Congratulations to graduate student Mary “Allie” Schleiff on her selection as the Drug Metabolism and Disposition Highlighted Trainee Author for February 2021. Allie is a Ph.D. student in the laboratory of Dr. Grover Paul Miller.​ The Drug Metabolism and Disposition article that earned her selection as a Highlighted Trainee Author is titled “Significance of Multiple Bioactivation Pathways for Meclofenamate as Revealed through Modeling and Reaction Kinetics.”

Allie is a GPIBS Ph.D. student in the Biochemistry and Molecular Biology track. She is a fourth year student in the laboratory of Dr. Grover Paul Miller.

She graduated from Henderson State University in 2017 with an Honors Bachelor of Science degree in Biochemistry and a minor in Biology, and she received a regulatory sciences certification from the UAMS Department of Environmental and Occupational Health in Spring 2020.

Research Interest Statement

My research focuses on a subset of structurally similar non-steroidal anti-inflammatory drugs (NSAIDs) known as diphenylamine NSAIDs. Diphenylamine NSAIDs are taken more than 15 million times each year in the United States, but roughly 15% of all people administered diphenylamine NSAIDs have a clinically observable case of hepatotoxicity from the compounds. Previous studies identified that diphenylamine hepatotoxicity is dependent upon metabolic bioactivation and varied depending upon minor structural modifications to the diphenylamine structural scaffold, but little work exists to identify the specific mechanisms by which diphenylamines cause hepatotoxicity. I used computational tools to identify potential diphenylamine metabolic bioactivations in seven marketed or withdrawn diphenylamine drugs and experimentally validate these computational results. Thus far, I have discovered that diphenylamine NSAIDs are preferentially bioactivated into quinone-species metabolites in variable amounts and by a variety of cytochrome P450 enzymes dependent upon minor structural modifications to the diphenylamine scaffold. I hope that results from this work can help direct future development of diphenylamine-containing drugs in the future and help identify and stratify patients at-risk following diphenylamine NSAID dosage to promote more personalized patient care.

Something Notable About Time as a Graduate Student

I am so grateful that I was trained as a fresh graduate student by Dr. Dusty Barnette. I was always dropping things, breaking things, and having the same information repeated to me over and over again and Dusty never batted an eye, scolded me, or made me feel like a burden. Specifically, I’m appreciative to him for always getting the tall things off the high shelves for me!

Career Goals

My dream job would be in a contract research organization conducting preclinical and clinical studies for pharmaceutical clients. Once I obtain my PhD, I intend to take a post-doctoral position through the Center for Drug Evaluation and Research (CDER) to enhance my regulatory experience and make myself more marketable!

Experiment or Technique You Would Most Like to Do

Nuclear magnetic resonance is a major technique used frequently in regulatory science and in the pharmaceutical industry, but my only exposure to it was for a week or so as an undergraduate in my Analytical Chemistry course. I was overwhelmed and scared of it then and I still am, though I want to change that!

Fun Fact

Cleaning is legitimately one of my favorite hobbies, so most laboratories stress me out a bit – ha. If I wasn’t working in science, I would want to be a professional home organizer.

Publications

1. Schleiff, M., Payakachat, S., Schleiff, B., Pinson, A., Flynn, N., Province, D., Boysen, G., Swamidass, S. J., Miller, G. P. “Significance of Multiple Bioactivation Pathways for Meclofenamate as Revealed through Modeling and Reaction Kinetics.”
   • Publication – Accepted, Drug Metabolism and Disposition.
2. Barnette, D., Schleiff, M., Datta, A., Flynn, N., Swamidass, S. J., Miller, G. P. “Meloxicam Methyl Group Determines Enzyme Specificity for Thiazole Bioactivation Compared to Sudoxicam.”
   • Publication – Accepted, Toxicology Letters.
3. Pinson, A., Pouncey, D., Schleiff, M., Fantegrossi, W., Prather, P., Radominska-Pandya, A., Boysen, G., Miller, G. P. “Significance of Competing Metabolic Pathways for Synthetic Cannabinoid 5F-APINACA as Revealed through Novel Reaction Kinetics.”
   • Publication – Published, Molecules. DOI: 3390/molecules25204820
4. Schleiff, M., Russell, L., Gonzalez, E., Bart, A., Broccatelli, F., Humphreys, G., Scott, E., Segall, M., Prasad, B., Hartman, J., Lauschke, V., Nwabufo, C., Takahashi, R., Durmus, S., Nichols, C., Martin, I., and Taub, M., Sodhi, J. “Advances in the Study of Drug Metabolism – Symposium Report of the 12th Meeting of the International Society for the Study of Xenobiotics (ISSX).”

