Involvement of breast cancer stem cells in tumor angiogenesis

The aim of the present study was to investigate the role of breast cancer stem cells (BCSCs) in the angiogenesis of breast cancer tumors. The expression levels of mutant p53, cluster of differentiation (CD)31, vascular endothelial factor (VEGF), in addition to human epidermal growth factor (HER)2, were detected in the blood vessels of human breast cancer (BC) tissue samples. CD44⁺/CD24^-/low cells were selected from single-cell suspensions of BC tissues to assess the expression of CD31 and CD105, in addition to the ability of these cells to metabolize acetylated low-density lipoprotein (Ac-LDL). Furthermore, vascular-like structures were observed histologically. Mutant p53, CD31 and VEGF were all expressed in these tissues. CD44⁺ cells comprised 7.5±2.6 and 94.3±4.7% of the cell population prior to and following sorting, respectively. CD24⁺ cells comprised 48.2±9.4 and 4.3±4% of the cell population prior to and following sorting, respectively. A low proportion of CD24⁺ cells corresponded to a high proportion of CD24^-/low cells. The percentages of CD105⁺ and CD31⁺ glomus cells in the mammary gland were 4.5±0.9 and 6.2±1.3%, respectively, and following passaging for three generations, these increased to 79.6±9.3 and 84.1±10.7%, respectively (P<0.05). Cells were cultured using an endothelial cell culture system, and they internalized DiL-Ac-LDL. Here, vascular endothelial cells formed vascular-like structures, whereas the control group demonstrated no such structures. Overall, the results suggest that BCSCs-derived endothelial cells may contribute to tumor angiogenesis.