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

by Selleckchem | Jun 30 2023

Introduction: Colorectal cancer (CRC) is the third most common malignancy and a major cause of cancer-related deaths. Peptidyl arginine deiminase 4 (PAD4 or PADI4) is expressed in neutrophils that, when activated, can drive the formation of neutrophil extracellular traps (NETs). PAD4 has been found to be upregulated in CRC patients and to predict a poor prognosis. This study is aimed at exploring the role of PAD4 inhibitor (GSK484) in NET formation and radioresistance in CRC.

Methods: 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.

Results: 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.

Comments:

This study aimed to investigate the role of the PAD4 inhibitor GSK484 in neutrophil extracellular trap (NET) formation and radioresistance in colorectal cancer (CRC). PAD4 is an enzyme expressed in neutrophils that can drive the formation of NETs when activated. Previous research has found that PAD4 is upregulated in CRC patients and is associated with a poor prognosis.

The researchers employed several methods to examine the effects of GSK484 on CRC. They measured PAD4 expression in CRC tissues and cells using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and western blotting. They found increased levels of PAD4 mRNA and protein in CRC tissues and cells. Furthermore, higher expression of PAD4 was associated with a poorer prognosis in CRC patients.

In vitro functional assays were conducted to investigate the effects of GSK484 on CRC cells. The researchers utilized techniques such as western blotting, clonogenic survival assays, colony formation assays, TUNEL assays, flow cytometry, and transwell assays. GSK484 treatment was found to enhance the radiosensitivity of CRC cells and induce cell death by promoting DNA double-strand breaks. Additional rescue experiments confirmed that GSK484 could counteract the effects of PAD4 overexpression in irradiated CRC cells.

To evaluate the effect of GSK484 in vivo, the researchers used nude mouse xenograft models. They observed that GSK484 treatment inhibited tumor growth in CRC and enhanced radiosensitivity. Additionally, GSK484 administration was found to suppress NET formation in vivo.

In conclusion, the findings of this study suggest that the PAD4 inhibitor GSK484 promotes radiosensitivity in CRC and inhibits NET formation both in vitro and in vivo. These results highlight the potential of PAD4 inhibition as a therapeutic strategy for improving treatment outcomes in CRC.