Diltiazem and glibenclamide are commonly used hypotensive and antidiabetic drugs. This study reports the discovery of the potential antitumor and antimetastatic effects of these two drugs using a structural dynamics-driven virtual screening targeting urokinase receptor (uPAR). Owing to uPAR's high flexibility, currently resolved crystal structures of uPAR, all in ligand-bound states, provide limited representations of its physiological conformation. To improve the accuracy of screening, we performed a long-timescale molecular dynamics simulation and obtained the representative conformations of apo-uPAR as the targets for our screening. Experimentally, we demonstrated that diltiazem and glibenclamide bound uPAR with KD values in the micromolar range. In addition, both compounds effectively suppressed tumor growth and metastasis in a uPAR-dependent manner in vitro and in vivo. This work not only provides two potent uPAR inhibitors but also reports a proof-of-concept study on the potential off-label antitumor and antimetastatic uses of diltiazem and glibenclamide.

The aim of the present study was to investigate the antiatherosclerotic effect of active principle (FIIc) isolated from aqueous fruit pulp extract of Eugenia jambolana. Crude aqueous extract of E. jambolana was subjected to purification using chromatographic techniques which yielded purified active compound (FIIc). Purity of FIIc was tested by HPLC. Phytochemical investigation of FIIc by NMR, IR, and UV spectra showed that the purified compound is α-hydroxy succinamic acid. The streptozotocin- (STZ-) induced diabetic rats were fed atherosclerotic (Ath) diet containing 1.5 mL olive oil containing 8 mg (3, 20,000 IU) vitamin D(2) and 40 mg cholesterol for 5 consecutive days. The STZ-induced diabetic rats receiving Ath diet were orally administered FIIc at doses of 10, 15, and 20 mg/kg, and results were compared with reference drug, that is, glibenclamide (600 μg/mg) and healthy control. 30-day treatment with FIIc resulted in significant (P < .001) improvement in blood glucose, serum lipid profile, apolipoproteins (Apo A(1) and apoB(100)), and endothelial dysfunction parameters. Histomorphological studies also confirmed biochemical findings. Our results showed that FIIc has protective effect on hyperglycemia-induced atherosclerosis.

Although maternal-fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas. Maternal cholesterol may enter fetal circulation by traversing syncytiotrophoblast and endothelial layers of the placenta. We hypothesized that endothelial cells (ECs) of the fetoplacental vasculature display a high and tightly regulated capacity for cholesterol release. Using ECs isolated from human term placenta (HPECs), we investigated cholesterol release capacity and examined transporters involved in cholesterol efflux pathways controlled by liver-X-receptors (LXRs). HPECs demonstrated 2.5-fold higher cholesterol release to lipid-free apolipoprotein (apo)A-I than human umbilical vein ECs (HUVECs), whereas both cell types showed similar cholesterol efflux to high-density lipoproteins (HDLs). Interestingly, treatment of HPECs with LXR activators increased cholesterol efflux to both types of acceptors, whereas no such response could be observed for HUVECs. In line with enhanced cholesterol efflux, LXR activation in HPECs increased expression of ATP-binding cassette transporters ABCA1 and ABCG1, while not altering expression of ABCG4 and scavenger receptor class B type I (SR-BI). Inhibition of ABCA1 or silencing of ABCG1 decreased cholesterol efflux to apoA-I (-70%) and HDL(3) (-57%), respectively. Immunohistochemistry localized both transporters predominantly to the apical membranes of placental ECs in situ. Thus, ECs of human term placenta exhibit unique, efficient and LXR-regulated cholesterol efflux mechanisms. We propose a sequential pathway mediated by ABCA1 and ABCG1, respectively, by which HPECs participate in forming mature HDL in the fetal blood.

