Lack of Inhibition of BBN-induced Bladder Carcinogenesis in C57BL/6 Mice by Intravesical Instillation of KRN 7000.

Abstract

The immunostimulatory α-galactosylceramide, KRN 7000 or (2S, 3S, 4R)-1-0-(α-D-galactopyranosyl)-2-(N-hexacosnoylamino)-1,3,4-octadecatrienol, might be anticipated to have antitumor activity in vivo apart from any direct toxicity to cancer cells. We investigated inhibition of mouse bladder carcinogenesis by intravesically instillated KRN 7000. C57BL/6 mice were divided into 4 groups; all first receiving the carcinogen 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine in drinking water for 8 weeks. Next, groups 1 and 2, respectively were administered 10 and 0.1 μg/kg of KRN 7000 intravesically once weekly for 17 weeks. Group 3 received only 0.3 ml of saline (vehicle control). Group 4 did not undergo bladder catheterization. By histologic examination at 26 weeks, the incidence of bladder carcinoma of all types tended to be higher in group 1 than in group 3, but without significance. The incidence of bladder carcinoma in group 4, (no catheterization), was similar to that in group 1. Only one precancerous lesion (papillary or nodular dysplasia) was seen in each of groups 3 and 4. Thus vesical instillation of KRN 7000 did not inhibit bladder carcinogenesis in mice, exposed to the carcinogen studied.