关键词: 口腔鳞状细胞癌, 长链非编码RNA, FLJ30679, 细胞增殖, 细胞迁移, 上皮-间充质转化

Abstract:

Background and purpose: Long noncoding RNA (lncRNA) can regulate gene transcription, mRNA shear, stabilization and translation, and it is an important regulatory factor in a variety of biological processes. This study aimed to investigate the expression and clinical features of lncRNA FLJ30679 in oral squamous cell carcinoma (OSCC) and its effect on the malignant biological behavior of OSCC. Methods: The expression of FLJ30679 in head and neck squamous cell carcinoma (HNSCC) tissues and normal tissues was analyzed by the UCSC Xena database for expression and prognosis. The expression of FLJ30679 in OSCC cell lines was detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). The subcellular localization of FLJ30679 in OSCC cells was detected by RNA nuclear-cytoplasmic fractionation assays. FLJ30679 Smart Silencer was used to establish the FLJ30679 knockdown group (SS-FLJ30679), and overexpression plasmid of FLJ30679 was used to establish FLJ30679 overexpression group (FLJ30679). The effects of altered FLJ30679 expression on the proliferative and migration capacity of OSCC cells were examined by cell counting kit-8 (CCK-8) and transwell migration assays. RTFQ-PCR and Western blot were used to determine the effect of altered FLJ30679 expression on the expression of epithelial-mesenchymal transition (EMT)-related genes in OSCC cells. The effects of altered FLJ30679 expression on the phosphoinositide 3-kinase (PI3K)/protein kinase (AKT) pathway were detected by Western blot. Results: Online query of database showed that FLJ30679 expression was higher in HNSCC tissues compared to normal tissues (P<0.01). HNSCC patients with higher FLJ30679 expression had lower overall survival (P<0.01). The RTFQ-PCR results showed that FLJ30679 was expressed at a higher level in six OSCC cell lines compared with normal cells, and was predominantly localized in the nucleus. The ability of OSCC cells in the SS-FLJ30679 group to proliferate and migrate was significantly lower compared with the SS-NC group (P<0.01). OSCC cells in the FLJ30679 overexpression group had significantly higher proliferative and migratory capacities than those in the vector group (P<0.001). RTFQ-PCR and Western blot results showed that FLJ30679 knockdown resulted in upregulation of mRNA and protein expression levels of E-cadherin (P<0.01) and downregulation of mRNA and protein expression levels of N-cadherin and vimentin (P<0.01). FLJ30679 overexpression resulted in downregulation of protein expression levels of E-cadherin (P<0.01) and upregulation of mRNA and protein expression levels of N-cadherin and vimentin (P<0.05). Western blot results showed that knockdown of FLJ30679 resulted in decreased protein expression levels of phosphorylated-PI3K (p-PI3K) and phosphorylated-AKT (p-AKT) (P<0.001), and overexpression of FLJ30679 resulted in increased protein expression levels of p-PI3K and p-AKT (P<0.01). Conclusion: The expression of FLJ30679 was increased in OSCC tissues and cells. It promoted the proliferation and migration ability of OSCC cells, which may be caused by FLJ30679 promoting EMT via PI3K/AKT pathway.

Key words: Oral squamous cell carcinoma, Long noncoding RNA, FLJ30679, Cell proliferation, Cell migration, Epithelial-mesenchymal transition