Lack of p21(waf1) and p27(kip1) protein induction by interferon-α2a in human melanoma cell lines

The ability of human recombinant interferon-α2a (IFNα2a) to induce the expression of cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1) consequent to signal transducers and activators of transcription (STAT) protein activation was investigated in six human melanoma cell lines with different susceptibilities to the antiproliferative effect of the cytokine. All the cell lines expressed IFNα and IFNα/β receptors. Exposure for 24 h to IFNα2a markedly enhanced the nuclear expression of STAT1 and STAT2 proteins in all the cell lines. However, no induction of p21(waf1) or p27(kip1) was consistently observed. Overall, results from the study suggest that the induction of such cyclin-dependent kinase inhibitors is not a major mechanism for the antiproliferative effect of IFNα2a, at least in human melanoma cell lines.