Site-specific DNA oxidation by a dinuclear copper complex containing a photoisomerizable azobenzene ligand

A dinuclear copper complex possessing an azobenzene backbone (Cu^[II]_[2]1) was synthesized and its affinity towards DNA was investigated and found to be dependent on the trans–cis isomeric forms. Upon exposure to UV light at 365 nm the trans form of the complex (Cu^[II]_[2]trans-1) underwent photoisomerization into the cis-isomer (Cu^[II]_[2]cis-1), which reverted to the original trans-form on exposure to visible light at 420 nm. Both thetrans and cis isomers exhibited moderate DNA cleavage activity toward plasmid duplex DNA in the presence of a reducing agent 3-mercaptopropionic acid (MPA) suggesting that the Cu^[I] species could activate molecular oxygen to form a reactive oxygen species in situ. Interestingly, the isomeric copper complexes showed different site-specificities in the oxidation of an oligodeoxynucleotide having single-strand–double-helix junctions in the sequence. The trans isomer Cu^[I]_[2]trans-1 induced oxidation at the consecutive deoxyguanosine site (GG) near the junction; on the other hand, such site-specificity was not observed in the case of Cu^[I]_[2]cis-1

Increase of nitrosative stress in patients with eosinophilic pneumonia

<p>Abstract</p> <p>Background</p> <p>Exhaled nitric oxide (NO) production is increased in asthma and reflects the degree of airway inflammation. The alveolar NO concentration (Calv) in interstitial pneumonia is reported to be increased. However, it remains unknown whether NO production is increased and nitrosative stress occurs in eosinophilic pneumonia (EP). We hypothesized that nitrosative stress markers including Calv, inducible type of NO synthase (iNOS), and 3-nitrotyrosine (3-NT), are upregulated in EP.</p> <p>Methods</p> <p>Exhaled NO including fractional exhaled NO (FE_NO) and Calv was measured in ten healthy subjects, 13 patients with idiopathic pulmonary fibrosis (IPF), and 13 patients with EP. iNOS expression and 3-NT formation were assessed by immunocytochemistory in BALf cells. The exhaled NO, lung function, and systemic inflammatory markers of the EP patients were investigated after corticosteroid treatment for 4 weeks.</p> <p>Results</p> <p>The Calv levels in the EP group (14.4 ± 2.0 ppb) were significantly higher than those in the healthy subjects (5.1 ± 0.6 ppb, p < 0.01) and the IPF groups (6.3 ± 0.6 ppb, p < 0.01) as well as the FE_NOand the corrected Calv levels (all p < 0.01). More iNOS and 3-NT positive cells were observed in the EP group compared to the healthy subject and IPF patient. The Calv levels had significant positive correlations with both iNOS (r = 0.858, p < 0.05) and 3-NT positive cells (r = 0.924, p < 0.01). Corticosteroid treatment significantly reduced both the FE_NO(p < 0.05) and the Calv levels (p < 0.01). The magnitude of reduction in the Calv levels had a significant positive correlation with the peripheral blood eosinophil counts (r = 0.802, p < 0.05).</p> <p>Conclusions</p> <p>These results suggested that excessive nitrosative stress occurred in EP and that Calv could be a marker of the disease activity.</p

Raloxifene inhibits tumor growth and lymph node metastasis in a xenograft model of metastatic mammary cancer

<p>Abstract</p> <p>Background</p> <p>The effects of raloxifene, a novel selective estrogen receptor modulator, were studied in a mouse metastatic mammary cancer model expressing cytoplasmic ERα.</p> <p>Methods</p> <p>Mammary tumors, induced by inoculation of syngeneic BALB/c mice with BJMC3879luc2 cells, were subsequently treated with raloxifene at 0, 18 and 27 mg/kg/day using mini-osmotic pumps.</p> <p>Results</p> <p><it>In vitro </it>study demonstrated that the ERα in BJMC3879luc2 cells was smaller (between 50 and 64 kDa) than the normal-sized ERα (66 kDa) and showed cytoplasmic localization. A statistically significant but weak estradiol response was observed in this cell line. When BJMC3879luc2 tumors were implanted into mice, the ERα mRNA levels were significantly higher in females than in males. <it>In vitro </it>studies showed that raloxifene induced mitochondria-mediated apoptosis and cell-cycle arrest in the G1-phase and a decrease in the cell population in the S-phase. In animal experiments, tumor volumes were significantly suppressed in the raloxifene-treated groups. The multiplicity of lymph node metastasis was significantly decreased in the 27 mg/kg group. Levels of apoptosis were significantly increased in the raloxifene-treated groups, whereas the levels of DNA synthesis were significantly decreased in these groups. No differences in microvessel density in tumors were observed between the control and raloxifene-treated groups. The numbers of dilated lymphatic vessels containing intraluminal tumor cells were significantly reduced in mammary tumors in the raloxifene-treated groups. The levels of ERα mRNA in mammary tumors tended to be decreased in the raloxifene-treated groups.</p> <p>Conclusion</p> <p>These results suggest that the antimetastatic activity of raloxifene in mammary cancer expressing cytoplasmic ERα may be a crucial finding with clinical applications and that raloxifene may be useful as an adjuvant therapy and for the chemoprevention of breast cancer development.</p

α-Mangostin extracted from the pericarp of the mangosteen (Garcinia mangostana Linn) reduces tumor growth and lymph node metastasis in an immunocompetent xenograft model of metastatic mammary cancer carrying a p53 mutation

