Cystathionine Promotes the Proliferation of Human Astrocytoma U373 Cells

Background/Aim: In certain cancers, accumulation of cystathionine has been observed. The present study investigated the effect of cystathionine on astrocytoma (U373) cell proliferation, the activity of gamma-cystathionase (CTH) and changes in thiols levels. Materials and Methods: The methods used in the study included cytotoxicity assay, crystal violet staining method, CTH activity assay and reverse phase-high performance liquid chromatography (RP-HPLC). Results: The addition of cystathionine to the culture medium resulted in an increase of cystathionine level in U373 cells after 24 h of culture. Reduction of intracellular cystathionine level after 48 and 72 h of culture was associated with increased L-cysteine and L-cystine levels and stimulation of cell proliferation. Interestingly, a decrease in intracellular L-cysteine and L-cystine levels during the first hours of culture was observed. Conclusion: Elevated levels of cystathionine resulted in increased U373 cell proliferation by increasing the L-cysteine levels and GSH/GSSG ratio (especially after 72 h of the culture), but not with a simultaneous increase in the levels of total glutathione.