Diagnostic Efficacy Evaluation And Biological Function Of Differentially Expressed LncRNA C5orf66-AS1 In Gastric Cancer

Background:Long non-coding RNAs(lnc RNA)play a critical role in tumorigenesis.The studies of gastric cancer(GC)associated lnc RNAs help us to analyze the mechanism of GC development from the perspective of gene regulation.In our previous study,C5orf66-AS1 was authenticated by lnc RNA-m RNA co-expression microarray with aberrant expression in tissues of GC.Based on this work,we examined the expression pattern of C5orf66-AS1 in GC tissue and gastric disease serum samples,and explored the value of C5orf66-AS1 as a diagnostic marker for GC.Further,the vitro experiments were used to analyze the effects of C5orf66-AS1 on the biological function in GC cell lines.Methods:A total of 630 samples included 76 GC tissues and the paired adjacent nontumor tissue and 478 serum samples,of which serum samples were made up of 134 cases of superficial gastritis(GS),102 cases of atrophic gastritis(GA),42 cases of Gastric dysplasia(GD)and 200 cases of gastric cancer(GC)including 59 cases of early gastric cancer(EGC)and 141 cases of advanced gastric cancer(AGC).The expression levels of C5orf66-AS1 in GC tissues,serum and cell lines were detected by quantitative real-time PCR(q RT-PCR).CCK-8 assay,Transwell assay,and wound healing assay were performed to determine whether the C5orf66-AS1 could affect GC tumorigenesis and progression.The receiver performance curve(ROC)was used for diagnostic efficacy evaluation,and the area under the curve(AUC),sensitivity,and specificity were calculated.Results:The expression of C5orf66-AS1 was down-regulated in GC compared with the adjacent normal tissues(NATs)(P<0.001).Serum C5orf66-AS1 levels were significantly decreased in GC patients than those in GS and GA patients(P<0.001).C5orf66-AS1 was a protective factor for GD(OR 24.91,95%CI 8.31-74.6,P <0.001)and GC(OR 5.62,95%CI 3.48-9.10,P <0.001).For GC,the AUC was 0.688(95% CI,0.644-0.729;P<0.001),and sensitivity and specificity were 77.5% and 53.6%,respectively.In particularly,for GD+EGC,the AUC was 0.789(95%CI,0.750-0.825;P<0.001),and sensitivity 85.15%,and specificity 62.86%.The growth of AGS with GV144-C5orf66-AS1 transfected was significantly slowed.The results of Transwell and Wound scratch assay showed that the AGS-C5orf66-AS1 were significantly less invasive and metastatic than the control cells AGS-NC.Conclusion: Decreased expression level of C5orf66-AS1 in serum has good diagnostic efficiency for GC,especially for early diagnosis.C5orf66-AS1 could suppress the proliferative,migratory and invasive gastric carcinoma cells.