ABSTRACT
Retinoids are capable of inhibiting the proliferation of murine S91-C2 melanoma cells and stimulating morphological and biochemical differentiation in vitro. This chapter describes the effect of Retinoic acid (RA) and numerous synthetic analogs of vitamin A and related compounds on the growth of the S91-C2 melanoma cells in culture. The potency of 13-cis-RA in inhibiting melanoma cell growth is equivalent to that of RA, however the efficacy of ring-modified 13-cis-RA analogs such as the 5,6-epoxy and 2,3,6-trimethyl-4-methoxyphenyl ring was lower than the efficacy of the same analogs of RA. The finding of very specific structural requirements for activity of retinoids on the S91-C2 melanoma cells implies that the cells possess a mechanism for distinguishing active from inactive compounds. The S91-C2 melanoma cell system is useful for screening new retinoids for biological activity because results obtained with these cells compare favorably with other systems.
