Rottlerin inhibits P2X(7) receptor-stimulated phospholipase D activity in chronic lymphocytic leukaemia B-lymphocytes

• Published in: Immunology and cell biology Vol. 85; no. 1; p. 68
• Main Authors: Shemon, Anne N, Sluyter, Ronald, Wiley, James S
• Format: Journal Article
• Language: English
• Published: United States 01.01.2007
• Subjects: Acetophenones - pharmacology; Adenosine Triphosphate - pharmacology; B-Lymphocytes - drug effects; B-Lymphocytes - enzymology; Benzopyrans - pharmacology; Cell Line, Tumor; Dose-Response Relationship, Drug; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Leukemic; Humans; Leukemia, Lymphocytic, Chronic, B-Cell - enzymology; Phospholipase D - metabolism; Polymorphism, Genetic; Protein Isoforms - antagonists & inhibitors; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - genetics; Protein Kinase C - metabolism; Receptors, Purinergic P2 - metabolism; Receptors, Purinergic P2X7; Rubidium - metabolism
• ISSN: 0818-9641
• DOI: 10.1038/sj.icb.7100005

Phospholipase D (PLD) is a ubiquitous enzyme that can be activated by extracellular adenosine 5'-triphosphate (ATP) or phorbol 12-myristate 13-acetate (PMA) in B-lymphocytes from subjects with chronic lymphocytic leukaemia (CLL). In this study, ATP- but not PMA-induced PLD stimulation in CLL B-lymphocytes was abolished in the presence of an anti-P2X(7) receptor monoclonal antibody, as well as in B-lymphocytes from CLL subjects homozygous for the Glu(496) to Ala loss-of-function P2X(7) polymorphism. Rottlerin, an inhibitor of novel protein kinase C (PKC) isoforms, but not GF 109203X, an inhibitor of conventional PKC isoforms, impaired the ATP-stimulated PLD activity in CLL B-lymphocytes. In contrast, both inhibitors impaired PLD activity stimulated by PMA, a known mediator of PKC activation. The inhibition of P2X(7)-stimulated PLD activity by rottlerin was attributed to a target downstream of P2X(7) activation, as the ATP-mediated (86)Rb(+) efflux from CLL B-lymphocytes was not altered in the presence of rottlerin. Our results indicate a possible role for novel PKC isoforms in the regulation of P2X(7)-mediated PLD activity.