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2143821 
Journal Article 
Correlation of cocarcinogenic activity among n-alkanes with their physical effects on phospholipid micelles 
Horton, AW; Eshleman, DN; Schuff, AR; Perman, WH 
1976 
Yes 
Journal of the National Cancer Institute
ISSN: 0027-8874
EISSN: 1460-2105 
HEEP/76/08364 
56 
2 
387-391 
English 
815559 
WOS:A1976BH07800030 
HEEP COPYRIGHT: BIOL ABS. N-alkanes from C12-C28 were tested for their cocarcinogenic or promoting activities in mice to evaluate a correlation of their biologic activity with their effects on transport properties of phospholipid micelles. On this basis, C18 and C20 homologs were more active than the better known dodecane. The C12, C16, C18 and C20 n-alkanes, at various dilutions from 6-40% by volume in decahydronaphthalene (Decalin), were tested for their relative activity in a cocarcinogenic relationship to benzo(a)pyrene. At a 20% alkane concentration level, the solutions containing octadecane and eicosane induced tumors most rapidly. A 40% dodecane concentration was required to produce this level of cocarcinogenic activity. The activity of octadecane paralleled its physical effects on transport kinetics closely in the 6-40% (by volume) concentration. The C18, C20 and C28 n-alkanes and the C30 olefin squalene at dilutions from 10-40% in Decalin (by volume) were tested for their relative promoting activity after a single application of 7,12-dimethyl-benz(a)anthracene in benzene. At comparable mole fractions in Decalin, the 3 n-alkanes had essentially the same promoting activity. Squalene, at 20%, showed only borderline activity. The high biologic activity of the C18, C20 and C28 n-alkanes correlated well with their physical effects on structure of phospholipid micelles (chain-chain interactions of the alkanes with the acyl chains of the lipid). This correlation was interpreted as a stong indication that the liquid crystalline region of the phospholipid assembly (adjacent to the aqueous interface) in the membranes of latent (initiated) cancer cells was the site of action of hydrocarbon cocarcinogens. Application of a modified physical model to pristane, a branched-chain C19 alkane from coal and Colorado (USA) shale, indicated higher cocarcinogenic activity than that of n-C18H38. Applied to purified samples of docosane and tetracosane, activity comparable to that of octadecane was indicated. 
Alkanes; Benzopyrenes; Micelles; Phospholipids; 9,10-Dimethyl-1,2-benzanthracene; 57-97-6; Index Medicus; Animals; Neoplasms, Experimental -- chemically induced; Structure-Activity Relationship; Alkanes -- pharmacology; Skin Neoplasms -- chemically induced