Abstract: OBJECTIVE: In order to identify the effect and mechanism of miRNAs involved in carcinogenesis， we evaluated the miRNA expression profiles at different stages of HBE cell transformation. METHODS：HBE，HBER and HBERST cells were collected and cultured. The comparison of differential expression profiles among these three cells was performed and analyzed by miRNA microarray. Then，the differentially expressed miRNAs were selected for validation by semi-quantitative real-time PCR. Finally，the functions of these miRNAs were examined using cell growth cure，cell cycle analysis and colony formation assay. RESULTS：856 human miRNAs were tested with microarray analysis in HBE，HBER and HBERST cell lines. Six differentially expressed miRNAs were found in HBERST compared with HBE and HBER cell lines，including 4 down-regulated and 2 up-regulated miRNAs. Among these miRNAs，miR-27a was found to be upregulated by SV40 ST in HBE cells. Suppression of miR-27a expression in HBERST cells inhibited the rate of cell growth (P＜0.01) and led to cell cycle arrested in the G0-G1 phase (P＜0.01). In addition，suppression of miR-27a in HBERST cells attenuated the capacity of cell colony formation (P＜0.01). CONCLUSION：Promotion of cell growth by miR-27a overexpression might be responsible for the viral oncoprotein small T antigen-induced malignant transformation.

Key words: Simian virus 40, small T antigen, HBE cells, miRNA