Downregulation of microRNA 99a in oral squamous cell carcinomas contributes to the growth and survival of oral cancer cells

Yan,Bin; Fu,Qihong; Lai,Lihua; Tao,Xinran; Fei,Yanghonghong; Shen,Jiangen; Chen,Zuodong; Wang,Qingqing

doi:10.3892/mmr.2012.971

Downregulation of microRNA 99a in oral squamous cell carcinomas contributes to the growth and survival of oral cancer cells

Authors:
- Bin Yan
- Qihong Fu
- Lihua Lai
- Xinran Tao
- Yanghonghong Fei
- Jiangen Shen
- Zuodong Chen
- Qingqing Wang
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Affiliations: Department of Oral and Maxillofacial Surgery, Ningbo First Hospital, Ningbo 315000, P.R. China, Department of Stomatology, Hangzhou Normal University Clinical Medicine College, Hangzhou 310036, P.R. China , Institute of Immunology, Zhejiang University School of Medicine, Hangzhou 310058, P.R. China
Published online on: June 27, 2012 https://doi.org/10.3892/mmr.2012.971
Pages: 675-681

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Abstract

microRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression by either translational inhibition or mRNA degradation. miRNAs play pivotal roles in physiological functioning and pathological progression. The function of microRNA-99a (miR-99a) in oral squamous cell carcinoma (OSCC) remains unclear. In the present study, we investigated the roles of miR-99a in OSCC development and the underlying mechanisms in 25 cases of primary OSCC tissues and Tca-8113 cells. The cells were analyzed using FACS analysis and western blotting. Results showed that the expression levels of miR-99a were markedly decreased in OSCC tissues compared with the adjacent non-tumor tissues (n=25). The results of in vitro experiments showed that miR-99a mimics significantly inhibited the proliferation of Tca-8113 cells, a tongue squamous carcinoma cell line, and that miR-99a mimics markedly induced the apoptosis of Tca-8113 cells. Furthermore, we demonstrated that mammalian target of rapamycin (mTOR) was directly targeted by miR-99a, as the overexpression of miR-99a in Tca-8113 cells downregulated the protein expression level of mTOR. Thus, our findings suggest that the downregulation of miR-99a in OSCC tissues is associated with tumor development. miR-99a regulates the growth and survival of OSCC cells and may be exploited as a biomarker and therapeutic target for patients with OSCC.

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