Inhibition of angiogenesis and tumor growth by a novel 1,4-naphthoquinone derivative.

Hit, Lead & Candidate Discovery Antiangiogenesis therapy is a promising way for treatment of solid cancers, and many angiogenesis inhibitors that target vascular endothelial growth factor (VEGF) or its receptors have been developed. We explored novel antiangiogenic compounds other than anti-VEGF drugs by screening our synthetic compound library and found that 6-thiophen-3-yl-2-methoxy-1,4-naphthoquinone (6-TMNQ) had potential as a novel angiogenesis inhibitor. This paper describes the effects of 6-TMNQ on angiogenesis and tumor growth in vitro and in vivo. 6-TMNQ inhibited serum-, VEGF-, and basic fibroblast growth factor (bFGF)-stimulated proliferation of endothelial cells in a concentration-dependent manner, but had no effect on the proliferation of fibroblasts. VEGF-induced activation of VEGF receptor-2 in endothelial cells was not affected by the compound. 6-TMNQ markedly abrogated both migration and tube formation of endothelial cells. Orally administered 6-TMNQ inhibited angiogenesis in response to VEGF or bFGF in mice in a dose-dependent manner. Furthermore, when tumor-bearing mice were treated with 6-TMNQ, increase in tumor size was significantly prevented due to inhibition of angiogenesis in the tumor tissues. These results demonstrate that 6-TMNQ is an orally available compound that selectively inhibits endothelial cell proliferation and migration, and abrogates angiogenesis, resulting in the prevention of tumor growth. The mechanism of 6-TMNQ action is different from that of conventional anti-VEGF drugs.

Inhibition of the proliferation and acceleration of migration of vascular endothelial cells by increased cysteine-rich motor neuron 1.

Cysteine-rich motor neuron 1 (CRIM1) is upregulated only in extracellular matrix gels by angiogenic factors such as vascular endothelial growth factor (VEGF). It then plays a critical role in the tube formation of endothelial cells. In the present study, we investigated the effects of increased CRIM1 on other endothelial functions such as proliferation and migration. Knock down of CRIM1 had no effect on VEGF-induced proliferation or migration of human umbilical vein endothelial cells (HUVECs), indicating that basal CRIM1 is not involved in the proliferation or migration of endothelial cells. Stable CRIM1-overexpressing endothelial F-2 cells, termed CR1 and CR2, were constructed, because it was difficult to prepare monolayer HUVECs that expressed high levels of CRIM1. Proliferation was reduced and migration was accelerated in both CR1 and CR2 cells, compared with normal F-2 cells. Furthermore, the transient overexpression of CRIM1 resulted in decreased proliferation and increased migration of bovine aortic endothelial cells. In contrast, neither proliferation nor migration of COS-7 cells were changed by the overexpression of CRIM1. These results demonstrate that increased CRIM1 reduces the proliferation and accelerates the migration of endothelial cells. These CRIM1 effects might contribute to tube formation of endothelial cells. CRIM1 induced by angiogenic factors may serve as a regulator in endothelial cells to switch from proliferating cells to morphological differentiation.

Resveratrol inhibits angiogenic response of cultured endothelial F-2 cells to vascular endothelial growth factor, but not to basic fibroblast growth factor.

Resveratrol, a natural polyphenol in grapes, is known to prevent the cardiovascular diseases and to exert the antiangiogenic effect in in vivo models with vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF). We examined the effect of resveratrol on tubule formation of cultured endothelial F-2 cells. In collagen gel matrix, F-2 cells formed an extended network of tubular structures in response to VEGF or bFGF. Resveratrol dose-dependently prevented the VEGF-induced tubule formation, but failed to inhibit the angiogenic response to bFGF. We next examined whether the inhibition of nitric oxide (NO) production is linked to the antiangiogenic effect of resveratrol on VEGF-stimulated F-2 cells, because NO plays a crucial role in VEGF-induced tubular network formation. NO production was increased by VEGF, but not by bFGF, and resveratrol inhibited VEGF-stimulated NO production. N(G)-nitro-L-arginine methyl ester (L-NAME) potently inhibited NO production under all conditions, including VEGF stimulation, and abrogated VEGF-induced tubule formation. However, L-NAME did not inhibit bFGF-induced tubule formation. To investigate the bFGF-induced in vivo antiangiogenic effect of resveratrol, we examined the effect of resveratrol on prostaglandin E(2) (PGE(2)) production and cyclooxygenase (COX) expression in NRK-F fibroblasts. COX-2 and its derived PGE(2) are important factors for bFGF-induced in vivo angiogenesis. Resveratrol dose-dependently prevented both COX-2 induction and PGE(2) production in bFGF-stimulated fibroblasts. These results suggest that resveratrol exerts the inhibitory effects on VEGF- and bFGF-induced angiogenesis through different mechanisms including inhibition of NO production in VEGF-stimulated endothelial cells and inhibition of COX-2 induction in bFGF-stimulated fibroblasts.

Carnosine facilitates nitric oxide production in endothelial f-2 cells.

