Modification of growth and differentiation of myeloid leukemia cells by tumor promoters.

The tumor promoter TPA inhibited both functional and morphological differentiation of mouse myeloid leukemia M1 cells cultured in medium containing calf serum or horse serum, but enhanced these inductions in medium containing fetal calf serum. The metabolic processes of prostaglandin E2 synthesis were associated with modification by TPA of differentiation of M1 cells. The factor(s) in the sera affecting the differentiation of M1 cells with TPA was nondialyzable and macromolecular. Upon Sephadex G-200 gel filtration, much more inhibitory activity was found in calf serum than in fetal calf serum, and stimulatory activity was found only in fetal calf serum.