• Publication – May 2020, Drug Metabolism Reviews. DOI: 1080/03602532.2020.1765793

Grants

I am partially supported by a training grant through the Pharmacology, Toxicology, and Experimental Therapeutics Department in the UAMS Graduate School entitled, “Systems Pharmacology and Toxicology” (T32GM106999).

Awards

• 2020 Third Place Bhuvan Award for Excellence in Biochemistry Graduate Research – University of Arkansas for Medical Sciences Student Research Day
• 2020 Top 30 Finalist with Honorarium – Sternfels Prize in Drug Safety Discoveries
• 2020 Pfizer Society of Toxicology National Conference Student Travel Award – Society of Toxicology Computational Toxicology Specialty Section
• 2019 First Place Oral Presentation – University of Arkansas for Medical Sciences Graduate Student Association Research Symposium
• 2019 South Central Chapter Society of Toxicology Regional Conference Travel Award
• Graduate Student Achievement Award for Selection to the Drug Metabolism Reviews Editorial Board – University of Arkansas for Medical Sciences Fall Research Award Ceremony
• Graduate Student Achievement Award for Selection to the International Society for the Study of Xenobiotics New Investigator Group – University of Arkansas for Medical Sciences Fall Research Award Ceremony
• 2019 Outstanding Graduate Student Poster Presentation – Drug Discovery and Development Colloquium
• 2019 Invited Speaker with Honorarium – Drug Metabolism and Pharmacokinetics Symposium hosted by Genentech
• 2018 MC-Bios Computational Biology Conference Travel Award – Midsouth Computational Biology and Bioinformatics Society

Duah is a GPIBS Ph.D. student in the Biochemistry and Molecular Biology track. She is starting her 5th year in the laboratories of Dr. Mark Smeltzer and Dr. David Ussery.

She has a B.S. in Pharmaceutical Sciences and a M.S. in Pharmacology from The Hebrew University of Jerusalem.

Research Interest Statement

Osteomyelitis, or bone infection, is a devastating disease with limited treatment options. My dissertation explores the molecular pathways involved in the pathogenicity of the major cause of osteomyelitis, the bacterial agent Staphylococcus aureus. We draw on genome sequencing technologies coupled with comprehensive bioinformatic analyses to define the genetic landscape of the bacterium during in vivo osteomyelitis. These studies revealed strategies the bacterium employs to survive within the bone while fending off attacks by the host. Targeting these pathways may aid in the development of therapeutics to combat S. aureus infections.

Something Notable about Time as a Graduate Student

There is a pervasive positivity across the UAMS graduate school that I’ve been fortunate to experience through interactions that spanned three departments. My co-mentors exemplified this spirit through their collaboration and commitment to guiding me on topics ranging from the intricate details of Staphylococcus aureus biology to the value of comparative genomics. Equally crucial were the bioinformaticians on our team who taught me how to critically evaluate big data. These interactions have been the highlight of the past four years.

Career Goals

I plan to remain in the genomics/bioinformatics field.

Experiment or Technique You Would Most Like to Do

Anything involving genomic engineering, particularly with CRISPR/Cas9, is always fun.

