July 9, 2020

Brian Koss student highlight

Brian is a Ph.D. student starting his 5th 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).


  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:



2019-present            NIH/NCI F31 predoctoral fellowship. Epigenetic regulation of metabolic stress pathways in melanoma infiltrating lymphocytes (F31CA232464). 7th 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.


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.