体内外观察DHA抑制结肠癌的作用及相关蛋白的表达

Inhibition of DHA on colorectal tumor pathogenesis and expression of related genes

目的:探讨二十二碳六烯酸(docosahexaenoic acid,DHA)在抑制结肠癌发生、发展中的分子机制,为DHA新型抗癌药物的应用提供理论基础。方法:首先,建立人结肠癌裸鼠动物模型,观察DHA对裸鼠结肠癌移植瘤生长的影响;其次,应用半定量逆转录酶聚合酶链反应方法,检测环氧合酶2(cyclooxygenase 2,COX2)、低氧诱导因子-1α(hypoxiainducible factor-1α,HIF-1α)、血管内皮细胞生长因子A(vascular endothelial growth factor-A,VEGF-A)、软骨寡聚基质蛋白(cartilage oligomeric matrix protein,COMP)、基质金属蛋白酶-1(matrix metalloproteinase-1,MMP-1)、基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)、固醇携带蛋白2(sterol carrier protein 2,SCP2)、多配体蛋白聚糖3(syndecan 3,SDC3)等多个与肿瘤发生发展密切相关基因的表达情况;最后,通过细胞水平实验对动物体内基因表达实验结果进行验证。结果:与对照组相比,DHA组裸鼠结肠癌移植瘤瘤块体积明显降低,证明DHA可以抑制结肠癌的发生发展;不管是在体内动物水平还是在体外细胞水平,DHA均可导致COX2、HIF-1α、VEGF-A、COMP、MMP-1、MMP-9、SCP2、SDC3基因表达水平明显降低。结论:DHA的抗癌作用涉及多方面、多层次的分子生物学机制。

Objective： To explore the underlying molecular mechanism of docosahexaenoic acid（DHA） inhibiting colorectal tumor pathogenesis, then to provide theoretical basis for application of DHA as a new anticarcinogen. Methods： A nude mice model with human colon cancer was conducted and effects of DHA feeding on growth of colorectal transplanted tumors in nude mice was observed. The expression of several genes correlated with tumorigenesis, including cyclooxygenase 2（COX2）, hypoxia-inducible factor-1α（HIF-1α）, vascular endothelial growth factor-A（VEGF-A）, cartilage oligomeric matrix protein（COMP）, matrix metalloproteinase-1（MMP-1）, matrix metalloproteinase-9（MMP-9）, sterol carrier protein 2（SCP2）, and syndecan 3（SDC3） were detected by semi-quantitative reverse transcriptase polymerase chain reaction in colorectal transplanted tumors of nude mice feeding with and without DHA. The influence of DHA on gene expression profiles in vivo was validated by in vitro experiment in HCT-16 cell line. Results： A significant decreased tumor size was observed in nude mice fed DHA. Both in vivo and in vitro results indicated that the expressions of these 8 target genes were significantly decreased by DHA treatment. Conclusion： It suggests that comprehensive and complicated mechanisms were involved in the antitumor functions of DHA.