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Full-Text Articles in Chemistry

The Association Of Elevated 2′,5′-Oligoadenylate-Dependent Rnase L With Lung Cancer Correlated With Deficient Enzymatic Activity And Decreased Capacity Of Rnase L Dimerization, Huijing Yin, Aimin Zhou, Yalei Dai Oct 2012

The Association Of Elevated 2′,5′-Oligoadenylate-Dependent Rnase L With Lung Cancer Correlated With Deficient Enzymatic Activity And Decreased Capacity Of Rnase L Dimerization, Huijing Yin, Aimin Zhou, Yalei Dai

Chemistry Faculty Publications

RNase L mediates critical cellular functions including antiviral, proapoptotic, antiproliferative and tumor suppressive activities. In this study, the expression and function of RNase L in lung cancer cells were examined. Interestingly we have found that the expression of RNase L in lung cancer cells was 3- and 9-fold higher in its mRNA and protein levels, but a significant decrease of its enzymatic activity when compared to that in corresponding normal lung cells. Further investigation revealed that 2-5A-induced dimerization of the RNase L protein, a necessary prerequisite for activation of RNase L, was inhibited, as a result of that RLI, a …


Cox Inhibitors Indomethacin And Sulindac Derivatives As Antiproliferative Agents: Synthesis, Biological Evaluation, And Mechanism Investigation, Snigdha Chennamaneni, Bo Zhong, Rati Lama, Bin Su Oct 2012

Cox Inhibitors Indomethacin And Sulindac Derivatives As Antiproliferative Agents: Synthesis, Biological Evaluation, And Mechanism Investigation, Snigdha Chennamaneni, Bo Zhong, Rati Lama, Bin Su

Chemistry Faculty Publications

Cyclooxygenase (COX) inhibitors Indomethacin and its structural analogs Sulindac exhibit cell growth inhibition and apoptosis inducing activities in various cancer cell lines via COX independent mechanisms. In this study, the molecular structures of Indomethacin and Sulindac were used as starting scaffolds to design novel analogs and their effects on the proliferation of human cancer cells were evaluated. Compared to Indomethacin and Sulindac inhibiting cancer cell proliferation with IC50s of more than 1 mM, the derivatives displayed significantly increased activities. Especially, one of the Indomethacin analogs inhibited the growth of a series of cancer cell lines with IC50s around 0.5 μM–3 …


Exploring The Role Of A Conserved Class A Residue In The Ω-Loop Of Kpc-2 Β-Lactamase: A Mechanism For Ceftazidime Hydrolysis Sep 2012

Exploring The Role Of A Conserved Class A Residue In The Ω-Loop Of Kpc-2 Β-Lactamase: A Mechanism For Ceftazidime Hydrolysis

Chemistry Faculty Publications

Gram-negative bacteria harboring KPC-2, a class A β-lactamase, are resistant to all β-lactam antibiotics and pose a major public health threat. Arg-164 is a conserved residue in all class A β-lactamases and is located in the solvent-exposed Ω-loop of KPC-2. To probe the role of this amino acid in KPC-2, we performed site-saturation mutagenesis. When compared with wild type, 11 of 19 variants at position Arg-164 in KPC-2 conferred increased resistance to the oxyimino-cephalosporin, ceftazidime (minimum inhibitory concentration; 32→128 mg/liter) when expressed in Escherichia coli. Using the R164S variant of KPC-2 as a representative β-lactamase for more detailed analysis, we …


Identification Of Selective Tubulin Inhibitors As Potential Anti-Trypanosomal Agents, Rati Lama, Ranjodh Sandhu, Bo Zhong, Bibo Li, Bin Su Sep 2012

Identification Of Selective Tubulin Inhibitors As Potential Anti-Trypanosomal Agents, Rati Lama, Ranjodh Sandhu, Bo Zhong, Bibo Li, Bin Su

Chemistry Faculty Publications

The potency of a series of sulfonamide tubulin inhibitors against the growth of Trypanosoma brucei (T. brucei), as well as human cancer and primary fibroblast cells were evaluated with the aim of determining whether compounds that selectively inhibit parasite proliferation could be identified. Several compounds showed excellent selectivity against T. brucei growth, and have the potential to be used for the treatment of Human African trypanosomiasis. A T. brucei tubulin protein homology model was built based on the crystal structure of the bovine tubulin. The colchicine-binding domain, which is also the binding site of the tested sulfonamide tubulin inhibitors, showed …


