Enhancing the radiosensitivity of colorectal cancer cells by reducing spermine synthase through promoting autophagy and DNA damage

Figure 3 Knockdown of spermine synthase enhances the radiosensitivity of HCT116 cells by advancing DNA damage. A-C: Comet assay for assessing DNA damage levels in HCT116 cells of the negative control shRNA (shNC), shNC + IR, spermine synthase shRNA (sh-SMS), and sh-SMS + IR groups (A), and analysis of comet tail DNA levels (B) and comet tail moments (C); D and E: Western blot analysis of γH2AX, p-γH2AX, ATR, p-ATR, and P53 protein levels in HCT116 cells of the shNC group, shNC + IR group, sh-SMS group, and sh-SMS + IR group. ^bP < 0,01 vs shNC, ^dP < 0.01 vs shNC + IR, ^fP < 0.01 vs sh-SMS; SMS: Spermine synthase; sh-SMS: Spermine synthase shRNA; shNC: Negative control shRNA; OE-SMS: Spermine synthase over-expression vector; OE-NC: Negative control over-expression vector.