New antimalarial fusarochromanone analogs produced by the fungal strain Fusarium sp. FKI-9521.

Two new antimalarial compounds, named deacetyl fusarochromene (1) and 4'-O-acetyl fusarochromanone (2), were discovered from the static fungal cultured material of Fusarium sp. FKI-9521 isolated from feces of a stick insect (Ramulus mikado) together with three known compounds fusarochromanone (3), 3'-N-acetyl fusarochromanone (4), and 5 (fusarochromene or banchromene). The structures of 1 and 2 were elucidated as new analogs of 3 by MS and NMR analyses. The absolute configurations of 1, 2, and 4 were determined by chemical derivatization. All five compounds showed moderate in vitro antimalarial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with IC50 values ranging from 0.08 to 6.35 µM.

Development and evaluation of a novel antibody-photon absorber conjugate reveals the possibility of photoimmunotherapy-induced vascular occlusion during treatment in vivo.

Photodynamic therapy (PDT) utilize a photosensitizing agent and light for cancer therapy. It exerts anti-cancer effect mainly by inducing vascular occlusion at the irradiated site. By controlling the irradiation area, PDT can be used in a tumor-specific manner. However, the non-specific cellular damage in the surrounding normal tissue is still a serious concern. Photoimmunotherapy (PIT) is a new type of targeted cancer therapy that uses an antibody-photon absorber conjugate (APC). The superiority of PIT to PDT is the improved target specificity, thereby reducing the damage to normal tissues. Here, we developed a novel APC targeting epithelial cell adhesion molecule (EpCAM) as well as a negative control APC that does not bind to the EpCAM antigen. Our in vitro analysis of APC cytotoxicity demonstrated that the EpCAM APC, but not the negative control, was cytotoxic to EpCAM expressing COLO 205 cells after photoirradiation, suggesting that the cytotoxicity is antigen-dependent. However, in our in vivo analysis using a mouse xenograft tumor model, decreased volume of the tumors was observed in all the mice treated with irradiation, regardless of whether they were treated with the EpCAM APC or the negative control. Detailed investigation of the mechanism of these in vivo reveal that both APCs induce vascular occlusion at the irradiation site. Furthermore, the level of vascular occlusion was correlated with the blood concentration of APC, not the tumor concentration. These results imply that, similar to PDT, PIT can also induce non-targeted vascular occlusion and further optimization is required before widespread clinical use.

Comparison of the antiatherosclerotic effects of dihydropyridine calcium channel blocker and HMG-CoA reductase inhibitor on hypercholesterolemic rabbits.

The antiatherosclerotic effects of the dihydropyridine-type calcium channel blocker, benidipine hydrochloride (benidipine), and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, pravastatin sodium (pravastatin), were compared in hypercholesterolemic rabbits. Male, New Zealand white rabbits were fed a 0.5% cholesterol diet. Pravastatin (10 mg/kg) or benidipine (10 mg/kg) was orally administered once daily after start of feeding. After 8 weeks of cholesterol feeding, serum cholesterol was increased and endothelial function of thoracic aorta was impaired. Pravastatin prevented elevation of serum cholesterol and aortic tunica intima hyperplasia. Although benidipine had little effect on serum cholesterol, it significantly inhibited aortic tunica intima hyperplasia and impairment of endothelial function. Expression levels of the vascular cell adhesion molecule-1 (VCAM-1) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) mRNA in aorta of hypercholesterolemic rabbit were higher than those of normal rabbit. Benidipine significantly prevented upregulation of VCAM-1 mRNA expression and showed a tendency to inhibit elevation of LOX-1 mRNA expression. Pravastatin significantly prevented upregulation of both VCAM-1 and LOX-1 mRNA expression. The results demonstrate that pravastatin inhibits increase of serum cholesterol and vascular dysfunction in hypercholesterolemic rabbit. Benidipine is effective in preventing vascular hyperplasia without altering serum cholesterol levels and this may be due to inhibition of expression of VCAM-1.

Novel anticarcinoembryonic antigen antibody-drug conjugate has antitumor activity in the existence of soluble antigen.

Carcinoembryonic antigen (CEA) is a classic tumor-specific antigen that is overexpressed in several cancers, including gastric cancer. Although some anti-CEA antibodies have been tested, to the best of our knowledge, there are currently no clinically approved anti-CEA antibody therapies. Because of this, we have created the novel anti-CEA antibody, 15-1-32, which exhibits stronger binding to membrane-bound CEA on cancer cells than existing anti-CEA antibodies. 15-1-32 also shows poor affinity for soluble CEA; thus, the binding activity of 15-1-32 to membrane-bound CEA is not influenced by soluble CEA. In addition, we constructed a 15-1-32-monomethyl auristatin E conjugate (15-1-32-vcMMAE) to improve the therapeutic efficacy of 15-1-32. 15-1-32-vcMMAE showed enhanced antitumor activity against gastric cancer cell lines. Unlike with existing anti-CEA antibody therapies, antitumor activity of 15-1-32-vcMMAE was retained in the presence of high concentrations of soluble CEA.

Molecular evidence of the existence of two sibling species within the echinothurioid echinoid Asthenosoma ijimai from Japanese waters.

