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

Figure 1 Up-regulation of spermine synthase in colorectal cancer cells HCT116 promotes cell proliferation and inhibits apoptosis. A and B: Western blot analysis for spermine synthase (SMS) protein expression levels in FHC, HCT116, SW62, SW480, HT-29 and LoVo cells groups (A), as well as in negative control shRNA (shNC), SMS shRNA (sh-SMS), negative control over-expression vector (OE-NC), and OE-SMS HCT116 cell groups (B); C: MTT assay to detect the viability of cells in shNC, sh-SMS, OE-NC, and OE-SMS HCT116 groups; D: Colony formation assay to assess the colony formation ability of cells in shNC, sh-SMS, OE-NC, and OE-SMS HCT116 groups; E: Flow cytometry analysis of cell apoptosis levels in shNC, sh-SMS, OE-NC, and OE-SMS HCT116 groups. ^aP< 0.05, ^bP < 0.01 vs FHC, shNC; ^dP < 0.01 vs OE-NC; 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.