Interferon-Alpha Inhibits Proliferation and Induces Apoptosis of Merkel Cell Carcinoma In Vitro

Merkel cell carcinoma is a tumor with aggressive biological behavior and limited response to chemotherapy. The present study investigated the effect of interferon (IFN)-α on growth and apoptosis of Merkel carcinoma cells in vitro. Proliferation of MCC-1 cell line was reduced dose-dependently by IFN-α and diminished when higher IFN-α concentrations were used. Additionally, IFN-α potently decreased DNA-synthesis and Ki67/MIB-1 proliferation index of MCC-1 cultures. Furthermore, IFN-α induced dose-dependently apoptosis of MCC-1 cells as shown by caspase-3 activation, and detection of apoptotic DNA strand breaks and fragmented nuclei. These findings suggest that IFN-α may have antitumor activity against Merkel cell carcinoma.