Rnase L Controls Terminal Adipocyte Differentiation, Lipids Storage And Insulin Sensitivity Via Chop10 Mrna Regulation, O. Fabre, T. Salehzada, K. Lambert, Y. Boo Seok, Aimin Zhou, J. Mercier, C. Bisbal Sep 2012

Rnase L Controls Terminal Adipocyte Differentiation, Lipids Storage And Insulin Sensitivity Via Chop10 Mrna Regulation, O. Fabre, T. Salehzada, K. Lambert, Y. Boo Seok, Aimin Zhou, J. Mercier, C. Bisbal

Chemistry Faculty Publications

Adipose tissue structure is altered during obesity, leading to deregulation of whole-body metabolism. Its function depends on its structure, in particular adipocytes number and differentiation stage. To better understand the mechanisms regulating adipogenesis, we have investigated the role of an endoribonuclease, endoribonuclease L (RNase L), using wild-type and RNase L-knockout mouse embryonic fibroblasts (RNase L−/−-MEFs). Here, we identify C/EBP homologous protein 10 (CHOP10), a dominant negative member of the CCAAT/enhancer-binding protein family, as a specific RNase L target. We show that RNase L is associated with CHOP10 mRNA and regulates its stability. CHOP10 expression is conserved in RNase …


Development And Validation Of A Rapid Lc-Ms/Ms Method Fortthe Determination Of Jcc76, A Novel Antitumor Agent For Breast Cancer, In Rat Plasma And Its Application To A Pharmacokinetics Study, Xiaohan Cai, Bo Zhong, Bin Su, Songlin Xu, Baochuan Guo Sep 2012

Development And Validation Of A Rapid Lc-Ms/Ms Method Fortthe Determination Of Jcc76, A Novel Antitumor Agent For Breast Cancer, In Rat Plasma And Its Application To A Pharmacokinetics Study, Xiaohan Cai, Bo Zhong, Bin Su, Songlin Xu, Baochuan Guo

Chemistry Faculty Publications

JCC76 is a novel nimesulide analog that selectively inhibits the human epidermal growth factor receptor 2 (HER2) overexpressing breast cancer cell proliferation and tumor progression. To support further pharmacological and toxicological studies of JCC76, a novel and rapid method using liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed and validated for the quantification of the compound in rat plasma. A C18 column was used for chromatographic separation, and the mobile phase was aqueous ammonium formate (pH 3.7; 5 mm)–methanol (1:9, v/v) with an isocratic elution. With a simple liquid–liquid extraction procedure using the mixture of methyl …


Understanding The Molecular Determinants Of Substrate And Inhibitor Specificities In The Carbapenemase Kpc-2: Exploring The Roles Of Arg220 And Glu276 Aug 2012

Understanding The Molecular Determinants Of Substrate And Inhibitor Specificities In The Carbapenemase Kpc-2: Exploring The Roles Of Arg220 And Glu276

Chemistry Faculty Publications

β-Lactamases are important antibiotic resistance determinants expressed by bacteria. By studying the mechanistic properties of β-lactamases, we can identify opportunities to circumvent resistance through the design of novel inhibitors. Comparative amino acid sequence analysis of class A β-lactamases reveals that many enzymes possess a localized positively charged residue (e.g., R220, R244, or R276) that is critical for interactions with β-lactams and β-lactamase inhibitors. To better understand the contribution of these residues to the catalytic process, we explored the roles of R220 and E276 in KPC-2, a class A β-lactamase that inactivates carbapenems and β-lactamase inhibitors. Our study reveals that substitutions …


Development And Validation Of An Lc–Ms/Ms Method For Pharmacokinetic Study Of Methoxyamine In Phase I Clinical Trial, Shuming Yang, Panayiotis Savvides, Lili Liu, Stanton L. Gerson, Yan Xu Jul 2012

Development And Validation Of An Lc–Ms/Ms Method For Pharmacokinetic Study Of Methoxyamine In Phase I Clinical Trial, Shuming Yang, Panayiotis Savvides, Lili Liu, Stanton L. Gerson, Yan Xu

Chemistry Faculty Publications

Methoxyamine (MX) is the first DNA base-excision-repair (BER) inhibitor evaluated in humans. This work described the development and validation of an LC–MS/MS method for quantitative determination of MX in human plasma. In this method, MX and its stable isotope methoxyl-d3-amine (MX-d3 as internal standard) were directly derivatized in human plasma with 4-(N,N-diethylamino)benzaldehyde. The derivatized MX and IS were extracted by methyl-tert-butyl ether, and separated isocratically on a Xterra C18 column (2.1 mm × 100 mm) using an aqueous mobile phase containing 45% acetonitrile and 0.4% formic acid at a flow rate of 0.200 ml/min. Quantitation of MX was carried out …


