Chemistry Commons^™

Synthesis And Evaluation Of Protein-Phenylboronic Acid Conjugates As Lectin Mimetics, Joshua Whited, Czharena Kay Rama, Xue-Long Sun

Chemistry Faculty Publications

Glycan-binding molecules, such as lectins, are very important tools for characterizing, imaging, or targeting glycans and are often involved in either physiological or pathological processes. However, their availability is far less compared to the diversity of native glycans. Therefore, development of lectin mimetics with desired specificity and affinity is in high demand. Boronic acid reacts with 1,2- and 1,3-diols of saccharides in aqueous media through reversible boronate ester formation and are regarded as synthetic lectin mimetics. In this study, bovine serum albumin (BSA)-phenylboronic acid (PBA) conjugates were synthesized in a density-controlled manner by targeting both aspartic and glutamic acids to …

Manganese Oxide/Hemin-Functionalized Graphene As A Platform For Peroxynitrite Sensing, Haitham F. Kalil, Shaimaa Maher, Tiyash Bose, Mekki Bayachou

Chemistry Faculty Publications

Peroxynitrite (ONOO−, PON) is a powerful oxidizing agent generated in vivo by the diffusion-limited reaction of nitric oxide (NO) and superoxide (O₂˙⁻) radicals. Under oxidative stress, cumulated peroxynitrite levels are associated with chronic inflammatory disorders and other pathophysiological conditions. The accurate detection of peroxynitrite in biological systems is important, not only to understand the genesis and development of diseases, but also to explore and design potential therapeutics. Herein, a manganese oxide/hemin-modified graphene interface is explored as a platform for peroxynitrite amperometric detection. Hemin-functionalized reduced graphene oxide was further modified with manganese oxide nanoparticles to provide a …

N-Glycosylation In The Protease Domain Of Trypsin-Like Serine Proteases Mediates Calnexin-Assisted Protein Folding, Hao Wang, Shuo Li, Juejin Wang, Shenghan Chen, Xue-Long Sun, Qingyu Wu

Chemistry Faculty Publications

Trypsin-like serine proteases are essential in physiological processes. Studies have shown that N-glycans are important for serine protease expression and secretion, but the underlying mechanisms are poorly understood. Here, we report a common mechanism of N-glycosylation in the protease domains of corin, enteropeptidase and prothrombin in calnexin-mediated glycoprotein folding and extracellular expression. This mechanism, which is independent of calreticulin and operates in a domain-autonomous manner, involves two steps: direct calnexin binding to target proteins and subsequent calnexin binding to monoglucosylated N-glycans. Elimination of N-glycosylation sites in the protease domains of corin, enteropeptidase and prothrombin inhibits corin and enteropeptidase cell surface …

A Galactomannoglucan Derived From Agaricus Brasiliensis: Purification, Characterization And Macrophage Activation Via Mapk And Ikappab/Nfkappab Pathways, Yanqing Zhang, Danting Liu, Leilei Fang, Xiaotong Zhao, Aimin Zhou, Junbo Xie

Chemistry Faculty Publications

In this study, a novel galactomannoglucan named as TJ2 was isolated from Agaricus brasiliensis with microwave extraction, macroporous resin, ion exchange resin and high resolution gel chromatography. TJ2 is composed of glucose, mannose and galactose in the ratio 99.2:0.2:0.6. Infrared spectra (IR), methylation analysis and nuclear magnetic resonance spectra indicated that TJ2 mainly contained a b-(1?3) – linked glucopyranosyl backbone. Interestingly, TJ2 significantly promoted RAW264.7 cell proliferation, and was able to activate the cells to engulf E. coli. In addition, TJ2 induced the expression of Interleukin 1b (IL-1b), Interleukin 6 (IL-6), tumor necrosis factor a (TNF-a) and cyclooxygenase-2 (Cox-2) in …

Endothelial Nitric Oxide Synthase Oxygenase On Lipid Nanodiscs: A Nano-Assembly Reflecting Native-Like Function Of Enos, Ghaith Altawallbeh, Mohammad M. Haque, Kiril A. Streletzky, Dennis J. Stuehr, Mekki Bayachou

