Medical Imaging Department, Huai'an Second People's Hospital and The Affiliated Huaian Hospital of Xuzhou Medical University, Huai'an, China.
Department of Orthopedics, Lianshui County People's Hospital, Huai'an, China.
Life Sci. 2018 Sep 1;208:232-238. doi: 10.1016/j.lfs.2018.07.015. Epub 2018 Jul 10.
Osteosarcoma is one of the most aggressive types of primary bone cancer that responds poorly to radiotherapy frequently. The gene associated with retinoid-interferon mortality (GRIM-19) is a tumor suppressor that mediates cell apoptosis in multiple cancer types. However, the role of GRIM-19 in osteosarcoma and the underlying mechanism remain unclear. This study was designed to investigate the role and the underlying mechanism of GRIM-19 in osteosarcoma progression.
Osteosarcoma tissues and cell lines were utilized to analyze the expressions of GRIM-19 in osteosarcoma by qRT-PCR and Western blot. Methods containing flow cytometry, irradiation exposure, cells inoculation, plasmid transfection, and protein immunoprecipitation were used to investigate the underlying mechanisms of GRIM-19 in osteosarcoma progression.
GRIM-19 is downregulated in osteosarcoma tissues and cell lines. Exposure to radiation induces osteosarcoma cell apoptosis by upregulation of p53 both in U2OS (p53-wt) and exogenous p53-introduced MG-63 (p53-null) osteosarcoma cells. Overexpression of GRIM-19 accelerates radiation-induced osteosarcoma cells apoptosis by p53 stabilization ex vivo and in vivo. Mechanistically, forced expression of GRIM-19 diminishes the activity of E3 ubiquitin-protein ligase mouse double minute 2 homolog (MDM2), a specific p53 protease, results in the accumulation of p53 and activation of p53-mediated apoptosis.
GRIM-19 was proved to modulate radiation-induced osteosarcoma cells apoptosis in a p53 dependent manner by mediating MDM2 activity, which sheds light on the development of GRIM-19-based molecular target therapy on osteosarcoma.
骨肉瘤是一种最具侵袭性的原发性骨癌，对放疗的反应通常较差。与维甲酸-干扰素死亡率相关的基因（GRIM-19）是一种肿瘤抑制因子，可介导多种癌症类型的细胞凋亡。然而，GRIM-19 在骨肉瘤中的作用及其潜在机制尚不清楚。本研究旨在探讨 GRIM-19 在骨肉瘤进展中的作用及其潜在机制。
利用骨肉瘤组织和细胞系，通过 qRT-PCR 和 Western blot 分析骨肉瘤中 GRIM-19 的表达。采用流式细胞术、照射暴露、细胞接种、质粒转染和蛋白质免疫沉淀等方法，探讨 GRIM-19 在骨肉瘤进展中的潜在机制。
GRIM-19 在骨肉瘤组织和细胞系中下调。在 U2OS（p53-wt）和外源性 p53 引入的 MG-63（p53-null）骨肉瘤细胞中，辐射诱导 p53 上调，导致骨肉瘤细胞凋亡。GRIM-19 的过表达通过体外和体内 p53 稳定加速辐射诱导的骨肉瘤细胞凋亡。从机制上讲，强制表达 GRIM-19 可降低 E3 泛素蛋白连接酶小鼠双微体 2 同源物（MDM2）的活性，MDM2 是一种特异性 p53 蛋白酶，导致 p53 积累和激活 p53 介导的凋亡。
GRIM-19 通过调节 MDM2 活性，证明可调节辐射诱导的骨肉瘤细胞凋亡，这为基于 GRIM-19 的骨肉瘤分子靶向治疗的发展提供了依据。
