Chemicals and Drugs Commons^™

Random Mutagenesis Of The Aspergillus Oryzae Genome Results In Fungal Antibacterial Activity, Cory A. Leonard, Stacy D. Brown, James Russell Hayman

ETSU Faculty Works

Multidrug-resistant bacteria cause severe infections in hospitals and communities. Development of new drugs to combat resistant microorganisms is needed. Natural products of microbial origin are the source of most currently available antibiotics. We hypothesized that random mutagenesis of Aspergillus oryzae would result in secretion of antibacterial compounds. To address this hypothesis, we developed a screen to identify individual A. oryzae mutants that inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA) in vitro. To randomly generate A. oryzae mutant strains, spores were treated with ethyl methanesulfonate (EMS). Over 3000 EMS-treated A. oryzae cultures were tested in the screen, and one isolate, …

Tigecycline Induction Of Phenol-Soluble Modulins By Invasive Methicillin-Resistant Staphylococcus Aureus Strains, Jason Yamaki, Timothy Synold, Annie Wong-Beringer

Pharmacy Faculty Articles and Research

We examined the effects of tigecycline on three types of exoproteins, α-type phenol-soluble modulins (PSMα1 to PSMα4), α-hemolysin, and protein A, in 13 methicillin-resistant Staphylococcus aureus isolates compared to those of clindamycin and linezolid. Paradoxical increases in PSMαs occurred in 77% of the isolates with tigecycline at 1/4 and 1/8 MICs and clindamycin at 1/8 MIC compared to only 23% of the isolates with linezolid at 1/8 MIC. Induction was specific to PSMα₁ to PSMα₄, as protein A and α-hemolysin production was decreased under the same conditions by all of the antibiotics used.

Human Milk Cortisol Is Associated With Infant Temperament, Katherine R. Grey, Elyssia Poggi Davis, Curt A. Sandman, Laura M. Glynn

Psychology Faculty Articles and Research

The implications of the biologically active elements in milk for the mammalian infant are largely unknown. Animal models demonstrate that transmission of glucocorticoids through milk influences behavior and modifies brain development in offspring. The aim of this study was to determine the relation between human milk cortisol levels and temperament of the breastfed infant. Fifty-two mother and infant pairs participated when the infants were three-months old. Milk cortisol levels were assessed and each mother completed the Infant Behavior Questionnaire (IBQ), a widely used parent-report measure of infant temperament. Analyses revealed a positive association between milk cortisol and the negative affectivity …

Identification Of Cisplatin-Binding Proteins Using Agarose Conjugates Of Platinum Compounds, Takatoshi Karasawa, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger

Chemistry Faculty Publications and Presentations

Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin’s selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin’s chloride sites that had been aquated. We hypothesized that cisplatin’s toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides …

Dynamic Modeling Of Nonmedical Opioid Initiation: Epidemic And Access, Alexandra Nielsen, Teresa D. Schmidt, Dennis Mccarty, Wayne W. Wakeland

Systems Science Faculty Publications and Presentations

We report development of a systems level dynamic model of initiation and nonmedical use of pharmaceutical opioids in the US. The model calibrated to 1995-2005 National Survey of Drug Use and Health (NSDUH) data, predicts 2006-2011 data well. Preliminary findings indicate that interventions which reduce the perceived attractiveness of opioids for recreational use may be able to reduce initiation and nonmedical use most significantly, while supply restriction effected through drug take back days and prescribing changes may have more modest effects. We argue that system dynamics is an effective approach for evaluating potential interventions to this complex system where the …

Data On The Diversion, Nonmedical Use And Adverse Outcomes Associated With Pharmaceutical Opioids, Amanuel Zimam, Teresa D. Schmidt, Alexandra Nielsen, Wayne W. Wakeland

Systems Science Faculty Publications and Presentations

Background: Recent increases in the nonmedical use of pharmaceutical opioids and the adverse outcomes associated with them have stimulated a large amount of research and data collection on this public health problem. Systematic organization of the available data sources is needed to facilitate ongoing research, analysis, and evaluation.

