EFFECTS OF PRODIGIOSIN 25-C ON CULTURED-CELL LINES - ITS SIMILARITY TO MONOVALENT POLYETHER IONOPHORES AND VACUOLAR TYPE H+-ATPASE INHIBITORS

Prodigiosin 25-C inhibited the proliferation of various cultured cell lines more strongly when concanavalin A (Con A) was added to the cultures. The increase in sensitivity was most evident in T lymphoma YAC-1 cells. The combination of prodigiosin 25-C and Con A induced characteristic morphological changes in these cells. In the presence of Con A, monovalent polyether ionophores and vacuolar type H+-ATPase inhibitors induced effects similar to those of prodigiosin 25-C on YAC-1 cells. Prodigiosin 25-C had neither K+ionophore activity nor inhibitory effect on vacuolar type H+-ATPase. A Golgi mannosidase II inhibitor, swainsonine, inhibited the proliferation of YAC-1 cells only when Con A was added. Prodigiosin 25-C and swainsonine increased Con A binding receptors on the surface of YAC-1 cells. These results suggest that prodigiosin 25-C affects the intracellular transport and/or processing of glycoproteins.