目的：观察微小RNA-21（miR-21）对子宫内膜癌细胞PTEN基因的调控作用，并验证PTEN基因3'-UTR区内的微小RNA反应（MRE）-21片段为miR-21作用的靶向位点，为通过miR-21治疗子宫内膜癌提供依据。方法：在人子宫内膜癌HEC-1A细胞中转染不同浓度的miR-21拮抗剂、无关序列和空白对照，利用qRT-PCR法检测miR-21以及靶基因PTEN的mRNA水平，利用免疫印迹法检测PTEN的蛋白表达水平。再利用双荧光素酶报告基因法对miR-21与PTEN3'-UTR区内的MRE-21片段的靶向关系进行验证。结果：在HEC-1A细胞内，随着miR-21拮抗剂浓度的增加，miR-21的表达量逐步减少。miR-21拮抗剂组与无关序列组比较，miR-21表达量的减少差异有统计学意义（P<0.01）；PTEN蛋白表达量的增加差异亦有统计学意义（P<0.01）。pMER-报告载体和miR-21拮抗剂共转染HEC-1A细胞时，与pMIR-空白载体转染组以及pMER-报告载体转染组相比，荧光素酶表达水平皆显著上调（P<0.01）。结论：沉默miR-21能上调子宫内膜癌细胞内PTEN基因的表达，PTEN基因3'-UTR区的MRE-21片段为miR-21作用的靶向位点。

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