:Drug Interactions; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008235:Lyngbya Toxins / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009961:Orosomucoid / Q000302:isolation & purification / Q000494:pharmacology* / Q000502:physiology; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D012680:Sensitivity and Specificity; D017386:Sequence Homology, Amino Acid; D014316:Tritium
D016588:Anticarcinogenic Agents; D002273:Carcinogens; D008235:Lyngbya Toxins; D009961:Orosomucoid; D014316:Tritium; D015240:Phorbol 12,13-Dibutyrate; C017179:debromoaplysiatoxin; D004815:Epidermal Growth Factor; D011493:Protein Kinase C