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Selected Publications

Stem Cell Toxicology Group

  1. Ngalame NO, Waalkes MP, Tokar EJ. Silencing KRAS Overexpression in Cadmium-Transformed Prostate Epithelial Cells Mitigates Malignant Phenotype. Chemical research in toxicology 2016 [Abstract]
  2. Sharma NK, Kumar A, Kumari A, Tokar EJ, Waalkes MP, Bortner CD, Williams J, Mason RP, Sinha BK. Nitric Oxide Down-Regulates Topoisomerase I and Induces Camptothecin Resistance in Human Breast MCF-7 Tumor Cells. PloS one 10(11):- , 2015. [Abstract]
  3. Person RJ, Olive Ngalame NN, Makia NL, Bell MW, Waalkes MP, Tokar EJ. Chronic inorganic arsenic exposure in vitro induces a cancer cell phenotype in human peripheral lung epithelial cells.Toxicology and applied pharmacology  286(1):36-43, 2015. [Abstract]
  4. Qu W, Waalkes MP. Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure. Toxicology and applied pharmacology 283(3):267-274, 2015. [Abstract]
  5. Xu Y, Tokar EJ, Waalkes MP. Arsenic-induced transformation of human breast epithelia is estrogen receptor-independent but involves aromatase activation. Arch Toxicol 88(2): 263-274, 2014. [Abstract]
  6. Ngalame NN, Tokar EJ, Person RJ, Xu Y, Waalkes MP. Aberrant microRNA expression likely controls RAS oncogene activation during malignant transformation of human prostate epithelial and stem cells by arsenic. Toxicol. Sci. 138(2): 268-277, 2014. [Abstract]
  7. Waalkes MP, Qu W, Tokar EJ, Kissling GE, Dixon D. Lung tumors in mice induced by "whole life" inorganic arsenic exposure at human relevant doses. Arch. Toxicol. 88(8): 1619-1629, 2014. [Abstract]
  8. Ngalame NN, Tokar EJ, Person RJ, Waalkes MP. Silencing KRAS overexpression in arsenic-transformed prostate epithelial and stem cells partially mitigates malignant phenotype. Toxicol. Sci. 142(2): 489-496, 2014 [Abstract]
  9. Tokar EJ, Person RJ, Ngalame NN, Qu W, Waalkes, MP. Oxidative Stress and the Inorganic Carcinogens, Chapter TBD; In Kehrer, Roberts, Lars-Oliver (Eds): Oxidative Stress in Applied Basic Research and Clinical Practice, Springer (Humana Press), (In Press) 2014.
  10. Tokar EJ, Waalkes MP. Cancer Induced by Exposure to Arsenicals in Animals, Chapter 19; In; States, J. C. (Ed): Arsenic: Exposure Sources, Health Risks and Mechanisms of Toxicity, John Wiley & Sons, Inc. (In Press) 2014.
  11. Tokar EJ, Xu Y, Waalkes, MP. Stem Cell Targeting and Alteration by Arsenic, Chapter 17; In; States, J. C. (Ed): Arsenic: Exposure Sources, Health Risks and Mechanisms of Toxicity, John Wiley & Sons, Inc. (In Press) 2014.
  12. Tokar EJ, Kojima C, Waalkes MP. Methylarsonous acid causes oxidative DNA damage in cells independent of the ability to biomethylate inorganic arsenic. Archives of Toxicology, 88(2):249-261, 2014. [Abstract]
  13. Tokar EJ, Boyd W, Freedman JH, Waalkes MP. Toxic Effects of Metals, Chapter 23; In: Klaassen, C. D. (Ed): Casarett and Doull's Toxicology: The Basic Science of Poisons, 8th Edition, McGraw-Hill Medical, New York, 2013.
