The results suggest that Wf-536 is a potentially valuable drug for preventing tumor metastasis both in monotherapy and in combination with an antineoplastic drug.

No abstract

-Monkey cerebral artery strips partially contracted with prostaglandin F2a responded to histamine with biphasic patterns of relaxation. The delayed and sustained relaxation was suppressed by cimetidine, whereas the phasic response was abolished by treatment with chlorpheniramine and NG nitro-L-arginine (L-NA), a nitric oxide (NO) synthase inhibitor. The inhibition by L-NA was reversed by L-arginine. D-NA was without effect. Endothelium denudation abolished the phasic relaxation. We hypothesized that endothelium-dependent, phasic relaxations caused by histamine are mediated by NO that is released by Hi-receptor stimulation, whereas the sustained relaxation is associated with the activation of H2-receptors in the smooth muscle of monkey cerebral arteries.Keywords: Histamine, Nitric oxide, Endothelium, Hi-receptor subtype, Cerebral artery (monkey)The complexity of vascular responses to histamine is based on its actions on histaminergic receptor subtypes, H1 and H2, in the endothelium and smooth muscle and on the release of chemical mediators, such as endothelium-derived relaxing factor (EDRF) and pros taglandins (PGs), from endothelial and subendothelial tissues (1 6). Histamine-induced relaxations mediated by EDRF have been reported in human, monkey and rabbit cerebral arteries (7, 8); human and monkey coronary arteries (9, 10); guinea pig pulmonary arteries (11); human umbilical vessels (12); monkey pulmonary veins (13); and rat aortas (14). The participation of EDRF is postulated from evidence that the relaxation is dependent on the endothelium and is suppressed by treatment with oxyhemoglobin, methylene blue or anti oxidants. EDRF has been proposed to be nitric oxide (NO) or an unstable S-nitroso compound that releases the NO radical (15, 16). However, endothelium-depend ent relaxations are not always associated with NO or its analog (17, 18).We have reported that endothelium-dependent re laxations caused by histamine in monkey cerebral arter ies are significantly inhibited by methylene blue and chlorpheniramine, suggesting the involvement of the endothelial H1-receptor subtype in the release of EDRF (7). Despite this conclusion, whether NO was actually involved in the response could not be determined. Methylene blue has many actions other than the inhibi tion of soluble guanylate cyclase (19,20), whereas NO synthase inhibitors, including NG-monomethyl-L-argi nine, NG-nitro-L-arginine (L-NA), L-NA methylester, etc. (21), are selective in depressing the synthesis of NO. Thus, the role of NO can be evaluated more speci fically by the use of these inhibitors. In addition, the effectiveness of NO synthase inhibitors on the endo thelium-dependent relaxation has not been evaluated in cerebral arteries.Therefore, the present study was undertaken to eluci date the involvement of endothelium-derived NO in the histamine-induced relaxation of isolated monkey cere bral arteries, with special reference to the histaminergic receptor subtypes. MATERIALS AND METHODS PreparationJapanese monkeys (Macaca fuscata) of eith...

1. Rho-associated coiled-coil forming protein serine/threonine kinase (ROCK) is involved in the development of tumour metastasis. Wf-536, (+)-(R)-4-(1-Aminoethyl)-N-(4-pyridyl) benzamide monohydrochloride, a novel inhibitor of ROCK, inhibits tumour metastasis in some animal models. To metastasise, tumour cells have to disturb the tight intercellular junctions and the basement membrane matrix of the host tissue, which, respectively, create an intercellular barrier and the extracellular membrane. To clarify the mechanism of Wf-536 in inhibition of tumour metastasis, we analysed the effect of Wf-536 on the transition of tumour cells through the host cell layer and the basement membrane in in vitro systems. 2. In a coculture system of human fibrosarcoma HT1080 cells plated on a monolayer of human ECV304 cells, Wf-536 (0.3-3 micromol/L) inhibited the paracellular infiltration of tumour cells. 3. Wf-536 (3-30 micromol/L) inhibited the invasion of tumour cells through the reconstituted basement membrane (Matrigel) layer. 4. Wf-536 (10-30 micromol/L) inhibited the migration of tumour cells. At 0.3-3 micromol/L, Wf-536 also restrained hepatocyte growth factor/scatter factor (HGF)-induced increases in paracellular permeability of the ECV304 cell layer. 5. These results suggest that Wf-536 suppresses tumour metastasis by both enhancing the barrier function of host cell layers and inhibiting tumour cell motility at the stage of host tissue penetration by metastatic tumour cells.

For NAD-malic enzyme (NAD-ME)-type C4 photosynthesis, two types of aspartate aminotransferase (AAT) are involved. We examined the expression pattern of the Panicum miliaceum mitochondrial Aat gene (PmAat) and P. miliaceum cytosolic Aat gene (PcAat) in transgenic rice plants, which were specifically expressed in bundle sheath cells (BSCs) and mesophyll cells (MCs), respectively. Expression of a beta-glucuronidase (GUS) reporter gene under the control of the PcAat promoter was regulated in an organ-preferential and light-dependent manner in the transgenic rice plants. However, the PmAat promoter drove the GUS expression in all organs we tested without light dependency, and this non-preferential expression pattern was also observed in transgenic rice with introduction of the intact PmAat gene. The expression patterns of the rice counterpart Aat genes to PmAat or PcAat showed that the rice mitochondrial Aat (RmAat1) gene was expressed in all organs tested in a light-independent manner, while expression of the rice cytosolic Aat (RcAat1) gene showed an organ-preferential and light-dependent pattern. Taking these results together, we can generalize that the regulatory system of BSC-specific or light-dependent expression of mitochondrial Aat is not shared between P. miliaceum (C4) and rice (C3) and that the expression of the C4 genes introduced into rice mimics that of their counterpart genes in rice.