engleski

Lithium increases expression of p21WAF/Cip1 and survivin in human glioblastoma cells

Inroduction: Lithium is the most widely prescribed mood stabilizer, but the precise molecular mechanisms underlying its therapeutic function are not yet quite elucidated. Recent preclinical and clinical evidence indicate its neuroprotective and neurotrophic effects. As a tight coupling of function and metabolism in the central nervous system between glial cells and neurons has been recently detected, lithium effect on glial cells may participate also in total beneficial effects of this drug. The aim of the present study was to examine the molecular mechanisms induced in human glioblastoma A1235 cells by the treatment with lithium, especially its influence on the expression of apoptosis related genes. Second, cytotoxic effect of glutamate in glioblastoma cells was investigated, and the possible protective effect of lithium in this process evaluated. Materials & Methods: Cytotoxicity of lithium was examined by spectrophotometric MTT assay. To determine the distribution of cells in the cell cycle, flow cytometry was used. The expression of apoptosis related proteins (prokaspase 3, PARP, Bcl-2 and survivin) was examined by Western blot method. Results: Lower levels of lithium (0.5 mM and 2 mM) did not cause any cytotoxicity or changes in the cell cycle phase distribution following 72h incubation. However, higher dose (20 mM) was cytotoxic for glioblastoma cells, causing accumulation of cells in G2/M phase of the cell-cycle. The treatment with lithium did not alter the levels of Bcl-2, procaspase-3 and didn't cleave PARP, but increased the levels of p21WAF/Cip1 and survivin (also in therapeutic doses). Glutamate was cytotoxic only in concentration higher than 100 mM. It did not induce apoptosis, but suppressed survivin expression. Pretreatment with lithium (2mM) reverted change in survivin expression induced by glutamate. Conclusions: Increased expression of p21WAF/Cip (a protein with anti-apoptotic function), and survivin (a protein that supports the growth of cells by suppression of apoptosis and promoting cell proliferation), can be the early events in the long-term cell response to lithium, that may be involved in the beneficial effects of this drug. High levels of glutamate were toxic for human glioblastoma cells. For these doses the pretreatment with lithium reverted the supression of survivin expression caused by glutamate.

glioblastoma cells; glutamate; lithium; survivin; p21WAF/Cip1

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