Figure 10A RARα1/3 plasmid construct and the corresponding control void vector were stably transfected into ATRA-resistantMDA-MB453 cells. Two cell clones over-expressing RARα (RARA-C5 andRARA-C7) and two appropriate control clones (Vect-C1 andVect-C2) were isolated. A RARα3 shRNA plasmid construct and the corresponding void vector were stably transfected into ATRA-sensitiveSKBR3 cells. After selection, two cell clones silenced for RARα3 (RARA-sh18 andRARA-sh19) and two appropriate control clones (Vect-C6 andVect-C8) were isolated.A, D The indicated clones and the parental cell line (WT) were transiently transfected with the RARE-DR5-Lucretinoid reporter construct and the level of luciferase activity was measured 24 h after treatment with vehicle (DMSO) and ATRA (100 nM), as illustrated in the upper bar graph. Each value is the mean ± SD of three replicate cultures. The levels of the RARα protein measured in the indicated clones by Western blotanalysis is shown under the bar graph. To demonstrate that similar levels of total proteins were loaded in each lane, the β-actin band signal obtained after re-blotting of the gel is shown. FI = Fluorescence intensity.B, E The panels illustrate the growth curves of the indicated MDA-MB453 and SKBR3 clones and the SKBR3 parental cell lines (WT) measured with the sulforhodamine assay.C The bar graphs illustrate the effect of increasing concentrations of ATRA on the growth of the indicated MDA-MB453 clones and the parental cell line. The cell lines were challenged with vehicle (DMSO) or ATRA for 3, 6, and 9 days prior to the sulforhodamine assay. OD = optical density at 540 nm. Each value is the mean ± SD of five replicate culture wells.A, D The indicated clones and the parental cell line (WT) were transiently transfected with the RARE-DR5-Lucretinoid reporter construct and the level of luciferase activity was measured 24 h after treatment with vehicle (DMSO) and ATRA (100 nM), as illustrated in the upper bar graph. Each value is the mean ± SD of three replicate cultures. The levels of the RARαprotein measured in the indicated clones by Western blot analysis is shown under the bar graph. To demonstrate that similar levels of total proteins were loaded in each lane, the β-actin band signal obtained after re-blotting of the gel is shown. FI = Fluorescence intensity.B, E The panels illustrate the growth curves of the indicated MDA-MB453 and SKBR3 clones and the SKBR3 parental cell lines (WT) measured with the sulforhodamine assay.C The bar graphs illustrate the effect of increasing concentrations of ATRA on the growth of the indicated MDA-MB453 clones and the parental cell line. The cell lines were challenged with vehicle (DMSO) or ATRA for 3, 6, and 9 days prior to the sulforhodamine assay. OD = optical density at 540 nm. Each value is the mean ± SD of five replicate culture wells.A, D The indicated clones and the parental cell line (WT) were transiently transfected with the RARE-DR5-Lucretinoid reporter construct and the level of luciferase activity was measured 24 h after treatment with vehicle (DMSO) and ATRA (100 nM), as illustrated in the upper bar graph. Each value is the mean ± SD of three replicate cultures. The levels of the RARαprotein measured in the indicated clones by Western blotanalysis is shown under the bar graph. To demonstrate that similar levels of total proteins were loaded in each lane, the β-actin band signal obtained after re-blotting of the gel is shown. FI = Fluorescence intensity.B, E The panels illustrate the growth curves of the indicated MDA-MB453 and SKBR3 clones and the SKBR3 parental cell lines (WT) measured with the sulforhodamine assay.C The bar graphs illustrate the effect of increasing concentrations of ATRA on the growth of the indicated MDA-MB453 clones and the parental cell line. The cell lines were challenged with vehicle (DMSO) or ATRA for 3, 6, and 9 days prior to the sulforhodamine assay. OD = optical density at 540 nm. Each value is the mean ± SD of five replicate culture wells.F The graphs illustrate the effect of increasing concentrations of ATRA on the growth of the indicated SKBR3 clones and the parental cell line. The cell lines were challenged with vehicle (DMSO) or ATRA for 3 and 6 days prior to the sulforhodamine assay. Each value is the mean ± SD of five replicate culture wells.G The panel illustrates the effects exerted by ATRA (0.1 μM) on random cell motility of the indicated MDA-MB453 and SKBR3 clones. The results are representative of two independent experiments. Each value is the mean ± SE of the motility of at least 60 cells.