Potentiometric multi-walled carbon nanotube Zn-sensor based on a naphthalocyanine neutral carrier: experimental and theoretical studies

Naphthalocyanine derivative is incorporated in carbon paste electrode and examined as a neutral carrier for zinc selective electrode.

Photocatalytic degradation of methylene blue with hematite nanoparticles synthesized by thermal decomposition of fluoroquinolones oxalato–iron(iii) complexes

Thermal decomposition of fluoroquinolones oxalato iron(iii) complexes, synthesized from fluoroquinolones and potassium tris(oxalato)ferrate(iii) trihydrate, gave α-Fe₂O₃ nanoparticles suitable for the photocatalytic degradation of methylene blue.

Elongation factor-2 kinase regulates TG2/β1 integrin/Src/uPAR pathway and epithelial-mesenchymal transition mediating pancreatic cancer cells invasion

Pancreatic ductal adenocarcinoma is one of the lethal cancers with extensive local tumour invasion, metastasis, early systemic dissemination and poorest prognosis. Thus, understanding the mechanisms regulating invasion/metastasis and epithelial-mesenchymal transition (EMT), is the key for developing effective therapeutic strategies for pancreatic cancer (PaCa). Eukaryotic elongation factor-2 kinase (eEF-2K) is an atypical kinase that we found to be highly up-regulated in PaCa cells. However, its role in PaCa invasion/progression remains unknown. Here, we investigated the role of eEF-2K in cellular invasion, and we found that down-regulation of eEF-2K, by siRNA or rottlerin, displays impairment of PaCa cells invasion/migration, with significant decreases in the expression of tissue transglutaminase (TG2), the multifunctional enzyme implicated in regulation of cell attachment, motility and survival. These events were associated with reductions in β1 integrin/uPAR/MMP-2 expressions as well as decrease in Src activity. Furthermore, inhibition of eEF-2K/TG2 axis suppresses the EMT, as demonstrated by the modulation of the zinc finger transcription factors, ZEB1/Snail, and the tight junction proteins, claudins. Importantly, while eEF-2K silencing recapitulates the rottlerin-induced inhibition of invasion and correlated events, eEF-2K overexpression, by lentivirus-based expression system, suppresses such rottlerin effects and potentiates PaCa cells invasion/migration capability. Collectively, our results show, for the first time, that eEF-2K is involved in regulation of the invasive phenotype of PaCa cells through promoting a new signalling pathway, which is mediated by TG2/β1 integrin/Src/uPAR/MMP-2, and the induction of EMT biomarkers which enhance cancer cell motility and metastatic potential. Thus, eEF-2K could represent a novel potential therapeutic target in pancreatic cancer.

Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: spectroscopic and quantum chemical studies

Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, (1)H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80°C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO(-)], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]⋅4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional.

Selective coordination ability of sulfamethazine Schiff-base ligand towards copper(II): molecular structures, spectral and SAR study

In the present work, a combined experimental and theoretical study of the N-(4,6-Dimethyl-pyrimidin-2-yl)-4-[(2-hydroxy-benzylidene)amino]benzenesulfonamide ligand (H2L) and its mononuclear and magnetically diluted binuclear Cu(II) complexes has been performed using IR, TG/DTA, magnetic, EPR, and conductivity measurements. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using the MPW1PW91 functional. Coordination of H2L to a Cu(II) center, regardless of the binding site and Cu:L stoichiometry, leads to a significant decrease in the antibacterial activity compared to the free ligand as well as reference drugs in the case of Staphylococcus aureus. Structural-activity relationship suggests that ELUMO, ΔE, dipole moment, polarizability and electrophilicity index were the most significant descriptors for the correlation with the antibacterial activity.

Targeting elongation factor-2 kinase (eEF-2K) induces apoptosis in human pancreatic cancer cells

