Role of interferon alpha-inducible protein 6 in modulating the proliferation, apoptosis and senescence of oesophageal squamous cell carcinoma cells.

Oesophageal cancer is one of the most malignant tumors worldwide. Dysfunction of interferon alpha-inducible protein 6 (IFI6) has been implicated in numerous human diseases, including cancer. We performed the study to investigate the function and potential molecular pathways of IFI6 in oesophageal squamous cell carcinoma (ESCC) cells. IFI6 expression was analysed using databases-derived data and paraffin-embedded tissue samples. CCK-8-based analyses and EdU staining, colony formation, β-galactosidase staining and Annexin V/PI double-staining assays were used to determine the influence of IFI6 on cell growth, senescence and apoptosis. Tumor growth in vivo was investigated in mouse xenograft models. RNA sequencing (RNA-seq) was performed to identify the transcripts and pathways affected by IFI6. The results showed that IFI6 expression was elevated in ESCC and correlated with poor clinical prognosis (P<0.05). IFI6 was overexpressed and silenced in TE-1 and TE-10 cells using lentiviruses. Upregulation of IFI6 promoted cell growth both in vitro and in vivo, whereas downregulation induced opposite effects. IFI6 overexpression inhibited cell senescence and apoptosis but did not influence cell cycle progression, while IFI6 downregulation increased cell senescence and apoptosis. RNA-seq revealed that 3 mRNAs (EPHA5, CLIP1 and GTF2F2) were consistently associated with both IFI6 overexpression and silencing. IFI6 appeared to modulate TE-1 cells via complex mechanisms. In conclusion, IFI6 plays a positive role in the proliferation of ESCC cells both in vitro and in vivo, which could be a novel therapeutic target for treating ESCC.