Pentameric procyanidins isolated from Theobroma cacao seeds selectively downregulate ErbB2 in human aortic endothelial cells.
Flavonoids isolated from cocoa have biological activities relevant to oxidant defenses, vascular health, tumor suppression, and immune function. The intake of certain dietary flavonoids, along with other dietary substances such as tocopherols, ascorbate, and carotenoids, is epidemiologically associated with a reduced risk of cardiovascular disease. Flavonoids have also been shown to modulate tumor pathology in vitro and in animal models. We took advantage of the conserved sequences found in tyrosine kinases to study the influence of cocoa fractions and controls on gene expression. We report that the pentameric procyanidin (molecular weight of 1442 daltons) fraction isolated from cocoa was a potent inhibitor of tyrosine kinase ErbB2 expression, a receptor important in angiogenesis regulation. Consistent with this primary observation, the cocoa flavonoid fraction also suppressed human aortic endothelial cell (HAEC) growth and decreased expression of two tyrosine kinases responsive to ErbB2 modulation, namely VEGFR-2/KDR and MapK 11/p38beta2. These inhibitory effects were observed when HAECs were treated with the flavonol fraction (molecular weight 280 daltons) isolated from cocoa, which comprise the structural subunits from which the procyanidin flavonoid subclass is biosynthetically constructed. Down-regulation of ErbB2 and inhibition of HAEC growth by cocoa procyanidins may have several downstream implications, including reduced vascular endothelial growth factor (VEGF) activity and angiogenic activity associated with tumor pathology. These results suggest specific dietary flavonoids are capable of selectively inhibiting ErbB2 and therefore may offer important insight into the design of therapeutic agents that target tumors overexpressing ErbB2.
Kenny
Thomas P
TP
Division of Rheumatology, Allergy, and Clinical Immunology, University of California at Davis, Davis, California 95616, USA.
Keen
Carl L
CL
Jones
Paul
P
Kung
Hsing-Jien
HJ
Schmitz
Harold H
HH
Gershwin
M Eric
ME
D000975:Antioxidants / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects; D044946:Biflavonoids; D002099:Cacao; D002392:Catechin / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D048290:Mitogen-Activated Protein Kinase 11; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology; D044945:Proanthocyanidins; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000187:drug effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis / Q000187:drug effects
D000975:Antioxidants; D044946:Biflavonoids; D002392:Catechin; D048290:Mitogen-Activated Protein Kinase 11; D020928:Mitogen-Activated Protein Kinases; D010936:Plant Extracts; D044945:Proanthocyanidins; D018719:Erb-b2 Receptor Tyrosine Kinases; D040301:Vascular Endothelial Growth Factor Receptor-2; C017674:procyanidin