Effect of retinoic acid and phorbol-12-myristate-13-acetate on glycosyltransferase activities in normal and transformed cells.

Retinoic acid was found to increase the activity of cytidine monophosphosialic acid:lactosylceramide sialyltransferase activity in a nontransformed clonal hamster cell line, NIL 8, and a virally transformed clone, NIL 8-HSV. The potent tumor promoter phorbol-12-myristate-13-acetate (PMA) had no significant effect on sialyltransferase activity in NIL 8 cells but stimulated this activity almost 6-fold when added to NIL 8-HSV cells. There was a synergistically additive effect on sialyltransferase activity when PMA was added to NIL 8 cells in concert with retinoic acid.

Rapid morphological and substratum adherence response by hairy cell and other human leukemic cells to phorbol ester tumor promoters.

Human leukemic cells, maintained in tissue culture, responded differentially following exposure to the phorbol ester tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA). Short-term (0-2 h) TPA treatment of hairy cell leukemic cells (of presumed B-lymphocytic origin) resulted in the attachment of 5-100% of cells (depending on % leukemic mononuclear cells) to the culture dish and extension of long processes. Similar changes were also observed with cells from acute myelogenous, acute prolymphocytic and some acute monomyelocytic leukemic patients.

Phorbol ester tumor promoters specifically stimulate choline phospholipid metabolism in human leukemic cells.

Human hairy cell leukemia (HCL) cells in culture showed a marked increase in both [1-14C]acetate and [14C]choline incorporation into phosphatidylcholine (PC) when treated with a 10 nM concentration of 12-O-tetradecanoylphorbol 13-acetate (TPA) for 3 h. Dramatic morphological changes occurred and synthesis of most phospholipids was stimulated. However, the most dramatic increase was seen in the [14C]acetate labeling of both long- and short-chain fatty acid-containing sphingomyelins (from 200-425% of control levels), sphingomyelin being especially enriched in HCL cells.