RRC ID 61497
Author Sunayama J, Matsuda K, Sato A, Tachibana K, Suzuki K, Narita Y, Shibui S, Sakurada K, Kayama T, Tomiyama A, Kitanaka C.
Title Crosstalk between the PI3K/mTOR and MEK/ERK pathways involved in the maintenance of self-renewal and tumorigenicity of glioblastoma stem-like cells.
Journal Stem Cells
Abstract The molecular signaling pathways orchestrating the biology of cancer stem-like cells (CSLCs), including glioblastoma, remain to be elucidated. We investigated in this study the role of the MEK/extracellular signal-regulated kinase (ERK) pathway in the control of self-renewal and tumorigenicity of glioblastoma CSLCs, particularly in relation to the PI3K/mTOR (mammalian target of rapamycin) pathway. Targeted inactivation of MEK alone using pharmacological inhibitors or siRNAs resulted in reduced sphere formation of both cell line- and patient-derived glioblastoma CSLCs, accompanied by their differentiation into neuronal and glial lineages. Interestingly, this effect of MEK inactivation was apparently augmented in the presence of NVP-BEZ235, a dual inhibitor of PI3K and mTOR. As a potential explanation for this observed synergy, we found that inactivation of either the MEK/ERK or PI3K/mTOR pathway triggered activation of the other, suggesting that there may be mutually inhibitory crosstalk between these two pathways. Significantly, inactivation of either pathway led to the reduced activation of p70S6K, and siRNA-mediated knockdown of p70S6K resulted in the activation of both pathways, which no longer maintained the cross-inhibitory relationship. Finally, combinational blockade of both pathways in glioblastoma CSLCs suppressed their tumorigenicity, whether transplanted subcutaneously or intracranially, more efficiently than blockade of either alone. Our findings suggest that there is p70S6K-mediated, cross-inhibitory regulation between the MEK/ERK and PI3K/mTOR pathways, in which each contribute to the maintenance of the self-renewal and tumorigenic capacity of glioblastoma CSLCs. Thus, combinational disruption of these pathways would be a rational and effective strategy in the treatment of glioblastoma.
Volume 28(11)
Pages 1930-9
Published 2010-11-1
DOI 10.1002/stem.521
PMID 20857497
MeSH Aminoacetonitrile / analogs & derivatives Aminoacetonitrile / pharmacology Animals Butadienes / pharmacology Cell Differentiation / drug effects Cell Differentiation / genetics Cell Line, Tumor Enzyme Inhibitors / pharmacology Extracellular Signal-Regulated MAP Kinases / antagonists & inhibitors Extracellular Signal-Regulated MAP Kinases / metabolism* Glioblastoma / metabolism* Glioblastoma / pathology* Humans Imidazoles / pharmacology Male Mice Mice, Nude Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors Mitogen-Activated Protein Kinase Kinases / metabolism* Neoplastic Stem Cells / metabolism* Neoplastic Stem Cells / pathology Nitriles / pharmacology Phosphatidylinositol 3-Kinases / metabolism* Phosphoinositide-3 Kinase Inhibitors Quinolines / pharmacology Signal Transduction / drug effects Signal Transduction / genetics TOR Serine-Threonine Kinases / antagonists & inhibitors TOR Serine-Threonine Kinases / metabolism* Tumor Cells, Cultured
IF 6.022
Human and Animal Cells A172(RCB2530)