Fig. 2

Sorafenib induced autophagy and upregulated the expression of PPT1 in sorafenib-resistant HCC cells. A Western blot showing increase in LC3-II in HCC cells after treatment with sorafenib (10 µΜ, 24 h). B Photographs from transmission electron microscopy showing an increase in autophagosomes in HCC cells after treatment with sorafenib (10 µΜ, 24 h). Scale bar, 2 μm. C Fluorescence microscopic images showing punctate fluorescence from transfected mCherry-GFP-LC3 constructs in HCC cells treated with sorafenib (10 µΜ, 24 h); nuclei are labeled with Hoechst 33,258. Arrowheads indicate typical examples of co-localized particles of GFP and mCherry signal, while the arrow points to a typical example of a particle with an mCherry signal but without GFP signal. Scale bar, 10 μm. D IC50 values of sorafenib (48 h) for Hep 3B, Hep 3B-SR, Hep 1–6, and Hep 1-6-SR cells determined by CCK-8 assay. The data shown are from three independent experiments. E Confirmation of the upregulation of PPT1 protein in sorafenib-resistant cells derived from Hep 3B and Hep 1–6 by Western blot analysis