The feasible role of soluble E‑cadherin in spheroidogenesis of HCT116 colorectal cancer cells, a candidate biomarker for liquid biopsy.

Although E-cadherin is known as a tumor suppressor via its effects on cell to cell adhesion, the effects of E-cadherin on malignant transformation have not yet been thoroughly investigated. In the present study, after malignant transformation was induced by spheroid formation in a fetal bovine serum-supplemented environment, the effects of soluble E-cadherin on the spheroidogenesis of colorectal cancer cells were investigated. E-cadherin knock-out (KO) was performed in HCT116 cells, targeting exon 3 of the CDH1 gene. A cell viability assay was performed to determine the proliferation and viability of wild type and CDH1 KO HCT116 cells after treatment with anticancer drugs. Spheroidogenesis was compared with or without exogenous E-cadherin, antibody against the ectodomain of E-cadherin (DECMA-1) and PD98059 treatment. In addition, morphometry, immunocytochemistry and western blotting were performed. Soluble E-cadherin in culture media was measured using an enzyme-linked immunosorbent assay. Firstly, CDH1 KO was confirmed by western blotting. Notably, the proliferation and viability of cells following treatment with 5-fluorouracil, epidermal growth factor receptor inhibitor and src kinase inhibitor were similar between the cell lines. Exogenous E-cadherin or DECMA-1 treatment did not affect spheroidogenesis, although long-term maintenance was slightly disturbed in CDH1 KO spheroids compared with that in wild type spheroids. In addition, E-cadherin was increased in spheroid culture as compared with that in conventional culture. Soluble E-cadherin was increased in a time-dependent manner, particularly in wild type HCT116 cells. PD98059 inhibited ERK activation and enhanced E-cadherin expression in conventional culture without affecting spheroidogenesis. These results suggested that soluble E-cadherin may be considered as a biomarker for colorectal cancer, although exogenous E-cadherin might not have a further role in malignant transformation.