Physics Faculty Publications

© 2017 Elsevier Inc. Endothelial nitric oxide synthase (eNOS) is a membrane-anchored enzyme. To highlight the potential role and effect of membrane phospholipids on the structure and activity of eNOS, we have incorporated the recombinant oxygenase subunit of eNOS into lipid nanodiscs. Two different size distribution modes were detected by multi-angle dynamic light scattering both for empty nanodiscs, and nanodiscs-bound eNOSoxy. The calculated hydrodynamic diameter for mode 1 species was 9.0 nm for empty nanodiscs and 9.8 nm for nanodisc bound eNOSoxy. Spectroscopic Griess assay was used to measure the enzymatic activity. Remarkably, the specific activity of nanodisc-bound eNOSoxy is …

The Future Perspective: Metabolomics In Laboratory Medicine For Inborn Errors Of Metabolism, Yana Sandlers

Chemistry Faculty Publications

Metabolomics can be described as a simultaneous and comprehensive analysis of small molecules in a biological sample. Recent technological and bioinformatics advances have facilitated large-scale metabolomic studies in many areas, including inborn errors of metabolism (IEMs). Despite significant improvements in the diagnosis and treatment of some IEMs, it is still challenging to understand how genetic variation affects disease progression and susceptibility. In addition, a search for new more personalized therapies and a growing demand for tools to monitor the long-term metabolic effects of existing therapies set the stage for metabolomics integration in preclinical and clinical studies. While targeted metabolomics approach …

Spellbinding Effects Of The Acidic Cooh-Terminus Of Factor Va Heavy Chain On Prothrombinase Activity And Function, Jamila Hirbawi, Michael Kalafatis

Chemistry Faculty Publications

Human factor Va (hfVa) is the important regulatory subunit of prothrombinase. Recent modeling data have suggested a critical role for amino acid Arg of hfVa for human prothrombin (hPro) activation by prothrombinase. Furthermore, it has also been demonstrated that hfVa has a different effect than that of bovine fVa on prethrombin-1 activation by prothrombinase. The difference between the two cofactor molecules was also found within the Asn-Arg dipeptide in the human factor V (hfV) molecule, which is replaced by the Asp-Glu sequence in bfV. As a consequence, we produced a recombinant hfV (rhfV) molecule with the substitution NR→DE. rhfV together …

Development And Validation Of A Novel Lc–Ms/Ms Method For Simultaneous Determination Of Abiraterone And Its Seven Steroidal Metabolites In Human Serum: Innovation In Separation Of Diastereoisomers Without Use Of A Chiral Column, Mohammad Alyamani, Zhenfei Li, Sunil K. Upadhyay, David J. Anderson, Richard J. Auchus, Nima Sharifi

Chemistry Faculty Publications

Abiraterone acetate (AA), the prodrug of abiraterone, is FDA-approved for the treatment of castration-resistant prostate cancer. Abiraterone is metabolized in patients to a more potent analogue, D4A. However, we have recently reported that this analogue is further metabolized to additional metabolites in patients treated with AA. Here, we present a liquid chromatography-tandem mass spectrometry method developed to resolve and detect abiraterone and its seven metabolites in human serum using an AB Sciex Qtrap 5500 mass analyzer coupled with a Shimadzu Nexera UPLC station. Analytes and the internal standard (abiraterone-d4) were extracted from human serum using the liquid–liquid extraction procedure. The …

Inhibiting Translesion Dna Synthesis As An Approach To Combat Drug Resistance To Dna Damaging Agents, Jung-Suk Choi, Seol Kim, Edward Motea, Anthony J. Berdis

Chemistry Faculty Publications

Anti-cancer agents exert therapeutic effects by damaging DNA. Unfortunately, DNA polymerases can effectively replicate the formed DNA lesions to cause drug resistance and create more aggressive cancers. To understand this process at the cellular level, we developed an artificial nucleoside that visualizes the replication of damaged DNA to identify cells that acquire drug resistance through this mechanism. Visualization is achieved using "click" chemistry to covalently attach azide-containing fluorophores to the ethynyl group present on the nucleoside analog after its incorporation opposite damaged DNA. Flow cytometry and microscopy techniques demonstrate that the extent of nucleotide incorporation into genomic DNA is enhanced …

Copalic Acid Analogs Down-Regulate Androgen Receptor And Inhibit Small Chaperone Protein, Nethrie D. Idippily, Qiaoyun Zheng, Chunfang Gan, Aicha Quamine, Morgan M. Ashcraft, Bo Zhong, Bin Su Ph.D.

