Comparison of a ceramidase inhibitor (ceranib-2) with C2 ceramide and cisplatin on cytotoxicity and apoptosis of glioma cells

Abstract

Inhibiting ceramidase activity in cancer cells has been identified as a promising target for cancer therapy in recent studies. Thus, we examined the possible role of ceranib-2, a novel ceramidase inhibitor, on growth and apoptotic mechanisms of the human normal glia cell line (HNA), human glioma cell lines (T-98G and U-87MG), and a rat glioma cell line (C6). We also compared the results with the effects of C2 ceramide and cisplatin. We determined the in vitro survival rate with MTT assay, apoptosis with flow cytometry, gene expressions with qRT-PCR, and statistical significance by one-way analysis of variance together with Tukey's test. Calculated from MTT outcomes, the inhibitory ranking was as follows: T-98G > U-87MG > C6 > HNA. Ceranib-2 had the most growth-suppressive activity on human T-98G cells with an IC50 of 7 mu M for 24 h and 0.9 mu M for 48 h. Only the 25 mu M dose of ceranib-2 induced apoptosis of human T-98G and U-87MG cells after 24 h of treatment; however, it increased apoptosis of C6 cells dose- and time-dependently. Ceranib-2 increased the cytochrome c gene expression level during 24 h in T-98G cells. Ceranib-2 had cytotoxic and apoptotic effects on glioma cells but the cytotoxic effect was weaker on normal glia cells. 'Ibis cytotoxicity was stronger than that of C2 ceramide and cisplatin.