  14. Severson PL, Tokar EJ, Vrba L, Waalkes MP, Futscher BW. Coordinate H3K9 and DNA methylation silencing of ZNFs in toxicant-induced malignant transformation. Epigenetics 8(10): 1080-1088, 2013 [Abstract]
  15. Tokar EJ, Person RJ, Sun Y, Perantoni AO, Waalkes MP. Chronic exposure of renal stem cells to inorganic arsenic induces a cancer phenotype. Chemical research in toxicology, 26(1):96-105, 2013. [Abstract]
  16. Person RJ, Tokar EJ, Xu Y, Orihuela R, Ngalame NN, Waalkes MP. Chronic cadmium exposure in vitro induces cancer cell characteristics in human lung cells. Toxicology and Applied Pharmacology 273(2):281-8, 2013. [Abstract]
  17. Xu Y, Tokar EJ, Person RJ, Orihuela RG, Ngalame NN, Waalkes MP. Recruitment of normal stem cells to an oncogenic phenotype by noncontiguous carcinogen-transformed epithelia depends on the transforming carcinogen. Environmental health perspectives 121(8):944-950, 2013. [Abstract]
  18. Qu W, Pi J, Waalkes MP. Metallothionein blocks oxidative DNA damage in vitro. Archives of Toxicology, 87(2):311-321, 2013. [Abstract]
  19. Chatterjee S, Ganini D, Tokar EJ, Kumar A, Das S, Corbett J, Kadiiska M, Waalkes M, Diehl AM, Mason RP. Leptin is key to peroxynitrite-mediated oxidative stress and Kupffer cell activation in experimental non-alcoholic steatohepatitis. Journal of hepatology 2013 58(4):778-784. [Abstract]
  20. Severson PL, Tokar EJ, Vrba L, Waalkes MP, Futscher BW. Agglomerates of aberrant DNA methylation are associated with toxicant-induced malignant transformation. Epigenetics: official journal of the DNA Methylation Society 7(11):1238-1248, 2012. [Abstract]
  21. Xu Y, Tokar EJ, Sun Y, Waalkes MP. Arsenic-transformed malignant prostate epithelia can convert noncontiguous normal stem cells into an oncogenic phenotype. Environmental health perspectives. 120(6):865-71, 2012. [Abstract]
  22. Zhan, L, Zhang, H, Zhang, Q, Woods, CG, Chen Y, Xue P, Dong J, Tokar, EJ, Xu, y, Hou, Y, Fu, J, Yarborough, K, Wang, A, Qu, W, Waalkes, MP, Andersen, ME, Pi, J. Regulatory role of KEAP1 and NRF2 in PPARγ expression and chemoresistance in human non-small-cell lung carcinoma cells. Journal of free radicals in biology & medicine  53(4):758-68, 2012. [Abstract]
  23. Tokar EJ, Diwan BA, Thomas DJ, Waalkes MP. Tumors and proliferative lesions in adult offspring after maternal exposure to methylarsonous acid during gestation in CD1 mice. Archives of toxicology  86(6):975-82, 2012. [Abstract]
  24. Qu W, Tokar EJ, Kim AJ, Bell MW, Waalkes MP. Chronic cadmium exposure in vitro causes acquisition of multiple tumor cell characteristics in human pancreatic epithelial cells. Environmental health perspectives.  120(9):1265-71, 2012. [Abstract]
  25. Shimada H, Hashiguchi T, Yasutake A, Waalkes MP, Imamura Y. Sexual dimorphism of cadmium-induced toxicity in rats: involvement of sex hormones. Archives of toxicology 2012 86(9):1475-80. [Abstract]
  26. Sun Y, Tokar EJ, Waalkes MP. Overabundance of Putative Cancer Stem Cells in Human Skin Keratinocyte Cells Malignantly Transformed by Arsenic. Toxicological Sciences 125(1):20-29, 2012. [Abstract]
