Biological characteristics of human breast cancer mammospheres cultured in serum-free medium over long term / 肿瘤

ABSTRACT

Objective:To isolate breast cancer stem/progenitor cells from human breast cancer and study their proliferation and differentiation biological characteristics over long-term passages in vitro. Methods:Human breast cancer stem/progenitor cells were enriched in suspension cultures as nonadherent mammospheres(MS). Serial sphere formation assay was performed to determine self-renewal ability of mammosphere-derived cells (MSDC). Differentiation was induced by culturing MSDC in DMEM-F12 supplemented with serum but without growth factors. The ratio of CD44~+/CD24~(-/low) cell population was evaluated by flow cytometry(FCM). Results:The mammospheres were formed after inoculation of primary breast cancer cells into culcutre medium with growth factors but without serum. The mammospheres contained undifferentiated cells similar to stem cells, which had self-renewal and extensive proliferation capabilities. With increasing passages, the cells tended to adhere and differentiate. The number of adhering and differentiating cells increased, and the amount and size of mammospheres decreased. The CD44~+/CD24~(-/low) cell population was enriched in the basal-like molecular subtype of human breast tumors. The biological behaviors of mammospheres varied between different specimens.Conclusion:Cancer cells with stem cell properties of self-renewal, indefinite proliferation and multi-lineage differentiation widely existed in human breast cancer tissues. The biological behaviors varied because of different origin of specimens and changed under the effects of environmental factors.