转录因子激活蛋白-4在结直肠癌中的表达及与细胞凋亡的相关性

Expression of activator protein-4 in colorectal carcinoma and its relationship with apoptosis

目的观察转录因子激活蛋白（AP）-4在正常直肠、腺瘤和结直肠癌组织中的表达，探讨其表达与临床病理、转移相关基因血管内皮生长因子（VEGF）和基质金属蛋白酶（MMP）-9的表达、细胞凋亡间的关系。方法利用组织芯片和免疫组织化学技术，检测正常直肠、腺瘤组织标本各16例及结直肠癌80例中AP-4蛋白的表达，采用逆转录-聚合酶链反应（RT—PCR）方法检测各组VEGF、MMP-9mRNA的转录水平，以缺口末端标记技术（TUNEL）检测结直肠癌细胞的凋亡指数。结果（1）正常直肠组织、直肠良性腺瘤、结直肠癌组织AP-4的阳性表达率分别为12．50％（2／16），25．00％（4／16），56．25％（45／80），其中良性直肠组织18．75％（6／32），良性直肠组织AP-4的阳性表达率与结直肠癌组织比较，两者差异有显著的统计学意义（X^2=12．96，P〈0．01）；结直肠癌患者不同年龄、性别、肿瘤部位、大小、血清CEA水平、组织学类型的AP-4表达程度比较，差异无统计学意义（P〉0．05）；不同分化程度、病理分期、淋巴转移、5年生存率的AP-4表达程度比较，差异有统计学意义（P〈0．05）；（2）结直肠癌组织VEGF和MMP-9转录水平显著高于正常直肠组织和腺瘤（P〈0．05），结直肠癌组织AP-4结合活性增强与VEGF和MMP-9高表达显著相关（P〈0．01）；（3）结直肠癌AP-4基因表达程度不同的结直肠癌细胞凋亡指数（AI）间的差异有统计学意义（F=58．76，P〈0．01）。结论AP-4基因表达升高可能与结直肠癌的发生密切相关，AP-4可能参与了结直肠癌的发生、发展和侵袭转移。

Objective To investigate the expression of activator protein-4 （AP-4） in normal rectal tissue, clorectal adenoma and colorectal carcinoma and its relationship with the clinical pathology, the metastasis -associated gene （VEGF,MMP-9） expression and apoptosis. Methods Tissue microarray and immunohistochemistry SP were used to detect the expression of AP-4 protein in 16 cases of the normal rec- tal tissue, 16 cases of rectal adenoma and 80 cases of the colorectal carcinoma. The mRNA expression levels of VEGF and MMP-9 were measured by RT-PCR. TUNEL was used to examine the apoptosis index （AI） in 80 cases of the colorectal carcinoma. Results （ 1 ） The positive rate of AP-4 gene expression in adenocarcinoma was 56.25% （45/80） ,which was significantly higher than in benign lesion of rectal tissue [ 18.75 % （ 6/32）, P 〈 0.01 ]. There was no significant relationship between the AP-4 gene expression and histological grades, the gender as well as the age （P 〉 0.05 ）, but there was a significant relationship between AP-4 gene expression and lymph node metastasis, differentiation, Dukes system as well as the 5- year survival rate after operation; （2） The transcription levels of VEGF and MMP-9 in colorectal carcino- ma were significantly higher than those in normal rectal tissue and rectal adenoma tissues （ P 〈 0.05 ）. The transcription levels of VEGF and MMP-9 were significantly correlated with the increased AP-4 DNA binding activity; （3） The mean AI in AP-4 negative tumors was significantly lower than that in AP-4 positive tumors （P 〈 0.01 ）. Conclusion AP-4 gene may play a role in the oncogenesis, progression and metastasis of colorectal carcinoma. The abnormal regulation of apoptosis may play an important role in the pathogenesis of colorectal carcinoma.