6-Hydroximino-4-Aza-A-Homo-Cholest-3-One And Related Analogue As A Potent Inducer Of Apoptosis In Cancer Cells, Yanmin Huang, Jianguo Cui, Qiaoxia Zheng, Chun Zeng, Quan Chen, Aimin Zhou Jul 2012

6-Hydroximino-4-Aza-A-Homo-Cholest-3-One And Related Analogue As A Potent Inducer Of Apoptosis In Cancer Cells, Yanmin Huang, Jianguo Cui, Qiaoxia Zheng, Chun Zeng, Quan Chen, Aimin Zhou

Chemistry Faculty Publications

Here we report that 6-hydroximino-4-aza-A-homo-cholest-3-one and 6-hydroxyl-4-aza-A-homo-cholest-3-one, new steroidal lactams were synthesized recently, displayed antiproliferative activity against some cancer cells through inducing cancer cell apoptosis by activation of the intrinsic pathway. The apoptotic function of the compounds was demonstrated by release of cytochrome C, activation of caspase 3 and annexin V labeling. Furthermore, the compound was able to inhibit tumor growth in an athymic mouse model.


Maxwell's Equations, Part Vii, David W. Ball Jun 2012

Maxwell's Equations, Part Vii, David W. Ball

Chemistry Faculty Publications

This is the seventh (and perhaps last) installment of a series of columns on Maxwell’s equations of electrodynamics. In previous columns (available at Spectroscopy’s website, www.spectroscopyonline.com/The+Baseline+Column), we have covered history, the background of the first three equations, and the mathematics underlying them. Here we will present the fourth equation, and after reaching it we’ll see how light is described in terms of these four mathematical expressions.


Human Sperm Dna Oxidation, Motility And Viability In The Presence Of L-Carnitine During In Vitro Incubation And Centrifugation, S. Banihani, R. Sharma, Mekki Bayachou, E. Sabanegh, A. Agarwal May 2012

Human Sperm Dna Oxidation, Motility And Viability In The Presence Of L-Carnitine During In Vitro Incubation And Centrifugation, S. Banihani, R. Sharma, Mekki Bayachou, E. Sabanegh, A. Agarwal

Chemistry Faculty Publications

In vitro incubation and centrifugation is known to decrease human sperm quality. In the human body, besides its antioxidant effects, l-carnitine (LC) facilitates the transport of activated fatty acids from the cytosol to the mitochondrial matrix. In this study, we investigated the effect of LC on human sperm motility, viability and DNA oxidation after incubation and centrifugation, following the sperm preparation protocols of assisted reproduction. Normozoospermic semen samples (n = 55) were analysed according to the World Health Organization (WHO) guidelines. LC concentrations that are not toxic to spermatozoa as determined by sperm motility and viability were standardised after 2 …


Insufficient Radiofrequency Ablation Promotes Angiogenesis Of Residual Hepatocellular Carcinoma Via Hif-1Α/Vegfa, Jian Kong, Jinge Kong, Bing Pan, Shan Ke, Shuying Dong, Xiuli Li, Aimin Zhou, Lemin Zheng, Wen Bing Sun May 2012

Insufficient Radiofrequency Ablation Promotes Angiogenesis Of Residual Hepatocellular Carcinoma Via Hif-1Α/Vegfa, Jian Kong, Jinge Kong, Bing Pan, Shan Ke, Shuying Dong, Xiuli Li, Aimin Zhou, Lemin Zheng, Wen Bing Sun

Chemistry Faculty Publications

Background: The mechanism of rapid growth of the residual tumor after radiofrequency (RF) ablation is poorly understood. In this study, we investigated the effect of hyperthermia on HepG2 cells and generated a subline with enhanced viability and dys-regulated angiogenesis in vivo, which was used as a model to further determine the molecular mechanism of the rapid growth of residual HCC after RF ablation. Methodology/Principal Findings: Heat treatment was used to establish sublines of HepG2 cells. A subline (HepG2 k) with a relatively higher viability and significant heat tolerance was selected. The cellular protein levels of VEGFA, HIF-1α and p-Akt, VEGFA …


Introducing Nob-Nobs: Nitrogen-Oxygen-Boron Cycles With Potential High-Energy Properties, Aloysus K. Lawong, David W. Ball May 2012

