Particular Carcinogenic Activity of F-nor-Steranthrene

Abstract

SINCE the discovery of the polycyclic chemical structure of cholesterol on one hand, and, on the other, of the carcinogenicity of 3-methylcholanthrene, it has often been postulated that certain types of cancer might be due to some abnormality in the metabolism of cholesterol and bile acids, resulting in the formation in the body of one or several carcinogenic polycyclic hydrocarbons¹. Along these lines, Bergmann² pointed out the theoretical possibility for cholesterol (I) to be cyclized, with dehydration and dehydrogenation, into the hypothetical hexa-cyclic hydrocarbon (II), which he named ‘steranthrene’ (since, the word ‘steranthrene’ has been used to designate the non-methylated basic hydrocarbon). Although experimental evidence for the existence of such a biochemical transformation is still lacking, it was of great interest to examine hydrocarbons of the steranthrene group for carcinogenicity. One of these hydrocarbons, ‘angular’ steranthrene (III), was recently investigated in mice by Dannenberg³, and found to produce spindle-cell sarcomas by injection and epitheliomas by painting the skin; the substance showed approximately the same degree of activity as 3,4-benzopyrene and 3-methylcholanthrene. We report here the results of our experiments on another such hydrocarbon, F-nor-steranthrene (IV), the synthesis of which has recently been described⁴.