S100A4:潜在抑制膀胱癌干细胞的靶分子

目的 应用siRNA技术沉默S100A4基因表达对膀胱癌干细胞增殖及成瘤能力的影响.方法 筛选鉴定出MB49膀胱癌干细胞后,应用核素标记相对和绝对定量(iTRAQ)技术,发现MB49膀胱癌细胞与膀胱癌干细胞表达差异的蛋白质S100A4蛋白.设计并合成S100A4基因特异性的siRNA序列,转染膀胱癌干细胞,应用Western blot和qPCR检测在siRNA对S100A4的影响,体内、外实验观察siRNA抑制S100A4后对膀胱癌干细胞增殖及成瘤能力的影响.结果 通过iTRAQ核素标记结合液相色谱和串联质谱分析,共鉴定出差异蛋白共65个,S100A4在基因表达水平差异最显著(差异为5.70,P<0.05).与空白对照组、阴性对照组相比,S100A4 siRNA转染组的S100A4基因和蛋白表达降低(P<0.05).CCK8实验和裸鼠成瘤实验发现,与空白对照组与阴性对照组相比较,siRNA干扰S100A4表达后,膀胱癌干细胞生长明显受到抑制,成瘤能力受到抑制(P<0.05).结论 膀胱癌干细胞中S100A4表达与膀胱癌的复发、转移有关,S100A4蛋白可能成为消灭膀胱癌干细胞,治疗膀胱癌的分子靶标.

S100A4, a potential therapeutic target on bladder cancer stem cells

Objective To observe the effect of S100A4 gene silencing mediated by small interfering RNA (siRNA) on the proliferation of bladder cancer stem cells (CSCs) and their capacity of xenograft tumor formation. Methods MB49 bladder cancer stem cells (MCSCs) were isolated and identified. The differentially expressed protein S100A4 was identified in MCSCs using isobaric tags for relative and absolute quantitation technology (iTRAQ). A siRNA targeting S100A4 was constructed and transfected into MCSCs, and its inhibitory effects on S100A4 expression in MCSCs were assessed with Western blotting and qPCR. The effects of siRNA-mediated S100A4 silencing on the proliferation and xenograft tumor formation ability of MCSCs were observed. Results Among the 65 differentially expressed proteins identified by iTRAQ combined with LC/MS/MS, S100A4 protein showed the most distinct differential expression in MCSCs. Transfection of MCSCs with S100A siRNA significantly inhibited the expressions of S100A4 at both mRNA and protein levels, caused obvious suppression of the cell proliferation, and attenuated the xenograft tumor formation ability of the cells in nude mice. Conclusion S100A4 in MCSCs is associated with the recurrence and metastasis of bladder cancer. S100A4 may serve as a potential therapeutic target for eliminating bladder CSCs.