Improvement of 5-fluorouracil chemosensitivity in colorectal cancer cells by siRNA-mediated silencing of STAT6 oncogene

Abstract

Objectives: Colorectal cancer (CRC) remains a major health concern worldwide due to its high incidence, mortality rate, and resistance to conventional treatments. The discovery of new targets for cancer therapy is essential to improve the survival of CRC patients. Here, this study aims to present a finding that identifies the STAT6 oncogene as a potent therapeutic target for CRC.

Materials and methods: HT-29 CRC cells were transfected with STAT6 siRNA and treated with 5-fluorouracil (5-FU) alone and combined. Then, to evaluate cellular proliferation and apoptosis percentage, MTT assay and annexin V/PI staining were carried out, respectively. Moreover, the migration ability of HT-29 cells was followed using a wound-healing assay, and a colony formation assay was performed to explore cell stemness features. Gene expression was quantified via qRT-PCR. Afterward, functional enrichment analysis was used to learn in-depth about the STAT6 co-expressed genes and the pathways to which they belong.

Results: Our study shows that silencing STAT6 with small interfering RNA (siRNA) enhances the chemosensitivity of CRC cells to 5-FU, a commonly used chemotherapy drug, by inducing apoptosis, reducing proliferation, and inhibiting metastasis. These results suggest that combining 5-FU with STAT6-siRNA could provide a promising strategy for CRC treatment.

Conclusion: Our study sheds light on the potential of STAT6 as a druggable target for CRC cancers, the findings offer hope for more effective treatments for CRC patients, especially those with advanced stages that are resistant to conventional therapies.

Keywords: 5-Fluorouracil; Chemosensitivity; Colorectal cancer; STAT6; siRNA.

Figure 1

Investigation of STAT6 expression in the CRC cell lines

Figure 2

Impact of STAT6 siRNA at various periods and dosages on STAT6 expression in HT-29 cell line

Figure 3.

Effect of STAT6-siRNA separate and in combination with 5-FU on cell proliferation in HT-29 cell line

Figure 4

A) Annexin V-FITC/PI test revealed that STAT6-siRNA-transfected cells that were treated with 5-FU had higher apoptotic activity than STAT6-siRNA-transfected cells with no 5-FU treatment. B) The combined group qRT-PCR results showed a significantly higher expression of caspase9 and Bax but a significantly lower expression of Bcl2 (P<0.05, P< 0.01, P<0 .001, P<0.0001).

Figure 5

Effects of STAT6-siRNA, 5-FU treatment and combined therapy on HT-29 cell cycle distribution

Figure 6

Effects of STAT6-siRNA, 5-FU treatment and combined therapy on HT-29 cell migration

Figure 7

STAT6-siRNA suppression effect combined with 5-FU treatment on colony formation of HT-29 cells

Figure 8

The genes that are co-expressed with STAT6

Figure 9

The genes essential involvement in the various pathways and displaying the pathways associated with the genes that are co-expressed