Pancreatic cancer (PaCa) is one of the most aggressive, apoptosis-resistant and currently incurable cancers with a poor survival rate. Eukaryotic elongation factor-2 kinase (eEF-2K) is an atypical kinase, whose role in PaCa survival is not yet known. Here, we show that eEF-2K is overexpressed in PaCa cells and its down-regulation induces apoptotic cell death. Rottlerin (ROT), a polyphenolic compound initially identified as a PKC-δ inhibitor, induces apoptosis and autophagy in a variety of cancer cells including PaCa cells. We demonstrated that ROT induces intrinsic apoptosis, with dissipation of mitochondrial membrane potential (ΔΨm), and stimulates extrinsic apoptosis with concomitant induction of TNF-related apoptosis inducing ligand (TRAIL) receptors, DR4 and DR5, with caspase-8 activation, in PANC-1 and MIAPaCa-2 cells. Notably, while none of these effects were dependent on PKC-δ inhibition, ROT down-regulates eEF-2K at mRNA level, and induce eEF-2K protein degradation through ubiquitin-proteasome pathway. Down-regulation of eEF-2K recapitulates the events observed after ROT treatment, while its over-expression suppressed the ROT-induced apoptosis. Furthermore, eEF-2K regulates the expression of tissue transglutaminase (TG2), an enzyme previously implicated in proliferation, drug resistance and survival of cancer cells. Inhibition of eEF-2K/TG2 axis leads to caspase-independent apoptosis which is associated with induction of apoptosis-inducing factor (AIF). Collectively, these results indicate, for the first time, that the down-regulation of eEF-2K leads to induction of intrinsic, extrinsic as well as AIF-dependent apoptosis in PaCa cells, suggesting that eEF-2K may represent an attractive therapeutic target for the future anticancer agents in PaCa.

Crystal structure, DFT, spectroscopic and biological activity evaluation of analgin complexes with Co(ii), Ni(ii) and Cu(ii)

Coordination of analgin to Ni(ii) and Cu(ii) ions as a mono-negatively tridentate ligand leads to a significant increase in its antibacterial activity compared with the Co(ii) complex.

Wogonin attenuates etoposide-induced oxidative DNA damage and apoptosis via suppression of oxidative DNA stress and modulation of OGG1 expression

Damage to DNA can lead to many different acute and chronic pathophysiological conditions, ranging from cancer to endothelial damage. The current study has been initiated to determine whether the flavonoid wogonin can attenuate etoposide-induced oxidative DNA damage and apoptosis in mouse bone marrow cells. We found that oral administration of wogonin before etoposide injection significantly attenuates etoposide-induced oxidative DNA damage and apoptosis in a dose dependent manner. Etoposide induced a significant down-regulation of mRNA expression of the OGG1 repair gene and marked biochemical alterations characteristic of oxidative DNA stress, including increased 8-OHdG, enhanced lipid peroxidation and reduction in reduced glutathione. Prior administration of wogonin ahead of etoposide challenge restored these altered parameters. Importantly, wogonin had no antagonizing effect on etoposide-induce topoisomerase-II inhibition. Conclusively, our study indicates that wogonin has a protective role in the abatement of etoposide-induced oxidative DNA damage and apoptosis in the bone marrow cells of mice via suppression of oxidative DNA stress and enhancing DNA repair through modulation of OGG1 repair gene expression. Therefore, wogonin can be a promising chemoprotective agent and might be useful to avert secondary leukemia and other drug-related cancers in cured cancer patients and medical personnel exposing to the potent carcinogen etoposide.

Abstract 848: Inhibition of eukaryotic elongation factor-2 kinase mediates Rottlerin induced effects in apoptosis and cell proliferation inhibition in human pancreatic cancer cells

Pancreatic cancer (PaCa) is one of the most aggressive cancers and currently incurable with less than 2% five-years survival rate. Among the ever-increasing list of naturally occurring anticancer agents, a Kmala Tree-derived anticancer compound, Rottlerin (ROT), a PKC-delta inhibitor, appears to have anti-proliferative activity due to its effects on several pathways and cell machineries involved in cell survival, apoptosis, autophagy and invasion. Recent studies suggest that ROT is not a specific PKC delta inhibitor and mediates its effects through other mechanisms. We have previously reported that inhibition of eukaryotic elongation factor-2 kinase (eEF-2K), one of the major kinases appears to be activated in rapidly proliferating malignant cells, leads to down-regulation of signaling pathways affecting growth, survival and chemotherapeutic resistance (Tekedereli et al, 2012). Thus, we hypothesized that ROT targets eEF-2K, and inhibition of eEF-2K signaling is responsible of mediating its effects in PaCa cells. We found that ROT treatment (4-10 μM) inhibits the expression of eEF-2K that was associated with apoptosis induction in PaCa cells in a dose and time-dependent manner as detected by Western blot analysis. We also found that ROT treatment inhibits PaCa cell proliferation and mitochondrial activity and modulates G1/S phase progression in these cells. Treating PaCa cells with ROT markedly induced expression of active caspase-9, caspase-3 and cleaved PARP. To demonstrate a direct link between eEF-2K inhibition and ROT-induced effects, we knocked-down eEF-2K by a specific siRNA. Such knockdown was associated with inhibition of cell growth, resulted in modulation of caspase-related events with induction of similar degree of apoptosis, increased the percentage of Annexin V positive apoptotic cells and resulted in induction of cellular shrinkage and blebbing. Moreover, we found that eEF-2K down-regulation is involved in ROT-induced stimulation of extrinsic apoptotic pathway in PaCa cells with concomitant induction of TNF related apoptosis inducing ligand (TRAIL) receptor DR4 and caspase-8 cleavage. In addition, our findings suggest that eEF-2K contributes to the regulation of G1/S phase progression, as in vitro down-modulation eEF-2K resulted in an increase in the expression of p27Kip1 cyclin-dependent kinase inhibitor (CDKI). Collectively, the results of our study demonstrate, for the first time, that down-regulation of eEF-2K contributes to rottlerin-induced effects including, growth inhibition and apoptosis in PaCa cells and clearly demonstrate novel mechanisms of ROT-induced potent antitumor effects. These findings show that the multi-targeted kinase inhibitor, ROT, represents a promising novel agent for PaCa treatment and eEF-2K could represent an attractive target for the future anticancer agents.

