Vice Chair for Research, Department of Cell Biology
Professor, Department of Cell Biology
Adjunct Professor, Department of Obstetrics and Gynecology
Ph.D., Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, WI
B.S. cum laude, Zoology, Duke University, Durham, North Carolina
University of Oklahoma Health Sciences Center
Biomedical Research Center
975 N.E. 10th Street
Oklahoma City, OK 73104
Sensitizing Tumors to Chemotherapy: Inhibition of Gamma Glutamyl Transpeptidase
Many tumors respond initially to chemotherapy but with continued treatment become resistant to the drugs. One of the most common mechanisms by which tumors develop resistance to chemotherapy is by inactivating the drugs with glutathione. We have shown that expression of the enzyme gamma-glutamyl transpeptidase (GGT) on the surface of the tumor cell enables the tumors to use extracellular glutathione as a source of cysteine. During treatment with chemotherapy the intracellular levels of glutathione are depleted and the intracellular concentration of cysteine can become rate-limiting for glutathione synthesis. Tumor cells that express GGT are resistant to chemotherapy drugs such cisplatin. We are developing inhibitors of GGT that can be used clinically to block GGT-mediated drug resistance. We identified a novel inhibitor of GGT that is the first uncompetitive inhibitor of GGT ever reported (JBC 284:9059, 2009). We continue to develop inhibitors of GGT that can be used in the clinic.
Structural Studies of Gamma Glutamyl Transpeptidase
To aid our studies on the development of a GGT inhibitor, we collaborated with Dr. Blaine Mooers at OUHSC, crystallized human GGT and determined its structure [J. Biol. Chem., 288(44):31902-31913, 2013]. Human GGT is a heavily glycosylated, membrane bound enzyme which presented challenges in the crystallization. This is the first structure to be determined for any eukaryotic GGT. We are using this structure to aid in the design of more potent inhibitors of human GGT.
Crystal structure of human GGT. A, ribbon representation of the hGGT1 heterodimer. Shown are the large subunit (blue), the small subunit (green), and the active site Thr-381 (red). The orange oval outlines the active site cleft. For details see J. Biol. Chem., 288(44):31902-31913, 2013
Tumors that are detected at an early stage are most responsive to treatment and in some cases can be cured surgically. However, for many of the most deadly cancers including liver, pancreatic and kidney cancer there are no routine screening tests that can be used to detect the tumor at an early stage. We are developing biomarkers that can be detected in the blood or the urine. We are focusing on the differences in glycosylation between normal cells and tumor cells. We have recently completed an in-depth characterization of the N-glycans on GGT expressed in normal human kidney and liver (JBC, 2010). We are now analyzing the glycans on GGT from tumor cells to identify glycopeptides that can be used as biomarkers for early detection of these often fatal tumors.
The American Association for Cancer Research
Women in Cancer Research
The American Society for Cell Biology
Hanigan MH. Gamma-Glutamyl Transferases. In: Jez J, editor. Encyclopedia of Biological Chemistry, 3rd Edition Oxford: Elsevier Press; 2021. in press.
Terzyan SS, Nguyen LT, Burgett AWG, Heroux A, Smith CA, You Y, Hanigan MH. Crystal structures of glutathione- and inhibitor-bound human GGT1: Critical interactions within the cysteinylglycine binding site. J Biol Chem. 2020 Nov 13;. [Epub ahead of print] PubMed PMID: 33187988; PubMed Central PMCID: PMC7949050.
Cooper, A.J.L., and Hanigan, M.H. (2018) Metabolism of Glutathione S-Conjugates: Multiple Pathways In: Comprehensive Toxicology 3nd Edition. C. A. McQueen (Editor), Elsevier Press, Oxford, Chapter 10 pp. 363-406.
