靶向ST6Gal Ⅰ的siRNA与ASO联合应用对宫颈癌细胞转移能力的影响

目的 探讨人α2,6-唾液酸转移酶(ST6Gal Ⅰ)小分子干扰RNA(siRNA)及其与反义寡核苷酸(ASO)联合应用对ST6Gal Ⅰ高表达的宫颈癌HeLa细胞的粘附和侵袭力的影响.方法 设计并合成靶向ST6Gal Ⅰ的siRNA及ASO,用脂质体Lipofectamine 2000包裹后转染HeLa细胞.实验分为空白对照组、脂质体对照组、siRNA组、ASO1组(与siRNA相同靶点)、ASO2组(与siRNA不同靶点)、siRNA ASO1组及siRNA ASO2组,用RT-PCR测定细胞中ST6Gal Ⅰ mRNA水平,流式细胞仪检测细胞表面α2,6-唾液酸含量,分别用CytoMatrixTM细胞粘附试剂盒及细胞侵袭分析试剂盒,检测细胞对细胞外基质(ECM)的粘附与侵袭力.结果 转染后各实验组细胞的ST6Gal Ⅰ mRNA表达水平、细胞表面α2,6-唾液酸含量及细胞对ECM的粘附与侵袭力均低于空白对照组及脂质体对照组(P均＜0.05),以siRNA ASO2组调低作用最明显.其中siRNA组细胞的ST6Gal Ⅰ mRNA表达水平(0.55±0.08)、细胞表面α2,6-唾液酸含量(39.27±9.23)分别与siRNA ASO1组(0.54±0.09、38.27±7.74)比较,差异均无统计学意义,与siRNA ASO2组(0.33±0.09、9.10±0.40)比较,差异有统计学意义(P均＜0.05);siRNA组与siRNA ASO1组比较,细胞对ECM的粘附与侵袭力差异均无统计学意义,而siRNA ASO2组细胞对ECM的粘附与侵袭力较siRNA组降低(P均＜0.05).结论 化学合成的靶向ST6Gal Ⅰ的siRNA能够下调HeLa细胞中ST6Gal Ⅰ基因的表达,继而降低细胞对ECM的粘附和侵袭力,并且与不同靶点的ASO联合应用具有相加和协同效应.

Combinatorial Effects of ST6Gal Ⅰ siRNA and Antisense Oligonucleotide-mediated Gene Silence on Metastasis Ability of Cervical Carcinoma Cells

OBJECTIVE: To study the combinatorial effects of small interfering RNA (siRNA) and antisense oligonucleotides (ASOs) targeting alpha 2,6 sialyltransferase (ST6Gal I) on the cell adhesion and invasiveness of human cervical carcinoma cell line, HeLa with over-expressing ST6Gal I. METHODS: The siRNA and ASOs targeting to ST6Gal I were designed and synthesized chemically, and then with lipofectamine 2000, transferred into HeLa cells, which were cultured and divided into 7 groups: blank control group, liposome group, siRNA group transfected with ST6Gal I siRNA, ASO1 group transfected with ST6Gal I ASO whose target site is same as siRNA, ASO2 group transfected with ST6Gal I ASO whose target site is different with siRNA, siRNA+ASO1 group transfected with siRNA and its homologous ASO1, siRNA+ASO2 group transfected with siRNA and its nonhomologous ASO2. RT-PCR was used to examine the ST6Gal I mRNA expression. Flow cytometry was used to examine the amount of alpha2, 6-sialylation on the HeLa cell surface. The HeLa cell adhesion or invasiveness to extracellular matrix (ECM) was analyzed by using CytoMatrix kit or cell invasion assay kit, respectively. RESULTS: The expression of ST6Gal I mRNA, the amount of a2,6-sialylation of cell surface, the cell adhesion and invasion to ECM were remarkably decreased in siRNA group, ASO1 group, ASO2 group, siRNA+ASO, group and siRNA+ASO2 group, and all significantly lower than those in the blank control group and liposome group (all P < 0.05), especially in siRNA+ASO2 group. The difference was significant between siRNA+ASO2 group and siRNA group (all P < 0.05). No significant difference was observed between siRNA+ASO1 group and siRNA group, neither between blank control group and liposome group (all P > 0.05). CONCLUSION: The synthesized chemically specific siRNA targeting to ST6Gal I can effectively downregulate the ST6Gal I expression in HeLa cell and further lead to the decline of cell adhesion and invasiveness to ECM, and use of associating siRNA with ASO targeting to same gene but different oligonucleotide location possesses the synergy and additive effect on targeted gene expression knocked down.