[Show abstract][Hide abstract] ABSTRACT: Glioblastoma (GBM) is the most lethal type of primary brain tumor with florid angiogenesis. GBMs display striking cellular hierarchies containing self-renewing glioma stem cells (GSCs) that are highly tumorigenic. GSCs not only produce elevated levels of VEGF to promote tumor angiogenesis but also contribute to cellular compartments of tumor vessels.
[Show abstract][Hide abstract] ABSTRACT: Glioblastomas are highly lethal brain tumors containing tumor-propagating glioma stem cells (GSCs). The molecular mechanisms underlying the maintenance of the GSC phenotype are not fully defined. Here we demonstrate that the zinc finger and X-linked transcription factor (ZFX) maintains GSC self-renewal and tumorigenic potential by up-regulating c-Myc expression. ZFX is differentially expressed in GSCs relative to non-stem glioma cells and neural progenitor cells (NPCs). Disrupting ZFX by shRNA reduced c-Myc expression and potently inhibited GSC self-renewal and tumor growth. Ectopic expression of c-Myc to its endogenous level rescued the effects caused by ZFX disruption, supporting that ZFX controls GSC properties through c-Myc. Furthermore, ZFX binds to a specific sequence (GGGCCCCG) on the human c-Myc promoter to up-regulate c-Myc expression. These data demonstrate that ZFX functions as a critical upstream regulator of c-Myc and plays essential roles in the maintenance of the GSC phenotype. This study also supports that c-Myc is a dominant driver linking self-renewal to malignancy. Stem Cells 2014
[Show abstract][Hide abstract] ABSTRACT: Glioblastoma multiforme (GBM) is the most lethal and aggressive type of primary brain malignancy. Failures of the traditional therapies in treating GBMs raise the urgent requirement to develop new approaches with more responsive targets. The phenomenon of the high infiltration of tumor-associated macrophages (TAMs) into GBMs has been observed for a long time. Regardless of the limited knowledge about TAMs, the high percentage of supportive TAM in GBM tumor mass makes it possible to be a good target for GBM treatment. In this review, we discussed the unique features of TAMs in GBMs, including their origin, the tumor-supportive properties, the secreted cytokines, and the relevant mechanisms. In addition, we tried to interpret the current understandings about the interplay between GBM cancer cells and TAMs. Finally, the translational studies of targeting TAMs were also described.
[Show abstract][Hide abstract] ABSTRACT: Glioblastomas (GBMs) are highly vascular and lethal brain tumors that display cellular hierarchies containing self-renewing tumorigenic glioma stem cells (GSCs). Because GSCs often reside in perivascular niches and may undergo mesenchymal differentiation, we interrogated GSC potential to generate vascular pericytes. Here, we show that GSCs give rise to pericytes to support vessel function and tumor growth. In vivo cell lineage tracing with constitutive and lineage-specific fluorescent reporters demonstrated that GSCs generate the majority of vascular pericytes. Selective elimination of GSC-derived pericytes disrupts the neovasculature and potently inhibits tumor growth. Analysis of human GBM specimens showed that most pericytes are derived from neoplastic cells. GSCs are recruited toward endothelial cells via the SDF-1/CXCR4 axis and are induced to become pericytes predominantly by transforming growth factor β. Thus, GSCs contribute to vascular pericytes that may actively remodel perivascular niches. Therapeutic targeting of GSC-derived pericytes may effectively block tumor progression and improve antiangiogenic therapy.