Chemistry Faculty Publications

Copalic acid, one of the diterpenoid acids in copaiba oil, inhibited the chaperone function of α-crystallin and heat shock protein 27 kD (HSP27). It also showed potent activity in decreasing an HSP27 client protein, androgen receptor (AR), which makes it useful in prostate cancer treatment or prevention. To develop potent drug candidates to decrease the AR level in prostate cancer cells, more copalic acid analogs were synthesized. Using the level of AR as the readout, 15 of the copalic acid analogs were screened and two compounds were much more potent than copalic acid. The compounds also dose-dependently inhibited AR positive …

Hmba Is A Putative Hsp70 Activator Stimulating Hexim1 Expression That Is Down-Regulated By Estrogen, Rati Lama, Chunfang Gan, Nethrie Idippily, Viharika Bobba, David Danielpour, Monica Montano, Bin Su Ph.D.

Chemistry Faculty Publications

Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is identified as a novel inhibitor of estrogen stimulated breast cell growth, and it suppresses estrogen receptor-a transcriptional activity. HEXIM1 protein level has been found to be downregulated by estrogens. Recently, HEXIM1 has been found to inhibit androgen receptor transcriptional activity as well. Researchers have used Hexamethylene bisacetamide (HMBA) for decades to stimulate HEXIM1 expression, which also inhibit estrogen stimulated breast cancer cell gene activation and androgen stimulated prostate cancer gene activation. However, the direct molecular targets of HMBA that modulate the induction of HEXIM1 expression in mammalian cells have not been identified. Based …

A Dilute-And-Shoot Flow-Injection Tandem Mass Spectrometry Method For Quantification Of Phenobarbital In Urine, Ravali Alagandula, Xiang Zhou, Baochuan Guo

Chemistry Faculty Publications

RATIONALE: Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized.

METHODS: This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample …

Synthetic Melanin Films As Potential Interfaces For Peroxynitrite Detection And Quantification, Haitham F. Kalil, Shaimaa Mahera, Tiyash Bosed, Ousama Al-Mahmoude, Clara Kay, Mekki Bayachou

Chemistry Faculty Publications

Peroxynitrite (PON) is a highly reactive oxygen-nitrogen species that facilitates both oxidation and nitration reactions. Early reports have revealed the deleterious effects of PON on DNA, proteins, and lipids. Recent studies have suggested that melanin can act as an antioxidative therapy to scavenge the reactive oxygen-nitrogen species (RO-NS) including PON. Melanin is a natural pigment that has many physiological functions involving the neutralization of highly oxidative species. In this project, the interaction between PON and synthetic melanin has been studied. In addition, the electrochemical characteristics of the polymerized 5,6-dihydroxy indole (DHI) as a model of synthetic melanin were examined using …

Weikangning Therapy In Functional Dyspepsia And The Protective Role Of Nrf2, Yujuan Chang, Wei Wei, Li Tong, Yanjun Liu, Aimin Zhou, Jiande Chen, Ruhan Wei, Ping Zhang, Xiaolan Su

Chemistry Faculty Publications

Functional dyspepsia (FD) is a non-organic gastro-intestinal disorder that has a marked negative impact on quality of life. Compared with conventional pharmacological therapies, the traditional Chinese medicine weikangning (WKN) is a safe and effective treatment for FD. The present study aimed to determine the molecular mechanisms underlying the efficacy of WKN. The effect of different concentrations of WKN on the proliferation of the human gastric mucosal epithelial cell line GES-1 was assessed. The optimal WKN concentration to promote cell proliferation was determined, and this concentration was used to examine the effect of WKN compared with a domperidone-treated positive control group …

