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  1. Science & Research (NCTR)

George Hammons Ph.D.

Senior Research Scientist — Division of Biochemical Toxicology

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George Hammons, Ph.D.
(870) 543-7121
[email protected]  

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About  |  Publications  |  Lab Member


George Hammons graduated from Philander Smith College and completed his Ph.D. in chemistry/biochemistry at Harvard University. In his graduate studies, he was involved in developing approaches for elucidating enzyme-reaction mechanisms. He now works as a senior scientist at NCTR. Initially, he joined the Division of Biochemical Toxicology, later the Division of Pharmacogenetics and Molecular Epidemiology, then the Office of the Associate Director for Regulatory Activities, and recently transferred to the Division of Biochemical Toxicology. 

Research Interests:

George Hammons works as a senior investigator focused on understanding the role of cytochromes P-450 in the metabolic activation of carcinogens. Additionally, he looks to develop approaches for characterizing these enzymes and elucidating their catalytic mechanisms. He is also interested in the application of these understandings and developments to human-risk assessment. His area of focus similarly includes developing potential chemopreventive strategies with dietary agents and identifying potential early biomarkers for pancreatic cancer. He has now established a research agenda in epigenetics. This includes the role of epigenetics in disease and toxicology, particularly in the harm from tobacco smoke, as he is considered an expert in tobacco toxicology. Included in this focus, is the role of epigenetics in the regulation of enzymes involved in the activation of pro-toxicants, and most recently the role of epigenetics in the toxicity of nanoparticles.

Professional Societies/National and International Groups:

African Organization for Research and Training in Cancer (AORTIC)

American Association for Cancer Research (AACR)


Selected Publications:

Cigarette Smoke Condensate and Individual Constituents Modulate DNAMethyltransferase (DNMT) Expression in Human Liver Cells.
Xiao Y., Word B., Lyn-Cook L., Lyn-Cook B., and Hammons G.  
SAGE Open Medicine. 2015, 3.

Cytotoxicity of Chronic Exposure to Four Cigarette Smoke Condensates (CSCs) in Two Cell Lines.  disclaimer icon
Wang H., Word B., Lyn-Cook L., Yang M., Hammons G., and Lyn-Cook B. 
International J. Toxicol. 2015, 34.

Expression of Drug Transporters in Human Kidney:  Impact of Sex, Age, and Ethnicity.
Joseph S., Nicolson T., Hammons G., Word B., Green-Knox B., and Lyn-Cook B. 
Biology of Sex Differences. 2015, 6: 4.

Prolactin (PRL) and Dehydroepiandrosterone (DHEA) Levels in Women with Sytemic Lupus Eryghematous:  The Role of Extrapituitary Prolactin Promoter Polymorphism at -1149G/T.
Treadwell E., Wiley K., Word B., Patton R., Melchior W., Tolleson W., Goope N., Hammons G., and Lyn-Cook B.
J. Immunology Research. 2015. 

Effect of Cigarette Smoke Condensate on Gene Promoter Methylation in Human Lung Cells. 
Lyn-Cook L., Word B., George N., Lyn-Cook B., and Hammons G. 
Tobacco Induced Diseases. 2014, 12: 15.

Increased Expression of Toll-Like Receptors (TRLs) 7 and 9 and Other Cytokines in Systemic Lupus Erythematosus (SLE) Patients:  Ethnic Differences and Potential New Targets for Therapeutic Drugs.
Lyn-Cook B., Xie C., Oates J., Treadwell E., Word B., Hammons G., and Wiley K.
Mol. Immunology. 2014, 61: 38-43.

Cigarette Smoke Condensate Induces Differential Expression and Promoter Methylation Profiles of Critical Genes Involved in Lung Cancer in NL-20 Lung Cells In Vitro:  Short-Term and Chronic Exposure.
Word B., Lyn-Cook L., Mwamba B., Wang H., Lyn-Cook B., and Hammons G.
International J. Toxicol. 2013, 32: 23-31.

Epigenetics in Tobacco Smoke Toxicology. 
Hammons G. and Lyn-Cook B.
Current Topics in Toxicol. 2011, 7: 63-77.

Age and Gender Affect DNMT3a and DNMT3b Expression in Human Liver.
Xiao Y., Word B., Starlard-Davenport A., Haefele A., Lyn-Cook B., and Hammons G.
Cell Biology and Toxicology. 2008, 24(3): 265-272.

Indole-3-Carbinol (I3C) Modulates Expression of DNA Methyltransferases 1, 3a, and 3b in Pancreatic Cancer Cells:  Effects of Gender and a Novel (C→T) Polymorphism in the Promoter Region of DNMT 3b.
Haefele A., Word B., Xiao Y., Hammons G., and Lyn-Cook B. 
International J. Cancer Prevention. 2007, 2(4): 245-255.

