EGFL6 Modulates WNT Signaling to Drive Esophageal Cancer Metastasis and Proliferation

Abstract Background Esophageal cancer (EC) is the sixth deadliest cancer in the world. There has been no breakthrough in the research on EC in the past few decades. Epidermal growth factor-like protein 6 (EGFL6), as a member of the epidermal growth factor superfamily, plays an important role in the occurrence and development of some tumors. However, the role of EGFL6 in the EC has never explored. Methods Immunohistochemical staining was used to evaluate the expression level of EGEC6 protein in human EC and its adjacent non-tumor tissues, and analyzed the correlation between the expression level of EGFL6 protein and clinical pathological indexes and survival rate. In vitro, by constructing EGFL6 silence and overexpressed EC cells,used CCK-8, clone formation, wound healing assays, transwell experiment and flow cytometry to explore the effects of EGFL6 on the proliferation, invasion, migration and apoptosis of EC. By using real-time PCR or western blot to detect the related marker genes of epithelial-mesenchymal transformation (EMT), tumor stem cells (TSCs) and Wnt/β-catenin. In vivo, established a nude mouse EC transplantation tumor model. Results The results showed that the expression level of EGFL6 in EC is significantly higher than that in adjacent non-tumor tissues, and is related to poor prognosis of patients. In vitro, CCK-8, clone formation, wound healing assays, transwell experiment and flow cytometry results show that EGFL6 overexpression can promotes proliferation, invasion and migration of EC cells and inhibits apoptosis. EGFL6 silencing inhibits proliferation, invasion and migration of EC cells and promotes apoptosis. Real-time PCR and Western-blot detection of EMT-related markers found that EGFL6 can induce EC cells EMT. Real-time PCR detection of esophageal cancer stem cell-related genes showed that EGFL6 may maintain the expression of esophageal cancer stem cell-like cell population. Western-blot detection of Wnt/β-catenin signaling marker genes showed that EGFL6 participated in the expression of Wnt/β-catenin signaling pathway. In vivo experiments found that knockout of EGFL6 could inhibit the formation of subcutaneous tumors in nude mice. Conclusion Taken together, our study identified a novel role and mechanism of EGFL6 in EC and provided epigenetic therapeutic strategies for the treatment of EC.