Method: A list of keywords associated with diversion, nonmedical use, and adverse outcomes of pharmaceutical opioid use generated 94 peer-reviewed academic articles and a number of governmental and nongovernmental sources. All sources were in English, contained quantitative data, and were published between January 1995 and April 2012. A list of 20 topics …

Cyclic Peptides Containing Tryptophan And Arginine As Src Kinase Inhibitors, Amir Nasrolahi Shirazi, Rakesh Tiwari, Alex Brown, Dindyal Mandal, Gongqin Sun, Keykavous Parang

Pharmacy Faculty Articles and Research

A number of cyclic and linear peptides containing various combinations of amino acids were evaluated for their Src kinase inhibitory potency. Among all the peptides, cyclic decapeptide C[RW]5 containing alternative arginine (R) and tryptophan (W) residues was found to be the most potent Src kinase inhibitor. C[RW]5 showed higher inhibitory activity (IC50=2.8 μM) than C[KW]5, L(KW)5, C[RW]4, and C[RW]3 with IC50 values of 46.9, 69.1, 21.5, and 25.0 μM, respectively, as determined in a fluorescence intensity-based assay. Thus, the cyclic nature, the presence of arginine, ring size, and the number of amino acids in the structure of the peptide were …

"Mercy Tape" Unveiled: Provides Better Weight Estimates For Children, Bill Van Kirk

Our Story Continues

Susan Abdel-Rahman, Pharm.D, Clinical Pharmacology and Medical Toxicology, led the Children's Mercy research team that developed the Mercy TAPE, a new device to estimate the weight of pediatric patients ages two months to 16 years.

Accurate weight estimates in resource-restricted settings (lacking the means to weigh a child) are important because they are used to determine appropriate medication dosage, fluid volumes for resuscitation, breathing tube sizes, and more.

Label-Free Detection Of Low Protein Concentration In Solution Using A Novel Colorimetric Assay, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Dual pH and temperature sensitive microgel-based etalons were fabricated by sandwiching a “monolithic” microgel layer between two semitransparent, Au layers. The devices exhibit visual color and multipeak reflectance spectra, both of which primarily depend on the distance between the Au surfaces mediated by the microgel diameter. We found that a polycationic polyelectrolyte can penetrate through the Au overlayer to interact with negatively charged microgel confined between Au overlayers. In this submission we report that biotinylated polycationic polymer can penetrate through the Au overlayer of a poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based etalon and cause the microgel layer to collapse. The collapse …

Oral Contraceptives, Stephenie G. Fortier

Senior Honors Theses

Cyclic oral contraceptive and continuous oral contraceptives have many similarities yet a few distinct differences. One of the major differences between cyclic and continuous oral contraceptives is that cyclic oral contraceptive pills have twenty one active pills and seven inactive pills versus the new continuous oral contraceptive pills which have 28 active pills and no inactive pills. However, though cyclic and continuous oral contraceptives do have a few differences, both types of oral contraceptives affect a woman’s body in similar ways. When choosing between cyclic and continuous oral contraceptives, it is important for women to be informed about the advantages …

Synthesis And Biological Evaluation Of Novel Folic Acid Receptor-Targeted, Β-Cyclodextrin-Based Drug Complexes For Cancer Treatment, Juan-Juan Yin, Sonali Sharma, Stepan P. Shumyak, Zhi-Xin Wang, Zhi-Wei Zhou, Yangde Zhang, Peixuan Guo, Chen-Zhong Li, Jagat R. Kanwar, Tianxin Yang, Shyam S. Mohapatra, Wanqing Liu, Wei Duan, Jian-Cheng Wang, Qi Li, Xueji Zhang, Jun Tan, Lee Jia, Jun Liang, Ming Q. Wei, Xioatian Lee, Shu-Feng Zhou

Department of Biomedical Engineering Faculty Publications

Drug targeting is an active area of research and nano-scaled drug delivery systems hold tremendous potential for the treatment of neoplasms. In this study, a novel cyclodextrin (CD)-based nanoparticle drug delivery system has been assembled and characterized for the therapy of folate receptor-positive [FR(+)] cancer. Water-soluble folic acid (FA)-conjugated CD carriers (FACDs) were successfully synthesized and their structures were confirmed by 1D/2D nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and circular dichroism. Drug complexes of adamatane (Ada) and cytotoxic doxorubicin (Dox) with FACD were readily …