  27. Sun Y., Kojima C., Chignell C., Mason R., Waalkes M.P.: Arsenic transformation predisposes human skin keratinocytes to UV-induced DNA damage yet enhances their survival apparently by diminishing oxidant response. Toxicology and applied pharmacology. 255(3):242-250, 2011. [Abstract]
  28. Qu, W., Cheng, L., Dill, A.L., Saavedra, J.E., Hong, S.Y., Keefer, L.K., and Waalkes, M. P.: Nitric oxide donor, V-PROLI/NO, provides protection against arsenical induced toxicity in rat liver cells: Requirement for Cyp1a1.  Chem Biol Interact. 193: 88-96, 2011. [Abstract]
  29. Tokar, E.J., Benbrahim-Tallaa, L., and Waalkes, M. P.: Metal ions in human cancer development.  Met Ions Life Sci. 8: 375-401, 2011. [Abstract]
  30. Tokar, E. J., Qu, W., and Waalkes, M. P.: Arsenic, stem cells, and the developmental basis of adult cancer.  Toxicol Sci. 120 Suppl 1: S192-203, 2011. [Abstract]
  31. Tokar, E.J., Diwan, B.A., Ward, J.M., Delker, D.A., and Waalkes, M.P.: Carcinogenic effects of "whole-life" exposure to inorganic arsenic in CD1 mice.  Toxicol Sci. 119: 73-83, 2011. [Abstract]
  32. Zhao, R., Hou, Y., Xue, P., Woods, C.G., Fu, J., Feng, B., Guan, D., Sun, G., Chan, J. Y., Waalkes, M. P., Andersen, M. E., and Pi, J.: Long isoforms of NRF1 contribute to arsenic-induced antioxidant response in human keratinocytes. Environ Health Perspect. 119(1): 56-62, 2011. [Abstract]
  33. Tokar, E. J., Benbrahim-Tallaa, L., Ward, J.M., Lunn, R., Sams, R. L., 2nd, and Waalkes, M. P.: Cancer in experimental animals exposed to arsenic and arsenic compounds.  Crit Rev Toxicol. 40: 912-927, 2010. [Abstract]
  34. Tokar, E. J., Diwan, B. A., and Waalkes, M. P.: Early life inorganic lead exposure induces testicular teratoma and renal and urinary bladder preneoplasia in adult metallothionein-knockout mice but not in wild type mice.  Toxicology. 276: 5-10, 2010. [Abstract]
  35. Tokar, E. J., Diwan, B.A., and Waalkes, M.P.: Arsenic exposure in utero and nonepidermal proliferative response in adulthood in Tg.AC mice.  Int J Toxicol. 29: 291-296, 2010. [Abstract]
  36. Tokar, E. J., Qu, W., Liu, J., Liu, W., Webber, M. M., Phang, J., and Waalkes, M. P.: Arsenic-specific stem cell selection during malignant transformation.  J. Natl. Cancer Inst. 102: 638-649, 2010. [Abstract]
  37. Tokar, E. J., Diwan, B. A., and Waalkes, M. P.: Arsenic exposure transforms human epithelial stem/progenitor cells into a cancer stem-like phenotype.  Envron. Health Perspect. 118: 108-115, 2010. [Abstract]
  38. Benbrahim-Tallaa, L., Tokar, E. J., Diwan, B. A., Dill, A. L., Coppin, J. F., and Waalkes, M. P.: Cadmium malignantly transforms normal human breast epithelial cells into a basal-like phenotype. Envron. Health Perspect. 117: 1847-1852, 2009. [Abstract]
  39. Kojima, C., Ramirez, D. C., Tokar, E. J., Himeno, S., Drobná, Z., Stýblo, M., Mason, R. P., and Waalkes, M. P.: Requirement of arsenic biomethylation for oxidative DNA damage.  J. Natl. Cancer Inst. 101: 1670-1681, 2009. [Abstract]
