Tae-boo Choe

Learn More
Regulation of mRNA translation in mammalian cells involves the coordinated control of mammalian target of rapamycin (mTOR) signaling. At present, limited information is available on the potential relevance of mTOR regulation, although translation inhibition during oxidative and endoplasmic reticulum (ER) stress is clearly important. In this study, we show(More)
SP600125 (SAPK Inhibitor II) is reported to function as a reversible ATP competitive inhibitor of c-Jun N-terminal kinase (JNK). In the present study, we show that SP600125 induces a dose-dependent decrease in mTOR activity, as assessed by reduced phosphorylation of the downstream targets S6K1 and S6, and a significant increase in the expression of Redd1.(More)
Free radicals and reactive oxygen species (ROS), which are generated by UV irradiation, may cause serious injury to skin cell membranes, DNA and functional proteins. In addition, these agents stimulate the expressions of matrix metalloproteinases (MMPs), which can degrade most components of the extracellular matrix (ECM), including collagen. In order to(More)
Epidermal growth factor receptor (EGFR) is activated by ionizing radiation (IR), but the molecular mechanism for this effect is unknown. We have found that intracellular generation of nitric oxide (NO) by NO synthase (NOS) is required for the rapid activation of EGFR phosphorylation by IR. Treatment of A549 lung cancer cells with IR increased NOS activity(More)
Redd1, a recently discovered stress-response gene, is regulated by hypoxia via hypoxia-inducible factor 1 (HIF-1) and by DNA damage via p53/p63; however, the signaling pathway by which its expression is induced by hypoxia has not been elucidated. In the present study, we demonstrated that the expression of Redd1 in response to hypoxia (1% O(2)),(More)
TWIST1 is implicated in the process of epithelial mesenchymal transition, metastasis, stemness, and drug resistance in cancer cells, and therefore is a potential target for cancer therapy. In the present study, we found that knockdown of TWIST1 by small interfering RNA (siRNA) enhanced arsenic trioxide (ATO)- and ionizing radiation (IR)-induced cell death(More)
Nuclear protein 1 (NUPR1) was originally identified as p8, a member of the family of HMG-I/Y transcription factors induced in response to various cellular stressors. However, the signaling pathway underlying NUPR1 induction by cellular stresses remains to be established. In this study, we found that the expression of NUPR1 by various stresses induced by(More)
SUMMARY In the present study, we show that a combination of sulindac and arsenic trioxide (ATO) induces more extensive apoptosis than either drug alone in H1299 human non-small cell lung carcinoma (NSCLC) cells. Treatment with sulindac/ATO triggered three major apoptotic signaling events, namely, collapse of the mitochondrial membrane potential, release of(More)
Histone deacetylase (HDAC) inhibitors represent a promising group of anticancer agents. Treatment of cancer cells with HDAC blockers, such as suberoylanilide hydroxamic acid (SAHA), leads to the activation of apoptosis-promoting genes. To enhance proapoptotic efficiency, SAHA has been used in conjunction with radiation, kinase inhibitors, and cytotoxic(More)
INTRODUCTION Histone deacetylase inhibitors (HDACIs) induce growth arrest and apoptosis in cancer cells. In addition to their intrinsic anticancer properties, HDACIs modulate cellular responses to ionizing radiation (IR). We examined the molecular mechanism(s) associated with the radiosensitizing effects of HDACIs in human lung cancer cells. METHODS Lung(More)