Induction of apoptotic cell death by IFN beta on HPV-16 transformed human keratinocytes

Apoptosis, or 'programmed cell death' is a process of general biological re levance with implications in several physiological and pathological conditi ons of the skin. However, little is known about its induction in keratinocy tes by regulator agents. In this work we demonstrate that IFN beta, but not IFN alpha, selectively induces programmed cell death in HPK-Ia cells, a li ne derived from human keratinocytes transformed with HPV-16 DNA. This IFN b eta-triggered apoptosis is strictly dependent on a serum-induced partially differentiated phenotype; it occurs through the activation of a check point in the early 'S' phase, where the cells are arrested and eventually driven to apoptosis. These data indicate that apoptosis may be induced in keratin ocytes by a regulator agent combined with a differentiating stimulus. (C) 1 999 Elsevier Science B.V. All rights reserved.