Figure 4.

RORα suppresses mammosphere formation.A, RORα expression in 2D cultured cells and mammospheres was examined by Western blot. B and C, analysis of mammosphere formation in control and RORα-silencing MCF10A cells. Bar represents 100 μm. n = 3. ∗p < 0.01. D and E, tumorsphere assay analyzing the tumorsphere formation in control and RORα-expressing MDA-MB 231 cells, MDA-MB 157 cells, and BT549 cells. Bar represents 100 μm; n = 3. ∗p < 0.01. F, analysis of tumorsphere-forming abilities of MDA-MB 231 cells or HMT-3522 T4-2 cells (T4) that were pretreated with the RORα antagonist SR1001 (10 μM, 20 μM) or agonist SR1078 (5 μM, 10 μM) in pHEMA-treated (nonattached) plates and incubated in 37 °C, 5% CO₂, for 5 days. Bar represents 100 μm. pHEMA, poly(2-hydroxyethyl methacrylate); RORα, retinoid orphan nuclear receptor alpha.