Recombinant endostatin forms amyloid fibrils that bind and are cytotoxic to murine neuroblastoma cells in vitro

FEBS Letters

Voest, Emile E¹  Kranenburg, Onno¹  Wu, Ya-Ping²  Gebbink, Martijn F.B.G¹  Kroon-Batenburg, Loes M.J³  Reijerkerk, Arie¹ 

[1] Department of Medical Oncology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands;Department of Haematology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands;Department of Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands

关键词: Endostatin;    Amyloid;    Aβ;    IAPP;    Aggregation;    Cross-β;    Neuron;    Toxicity;    DMSO;    dimethylsulfoxide;    DMEM;    Dulbecco's modified Eagle's medium;    FITC;    fluorescein isothiocyanate;    PBS;    phosphate-buffered saline;    BSA;    bovine serum albumin;    Aβ;    amyloid beta;    hIAPP;    human islet amyloid polypeptide;    TEM;    transmission electron microscopy;   

DOI  :  10.1016/S0014-5793(03)00218-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Endostatin is a fragment of collagen XVIII that acts as an endogenous inhibitor of tumor angiogenesis and tumor growth. Anti-tumor effects have been described using both soluble and insoluble recombinant endostatin. However, differences in endostatin structure are likely to cause differences in bioactivity. In the present study we have investigated the structure and cellular effects of insoluble endostatin. We found that insoluble endostatin shows all the hallmarks of amyloid aggregates. Firstly, it binds Congo red and shows the characteristic apple-green birefringe when examined under polarized light. Secondly, electron microscopy shows that endostatin forms short unbranched fibrils. Thirdly, X-ray analysis shows the abundant presence of cross-β sheets, the tertiary structure that underlies fibrillogenesis. None of these properties was observed when examining soluble endostatin. Soluble endostatin can be triggered to form cross-β sheets following denaturation, indicating that endostatin is a protein fragment with an inherent propensity to form amyloid deposits. Like β-amyloid, found in the brains of patients with Alzheimer's disease, amyloid endostatin binds to and is toxic to neuronal cells, whereas soluble endostatin has no effect on cell viability. Our results demonstrate a previously unrecognized functional difference between soluble and insoluble endostatin, only the latter acting as a cytotoxic amyloid substance.

【 授权许可】

Unknown