E3 ubiquitin ligase TRIM55 promotes metastasis of gastric cancer cells by mediating epithelial-mesenchymal transition

Figure 1 Representative images of immunohistochemical staining for TRIM55 in human gastric cancer tissue and its prognostic significance. A: Low expression of TRIM55 in gastric normal mucosa tissue; B: TRIM55 expression in well-differentiated adenocarcinoma; C: TRIM55 expression in poorly differentiated adenocarcinoma; D: Overexpression of TRIM55 in signet-ring cell carcinoma. Original magnification, 400 ×; E: TRIM55 protein levels in five tumor samples and their matched normal tissues; F: Overall survival curves for 91 gastric cancer (GC) patients according to TRIM55 protein expression (P = 0.026); G: Overall survival curves of TCGA GC patients with different TRIM55 expression. ^cP < 0.001. HR: Hazard ratio; GC: Gastric cancer.

Figure 2 TRIM55 expression in gastric cancer cells. A: The expression of TRIM protein was detected in gastric cancer (GC) cells by western blot. The histogram shows the expression of TRIM55 in GC cells was stronger than that in gastric mucosa cell line; B: The interference efficiency of TRIM55 small interfering RNA (siRNA) in SGC7901 cells was detected by Western blot; C: Quantitative real-time-polymerase chain reaction assay was performed to determine TRIM55 expression after transfection with siRNA; D: The up-regulation of TRIM55 expression in HGC27 cells was detected by Western blot; E: TRIM55 mRNA expression level in HGC27 after transfection with the TRIM55 plasmid. ^bP < 0.01; ^cP < 0.001.

Figure 3 TRIM55 regulates gastric cancer cell proliferation. A and B: Cell viability detected by cell counting kit-8 assay in SGC7901 cells after knockdown of TRIM55 and in HGC27 cells after overexpression of TRIM55; C and D: Colony formation analysis of TRIM55 knockdown-treated SGC7901 cells and TRIM55 overexpression-treated HGC27 cells. ^cP < 0.001.

Figure 4 TRIM55 promotes metastasis of gastric cancer cells. A: Migration and invasion analysis of TRIM55 knockdown-treated SGC7901 cells; B: Migration and invasion analysis of TRIM55 overexpression treated-HGC27 cells. ^cP < 0.001.

Figure 5 Wound healing assays were performed in gastric cancer cells. A: Migration rates of SGC7901 cells at 24 h were lower than that in control groups after knockdown of TRIM55; B: Migration rates of HGC27 cells at 24 h were higher than that in control groups after overexpression of TRIM55. ^cP < 0.001.

Figure 6 Western blot results of epithelial-mesenchymal transition pathway-related proteins in gastric cancer cells. A and B: Western blot analysis of E-cadherin, N-cadherin, Vimentin, ZEB1, and Snail after TRIM55 knockdown and overexpression in SGC7901 and HGC27 cells; C: Histogram of the expression of E-cadherin, N-cadherin, Vimentin, Snail, and ZEB1 proteins related to metastasis after knockdown or overexpression of TRIM55. ^cP < 0.001.