HET0016, a selective inhibitor of 20-HETE synthesis, decreases pro-angiogenic factors and inhibits growth of triple negative breast cancer in mice.

A selective inhibitor of 20-HETE synthesis, HET0016, has been reported to inhibit angiogenesis. 20-HETE has been known as a second mitogenic messenger of angiogenesis inducing growth factors. HET0016 effects were analyzed on MDA-MB-231 derived breast cancer in mouse and in vitro cell line.

20-HETE can act as a nonhypoxic regulator of HIF-1alpha in human microvascular endothelial cells.

20-HETE increases the expression of VEGF in human dermal microvascular endothelial cells (ECs). Since VEGF is regulated by hypoxia inducible factor (HIF)-1, we studied whether 20-HETE also upregulates HIF-1alpha using the stable 20-HETE analog 20-hydroxyeicosa-5(Z),14(Z)dienoic acid (WIT003; 1-10 microM) and found that it induced a marked increase in HIF-1alpha protein levels. The increases in VEGF after the addition of WIT003 preceded the changes in HIF-1alpha, and the increases in HIF-1alpha were prevented by a VEGF neutralizing antibody.

Expression of CYP4A1 in U251 human glioma cell induces hyperproliferative phenotype in vitro and rapidly growing tumors in vivo.

Exogenous 20-hydroxyeicosatetraenoic acid (20-HETE) increases the growth of human glioma cells in vitro. However, glioma cells in culture show negligible 20-HETE synthesis. We examined whether inducing the expression of a 20-HETE synthase in a human glioma U251 cell line would increase proliferation.

Role of angiotensin II in retinal leukostasis in the diabetic rat.

To study if the endogenous renin-angiotensin system affects diabetic retinal leukostasis, rats with streptozotocin-induced diabetes were treated with an ACE inhibitor (ramipril), an angiotensin II AT(1) receptor antagonist (losartan) and the Ca channel blocker, (nifedipine). In the diabetic rats, these drug treatments reduced systolic blood pressure by approximately 16 mmHg but did not change blood glucose. After 2 weeks, the rats were examined for retinal leukostasis in vivo with a scanning laser ophthalmoscope (SLO).

Inhibition of vascular endothelial growth factor-associated tyrosine kinase activity with SU5416 blocks sprouting in the microvascular endothelial cell spheroid model of angiogenesis.

The angiogenic vascular endothelial growth factor (VEGF) is believed to play a critical role in endothelial cell proliferation, differentiation, and sprouting. Small molecules that selectively inhibit the VEGF receptor-associated tyrosine kinase activities of Flk-1 (KDR) and Flt-1 have been developed. These agents, a prototype being SU5416, have effects on the proliferation of cultured endothelial cells, constrain angiogenesis in vivo, and have been proposed as antitumor drugs.

Transforming growth factor beta in experimentally detached retina and periretinal membranes.

This study was undertaken to determine whether experimental retinal detachment produces changes in retinal localization of three isoforms of transforming growth factor beta (TGF-beta) and the type II receptor for this protein. Neural retinas of young adult cats were detached from the pigment epithelium. Survival times varied from 3 to 28 days to study the temporal course of TGF-beta localization during retinal degeneration.

Angiotensin II stimulates migration of retinal microvascular pericytes: involvement of TGF-beta and PDGF-BB.

We studied the promigratory effect of angiotensin II (ANG II) on cultured bovine retinal microvascular pericytes. ANG II stimulated migration of pericytes by 86% at 10(-8) M, but this effect was lost at 10(-4) M. Migratory responses were inhibited by the ANG II type 1 (AT(1)) receptor antagonist losartan but not by PD-123319, an AT(2) antagonist.

Cardiac interstitial bradykinin release during ischemia is enhanced by ischemic preconditioning.

Ischemic preconditioning is known to protect the myocardium from ischemia-reperfusion injury. We examined the transmural release of bradykinin during myocardial ischemia and the influence of ischemic preconditioning on bradykinin release during subsequent myocardial ischemia. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery in anesthetized cats.

