INHIBITION OF GROWTH AND REGRESSION OF A TRANSPLANTABLE RAT CHONDROSARCOMA BY 3 RETINOIDS

Abstract

An aromatic analog of retinoic acid, all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nonatetraenoic acid (Ro 10-1670), its ethyl ester (Ro 10-9359) and ethyl amide (Ro 11-1430) inhibited the growth of a transplantable rat chondrosarcoma. The inhibitions observed occurred over a range of tolerated doses. At the higher tolerated dose levels, significant regressions of already established tumors were observed. All 3 compounds were active when administered i.p. for 2 or 4 wk. The ethyl ester, Ro 10-9359, and the ethyl amide, Ro 11-1430, were also active when administered for 4 wk as dietary admixes. In the latter experiments, both compounds were equally effective at tolerated doses, but Ro 11-1430 was less toxic than Ro 10-9359 at higher doses.