Fig. 6

CD73 triggers SOX9 transcription by c-Myc and enhances Sox9 protein stability via inhibiting GSK3β activity. a Correlations between CD73, c-Myc, and SOX9 mRNA levels were analyzed based on RT-PCR results from our cohort (upper panel) and RNA-sequencing data from TCGA database (lower panel). b Effects of c-Myc knockdown (upper) or c-Myc antagonist treatment (lower) on SOX9 mRNA and protein expression levels in CD73-high HCC cells. c Effects of c-Myc knockdown (upper) or c-Myc antagonist treatment (lower) on SOX9 mRNA and protein expression levels in CD73-overexpressed HCC cells. d HepG2 (left) and MHCC97L (right) cells were co-transfected with indicated plasmids and the activities of SOX9 promoter were assessed by luciferase reporter assays. e Effects of proteasome degradation inhibitor, MG132, on protein expression level of SOX9 in CD73-knockdown Hep3B (upper) and HCCLM3 (lower) cells. f SOX9 protein stability in HCC cells received indicated treatments and exposed to a time-course treatment with CHX. g Ubiquitination assay of SOX9 in Hep3B (left) or HCCLM3 (right) cells received indicated treatments. Transfected cells were treated with MG132 for 6 h. h Ubiquitination assay of SOX9 in HepG2 (left) or MHCC97L (right) cells received indicated treatments. i Simplified diagram of the present study. Transfected cells were treated with MG132 for 6 h. Throughout the figure, “*” indicated P < 0.05, “**” indicated P < 0.01, and “***” indicated P < 0.001 by two-tailed t test or Mann–Whitney test