Myeloperoxidase-Mediated Protein Lysine Oxidation Generates 2- Aminoadipic Acid And Lysine Nitrile In Vivo, Hongqiao Lin, Bruce S. Levison, Jennifer A. Buffa, Ying Huang, Xiaoming Fu, Zeneng Wang, Valentin Gogonea, Joseph A. Didonato, Stanley L. Hazen

Chemistry Faculty Publications

Recent studies reveal 2-aminoadipic acid (2-AAA) is both elevated in subjects at risk for diabetes and mechanistically linked to glucose homeostasis. Prior studies also suggest enrichment of protein-bound 2-AAA as an oxidative post-translational modification of lysyl residues in tissues associated with degenerative diseases of aging. While in vitro studies suggest redox active transition metals or myeloperoxidase (MPO) generated hypochlorous acid (HOCl) may produce protein-bound 2-AAA, the mechanism(s) responsible for generation of 2- AAA during inflammatory diseases are unknown. In initial studies we observed that traditional acid- or basecatalyzed protein hydrolysis methods previously employed to measure tissue 2-AAA can artificially generate …

Synthesis Of Vorinostat And Cholesterol Conjugate To Enhance The Cancer Cell Uptake Selectivity, Nethrie D. Idippily, Chunfang Gan, Paul Orefice, Jane Peterson, Bin Su Ph.D.

Chemistry Faculty Publications

Histone deacetylase (HDAC) inhibitors modulate various cellular functions including proliferation, differentiation, and apoptosis. Vorinostat (SuberAniloHydroxamic Acid, SAHA) is the first HDAC inhibitor approved by FDA for cancer treatment. However, SAHA distributes in cancer tissue and normal tissue in similar levels. It will be ideal to selectively deliver SAHA into cancer cells. Rapidly growing cancer cells have a great need of cholesterol. Low-density lipoprotein (LDL) is the major cholesterol carrier in plasma and its uptake is mediated by LDL-receptor (LDL-R), a glycoprotein overexpressed on the surface of cancer cells. Herein, we designed and synthesized a SAHA cholesterol conjugate, and further formed …

Glutathione Species And Metabolomic Prints In Subjects With Liver Disease As Biological Markers For The Detection Of Hepatocellular Carcinoma, Juan R. Sanabria, Rajan S. Kombu, Guo Fang Zhang, Yana Sandlers, Jizhou Ai, Rafael A. Ibarra, Rime Abbas, Kush Goyal, Henri Brunengraber

Chemistry Faculty Publications

© 2016 The Authors Background The incidence of liver disease is increasing in USA. Animal models had shown glutathione species in plasma reflects liver glutathione state and it could be a surrogate for the detection of hepatocellular carcinoma (HCC). Methods The present study aimed to translate methods to the human and to explore the role of glutathione/metabolic prints in the progression of liver dysfunction and in the detection of HCC. Treated plasma from healthy subjects (n = 20), patients with liver disease (ESLD, n = 99) and patients after transplantation (LTx, n = 7) were analyzed by GC- or LC/MS. …

Oncogenic Pik3ca Mutations Reprogram Glutamine Metabolism In Colorectal Cancer, Yujun Hao, Yardena Samuels, Qingling Li, Dawid Krokowski, Bo-Jhih Guan, Chao Wang, Zhicheng Jin, Bohan Dong, Bo Cao, Xiujing Feng, Min Xiang, Claire Xu, Stephen Fink, Neal J. Meropol, Yan Xu

Chemistry Faculty Publications

Cancer cells often require glutamine for growth, thereby distinguishing them from most normal cells. Here we show that PIK3CA mutations reprogram glutamine metabolism by upregulating glutamate pyruvate transaminase 2 (GPT2) in colorectal cancer (CRC) cells, making them more dependent on glutamine. Compared with isogenic wild-type (WT) cells, PIK3CA mutant CRCs convert substantially more glutamine to alpha-ketoglutarate to replenish the tricarboxylic acid cycle and generate ATP. Mutant p110 alpha upregulates GPT2 gene expression through an AKT-independent, PDK1-RSK2-ATF4 signalling axis. Moreover, aminooxyacetate, which inhibits the enzymatic activity of aminotransferases including GPT2, suppresses xenograft tumour growth of CRCs with PIK3CA mutations, but not …