  40. Nelson, G. M., Ahlborn, G. J., Allen, J. W., Ren, H., Corton, J. C., Waalkes, M. P., Kitchin, K. T., Diwan, B. A., Knapp, G., and Delker, D. A.: Transcriptional changes associated with reduced spontaneous liver tumor incidence in mice chronically exposed to high dose arsenic.  Toxicology. 266: 6-15, 2009. [Abstract]
  41. Zuo, P., Qu, W., Cooper, R. N., Goyer, R. A., Diwan, B. A., and Waalkes M. P.: Potential role of alpha-synuclein and metallothionein in lead-induced inclusion body formation.  Toxicol. Sci. 111: 100-108, 2009. [Abstract]
  42. Sun, Y., Pi, J., Wang, X., Tokar, E. J., Liu, J., and Waalkes, M. P.: Aberrant cytokeratin expression during arsenic-induced acquired malignant phenotype in human HaCaT keratinocytes consistent with epidermal carcinogenesis.  Toxicology. 262: 162-170, 2009. [Abstract]
  43. Liu, J., Zhou, Z. X., Zhang, W., Bell, M. W., and Waalkes, M. P.: Changes in hepatic gene expression in response to hepatoprotective levels of zinc.  Liver Int. 29: 1222-1229, 2009. [Abstract]
  44. Shimada, H., Narumi, R., Nagano, M., Yasutake, A., Waalkes, M. P., and Imamura, Y.: Strain difference of cadmium-induced testicular toxicity in inbred Wistar-Imamichi and Fischer 344 rats.  Arch Toxicol. 83: 647-652, 2009. [Abstract]
  45. Ahlborn, G. J., Nelson, G. M., Grindstaff, R. D., Waalkes, M. P., Diwan, B. A., Allen, J. W., Kitchin, K. T., Preston, R. J., Hernandez-Zavala, A., Adair, B., Thomas, D. J., and Delker, D. A.: Impact of life stage and duration of exposure on arsenic-induced proliferative lesions and neoplasia in C3H mice.  Toxicology. 262: 106-113, 2009. [Abstract]
  46. Pi, J., Diwan, B. A., Sun, Y., Qu, W., He, Y., Styblo, M., Liu, J., and Waalkes, M. P.: Arsenic-induced malignant transformation of human keratinocytes: Involvement of Nrf2.  Free Rad. Biol. Med.  45: 651-658, 2008. [Abstract]
  47. Waalkes, M. P., Liu, J., Germolec, D. R., Trempus, C. S., Cannon, R. E., Tokar, E. J., Tennant, R. W., Ward, J. M., and Diwan, B. A.: Arsenic exposure in utero exacerbates skin cancer response in adulthood with contemporaneous distortion of tumor stem cell dynamics. Cancer Res. 68: 8278-8285, 2008. [Abstract]
  48. Coppin, J. F., Qu, W., and Waalkes, M. P.: Interplay between cellular methyl metabolism and adaptive efflux during oncogenic transformation from chronic arsenic exposure in human cells. J. Biol. Chem. 283: 19342-19350, 2008. [Abstract]
  49. Pi, J., Bai, Y., Reece, J. M., Williams, J., Liu, D., Freeman, M. L., Fahl, W. E., Shugar, D., Liu, J., Collins, S., and Waalkes, M. P.: Molecular mechanism of Nrf2 activation and degradation:  Role of sequential phosphorylation by protein kinase CK2.  Free Rad. Biol. Med. 42: 1797-1806, 2007. [Abstract]
  50. Benbrahim-Tallaa, L., Waterland, R. A., Webber, M. M., and Waalkes, M. P.:  Tumor suppressor gene inactivation during cadmium-induced malignant transformation of human prostate cells correlates with over-expression of de novo DNA methyltransferase.  Environ. Health Perspect. 115: 1454-1459, 2007. [Abstract]
  51. Qu, W., Ke, H., Pi, J., Broderick, D. K., French, J. E., Webber, M. M., and Waalkes, M. P.: Acquisition of apoptotic resistance in cadmium-transformed human prostate epithelial cells: Bcl-2 overexpression blocks the activation of JNK signal transduction pathway.  Environ. Health Perspect. 115: 1094-1100, 2007. [Abstract]