Search for an Association Between the Human CYP1A2 Genotype and CYP1A2 Metabolic Phenotype.
Jiang Z., Dragin N., Jorge-Nebert L., Martin M., Guengerich F., Aklillu E., Ingelman-Sundberg M., Hammons G., Lyn-Cook B., Kadlubar F., Saldana S., Sorter M., Vinks A., Nassr N., von Richter O., Jin L., and Nebert D.  
Pharmacogenet. Genomics. 2006, 16: 359-367.

Increased Levels of NAD(P)H: Quinone Oxidoreductase 1 (NQO1) in Pancreatic Tissues from Smokers and Pancreatic Adenocarcinomas:  A Potential Biomarker of Early Damage in the Pancreas.
Lyn-Cook B., Yan-Sanders Y., Moore S., Taylor S., Word B., and Hammons G.
Cell Biology and Toxicology. 2006, 22: 73-80.

Modulation of the Constitutive Activated STAT3 Transcription Factor in Pancreatic Cancer Prevention:  Effects of Indole-3-Carbinol (I3C) and Genistein.
Lian J., Word B., Taylor S., Hammons G., and Lyn-Cook B. 
Anticancer Research. 2004, 24: 133-138.

Increased Expression of Heterogeneous Nuclear Ribonucleoprotein A2/B1 (hnRNP) in Pancreatic Tissue from Smokers and Pancreatic Tumor Cells.
Yan-Sanders Y., Hammons G., and Lyn-Cook B.
Cancer Letters. 2002, 183: 215-220.

Specific Site Methylation in the 5’-Flanking Region of CYP1A2: Interindividual Differences in Human Livers.
Hammons G., Sanders Y., Jin B., Blann E., Kadlubar F., and Lyn-Cook B.
Life Sciences. 2001, 69: 839-845.

Increased Expression of Hepatic DNA Methyltransferase in Smokers.
Hammons G., Yan Y., Lopatina N., Jin B., Wise C., Blann E., Poirier L., Kadlubar F., and Lyn-Cook B.   
Cell Biology and Toxicology. 1999, 15: 389-394.

Chemopreventive Effects of Tea Extracts and Various Components on Human Pancreatic and Prostate Tumor Cells In Vitro
Lyn-Cook B., Rogers T., Yan Y., Blann E., Kadlubar F., and Hammons G.
Nutrition and Cancer. 1999, 35: 78-84.

Effects of Chemoprotective Agents on the  Metabolic Activition of the Carcinogenic Arylamines PhIP and 4-Aminobiphenyl in Human and Rat Liver Microsomes. 
Hammons G., Fletcher J., Stepps K., Smith E., Balentine D., Harbowy M., and Kadlubar F.
Nutrition and Cancer. 1999, 33: 46-52.  

Metabolism of Carcinogenic Heterocyclic  and  Aromatic  Amines  by Recombinant Human Cytochrome P450 Enzymes.
Hammons G., Milton D., Stepps K., Guengerich F., Tukey R., and Kadlubar F. 
Carcinogenesis. 1997, 18: 851-854.

Increased DT-Diaphorase Activity in Transformed and Tumorigenic Pancreatic Acinar Cells. 
Hammons G., Warren G., Blann E., Nichols J., and Lyn-Cook B.
Cancer Letters. 1995, 96: 9-14.

Modification of Cytochrome P450 1A2 Enzymes by the Mechanism Based Inactivator 2 Ethynylnaphthalene and the Photoaffinity Label 4 Azido-Biphenyl.
Yun C., Hammons G., Jones G., Martin M., Hopkins N., Alworth W., and Guengerich F. 
Biochemistry. 1992, 31: 10556-10563.

4 Aminobiphenyl Hemoglobin Adduct Formation as an Index of In Vivo N Oxidation by Hepatic Cytochrome
Hammons G., Dooley K., and Kadlubar F. 
Chemical Res. Toxicol. 1991, 4: 144-147.

2 Ethynyl- Naphthalene as a Mechanism Based Inactivator of the Cytochrome P 450-Catalyzed N Oxidation of 2 Naphthylamine. 
Hammons G., Alworth W., Hopkins N., Guengerich F., and Kadlubar F.
Chemical Res. Toxicol. 1989, 2: 367-374.

Metabolic Oxidation of Carcinogenic Arylamines by Rat, Dog, and Human Hepatic Microsomes and by Purified Flavin Containing and Cytochrome P 450 Monooxygenases. 
Hammons G., Guengerich F., Weis C., Beland F., and Kadlubar F.
Cancer Res. 1985, 45: 3578-3585.

Proton Exchange Reactions of Acetone and Butanone:  Resolution of Catalysis by Acetoacetate Decarboxylase. 
Hammons G., Westheimer F., Nakaoka K., and Kluger R.
J. American Chemical Society. 1975, 97: 1568-1573.

Lab Member:

Marta Pogribna
Research Biologist
(870) 543-7121
[email protected]

Contact Information
George Hammons
(870) 543-7121
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