Diabetic Db/Db Mice Exhibit Central Nervous System And Peripheral Molecular Alterations As Seen In Neurological Disorders., A. Ernst, Ajaykumar Narayan Sharma, Khalid M. Elased, P. C. Guest, H. Rahmoune, S. Bahn

Pharmacology and Toxicology Faculty Publications

The db/db mouse is a widely used preclinical model in diabetes research. Recent studies have shown that these mice also display aspects of psychosis and depression-like behaviors as seen in some psychiatric disorders. Here, we have performed multiplex immunoassay and liquid chromatography mass spectrometry profiling of the plasma and brain samples from db/db and control mice to identify altered pathways, which could be related to these behavioral abnormalities. This is the first study to carry out profiling of the brain proteome in this model. Plasma from the db/db mice had increased levels of leptin and insulin, decreased levels of peptide …

Cinacalcet As Adjunctive Therapy For Hereditary 1,25-Dihydroxyvitamin D-Resistant Rickets., Tarak Srivastava, Uri S. Alon

Manuscripts, Articles, Book Chapters and Other Papers

Secondary hyperparathyroidism from inadequate calcium absorption in the gut, is the underlying pathophysiology for rachitic changes in hereditary vitamin D-resistant rickets (HVDRR). We describe a novel use of Cinacalcet to treat a child with HVDRR in whom conventional modes of therapy had to be discontinued. Cinacalcet therapy with high-dose oral calcium effectively normalized the metabolic abnormalities and bone condition. The relative ease of administration of the calcimimetic as a once- or twice-daily oral preparation, compared with traditional intravenous calcium administration, should encourage its move to the frontline of treatment of the disorder.

Effect Of Leaving Ligands Of Platinum(Ii) Diamine Complexes On Dna And Protein Residues, Ramya Kolli

Masters Theses & Specialist Projects

Platinum compounds are widely used drugs in cancer treatments. Although DNA is the biological target, reaction of platinum compounds with proteins is also potentially significant. Our objective is to study the effects of leaving ligands on the relative reactivity between 5'-GMP (guanosine 5' phosphate), a key DNA target, and N-Acetyl - L-Methionine (N-AcMet), a key protein target. We have used NMR spectroscopy to monitor reactions with N-AcMet and 5'-GMP added to a platinum complex to see which products are formed preferentially. Previous research showed that both a non-bulky complex such as [Pt(en)(D₂O)₂]²⁺ [en=ethylenediamine], and a …

Polypharmacy In Elderly: A Cautious Trail To Tread, Saniya Raghib Sabzwari, Waris Qidwai, Seema Bhanji

Department of Family Medicine

Polypharmacy has now increasingly come into focus as the recipient of healthcare in old age worldwide. In elderly it is associated with frequent adverse drug reactions (ADRs) and drug-drug interactions resulting in significant morbidity. Geriatrics is still an emerging specialty in South Asia, especially in Pakistan, where multiple reasons for polypharmacy exist. An extensive literature review of articles using key words like \'polypharmacy,\' \'elderly\' was conducted. The recently updated Beers Criteria of classification of inappropriate drugs in the elderly was reviewed in detail. Articles of relevance to polypharmacy and evaluation of guidelines for appropriate interventions to minimise inappropriate drug prescribing …

Rosiglitazone Treatment Of Type 2 Diabetic Db/Db Mice Attenuates Urinary Albumin And Angiotensin Converting Enzyme 2 Excretion, Harshita Chodavarapu, Nadja Grobe, Hari Krishna Somineni, Esam Said Busah Salem, Malav Navinchandra Madhu, Khalid M. Elased

