Fig. 1

Construction of in vitro model of CTC clusters and preliminary evaluation of its molecular characteristics. A Schematic of the experimental for cell clusters formation and evaluation. B Representative images of the appearance of MCF-7 cell clusters and CTC clusters from patients. Pan-Cytokeratin (Pan-CK) (green), DAPI (nuclei, blue). C Transmission Electron Microscope (TEM) images of MCF-7 cell clusters. J, cell–cell junction. D Left: tumor cell–cell adhesion test. The lower layer is MCF-7 cells, and the upper layer is MCF-7-GFP cells (green). Right: the quantitated results, n = 5, ***P < 0.001. E Western blot analysis of the protein levels of plakoglobin in MCF-7 adherent cells and cell clusters. F Q-PCR analysis of the mRNA levels of plakoglobin in MCF-7 adherent cells and cell clusters. n = 3, ***P < 0.001. G Adhesion molecules localization. MCF-7 adherent cells and cell clusters were stained for DAPI (nuclei, blue) and plakoglobin (red) by immunofluorescence assay. The quantitated results of plakoglobin are shown in (H), n = 5, *P < 0.05. I Immunofluorescence analysis of the protein levels difference of plakoglobin in MCF-7 single cells and cell clusters. DAPI (nuclei, blue), plakoglobin (red). Two tail student's t-test analysis was used to compare the statistical difference between indicated two groups in (D), (F), and (H)