Role of kinins in chronic heart failure and in the therapeutic effect of ACE inhibitors in kininogen-deficient rats.

Using Brown Norway Katholiek (BNK) rats, which are deficient in kininogen (kinin precursor) due to a mutation in the kininogen gene, we examined the role of endogenous kinins in 1) normal cardiac function; 2) myocardial infarction (MI) caused by coronary artery ligation; 3) cardiac remodeling in the development of heart failure (HF) after MI; and 4) the cardioprotective effect of angiotensin-converting enzyme inhibitors (ACEI) on HF after MI. Two months after MI, rats were randomly treated with vehicle or the ACEI ramipril for 2 mo. Brown Norway rats (BN), which have normal kininogen, were used as controls.

Angiotensin II and retinal pericytes migration.

Angiotensin II (Ang II) appears to participate in the regulation of neovascularization processes in the retina. Migration of perimural cells such as pericytes plays a key role in regulation of angiogenesis. We hypothesize that Ang II stimulates migration of retina pericytes.

Role of endothelial kinins in control of coronary nitric oxide production.

The purpose of the present study was to determine whether interventions that promote kinin production or decrease kinin inactivation affect nitric oxide production in isolated canine coronary microvessels. Accordingly, bradykinin (10[-8] to 10[-5] mol/L), ramiprilat (10[-10] to 10[-8] mol/L), A23187 (10[-8] to 10[-6] mol/L), kallikrein (1 to 20 U/mL), and kininogen (0.5 to 10 microg/mL) were used to stimulate endothelium-dependent nitric oxide production.

Role of kinins in the cardioprotective effect of preconditioning: study of myocardial ischemia/reperfusion injury in B2 kinin receptor knockout mice and kininogen-deficient rats.

Kinins acting on the B2 receptor appear to be involved in the cardioprotective effect of preconditioning on myocardial ischemia/reperfusion injury. We tested the hypothesis that in mice lacking the gene encoding for the B2 kinin receptor (B2 knockout mice; B2-KO) as well as in rats deficient in high-molecular-weight (HMW) kininogen (Brown Norway Katholiek rats; BNK), the cardioprotective effect of preconditioning is diminished or abolished. 129SvEvTac (SV129) mice and Brown Norway rats (BN) served as controls.

Short-term hemodynamic effects of endothelin receptor blockade in dogs with chronic heart failure.

Background: Plasma endothelin levels are increased in heart failure and may contribute to the increased peripheral vasoconstriction that characterizes this disease state. In the present study, we examined the effects of intravenous bosentan, a nonpeptide, competitive endothelin-1 receptor antagonist, on hemodynamics in dogs with chronic heart failure.

Methods And Results: Chronic heart failure was produced in 11 dogs by multiple sequential intracoronary microembolization.

A local kallikrein-kinin system is present in rat hearts.

It has been reported that kinins mediate part of the beneficial cardiac effects induced by treatment with angiotensin-converting enzyme inhibitors in situations such as ischemia-reperfusion injury, myocardial infarction, and cardiac hypertrophy. However, it is not known whether the heart contains an independent kallikrein-kinin system. We measured kallikrein in tissue and in the incubation medium of heart slices.

Effects of long-term monotherapy with enalapril, metoprolol, and digoxin on the progression of left ventricular dysfunction and dilation in dogs with reduced ejection fraction.

Background: Recent clinical trials have suggested that therapy with angiotensin-converting enzyme inhibitors in asymptomatic patients with reduced left ventricular (LV) function can significantly reduce the incidence of congestive heart failure compared with patients receiving placebo. In the present study, we examined the effects of long-term monotherapy with enalapril, metoprolol, and digoxin on the progression of LV systolic dysfunction and LV chamber enlargement in dogs with reduced LV ejection fraction (EF).

Methods And Results: LV dysfunction was produced in 28 dogs by multiple sequential intracoronary microembolizations.

Adrenal kallikrein.

Kallikrein was identified in the adrenal glands of the rat. The enzyme was present in active and inactive forms (n = 9), since preincubation with trypsin increased kininogenase activity from 54.8 +/- 11.

