Project description:RNF8 is downregulated in glioblastoma and low RNF8 expression correlates with poor patient prognosis. Overexpression (OE) of RNF8 in glioblastoma stem cell (GSC) impairs its proliferation and tumorigenicity, and the anti-cancer effects of RNF8 are dependent on both its FHA and RING domains. Paradoxically, transcriptomic analysis of RNF8 OE GSC reveals cell cycle as the top upregulated pathway. Mechanistically, RNF8 interacts with the mitotic checkpoint protein MAD2 in a RING domain-dependent manner to induce spindle assembly checkpoint (SAC) activation. RNF8 OE GSC displays increase level of aneuploidy and micronuclei formation, suggesting that RNF8 promotes chromosomal instability (CIN) in GSC through persistent SAC activation.
Project description:Glioblastoma is one of the most malignant brain tumors with poor prognosis and their development and progression are known to be driven by glioblastoma stem cells. Although glioblastoma stem cells lose their cancer stemness properties during cultivation in serum-containing medium, little is known about the molecular mechanisms regulating signaling alteration in relation to reduction of stemness. In order to elucidate the global phosphorylation-related signaling events, we performed a SILAC-based quantitative phosphoproteome analysis of serum-induced dynamics in glioblastoma stem cells established from the tumor tissues of the patient. Among a total of 2,876 phosphorylation sites on 1,584 proteins identified in our analysis, 732 phosphorylation sites on 419 proteins were regulated through the alteration of stem cell characteristics.