Novel Protein Disulfide Isomerase Inhibitor With Anticancer Activity In Multiple Myeloma, Sergei Vatolin, James G. Phillips, Babal K. Jha, Shravya Govindgari, Jennifer Hu, Dale Grabowski, Yvonne Parker, Daniel J. Lindner, Fei Zhong, Clark W. Distelhorst, Mitchell R. Smith, Claudiu Cotta, Yan Xu, Sujatha Chilakala, Rebecca R. Kuang, Samantha Tall, Frederic J. Reu

Chemistry Faculty Publications

Multiple myeloma cells secrete more disulfide bond–rich proteins than any other mammalian cell. Thus, inhibition of protein disulfide isomerases (PDI) required for protein folding in the endoplasmic reticulum (ER) should increase ER stress beyond repair in this incurable cancer. Here, we report the mechanistically unbiased discovery of a novel PDI-inhibiting compound with antimyeloma activity. We screened a 30,355 small-molecule library using a multilayered multiple myeloma cell–based cytotoxicity assay that modeled disease niche, normal liver, kidney, and bone marrow. CCF642, a bone marrow–sparing compound, exhibited a submicromolar IC₅₀ in 10 of 10 multiple myeloma cell lines. An active biotinylated analog …

Early Growth And Development Impairments In Patients With Ganglioside Gm3 Synthase Deficiency, H. Wang, A. Wang, Dan Wang, A. Bright, V. Sency, Aimin Zhou, B. Xin

Chemistry Faculty Publications

Ganglioside GM3 synthase is a key enzyme involved in the biosynthesis of gangliosides. GM3 synthase deficiency (GSD) causes a complete absence of GM3 and all downstream biosynthetic derivatives. The individuals affected by this disorder manifest severe irritability, intractable seizures and profound intellectual disability. However, we have found that most newborns seem symptom-free for a period of time after birth. In order to further understand the onset of the disease, we investigated the early growth and development of patients with this condition through this study. We compared 37 affected individuals with their normal siblings and revealed that all children with GSD …

Metabolomics Reveals New Mechanisms For Pathogenesis In Barth Syndrome And Introduces Novel Roles For Cardiolipin In Cellular Function, Yana Sandlers, Kelly Mercier, Wimal Pathmasiri, Jim Carlson, Susan Mcritchie, Susan Sumner, Hilary J. Vernon

Chemistry Faculty Publications

Barth Syndrome is the only known Mendelian disorder of cardiolipin remodeling, with characteristic clinical features of cardiomyopathy, skeletal myopathy, and neutropenia. While the primary biochemical defects of reduced mature cardiolipin and increased monolysocardiolipin are well-described, much of the downstream biochemical dysregulation has not been uncovered, and biomarkers are limited. In order to further expand upon the knowledge of the biochemical abnormalities in Barth Syndrome, we analyzed metabolite profiles in plasma from a cohort of individuals with Barth Syndrome compared to age-matched controls via ¹H nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry. A clear distinction between metabolite profiles of …

A Systematic Investigation Of Structure/Function Requirements For The Apolipoprotein A-I/Lecithin Cholesterol Acyltransferase Interaction Loop Of High-Density Lipoprotein, Xiaodong Gu, Zhiping Wu, Ying Huang, Matthew A. Wagner, Camelia Baleanu Gogonea, Ryan A. Mehl, Jennifer A. Buffa, Anthony J. Didonato, Leah B. Hazen, Paul L. Fox, Valentin Gogonea, John S. Parks, Joseph A. Didonato, Stanley L. Hazen

Chemistry Faculty Publications

The interaction of lecithin-cholesterol acyltransferase (LCAT) with apolipoprotein A-I (apoA-I) plays a critical role in high-density lipoprotein (HDL) maturation. We previously identified a highly solvent-exposed apoA-I loop domain (Leu159–Leu170) in nascent HDL, the so-called “solar flare” (SF) region, and proposed that it serves as an LCAT docking site (Wu, Z., Wagner, M. A., Zheng, L., Parks, J. S., Shy, J. M., 3rd, Smith, J. D., Gogonea, V., and Hazen, S. L. (2007) Nat. Struct. Mol. Biol. 14, 861–868). The stability and role of the SF domain of apoA-I in supporting HDL binding and activation of LCAT are debated. Here we …

