Fig. 4

ALDH1A1 positively regulates AURKA protein levels by preventing its degradation. a ALDH1A1 overexpression increases AURKA levels. Wild-type HA-tagged ALDH1A1-BxPC3 cells were generated by infecting the corresponding retrovirus. b ALDH1A1 knock-down using two different ALDH1A1 shRNAs depletes AURKA in BxPC3 cells. Cells were transfected with scrambled shRNA (lane 1), ALDH1A1-shRNA1 or 2 (lanes 2 and 3, respectively), and AURKA and ALDH1A1 levels were analyzed after 30 h. c Histogram shows relative band intensities normalized to the corresponding tubulin level. Data shown are mean ± SEM of three independent experiments. * and # indicate statistically significant differences with respect to controls for ALDH1A1 and AURKA proteins, respectively. p < 0.05 analyzed by two-way analysis of variance. d ALDH1A1 overexpression increases AURKA levels in Panc1 cells. e Histogram shows relative band intensities normalized to the corresponding tubulin level. Data shown as mean ± SEM of three independent experiments. * and # indicate statistically significant differences with respect to controls for ALDH1A1 and AURKA proteins, respectively. p < 0.05 analyzed by two-way analysis of variance. f ALDH1A1 depletion decreases AURKA levels in Panc1 cells. g Histogram shows relative band intensities normalized to the corresponding tubulin level. Data shown as mean ± SEM of three independent experiments. h ALDH1A1 inhibits AURKA degradation. i Graphical representation of ALDH1A1 degradation rate. The significance of the difference between means was determined by Duncan’s multiple range test, *p < 0.05. j Graphical representation of AURKA degradation rate, *p < 0.05. k ALDH1A1 stabilizes AURKA by inhibiting its ubiquitylation. Each experiment was done at least three independent times. Representative data are shown. Data used to generate the summary statistics shown in panels c, e, and g are reported in Additional file 4