[Correlations between miRNAs and TGF-β1 in tumor microenvironment of esophageal squamous cell cancer]

To detect the levels of mir-18a-5p, mir-23a-3p, mir-24-3p, mir-25-3p and TGF-β1 in tumor microenvironment of esophageal squamous cell cancer (ESCC) patients and explore their clinical significances and correlations.

The mRNA expressions of mir-18a-5p, mir-23a-3p, mir-24-3p, mir-25-3p and TGF-β1 were measured by real-time quantitative RT-PCR in ESCC cell lines ECA-109 and TE-1, normal esophageal squamous epithelial cells, tumor tissues and tumor-adjacent normal tissues from 52 ESCC patients. The expression of TGF-β1 protein in the three types of cells, tumor tissues and tumor-adjacent normal tissues from 52 ESCC patients was detected by Western blotting.

The expressions of mir-18a-5p, mir-24-3p, mir-25-3p and mir-23a-3p in ECA-109 were significantly higher than those in normal esophageal squamous epithelial cells (P<0.05); that is also true of the first three miRNAs in TE-1 (P<0.05). Compared with the normal esophageal squamous epithelial cells, the expression of TGF-β1 was reduced in ECA-109 and TE-1 (P<0.05). Compared with the normal tissues, ESCC tumor tissues were characterized by significant overexpressions of mir-18a-5p, mir-23a-3p, mir-24-3p and mir-25-3p with the rates being 86.5% (45/52), 63.5% (33/52), 78.8% (41/52), 86.5% (45/52), respectively (all P<0.05), and by significantly decreased expression of TGF-β1 (P<0.05). The up-regulation of mir-18a-5p, mir-23a-3p, mir-24-3p, mir-25-3p and the down-regulation of TGF-β1 were not correlated with sex, age, tumor size and tumor site in ESCC patients, but the overexpressions of mir-18a-5p, mir-23a-3p, mir-25-3p were significantly related to tumor differentiation (P<0.05), and a significant variation of mir-25-3p was found in different T stages (P<0.05). TGF-β1 level was lower in tumor tissues compared to normal tissues from the 52 ESCC patients, and higher in stage TIII/IV; than stage TI/II;(P<0.05), and a significant variation was found in histological differentiation (P<0.05). There was no correlation between mir-18a-5p, mir-23a-3p and TGF-β1, but mir-24-3p and mir-25-3p had an inverse correlation with TGF-β1 in tumor microenvironment of ESCC.

Mir-18a-5p, mir-23a-3p, mir-24-3p, mir-25-3p and TGF-β1 might play important roles in the carcinogenic process of ESCC.