The Dual Regulatory Role Of Amino Acids Leu480 And Gln481 Of Prothrombin, Joesph R. Wiencek, Jamila Hirbawi, Vivien C. Yee, Michael Kalafatis

Chemistry Faculty Publications

Prothrombin (FII) is activated to α-thrombin (IIa) by prothrombinase. Prothrombinase is composed of a catalytic subunit, factor Xa (fXa), and a regulatory subunit, factor Va (fVa), assembled on a membrane surface in the presence of divalent metal ions. We constructed, expressed, and purified several mutated recombinant FII (rFII) molecules within the previously determined fVa-dependent binding site for fXa (amino acid region 473–487 of FII). rFII molecules bearing overlapping deletions within this significant region first established the minimal stretch of amino acids required for the fVa-dependent recognition exosite for fXa in prothrombinase within the amino acid sequence Ser⁴⁷⁸–Val^{479 …}

Identification Of Critical Paraoxonase 1 Residues Involved In High Density Lipoprotein Interaction, Xiaodong Gu, Ying Huang, Bruce S. Levison, Gary Gerstenecker, Anthony J. Didonato, Leah B. Hazen, Joonsue Lee, Valentin Gogonea, Joseph A. Didonato, Stanley L. Hazen

Chemistry Faculty Publications

Paraoxonase 1 (PON1) is a high density lipoprotein (HDL)-associated protein with atherosclerosis-protective and systemic anti-oxidant functions. We recently showed that PON1, myeloperoxidase, and HDL bind to one another in vivo forming a functional ternary complex (Huang, Y., Wu, Z., Riwanto, M., Gao, S., Levison, B. S., Gu, X., Fu, X., Wagner, M. A., Besler, C., Gerstenecker, G., Zhang, R., Li, X. M., Didonato, A. J., Gogonea, V., Tang, W. H., et al. (2013) J. Clin. Invest. 123, 3815–3828). However, specific residues on PON1 involved in the HDL-PON1 interaction remain unclear. Unambiguous identification of protein residues involved in docking interactions to …

Orally Active And Selective Tubulin Inhibitors As Anti-Trypanosome Agents, Vishal Nanavaty, Rati Lama, Ranjodh Sandhu, Bo Zhong, Daniel Kulman, Viharika Bobba, Anran Zhao, Bibo Li, Bin Su

Chemistry Faculty Publications

Objectives: There is an urgent need to develop a safe, effective, orally active, and inexpensive therapy for African trypanosomiasis due to the drawbacks of current drugs. Selective tubulin inhibitors have the potential to be promising drug candidates for the treatment of this disease, which is based on the tubulin protein structural difference between mammalian and trypanosome cells. We propose to identify novel tubulin inhibitors from a compound library developed based on the lead compounds that selectively target trypanosomiasis. Methods: We used Trypanosoma brucei brucei as the parasite model, and human normal kidney cells and mouse microphage cells as the host …

Structural Insights Into High Density Lipoprotein: Old Models And New Facts, Valentin Gogonea

Chemistry Faculty Publications

The physiological link between circulating high density lipoprotein (HDL) levels and cardiovascular disease is well-documented, albeit its intricacies are not well-understood. An improved appreciation of HDL function and overall role in vascular health and disease requires at its foundation a better understanding of the lipoprotein's molecular structure, its formation, and its process of maturation through interactions with various plasma enzymes and cell receptors that intervene along the pathway of reverse cholesterol transport. This review focuses on summarizing recent developments in the field of lipid free apoA-I and HDL structure, with emphasis on new insights revealed by newly published nascent and …

Tmco1 Is An Er Ca2+ Load-Activated Ca2+ Channel, Qiao-Chu Wang, Qiaoxia Zheng, Haiyan Tan, Bing Zhang, Xiaoling Li, Yuxiu Yang, Jie Yu, Yang Liu, Hao Chai, Xi Wang, Zhongshuai Sun, Jiu-Qiang Wang, Shu Zhu, Fengli Wang, Maojun Yang, Caixia Guo, Heng Wang, Qingyin Zheng, Yang Li, Quan Chen, Aimin Zhou, Tie-Shan Tang

