Objective:To investigated the expression and localization of the long non-coding RNA(lncRNA)STAG3L5P in oral squamous cell carcinoma(OSCC)cells and its effects on OSCC cell proliferation and migration.Methods:STAG3L5P expression in HNSC and OSCC was ana-lyzed online using gene expression profiling interactive analysis 2(GEPIA2)and the University of California Santa Cruz Xena(UCSC Xena)database,respectively.STAG3L5P expression in OSCC cell lines was detected using real-time fluorescence quantitative PCR(qPCR).Nuclear-cytoplasmic RNA fractionation assays were carried out to pinpoint the location of STAG3L5P.Cell counting kit-8(CCK-8)and Transwell migra-tion assays were used to assess OSCC cell proliferation and migration changes.The effect of STAG3L5P overexpression on epithelial-mesen-chymal transition(EMT)related gene expression was detected by qPCR and Western blot.The effect of STAG3L5P overexpression on PI3K/AKT pathway activity was also assessed by Western blot.Results:STAG3L5P was highly expressed in OSCC,and its expression correl-ated significantly with histological grade.STAG3L5P expression was significantly higher in OSCC cell lines than in normal cells.The level of cytoplasmic STAG3L5P in OSCC cells was significantly higher than that in the nucleus.The proliferation and migration capacity of OSCC cells overexpressing STAG3L5P were significantly enhanced compared to negative control OSCC cells.N-cadherin and vimentin mRNA and protein levels were significantly increased by STAG3L5P overexpression,while E-cadherin protein expression was decreased.Overexpression of STAG3L5P also increased activity of p-PI3K and p-AKT.Conclusions:STAG3L5P is up-regulated in OSCC,and STAG3L5P overexpression can promote OSCC cell proliferation and migration.This effect may be related to activation of the PI3K/AKT pathway,thus promoting EMT.

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.