Figure 7

STC1 enhanced TMZ-induced DNA damage through STAT3-mediated inhibition of MGMT expression. (A, D) Representative images (left panel) and quantification (right panel) of comet assay on STC1-overexpressing (A) or STC1-knockdown (D) DBTRG cells treated with vehicle or 200 μM TMZ for 72 h. (B, E) Western blot results shows the protein expression of double-stranded DNA break marker γ-H2AX, the total H2AX and MGMT in STC1-overexpressing (B) or STC1-knockdown (D) DBTRG cells treated with vehicle or 200 μM TMZ for 72 h. (C, F) Representative images (left panel) and quantification (right panel) of γ-H2AX foci staining on STC1-overexpressing (C) or STC1-knockdown (F) DBTRG cells treated with vehicle or 200 μM TMZ for 72 h (scale bar, 100 μm). (G, I) Representative images of immunohistochemistry staining (left panels) and quantification (right panels) of STC1 and MGMT on tumor tissues of mice with intracranial injection of STC1-overexpressing (G) or STC1-knockdown (I) DBTRG cells and treated with vehicle or TMZ (scale bar, 100 μm). (H, J) Western blot results show the protein levels of phosphorylated STAT3 (p-STAT3(Y705)), STAT3 and MGMT in STC1-overexpressing (H) or STC1-knockdown (J) DBTRG cells treated with vehicle or 200 μM TMZ for 72 h. **: p < 0.01, ***: p < 0.001.