Inhibition of Human Neuroblastoma Cell Proliferation by N-acetyl-L-cysteine as a Result of Increased Sulfane Sulfur Level.

Abstract

In various cancer cells, the level of sulfane sulfur-containing compounds is decreased compared to normal cells. In the present study the effect of N-acetyl-L-cysteine (NAC), which acts as a precursor of H2S synthesis, on the human neuroblastoma SH-SY5Y cell proliferation, the activity of 3-mercaptopyruvate sulfurtransferase (MPST), and the level of sulfane sulfur were investigated. SH-SY5Y cells were treated with NAC, while untreated cells were used as the control. The toxicity of NAC on the cells was studied by the LDH cytotoxicity assay; cell proliferation was examined by the MTT method. MPST activity and sulfane sulfur level were also analyzed in the NAC-treated cells. The addition of NAC to the medium, in non-cytotoxic concentrations, resulted in inhibition of the SH-SY5Y cell proliferation after 48 h of culture. The MPST activity and the level of sulfane sulfur-containing compounds were also elevated under the same culture conditions. The antiproliferative activity of NAC in the SH-SY5Y cells was associated with an increase in the MPST activity and consequently with an increase in the intracellular level of sulfane sulfur in these cells.