Thiazolidinediones are antidiabetic agents that decrease insulin resistance. Emerging evidence indicates that they present beneficial effects for the vasculature beyond glycemic control. The aim of this open-label observational study was to determine the effect of the thiazolidinedione rosiglitazone on novel cardiovascular risk factors, namely, lipoprotein(a) [Lp(a)], C-reactive protein (CRP), homocysteine, and fibrinogen in patients with type 2 diabetes and hypertension. A total of 40 type 2 diabetic patients already on treatment with 15 mg of glibenclamide daily and with poorly controlled or newly diagnosed hypertension were included in the study. Twenty of them received 4 mg of rosiglitazone daily as added-on therapy, whereas the rest remained on the preexisting antidiabetic treatment for 26 weeks. At baseline and the end of the study, subjects gave blood tests for the determination of Lp(a), CRP, homocysteine, fibrinogen, serum lipids, apolipoprotein (apo) A-I, and apo B. At the end of the study, rosiglitazone treatment was associated with significant reductions in Lp(a) (10.5 [8.9-54.1] to 9.8 [8.0-42.0] mg/dL, P<.05) and CRP levels (0.33 [0.07-2.05] to 0.25 [0.05-1.84] mg/dL, P<.05) vs baseline. Homocysteine levels were not affected but plasma fibrinogen presented a significant increase (303.5+/-75.1 to 387.5+/-70.4 mg/dL, P<.01) with rosiglitazone. Although no significant changes were observed in the rosiglitazone group for triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein (LDL) cholesterol, both apo A-I and apo B presented small significant reductions and the LDL-apo B ratio was significantly increased. None of the above parameters were changed in the control group. In conclusion, rosiglitazone treatment had a beneficial impact on Lp(a), CRP, and LDL particles' lipid content in type 2 diabetic hypertensive patients but not on homocysteine and fibrinogen. The overall effect of rosiglitazone on cardiovascular risk factors seems positive but must be further evaluated.

Regulation of gene expression of ATP-binding cassette transporter (ABC)A1 and ABCG1 by liver X receptor/retinoid X receptor (LXR/RXR) ligands was investigated in the human intestinal cell line CaCo-2. Neither the RXR ligand, 9-cis retinoic acid, nor the natural LXR ligand 22-hydroxycholesterol alone altered ABCA1 mRNA levels. When added together, ABCA1 and ABCG1 mRNA levels were increased 3- and 7-fold, respectively. T0901317, a synthetic non-sterol LXR agonist, increased ABCA1 and ABCG1 gene expression 11- and 6-fold, respectively. ABCA1 mass was increased by LXR/RXR activation. T0901317 or 9-cis retinoic acid and 22-hydroxycholesterol increased cholesterol efflux from basolateral but not apical membranes. Cholesterol efflux was increased by the LXR/RXR ligands to apolipoprotein (apo)A-I or HDL but not to taurocholate/phosphatidylcholine micelles. Actinomycin D prevented the increase in ABCA1 and ABCG1 mRNA levels and the increase in cholesterol efflux induced by the ligands. Glyburide, an inhibitor of ABCA1 activity, attenuated the increase in basolateral cholesterol efflux induced by T0901317. LXR/RXR activation decreased the esterification and secretion of cholesterol esters derived from plasma membranes. Thus, in CaCo-2 cells, LXR/RXR activation increases gene expression of ABCA1 and ABCG1 and the basolateral efflux of cholesterol, suggesting that ABCA1 plays an important role in intestinal HDL production and cholesterol absorption.

A unique property of the extracellular matrix of J774 and THP-1 cells has been identified, which contributes to the ability of these cells to promote cholesterol efflux. We demonstrate high level apolipoprotein (apo) A-I binding to macrophage cells (THP-1 and J774) and to their extracellular matrix (ECM). However, high level apoA-I binding is not observed on fibroblasts, HepG2 cells, or U937 cells (a macrophage cell line that does not efflux cholesterol to apoA-I or bind apoA-I on their respective ECM). Binding to the ECM of THP-1 or J774 macrophages depends on the presence of apoA-I C-terminal helices and is markedly reduced with a mutant lacking residues 187-243 (apoA-I Delta(187-243)), suggesting that the hydrophobic C terminus forms a hydrophobic interaction with the ECM. ApoA-I binding is lost upon trypsin treatment or with Triton X-100, a preparation method that de-lipidates the ECM. However, binding is recovered with re-lipidation, and is preserved with ECM prepared using cytochalasin B, which conserves the endogenous phospholipid levels of the ECM. We also demonstrate that specific cholesterol efflux to apoA-I is much reduced in cells released from their native ECM, but fully restored when ECM-depleted cells are added back to ECM in the presence of apoA-I. The apoA-I-mediated efflux is deficient in plated or suspension U937 macrophages, but is restored to high levels when the suspension U937 cells are reconstituted with the ECM of J774 cells. The ECM-dependent activity was much reduced in the presence of glyburide, indicating participation of ABCA1 (ATP-binding cassette transporter 1) in the efflux mechanism. These studies establish a novel binding site for apoA-I on the macrophage ECM that may function together with ABCA1 in promoting cholesterol efflux.

