Hye-Joung Choi, PhD

Postdoctoral Fellow
Ph.D., in Pharmacology, Pusan National University, South Korea, 2005

I achieved a Ph.D. degree from Pusan National University in 2005 and then received additional training as a postdoctoral fellow at the Brain Korea 21 (BK21) Program for Medical Science, at Yonsei University College of Medicine (Seoul, Korea) in 2005-2006. In 2007, I joined the laboratory of Dr. B. T. Zhu at the University of Kansas Medical Center as a postdoctoral fellow.

Research Interests

My main research interests are: 1) studying the mechanisms of the oxidative neurodegeneration and its prevention by dietary compounds. 2) studying and the mechanism of natural anticancer agents (such as 2-methoxyestradiol and omega-3 fatty acids). I use various molecular and cellular biology and genetics as general tools in my studies. At present, I am mainly involved in the following two projects:

1. Oxidative stress-induced neurodegeneration and its prevention by natural compounds: Oxidative stress has been recognized as an important etiological factor in the development of neurodegenerative diseases. Many clinical studies have shown that increased levels of oxidative stress markers are often found in human brain tissues suffering from neurodegenerative conditions. Neuronal oxidative stress and damage can be caused by different cellular mechanisms. Using both in vitro and in vivo models, I am currently studying the molecular and cellular mechanisms as well as the signaling pathways that mediate oxidative neurodegeneration. In addition, I am also studying the role of the neuroprotective actions of certain natural compounds (such as dietary antioxidants and endogenous estrogens), with a focus on determining their mechanisms of actions.

2. Mechanism of 2-methoxyestradiol-induced cell cycle arrest and cell death. 
2-Methoxyestradiol (2ME2), a nonpolar metabolite of 17β-estradiol, has been shown to have strong anticancer effect in a variety of human cancer cell lines in vitro and in vivo, by inducing cell cycle arrest in the G2/M phase and apoptosis. I have been studying the mechanisms of 2ME2-induced cell cycle arrest and apoptosis. Recently I showed that 2ME2 selectively induces mitotic prometaphase arrest in human cancer cells, but not G2 phase arrest. Moreover, I found that during the induction of prometaphase arrest by 2ME2, cyclin B1 and Cdc2 protein levels are markedly up-regulated, and their increases play a critical role in mediating the induction of prometaphase arrest. In addition, I found that the up-regulated cyclin B1 and Cdc2 in 2ME2-induced prometaphase cells are also responsible for the increased phosphorylation of Bcl-XL, and the increased phosphorylation of this anti-apoptotic protein leads to activation of the apoptotic cell death in these cells.

Selected Publications

Choi HJ and Zhu BT [2011] Critical Role of Cyclin B1/Cdc2 Up-regulation in the Induction of Mitotic Prometaphase Arrest in Human Breast Cancer Cells Treated with 2-Methoxyestradiol. Eur J Cancer (submitted).

Fukui M, Choi HJ and Zhu BT [2011] Mechanism of Herbicide-Induced Neurotoxicity In Vitro and In Vivo: Mitochondrial Oxidative Damage as the Main Cause of Cell Death. Archives of Biochemistry and Biophysics (submitted).

Choi HJ and Zhu BT [2011] Role of Cyclin B1/Cdc2 in Mediating Bcl-2/Bcl-XL Phosphorylation and Apoptosis Following Nocodazole-Induced Mitotic Arrest. Biochemical Journal (submitted).

Choi HJ, Fukui M, Zhu BT [2011] Role of cyclin B1/Cdc2 up-regulation in the development of mitotic prometaphase arrest in human breast cancer cells treated with nocodazole. PLoS ONE 6(8): e24312.

Choi HJ, Kang KS, Fukui M, Zhu BT [2011] Critical role of the JNK-p53-GADD45α apoptotic cascade in mediating oxidative cytotoxicity in hippocampal neurons. Br J Pharmacol 162(1): 175-192.

Fukui M, Choi HJ, Zhu BT [2010] Mechanism for the protective effect of resveratrol against oxidative stress-induced neuronal death. Free Radic Biol Med 49(5): 800-813.

Fukui M, Choi HJ, Zhu BT [2009] Mechanism of glutamate-induced neurotoxicity in HT22 mouse hippocampal cells. Eur J Pharmacol 617(1-3): 1-11.

Zhou R, Fukui M, Choi HJ, Zhu BT [2009] Induction of a reversible, non-cytotoxic S-phase delay by resveratrol: implications for a mechanism of lifespan prolongation and cancer protection. Br J Pharmacol. 158(2): 462-474.

Choi HJ, Chung YS, Kim HJ, Moon UY, Choi YH, Van Seuningen I, Baek SJ, Yoon HG, Yoon JH [2009] Signal pathway of 17beta-estradiol-induced MUC5B expression in human airway epithelial cells. Am J Resp Cell Mol Biol. 40(2):168-78.