Dermcidin as a novel binding protein of lncRNA STCAT3 and its effect on prognosis in gastric cancer

Long non-coding RNAs (lncRNAs) perform distinct biological functions by regulating gene expression through various molecular mechanisms under normal physiological and pathological conditions. However, the function of the stomach cancer-associated transcript-3 (STCAT3) lncRNA, including its prognostic significance and role as a binding protein in gastric cancer (GC), remain unclear. In the present study, 56 potential binding proteins of STCAT3 were screened using through mass spectrometry and bioinformatics analysis. Among these, dermcidin, GAPDH, annexin, calmodulin-like protein, cathepsin-D and suprabasin were demonstrated to be candidate binding proteins using a literature search. RNA-protein interaction prediction was used to confirm these six proteins. Finally, dermcidin was identified as the binding protein of STCAT3 by comparing the mRNA and protein levels of the candidate genes and their correlations with STCAT3 in plasmid-transfected BGC-823 GC cell lines, as well as by validating the interplay between dermcidin and STCAT3 in other GC cell lines. Immunohistochemical analysis of tissues from 98 patients with GC further confirmed the interaction between dermcidin and STCAT3. The results of the present study also revealed that STCAT3 and dermcidin and independent predictors of overall survival in patients with GC. Furthermore STCAT3 and dermcidin are positively correlated with lymph node metastasis and tumor/node/metastasis score. In summary, the present study suggests that dermcidin is a novel binding protein of lncRNA STCAT3, which serves an important role in the progress and clinical outcome of GC.