KR-31831, a new synthetic anti-ischemic agent, inhibits in vivo and in vitro angiogenesis

KR-31831 improves survival and protects hematopoietic cells and radiosensitive tissues against radiation-induced injuries in mice

This study explored the radioprotective effects and possible underlying mechanisms of KR-31831 against radiation-induced injury in a mouse model. KR-31831 (30 and 50 mg/kg) was administered to mice 24 h and 30 min before exposure to a single lethal or sublethal dose of whole-body irradiation (WBI) (7 or 4 Gy, respectively). These animals were then evaluated for changes in mortality, various hematological and biochemical parameters, and histological features in response to these treatments. In addition, RNA sequencing was used to profile the radiation-induced transcriptomic response in the bone marrow cells. The results showed that KR-31831 dose-dependently prolonged the 30-day survival period and prevented damage to radiation-sensitive organs, such as the intestine and testis, in response to WBI. Damage to the hematopoietic system was also notably improved in the KR-31831-treated mice, as evidenced by an increase in bone marrow and peripheral blood cells, as well as recovery of the histopathological characteristics of the bone marrow. These protective effects were achieved, at least in part, via the suppression of radiation-induced increases in apoptotic cell death and erythropoietin levels in the plasma. Furthermore, the gene expression profiles of the bone marrow cells of the WBI-treated mice suggested that KR-31831 upregulates the expression of the genes involved in regulating apoptosis and modulating the immune response, both of which are required for protecting the bone marrow. These results suggest the potential therapeutic efficacy of KR-31831 for protection against radiation-induced injury.

Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of ortho-Quinone Methides

We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in high yield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed into functionalized chromanes or chromene. For example, BW683C was effectively synthesized from 5-chlorosalicylaldehyde with 4-chlorostyrene in two steps in excellent yield. The present reaction thus provides versatile access to functionalized electron-deficient chromanes and chromenes and therefore constitutes a promising tool for the synthesis of biologically and photochemically active molecules.

Melatonin suppresses tumor progression by reducing angiogenesis stimulated by HIF-1 in a mouse tumor model

The sustained expansion of a tumor mass requires new blood vessel formation to provide rapidly proliferating tumor cells with an adequate supply of oxygen and nutrients. Hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumor angiogenesis and growth by regulating the transcription of genes in response to hypoxic stress. This study was designed to investigate the effects of melatonin on tumor growth and angiogenesis, as well as the mechanism underlying the antitumor activities of melatonin. In this study, we show that the administration of melatonin inhibits tumor growth and blocks tumor angiogenesis in mice. Moreover, melatonin diminished the expression of the HIF-1α protein within the tumor mass during tumorigenesis. Our findings suggest that melatonin is a promising anti-angiogenic therapeutic agent targeting HIF-1α in cancer. Considering that HIF-1α is overexpressed in a majority of human cancers, melatonin could offer a potent therapeutic agent for cancer.

The anti-angiogenic activities of glycyrrhizic acid in tumor progression

Glycyrrhizic acid (GA) is the bioactive compound of licorice and has been used as a herbal medicine because of its anti-viral, anti-cancer, and anti-inflammatory properties. This study was designed to investigate the effects of GA on tumor growth, angiogenesis, and the mechanisms underlying the anti-angiogenic activities of GA. We observed that GA inhibited tumor growth and angiogenesis in mice. GA decreased angiogenic activities, such as the migration, invasion, and tube formation of endothelial cells. We also demonstrated that GA reduced the production of reactive oxygen species and activation of ERK in endothelial cells. Our findings suggest that GA is a promising anti-angiogenic therapeutic agent that targets the ERK pathway. Considering that angiogenesis is highly stimulated in the majority of cancers, GA could offer a potent therapeutic agent for cancer.

