文章摘要
缺氧通过SIRT1调控结直肠癌细胞自噬
Hypoxia promotes autophagy in colorectal cancer cells through SIRT1
投稿时间:2018-12-22  修订日期:2018-12-28
DOI:
中文关键词: 结直肠癌  缺氧  自噬  SIRT1
英文关键词: Colorectal cancer  Hypoxia  Autophagy  SIRT1
基金项目:肿瘤生物学国家重点实验室自主研究课题(CBSKL2017Z21),国家自然科学基金(No.81572545、No.81372783)
作者单位E-mail
余沈桐 空军军医大学基础医学院病理学教研室、肿瘤生物学国家重点实验室、西京医院病理科 陕西 西安 475095486@qq.com 
周汝 空军军医大学基础医学院病理学教研室、肿瘤生物学国家重点实验室、西京医院病理科 陕西 西安  
杨桐 空军军医大学基础医学院病理学教研室、肿瘤生物学国家重点实验室、西京医院病理科 陕西 西安  
崔竹青 空军军医大学基础医学院病理学教研室、肿瘤生物学国家重点实验室、西京医院病理科 陕西 西安  
张静 空军军医大学基础医学院病理学教研室、肿瘤生物学国家重点实验室、西京医院病理科 jzhang@fmmu.edu.cn 
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中文摘要:
      目的:探究缺氧调控结直肠癌细胞自噬的分子机制。方法:分别在常氧及缺氧(1%氧气浓度)条件下处理细胞,western blot检测细胞内沉默信息调节因子1(silencing information regulator 1,SIRT1)及自噬相关标志分子的表达情况;慢病毒转染构建SIRT1稳定过表达或敲减细胞株,利用透射电镜观察细胞内自噬体形成的情况;使用mRFP-GFP-LC3双标腺病毒感染细胞,在激光扫描共聚焦显微镜下观察细胞自噬流的进展。结果:缺氧条件下,SIRT1的表达水平随着缺氧时间的延长而降低,自噬特异性底物p62蛋白水平降低且LC3I/II转换增加;与对照组相比,SIRT1过表达能够抑制p62降解,而SIRT1敲减可促进p62降解;透射电镜结果发现SIRT1过表达后,细胞内自噬溶酶体形成减少、自噬体数量增多;SIRT1通过抑制自噬溶酶体的形成,阻断自噬流的进展。结论:缺氧通过抑制SIRT1的表达促进结直肠癌的细胞自噬。
英文摘要:
      Objective: To explore regulatory mechanisms of autophagy in colorectal cancer cells under hypoxia. Methods: Colorectal cells were exposed to normoxia and hypoxia (1% O2), respectively. Western blot analysis was used to detect the expressions of silencing information regulator 1 (SIRT1) and autophagy-related biomarkers. Lentivirus infection was used to obtained colorectal cells with stable SIRT1 overexpression or knockdown. Transmission electron microscope (TEM) was exploited to detect intracellular autophagosomes. After tumor cells were infected with adenovirus containing mRFP-GFP dual-labelled LC3, autophagy flux were detected under laser scanning confocal microscopy. Results: The expression of SIRT1 was decreased with the extension of hypoxic exposure time. Besides, autophagy specific substrate p62 was declined and the transition of LC3-I/II was enhanced. Compared with control group, the overexpression of SIRT1 inhibited the degradation of p62 while the downregulation of SIRT1 promoted the degradation of p62. The results from TEM observation indicated that the overexpression of SIRT1 decreased the number of autolysosomes while increased the number of autophagosomes. Moreover, SIRT1 inhibited the formation of autolysosomes and blocked the autophagy flux. Conclusion: Hypoxia promoted autophagy in colorectal cancer cells through inhibiting the expression of SIRT1.
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