Superior antiproliferative effects mediated by interferon-α entrapped in liposomes against a newly established human lung cancer cell line

The purpose of this study was to characterize the antiproliferative activity of a recombinant interferon-α (IFN-α) against a newly established human adenocarcinoma cell line (DMS-4C) and to determine whether IFN-α entrapped in multilamellar liposomes had superior antitumor effects compared with free IFN-α. Treatment of DMS-4C cells with 100 U/ml of free IFN-α resulted in 34% cytostasis. IFN-α encapsulated in phosphatidylcholine/phosphatidylserine multilamellar vesicles produced growth inhibition of 67%, which was significantly greater than that produced by free IFN-α or by control liposomes containing only medium combined with free IFN-α. Moreover, kinetic analysis revealed that to produce significant cytolysis, free IFN-α had to be incubated with target cells for at least 24 h, whereas IFN-α encapsulated into liposomes required only 30 min of exposure.