Massive cell vacuolization induced by organic amines such as procainamide.
Procaine and some other basic drugs reportedly induce vacuolization of various cell types. We addressed the concentration-effect and structure-activity relationships as well as the mechanism of this effect using three cell lines. Massive vacuolization occurs over several hours in primary cultures of rabbit pulmonary artery smooth muscle cells (SMCs) and COS-1 cells in response to procaine and loosely related amine compounds (procainamide, N-acetyl-procainamide, metoclopramide, lidocaine, triethylamine, nicotine) used at 2.5 mM. Furthermore, chloroquine, propranolol, diphenhydramine, and neutral red are active in this respect at 100 to 250 microM in SMCs and COS-1 cells. Human embryonic kidney 293 cells mildly responded to triethylamine, nicotine, and propranolol only. Tetraethylammonium was uniformly inactive, as well as many other drugs in all three cell types (concentrations up to 2.5 mM). Procainamide does not induce apoptosis in SMCs treated for up to 48 h, although the vacuolization is sustained and proliferation and migration are reduced during this period. Procainamide-induced vacuolization is reversible on drug washing, largely prevented by bafilomycin A1 cotreatment, and has a tentatively identified Golgi origin (uptake of ceramide-C5). Procainamide and neutral red are concentrated in SMCs in a bafilomycin A1-sensitive manner. The preventive effect of bafilomycin A1 suggests that the vacuoles originate from the osmotic swelling of acidic organelles in which the charged basic drugs are trapped at low pH. Drug transport at the plasma membrane may be limiting for this type of response, as suggested by the cell type selectivity of agents and the inhibitory effect of some drugs such as quinidine.
Centre de recherche de L'Hôtel-Dieu, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada.
Guillaume
G
Morissette
Emmanuel
E
Moreau
René
R
C-Gaudreault
François
F
Marceau
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D019556:COS Cells; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009130:Muscle, Smooth / Q000166:cytology*; D011342:Procainamide / Q000494:pharmacology*; D011817:Rabbits; D013347:Subcellular Fractions; D013997:Time Factors; D014617:Vacuoles / Q000187:drug effects*
D000889:Anti-Arrhythmia Agents; D011342:Procainamide