A molecular study of pathways involved in the inhibition of cell proliferation in neuroblastoma B65 cells by the GSK‐3 inhibitors lithium and SB‐415286

• Published in: Journal of cellular and molecular medicine 2009-09, Vol.13 (9b), p.3906-3917
• Main Authors: Pizarro, Javier G., Folch, Jaume, Esparza, José Luis, Jordan, J., Pallàs, Mercè, Camins, Antoni
• Format: Article
• Language: English
• Subjects: Aminophenols - pharmacology; Animals; Apoptosis; Apoptosis Inducing Factor - metabolism; B65 cells; cdc2; CDC2 Protein Kinase; Cell cycle; Cell Cycle - drug effects; Cell Cycle Proteins - biosynthesis; Cell Cycle Proteins - metabolism; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinases; Drugs; Effects; Enzyme Inhibitors - pharmacology; Glycogen Synthase Kinase 3 - antagonists & inhibitors; GSK3; Lithium; Lithium - pharmacology; Maleimides - pharmacology; Molecular Oncology; Molecules; Neuroblastoma - metabolism; Proteins; Rats; SB‐415286; Sirtuin 2 - biosynthesis
• ISSN: 1582-1838; 1582-4934
• DOI: 10.1111/j.1582-4934.2008.00389.x

Pharmacological GSK‐3 inhibitors are potential drugs for the treatment of neurodegenerative diseases, cancer and diabetes. We examined the antiproliferative effects of two GSK‐3 inhibitors, lithium and SB‐415286, on B65 neuroblastoma cell line. Treatment of B65 cells with either drug administered separately caused a decrease in cell proliferation that was associated with G2/M cell cycle arrest. Cell‐cycle proteins such as cyclins D, E, A, cdk4 and cdk2 were up‐regulated. Since lithium and SB‐415286‐induced G2/M arrest we studied changes in the expression of proteins involved in this phase, specifically cyclin B, cdc2 and the phosphorylated form of this protein (tyr15‐cdc2). Both drugs increased the expression of tyr15‐cdc2, thus inhibiting mitosis. On the other hand, SB‐415286 increased the expression of SIRT2, involved in the regulation of proliferation. Moreover, cell‐cycle arrest mediated by SB‐415286 was accompanied by apoptosis that was not prevented by 100 μM of zVAD‐fmk (benzyloxycarbonyl‐Val‐Ala‐Asp‐fluoromethylketone), a pan‐caspase inhibitor. Likewise, GSK‐3 inhibitors did not affect the mitochondrial release of apoptosis inducing factor (AIF). We conclude that inhibitors of GSK‐3 induced cell‐cycle arrest, mediated by the phosphorylation of cdc2 and, in the case of SB‐415286, SIRT2 expression, which induced apoptosis in a caspase‐independent manner.