The protein kinase C agonist PEP005 increases NF-kappaB expression, induces differentiation and increases constitutive chemokine release by primary acute myeloid leukaemia cells

• Published in: British journal of haematology 2009-06, Vol.145 (6), p.761-774
• Main Authors: Olsnes, Astrid Marta, Ersvaer, Elisabeth, Ryningen, Anita, Paulsen, Kristin, Hampson, Peter, Lord, Janet M, Gjertsen, Bjørn Tore, Kristoffersen, Einar Klaeboe, Bruserud, Øystein
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Antineoplastic Agents - therapeutic use; Cell Differentiation; Chemokines - immunology; Diterpenes - therapeutic use; Female; Flow Cytometry; Humans; Leukemia, Myeloid, Acute - drug therapy; Leukemia, Myeloid, Acute - immunology; Leukemia, Myeloid, Acute - metabolism; Male; Middle Aged; NF-kappa B - analysis; NF-kappa B - genetics; NF-kappa B - metabolism; Protein Kinase C - metabolism; RNA Interference; RNA, Small Interfering - pharmacology; Statistics, Nonparametric; Tumor Cells, Cultured
• ISSN: 1365-2141
• DOI: 10.1111/j.1365-2141.2009.07691.x

Acute myeloid leukaemia (AML) cells show constitutive release of several chemokines that occurs in three major clusters: (I) chemokine (C-C motif) ligand (CCL)2-4/chemokine (C-X-C motif) ligand (CXCL)1/8, (II) CCL5/CXCL9-11 and (III) CCL13/17/22/24/CXCL5. Ingenol-3-angelate (PEP005) is an activator of protein kinase C and has antileukaemic and immunostimulatory effects in AML. We investigated primary AML cells derived from 35 unselected patients and determined that PEP005 caused a dose-dependent increase in the release of chemokines from clusters I and II, including several T cell chemotactic chemokines. The release of granulocyte-macrophage colony-stimulating factor and hepatocyte growth factor was also increased. CCL2-4/CXCL1/8 release correlated with nuclear factor (NF)-kappaB expression in untreated AML cells, and PEP005-induced chemokine production was associated with further increases in the expression of the NF-kappaB subunits p50, p52 and p65. Increased DNA binding of NF-kappaB was observed during exposure to PEP005, and the specific NF-kappaB inhibitor BMS-345541 reduced constitutive chemokine release even in the presence of PEP005. Finally, PEP005 decreased expression of stem cell markers (CD117, CXCR4) and increased lineage-associated CD11b and CD14 expression. To conclude, PEP005 has a unique functional pharmacological profile in human AML. Previous studies have described proapoptotic and T cell stimulatory effects and the present study describes additional T cell chemotactic and differentiation-inducing effects.