  52. Benbrahim-Tallaa, L., Webber, M. M., and Waalkes, M. P.: Mechanisms of acquired androgen independence during arsenic-induced malignant transformation of human prostate epithelial cells. Environ. Health Perspect. 115: 243-147, 2007. [Abstract]
  53. Leslie, E. M., Liu, J., Klaassen, C. D., and Waalkes, M. P.: Acquired cadmium resistance in metallothionein-I/II (-/-) knockout cells: Role of T-type calcium channel Ca?1G in cadmium uptake.  Mol. Pharmacol. 69: 629-639, 2006. [Abstract]
  54. Waalkes, M. P., Liu, J., Kasprzak, K. S., and Diwan, B. A.: Hypersusceptibility to cisplatin carcinogenicity in metallothionein-I/II double knockout mice: Production of hepatocellular carcinoma at clinically relevant doses. Int. J. Cancer. 119: 28-32, 2006. [Abstract]
  55. He, Y.-Y., Pi, J., Huang, J.-L., Diwan, B. A., Waalkes, M. P., and Chignell, C. F.: Chronic UVA irradiation of human HaCaT keratinocytes induces malignant transformation associated with acquired apoptotic resistance.  Oncogene 25:3680-3688, 2006. [Abstract]
  56. Waalkes, M. P., Liu, J., Ward, J. M., Powell, D. A., and Diwan, B. A.: Urogenital carcinogenesis in female CD1 mice induced by in utero arsenic exposure is exacerbated by postnatal diethylstilbestrol treatment.  Cancer Res.  66: 1337-1345, 2006. [Abstract]
  57. Benbrahim-Tallaa, L., Waterland, R. A., Styblo, M., Achanzar, W. E., Webber, M. M., and Waalkes, M. P.: Molecular events associated with arsenic-induced malignant transformation of human prostate epithelial cells: Aberrant genomic DNA methylation and K-ras oncogene activation. Toxicol. Appl. Pharmacol. 206: 288-298, 2005. [Abstract]
  58. Qu, W., Diwan, B. A., Reece, J. M., Bortner, C. D., Pi, J., Liu, J., and Waalkes, M. P.: Cadmium-induced malignant transformation in rat liver cells:  Role of aberrant oncogene expression and minimal role of oxidative stress.  Int. J. Cancer 114: 346-355, 2005. [Abstract]
  59. Benbrahim-Tallaa, L., Webber, M. M., and Waalkes, M. P.: Acquisition of androgen-independence by human prostate epithelial cells during arsenic-induced malignant transformation. Environ. Health Perspect. 113: 1134-1139, 2005. [Abstract]
  60. Pi, J., Yamauchi, H., Sun, G., Yoshida, T., Aikawa, H., Fujimoto, W., Isso, H., Cui, R., Waalkes, M.., and Kumagai, Y.: Vascular dysfunction in patients with chronic arsenosis can be reversed by reduction in arsenic exposure.  Environ. Health Prespect. 113: 339-341, 2005. [Abstract]
  61. Chen, H., Li, S., Liu, J., Diwan, B. A., Barrett, J. C., and Waalkes, M. P.: Chronic inorganic arsenic exposure induces hepatic global and individual gene hypomethylation: Implications for arsenic hepatocarcinogenesis. Carcinogenesis 25: 1779-1786, 2004. [Abstract]
  62. Leslie, E. M., Haimeur, A., and Waalkes, M. P.: Arsenic transport by the human multidrug resistance protein 1 (MRP1/ABCC1):  Evidence that a  tri-glutathione conjugate is  required.  J. Biol. Chem. 279: 32700-32708, 2004. [Abstract]