Membrane effects of tumor promoters: Stimulation of sugar uptake in mammalian cell cultures

摘要: Phorbol esters stimulate 2-deoxy-D-glucose (DG) uptake in rodent and human cell cultures. The potent tumor promoting agent, 12-0-tetradecanoyl phorbol-13 acetate (TPA), induces a 12-fold stimulation confluent 3T3 cells 2.5-fold HeLa cells. When series of macrocyclic diterpenes are assayed, their relative potencies stimulating DG correlate with other known biologic effects these compounds. On molar basis, TPA is much more stimulator transport than insulin or epidermal growth factor. In cells, the ED50 value effect 0.2 nM. increase occurs immediately after addition TPA, reaches maximum at 90 minutes, persists for least three hours removal from medium, temperature dependent. not inhibited by cycloheximide actinomycin D. As control treated p-hydroxymercuribenzoate, phloridzin, cytochalasin B, dexamethasone. Although precise mechanism known, evidence presented that due to enhanced sugar rather intracellular metabolism. may be secondary generalized change membrane structure.