Introducing Nob-Nobs: Nitrogen-Oxygen-Boron Cycles With Potential High-Energy Properties, Aloysus K. Lawong, David W. Ball

Chemistry Faculty Publications

As a follow-up on a study of a family of boron-oxygen-nitrogen compounds composed of two datively bonded B–O–N backbones, we investigate a similar series of compounds that have similar fragments but are covalently bonded. B3LYP/6-31G(d,p) quantum mechanical calculations have been performed to determine the minimum-energy geometries, vibrational frequencies, and thermochemical properties of the parent compound and a series of nitro-substituted derivatives. Our results indicate that some of the derivatives have at least appropriate thermodynamics for possible high-energy materials, in some cases being favorable over similar dimeric compounds with coordinate covalent B–N bonds


Bon-Bons: Cyclic Molecules With A Boron-Oxygen-Nitrogen Backbone. Computational Studies Of Their Thermodynamic Properties, Aloysus K. Lawong, David W. Ball Apr 2012

Bon-Bons: Cyclic Molecules With A Boron-Oxygen-Nitrogen Backbone. Computational Studies Of Their Thermodynamic Properties, Aloysus K. Lawong, David W. Ball

Chemistry Faculty Publications

Although they were first reported in 1963, molecules with a boron-oxygen-nitrogen dimeric backbone do not seem to have been investigated seriously in terms of thermodynamic properties. Here we report on the calculated structures and properties, including thermodynamics, of several so-called “BON-BON” molecules. With the popularity of nitrogen-containing substituents on new high-energy materials, nitro-substituted BON-BONs were a focus of our investigation. A total of 42 BON-BON molecules were evaluated, and thermochemical analysis shows a decrease in the specific enthalpy of combustion or decomposition with increasing NO2 content, consistent with other systems.


Probe Functionalization With A Rhop-3 Antibody: Toward A Rhop-3 Antigen Immunosensor For Detection Of Malaria, Salaam Saleh, Susan Moreno Molek, Perera N. Indika, Alan Riga, Tobili Sam Yellowe, Mekki Bayachou Mar 2012

Probe Functionalization With A Rhop-3 Antibody: Toward A Rhop-3 Antigen Immunosensor For Detection Of Malaria, Salaam Saleh, Susan Moreno Molek, Perera N. Indika, Alan Riga, Tobili Sam Yellowe, Mekki Bayachou

Chemistry Faculty Publications

The antibody specific for the malaria protein, Rhop-3, and FL-Rhop-3, were immobilized on the surface of a gold electrode modified with cysteamine. Colloidal gold was used to enhance the detection signal for Rhop-3 antigens. The Rhop-3 antibody was also immobilized on gold electrodes preactivated with dithiobis(succinimidyl proprionate) (DSP). Immobilization was performed at room temperature and at 37 °C. Cyclic voltammetry (CV) was used to monitor the interaction between the immobilized antibody and its cognate antigen in solution, using ferricyanide, K3Fe(CN)6, as reporting electroactive probe. Tests indicate recognition of Rhop-3 protein by the immobilized antibody. Antigen recognition was enhanced by incubation …


Development Of A ‘Clickable’ Non-Natural Nucleotide To Visualize The Replication Of Non-Instructional Dna Lesions, Edward A. Motea, Irene Lee, Anthony J. Berdis Jan 2012

Development Of A ‘Clickable’ Non-Natural Nucleotide To Visualize The Replication Of Non-Instructional Dna Lesions, Edward A. Motea, Irene Lee, Anthony J. Berdis

Chemistry Faculty Publications

The misreplication of damaged DNA is an important biological process that produces numerous adverse effects on human health. This report describes the synthesis and characterization of a non-natural nucleotide, designated 3-ethynyl-5-nitroindolyl-2′-deoxyriboside triphosphate (3-Eth-5-NITP), as a novel chemical reagent that can probe and quantify the misreplication of damaged DNA. We demonstrate that this non-natural nucleotide is efficiently inserted opposite an abasic site, a commonly formed and potentially mutagenic non-instructional DNA lesion. The strategic placement of the ethynyl moiety allows the incorporated nucleoside triphosphate to be selectively tagged with an azide-containing fluorophore using ‘click’ chemistry. This reaction provides a facile way to …


