Fig. 5

CDK1 regulated cancer stemness through phosphorylating STAT3. a Silencing CDK1 reduced phosphorylation of STAT3 Y705. CDK1-WT and CDK1-K33R was overexpressed in CDK1 silencing PANC-1 cells. Western blot analysis showed that silencing CDK1 decreased levels fo CD44, Sox2 and p-STAT3 (Y705), which can be rescued by over-expressing CDK1-WT not its mutant. b Flow cytometry showed that over-expressing CDK1-WT not K33R mutant rescued decreasing of CD44+/CD24+ cancer stem cells in PDAC. Data are presented as mean ± SD (n = 3) *P < 0.05. c, d Sphere formation assay showed that over-expressing CDK1-WT not K33R mutant contributed to tumor stemness in PDAC cells. Data are from three independent experiments. Scale bars, 100 μm. *P < 0.05. e Expressions of CD44 and Sox2 in STAT3 silencing PANC-1 cells were examined by western blot. f, g Silencing STAT3 inhibited tumor stemness in PDAC cells. Sphere formation assay was used to detect cancer stemness in STAT3 silencing PDAC cells. Data are presented as mean ± SD (n = 3). Scale bars, 100 μm. *P < 0.05. h Western blot analysis showed that silencing STAT3 reduced levels fo CD44 and Sox2, which can be rescued by over-expressing STAT3 wild type. i, j STAT3 contributed to maintaining of tumor stemness in PDAC cells. Sphere formation assay indicated that over-expressing STAT3 enhanced sphere forming capacity which was impaired by silencing STAT3 in PDAC cells. Data are from three independent experiments. Scale bar, 100 μm. *P < 0.05