CAMP and acute monocytic leukemia: The authors compared the VDR-dependent CYP24A1 and cathelicidin antimicrobial peptide (CAMP) transcriptional activities of the 24-oxo analogue (149), its metabolic precursor 136, and the natural hormone, 1α,25(OH)2D3 (2), using peripheral blood mononuclear cells (PBMCs) as well as human acute monocytic leukemia cells (THP-1 cells), and revealed that both 16-ene analogues (136,149) exhibited similar transcriptional activities (EC50 ~0.7 nM) and greater activities than the natural hormone, 1α,25(OH)2D3 (2) (EC50 ~10 nM).