From Cox-2 Inhibitor Nimesulide To Potent Anti-Cancer Agent: Synthesis, In Vitro, In Vivo And Pharmacokinetic Evaluation, Bo Zhong, Xiaohan Cai, Snigdha Chennamaneni, Xin Yi, Lili Liu, John J. Pink, Afshin Dowlati, Yan Xu, Aimin Zhou, Bin Su Jan 2012

From Cox-2 Inhibitor Nimesulide To Potent Anti-Cancer Agent: Synthesis, In Vitro, In Vivo And Pharmacokinetic Evaluation, Bo Zhong, Xiaohan Cai, Snigdha Chennamaneni, Xin Yi, Lili Liu, John J. Pink, Afshin Dowlati, Yan Xu, Aimin Zhou, Bin Su

Chemistry Faculty Publications

Cyclooxygenase-2 (COX-2) inhibitor nimesulide inhibits the proliferation of various types of cancer cells mainly via COX-2 independent mechanisms, which makes it a good lead compound for anti-cancer drug development. In the presented study, a series of new nimesulide analogs were synthesized based on the structure–function analysis generated previously. Some of them displayed very potent anti-cancer activity with IC50s around 100 nM–200 nM to inhibit SKBR-3 breast cancer cell growth. CSUOH0901 (NSC751382) from the compound library also inhibits the growth of the 60 cancer cell lines used at National Cancer Institute Developmental therapeutics Program (NCIDTP) with IC50s around 100 nM–500 nM. …


Removal Of Uracil By Uracil Dna Glycosylase Limits Pemetrexed Cytotoxicity: Overriding The Limit With Methoxyamine To Inhibit Base Excision Repair, A. D. Bulgar, L. D. Weeks, Y. Miao, S. Yang, Yan Xu, C. Guo, S. Markowitz, N. Oleinick, S. L. Gerson, Lili Liu Jan 2012

Removal Of Uracil By Uracil Dna Glycosylase Limits Pemetrexed Cytotoxicity: Overriding The Limit With Methoxyamine To Inhibit Base Excision Repair, A. D. Bulgar, L. D. Weeks, Y. Miao, S. Yang, Yan Xu, C. Guo, S. Markowitz, N. Oleinick, S. L. Gerson, Lili Liu

Chemistry Faculty Publications

Uracil DNA glycosylase (UDG) specifically removes uracil bases from DNA, and its repair activity determines the sensitivity of the cell to anticancer agents that are capable of introducing uracil into DNA. In the present study, the participation of UDG in the response to pemetrexed-induced incorporation of uracil into DNA was studied using isogenic human tumor cell lines with or without UDG (UDG+/+/UDG−/−). UDG−/− cells were very sensitive to pemetrexed. Cell killing by pemetrexed was associated with genomic uracil accumulation, stalled DNA replication, and catastrophic DNA strand breaks. By contrast, UDG+/+ cells were >10 times more resistant to pemetrexed due to …


Nitric Oxide Synthase Encapsulation In Liposomes: A Potential Delivery Platform To (Nitric Oxide)-Deficient Targets, Reshani H. Perera, Pubudu M. Peiris, Serban F. Peteu, Mekki Bayachou Jan 2012

Nitric Oxide Synthase Encapsulation In Liposomes: A Potential Delivery Platform To (Nitric Oxide)-Deficient Targets, Reshani H. Perera, Pubudu M. Peiris, Serban F. Peteu, Mekki Bayachou

Chemistry Faculty Publications

Nitric oxide (NO) is a freely diffusible, gaseous free radical, associated with many physiological and pathological processes: such as neuronal signaling, immune response and inflammatory response. In mammalian organisms, NO is produced from L-arginine in an NADPH-dependent reaction catalyzed by a family of nitric oxide synthase (NOS) enzymes. Typically, large NO fluctuations in biological systems under/over a critical limit is associated with problems that range from transient dysfunctions to severe chronic disease states. In this regard, we explore the development of a potential delivery and release method of nitric oxide to NO-deficient sites using liposomes as vehicles. Liposomes have already …


Maxwell's Equations, Part V, David W. Ball Jan 2012

Maxwell's Equations, Part V, David W. Ball

Chemistry Faculty Publications

This is the fifth installment in a series devoted to explaining Maxwell’s equations, the four mathematical statements upon which the classical theory of electromagnetic fields – and light – is based. Previous installments can be found on Spectroscopy’s website (whose URL can be found throughout these issues). Maxwell’s equations are expressed in the language of vector calculus, so a significant part of some previous columns have been devoted to explaining vector calculus, not spectroscopy. For better or worse, that’s par for the course, and it’s my job to explain it well – I trust readers will let me know if …