Smooth muscle and endothelial cells in vivo are quiescent yet exposed to high levels of lipoprotein lipids. Phospholipid (PL) and free cholesterol (FC) efflux maintain homeostasis. Smooth muscle cells (SMC) expressed high levels of ABC-1 transporter mRNA, and glyburide-dependent PL and FC efflux to apolipoprotein A-1 (apo A-1), the major protein of high-density lipoprotein. FC efflux was inhibited by vanadate and okadaic acid, while PL efflux was not. Phosphatidylcholine was the major PL transferred by both cell types. Stimulation of phosphatidylserine efflux, redistributed within the membrane by this transporter, was only minimally increased. Umbilical vein and aortic endothelial cells expressed little ABC-1 mRNA, nor did these cells promote either PL or FC efflux in response to the presence of apo A-1. To investigate the mechanism of ABC-1-dependent lipid efflux from these cells, apo A-1 was preincubated in the presence of unlabeled SMC or fibroblasts, and the conditioned medium was then transferred to endothelial cells. This medium catalyzed the efflux of FC but not of PL from endothelial cells. Such FC efflux was resistant to glyburide but inhibited by okadaic acid and vanadate. The data suggest that ABC-1-dependent PL efflux precedes FC efflux to apo A-1 and that the complex of apo A-1 and PL is a much better acceptor of FC than apo A-1 itself. Inhibition of FC but not PL efflux by vanadate and okadaic acid suggests these transfers involve different mechanisms.

Plasma lipids and VLDL and HDL composition were studied in a control group of 20 non diabetic subjects and in 31 male middle-age patients with non-insulin dependent diabetes treated by oral hypoglycemic agent glibenclamide and a weight maintaining diet. Data for the diabetics were separated based on haemoglobin A1c of less or greater than 7%. VLDL composition abnormalities were more frequent in the diabetic patients with HbA1c of > 7%. VLDL-cholesterol, VLDL-triglycerides and VLDL-phospholipids were high in all diabetics whereas VLDL-apo B increased only in diabetics with HbA1c > 7%. Apo CII and apo CIII levels and also apo CII/apo CIII ratio were also reduced in the diabetic patients with HbA1c levels of more than 7%. Increases in the apo E and apo E/apo C ratio were also seen in the more hyperglycemic diabetics with HbA1c levels > 7%. In contrast apo CII and apo CIII levels and also Apo CII/Apo CIII ratio remained unaltered in diabetic patients with less than 7% HbA1c levels. In these patients increases in the apo E levels were found while the apo E/apo C ratio remained unaltered. All diabetic patients showed increases in HDL-triglycerides and triglyceride/total cholesterol ratio with respect to control. Decreases in HDL-apo AI were also seen in both groups of diabetics, but the HDL-apo AI/HDL-apo AII ratio did not differ from control.

In this study, plasma lipids and VLDL composition were measured in 22 middle aged male patients with non-insulin dependent diabetes and compared with 15 non-diabetic controls. Data for the diabetics were differentiated on the basis of hemoglobin A1c levels of less than or greater than 7%. Compositional abnormalities of VLDL were more frequent in the diabetic patients with HbA1c of > 7%. VLDL-cholesterol, triglycerides and phospholipids were elevated in all diabetics whereas VLDL-Apo B was increased only in diabetics with HbA1c > 7%. Apo CII and Apo CIII levels and also apo CII/apo CIII ratio were also reduced with HbA1c levels of more than 7%. Increases in the apo E and apo E/apo C ratio were also seen in the more hyperglycemic diabetics with HbA1c levels of > 7%. In contrast apo CII and apo CIII levels and also apo CII/apo CIII ratio remained unaltered in diabetic patients with less than 7% HbA1c levels. In these patients increases in the apo E levels were found while the apo E/apo C ratio remained unaltered.

