UGT8 positively correlates with Sox10 and is a direct transcriptional target of Sox10. (A) Analysis of GSE25066 and TCGA datasets for the expression of UGT8 and Sox10. The relative level of UGT8 was plotted against that of Sox10. Correlations were analyzed using Pearson’s correlation method and Spearman’s rank correlation test. (B) Box plots indicated Sox10 mRNA expression in different subtypes of breast cancer from GSE25066 and TCGA datasets. Comparisons were analyzed by one-way ANOVA. (C) Expression of UGT8 and Sox10 was analyzed by quantitative RT-PCR in SUM159 and MDA-MB436 cells infected with empty vector or Sox10-expressing vector. Data are shown as mean ± SD based on three independent experiments. *, P < 0.01 by Student's t test. (D) Expression of UGT8 and Sox10 was examined by Western blotting in SUM159 and MDA-MB436 cells infected with empty vector or Sox10-expressing vector. (E) Schematic diagram showing positions of potential Sox10-binding motifs in UGT8 promoter. UGT8 promoter luciferase construct and mutated derivatives were also shown. Sox10 consensus sequence: (A/T)(A/T)CAA(A/T)G. (F) UGT8 promoter luciferase construct (wtU) was coexpressed with empty vector or Sox10-expressing vector in HeLa, SUM159, and MDA-MB436 cells, respectively. After 48 h, luciferase activities were analyzed (mean ± SD in three separate experiments). (G) UGT8 promoter luciferase construct (wtU) as well as its mutants (mutU1, mutU2, and mutU3) were coexpressed with empty vector or Sox10-expressing vector in HEK-293T cells. Luciferase activities were analyzed as in F. Data are shown as mean ± SD based on three independent experiments. (H) ChIP analysis for binding of Sox10 to the UGT8 promoter in MDA-MB231 and HCC1428 cells.