Chemistry Faculty Publications

Maintaining homeostasis of Ca2+stores in theendoplasmic reticulum (ER) is crucial for properCa2+signaling and key cellular functions. The Ca2+-release-activated Ca2+(CRAC) channel is respon-sible for Ca2+influx and refilling after store depletion,but how cells cope with excess Ca2+when ER storesare overloaded is unclear. We show that TMCO1 is anER transmembrane protein that actively preventsCa2+stores from overfilling, acting as what we terma ‘‘Ca2+load-activated Ca2+channel’’ or ‘‘CLAC’’channel. TMCO1 undergoes reversible homotetra-merization in response to ER Ca2+overloadingand disassembly upon Ca2+depletion and forms aCa2+-selective ion channel on giant liposomes.TMCO1 knockout mice reproduce the main clinicalfeatures of human cerebrofaciothoracic (CFT)dysplasia spectrum, a developmental disorder linkedto TMCO1 dysfunction, and …

Determination Of Mln0128, An Investigational Antineoplastic Agent, In Human Plasma By Lc–Ms/Ms, Sandeep R. Kunati, Yan Xu

Chemistry Faculty Publications

MLN0128, an mTOR kinase inhibitor, is currently undergoing clinical investigation for treatment of a variety of cancers. To support this work, an LC–MS/MS method has been developed for the determination of MLN0128 in human plasma. A structural analog STK040263 was used as the internal standard. Both MLN0128 and the IS were first extracted from plasma using methyl tert-butyl ether; then separated on a Waters XTerra® MS C18 column using a mobile phase consisting of methanol–acetonitrile–10.0 mm ammonium formate (34:6:60, v/v/v) at a flow rate of 0.300 mL min−1. Quantitation of MLN0128 was done by positive electrospray ionization tandem mass spectrometry …

Targeting Radioresistant Breast Cancer Cells By Single Agent Chk1 Inhibitor Via Enhancing Replication Stress, Yao Zhang, Jinzhi Lai, Zhanwen Du, Jinnan Gao, Shuming Yang, Shashank Gorityala, Xiahui Xiong, Ou Deng, Zhefu Ma, Chunhong Yan, Gonzalo Susana, Yan Xu, Junran Zhang

Chemistry Faculty Publications

Radiotherapy (RT) remains a standard therapeutic modality for breast cancer patients. However, intrinsic or acquired resistance limits the efficacy of RT. Here, we demonstrate that CHK1 inhibitor AZD7762 alone significantly inhibited the growth of radioresistant breast cancer cells (RBCC). Given the critical role of ATR/CHK1 signaling in suppressing oncogene-induced replication stress (RS), we hypothesize that CHK1 inhibition leads to the specific killing for RBCC due to its abrogation in the suppression of RS induced by oncogenes. In agreement, the expression of oncogenes c-Myc/CDC25A/c-Src/H-ras/E2F1 and DNA damage response (DDR) proteins ATR/CHK1/BRCA1/CtIP were elevated in RBCC. AZD7762 exposure led to significantly higher …

Sialyltransferase Inhibition And Recent Advances, Libo Wang, Ying Liu, Lijun Wu, Xue-Long Sun

Chemistry Faculty Publications

Sialic acids, existing as terminal sugars of glycoconjugates, play important roles in various physiological and pathological processes, such as cell–cell adhesion, immune defense, tumor cell metastasis, and inflammation. Sialyltransferases (STs) catalyze the transfer of sialic acid residues to non-reducing oligosaccharide chains of proteins and lipids, using cytidine monophosphate N-acetylneuraminic acid (CMP-Neu5Ac) as the donor. Elevated sialyltransferase activity leads to overexpression of cell surface sialic acids and contributes to many disease developments, such as cancer and inflammation. Therefore, sialyltransferases are considered as potential drug targets for disease treatment. Inhibitors of sialyltransferases thus are of medicinal interest, especially for the cancer …