GSK484, an inhibitor of peptidyl arginine deiminase 4, increases the radiosensitivity of colorectal cancer and inhibits neutrophil extracellular traps

PAD4 inhibitor GSK484 promotes the radiosensitivity of CRC and inhibits NET formation in vivo and in vitro.

Reverse transcriptase quantitative polymerase chain reaction and western blotting were used to measure PAD4 expression in CRC tissues and cells. GSK484, an inhibitor of PAD4, was investigated in the following functional assays in vitro: western blotting, clonogenic survival, colony formation, TUNEL, flow cytometry and transwell assays. Nude mouse xenograft models were applied to evaluate the effect of GSK484 on tumor growth in CRC in vivo. The formation of NETs influenced by GSK484 was also investigated.

We showed upregulation of PAD4 mRNA and protein in CRC tissues and cells. High expression of PAD4 was related to a poor prognosis in CRC patients. GSK484 treatment promoted the radiosensitivity of CRC cells and induced cell death by promoting DNA double-strand breaks. Rescue experiments further verified that GSK484 inhibited the effects of PAD4 overexpression in irradiated CRC cells. Moreover, GSK484 injection strengthened the radiosensitivity of CRC and inhibited NET formation in vivo. Conclusions: PAD4 inhibitor GSK484 promotes the radiosensitivity of CRC and inhibits NET formation in vivo and in vitro.