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Six dinuclear lanthanide(III) nitrato complexes [Ln(NO3)3(H2O)]2(µ-tppz) (where tppz = 2,3,5,6-tetra(2-pyridyl) pyrazine and Ln(III) = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), and Dy (6)) with bis-tridentate N-heterocyclic 2,3,5,6-tetra(2-pyridyl)pyrazine as bridging ligand have been solvothermally synthesized and characterized via elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction, and powder X-ray diffraction. The 3-D Hirshfeld surface and 2-D fingerprint plots show that the main interactions in 1-6 are the O⋯H/H⋯O intermolecular interactions with relative contributions of about 62%. Although the poor lanthanide(III)-centered luminescence properties clearly point to the efficiency of nonradiative quenching processes (presence of water molecules in the coordination sphere of the lanthanide(III) ions), the ligand tppz is better suited to sensitize the lanthanide(III)'s emissions of EuIII and NdIII than SmIII, TbIII, and DyIII. Finally, the magnetic data of DyIII comple×6 reveals antiferromagnetic coupling between DyIII ions.

RESUMEN

Four mononuclear lanthanide complexes containing 4'-phenyl-2,2':6',2″-terpyridine (ptpy), [Ln(NO3)3(ptpy) (H2O)] (Ln = Eu (1), Gd (2), Tb (3), Dy (4)), were solvothermally synthesized and characterized via elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction, and powder X-ray diffraction. Hirshfeld surfaces and the solid-state luminescence properties of the complexes were investigated. The 3-D Hirshfeld surface and 2-D fingerprint plots show that the main interactions are the O H/H O intermolecular interactions in 1-4. Solid-state luminescence investigation reveals that GdIII complex 2 displays a ligand-centered emission and the EuIII, TbIII and DyIII complexes 1, 3 and 4 show the characteristic lanthanide-centered luminescence upon UV excitations. The EuIII and TbIII complexes exhibit red (CIE: 0.6549, 0.3447) and green (CIE: 0.3760, 0.5412) luminescence in the solid state with quantum yields of 16.8% and 0.8% and lifetimes of 0.545 and 0.043 ms, respectively. Density functional theory (DFT) calculations were conducted to unravel the HOMO-LUMO energy gaps of the structures of ptpy and complexes 1 and 3.

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In this study, we introduced a new strategy, feeding D-glucose, to overproduce extracellular 5-aminolevulinic acid (ALA) in the recombinant Escherichia coli. We investigated that the D-glucose concentration is dependent on extracellular ALA production. The results indicated that increasing D-glucose concentration in bacteria culture enhanced final cell density and ALA yield and simultaneously decreased the activities of ALA synthase (ALAS) and ALA dehydratase (ALAD); then, the inhibitory effect of D-glucose on ALAS activity was relieved with the metabolism of D-glucose. when 4.0 g/L D-glucose was added at late exponential phase; 1.46 g/L ALA was achieved in shaking culture, which is 47% or 109% higher than the ALA yields with 30 mM levulinic acid of ALAD inhibitor or no inhibitor. In jar fermenter, final extracellular ALA concentration reached 3.1 g/L by feeding with D-glucose.

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The erbB-2 gene encodes tyrosine kinase receptor p185(neu). Overexpression of erbB-2 plays a key role in tumorigenesis and the progression of tumors such as breast cancer and ovarian cancer. Our investigation suggests that the anti-inflammatory agent N-(4-ethoxyphenol)-2-hydroxy-acid amide (SUCI02) reversibly represses tyrosine phosphorylation of erbB-2 in a dose-dependent manner, with half maximal inhibition occurring at a concentration of 21.05 micromol/L without reduced erbB-2 receptor expression. Activation of mitogen-activated protein kinase and protein kinase B, downstream molecules of the erbB-2-mediated signal transduction pathway, was inhibited following exposure to SUCI02. In contrast, tyrosine phosphorylation of epidermal growth factor receptor (EGFR) was relatively unaffected by SUCI02. Proliferation of erbB-2-overexpressing BT474 cells was inhibited to a greater extent than proliferation of EGFR-overexpressing A431 cells following exposure to SUCI02. SUCI02 induced cell cycle arrest in G(1) phase with upregulation of p27 and downregulation of pRb phosphorylation. Systemic administration of SUCI02 in nude mice resulted in inhibition of erbB-2 tyrosine kinase phosphorylation of subcutaneous human breast cancer BT474 xenografts. We conclude that SUCI02 inhibits erbB-2 tyrosine kinase phosphorylation in vitro and in vivo, shuts down the erbB-2 downstream pathway and induces cell cycle arrest in G(1) phase. These results suggest that SUCI02 is a potential novel anticancer agent that deserves further investigation. (Cancer Sci 2006; 97: 84-89).

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BACKGROUND & OBJECTIVE: Overexpression of HER-2/neu receptor plays a key role in tumorigenesis,progression,prognosis and chemosensitivity of tumors. We found that SUCI02[N-(4-ethoyphenol)-2-hydroxy- acid amide] could inhibit HER2/neu phosphorylation through comprehensive screening. The aim of this study was to examine the effect of SUCI02 on HER-2/neu-overexpressing cancer cell growth. METHODS: Western blot analysis and immunoprecipitation was used to examine the changes of HER-2/neu receptor tyrosine kinase phosphorylation and protein level. MTT assay was employed to determine the growth inhibition of SUCI02 on the tumor cells. RESULTS: SUCI02 reversibly inhibited tyrosine phosphorylation of HER-2/neu in a dose-dependent manner with half maximal inhibition at a concentration of 4.34 microg/ml without reduced HER-2/neu receptor protein expression. Activation of MAPK and AKT, which were downstream molecules of HER-2/neu-mediated signal transduction pathway, was inhibited after being exposure to SUCI02. In contrast, tyrosine phosphorylation of EGFR was relatively unaffected at the concentrations of SUCI02 up to 40 microg/ml. SUCI02 inhibited cell proliferation of HER-2/neu- overexpressing MDA-MB-453m1 more potent than that of EGFR-overexpressing MDA-MB-468.Their IC(50) values were 1.33 microg/ml and 11.3 microg/ml,respectively. CONCLUSION: SUCI02 can inhibit tyrosine phosphorylation of HER-2/neu receptor,cell proliferation of HER-2/neu-overexpressing breast cancer cells preferentially and shut down downstream HER-2/neu signal transduction.

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