Synthesis and photochemical transformation of 3β,21-dihydroxypregna-5,7-dien-20-one to novel secosteroids that show anti-melanoma activity

▶ Synthesis of 3beta,21-dihydroxypregna-5,7-dien-20-one (21(OH) 7DHP). ▶ UVB-driven photoconversion to analogues of vitamin D, lumisterol (pL) and tachysterol. ▶ Detection and initial characterization of oxidated derivatives of 21(OH) 7DHP. ▶ 21(OH)7DHP and its derivatives stimulated translocation of vitamin D receptor into the nucleus and efficiently inhibited proliferation of melanoma cell lines. ▶ The EC50 values for 21(OH)pL and 21(OH)oxy-piT were 40-1300-fold lower for pigmented versus non-pigmented melanoma cells.