KR-31543 reduces the production of proinflammatory molecules in human endothelial cells and monocytes and attenuates atherosclerosis in mouse model

KR-31543, (2S, 3R, 4S)-6-amino-4-[N-(4-chlorophenyl)-N-(2-methyl-2H-tetrazol-5-ylmethyl) amino]-3,4-dihydro-2-dimethyoxymethyl-3-hydroxy-2-methyl-2H-1-benz opyran is a new neuroprotective agent for ischemia-reperfusion damage. It has also been reported that KR-31543 has protective effects on lipid peroxidation and H2O2-induced reactive oxygen species production. In this study, we investigated the anti-inflammatory and anti-atherogenic properties of KR-31543. We observed that KR-31543 treatment reduced the production of MCP-1, IL-8, and VCAM-1 in HUVECs, and of MCP-1 and IL-6 in THP-1 human monocytes. We also examined the effect of KR-31543 on monocytes migration in vitro. KR-31543 treatment effectively reduced the migration of THP-1 human monocytes to the HUVEC monolayer in a dose-dependent manner. We next examined the effects of this compound on atherogenesis in LDL receptor deficient (Ldlr-/-) mice. After 10 weeks of western diet, the formation of atherosclerotic lesion in aorta was reduced in the KR-31543-treated group compared to the control group. The accumulation of macrophages in lesion was also reduced in KR-31543 treated group. However, the plasma levels of total cholesterol, HDL, LDL, and triglyceride were not affected by KR-31543 treatment. Taken together, these results show that KR-31543 has anti-inflammatory properties on human monocytes and endothelial cells, and inhibits fatty streak lesion formation in mouse model of atherosclerosis, suggesting the potential of KR-31543 for the treatment for atherosclerosis.

Reversal of Multidrug Resistance with KR - 30035 ; Evaluated with Biodistribution of Tc - 99m MIBI in Nude Mice Bearing Human Tumor Xenografts / 대한핵의학회잡지

No abstract available.

KR 31378, a potent antioxidant, inhibits apoptotic death of A7r5 cells

This work describes the pharmacological inhibition by KR 31378 and its acetyl metabolite, KR 31612, of the apoptotic cell death induced by H2O2 in the A7r5 cells. Exposure of A7r5 cells to H2O2 (0.5 mM) induced a concentration-dependent cytotoxicity in association with oligonucleosomal DNA fragmentation. H2O2-induced cell death was potently suppressed by KR 31378, KR 31612, alpha-tocopherol or trolox. Additionally, the apoptotic death of A7r5 cells (DNA ladders on electrophoresis) was also strongly suppressed by KR 31378 and KR 31612, but to a less degree by alpha-tocopherol and trolox. As a mechanistic study, incubation with H2O2 markedly showed a decreased Bcl-2 level and, in contrast, increased Bax protein and cytochrome C release, which were significantly and concentration-dependently reversed by KR 31378 and KR 31612 as well as by alpha-tocopherol and trolox. KR 31378 and alpha-tocopherol significantly reduced lipid peroxidation in accordance with reduced intracellular ROS and peroxyl radical. These results suggest that KR 31378 has a therapeutic potential against the apoptotic injury via mediation of antioxidative stress.

Effects of New Nultidrug - Resistance Reversing Agent, KR-30035, on Tumoral Uptake of Tc-99m MIBI In-vitro and In-vivo / 대한암학회지

PURPOSE: Verapamil is one of the most extensively characterized modulators of P-glyco- protein (P-gp) mediated multi-drug resistance (MDR), but its plasma concentration required to reverse MDR can cause cardiovascular toxicity. KR-30035 is a newly synthesized verapamil analogue with more potent cytostatic effects, but has lower cardiovascular effects than verapamil. We have assessed the MDR reversing effects of KR-30035 by measuring Tc-99m MIBI uptake in cultured tumor cells and in nude mice bearing human tumor xenografts. MATERIALS AND METHODS: In-vitro uptake of Tc-99m MIBI was measured in murine leukemia cells (L-1210) and those MDR-positive variants after incubation with different concentrations of KR-30035. Results were compared to those with verapamil. Organ and tumoral uptake of Tc-99m MIBI was compared between P-gp (+) human colon cancer (HCT15 cells) and P-gp (-) lung cancer (A549 cells) in nude mice, treated with either KR-30035 or verapamil. RESULTS: There was no significant difference in in-vitro uptake of Tc-99m MIBI between verapamil and KR-30035 group at any concentrations. MIBI uptake in P-gp (+) cells continuously increased either with verapamil or KR-30035 in a dose-dependent manner. Tc-99m MIBI uptake ratios of the tumor [P-gp (+' tumor uptake divided by P-gp (-) uptake] were significantly higher with KR-30035 than with verapamil in tumor bearing nude mice. Washout rate of Tc-99m MIBI from P-gp (+) HCT15 cells was lower in verapamil or KR-30035 groups than in the control group, which was 0.19, 0.19 and 0.27 respectively. CONCLUSION: These studies revealed that KR-30035 can potentially be used as an active modulator of MDR, with its significantly lesser cardiovascular toxicity than verapamil. Our results warrants further evaluation of this novel agent.

