title: Phorbol ester stimulated Cip1 expression in p53-negative leukemic cells.
abstract: In differentiating leukemic cells, cyclin-dependent kinase interacting protein (Cip1) is induced and stimulates a G(1) arrest. TPA treated U937 monoblastoid cells expressed Cip1, hypophosphorylated retinoblastoma protein (Rb), arrested in G(1) and differentiated. PKC-zeta cells are U937 cells that overexpress the zeta isoform and display alterations in endogenous PKC isoform expression. TPA treated PKC-zeta cells undergo apoptosis without differentiating. TPA treated PKC-zeta cells express Cip1 and display substantial hypophosphorylation of Rb but fail to arrest in G(1). Thus, a novel phorbol ester dependent signalling pathway exists in which Cip1 induction is associated with the absence of a G(1) arrest and induction of apoptosis rather than differentiation.
authors: E CAROLINA UNIV,SCH MED,DEPT MED,DIV ENDOCRINOL,GREENVILLE,NC 27858. E CAROLINA UNIV,SCH MED,DEPT IMMUNOL MICROBIOL,GREENVILLE,NC 27858.
authors: J
authors: J
authors: Devente
authors: W
authors: W
authors: Bryant
authors: K
authors: K
authors: Posekany
authors: T
authors: T
authors: Garris
authors: J
authors: J
authors: Chen
authors: J
authors: J
authors: Carey
authors: P
authors: P
authors: Cook
authors: K
authors: K
authors: Ways