Role Of MicroRNA-21 And Regulation On PTEN In Esophageal Squamous Cell Carcinoma

Objective:To investigate the role of microRNA-21(miR-21) and its regulation on phosphatase and tensin homolog deleted from chromosome-10 (PTEN) protein expression in esophageal squamous cell carcinoma (ESCC).Methods:1. Specimens of ESCC and normal tissues were collected from ESCC patients, the mRNA expression of miR-21 and PTEN were detected by qRT-PCR method, and the prtotein expression of PTEN was examined by western blot technique. 2. MiR-21 mimics or its inhibitor was transfected into a human ESCC cell line Eca109. The mRNA expression of miR-21 and PTEN in the transfected cells were detected by qRT-PCR method, and the prtotein expression of PTEN were examined by western blot technique..Results:1.Compared with the corresponding control samples,the expression of miR-21 was significantly higher in the tumor samples(p<0.05), and significantly correlation with infiltration depth in ESCC(p<0.05). The protein expression of PTEN was significantly lower in the tumor samples compared with the corresponding control samples (p<0.05), however, mRNA expression of PTEN had no obvious significance between them. There was a significantly inverse correlation between miR-21 and PTEN protein levels(p<0.05). 2. In the Eca109 transfected with miR-21 mimics, the increased accumulation of miR-21 promoted cell proliferation, and resulted in decrease of PTEN protein levels with approximately 40%. However, the Eca109 transfected with miR-21 inhibitor, the decreased accumulation of miR-21 inhibited cell proliferation, and resulted in increase of PTEN protein levels with approximately 79%. Both of them had no effect on level of PTEN mRNA. Conclusion:1. MiR-21 and PTEN involved in ESCC carcinogenesis. 2. MiR-21 was overexpressed in ESCC tumor and promoted cell proliferation. As well as, there was positive correlation between the miR-21 overexpression and infiltration depth of the tumor; PTEN protein expression in ESCC was significantly lower than that in corresponding control samples and inverse correlation with the miR-21 expression. 3. In ESCC the miR-21 could down-regulate the protein expression PTEN in post-transcription level.