Mechanisms underlying relaxations caused by angiotensin II and its analogs in isolated rabbit mesenteric artery

In the present study, we characterized the angiotensin II (AII)-induced relaxations in the phenylephrineprecontracted rabbit mesenteric arteries with endothelium. 1) AII-induced relaxation was consistently observed in the rabbit mesenteric arteries with and without endothelium, but not in the aortic segment with endothelium. 2) AII-induced endothelium-dependent relaxation was markedly inhibited by Nw-nitro-L-arginine (L-NNA, 100 micrometer), methylene blue (10 micrometer) and LY83583 (10 micrometer), respectively. 3) Inhibition of cyclooxygenase with indomethacin (10 micrometer) strongly decreased the vasorelaxant response to AII irrespective of the presence of endothelium. 4) 7-Ethoxyresorufin (1 micrometer) and clotrimazole (1 micrometer), inhibitors of cytochrome P-450-dependent arachidonic acid metabolism, greatly attenuated the vasodilator response to All. 5) Carbacyclin, arachidonic acid and prostaglandin F2alpha, (PGF2alpha) caused concentration-dependent relaxations in the mesenteric artery with endothelium, which were inhibited by L-NNA and methylene blue. 6) AII and PGF2alpha, significantly stimulated cyclic GMP formation in the mesenteric arteries with endothelium, which was inhibited by L-NNA and methylene blue, respectively. 7) AII enhanced synthesis of PGF2a and 6-keto PGF1a from the arterial segments with endothelium, which was inhibitable by indomethacin, but not by L-NNA. In conclusion, the vasorelaxant responses to AII of the rabbit mesenteric artery with endothelium are subserved by arachidonic acid and its metabolites produced via activation of cyclooxygenase and cytochrome P-450 enzyme as well as by nitric oxide.

In vitro pharmacological characteristics of SKP-450, a novel K+ channel opener, in non-vascular smooth muscles in comparison with levcromakalim

In the present study, we characterized the non-vascular smooth muscle relaxant effects of a novel benzoyran derivative, SKP-450 (2-(2"(1",3"-dioxolone)-2-methyl-4-(2'-oxo-1'-pyrrolidinyl)-6-nitro- 2H-1-benzopyran) and its metabolite, SKP-310, in comparison with levcromakalim (LCRK). In the rat stomach fundus, the spontaneous motility stimulated by 10-6.5 M bethanechol was completely eliminated not only by 10(-7) M SKP-450 but also by 10(-6) M LCRK, which were blocked by 10(-6) M glibenclamide. The inhibitory effect of SKP-450 (pD2, 3.94 +/- 0.66) was much less than LCRK (pD2, 5.73 +/- 0.38, P < 0.05). In the bethanechol (10(-6.5) M)-stimulated urinary bladder, the tonus was decreased in association with elimination of spontaneous motility by 10(-7) M SKP-450 and 10-6 M LCRK (pD2, 6.77 +/- 0.06) (P < 0.05), which were inhibitable by 10-6 M glibenclamide. The inhibitory effect of SKP-450 (pD2, 7.66 +/- 0.05) was significantly more potent than that of LCRK (pD2, 6.77 +/- 0.06, P < 0.05). In the rat uterus stimulated by PGF2alpha (10(-7) M), both increased tonus and spontaneous motility were eliminated by 10(-6) M LCRK with slight depression of the tonus, but not by SKP-450 (10(-5) M). The stimulated trachea of guinea-pig by 10-6.5 M bethanechol was moderately suppressed by SKP-450 (10(-6)~10(-5) M) but little by SKP-310. In association with the relaxant effects, SKP-450 (10(-6) M) and LCRK (10(-5) M) caused a significant stimulation of the 86Rb efflux from rat urinary bladder and stomach fundus, which were antagonized by 10(-5) M glibenclamide, whereas the K+ channel openers could not exert a stimulation of the 86Rb efflux from rat uterus. In conclusion, it is suggested that SKP-450 exerts potent relaxant effects on the urinary bladder detrusor muscle and duodenum, whereas it shows much less effect on stomach fundus and uterus as contrasted to LCRK.