1 alpha, 25-dihydroxycholecalciferol and human histiocytic lymphoma cell line (U-937): the presence of receptor and inhibition of proliferation.

Human histiocytic lymphoma cells (U-937) contain high affinity binding protein for 1 alpha, 25-dihydroxycholecalciferol. The Kd (0.2 nM) and sedimentation coefficient on sucrose gradients (3.7 S) are similar to those reported for 1 alpha, 25-dihydroxycholecalciferol receptor in other tissues. This secosteroid added to the culture was able to inhibit cell proliferation in a dose dependent manner. Differentiation-associated properties such as phagocytic ability, C3 rosette formation, positive reaction for alpha- naphtyl acetate esterase as well as electron microscopy examination indicate that 1 alpha, 25-dihydroxycholecalciferol induces in vitro monocyte-macrophage differentiation in this monoblast-like cell line.