CircRNA PCMTD1 Contributes To The Progression Of Oral Squamous Cell Carcinoma By Regulating The PI3k /AKT Signaling Pathway

Introduction: Oral squamous cell carcinoma(OSCC)is one of the most common and harmful malignant tumors in the head and neck region.There is a significant progress in the OSCC clinical treatment with the research increasing.However the 5-year survival rate of OSCC is only about 63% and mortality rate has not been improved significantly in recent years.The pathogenesis of OSCC remains unclear.In order to find potential therapeutic targets of OSCC,we study the effects of circular RNA PCMTD1(protein-L-isoaspartate O-methyltransferase domain containing 1)on proliferation,apoptosis,migration and invasion abilities of oral squamous cell carcinoma cell lines.Methods: 8 pairs of snap-frozen OSCC tissues and adjacent normal tissues were obtained to detect the circ RNAs expression of the OSCC tissues by high-throughput deep sequencing.45 pairs of snap-frozen OSCC tissues were selected to verify the significant circ RNAs by q RT-PCR.We further verified the circ RNA PCMTD1,then over-expression vector of circ RNA PCMTD1 was transfected to upregulate circ RNA PCMTD1 in the SCC-9,SCC-15,SCC-25 and Cal27 cell lines.Meanwhile,empty plasmid was transfected as negative control.The expression level of circ RNA PCMTD1 was detected to confirm the stable over-expression cell lines by q RT-PCR.5-Ethynyl-2'-deoxyuridine assay was carried out to estimate the cell proliferation with the effect of circ RNA PCMTD1.Circ RNA PCMTD1 effects were detected by transwell migration assay for cell migration and invasion.Cell cycle and apoptosis were detected by Flow Cytometry.The PI3K?AKT?BCL-2?BAX?Cyclin D1 protein level was detected by Western blotting analysis.Result: A total of 11942 circ RNA targets were detected by high-throughput deep sequencing in 8 pairs of samples and 51 differentially expressed circ RNAs were found through fold change filtering.The differentially expressed circ RNAs were validated out using q RT-PCR in 45 pairs of samples including the tissues for high-throughput deep sequencing.The results showed that circ RNA PCMTD1 was down-regulated in the OSCC tissues.The circ RNA PCMTD1 vector was constructed that could produce circ RNA PCMTD1 transcripts and a mock empty vector has also been constructed to serve as a negative control.The circ RNA PCMTD1 was successfully over-regulated after transfected with circ RNA PCMTD1 vector in SCC-15 and the efficiency of over-regulation was by q RT-PCR analysis.Expressions of circ RNA PCMTD1 were no significant different in other cell lines.The proliferation,migration,invasion and apoptosis of Scc15 cell lines after circ RNA PCMTD1 vector transfected were obviously restrained.The relative proliferation rates of Scc15 were inhibited(circ RNA PCMTD1 vector compare to mock vector).The migration number was 910 ±54.75 vs 620 ±23.31(P<0.05)and the invasion number was 557 ±84.75 vs 180 ±20.31(P<0.05)in the SCC-15(circ RNA PCMTD1 vector compare to mock vector).The relative cell apoptosis rate of Scc15 was 23.15 % vs 6.74 %((P<0.05)(circ RNA PCMTD1 vector compare to mock vector).The relative cell cycle period of Scc15 was more inhibited in the S period when circ RNA PCMTD1 vector was transfected.The PI3K?AKT?BCL-2?Cyclin D1 protein level was decreased and BAX protein level was increased when circ RNA PCMTD1 vector compare to mock vector.Conclusion: Circ RNA PCMTD1 was significant down-regulated in the OSCC tissues.Circ RNA PCMTD1 could regulates the proliferation,migration,invasion and apoptosis of Scc15 cell lines by regulating the PI3 K /AKT signaling pathway.In the study,Circ RNA PCMTD1 might play an important role to contribute to the progression of oral squamous cell carcinoma.