LINC01551 promotes metastasis of nasopharyngeal carcinoma through targeting microRNA-132-5p

M.-Y. Xue, H.-X. Cao

Department of Otorhinolaryngology-Head & Neck Surgery, Affiliated Hospital of Jiangnan University (The Fourth People’s Hospital of Wuxi), Wuxi, China. yzchx@vip.163.com

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• Oncology

OBJECTIVE: Previous studies have shown that long intergenic non-coding RNA01551 (LINC01551) is a cancer-promoting gene. However, the role of LINC01551 in nasopharyngeal carcinoma (NPC) has not been reported. Therefore, the aim of this study was to investigate the expression characteristics of LINC01551 in NPC, and to further explore its mechanism in promoting the metastasis.

PATIENTS AND METHODS: Quantitative real time-polymerase chain reaction (qRT-PCR) was used to detect the expression levels of LINC01551 in tumor tissue samples and paracancerous normal ones of 36 patients with NPC; meanwhile, the expression of LINC01551 in NPC cell lines was also verified using the qRT-PCR assay. In addition, the LINC01551 knockdown model was constructed in NPC cell lines (CNE2 and 6-10B) using lentivirus, and the influence of LINC01551 on the function of NPC cells was analyzed by cell counting kit-8 (CCK-8) and transwell invasion assays. Finally, the interaction between LINC01551 and microRNA-132-5p was examined by Luciferase reporter gene assay, while the potential mechanism was further explored by cell reverse experiments.

RESULTS: The results of qRT-PCR indicated that the expression level of LINC01551 in tumor tissue specimens of these patients was remarkably higher than that in adjacent tissues, and the difference was statistically significant. Meanwhile, LINC01551 expression was also found remarkably higher in cell lines than that in normal ones. In addition, compared with blank or control group, the proliferation, invasion and metastasis ability of NPC cells in LINC01551 knockdown group (si-LINC01551) was significantly reduced. Subsequently, the result of Luciferase reporting assay demonstrated that overexpression of microRNA-132-5p attenuated the Luciferase activity of the wild-type LINC01551 vector without attenuating that of the mutant vector, further demonstrating that LINC01551 can be combined with miR-132-5p. Additionally, the result of cell reverse experiment revealed that knockdown of microRNA-132-5p could reverse the effect of LINC01551 silencing on proliferation rate and metastasis of NPC cells, thus further demonstrating the mutual regulation between LINC01551 and microRNA-132-5p.

CONCLUSIONS: The above studies indicated that LINC01551 was remarkably up-regulated in NPC tissues, as well as in cell lines. In addition, studies have shown that LINC01551 may promote the metastatic ability by regulating microRNA-132-5p.

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