Effects of IFI16 overexpression on the growth and doxorubicin sensitivity of head and neck squamous cell carcinoma-derived cell lines

BACKGROUND: In a previous analysis of head and neck squamous cell carcinomas (HNSCCs), we showed that the levels of the interferon-inducible protein IFI16 inversely correlate with cancer grade. In this study, we further evaluate the molecular role of IFI16 in the development of HNSCCs. METHODS: The effect of IFI16 expression was evaluated by its retroviral restoration in an IFI16-negative HNSCC-derived cell line, HNO136. Growth rate and soft agar colony formation were evaluated. The effect of IFI16 restoration in cells exposed to doxorubicin was also analyzed. RESULTS: IFI16 restoration resulted in the inhibition of both cell growth and in vitro transforming activity and increased doxorubicin-induced cell death by accumulating the cells at the G2/M phase. CONCLUSION: In agreement with our previous in vivo data, IFI16 appears to be involved in maintaining the normal growth of epithelial cells, whereas its downregulation may contribute to uncontrolled cell proliferation and tumorigenesis.