Fig. 4: Knockdown of KRT8 in chordoma cell increased its’ sensitivity to chemotherapy by promoting its apoptosis in vitro.

Chordoma cell line CM319 and UCH1 were transfected with siKRT8 followed by treatment of doxorubicin (0.5 μM) or irinotecan (50 μM) for 24 h. a Cell viability of chordoma cells were determined by CCK8 assay. b Western blotting analysis and quantification of KRT8, cleaved PARP, and Caspase 4 protein expression (normalized to GAPDH expression, quantification data of KRT8 in the “Doxo 24 h” group and “Irino 24h” group were derived from the same data set in Fig. 1b). c Immunofluorescence staining of KRT8 of CM319 and UCH1 cell line. d Apoptosis of chordoma cells was determined by Annexin V-PE/PI staining measured by flow cytometry (n = 3, *p < 0.05 vs. indicated group, **p < 0.01 vs. indicated group, NS: not statistically significant vs. indicated group, Con: control group, Doxo: doxorubicin-treated group, Irino: irinotecan-treated group. Scale bar = 50 μm. For all the above-mentioned statistical analyses, significance was determined by one-way ANOVA followed by Tukey’s multiple comparisons test and the results were shown as mean ± S.D.).