Effect of cell density on the malignant biological behavior of breast cancer by altering the subcellular localization of ANXA2 and its clinical implications

Objective To investigate the subcellular localization of ANXA2 in breast cancer of different cell densities in humans and its relationship with the clinicopathological features of patients. To investigate the differences in ANXA2 subcellular localization in MDA-MB-231 cells of different cell densities. To compare the proliferation, invasion, and migration ability of MDA-MB-231 cells under different ANXA2 subcellular localization. Methods Immunohistochemistry was applied to detect the subcellular localization of ANXA2 in tissue sections of 60 breast cancer patients, and the association with ANXA2 subcellular localization was verified in conjunction with cell density. To investigate the relationship between cell density and clinicopathological data of breast cancer patients. To establish high- and low-density models of MDA-MB-231 breast cancer cell lines and verify the subcellular localization of ANXA2 using immunofluorescence and observation under confocal microscopy. The proliferation, migration, and invasion ability of MDA-MB-231 cells under different subcellular localization of ANXA2 were detected and compared using CCK-8 assay and Transwell assay. After changing the subcellular localization of ANXA2 in high-density MDA-MB-231 cells with PY-60, changes in biological behaviors of the compared MDA-MB-231 cells were observed. Two different 4T1 cell lines with high and low densities were implanted subcutaneously in nude mice to observe the effects of different cell densities on tumor growth in nude mice. Results The clinical data showed that breast cancer with high cell density had higher T stage and higher TNM stage, and the cell density was positively correlated with breast cancer mass size. ANXA2 was mainly localized to the cell membrane when the cell density of breast cancer cells was high and to the cytoplasm when the cell density was low. The CCK-8 assay showed that the proliferation rate of MDA-MB-231 cells increased ( P