Induction of apoptotic cell death in non-melanoma skin cancer by interferon-alpha.

Interferon-alpha (IFN-alpha) is a cytokine that is effective in the treatment of a variety of cancers, including non-melanoma skin cancers. The biologic responses of cells to IFN-alpha are pleiotropic and include growth suppression and immunomodulation. The potential direct effects of IFN-alpha on tumor cell populations are incompletely characterized. Our findings indicate that IFN-alpha can directly induce apoptosis (programmed cell death) in sensitive squamous cell skin cancer cell lines. Cell lines resistant to the cytotoxic effects of IFN-alpha showed no evidence of apoptosis induction. Transfection of IFN-alpha-sensitive cell lines with a bcl-2 expression vector conferred partial resistance to cell death induction by IFN-alpha. Our results indicate that the clinical efficacy of IFN-alpha may, in part, be related to the ability of this cytokine to induce apoptosis.