• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.171-180
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• 2021

Caffeine, a methylxanthine analog of purine bases, is a compound that is largely consumed in beverages and medications for psychoactive and diuretic effects and plays many beneficial roles in neuronal stimulation and enhancement of anti-tumor immune responses by blocking adenosine receptors in higher organisms. In single-cell eukaryotes, however, caffeine somehow impairs cellular fitness by compromising cell wall integrity, inhibiting target of rapamycin (TOR) signaling and growth, and overriding cell cycle arrest caused by DNA damage. Among its multiple inhibitory targets, caffeine specifically interacts with phosphatidylinositol 3-kinase (PI3K)-related kinases causing radiosensitization and cytotoxicity via specialized intermediate molecules. Caffeine potentiates the lethality of cells in conjunction with several other stressors such as oxidants, irradiation, and various toxic compounds through largely unknown mechanisms. In this review, recent findings on caffeine effects and cellular detoxification schemes are highlighted and discussed with an emphasis on the inhibitory interactions between caffeine and its multiple targets in eukaryotic microorganisms such as budding and fission yeasts.

• Journal of Life Science
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• v.20 no.7
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• pp.977-982
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• 2010

We investigated the anti-cancer effects of two dibenzocyclooctadiene lignans, gomisin A and gomisin N, isolated from Schizandra chinensis Baill, in human promyelocytic U937 cells. Gomisin N, but not gomisin A, inhibited cell growth in a concentration-dependent manner, which was associated with the induction of G1 arrest of the cell cycle. G1 arrest induced by gomisin N was correlated with down-regulation of cyclin E, cyclin-dependent kinase (Cdk) 2 and Cdk4, and a concomitant up-regulation of Cdk inhibitors such as p16 (INK4A) and p21 (WAF1/CIP1). Furthermore, gomisin N inhibited phosphorylation of retinoblastoma protein (pRB) and p130, and expression of transcription factor E2Fs. The results indicated that growth inhibition by gomisin N is related to cell cycle arrest at G1 in U937 cells and these findings suggest that gomisin N may be a useful chemotherapeutic agent.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1383-1392
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• 2003

Apoptosis is a morphologically and biochemically district form of cell death that occurs in many different cell types in a wide variety of organisms. Albizzia julibrissin belonging the family Leguminosae has been used for the treatment of contusion, sore throat, amnesia, and insomnia in oriental traditional medicine. This study investigates whether the water extract of A. julibrissin induce apoptotic cell death in Jurkat T-acute lymphoblastic leukemia (ALL) cells. Jurkat cells were increased inhibitions of cell viability in a concentration-dependent manner by A. julibrissin. This herbal medicine also caused apoptosis as measured by cell morphology and DNA fragmentation. The capability of A. julibrissin to induce apoptosis was associated with proteolytic cleavage of specific target proteins such as poly (ADP-ribose)polymerase (PARP) and beta-catenin proteins suggesting the possible involvement of caspases. Our result showed that Bcl-2 and Bax protein levels were not changed in all A. julibrissin-treated groups compared to control group. These results suggest that A. julibrissin-mediated apoptosis is independent with Bcl-2 related signaling pathway in this cells. The purpose of the present study is also to investigate the Effect of A. julibrissin on cell cycle progression. Our results showed that G1 checkpoint related gene products (cyclin D1, cyclin dependent kinase 4, retinoblastoma, E2F1) were decreased in their protein levels in a dose-dependent manners after treatment of the extract. These results indicate that the increase of apoptotic cell death by A. julibrissin may be due to the inhibition of cell cycle progression in wild type p53-lacking Jurkat cells.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.73-84
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• 2024