Citation Format: Ahmed A. Ashour, Abdel-Aziz H. Abdel-Aziz, Ahmed M. Mansour, Sultan N. Alpay, Kevin Dalby, Bulent Ozpolat. Inhibition of eukaryotic elongation factor-2 kinase mediates Rottlerin induced effects in apoptosis and cell proliferation inhibition in human pancreatic cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 848. doi:10.1158/1538-7445.AM2013-848

Novel Ni(II) and Zn(II) complexes coordinated by 2-arylaminomethyl-1H-benzimidazole: molecular structures, spectral, DFT studies and evaluation of biological activity

[NiL(1,2)Cl(2)(OH(2))(3)]·zH(2)O and [ZnL(1,2)(CH(3)CO(2))(2)] (L(1)=(1H-benzimidazol-2-ylmethyl)-N-phenyl amine, z=0 and L(2)=2-[(1H-Benzimidazol-2-ylmethyl)-amino]-benzoic acid methyl ester, z=1) complexes have been synthesized and characterized by a variety of physico-chemical techniques. The central Ni(II) ion is coordinated by only the pyridine-type nitrogen (N(py)) of benzimidazole ring, three water molecules and two chlorido ligands forming a distorted octahedral geometry. Five coordinated zinc complexes were obtained, where the coordination sphere of zinc ion is made up of secondary amino group (NH(sec)), N(py) and two acetate groups, one acts as a unidentate and the other as a bidentate. A theoretical DFT/UB3LYP method combined with LANL2DZ basis set shows that all the metal-ligand bonds are of the L→M type. Electronic structures have been calculated using TD-DFT method. The antibacterial activity of NiL(2) complexes decreases by the introduction of COOCH(3) group in the ortho-position of the aniline moiety.

Diffuse large B cell lymphoma of the spermatic cord: a case report and literature review

Primary lymphoma of the spermatic cord is rare. We report a case of primary lymphoma of the spermatic cord and review the literature. A 77-year-old man presented with a 5 month history of an enlarging right inguino-scrotal mass. On physical exam, the mass involved the spermatic cord. Computerized tomography and magnetic resonance imaging revealed a 10 cm x 4 cm inguinoscrotal mass related to the spermatic cord. A right inguinal orchidectomy with wide local excision was performed. Pathological and immunohistochemical evaluation identified the tumor as a diffuse large B cell lymphoma of the spermatic cord. Postoperatively, patient began a chemoradiotherapy regimen consistent with metastatic lymphoma.

Molecular structures of 2-arylaminomethyl-1H-benzimidazole: spectral, electrochemical, DFT and biological studies

In the present work, structural studies on (1H-benzimidazol-2-ylmethyl)-N-(4-chloro-phenyl)-amine (L(1)) and (1H-benzimidazol-2-ylmethyl)-N-(4-iodo-phenyl)-amine (L(2)) have been done extensively by a variety of physico-chemical techniques. Optimized geometrical structures, harmonic vibrational frequencies, natural bonding orbital (NBO) analysis, and Frontier molecular orbitals (FMO) were obtained by DFT/B3LYP method. TD-DFT calculations help to assign the electronic transitions. The polarizable continuum model (PCM) fails to describe the experimental chemical shift associated with the NH protons as calculated by applying Gauge-invariant atomic orbital (GIAO) method, but a very good correlation between the theoretical and experimental values was achieved by taking into account the specific solute-solvent interactions. DFT calculations showed a good agreement between the theoretical and observed results. These compounds exhibited a high biological activity through the inhibition of the metabolic growth of the investigated bacteria.