Effects of phospholipase Cγ on Polo-like kinase 1 expression in human glioma cells

Abstract.

Purpose: The precise regulation of the mammalian PLK-1 gene, involved in progression of the G2/M transition, remains to be clarified. Phospholipase Cγ, associated with cell proliferation and invasion in human gliomas, could be one of the important candidates for the modulation of PLK-1 expression. Therefore, we studied the correlation between PLCγ activity and PLK-1 expression and determined cell size and proliferation after PLCγ inhibition in two glioma cell lines and a primary culture of a glioblastoma. Methods: The glioma cells were investigated with highly specific chemical and antisense inhibition of PLCγ. The effects of the inhibition were checked by means of morphometrical, semiquantitative immunohistochemical methods, and MTT-assays. Results: The chemical and antisense inhibition of PLCγ resulted in decreased expression of PLK-1 and reduced cell density in glioma cell lines as well as in a primary culture of a glioblastoma. These findings were verified by MTT-assays. Conclusion: The activity of PLCγ seems to modulate the expression of PLK-1. In further experiments serum-depleted cultures, stimulated by different growth factors, should be used after inhibitor pretreatment to study the in vivo conditions.