Figure 2. Upregulation of miRNA-205 is associated with the tamoxifen resistance of breast cancer cells (BCCs). (A) Volcano plot of miRNA profile in BCCs and M/T cells, as determined by microarray analysis. (B) The expressions of miRNAs in BCCs and M/T cells, as shown through the heat map. (C) The expression of miRNA-205 in exosomes isolated from BCCs and M/T cells. (D) Graphic illustration of the coculture system. The M/T cells (upper chamber) and BCCs (lower chamber) were separated by a 0.4 μm pore membrane, which only allows the passage of exosomes, but not large molecules. (E) PKH26-labeled (red fluorescence) M/T exosomes were taken up by DAPI-stained BCCs (blue fluorescence), as photographed using the confocal microscopy. Scale bar = 25 μm. (F) The expression of miRNA-205 in BCCs treated with PBS or M/T-Exo. (G) Cell viability of BCCs treated with PBS or M/T-Exo. Values are means ± SD. *P < 0.05; **P < 0.01, ***P < 0.001. At least three replicates were available for analysis in each treatment group.