Pharmacology and Toxicology Faculty Publications

Alterations within the renal renin angiotensin system play a pivotal role in the development and progression of cardiovascular and renal disease. Angiotensin converting enzyme 2 (ACE2) is highly expressed in renal tubules and has been shown to be renoprotective in diabetes. The protease, a disintegrin and metalloprotease (ADAM) 17, is involved in the ectodomain shedding of several transmembrane proteins including ACE2. Renal ACE2 and ADAM17 were significantly increased in db/db mice compared to controls. We investigated the effect of the insulin sensitizer, rosiglitazone, on albuminuria, renal ADAM17 protein expression and ACE2 shedding in db/db diabetic mice. …

Divergent Protein Motifs Direct Ef-P Mediated Translational Regulation In Salmonella And Escherichia Coli, Steven J. Hersch, Mengchi Wang, S. Betty Zou, Kyung-Mee Moon, Leonard J. Foster, Michael Ibba, William Wiley Navarre

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Elongation factor P (EF-P) is a universally conserved bacterial translation factor homologous to eukaryotic/archaeal initiation factor 5A. In Salmonella, deletion of the efp gene results in pleiotropic phenotypes, including increased susceptibility to numerous cellular stressors. Only a limited number of proteins are affected by the loss of EF-P, and it has recently been determined that EF-P plays a critical role in rescuing ribosomes stalled at PPP and PPG peptide sequences. Here we present an unbiased in vivo investigation of the specific targets of EF-P by employing stable isotope labeling of amino acids in cell culture (SILAC) to compare the …

Design, Synthesis And Evaluation Of Antimicrobial Activity Of N-Terminal Modified Leucocin A Analogues, Krishna Chaitanya Bodapati, Rania Soudy, Hashem Etayash, Michael Stiles, Kamaljit Kaur

Pharmacy Faculty Articles and Research

Class IIa bacteriocins are potent antimicrobial peptides produced by lactic acid bacteria to destroy competing microorganisms. The N-terminal domain of these peptides consists of a conserved YGNGV sequence and a disulphide bond. The YGNGV motif is essential for activity, whereas, the two cysteines involved in the disulphide bond can be replaced with hydrophobic residues. The C-terminal region has variable sequences, and folds into a conserved amphipathic α-helical structure. To elucidate the structure–activity relationship in the N-terminal domain of these peptides, three analogues (1–3) of a class IIa bacteriocin, Leucocin A (LeuA), were designed and synthesized by …

Testosterone, Cardiovascular, Men, Trial, Lin Xu, Guy Freeman, Benjamin J. Cowling, Mary Schooling

Publications and Research

Background
Testosterone therapy is increasingly promoted. No randomized placebo-controlled trial has been implemented to assess the effect of testosterone therapy on cardiovascular events, although very high levels of androgens are thought to promote cardiovascular disease.

Methods
A systematic review and meta-analysis was conducted of placebo-controlled randomized trials of testosterone therapy among men lasting 12+ weeks reporting cardiovascular-related events. We searched PubMed through the end of 2012 using “(“testosterone” or “androgen”) and trial and (“random*”)” with the selection limited to studies of men in English, supplemented by a bibliographic search of the World Health Organization trial registry. Two reviewers independently searched, …

Combatting Dental Anxiety In Patients, Gretchen Osdoba

Natural Science Student Work

Dental Anxiety is a highly debilitating condition that can keep people away from the dentist and from receiving critical care. This can lead to serious medical conditions that could have easily been prevented through proper dental care. The purpose of this paper is to describe the nature of dental fear and the different treatment options available. I will focus on helpful traits of dentists and the use of psychological treatments, nitrous oxide, anti-anxiety medications, and general anesthesia to reduce this fear. I will also discuss a comparison of a psychological treatment and an anti-anxiety medication as short-term and long-term treatment …

Synthesis And Polarographic Analysis Of A2e, Elise Rivett

Honors Program Projects

As humans age, fluorescent retinoid pigments accumulate in the retinal pigment epithelial (RPE) cells responsible for photoreceptor support. These fluorophores are of interest because they seem to contribute to diseases of the retina, particularly age-related macular degeneration, which is a leading cause of blindness in older adults in the United States and currently has no cure. One well-characterized fluorophore, A2E, can be oxidized by visible light and then generate harmful oxidative species capable of inducing programmed cell death in RPE cells. Further characterization of the redox behavior of A2E could ultimately aid the development of macular degeneration treatments designed to …

