10-Hydroxy-2-decenoic Acid, a Major Fatty Acid from Royal Jelly, Inhibits VEGF-Induced Angiogenesis in Human Umbilical Vein Endothelial Cells
10-Hydroxy-2-decenoic Acid, a Major Fatty Acid from Royal Jelly, Inhibits VEGF-induced Angiogenesis in Human Umbilical Vein Endothelial Cells
Hiroshi Izuta 0
Yuichi Chikaraishi 0
Masamitsu Shimazawa 0
Satoshi Mishima 1
Hideaki Hara 0
0 Department of Biofunctional Evaluation, Laboratory of Molecular Pharmacology, Gifu Pharmaceutical University , 5-6-1 Mitahora-higashi, Gifu 502-8585 , Japan
1 Nagaragawa Research Center, API Co. Ltd , 692-3 Nagara, Yamasaki, Gifu 502-0071 , Japan
Vascular endothelial growth factor (VEGF) is reported to be a potent pro-angiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. Royal jelly (RJ) is a honeybee product containing various proteins, sugars, lipids, vitamins and free amino acids. 10-Hydroxy-2-decenoic acid (10HDA), a major fatty acid component of RJ, is known to have various pharmacological effects; its antitumor activity being especially noteworthy. However, the mechanism underlying this effect is unclear. We examined the effect of 10HDA on VEGFinduced proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs). Our findings showed that, 10HDA at 20 mM or more significantly inhibited such proliferation, migration and tube formation. Similarly, 10 mM GM6001, a matrix metalloprotease inhibitor, prevented VEGF-induced migration and tube formation. These findings indicate that 10HDA exerts an inhibitory effect on VEGF-induced angiogenesis, partly by inhibiting both cell proliferation and migration. Further experiments will be needed to clarify the detailed mechanism.
HUVECs - migration - proliferation - tube formation
Introduction
Angiogenesis, the formation of new blood vessels from
the pre-existing vasculature, is a highly regulated process
that is essential for the development of multicellular
organisms (
1,2
). In the adult, angiogenesis is normally
restricted and is predominantly associated with female
reproductive functions and wound healing (
3,4
). Vascular
endothelial growth factor (VEGF) is a key regulator of
normal and pathological angiogenesis (
5?7
). At the
cellular level, VEGF stimulation drives multiple responses,
including endothelial cell proliferation, migration,
survival and permeability (
8
). Loss of regulation of
angiogenesis, resulting in uncontrolled and excessive
neovascularization, contributes to the development of
many pathologies, including retinopathies, rheumatoid
arthritis and tumor growth (
9,10
).
Royal jelly (RJ), the exclusive food of the larva of
the queen honeybee (Apis mellifera), is secreted from the
hypopharyngeal and mandibular glands of the worker
honeybees mainly between the sixth and twelfth days of
their life (
11
). RJ has been demonstrated to possess
several pharmacological activities in experimental
animals, including vasodilator and hypotensive activities
(
12
), growth rate increasing activity (
13
), a disinfectant
action (
14
), antitumor activity (
15?17
),
antihypercholesterolemic activity (
18
) and anti-inflammatory activity
(
19
). Chemical composition analysis has shown that RJ
consists mainly of proteins, sugars, lipids, vitamins and
free amino acids (
20,21
). 10HDA, a major fatty acid
component of RJ, has many pharmacological activities,
such as antitumor activity (22), size- and
lipogenesisinhibiting activity toward the hamster ear sebaceous
gland (
23
), collagen production promoting activity (
24
)
and antibiotic activity (
25
). As a consequence, RJ is
widely used in commercial medical products, health foods
and cosmetics in many countries. However, the
mechanisms underlying these activities of RJ, especially the
antitumor activity, remain unknown.
Matrix metalloproteinase (MMP) is required for
migration and invasion by normal and tumor cells. We initially
utilized the MMP inhibitor GM6001 to assess the effect
of MMP inhibitors on thymocyte development. GM6001,
a hydroxylamine-based inhibitor which inhibits many
MMP with a Ki in the low nanomolar range, has been
reported to reduce the migration of many kinds of cells
(
26
). We used GM6001 as a positive control in the
present study.
The purpose here was to evaluate the functional role of
10HDA on human pathology. A number of compounds,
including valproic acid (
27
), sodium butyrate (
28
) and
isomers of conjugated linoleic acid (
29
), are known to be
angiogenesis inhibitors. Here, we examined the effects of
10HDA on VEGF-induced angiogenesis in human
umbilical vein endothelial cells (HUVECs).
Methods
Cells and Chemicals
HUVECs, fibroblast cells, endothelial cell basal medium
(HuMedia-EB2), fetal bovine serum (FBS), gentamycin,
amphotericin B, endothelial growth factors (hEGF,
hydrocortisone, hFGF-B and heparin), VEGF, mouse
antihuman CD31 antibody, goat antimouse IgG alkaline
phosphatase-conjugated antibody,
5-bromo-4-chloro3-indolyl phosphate/nitro blue tetrazolium (BCIP/NBT)
and angiogenesis growth medium were purchased from
Kur (...truncated)