中文摘要：

目的探讨核转录因子2（N也）在人脑胶质瘤细胞系U251的细胞增殖与肿瘤生长过程中的调控作用机制。方法首先检测Nrt2在35例人脑胶质母细胞瘤与10例正常脑组织中的表达情况。通过构建质粒pEGFP．Nrf2和Si—Nrf2，进行细胞转染分别上调、下调U251中Nrt2的表达水平，并且筛选稳定转染细胞株。通过实时荧光定量PCR检测稳定转染细胞株Nrf2及其下游因子的转录水平，CCK．8检测其在体外增殖活性，再将其种植于裸鼠皮下观察其增殖情况，最后取种植瘤块进行免疫组化染色，检测Nrt2、Ki67、Caspase-3与CD31的表达。结果35例人胶质母细胞瘤中有29例表达Nrf2，阳性率为82．9％。上调Nrt2表达水平后，血红素氧化酶（HO）-1与醌氧化还原酶（NQO）-1转录水平上调，细胞增殖较快，移植瘤生长快，瘤块重（2．06±0．16）g，Ki67与CD31表达增加，Caspase-3表达较低。而下调Nrf2表达水平后，HO-1与NQO-1转录水平下降，细胞增殖较慢，移植瘤生长慢，瘤块重（0．29±0．03）g，Ki67与CD31表达较低，Caspase-3表达增加。结论Nrf2可能通过调控HO-1及NQO．1促进U251的增殖，并通过促进肿瘤细胞分裂、抑制肿瘤细胞凋亡、促进血管形成来促进胶质瘤的生长。

英文摘要：

Objective To investigate the role of nuclear factor erythroid 2-related factor （Nrf2）in cell proliferation of human glioblastoma muhiforme （GBM）. Methods Human GBM tissues was analysed to observe the protein level of Nrf2. Two kinds of plasmid, pEGFP-Nrf2 and Si-Nrf2, were constructed and transfected to upregnlate or downregulate the expression of Nrf2 in U251 cell line. Blank vectors or random siRNA plasmid were used as negative control. Cells treated with lipofectamine only were set up as blank control. Stable tranfected cells were established and mRNA levels of Nrf2 and downstream genes were detected. The proliferation rate among groups was measured in vitro and analyses were made on the xenograft tumors. Results Nrf2 was positively overexpressed in 82. 9% GBM tissues. With the Nrf2 levels being up- regulated, the mRNA levels of （hemeoxygenase, HO）-1 and[ NAD （P） H quinone oxidoreductase, NQO ]- 1 were greatly higher than group control and this improve cell proliferation and xenograft tumor growth. The knockdown of Nrf2 inhibited the mRNA expression of HO-1 and NQO-1, the cell proliferation in vitro and tumor growth. At last we performed the immunohistochemistry staining to detect the protein levels of Nrf2, Ki67, Caspase-3 and CD31 in the xenograft tumors, and found the protein levels of Nrf2 and Ki67 in group pEGFP-Nrf2 were much higher with lower Caspase-3 level compared with group control. Expression levels of Nrf2, Ki67 and Caspase-3 in group Si-Nrf2 were on the contrary. In the analysis of microvessel density （MVD） assessed by CD31, MVD value in group Si-Nrf2 decreased significantly while in group pEGFP-Nrf2 there was a significant increase. Conclusions These indicate that Nrf2 plays an important role in humanglioma U251 cell proliferation and tumor growth, which is probably related to HO-1 and NQO-1.