We examined the effect of carnosine (beta-alanyl-histidine) on nitric oxide (NO) production and endothelial NO synthase (eNOS) activation in endothelial F-2 cells. Carnosine enhanced NO production in a dose-dependent manner, and the stimulatory effect of carnosine was observed at concentrations exceeding 5 mM. The carnosine-stimulated NO production was inhibited by N(G)-nitro-L-arginine methyl ester, but not by N(G)-nitro-D-arginine methyl ester. In contrast, beta-alanine, histidine (carnosine components) and anserine (N-methyl carnosine) failed to increase NO production. Carnosine had no effect on NO production for the initial 5 min, but thereafter resulted in a gradual increase in NO production up to 15 min. Carnosine did not induce phosphorylation of eNOS at Ser1177. The carnosine-induced increase in NO production was observed even when extracellular Ca2+ was depleted by ethylene glycol bis(2-aminoethyl ether)-N,N,N'-N'-tetraacetic acid however, the effect was abolished upon depletion of intracellular Ca2+ by BAPTA. After F-2 cells were incubated with carnosine for 4 min, intracellular Ca2+ concentration gradually increased. The carnosine-induced increase in intracellular Ca2+ concentration occurred even in the absence of extracellular Ca2+. These results indicate that carnosine facilitates NO production in endothelial F-2 cells. It is also suggested that eNOS is activated by Ca2+, which might be released from intracellular Ca2+ stores in response to carnosine.

Differential effect of resveratrol on nitric oxide production in endothelial f-2 cells.

We examined the rapid effect of resveratrol on nitric oxide (NO) production in endothelial F-2 cells. During an incubation period of 10 min, resveratrol at low concentrations (<20 microM) had no effect on NO production, whereas it significantly increased NO production at high concentrations (>50 microM). In contrast, pretreatment with resveratrol at low concentrations caused a significant decrease in vascular endothelial growth factor (VEGF)-stimulated NO production. Resveratrol failed to induce phosphorylation of endothelial NO synthase (eNOS) and VEGF receptor and did not affect autophosphorylation of the VEGF receptor. However, resveratrol markedly suppressed VEGF-induced eNOS phosphorylation. Resveratrol at high concentrations reduced the viability of F-2 cells as determined by 3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and dye exclusion methods. Resveratrol-stimulated NO production was completely abolished by the depletion of extracellular Ca2+. These results indicate that resveratrol stimulates NO production by a Ca(2+)-dependent mechanism and reduces VEGF-stimulated NO production by impairing a Ca(2+)-independent mechanism in endothelial F-2 cells. However, the stimulatory effect of resveratrol may be partly attributed to its cytotoxicity.

Cyclophosphamide enhances TNF-alpha-induced apoptotic cell death in murine vascular endothelial cell.

Cyclophosphamide (CPA) is one of the therapeutic agents for systemic inflammatory disorders. In murine dermal endothelial cells (F-2), 4-hydroxycyclophosphamide (4-HC), which is active metabolite of CPA, enhanced TNF-alpha-induced DNA fragmentation. In addition, 4-HC was shown to elevate TNF-alpha-induced caspase-3 activation. Caspase-8 activation was identified by the treatment of TNF-alpha, whereas 4-HC was no effect. In contrast, only when treated with 4-HC, caspase-9 activation and the increase in the intracellular expression of Bax were detected. These results suggest that CPA may sensitize endothelial cells to TNF-alpha-induced apoptosis through a mitochondria-dependent pathway and clinically may contribute to the limitation of inflammatory process.

[Bacteriological features of Mycobacterium haemophilum isolated from skin lesions in an immunodeficient patient].

A 53-year-old, male patient presented with pain in the middle area of the back of his left foot. The painful area was associated with a reddish dome-shaped swelling of 24 by 18 mm which had ulcerated in the center part. Histopathologically, the cutaneous lesion consisted of an ulcer surrounded by abscess and granuloma and numerous acid-fast organisms were observed. Subsequently, the area just below the left inguinal area developed redness and swelling approaching the size of a quail egg. The patient responded favorably with rifampicin, levofloxacin, and minocycline therapy. The patient was immunodeficient, but negative for HIV-1 and HIV-2 antibodies and the etiology of his immunodeficient state is unclear. Skin tissues or pus were cultured at 37 degrees C on 2% Ogawa and BBL MGIT. Acid-fast organisms were recovered on MGIT within 4 to 12 days, while 2% Ogawa medium failed to recover acid-fast bacteria. Using growth from the positive MGIT tube as inoculum, MycoBroth, 7H9 broth, 7H11.2% Ogawa supplemented with or without iron complexes, and blood agar were inoculated and cultured at 30 and 37 degrees C. Growth at 30 and 37 degrees C was seen with MycoBroth, 7H9, hemin (60 microM) or ferric ammonium citrate (15 mg/ml) supplemented 7H11 and blood agar as well as 7H11 supplemented with factor X. Growth at 30 degrees C only was observed for ferric ammonium citrate supplemented 7H9 and 2% Ogawa. Generally, growth at 30 degrees C was better than that at 37 degrees C in all media. No growth at either temperature was observed with hemin or factor X supplemented 2% Ogawa. With respect to the biochemical characterization, the isolate was negative for niacin, nitrate reduction, urease, arylsulfatase, Tween 80 hydrolysis, catalase, 68 degrees C catalase, acid phosphatase, and tellurite reduction, while strongly positive for neutral red test. Sequencing of the 16S rRNA gene showed the isolate to be consistent with Mycobacterium haemophilum. Based on the composite characterization, the isolate was identified as M. haemophilum. This is the second case report of M. haemophilum infection in Japan in the literature.