A pulsed electromagnetic field (PEMF) enhances the efficacy of several anticancer drugs. Doxorubicin (DOX) is an anticancer agent used to treat various malignancies, including breast cancer. This study examined whether a PEMF increases the anticancer effect of DOX on MCF-7 human breast cancer cells and elucidated the underlying mechanisms affected by PEMF stimulation in DOX-treated MCF-7 human breast cancer cells. A cotreatment with DOX and a PEMF potentiated the reduction in MCF-7 cell viability compared to the treatment with DOX alone. The PEMF elevated DOX-induced G1 arrest by affecting cyclin-dependent kinase 2 phosphorylation and the expression of G1 arrest-related molecules, including p53, p21, cyclin E2, and polo like kinase 1. In addition, PEMF increased the DOX-induced upregulation of proapoptotic proteins, such as Fas and Bcl-2-associated X, and the downregulation of antiapoptotic proteins, including myeloid leukemia 1 and survivin. PEMF promoted the DOX-induced activation of caspases-8, -9, and -7 and poly (adenosine diphosphate-ribose) polymerase cleavage in MCF-7 cells. In conclusion, PEMF enhances the anticancer activity in DOX-treated MCF-7 breast cancer cells by increasing G1 cell cycle arrest and caspase-dependent apoptosis. These findings highlight the potential use of a PEMF as an adjuvant treatment for DOX-based chemotherapy against breast cancer.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.4
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• pp.914-922
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• 2003

Ailanthus altissima has been used to settle an upset stomach, to alleviate a fever, and as an insecticide. We reported that the water extract of A. altissima induced apoptotic cell death in HL-60 human leukemia cell line. Here, we showed the dose-dependent inhibitions of cell viability by the extract, as measured by cell morphology. The cell cycle control genes are considered to play important roles in tumorigenesis. The purpose of the present study is also to investigate the effect of A. altissima on cell cycle progression and its molecular mechanism in the cells. The level of p21 protein was increased after treatment of the extract, whereas both Bcl-2 and Bax protein levels were not changed. These results suggest that A. altissima induces apoptotic cell death via p21-dependent signaling pathway in HL-60 human leukemia cell line which delete wild type p53. G1 checkpoin related gene products tested (cyclin D3, cyclin dependent kinase 4, retinoblastoma, E2F1) were decreased in their protein levels in a dose-dependent manner after treatment of the extract. Taken together, these results indicate that the increase of apoptotic cell death by A. altissima may be due to the inhibition of cell cycle in HL-60 human leukemia cell line

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5805-5810
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• 2013

This study was conducted to analyze the molecular mechanisms responsible for anti-proliferation effects of glaucocalyxin A in cultured MCF-7 and Hs578T breast cancer cells. The concentration that reduced cell viability to 50% (IC50) after 72 h treatment was derived and potential molecular mechanisms of anti-proliferation using the IC50 were investigated as changes in cell cycle arrest and apoptosis. Gene and protein expression changes related to apoptosis were investigated by semi-quantitative RT-PCR and western blotting, respectively. Involvement of phosphorylated mitogen-activated protein kinases and JNK signaling in regulation of these molecules was characterized by western blotting. Cell viability decreased in a concentration-dependent manner and the IC50 was determined as $1{\mu}M$ in MCF-7 and $4{\mu}M$ in Hs578T cell. Subsequently, we demonstrated that the GLA-induced MCF-7 and Hst578T cell death was due to cell cycle arrest at the G2/M transition and was associated with activation of the c-jun N-terminal kinase (JNK) pathway. We conclude that GLA has the potential to inhibit the proliferation of human breast cancer cells through the JNK pathway and suggest its application forthe effective therapy for patients with breast cancer.

• Tuberculosis and Respiratory Diseases
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• v.75 no.1
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• pp.9-17
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• 2013

Background: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. Methods: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. Results: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-$G_1$ phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. Conclusion: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

• Molecules and Cells
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• v.40 no.9
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• pp.621-631
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• 2017

