title: EGFR-AKT-Smad signaling promotes formation of glioma stem-like cells and tumor angiogenesis by ID3-driven cytokine induction.
abstract: Aberrant activation of receptor tyrosine kinases (RTK) is causally linked to the pathobiological traits of glioblastoma and genesis of glioma stem-like cells (GSC), but the underlying mechanism is still unknown. Here, we show that epidermal growth factor receptor (EGFR) signaling regulates the proliferation, angiogenesis, and acquisition of GSC characteristics by inducing inhibitor of differentiation 3 (ID3) and ID3-regulated cytokines [GRO1 and interleukins (IL)-6 and 8] induction. We found that EGFR-mediated ID3 expression was regulated by Smad5, which was directly phosphorylated by AKT. Furthermore, ID3 alone imparted GSC features to primary astrocytes derived from Ink4a/Arf-deficient mouse, and EGFR-ID3-IL-6 signaling axis gave rise to tumor cell heterogeneity. Conversely, EGFR inhibitors suppressed EGFR-AKT-Smad5-driven induction of ID3, which led to a decrease in the tumorsphere forming ability of GSCs and U87MG cells that possess an active mutant EGFR, EGFRvIII, without obvious cytotoxic effects. However, these cells seemed to regain colonogenic ability after removal of the EGFR inhibitors. Together, the results delineate a novel integrative molecular mechanism in which the RTK-ID signaling pathway governs genesis and maintenance of GBM histopathologic features, such as GSCs-based tumor initiation, progression, and angiogenesis.
authors: School of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea. jinx2354@korea.ac.kr
authors: Xun
authors: X
authors: Jin
authors: Jinlong
authors: J
authors: Yin
authors: Sung-Hak
authors: SH
authors: Kim
authors: Young-Woo
authors: YW
authors: Sohn
authors: Samuel
authors: S
authors: Beck
authors: Young Chang
authors: YC
authors: Lim
authors: Do-Hyun
authors: DH
authors: Nam
authors: Yun-Jaie
authors: YJ
authors: Choi
authors: Hyunggee
authors: H
authors: Kim
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis*; D066246:ErbB Receptors / Q000502:physiology*; D005910:Glioma / Q000473:pathology*; D006801:Humans; D051796:Inhibitor of Differentiation Proteins / Q000502:physiology*; D015850:Interleukin-6 / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000502:physiology*; D014411:Neoplastic Stem Cells / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000209:etiology*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D051785:Smad Proteins / Q000502:physiology*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D016207:Cytokines; D051796:Inhibitor of Differentiation Proteins; D015850:Interleukin-6; D009363:Neoplasm Proteins; D051785:Smad Proteins; C075640:ID3 protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt