The expression of microRNA let-7 in esophageal squamous cell carcinoma and its clinicopathological significance

Abstract

Objective To estimate the effect of microRNA (miRNA) let-7 expression on human esophageal squamous cell carcinoma(ESCC) and the relationship between let-7 level and clinicopathological parameters. Methods ESCC cell line (Eca109) was transfected with let-7 or its inhibitor by RNAi and cell transfection techniques. Normal cultured Eca109 cell was served as negative control. The proliferation of Eca109 cell was detected by MTT. The expression of let-7 in Eca109 cells and 45 paired ESCC tissues and corresponding para-cancerous tissues were measured using real-time quantitative polymerase chain reaction (qRT-PCR). The relationship between let-7 level and clinicopathological parameters in patients with ESCC was analyzed. Results The A value of let-7 in Eca109 cells transfected with let-7 was lower than negative control (P=0.005), while it was higher in Eca109 cells transfected inhibitor than that in negative control 72 hours after transfection. In comparison with negative control, the expression of let-7 in Eca109 cells transfected with let-7 was increased 33% (1.33 vs 1.00,P=0. 039) and it was decreased 50% in Eca109 cells transfected with inhibitor (0.50 vs 1.00,P=0. 014). The ratio of let-7 expression in ESCC tissue and para-cancerous tissue was 0.66 ± 0.47 with significant differece (P= 0.001). Moreover, The level of let-7 expression in Han patients with ESCC was lower than Kazakh patients with ESCC (0.48±0.43 vs 0. 88±0.51,P=0. 019). The level of let-7 expression in poorly differentiated ESCC tissue was lower than well differentiated ESCC tissue (0.42±0.30 vs 0.84±0.38,P=0. 015). The level of let-7 expression in patients with lymph node metastasis was lower than those without lymph node metastasis (0.50±0.35vs 0. 80±0.52,P=0. 032) . Conclusion It is demonstrated that let-7 can inhibit the carcinogenesis and development of ESCC. The level of let-7 expression is associated with cell differentiation,lymph node metastasis and nationalities. Key words: Esophageal neoplasms; Carcinoma, squamous cell; RNA, small nuclear; transfection; RNA interference