Fun fact

My husband, Ziad, and I are on a quest to visit every major National Park in the United States – our favorite so far is the Grand Canyon.

Publications

Alkam D, Jenjaroenpun P, Wongsurawat T, Udaondo Z, Patumcharoenpol P, Robeson M, et al. Genomic characterization of mumps viruses from a large-scale mumps outbreak in Arkansas, 2016. Infect Genet Evol. 2019;75:103965

Alkam D, Wongsurawat T, Jenjaroenpun P, Connor S, Hobbs C, Wassenaar TM, et al. Three Complete Genome Sequences of Genotype G Mumps Virus from the 2016 Outbreak in Arkansas, USA. Genome Announc. 2017;5(32)

Brian is a Ph.D. student starting his fifth year in the Biochemistry and Molecular Biology Department in the laboratory of Dr. Alan Tackett.

He has a B.A. in Biochemistry and Molecular Biology from Hendrix College.

Research Interest Statement

My doctoral work focuses on the dynamic interplay between the epigenetic and metabolic pathways used by T cells to sense and respond to environmental pressures. Specifically, I focused on the loss of the histone methyltransferase EZH2 (H3K27me3) in CD8+ T cells, which occurs during solid tumor infiltration and renders T cells dysfunctional. My work revealed loss of H3K27me3 leads to mitochondrial dysfunction and metabolic exhaustion, through a Cdkn2a.ARF-mediated, p53-independent mechanism. Reprogramming T cells to express a gain-of-function EZH2 mutant enhanced inhibition of tumor growth in a model of adoptive T cell therapy. My data suggest manipulation of EZH2 in T cells represents a potential strategy to protect tumor-specific T cells, which is currently unaccounted for in the clinical development of EZH2 inhibitors.

Career Goals

Once I am finished with my PhD, I plan to continue my current work and pursue early independence opportunities.

Experiment or Technique You Would Most Like to Do

This changes from time to time. However, I currently enjoy using proteomic approaches to interrogate protein turnover rates at a proteome level. I believe this approach will give us novel insights into how a cell prepares its proteome for rapid adaptation to environmental conditions.

Fun fact

My wife, Cary, and I have two boys, Bennett (5 years) and Parker (3 years).

