The abilities of dihydrodiols and diol-epoxides of dibenz(a, h)anthracene, dibenz(a, c)anthracene, chrysene, 7-methylbenz(a)anthracene, and benzo(e)pyrene to initiate skin tumors in mice were determined by using a two-stage system of tumorigenesis. (±-trans-3,4-Dihydroxy-3,4-dihydro-7-methylenz(a)anthracene and (±-trans-1,2-dihydroxy-1,2-dihydrochrysene were found to be more active than their corresponding parent hydrocarbons when applied topically to Sencar mice, followed by twice-weekly applications of 12-O-tetra-decanoylphorbol-13-acetate. Although, (±)-trans-9,10-dihydroxy-9,10-dihydro-benzo(e)pyrene had more activity than benzo(e)pyrene, it was not significantly higher. (±-trans-3,4-Dihydroxy-3.4-dihydrodibenz(a,h)anthracene was found to have one-half of the tumor-initiating ability of dibenz(a, h)anthracene. (±-trans-3,4-Dihydroxy-3,4-dihydrochrysene and (±)-trans-10,11-dihydroxy-10,11-dihydrodibenz(a, c)anthracene were essentially inactive as skin tumor initiators. trans-9,10-Dihydroxy-anti-11,12-epoxy-9,10,11,12-tetrahydrobenz(e)pyrene, trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydrodibenz(a, h)anthracene, trans-10,11 -dihydroxy-anti-12,13-epoxy-10,11,12,13-tetrahydrodibenz(a, c)anthracene, and trans-3,4-dihydroxy-anti-1,2-epoxy-1,2,3,4-tetrahydro-7-methylbenz(a)anthracene were also found to be inactive as tumor initiators. trans-1,2-Dihydroxy-anti-3,4-epoxy-1,2,3,4-tetrahydrochrysene had 25% of the activity of chrysene. Results show that the dihydrodiols of 7-methylbenz(a)anthracene, dibenz(a, h)anthracene, and chrysene, which are the immediate metabolic precursors of bay-region diol-epoxides, have moderate to high initiating activity, whereas the dihydrodiol of benz(e)pyrene (an extremely weak initiator) has weak activity. The bay-region diol-epoxide of chrysene was the only diol-epoxide tested that had significant activity when compared to the corresponding parent hydrocarbon. Some of the dihydrodiol data provide further support for the bay-region theory of polycyclic hydrocarbon carcinogenesis.
|Original language||English (US)|
|Number of pages||4|
|State||Published - Jun 1 1980|
ASJC Scopus subject areas
- Cancer Research