MLKL contributes to shikonin-induced glioma cell necroptosis via promotion of chromatinolysis. (28th December 2019)

• Record Type: Journal Article
• Authors: Ding, Ye; He, Chuan; Lu, Shan; Wang, Xuanzhong; Wang, Chongcheng; Wang, Lei; Zhang, Ji; Piao, Meihua; Chi, Guangfan; Luo, Yinan; Sai, Ke; Ge, Pengfei
• Is Part Of: Cancer letters. Volume 467(2019)
• Page Start: 58
• Page End: 71
• Publication Date: 2019-12-28
• Subjects: MLKL -- Chromatinolysis -- Necroptosis -- Glioma -- Shikonin; Cancer -- Periodicals; Neoplasms -- Periodicals; Cancer -- Périodiques; Electronic journals; 616.994
• DOI: 10.1016/j.canlet.2019.09.007
• Languages: English
• ISSNs: 0304-3835

Abstract

Abstract: Chromatinolysis refers to enzymatic degradation of nuclear DNA and is regarded as one of the crucial events leading to cell death. Mixed-lineage kinase domain-like protein (MLKL) has been identified as a key executor of necroptosis, but it remains unclear whether MLKL contributes to necroptosis via regulation of chromatinolysis. In this study, we find that shikonin induces MLKL activation and chromatinolysis in glioma cells in vitro and in vivo, which are accompanied with nuclear translocation of AIF and γ-H2AX formation. In vitro studies reveal that inhibition of MLKL with its specific inhibitor NSA or knockdown of MLKL with siRNA abrogates shikonin-induced glioma cell necroptosis, as well as chromatinolysis. Mechanistically, activated MLKL targets mitochondria and triggers excessive generation of mitochondrial superoxide, which promotes AIF translocation into nucleus via causing mitochondrial depolarization and aggravates γ-H2AX formation via improving intracellular accumulation of ROS. Inhibition of nuclear level of AIF by knockdown of AIF with siRNA or mitigation of γ-H2AX formation by suppressing ROS with antioxidant NAC effectively prevents shikonin-induced chromatinolysis. Then, we found that RIP3 accounts for shikonin-induced activation of MLKL, and activated MLKL reversely up-regulates the protein level of CYLD and promotes the activation of RIP1 and RIP3. Taken together, our data suggest that MLKL contributes to shikonin-induced glioma cell necroptosis via promotion of chromatinolysis, and shikonin induces a positive feedback between MLKL and its upstream signals RIP1 and RIP3. Highlights: Shikonin activated MLKL and induced chromatinolysis in glioma cells in vitro and in vivo. MLKL promoted shikonin-induced chromatinolysis and necroptosis in glioma cells. Nuclear translocation of AIF and γ-H2AX contributed to shikonin-induced chromatinolysis. MLKL reinforced γ-H2AX formation via improvement of intracellular ROS. MLKL aggravated nuclear translocation of AIF via disturbing mitochondrial function.