Terzyan, S.S., Cook, P.F., Heroux, A, and Hanigan, M.H. (2017) Structure of 6-Diazo-5-Oxo-Norleucine-Bound Human Gamma-Glutamyl Transpeptidase 1, a Novel Mechanism of Inactivation. Protein Science, 26(6):1196-1205. PMCID: PMC5441403
Terzyan, S.S., Burgett, A.W., Heroux, A., Smith, C.A., Mooers, B.H., and Hanigan, M.H. (2015) Human Gamma-Glutamyl Transpeptidase 1: Structures of the Free Enzyme, Inhibitor-Bound Tetrahedral Transition States and Glutamate-Bound Enzyme Reveal Novel Movement within the Active Site during Catalysis. J Biol Chem. 290(28):17576-86. PMCID: PMC4498091
Hanigan, M.H., Gillies, E.M., Wickham, S., Wakeham, N., and Wirsig-Wiechmann, C.R. (2015) Immunolabeling of gamma-glutamyl transferase 5 in normal human tissues reveals that expression and localization differ from gamma-glutamyl transferase 1. Histochem. Cell Biol. 143(5): 505-515. [PMCID 439375]
West, M.B., Partyka, K., Feasley, C.L., Maupin, M.A., Goppallawa, I., West, C.M., Haab, B.B. and Hanigan, M.H. (2014) Detection of Distinct Glycosylation Patterns on Human Gamma-Glutamyl Transpeptidase 1 Using Antibody-Lectin Sandwich Array (ALSA) Technology. BMC Biotechnology, Dec 6;14(1):101. PMCID: PMC4297448
Hanigan, M.H. (2014) Gamma-glutamyl transpeptidase: redox regulation and drug resistance. Advances in Cancer Research 122:103-41. PMCID:PMC4388159
West, M.B., Wickham, S., Parks, E.E., Sherry, D.M. and Hanigan, M.H. (2013) Human GGT2 Does Not Autocleave into a Functional Enzyme: A cautionary tale for interpretation of microarray data on redox signaling. Antioxidants & Redox Signaling, 19(16):1877-1888. PMCID:PMC3852618
(Image from publication used for cover of December 1, 2013 issue of Antioxidants & Redox Signaling)
West, M.B., Chen, Y., Wickham, S., Heroux, A., Cahill, K., Hanigan, M.H., Mooers, B.H.M. (2013) Novel insights into eukaryotic gamma-glutamyl transpeptidase 1 from the crystal structure of the glutamate bound human enzyme. J. Biol. Chem. 288(44):31902-31913. PMCID:PMC3814782
Wickham, S., Regan, N., West, N.B., Thai, J., Cook, P.F., Terzyan, S.S., Li, P-K., and Hanigan, M.H. (2013) Inhibition of Human Gamma-Glutamyl Transpeptidase: Development of More Potent, Physiologically Relevant, Uncompetitive Inhibitors. Biochemical Journal, 450(3):547-57. PMCID: PMC3836663
Wickham, S., Regan, N., West, M.B., Kumar, V.P., Thai, J., Li, P-K, Cook, P.F., Hanigan, M.H. (2012) Divergent Effects of Compounds on the Hydrolysis and Transpeptidation Reactions of Gamma-Glutamyl Transpeptidase. Journal of Enzyme Inhibition and Medicinal Chemistry 27, 476-489. PMCID:PMC3407035
Wickham, S., West, M.B., Cook, P.F, and Hanigan, M.H. (2011) Gamma-Glutamyl Compounds: Substrate Specificity of Gamma-Glutamyl Transpeptidase Enzymes. Analytical Biochemistry, 414:208-214. PMCID:PMC3099546
West, M.B., Wickham, S., Quinalty, L.M., Pavlovicz, R.E., Li, C. and Hanigan. M.H. (2011) Autocatalytic Cleavage of Human g-Glutamyl transpeptidase Is Highly Dependent on N-Glycosylation at Asparagine 95 J. Biol. Chem., 286 (33):28876-88. PMCID:PMC3190695
Complete List of Published Work in My Bibliography:
Profile Last Updated: June 18, 2021
Department of Cell Biology
University of Oklahoma Health Sciences Center
940 Stanton L. Young Blvd., BMSB 553
Oklahoma City, OK 73104
Phone - (405) 271-2377
Fax - (405) 271-3548