STAT1对人肾透明细胞癌放射敏感性的影响

Effect of STAT1 on radiosensitivity of renal clear cell carcinoma

目的研究人肾透明细胞癌信号传递和转录活化因子1（STAT1）表达情况及抑制STAT1对该肿瘤细胞放射敏感性的影响。方法采用免疫组织化学染色技术对比检测34例人肾透明细胞癌标本和12例正常肾组织标本的STAT1表达。用Western blotting法检测离体培养人肾透明细胞癌细胞（CRL-1932）、纤维母细胞（CCL-116）和Wilm’s瘤细胞（CRL-1441）的STAT1表达。用氟达拉滨和siRNA抑制CRL-1932细胞STAT1表达，并通过成克隆法和台盼蓝染色计数法研究抑制STAT1对CRL-1932细胞放射敏感性的影响。结果人肾透明细胞癌标本的总STAT1和磷酸化STAT1表达均明显高于正常肾组织。Western blotting法显示CRL-1932细胞STAT1表达比CRL-1441、CCL-116细胞明显增高；药物氟达拉滨能显著抑制CRL-1932细胞磷酸化STAT1的表达，并显著增加CRL-1932细胞的放射敏感性，且放射增敏程度与药物浓度呈正相关。经STAT1 siRNA处理后CRL-1932细胞总STAT1和磷酸化STAT1的表达均被有效抑制，且细胞在照射后的存活分数显著下降。结论肾透明细胞癌STAT1呈高表达，抑制STATI对该细胞有放射增敏作用。

Objective To study the expression of signal transducer and activator of transcription 1 （STAT1） in human renal clear cell carcinoma （RCC） and the effect of STAT1 inhibition on the radiosensitivity of RCC. Methods The expression of STAT1 in 34 human RCC samples compared with 12 normal kidney tissues was examined by immunohistochemistry method. For in vitro experiments, a human RCC cell line, CRL-1932, was used. Western blotting was performed to evaluate the expression of total and phosporylated STAT1. Fludarabine and siRNA were respectively used to inhibit the expression of STAT1 in CRL-1932 ceils. Clonogenic assay and trypan blue staining assay were used to evaluate the radiosensitivity of CRL-1932 cells. Results The expression of both total and phosphorylated STAT1 in human RCC samples was significantly higher when compared to normal kidney tissues. Similarly, the expression of STAT1 was higher in CRL-1932 cells when compared to fibroblast and Wilm＇s tumor cell lines. STAT1 expression was inhibited by both fludarabine and siRNA. Radiosensitivity of CRL-1932 cells was enhanced by both fludarabine and siRNA induced STAT1 inhibition. Conclusions STAT1 is over-expressed in both human RCC tissue and cell line. Inhibition of STAT1 can enhance the radiosensitivity of RCC cells.