Vaccinia-related kinase 1 (VRK1) and VRK3 are members of the VRK family of serine/threonine kinases and are principally localized in the nucleus. Despite the crucial roles of VRK1/VRK3 in physiology and disease, the molecular and functional interactions of VRK1/VRK3 are poorly understood. Here, we identified over 200 unreported VRK1/VRK3-interacting candidate proteins by affinity purification and LC-MS/MS. The networks of VRK1 and VRK3 interactomes were found to be associated with important biological processes such as the cell cycle, DNA repair, chromatin assembly, and RNA processing. Interactions of interacting proteins with VRK1/VRK3 were confirmed by biochemical assays. We also found that phosphorylations of XRCC5 were regulated by both VRK1/VRK3, and that of CCNB1 was regulated by VRK3. In liver cancer cells and tissues, VRK1/VRK3 were highly upregulated and its depletion affected cell cycle progression in the different phases. VRK3 seemed to affect S phase progression and G2 or M phase entry and exit, whereas VRK1 affects G1/S transition in the liver cancer, which could be explained by different interacting candidate proteins. Thus, this study not only provides a resource for investigating the unidentified functions of VRK1/VRK3, but also an insight into the regulatory roles of VRK1/VRK3 in biological processes.

• The Journal of the Korean Society for Microbiology
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• v.35 no.4
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• pp.299-308
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• 2000

Recently developed cDNA microarray or DNA chip technology allows expression monitoring of expression of hundreds and thousands of genes simultaneously and provides a format for identifying genes as well as changes in their activity. In order to search for changes in gene expression after X irradiation in HL60 cells, cDNA microarray technique was done. In this study, expression of 588 human genes (including oncogenes, tumor suppressor genes, cell cycle regulator genes, intracellular signal transduction modulator genes, apoptosis related genes, transcription factor genes, growth factors and receptor genes, cytokine genes, etc) were analyzed. For cDNA microarray analysis mRNAs were extracted from control and 8 Gy-irradiated HL60 cells. As a result the changes in expression of several genes were observed. This alteration of gene expression was confirmed by reverse transcription-polymerase chain reaction. The expression of heat shock 60 KD protein, c-jun, erythroid differentiation factor, CPP32, myeloid cell nuclear differentiation antigen, MAP kinase-activated protein kinase, interleukin-8, monocyte chemotactic peptide 1 and RANTES genes was increased, but the expression of p55CDC gene was decreased after X irradiation.

• Environmental Mutagens and Carcinogens
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• v.25 no.2
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• pp.51-59
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• 2005

Overexpression of HSP25 delayed cell growth, increased the level of $p21^{waf}$, reduced the levels of cyclin D1, cylcin A and cdc2, and induced radioresistance in L929 cells. We demonstrated that extracellular regulated kinase (ERK) and MAP kinase/ERK kinase (MEK) expressions as well as their activation (phospho-forms) were inhibited by hsp25 overexpression. To confirm the relationship between ERK1/2 and hsp25-mediated radioresistance, ERK1 or ERK2 cDNA was transiently transfected into the hsp25 overexpressed cells and their radioresistance was examined. HSP25-mediated radioresistance was abolished by overexpression of ERK2, but not by overexpression of ERK1. Alteration of cell cycle distribution and cell cycle related protein expressions (cyclin D, cyclin A and cdc2) by hsp25 overexpression were also recovered by ERK2 cDNA transfection. Increase in Bc1-2 protein by hsp25 gene transfection was also reduced by subsequent ERK2 cDNA-transfection. In addition, HSP25 overexpression reduced reactive oxygen species (ROS) and increased expression of manganese superoxide dismutase (MnSOD) gene. Increased activation of NF-kB (IkB degradation) was also found in hsp25-overexpressed cells. Moreover, transfection of hsp25 antisense gene abrogated all the HSP25-mediated phenomena. To further elucidate the exact relationship between MnSOD induction and NF-kB activation, dominant negative $I-kB\alpha(I-kB\alpha-DN)$ construction was transfected to HSP25 overexpressed cells. $I-kB\alpha-DN$ inhibited HSP25 mediated MnSOD gene expression. In addition, HSP25 mediated radioresistance was blocked by $I-kB\alpha-DN$ transfection. Blockage of MnSOD with antisense oligonucleotides in HSP25 overexpressed cells, prevented apoptosis and returned the ERK1/2 activation to the control level. From the above results, we suggest for the first time that reduced oxidative damage by HSP25 was due to MnSOD-mediated down regulation of ERK1/2.