Differential Effects Of Micrornas On Glioblastoma Growth And Migration, Duane Jeansonne, Marco Pacifici, Adam Lassak, Krzysztof Reiss, Giuseppe Russo, Jovanny Zabaleta, Francesca Peruzzi

School of Medicine Faculty Publications

Glioblastoma multiforme is characterized by rapid proliferation, aggressive metastatic potential, and resistance to radio- and chemotherapy. The matricellular protein CYR61 regulates cellular proliferation and migration and is highly expressed in Glioblastomas. MicroRNAs are 22-nucleotides long RNAs that regulate gene expression post-transcriptionally. Here, we utilized the LN229 glioblastoma cell line and found that CYR61 is a target of miR-136, miR-155, and miR-634. Over-expression of miR-136 and miR-634 miRNAs negatively affected proliferation, but not migration, while expression of miR-155 reduced migration but did not affect the proliferation of LN229 cells. Investigation of the molecular mechanisms affected by expression of miR-634 revealed an …

Nitric Oxide And Its Metabolites In The Critical Phase Of Illness: Rapid Biomarkers In The Making, Asad Mian, Mayank Aranke, Nathan S. Bryan

Department of Emergency Medicine

The potential of nitric oxide (NO) as a rapid assay biomarker, one that could provide a quantum leap in acute care, remains largely untapped. NO plays a crucial role as bronchodilator, vasodilator and inflammatory mediator. The main objective of this review is to demonstrate how NO is a molecule of heavy interest in various acute disease states along the emergency department and critical care spectrum: respiratory infections, central nervous system infections, asthma, acute kidney injury, sepsis, septic shock, and myocardial ischemia, to name just a few. We discuss how NO and its oxidative metabolites, nitrite and nitrate, are readily detectable …

Is Brain-Derived Neurotrophic Factor A Possible Mechanism Underlying Risperidone Sensitization In Adolescent Rats?, Qing Shu, Gang Hu, Ming Li

Department of Psychology: Faculty Publications

Risperidone is one of the most widely used atypical antipsychotic drugs and is approved for the treatment of mental disorders (eg. schizophrenia, autism) in children and adolescents. The present study investigated the repeated treatment effect of risperidone and associated neurotropic mechanism in the phencyclidine (PCP)-induced hyperlocomotion model in adolescent rats. We examined whether repeated risperidone treatment would cause a sensitized inhibition of PCP-induced hyperlocomotion in adolescent rats, and whether such a sensitization effect was mediated by risperidone-induced alterations in Brain-Derived Neurotrophic Factor (BDNF), an important biomarker which plays a role in neuropathology of schizophrenia and action of antipsychotic medications. Male …

The Effect Of Statins On Testosterone In Men And Women, A Systematic Review And Meta-Analysis Of Randomized Controlled Trials, Mary Schooling, Shiu Lun Au Yeung, Guy Freeman, Benjamin J. Cowling

Publications and Research

Background
Statins are extensively used for cardiovascular disease prevention. Statins reduce mortality rates morethan other lipid-modulating drugs, although evidence from randomized controlled trials also suggests that statinsunexpectedly increase the risk of diabetes and improve immune function. Physiologically, statins would beexpected to lower androgens because statins inhibit production of the substrate for the local synthesis of androgens and statins’ pleiotropic effects are somewhat similar to the physiological effects of lowering testosterone, so we hypothesized that statins lower testosterone.

