Fig 2: DEPDC1 promoted OSCC progression via the WNT/β-catenin signaling pathway. (A,B), Overexpression of DEPDC1 enhanced the migration and invasion of SCC9 and SCC15, while XAV939, an inhibitor of the WNT/β-catenin signaling pathway, could weaken the migration (SCC9 p = 0.0039; p = 0.0081, SCC15 p = 0.0024; p = 0.0134) and invasion ability (SCC9 p = 0.0005; p = 0.0138, SCC15 p = 0.0005; p = 0.0011) after overexpression of DEPDC1. (C), Meanwhile, upregulation of DEPDC1 induced higher N-cad (SCC9 p = 0.0024; p = 0.0042, SCC15 p = 0.0002; p = 0.0012) and β-catenin expression (SCC9 p = 0.0021; p = 0.0114, SCC15 p = 0.0014; p = 0.0075) and lower E-cad expression (SCC9 p = 0.0047; p = 0.0131, SCC15 p = 0.0064; p = 0.0004), while the protein level could also be reversed by XAV939. N-cad: N-cadherin, E-cad: E-cadherin, Con: control, OE: overexpression of DEPDC1. Significant differences were considered at p < 0.05 *; p < 0.01 **; p < 0.001 ***.

Fig 3: Knockdown of DEPDC1 inhibited the migration and invasion of OSCC. (A); (B), The migration (SCC9 p = 0.0012, SCC15 p = 0.0010) and invasion abilities (SCC9 p = 0.0002, SCC15 p = 0.0005) of SCC9 and SCC15 were inhibited after knockdown of DEPDC1. (C); Knockdown of DEPDC1 resulted in a decrease in N-cad (SCC9 p = 0.0024, SCC15 p = 0.0022) and β-catenin (SCC9 p = 0.0007, SCC15 p < 0.0001), and an increase in E-cad (SCC9 p = 0.0102, SCC15 p = 0.0040). Error bars in the graphs represent S.D. N-cad: N-cadherin, E-cad: E-cadherin, siNC: negative control of siRNA, si-DEPDC1: knockdown of DEPDC1. Significant differences were considered at p < 0.05 *; p < 0.01 **; p < 0.001 ***; and p < 0.0001 ****.

Fig 4: Identification of prognostic Cox model. The expression level of 3 genes, DEPDC1 ((A), p < 0.0001), DDIT4 ((B), p = 0.0008) and SLC16A3 ((C), p < 0.0001), included in the risk Cox formula in TCGA. Triangle and square stand for gene expression level in normal and tumor samples, respectively. (D); Survival analysis between high- and low-risk levels according to risk scores calculated from the DEPDC1, DDIT4 and SLC16A3 expression profiles of each patient. (E,F), Univariate and multivariate Cox regression analyses on the basis of risk score. (G), High risk score might mean poor grade level in OSCC. Significant differences were considered at p < 0.001 ***; and p < 0.0001 ****.

Fig 5: DEPDC1 was identified as a potential biomarker. (A), Survival analysis showed that high DEPDC1 expression levels meant poor overall survival. (B,C), DEPDC1 expression level was related to advanced stage and lymph node metastasis in OSCC. (D,E), GSEA suggested that high DEPDC1 expression was associated with higher activation of the WNT/β−catenin signaling pathway.