<p>Abstract</p> <p>Background</p> <p>The mangosteen fruit has a long history of medicinal use in Chinese and Ayurvedic medicine. Recently, the compound α-mangostin, which is isolated from the pericarp of the fruit, was shown to induce cell death in various types of cancer cells in <it>in vitro </it>studies. This led us to investigate the antitumor growth and antimetastatic activities of α-mangostin in an immunocompetent xenograft model of mouse metastatic mammary cancer having a p53 mutation that induces a metastatic spectrum similar to that seen in human breast cancers.</p> <p>Methods</p> <p>Mammary tumors, induced by inoculation of BALB/c mice syngeneic with metastatic BJMC3879luc2 cells, were subsequently treated with α-mangostin at 0, 10 and 20 mg/kg/day using mini-osmotic pumps and histopathologically examined. To investigate the mechanisms of antitumor ability by α-mangostin, <it>in vitro </it>studies were also conducted.</p> <p>Results</p> <p>Not only were <it>in vivo </it>survival rates significantly higher in the 20 mg/kg/day α-mangostin group versus controls, but both tumor volume and the multiplicity of lymph node metastases were significantly suppressed. Apoptotic levels were significantly increased in the mammary tumors of mice receiving 20 mg/kg/day and were associated with increased expression of active caspase-3 and -9. Other significant effects noted at this dose level were decreased microvessel density and lower numbers of dilated lymphatic vessels containing intraluminal tumor cells in mammary carcinoma tissues.</p> <p><it>In vitro</it>, α-mangostin induced mitochondria-mediated apoptosis and G1-phase arrest and S-phase suppression in the cell cycle. Since activation by Akt phosphorylation plays a central role in a variety of oncogenic processes, including cell proliferation, anti-apoptotic cell death, angiogenesis and metastasis, we also investigated alterations in Akt phosphorylation induced by α-mangostin treatment both <it>in vitro </it>and <it>in vivo</it>. Quantitative analysis and immunohistochemistry showed that α-mangostin significantly decreased the levels of phospho-Akt-threonine 308 (Thr308), but not serine 473 (Ser473), in both mammary carcinoma cell cultures and mammary carcinoma tissues <it>in vivo</it>.</p> <p>Conclusions</p> <p>Since lymph node involvement is the most important prognostic factor in breast cancer patients, the antimetastatic activity of α-mangostin as detected in mammary cancers carrying a p53 mutation in the present study may have specific clinical applications. In addition, α-mangostin may have chemopreventive benefits and/or prove useful as an adjuvant therapy, or as a complementary alternative medicine in the treatment of breast cancer.</p

Left Atrial Ball-Shaped Thrombus with Concomitant Biatrial Appendage Thrombi in a Patient with Prior Mitral Valve Replacement

We reported a 67-year-old woman in whom large atrial thrombi were found by chance during discontinuation of therapeutic anticoagulation. The patient, with a history of mitral valve replacement surgery, had stopped anticoagulation for months because of intractable gastrointestinal bleeding, during which she was found to have 3 large thrombi in the atria on transesophageal echocardiography: left atrial free-floating ball-shaped thrombus, left atrial appendage thrombus, and right atrial appendage thrombus. One month following diagnosis, she still had the free-floating thrombus despite adequate anticoagulation. Free-floating ball-shaped thrombus is a rare finding observed on echocardiography in patients with mitral valve disease and an even rarer finding in case of appendage thrombi coexisting

αvβ3-Integrin-targeting lanthanide complex: synthesis and evaluation as a tumor-homing luminescent probe.

The application of lanthanide complexes in the time-resolved fluorescence imaging of living cells has emerged in the last few decades, providing high-contrast images of cells through detection of the delayed emission. In the present study, we synthesized novel trivalent lanthanide complexes containing the cyclic peptide c(RGDfK) to visualize the α(v)β(3)-integrin-expressing tumor cells. Conjugation of c(RGDfK) with the macrocyclic bipyridine ligand had little effect on the fluorescence properties of the complex, indicating that the coordinated lanthanide ion was well isolated from the peptide. Bright luminescence images of α(v)β(3)-integrin-expressing U87-MG cells were successfully obtained by employing the probes

Site-specific DNA oxidation by a dinuclear copper complex containing a photoisomerizable azobenzene ligand

A dinuclear copper complex possessing an azobenzene backbone (Cu^[II]_[2]1) was synthesized and its affinity towards DNA was investigated and found to be dependent on the trans–cis isomeric forms. Upon exposure to UV light at 365 nm the trans form of the complex (Cu^[II]_[2]trans-1) underwent photoisomerization into the cis-isomer (Cu^[II]_[2]cis-1), which reverted to the original trans-form on exposure to visible light at 420 nm. Both thetrans and cis isomers exhibited moderate DNA cleavage activity toward plasmid duplex DNA in the presence of a reducing agent 3-mercaptopropionic acid (MPA) suggesting that the Cu^[I] species could activate molecular oxygen to form a reactive oxygen species in situ. Interestingly, the isomeric copper complexes showed different site-specificities in the oxidation of an oligodeoxynucleotide having single-strand–double-helix junctions in the sequence. The trans isomer Cu^[I]_[2]trans-1 induced oxidation at the consecutive deoxyguanosine site (GG) near the junction; on the other hand, such site-specificity was not observed in the case of Cu^[I]_[2]cis-1