Methods
A meta-analysis of placebo-controlled randomized trials of statins to test the a priori hypothesis that statins lower testosterone. We searched the PubMed, …

Area Specific Self-Esteem, Values, And Adolescent Sexual Behavior, Michael Young, Joseph Donnelly, George Denny

Department of Public Health Scholarship and Creative Works

This study examined area-specific self-esteem scores by sexual behavior relative to adolescents' values concerning participation in sexual intercourse as an unmarried teenager. The sample consisted of 332 students in grades 7–12 from a Southern rural school district. Students were asked if they had ever had sexual intercourse (yes/no) and if they had participated in sexual intercourse in the last month (yes/no). Respondents also indicated on a 4-point scale their response to the statement “It is against my values to have sex as an unmarried teenager.” Data were analyzed using a 2 × 4 (behavior x values) analysis of variance for …

Inhibition Of Cholinergic Signaling Causes Apoptosis In Human Bronchioalveolar Carcinoma, Jamie K. Lau, Kathleen C. Brown, Brent A. Thornhill, Clayton M. Crabtree, Aaron M. Dom, Theodore R. Witte, W. Elaine Hardman, Christopher A. Mcnees, Cody A. Stover, A. Betts Carpenter, Haitao Luo, Yi C. Chen, Brandon S. Shiflett, Piyali Dasgupta

Biochemistry and Microbiology

Recent case-controlled clinical studies show that bronchioalveolar carcinomas (BAC) are correlated with smoking. Nicotine, the addictive component of cigarettes, accelerates cell proliferation through nicotinic acetylcholine receptors (nAChR). In this study, we show that human BACs produce acetylcholine (ACh) and contain several cholinergic factors including acetylcholinesterase (AChE), choline acetyltransferase (ChAT), choline transporter 1 (CHT1, SLC5A7), vesicular acetylcholine transporter (VAChT, SLC18A3), and nACh receptors (AChRs, CHRNAs). Nicotine increased the production of ACh in human BACs, and ACh acts as a growth factor for these cells. Nicotine-induced ACh production was mediated by α7-, α3β2-, and β3-nAChRs, ChAT and VAChT pathways. We observed that …

Challenges In Testing Genetically Modified Crops For Potential Increases In Endogenous Allergen Expression For Safety, Rakhi Panda, H. Ariyarathna, Plaimein Amnuaycheewa, Afua O. Tetteh, S. N. Pramod, Steve Taylor, B. K. Ballmer-Weber, Richard E. Goodman

Department of Food Science and Technology: Faculty Publications

Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for …

Dimethyl Sulfoxide (Dmso) Exacerbates Cisplatin-Induced Sensory Hair Cell Death In Zebrafish (Danio Rerio), Phillip M. Uribe, Melissa A. Mueller, Julia S. Gleichman, Matthew D. Kramer, Qi Wang, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger, Douglas A. Cotanche, Jonathan I. Matsui

Chemistry Faculty Publications and Presentations

Inner ear sensory hair cells die following exposure to aminoglycoside antibiotics or chemotherapeutics like cisplatin, leading to permanent auditory and/or balance deficits in humans. Zebrafish (Danio rerio) are used to study drug-induced sensory hair cell death since their hair cells are similar in structure and function to those found in humans. We developed a cisplatin dose-response curve using a transgenic line of zebrafish that expresses membrane-targeted green fluorescent protein under the control of the Brn3c promoter/enhancer. Recently, several small molecule screens have been conducted using zebrafish to identify potential pharmacological agents that could be used to protect sensory hair cells …

The Sesquiterpene Lactone Dehydroleucodine Triggers Senescence And Apoptosis In Association With Accumulation Of Dna Damage Markers, Valeria V. Constantino, Sabrina F. Mansilla, Juliana Speroni, Celina Amaya, Darío Cuello-Carrión, Daniel R. Ciocca, Manual A. Barbieri, Horacio A. Priestap, Vanessa Gottifredi, Luis A. Lopez

Department of Biological Sciences

Sesquiterpene lactones (SLs) are plant-derived compounds that display anti-cancer effects. Some SLs derivatives have a marked killing effect on cancer cells and have therefore reached clinical trials. Little is known regarding the mechanism of action of SLs. We studied the responses of human cancer cells exposed to various concentrations of dehydroleucodine (DhL), a SL of the guaianolide group isolated and purified from Artemisia douglasiana (Besser), a medicinal herb that is commonly used in Argentina. We demonstrate for the first time that treatment of cancer cells with DhL, promotes the accumulation of DNA damage markers such as phosphorylation of ATM and …