Publications

1. Koss, B.; Shields, B. D; Taylor, E. M.; Storey, A. J.; Byrum, S. D.; et. al. Epigenetic control of Cdkn2a.Arf protects tumor-infiltrating lymphocytes from metabolic-exhaustion. Cancer Research, (accepted).
2. Trentzsch, M.; Nyamugenda, E.; Miles, T. K.; Griffin, H.; Russell, S.; Koss, B.; Cooney, K. A.; Phelan, K. D.; Tackett A. J., Iyer, S.; Boysen, G.; Baldini, G. Delivery of phosphatidylethanolamine blunts stress in hepatoma cells exposed to elevated palmitate by targeting the endoplasmic reticulum. Cell Death Discovery 6:8 (2020).
3. Taylor, E.; Koss, B.; Davis L. E.; Tackett, A. J. Histone Modifications as Biomarkers for Immunotherapy. Methods in Molecular Biology 2055:213-228 (2019).
4. Chiang, T.; Koss, B.; Su, L. J.; Washam, C. L.; Byrum, S. D.; Storey, A.; Tackett, A. J. Effect of sulforaphane and 5-aza-2’-deoxycytidine on melanoma cell growth. Medicines 6, 71 (2019).
5. Lee, T.; Christov, P. P.; Shaw, S.; Tarr, J. C.; Zhao, B.; Veerasamy, N.; Jeon, K. O.; Mills, J. J.; Bian, Z.; Sensintaffar, J. L.; al. Discovery of Potent Myeloid Cell Leukemia-1 (Mcl-1) Inhibitors That Demonstrate in Vivo Activity in Mouse Xenograft Models of Human Cancer. Journal of medicinal chemistry 62, 3971–3988 (2019).
6. Shields, B. D.; Koss, B.; Taylor, E. M.; Storey, A. J.; West, K. L.; Byrum, S. D.; Mackintosh, S. G.; Edmondson, R.; Mahmoud, F.; Shalin, S. C.; Tackett, A. J. Loss of E-Cadherin Inhibits CD103 Antitumor Activity and Reduces Checkpoint Blockade Responsiveness in Melanoma. Cancer Research 79, 1113–1123 (2019).
7. Ren, Z.; Ahn, J. H.; Liu, H.; Tsai, Y.-H.; Bhanu, N. V; Koss, B.; Allison, D. F.; Ma, A.; Storey, A. J.; Wang, P. PHF19 promotes multiple myeloma tumorigenicity through PRC2 activation. Blood blood-2019000578 (2019).
8. Shields, B. D.; Mahmoud, F.; Taylor, E. M.; Byrum, S. D.; Sengupta, D.; Koss, B.; Baldini, G.; Ransom, S.; Cline, K.; Mackintosh, S. G. Indicators of responsiveness to immune checkpoint inhibitors. Scientific Reports 7, 807 (2017).
9. Lee, T.; Bian, Z.; Zhao, B.; Hogdal, L. J.; Sensintaffar, J. L.; Goodwin, C. M.; Belmar, J.; Shaw, S.; Tarr, J. C.; Veerasamy, N.; Matulis, S. M.; Koss, B.; Fischer, M. A.; Arnold, A. L.; Camper, D. V.; Browning, C. F.; Rossanese, O. W.; Budhraja, A.; Opferman, J.; Boise, L. H.; Savona, M. R.; Letai, A.; Olejniczak, E. T.; Fesik, S. W. Discovery and biological characterization of potent myeloid cell leukemia-1 inhibitors. FEBS Letters 591, 240–251 (2017). 
10. Koss, B.; Ryan, J.; Budhraja, A.; Szarama, K.; Yang, X.; Bathina, M.; Cardone, M. H.; Nikolovska-Coleska, Z.; Letai, A.; Opferman, J. T. Defining specificity and on-target activity of BH3-mimetics using engineered B-ALL cell lines. Oncotarget 7, (2016).
11. Haverkamp, J. M.; Smith, A. M.; Weinlich, R.; Dillon, C. P.; Qualls, J. E.; Neale, G.; Koss, B.; Kim, Y.; Bronte, V.; Herold, M. J.; Green, D. R.; Opferman, J. T.; Murray, P. J. Myeloid-derived suppressor activity is mediated by monocytic lineages maintained by continuous inhibition of extrinsic and intrinsic death pathways. Immunity 41, 947–959 (2014).
12. Koss, B.; Morrison, J.; Perciavalle, R. M.; Singh, H.; Rehg, J. E.; Williams, R. T.; Opferman, J. T. Requirement for antiapoptotic MCL-1 in the survival of BCR-ABL B-lineage acute lymphoblastic leukemia. Blood 122, 1587–1598 (2013).
13. Tripathi, P.; Koss, B.; Opferman, J. T.; Hildeman, D. A. Mcl-1 antagonizes Bax/Bak to promote effector CD4(+) and CD8(+) T-cell responses. Cell death and differentiation 20, 998–1007 (2013).
14. Wang, X.; Bathina, M.; Lynch, J.; Koss, B.; Calabrese, C.; Frase, S.; Schuetz, J. D.; Rehg, J. E.; Opferman, J. T. Deletion of MCL-1 causes lethal cardiac failure and mitochondrial dysfunction. Genes and Development 27, 1351–1364 (2013).
15. Cohen, N. A.; Stewart, M. L.; Gavathiotis, E.; Tepper, J. L.; Bruekner, S. R.; Koss, B.; Opferman, J. T.; Walensky, L. D. A competitive stapled peptide screen identifies a selective small molecule that overcomes MCL-1-dependent leukemia cell survival. Chemistry and Biology 19, 1175–1186 (2012).
16. Perciavalle, R. M.; Stewart, D. P.; Koss, B.; Lynch, J.; Milasta, S.; Bathina, M.; Temirov, J.; Cleland, M. M.; Pelletier, S.; Schuetz, J. D.; Youle, R. J.; Green, D. R.; Opferman, J. T. Anti-apoptotic MCL-1 localizes to the mitochondrial matrix and couples mitochondrial fusion to respiration. Nature Cell Biology 14, 575–583 (2012).
17. Stewart, D. P.; Koss, B.; Bathina, M.; Perciavalle, R. M.; Bisanz, K.; Opferman, J. T. Ubiquitin-independent degradation of antiapoptotic MCL-1. Molecular and cellular biology 30, 3099–3110 (2010).