Lipoprotein abnormalities may predispose to an increased risk of coronary heart disease in type II (non-insulin-dependent) diabetes mellitus. To investigate the effects of different treatment modalities, the composition and concentrations of fasting plasma lipoproteins were determined in a cross-sectional study of patients with type II diabetes at diagnosis, treated by diet alone, treated by diet + glibenclamide (2.5 to 15 mg/d for 6 to 48 months), and treated by diet + insulin (25 to 65 U/d for 8 to 144 months). Compared with normal subjects matched for sex, age, body mass index, exercise, alcohol consumption and smoking, type II patients at diagnosis showed increased concentrations of nonesterified and esterified cholesterol, triglyceride, phospholipid, and protein in the very low density lipoprotein (VLDL) fraction. However, the only alteration in VLDL composition was a small decrease in the relative proportion of phospholipid. Apolipoprotein-B and low density lipoprotein (LDL) cholesterol concentrations were also raised in type II patients at diagnosis. Plasma concentrations of high density lipoprotein (HDL) nonesterified and esterified cholesterol, phospholipid, and apo-AI were lower in type II patients at diagnosis. This was largely accounted for by reduced concentrations of these components in the HDL2 subfraction, which retained a normal composition. Type II patients treated by diet alone and diet + glibenclamide exhibited similar abnormalities of plasma lipoprotein concentrations, which are associated with premature coronary disease, to the type II patients at diagnosis. However, in type II patients treated with insulin, plasma lipoprotein concentrations and composition were normal, except LDL cholesterol, which was lower than normal in insulin-treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The composition and concentrations of fasting plasma lipoproteins were determined in a prospective study of 11 +/- 2 (mean +/- 1 SD) months in 16 non-obese (body mass index less than or equal to 30) patients with Type 2 (non-insulin dependent) diabetes mellitus at diagnosis, treated by diet alone or diet plus glibenclamide (2.5-7.5 mg/day). Compared with normal subjects matched for sex, age, body mass index, exercise, alcohol consumption and smoking, Type 2 patients at diagnosis showed increased concentrations of non-esterified and esterified cholesterol, triglyceride, phospholipid and protein in the very low density lipoprotein (VLDL) fraction. The apolipoprotein (apo) B concentrations was also raised, but low density lipoprotein (LDL) cholesterol concentrations were not significantly altered in Type 2 patients at diagnosis. Plasma concentrations of high density lipoprotein (HDL) non-esterified and esterified cholesterol, HDL phospholipid and apo AI were lower in Type 2 patients at diagnosis. This was largely accounted for by a reduced number of HDL2 molecules of normal composition. After treatment of Type 2 patients with diet alone, there was a marginal increase in plasma HDL cholesterol and phospholipid, and in plasma HDL2 cholesterol, phospholipid, protein and apo AI concentrations, in association with reductions of VLDL component concentrations, body mass index and glycaemia. Type 2 patients treated with diet plus glibenclamide exhibited similar abnormalities of plasma lipoprotein concentrations before and after treatment, except for a small reduction in VLDL component concentrations and a slight increase in the apo AI:B ratio. Institution of diet alone and diet plus glibenclamide generally failed to restore VLDL, HDL and HDL2 component concentrations and the apo AI:B ratio to normal.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of sample pre-treatment as a source of variability of apolipoprotein (apo) AI, AII and B assays was demonstrated with lipid dissociating agents. The average mean percentage change ranged from -58 to +133% compared with untreated samples. The apolipoprotein method selected was validated by comparing their concentrations with their corresponding lipoprotein lipid or protein in normal controls and Type 2 (non-insulin-dependent) diabetic patients. The coefficient of variation was maintained below 3.5% for apo AI, AII, B and HDL2-apo AI. The apolipoprotein concentrations of fasting plasma lipoproteins were determined in a cross-sectional study of non-obese (body-mass index less than or equal to 30) patients with Type 2 diabetes mellitus. Compared with normal subjects matched for sex, age, body-mass index, exercise, alcohol consumption and smoking. Type 2 patients at diagnosis showed reduced apo AI and HDL2-apo AI concentrations, lowered apo AI:B ratio and increased concentrations of apo B. Type 2 patients treated by diet alone (for 6-72 months) and diet plus glibenclamide (2.5-15 mg/day for 6-48 months) exhibited similar abnormalities of plasma apolipoprotein concentration to Type 2 patients at diagnosis. However, in Type 2 patients treated with insulin (25-65 U/day for 8-144 months) concentrations of apo AI and HDL2-apo AI, and the apo AI:B ratio were normal. Apo B concentrations were generally lower compared with all groups of non-insulin treated patients. These abnormalities of apolipoprotein metabolism, which are associated with premature coronary disease, are still evident in patients treated by diet and diet plus glibenclamide, but are not seen in Type 2 patients treated with insulin.