X线辐射剂量对结直肠癌细胞microRNA-221和PTEN表达的影响

Effects of X-Ray Dose on Expressions of MicroRNA-221 and PTEN in Human Colorectal Carcinoma Cells

目的探讨不同剂量X线照射对人结直肠癌Caco2细胞系中microRNA-221(miR-221)和张力蛋白在10号染色体上同源缺失的磷酸酶(PTEN)表达的影响。方法常规培养Caco2细胞系并分为5组,分别给予不同剂量(0、2、4、6及8 Gy)的X射线照射,24 h后提取细胞总RNA和蛋白质,应用real-time RT-PCR方法检测Caco2细胞中miR-221和PTEN mRNA的表达水平,用Western-blot法检测PTEN蛋白的表达水平。结果 Caco2细胞系在不同剂量的X线照射下,其miR-221表达水平随着照射剂量的增加而增高,呈剂量依赖性(P<0.01);PTEN mRNA的表达水平无明显变化(P>0.05),但PTEN蛋白表达水平则随X线照射剂量的增加而逐渐降低,亦呈剂量依赖效应(P<0.01)。结论 X线照射剂量可影响结直肠癌Caco2细胞中miR-221和PTEN蛋白的表达。

Objective To investigate the effects of X-ray dose on the expressions of microRNA-221 （miR-221） and phosphatase and a tensin homolog deleted from chromosomel0 （PTEN） in human colorectal carcinoma （CRC） cells. Methods Human CRC-derived cell line, Caco2, was cultured conventionally. The cells were divided into five groups and exposed to different doses of X-ray （0, 2, 4, 6, and 8 Gy） respectively. The total RNA and protein of the Caco2 cells were extracted after irradiation, and the miR-221 and PTEN mRNA expressions were detected by real-time RT-PCR. Moreover, the protein alteration of PTEN in Caco2 cells was detected by Western-blot analysis. Results The radiation dose of X-ray significantly affected the expressions ofmiR-221 and PTEN protein in human Caco2 cells in a dose-dependent manner. Moreover, the miR-221 expression level was up-regulated gradually with the increase of irradiation dose, on the contrary, the PTEN protein expression level was down-regulated gradually （P〈 0.01）. Conclusion The radiation dose can affect the miR-221 and PTEN protein expression pattern in CRC cells.