Complete List of Published Work:

https://www.ncbi.nlm.nih.gov/myncbi/1pihpxbtPQJQh/bibliography/public/

Grants

• 2019-present NIH/NCI F31 predoctoral fellowship. Epigenetic regulation of metabolic stress pathways in melanoma infiltrating lymphocytes (F31CA232464). 7^th percentile. $124,851
• 2019 Department of Defense Horizon Award. Epigenetic regulation of metabolic stress pathways in melanoma infiltrating lymphocytes. Recommended for funding as alternate.
• 2017-2018 Systems Pharmacology and Toxicology Graduate Fellowship, a T32 program; University of Arkansas for Medical Sciences.

Awards

• 2020 Sanofi Scholar-in-Training Award. American Association for Cancer Research (AACR), San Diego, CA
• 2020 Keystone Symposia Scholarship. Emerging Cellular Therapies: Cancer and Beyond. Banff, AB Canada
• 2019 Cancer Institute Member Spotlight. University of Arkansas for Medical Sciences, Little Rock AR.
• 2019 Graduate School Outstanding Achievement Award. University of Arkansas for Medical Sciences, Little Rock AR.
• 2018 Immuno-Oncology Innovation Award, Miltenyi Biotec. Fully paid travel to AACR 2018 and $2500 for research.

Dustyn is a Ph.D. Student in his 5th year in the Biochemistry and Molecular Biology Department. He joined the laboratory of Dr. Grover P. Miller for his research studies.

He has a B.S. in Biology from Ouachita Baptist University with minors in chemistry and art.

Research Interest Statement

A major obstacle in drug development is the occurrence of drug-induced liver injury (DILI).  DILI can cause drugs to be rejected for market approval, or it can be idiosyncratic, meaning that it may not be discovered until after market approval.

The focus of my graduate research is to study metabolic activation of drugs to form toxic metabolites, which is one of the possible causes of idiosyncratic DILI.  I am interested in the development and use of in vitro systems and computational models to serve as alternatives to in vivo trials for predicting and investigating mechanisms of drug induced hepatotoxicity.  I have conducted thorough analyses of metabolic pathways of three marketed drugs (warfarin, terbinafine, and meloxicam) with special focus on pathways that contribute to bioactivation or detoxification.  Through these efforts, I am working to establish the mechanisms that explain the idiosyncratic DILI observed for some drugs.  The clinical application of this mechanistic knowledge is to be able to predict which patients will be vulnerable to DILI based on factors that affect metabolism such as genetics, environmental exposures, and drug-drug interactions.

Something Notable about Time as a Graduate Student

Last spring, I got to go to Baltimore to present my research at the annual Society of Toxicology meeting.  Of course, the very first thing I did when I got there is take the metro train from the airport to the convention center.  When the train got to my final stop, I walked over to the door ready to get off.  I had no idea that this station was closed for construction, and the train was only stopping there because it had to wait on a crossing.  No worries though, I found this all out very quickly after the train suddenly lurched ahead again, sending my unsuspecting self toppling like a flailing rag doll straight onto the lap of some random guy sitting next to the door.  Sometimes, to only way to learn things is the hard way.

