TMEM211 Promotes Tumor Progression and Metastasis in Colon Cancer

Abstract

Colon cancer is the third most important cancer type, leading to a remarkable number of deaths, indicating the necessity of new biomarkers and therapeutic targets for colon cancer patients. Several transmembrane proteins (TMEMs) are associated with tumor progression and cancer malignancy. However, the clinical significance and biological roles of TMEM211 in cancer, especially in colon cancer, are still unknown. In this study, we found that TMEM211 was highly expressed in tumor tissues and the increased TMEM211 was associated with poor prognosis in colon cancer patients from The Cancer Genome Atlas (TCGA) database. We also showed that abilities regarding migration and invasion were reduced in TMEM211-silenced colon cancer cells (HCT116 and DLD-1). Moreover, TMEM211-silenced colon cancer cells showed decreased levels of Twist1, N-cadherin, Snail and Slug but increased levels of E-cadherin. Levels of phosphorylated ERK, AKT and RelA (NF-κB p65) were also decreased in TMEM211-silenced colon cancer cells. Our findings indicate that TMEM211 regulates epithelial-mesenchymal transition for metastasis through coactivating the ERK, AKT and NF-κB signaling pathways, which might provide a potential prognostic biomarker or therapeutic target for colon cancer patients in the future.

Keywords: colon cancer; epithelial–mesenchymal transition; prognosis; signaling pathways; transmembrane protein 211.

Figure 1

TMEM211 expression and its association with prognosis in colon cancer patients from the TCGA database. TMEM211 expressions were compared between (A) 41 normal and 286 tumor tissues of colon cancer patients or (B) corresponding adjacent normal and tumor tissues from 26 paired colon cancer patients. The correlation of TMEM211 expression with DSS in colon cancer patients stratified with (C) smaller tumor size (T1 + T2) and (D) larger tumor size (T3 + T4) was analyzed using the Kaplan–Meier method and the log-rank test (the p-value of significance is *** p < 0.001).

Figure 2

Invasion, migration and EMT marker expression in TMEM211-silenced colon cancer cells. (A) The efficiency of TMEM211 gene-silencing was analyzed by RT-PCR. (B) Cell invasion was measured by transwell migration assay. (C) Cell migration was measured by wound-healing assay. (D) The mRNA levels of E-cadherin (E-Cad), N-cadherin (N-Cad), Snail, Twist-1 and Slug were analyzed by RT-PCR. All HCT116 and DLD-1 cells were silenced with scramble siRNA (5 nM, siCtrl) or siRNAs against TMEM211 (5 nM, siTMEM211) for 72 h (p-values of significance are * p < 0.05; ** p < 0.01; *** p < 0.001).

Figure 3

Expressions of molecules related to ERK, AKT and NF-κB signaling pathways in TMEM211-silenced colon cancer cells. (A) The levels of total and phosphorylated ERK1/2, AKT, RelA were analyzed using Western blotting. The β-actin (ACTB) was used as loading control. (B) The quantified levels of p-ERK1/2, p-AKT and p-RelA. All HCT116 and DLD-1 cells were silenced with scramble siRNA (5 nM, siCtrl) or siRNAs against TMEM211 (5 nM, siTMEM211) for 72 h. (p-values of significance are * p < 0.05; ** p < 0.01; *** p < 0.001).

Figure 4

The interaction of TMEM211 and its associated proteins was analyzed using the STRING database (https://string-db.org, accessed on 2 July 2020).