肿瘤抑制因子C53抑制肿瘤血管再生作用的研究

Research on the anti-angiogenic activity of tumor suppressor C53

目的模拟肿瘤中的低氧状态,研究人类脐静脉内皮细胞(HUVEC)中C53水平的变化及其在血管再生中的调控作用。方法采用2%O2浓度低氧培养HUVEC作为实验组,且依据低氧培养时间段不同分为4组:12 h组、24 h组、36 h组及48 h组,常氧培养HUVEC组作为对照组,共计5组。分别收集各组细胞样本,检测胞内C53、p38MAPK、phos-p38MAPK等多种蛋白水平。分别收集各组细胞培养上清液,检测其中血管内皮生长因子(VEGF)水平。采用5组不同的细胞培养上清液培养HUVEC,分别检测各组HUVEC的增殖率、迁移率及管腔形成能力。结果与常氧对照组相比,低氧培养36 h及48 h组HUVEC中C53蛋白水平降低,而p38MAPK活化水平增高。与常氧对照组相比,低氧培养12、24、36及48 h组HUVEC的VEGF分泌水平均高于常氧对照组(P﹤0.05)。同常氧培养上清液相比较,低氧培养上清液可提高内皮细胞血管再生能力的增殖、迁移及管腔形成能力,尤以36 h和48 h组表现更为明显(P﹤0.05)。结论肿瘤中的低氧微环境可抑制C53蛋白的表达,通过减轻C53对p38MAPK通路的抑制作用,有效激活p38MAPK通路及下游的效应分子VEGF的合成及表达,达到促进血管再生目的。

Objective To study the anti-angiogenic activity of C53 and its molecular mechanisms in human umbilical vein endothelial cells （HUVEC） under artificial tumor-like hypoxic environment. Method The HUVEC in study group were treated hypoxically at 2%O2 （for 12 hours, 24 hours, 36 hours, and 48 hours, respectively）, while the control group was given normoxic treatment. After treatment, the HUVEC and the culture supernatant of all groups were collected re-spectively for detection of cellular C53, p38MAPK, phos-p38MAPK proteins and secreted VEGF. HUVEC from the 5 groups were cultured in collected supernatant respectively to observe the angiogenetic ability of cells. Result Compared with the control group, HUVEC after hypoxic treatment of 36 h and 48 h presented less C53 along with higher level of p38MAPK phosphorylation. Hypoxic treatments of 12 h, 24 h, 36 h and 48h could markedly promote secretion of VEGF in HUVEC （P〈0.05）. In contrast to the supernatant from control group, supernatant collected from hypoxic treatment groups significantly promoted the proliferation, migration and tube formation ability of HUVEC, especially after treat-ment for 36 h and 48 h （P〈0.05）. Conclusion Hypoxic microenvironment in tumor may inhibit C53, simultaneously alle-viating inhibition of p38MAPK pathway to enhance VEGF secretion and angiogenesis.