The antiapoptotic effect of (-) deprenyl on human phaeochromocytoma cells after serum deprivation has been reported by earlier. Two melanoma (M-1 and HT-2058) cell lines were used in our experiments. Serum deprivation for five days resulted in excessive number of apoptosis in the cell cultures. Very low doses of (-)-deprenyl (10-7 - 10-13 mol) caused an approximately 2 days delay in the onset of apoptosis. At the same time, +deprenyl was ineffective. In further experiments (-)-deprenyl and (-)desmethyl-deprenyl was administered in higher doses (10-2, 10-3 and 10-4 mol) to A-2058 melanoma and HT-1080 fibrosarcoma cells in culture. In these experiments no serum deprivation was applied and the treatment was started 24 hours after plating. Total eradication of the A-2058 cells was caused by 10-2 mol (-)-deprenyl and (-)-desmethyl-deprenyl. The type of cell death appeared to be apoptosis. Sixty percent apoptotic ratio was seen 24 hours and 72 hours after 10-3 mol (-)-desmethyl-deprenyl treteatment. The same dose of (-)-deprenyl caused 50% apoptosis an 72h. Only (-)-desmethyl-deprenyl induced apoptosis (20%) at 24 hours, in the dose of 10-4 mol. Interestingly (-)-deprenyl treatment resulted in 60% apoptosis 48 hours and in 20% apoptosis. Seventy-two hours after the administration of this compound, in case of HT-1080 fibrosarcoma cells. Sixty per cent apoptosis was found in the culture of the same cell, type 72 hours after treatment with (-)-desmethyl-deprenyl. (-)-desmethyl-deprenyl, in the dose of 10-2, eradicated this cell culture by apoptosis. On the other hand, 10-2 mol (-)-deprenyl caused socalled cytoplasmic, vacuolar, non-lysosomal active cell death (Clarke type III) 24, 48 hours after (-)-deprenyl administration. In vivo treatment of A-2058 melanoma xenografts (growing in immunodeprived mice) with 0.2-2-20 mg/kg daily subcutaneous dose of (-)-desmethyl-deprenyl resulted in dose-dependent growth inhibition of this tumor. Our results show that - deprenyl and its metabolite may influence apoptosis and other type of active cell death dose dependently. The role of caspases in this phenomenon should be investigated. (-)-deprenyl (Selegilin) a known MAO-B inhibitor is used in the therapy of Parkinsonism, Alzheimer's disease and other neurodegenerative dysorders (1). The neuroprotective and neuronal rescue effect of this compound cannot be explained by the MAO-B inhibitory action of this substance. In vitro studies on cultured cells of neuronal origin pointed to the fact, that (-)-deprenyl prevents the apoptosis-inducing effect of serum deprivation and other damaging agents in such a low dose which does not exhibit MAO-B inhibitory effect (2). The antiapoptotic action of (-)-deprenyl has been first described on human phaeochromocytoma cells (3) and confirmed among others on human melanoma cells by our group (4). At the same time (+)deprenyl and a metabolite of (-)deprenyl, (-)-desmethyl-deprenyl proved to be ineffective in our experiments. As the antiapoptotic effect of (-)-deprenyl is dose-dependent in a paradox way - i.e. very low doses (10-7 - 10-9 - 10-12 mol) are more effective than higher doses (10-5 - 10-3 mol), the question emerged whether higher doses of (-)-deprenyl as well as (-)-desmethyl-deprenyl inhibit or enhance apoptosis in cell cultures.
|Number of pages||7|
|Publication status||Published - Dec 1 2000|
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