lncRNA RPSAP52 induced the development of tongue squamous cell carcinomas via miR‐423‐5p/MYBL2

Abstract Growing lncRNAs have been noted to involve in the initiation and development of several tumours including tongue squamous cell carcinomas (TSCCs). However, the biological role and mechanism of lncRNA RPSAP52 were not well‐explained. We indicated that RPSAP52 was higher in TSCC samples compared with that in control samples. The higher expression of RPSAP52 was positively correlated with higher T stage and TNM stage. Ectopic expression of RPSAP52 induced TSCC cell growth and cycle and induced cytokine secretion including IFN‐γ, IL‐1β and IL‐6, IL‐8, IL‐10 and TGF‐β. We found that the overexpression of RPSAP52 suppressed miR‐423‐5p expression in SCC‐4 cell. miR‐423‐5p was lower in TSCC samples compared with that in control samples, and miR‐423‐5p level was negatively correlated with higher T stage and TNM stage. Pearson's correlation indicated that miR‐423‐5p was negatively associated with that of RPSAP52 in TSCC tissues. Furthermore, MYBL2 was one direct gene of miR‐423‐5p and elevated expression of miR‐423‐5p suppressed MYBL2 expression and ectopic expression of RPSAP52 increased MYBL2 expression in SCC‐4 cell. Finally, we illustrated that RPSAP52 overexpression promoted TSCC cell growth and cycle and induced cytokine secretion including IFN‐γ, IL‐1β and IL‐6, IL‐8, IL‐10 and TGF‐β via modulating MYBL2. These data provided new insight into RPSAP52, which may be one potential treatment target for TSCC.


| Cell proliferation and ELISA
Different groups of TSCC cells were plated in 96-well plates. Cell growth was determined by CCK-8 method, and 10 μL CCK-8 reagent was added into each well until visual colour was changed.
The absorbance was determined by the microplate reader at 450 nM. Cytokine level was detected using ELISA reagents (R&D Systems). The absorbance at 450 nm was recorded by the microplate reader.

| Statistical analysis
The statistical assay was conducted by SPSS 21.0 software, and results were presented as mean ± SD. The difference between 2 groups was evaluated by t test, and P value < .05 was considered to be significant. The correlation between miR-423-5p and RPSAP52 was analysed by Pearson's correlation.

| RPSAP52 was overexpressed in TSCC samples
RT-qPCR data suggested that RPSAP52 was higher in TSCC samples compared with that in control samples ( Figure 1A). RPSAP52 was overexpressed in 25 TSCC cases (25/30, 83.3%) compared with control no-tumour samples ( Figure 1B). The higher expression of RPSAP52 was positively correlated with higher T stage ( Figure 1C) and TNM stage ( Figure 1D).

| D ISCUSS I ON
These data provided new insight into RPSAP52, which may be one potential treatment target for TSCC.

CO N FLI C T O F I NTE R E S T
There is no conflict of interest.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data will be made available after being required upon request from the corresponding author.