The echinoid, Asthenosoma ijimai belonging to the order Echinothurioida from Japanese waters shows the geographical variation in morphological and ecological characters. The echinothurioid from Ryukyu Islands in southern Japan is cleary different from that of Sagami Bay and Suruga Bay in the middle part of Japan at non-molecular level. Their phylogenetic and taxonomic relationships were studied at the molecular level by allozyme analysis. The results demonstrated that the two echinothurioids from Ryukyu Islands and Sagami Bay do not share gene pools with each other, and they were fixed for different alleles at five genetic loci (Mdh, G6pd, Po, Alk-3 and Est-7) in a total of 23 enzyme genetic loci scored. This indicates no gene flow between the two echinothurioids, and is a molecular evidence for that they are reproductively isolated and genetically distinct species. The Nei's genetic distance (D=0.181) between the two were significantly higher than those between conspecific local populations, and comparable to those between closely related species in many other animals containing echinoderms. The present molecular data are well consistent with the non-molecular evidence from morphology, developmental biology and ecology. Putting these data together, we propose that the two echinothurioids should be classified as two sibling species of the genus Asthenosoma and would like to give the following scientific names: the echinothurioid species from Sagami Bay is Asthenosoma ijimai and that from Ryukyu Islands is A. ijimai R.

Benidipine, a calcium channel blocker, regulates proliferation and phenotype of vascular smooth muscle cells.

Hyperproliferation of phenotypically modified vascular smooth muscle cells (VSMCs) is one of the major factors in the development of atherosclerosis and restenosis. Previously it was demonstrated that benidipine, a dihydropyridine-calcium channel antagonist, reduced neointimal formation in a rat balloon-injury model. In the present study, we examined the effect of benidipine on the phenotypic modulation and proliferation of VSMCs, using primary cultures of rat VSMCs. In the absence of drug treatment, protein levels of the smooth muscle specific markers, such as smooth muscle myosin heavy chain-1 (SM1), calponin 1, and alpha-actin, decreased during culture. However, treatment of VSMCs with benidipine (3 - 10 micromol/L) for 1 week reversed the effect in a concentration-related manner so that high levels of marker proteins were maintained. The expression of calponin mRNAs was reduced markedly during 1-week culture, and treatment with benidipine (3 micromol/L) significantly inhibited the reduction. Treatment with benidipine for 2 days increased the level of p21 protein and partially reduced p70 S6 kinase 1 (p70S6K1) activity. These data suggest that benidipine may arrest the growth of VSMCs, thereby preventing cell dedifferentiation. These additional properties of benidipine suggest that the drug should provide useful therapy for atherosclerosis and restenosis.

Effects of combination of angiotensin receptor blocker and calcium channel blocker on ox-LDL levels and cardiovascular dysfunction in Dahl rats.

In an effort to assess the cardiovascular benefits of combined angiotensin receptor blockage and calcium channel antagonism, we assessed the chronic effects of the angiotensin type 1 receptor blocker candesartan, the calcium channel blocker benidipine, and the use of a combination therapy in Dahl salt-sensitive (DS) rats. DS rats receiving a high salt diet were treated with either benidipine (4 mg/kg), candesartan (1 mg/kg) or both. Rat blood pressure was measured using a tail-cuff method. Following 12 weeks, the effect on heart weight, plasma-oxidized low-density lipoprotein (ox-LDL) level, endothelium-dependent vasorelaxation, and histology of the heart and aorta was assessed. Blood pressure, heart weight and plasma ox-LDL levels increased, while endothelium-dependent vasorelaxation decreased in the DS rats. Candesartan and benidipine inhibited the increase in blood pressure and heart weight, and the decrease in endothelium-dependent vasorelaxation. The use of benidipine alone or a combination significantly inhibited the increase in ox-LDL levels, whereas candesartan alone had no significant effect on ox-LDL levels. The present findings indicate that, if the monotherapy using ARB could not achieve adequate control of blood pressure, the combination therapy with ARB and benidipine provides the additional reductions in hypertension and cardiac hypertrophy. Moreover, the combination therapy inhibits cardiovascular dysfunction and ox-LDL levels more effectively than use of ARB alone. These results contribute to the possibility of lowering ox-LDL levels as a means of enhancing cardiovascular protection.

L-ascorbic acid stimulates expression of smooth muscle-specific markers in smooth muscle cells both in vitro and in vivo.

The dedifferentiation of vascular smooth muscle cells (VSMCs) plays a critical role in the progression of atherosclerosis and restenosis after angioplasty. Thus, factors that stimulate smooth muscle cell differentiation should be useful for therapy for these diseases. Previously, we found that l-ascorbic acid (L-Asc) induces the expression of smooth muscle-specific genes in a pluripotent bone marrow stromal cell line, TBR-B. This finding suggests that l-Asc stimulates the differentiation of smooth muscle cells. In the present study, we investigated the effects of l-Asc and its derivatives on the differentiation state of VSMCs in vitro and in vivo. l-Asc and its long-lasting derivatives stimulated the production of smooth muscle-specific myosin heavy chain-1 (SM1) and calponin 1 in a dose-dependent manner in rat cultured VSMCs, and the elevated production of SM1 and calponin 1 was maintained for at least 2 weeks. Moreover, oral administration of 3 g/kg of l-Asc to the balloon-injured rats induced a higher expression of SM1 and calponin 1 in the injured arteries compared with that from administration of the delivery vehicle alone. These data demonstrated new biologic activity, such as the stimulation of VSMC differentiation, of l-Asc and its long-lasting derivatives. In addition, these compounds may serve as useful tools for analysis of the differentiation of VSMCs and for therapy for vascular diseases.