Roles of cell adhesion molecules in tumor angiogenesis induced by cotransplantation of cancer and endothelial cells to nude rats.

Roles of cell adhesion molecules mediating the interaction of cancer and endothelial cells in tumor angiogenesis were investigated using new in vitro and in vivo model systems with a cultured murine endothelial cell line (F-2) and human cultured epidermoid cancer cells (A431). The A431 cells exhibited typical in vitro cell adhesion to the endothelial F-2 cells. The initial step of adhesion was mediated by sialyl Lewis(x) (Le(x)) and sialyl Le(a), the carbohydrate determinants expressed on the cancer cells, and E-selectin expressed constitutively on F-2 cells. Prolonged culture led to the implantation of cancer cells into the monolayer of the F-2 cells, which was mediated mainly by alpha(3)beta(1)-integrin. F-2 cells cultured on Matrigel showed evident tube formation, and coculture of F-2 cells with A431 cells led to the formation of A431 cell nests constantly surrounded by tube-like networks consisting of F-2 cells. This in vitro morphogenesis was inhibited by the addition of anti-sialyl Le(x)/Le(a) or anti-beta(1)-integrin antibodies, which led to the formation of cancer cell aggregates that were independent from the F-2 cell networks. This in vitro morphological appearance was exactly reproduced in the in vivo tumors, which were formed when the mixture of A431 and F-2 cells at the ratio of 10:1 were cotransplanted s.c. into the back of nude rats. The tumors of A431 supplemented with F-2 cells were profoundly vascularized throughout by the tubular structures formed by F-2 cells, the lumen of which contained the host rat blood cells. The tumor mass thus formed was an average 5.8-fold as large as control A431 tumors that were grown without F-2 cells. The co-injection of anti-Le(x)/Le(a) or anti-beta(1)-integrin antibodies produced a marked reduction in the size of A431 tumors, which were not vascularized and accompanied an independent tiny remnant clump of F-2 cells. The size of these A431 tumors did not differ significantly from those of control A431 tumors raised without F-2 cells. These results indicate that the interaction of tumor cells and endothelial cells in orderly tumor angiomorphogenesis is highly dependent on the action of cell adhesion molecules mediating the adhesion of cancer cells to endothelial cells, inhibition of which remarkably retards tumor growth and angiogenesis.

Cytotoxicity of IFN-gamma and TNF-alpha for vascular endothelial cell is mediated by nitric oxide.

Endothelial cell injury is a critical event in tissue damage accompanying inflammation, in which both inflammatory cytokines and reactive oxygen species may play pivotal roles, although the exact mechanism has not yet been clarified. We found that combined stimulation with interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) induced both cytotoxicity to murine vascular endothelial cell line F-2 and an increase in nitric oxide (NO). Therefore, in the present study, the implication of NO in cytotoxicity was examined. A potent iNOS-specific inhibitor ONO-1714 completely blocked both cytokine-induced cytotoxicity and NO production. NO scavengers such as carboxy-PTIO and hemoglobin blocked cytotoxicity. Moreover, exogenous NO from NOC 18 also caused cytotoxicity. These results together demonstrated that cytotoxicity of IFN-gamma and TNF-alpha for endothelial cell F-2 was mediated by NO, suggesting a pathogenic role of cytokine-induced NO production in endothelial damage under inflammatory conditions.

[Antimicrobial susceptibility and beta-lactamase productivity of recent clinical isolates during the period between December 1999 and February 2000].

Antimicrobial susceptibility testings of 24 antimicrobial agents against 605 clinical strains belonging to 10 species were carried out according to the micro-broth dilution method of NCCLS M7-A4. The productivity of beta-lactamase was also determined against them isolated at 8 medical facilities in Nagano prefecture, Japan during the period between December 1999 and February 2000. When applied the nitrocefin method, beta-lactamase productivity was demonstrated to be positive for 89.2% of 74 S. aureus, 4.3% of 94 H. influenzae, and 100% of 69 M. (B.) catarrhalis isolates. On the other hand, when used the acidometry method, penicillinase/cephalosporinase were found to be positive for 21.2%/9.6% of 52 E. coli, 29.0%/3.2% of 31 K. pneumoniae, 53.2%/100% of 47 E. cloacae, 0%/11.1% of 99 S. marcescens, and 25.9%/55.6% of 54 P. aeruginosa isolates, respectively. Among the beta-lactamase-producers including P. aeruginosa isolates, only 2 E. coli isolates were found to be ESBL-producers. Besides, 9.6% (9/94) of H. influenzae isolates were proved to be BLNAR strains.