IL-21 silencing inhibits the proliferation, growth, and migration of colorectal cancer cells via suppressing phosphorylation of ERK1/2 and STAT3.

BACKGROUND

This study aimed to elucidate the proliferative and migratory roles of interleukin-21 (IL-21) in HCT-116 and HT-29 colorectal cancer cells using a loss-of-function gene approach.

METHODS

The short hairpin ribonucleic acid (shRNA)- and short interfering ribonucleic acid (siRNA)-mediated approaches were used to achieve specific gene silencing in both cell lines. The downstream experiments, including gene silencing efficiency, were then assessed using Western blotting, microscopy, the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, the transwell migration assay, cell cycle analysis, the clonogenic assay, and the wound healing assay.

RESULTS

Our results revealed that silencing the IL-21 gene significantly suppressed the viability and proliferation of HCT-116 and HT-29 cells. Although IL-21 gene silencing did not induce cell cycle arrest in either cell line, the reduced expression of proliferating cell nuclear antigen (PCNA) upon gene silencing aligned with the proliferation assay results. Additionally, the migration of HCT-116 and HT-29 cells was markedly attenuated upon gene silencing. The restoration of E-cadherin expression in IL-21-silenced cell lines, compared to control cells, indicated decreased receptiveness to epithelial-to-mesenchymal transition (EMT) initiation. Furthermore, IL-21 signalling was found to promote the proliferation and migration of colorectal cancer cells by suppressing the activation and phosphorylation of ERK1/2 and STAT3.

CONCLUSION

The pro-tumourigenic properties of IL-21 could serve as a biomarker of tumour aggressiveness in colorectal cancer and provide insights for the development of advanced cancer therapies.