Career Goals

Once I get my Ph.D. I want to enroll in a post-doctoral position in a government research lab.  Long term, I want my career to facilitate the development, improvement, and use of in vitro systems and computational models as alternatives to in vivo for predicting and investigating mechanisms of drug induced hepatotoxicity.

Experiment or Technique You Would Most Like to Do

I always enjoy when I get to use fluorescent compounds to chemically label the metabolites that I’m studying.  There is something very fulfilling about working with brightly colored samples.

Fun fact

I like to hike.  One of my favorite trails in Arkansas is the Lost Valley Trail near Ponca.  At the hike’s end there’s a big cave with a waterfall in it, but my favorite part is actually around the halfway point.  There’s a little cave located a couple hundred feet off the main trail that my cousins and I just stumbled upon by chance one time.  You have to crawl to get into it, but once you’re in, you get to see dozens of little aquatic invertebrate fossils all over the walls and ceiling.  It looks very cool!

Publications

Comprehensive kinetic and modeling analyses revealed CYP2C9 and 3A4 determine terbinafine metabolic clearance and bioactivation.  Dustyn A. Barnette, Mary A. Davis, Noah Flynn, Anirudh S. Pidugu, S. Joshua Swamidass, and Grover P. Miller.  Biochemical Pharmacology.  October 9, 2019.  doi: 10.1016/j.bcp.2019.113661, PMID: 31605674.

CYP2C19 and 3A4 dominate metabolic clearance and bioactivation of terbinafine based on computational and experimental approaches.  Mary A. Davis, Dustyn A. Barnette, Noah R. Flynn, Anirudh S. Pidugu, S. Joshua Swamidass, Gunnar Boysen, Grover P. Miller.  Chemical Research in Toxicolgoy.  2019 Apr 10. doi: 10.1021/acs.chemrestox.9b00006, PMID: 30925039.

Lamisil (terbinafine) toxicity: Determining pathways to bioactivation through computational and experimental approaches. Dustyn A. Barnette, Mary A. Davis, Na L. Dang, Anirudh S. Pidugu, Tyler Hughes, S. Joshua Swamidass, Gunnar Boysen, Grover P. Miller.  Biochemical Pharmacology.  August 2018, 156, 10-21.  doi:  https://doi.org/10.1016/j.bcp.2018.07.043, PMID: 30076845.

Stereospecific Metabolism of R- and S-Warfarin by Human Hepatic Cytosolic Reductases.  Dustyn A. Barnette, Bryce P. Johnson, Dakota L. Pouncey, Robert Nshimiyimana, Linda Desrochers, Thomas E. Goodwin, Grover P. Miller.  Drug Metabolism and Disposition.  September 2017, 45 (9) 1000-1007.  doi: https://doi.org/10.1124/dmd.117.075929, PMID: 28646078.

Exposure cessation during adulthood did not prevent immunotoxicity caused by developmental exposure to low-level trichloroethylene in drinking water.  Kathleen M. Gilbert, Shasha Bai, Dustyn Barnette, and Sarah J. Blossom.  Toxicological Sciences.  March 2017, 157 (2): 429-437.  doi:10.1093/toxsci/kfx061, PMID: 28369519.

Evaluation of virulence and antimicrobial resistance in Salmonella enterica serovar Enteritidis isolates from humans and chicken- and egg-associated sources. Jing Han, Kuppan Gokulan, Dustyn Barnette, Sangeeta Khare, Anthony W. Rooney, Joanna Deck, Rajesh Nayak, Rossina Stefanova, Mark E. Hart, and Steven L. Foley. Foodborne Pathogens and Disease. December 2013, 10 (12): 1008-1015. doi:10.1089/fpd.2013.1518, PMID: 24102082.

Awards

UAMS Graduate Student Association Research Symposium – Third Place for Poster Presentations (Fall 2019)

Arkansas Academy of Sciences Conference – Third Place for Biochemistry/Chemistry Oral Presentation (Spring 2016)