Evaluation of the angiogenesis inhibitor KR-31831 in SKOV-3 tumor-bearing mice using (64)Cu-DOTA-VEGF(121) and microPET

KR-31831 ((2R,3R,4S)-6-amino-4-[N-(4-chloropheyl)-N-(1H-imidazol-2ylmethyl)amino]-3-hydroxyl-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran), an angiogenesis inhibitor, was evaluated in tumor-bearing mice using molecular imaging technology. Pre-treatment microPET images were acquired on SKOV-3 cell-implanted nude mice after injection with (64)Cu-DOTA-VEGF(121). KR-31831 (50 mg/kg) was then injected intraperitoneally into the treatment group (n=3), while injection vehicle was injected into the control (n=4) and blocking (n=3) groups. After injections occurred daily for 28 days, all groups of mice underwent post-treatment microPET imaging after injection with (64)Cu-DOTA-VEGF(121). The post-treatment images showed high tumor uptake in the control group and reduced tumor uptake in both the blocking and treatment groups. ROI analysis of the tumor images revealed 6.25%±1.18% ID/g at 1 h, 6.55%±0.69% ID/g at 2 h, and 4.68%±0.63% ID/g at 16 h in the control group; 3.87%±0.45% ID/g at 1 h, 4.50%±0.44% ID/g at 2 h, and 3.63%±0.25% ID/g at 16 h in the blocking group; and 4.03%±0.74% ID/g at 1 h, 4.37%±0.67% ID/g at 2 h, and 3.83%±0.90% ID/g at 16 h in the treatment group. Biodistribution obtained after the post-treatment microPET imaging also demonstrated high tumor uptake (3.74%±0.27% ID/g) in the control group and reduced uptakes in both the blocking group (2.69%±0.73% ID/g, P<.05) and the treatment group (3.11%±0.25% ID/g, P<.05), which correlated well with microPET imaging data. Immunofluorescence analysis showed higher levels of VEGFR2 and CD31 expressions in tumor tissues of the control and blocking groups than in tumor tissues of the treatment group. These results suggest that the antiangiogenic activity of KR-31831 is mediated through VEGFR2 and microPET serves as a useful molecular imaging tool for evaluation of a newly developed angiogenesis inhibitor, KR-31831.

Evaluation of antiangiogenic effects of a new synthetic candidate drug KR-31831 on xenografted ovarian carcinoma using dynamic contrast enhanced MRI

Objective

The purpose of this research was to investigate the anti-angiogenic inhibitory effect of KR-31831, a newly developed anti-angiogenic agent, on an in vivo human ovarian carcinoma model using dynamic contrast-enhanced (DCE) MRI.

Materials and Methods

Xenografted ovarian tumors were established by subcutaneous injection of SKOV3 cells into mice. The mice were treated daily with KR-31831 at 50 mg/kg for 21 days. Tumor tissues were excised corresponding to the DCE-MRI sections for evaluation of MVD with CD31 immunohistochemistry. All in vivo MRIs were performed on a 7.0 Tesla micro-MRI System. DCE-MRI was acquired prior to initiating treatment with KR-31831 and again on days 3 and 21 after treatment. The permeability parameters (K^trans, v_e, and v_p) were estimated using a pharmacokinetic model.

Results

Qualitatively, the K^trans parametric mapping showed different changes before and after treatment with KR-31831 in the treatment group. For quantification of this change, the median of K^trans values were compared before and after treatments in the control and KR-31831-treated groups. A non-parametric statistical test (Wilcoxon signed-rank test) showed decreasing K^trans values on day 21 compared to days 0 and 3 in the KR-31831-treated group (p < 0.05), whereas there was no significant difference in the control group (p = 0.84).

Conclusion

Our results suggest that DCE-MRI can be a useful tool by which to evaluate the anti-angiogenic effect of KR-31831 on a xenografted human ovarian carcinoma model.

Expression of Reversion-inducing Cysteine-rich Protein with Kazal Motifs in Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus: Links to Disease Activity, Damage Accrual and Matrix Metalloproteinase 9 Secretion

We studied the expression of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) on peripheral blood mononuclear cells (PBMCs), the serum concentration of matrix metalloproteinase 9 (MMP-9) and the MMP-9 secretion ability of PBMCs in patients with systemic lupus erythematosus (SLE), and clinical features were assessed. Compared with PBMCs from healthy donors, PBMCs from SLE patients expressed less RECK protein and mRNA but secreted more MMP-9. The serum concentration of MMP-9 was, however, lower in SLE patients than in healthy donors. The level of RECK protein was inversely associated with the Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI) and MMP-9 secretion in SLE, but no relationship was found between serum MMP-9 concentration and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). In conclusion, the level of RECK protein expressed in PBMCs could be used to predict organ or system damage in SLE and this might help in developing new therapies for SLE targeted at MMP-9.