Activation of PKC-ε counteracts maturation and apoptosis of HL-60 myeloid leukemic cells in response to TNF family members.
Protein kinase C (PKC)-epsilon, a component of the serine/threonine PKC family, has been shown to influence the survival and differentiation pathways of normal hematopoietic cells. Here, we have modulated the activity of PKC-epsilon with specific small molecule activator or inhibitor peptides. PKC-epsilon inhibitor and activator peptides showed modest effects on HL-60 maturation when added alone, but PKC-epsilon activator peptide significantly counteracted the pro-maturative activity of tumor necrosis factor (TNF)-alpha towards the monocytic/macrophagic lineage, as evaluated in terms of CD14 surface expression and morphological analyses. Moreover, while PKC-epsilon inhibitor peptide showed a reproducible increase of TNF-related apoptosis inducing ligand (TRAIL)-induced apoptosis, PKC-epsilon activator peptide potently counteracted the pro-apoptotic activity of TRAIL. Taken together, the anti-maturative and anti-apoptotic activities of PKC-epsilon envision a potentially important proleukemic role of this PKC family member.
Department of Morphology and Embryology, University of Ferrara, Italy. arianna.gonelli@unife.it
A
A
Gonelli
D
D
Milani
E
E
Rimondi
R
R
Voltan
V
V
Grill
C
C
Celeghini
D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D004789:Enzyme Activation; D018922:HL-60 Cells; D006801:Humans; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha; D051744:Protein Kinase C-epsilon