Induction of Differentiation and Apoptosis, and Ley Antigen Expression by Treatment with 3,4-Dihydro-6-(4-(3,4-Dimethoxybenzoyl)-1-Piperazinyl)-2(1H)-Quinolinone (Vesnarinone) in a Human Salivary Cancer Cell Line.

Abstract

It has been found that 3, 4-dihydro-6-[4-(3, 4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinone (Vesnarinone), a newly synthesized positive inotropic agent, has differentiation-inducing activity against various human solid tumor cells.In the present study, we examined the effect of vesnarinone on the differentiation, apoptosis and Ley antigen expression of human adenoid squamous carcinoma-forming cell line TYS derived from a minor salivary gland, which was grown in culture. Cultivation of TYS cells in the presence of vesnarinone (10-50μg/ml) resulted in the formation of secretory granules with salivary amylase in the cytoplasm as well as in the induction of apoptosis in the cells detached from the plastic surface and floated in the medium, in which intracellular calcium levels were significantly increased. On the other hand, appearance of large cells with numerous vacuoles having salivary amylase was observed in the attached cells, in which apoptotic change was not detected. Ley expression was detected in the cytoplasmic membrane of cultured TYS cells, while translocation of Ley antigen from cytoplasmic membrane to perinuclear area was observed in the attached TYS cells treated with vesnarinone. Moreover, it has been found by immunoblot analysis of TYS cell membrane proteins and cytosolic proteins that the Ley antigen in TYS cells forms a complex with 40kd protein and the Ley complex moves from cytoplasmic membrane to perinuclear area in the attached TYS cells undergoing acinar cell differentiation, but not apoptosis. Thus, it can be considered that the translocation of Ley antigen in vesnarinone-treated TYS cells may be associated with the cellular differentiation, rather than with the induction of apoptosis.