Increased soluble E‑cadherin of spheroid formation supplemented with fetal bovine serum in colorectal cancer cells

Abstract

Cancer stem cells (CSCs) are known to be a major cause of metastasis, resistance and recurrence. Spheroid formation is one of the methods used to recruit CSCs utilizing an anchorage‑independent environment in vitro. It was aimed to investigate the availability of spheroid formation culture methods in the research field of CSCs and resistance using 5‑fluorouracil (5‑FU)‑resistant colorectal cancer cells. The wild type SNU‑C5 and 5‑FU‑resistant SNU‑C5 (SNU‑C5/5‑FUR) cells were cultured as usual (monolayer), and in 3‑dimensional non‑adhesive environments supplemented with fetal bovine serum (FBS) or growth factors, respectively. The character‑ istics of the spheroids were evaluated by morphometry, cell viability assay, western blotting, immunocytochemistry and enzyme‑linked immunosorbent assay. Spheroid formation was induced in an environment supplemented with FBS, while SNU‑C5/5‑FUR cells only formed spheres in media supple‑ mented with GFs. Sphere‑formed cells showed slower cell proliferation than cells from monolayer, which coincided with an increased level of p21 and a decreased level of β‑catenin. Markers for CSCs and drug resistance were not significantly changed after spheroid formation. Sphere‑formed cells showed significantly increased levels of soluble E‑cadherin, particu‑ larly in the environment supplemented with FBS. These results suggested that spheroid formation may be related to soluble E‑cadherin, but is not related to CSCs or resistance markers.