Fig. 5

Promotion of epidermal differentiation of ME-CSCs in a co-culture in vitro model of cholesteatoma recurence. a The expression of different cytokeratins in ME-CSCs in the co-culture system after 14 days with or without treatment with LPS and with or without simultaneous co-culture with ME-CFs. Additionally the control of the untreated cells under standard culture conditions is shown. Only the co-culture treated with LPS showed a highly significant increase in the expression of these cytokeratins. b The expression of Ki-67 as marker for proliferation of the same samples depicted in (a). The mitotic activity is reduced for all samples relative to the control but the LPS treated co-culture shows a slight increase in Ki-67 expression relative to the other samples cultured for 14 days. c LSM imaging of ME-CSCs co-cultivated with fibroblasts in medium containing LPS or control medium. The immunofluorescence staining of cytokeratin 16, 19 reveals that these two cytokeratins are homogenously induced in ME-CSCs by stimulation of the fibroblasts. Cytokeratin 19 is also sparsely expressed in control culture (arrow). The expression of cytokeratin 18 is likewise induced in the stimulated culture, but also to a lesser extent in the control medium; (depicted: mean standard deviation; one tailed non paired t-test with 95% confidence interval upon passed Shapiro–Wilk normality test, *≤ 0.05, **≤ 0.01, ***≤ 0.001)