ECRG4 as a novel tumor suppressor gene inhibits colorectal cancer cell growth in vitro and in vivo.

Esophageal cancer related gene 4 (ECRG4) as a tumor suppressor gene inhibits the growth and development of various tumors. Colorectal cancer (CRC), a common malignant tumor in the digestive tract worldwide, is a leading cause of death. The aim of our study was to assess the tumor-suppressing effect of ECRG4 on CRC and explore its related mechanisms in vitro and in vivo. The expression levels of ECRG4 were measured in colorectal cancer tissues and para-carcinoma tissues. ECRG4 gene was transfected into CRC cells to investigate its effect on cell proliferation by MTT, colony formation assay, and cell cycle analysis. Cell apoptosis was assessed by annexin-V/PI, Hoechst 33342 staining, and analysis of apoptosis-related protein expressions in vitro. The in vivo tumorigenesis assays were performed in nude mice. According to the results, there was a lower expression of ECRG4 in CRC tissues compared with normal tissues, which was strongly associated with histology differentiation and lymph node metastasis. Additionally, overexpression of ECRG4 had a significant inhibitory effect on proliferation and promoted apoptosis in Caco-2 and SW480 cells. Moreover, we found that the overexpression of ECRG4 inhibited tumorigenesis in vivo by diminishing the volume and weight of the tumors and inducing apoptosis of tumor cells. Our study indicates that ECRG4 may be a new potential target and prognostic factor for patients with CRC.