Figure 2. MEL-18 positively regulates ESR1 and PR expression.
(A) Heatmap generated from the microarray analysis of MCF-7 cells expressing either control (shCon) or MEL-18 shRNA (shMEL) showing the differential expression of the luminal and basal markers between the two groups. The Venn diagram shows the number of common genes between the MEL-18 target genes and the PAM305 gene list. (B) The MEL-18 target genes obtained from the microarray analysis were categorized according to gene function via GO enrichment analysis. (C) The MEL-18–silenced (shMEL) or MEL-18–overexpressing (MEL-18) breast cancer cells and control cells (shCon and Con) were cultured in DMEM containing 10% FBS for 48 hours, and the cell lysates were subjected to immunoblotting using the indicated antibodies. To detect ER-α protein expression in TNBC cells, more than 100 μg of lysate was used for immunoblotting. The relative immunoblot band densities are indicated at the bottom of each blot. n.d., not detected. A black line within the blot indicates that the bands were spliced from the equal lane in the same gel because of the expression of isoforms of PR at different molecular weights (lower, PR-A, 81 kDa; upper, PR-B, 116 kDa). The data are representative of three independent experiments. (D and E) The mRNA levels of ER-α (ESR1) in the indicated stable cell lines were validated via qRT-PCR. The data represent the mean ± SD of triplicate measurements. *P < 0.05 vs. the controls (shCon or Con) based on 2-tailed Student’s t test.