Fig. 7. An RAR-selective antagonist inhibits both RA- and DCS-induced lumen formation. (A) J3B1A cells suspended in collagen gels were either treated with RA alone (1 nM) or cotreated with RA and different concentrations of Ro 41-5253, a selective RAR antagonist. (B) J3B1A cells were suspended in collagen gels and incubated either with 0.1% DCS alone or with 0.1% DCS plus different concentrations of Ro 41-5252. Lumen formation was quantified after 6 days. ^*P<0.025 and ^**P<0.0005 compared with control values.