Synthesis of renin by tubulocystic epithelium in autosomal-dominant polycystic kidney disease.

Evidence suggests an important role for the renin-angiotensin system in the pathogenesis of autosomal-dominant polycystic kidney disease (ADPKD). Therefore, we studied the presence of immunoreactive renin in renal biopsies and measured the concentrations of renin in cyst fluids. Normal kidneys and kidneys with renal artery stenosis were used for comparison.

Endothelium-derived relaxing factor inhibits transport and increases cGMP content in cultured mouse cortical collecting duct cells.

Stimulation of the release of endothelium-derived relaxing factor (EDRF) in the kidney has been shown to result in natriuresis without affecting glomerular filtration rate. This may be due to EDRF directly regulating solute transport in the cortical collecting duct (CCD). To test this hypothesis, we measured the effect of bradykinin (Bk) or acetylcholine (Ach) on short-circuit current (Isc; a measure of active transport) in a CCD cell line (M-1), in the presence or absence of cow pulmonary artery endothelial (CPAE) cells.

The kallikrein-kinin system in cardiac tissue.

Kallikrein and minute amounts of kininogen have been found in rat cardiac tissue. The mRNA for kallikrein was also determined by the polymerase chain reaction using KK-specific probe. The existence of an intrinsic kallikrein-kinin system in the heart raises the possibility that the enzyme-peptide system is involved in local regulation of cardiac function and metabolism.

T-kininogenase activity of the rat submandibular gland is predominantly due to the kallikrein-like serine protease antigen gamma.

T-kininogen, the major kininogen in rat plasma, releases Ile-Ser-bradykinin (T-kinin) when incubated with trypsin, but is not a substrate for tissue kallikrein. Enzymes able to release T-kinins from T-kininogen have been found in the rat submandibular gland, but precise identification of these enzymes and their possible relationship to kallikrein-like enzymes has not been established. We studied T-kininogenase activity in fractionated submandibular gland homogenate.

Effect of an angiotensin II and a kinin receptor antagonist on the renal hemodynamic response to captopril.

The role of angiotensin II and kinins on the renal cortical and papillary hemodynamic and on the sodium and water excretory responses to converting enzyme inhibition with captopril was examined in euvolemic Munich-Wistar rats. Cortical and papillary blood flows were measured using a laser Doppler flowmeter. Cortical blood flow increased 28% after blockade of angiotensin II receptors with DuP 753 (2 mg/kg i.

A kallikrein-like enzyme in blood vessels of one-kidney, one clip hypertensive rats.

Active and inactive kallikrein or a kallikrein-like enzyme are found in the aorta, vena cava, and tail artery and veins of the rat. We studied the concentration of vascular kininogenase in rats with one-kidney, one clip renovascular hypertension and in unilaterally nephrectomized normotensive rats. Six weeks after surgery, active and total vascular kininogenase activity (active plus trypsin-activated) was measured.

Renal effects of Fab fragments of kinin antibodies on deoxycorticosterone acetate-salt-treated rats.

The role of the renal kallikrein-kinin system in the regulation of renal function is not completely understood. Intrarenal kinins can influence renal function by acting as paracrine hormones at basolateral, luminal, or both sites in the distal nephron. To examine the role of intrarenal kinins in deoxycorticosterone acetate-salt-treated rats, which have high renal kallikrein, Fab fragments of antibradykinin antibody or DArg[Hyp3Thi5,8DPhe7]bradykinin, a kinin antagonist, were used to block kinins.

Kinins contribute to the contractile effects of rat glandular kallikrein on the isolated rat uterus.

Glandular kallikrein is known to promote contractions of the isolated, estrogenized rat uterus, perhaps independently of kinin formation. The recent availability of kinin receptor antagonists led us to study whether they might affect the oxytocic activity of kallikrein. DArg0-Hyp3-Thi5,8-DPhe7-bradykinin (8.

Glandular kallikrein-like enzyme in adrenal glands.

A kallikrein-like kininogenase was identified in the rat adrenal gland. Most of the enzyme was present in an inactive form, since pre-incubation with trypsin markedly increased kininogenase activity from 54.8 +/- 11.