| Summary: | 碩士 === 國立中山大學 === 生物醫學研究所 === 102 === MicroRNAs (miRNAs) are a class of small endogenous single-stranded non-protein coding RNAs, about 21-24 nucleotides in length. Dysfunctional miRNAs play important role during oral squamous cell carcinoma (OSCC) progression, and contribute to modulate cell proliferation, apoptosis, migration, invasion and cell cycle by silencing protein-coding genes. However, the detailed mechanisms and biological functions of miRNAs in OSCC have yet to be fully elucidated. In this study, we performed the expression profile of human small RNAs in OSCC tissues and the corresponding adjacent normal tissues of two OSCC patients by Next generation sequencing approach. According to the profiles, we identified 45 miRNAs were significantly upregulated (fold change > 2) and 17 miRNAs downregulated (fold change < 0.5) in OSCC, respectively. Among them, the expression levels of miR-196b were further evaluated in 69 paired OSCC tissue samples using the stem-loop real-time polymerase chain reaction. Our results showed that miR-196b significantly overexpressed in OSCC tissues, as compared to the corresponding adjacent normal tissue samples (64 out of 69; 92.7%, p < 0.001). Analysis of the methylation status indicated the frequent hypomethylation of the CpG islands upstream of miR-196b in OSCC tissues compared with adjacent normal tissues (32 out of 69; 46.3 %), and the methylation status correlated inversely with miR-196b expression levels. Furthermore, the methylation status of miR-196b promoter was correlated with the poor disease-specific survival of OSCC patients (p = 0.035). Functional analysis showed that miR-196b could facilitate migration and invasion in OSCC cell lines, suppression of miR-196b by transfection with anti-miR-196b abrogated in vitro migration and invasion in OSCC cell lines. Together, our findings indicate that miR-196b plays a crucial oncogenic role in promoting cell migration and invasion during OSCC progression and thus may serve as a potential prognosis marker or therapeutic target for OSCC.
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