Tumorigenicity Of Glioma Stem Cells Research Articles

FoxM1 and Wnt/β-Catenin Signaling in Glioma Stem Cells

Cancer stem cells may be responsible for tumor initiation and maintenance. The molecular mechanisms that control cancer stem cells are related to alterations in various signaling pathways, including the Wnt/β-catenin signaling pathway. The canonical Wnt/β-catenin signaling pathway is one of the major signaling systems in stem and progenitor cells, and aberrant activation of the Wnt/β-catenin signaling pathway is common in human cancers. As with β-catenin, FoxM1 has been found to play important roles in a number of cancers. In this review, we discuss the evidence that FoxM1 affects the expression and function of a variety of genes that are critical to the survival, proliferation, invasion, angiogenesis, and self-renewal of cancer stem cells. We highlight the pivotal roles of the Wnt/β-catenin and FoxM1 signaling pathways in neural stem and progenitor cells and glioma stem cells. We also discuss the evidence for cross-talk between the β-catenin and FoxM1 signaling pathways in the regulation of the stemness and tumorigenicity of glioma stem cells.

Dlxin-1, a member of MAGE family, inhibits cell proliferation, invasion and tumorigenicity of glioma stem cells

We have previously reported the presence of Dlxin-1, a member of the melanoma antigen gene (MAGE) family, in the brain and showed its function as a cell cycle arrest protein, suggesting that Dlxin-1 may have anti-proliferative functions in rapidly growing tumors. Using the cancer stem cell hypothesis, which attributes the initiation and progression of brain tumors to the cancer-initiating stem cells, we have investigated the role of Dlxin-1 in the glioma stem cells propagated by us as a cell culture system comprising of HNGC-2 cells. Our studies provide evidence about the role of Dlxin-1 as an anti-tumorigenic protein in the highly chemo-resistant glioma stem cells. Next, we show that these anti-proliferative effects are manifested by Dlxin-1 through down regulation of the activities of MMP-2 and MMP-9, and through interaction of Dlxin-1 with its target protein P311 that is involved in glioma cell invasion. In summary, we establish the roles for Dlxin-1, one as an anti-tumorigenic and anti-invasive protein in high-grade gliomas and the other as an inducer of differentiation of glioma stem cells. These two attributes, in conjunction, result in conversion of the drug-resistant brain tumor stem cells to the tumor-attenuated cells that may now be more amenable to effective therapeutic targeting.