• Archives of Pharmacal Research
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• v.29 no.1
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• pp.40-45
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• 2006

Several diacetoxy acetal analogues have been synthesized from santonin and assessed for their ability of inducing or enhancing the differentiation of human HL-60 leukemia cells. The compounds themselves had little effect on HL-60 cell differentiation. However, three analogues, 2a, 3a, and 5b, synergistically enhanced 1,25-dihydroxyvitamin $D_3[1,25-(OH)_2D_3]-induced$ HL-60 cell differentiation when combined with 5 nM of dihydroxyvitamin $D_3[1,25(OH)_2O_3]$, a well-known differentiation inducer. Especially, the compound 5b profoundly enhanced the $1,25-(OH)2O_3]-induced$ HL-60 cell differentiation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2447-2451
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• 2013

Objective: To study changes of tumor associated carbohydrate antigen (TACAs) expression and mRNA levels for tumor associated glycosyltransferases, and assess subcellular localizations of N-acetyl galactosyltransferases (GalNAc-Ts) in the K562 leukemia cell line after imatinib treatment. Methods: RT-PCR was performed to analyze the expression of glycosyltransferases which synthesize O-glycan in tumor-associated carbohydrate antigens (TCTAs). The expression of Tn antigen, T antigen and sialyl T antigen on K562 cell membranes was measured by flow cytometry after treatment with different concentrations of imatinib. Co-localization of GalNAc-Ts and ER (endoplasmic reticulum) was determined by confocal laser scanning microcopy. Results: Transcript expression levels of several glycosyltransferases related to TCTAs were decreased after imatinib ($0-0.3{\mu}M$) treatment. Expression of Tn antigen and T antigen was increased while that of sialyl T antigen was decreased. Co-localization of GalNAc-Ts and ER was reduced by $0.2{\mu}M$ of imatinib. Conclusion: Imatinib inhibited the expression of O-glycan related TACAs and several related glycosyltransferases, while decreasing the co-localization of GalNAc-Ts and ER and normalizing O-glycosylation in the K562 human leukemia cell.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.241-246
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• 2014

Acute promyelocytic leukemia (APL) is a cancer of the blood. Although electron beam (EB) irradiation is used with other anti-cancer agents, EB irradiation can be harmful to normal tissues around the cancer. In the present study, we evaluate the differential cytotoxic effect of EB irradiation with other molecules, including TNF-${\alpha}$, on DMSO-treated HL-60 cells and HL-60 cells. HL-60 cells are the human promyleocytic leukemia cell line and are differentiated by DMSO. DMSO-treated HL-60 cells are considered to be normal granulocytic cells. In these results, TNF-${\alpha}$ may be used as the potential agent for the treatment of blood cancer without side effects in low dose of EB irradiation therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3817-3825
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• 2015

Background: The human protein methyl-transferase DOT1L catalyzes the methylation of histone H3 on lysine 79 (H3K79) at homeobox genes and is also involved in a number of significant processes ranging from gene expression to DNA-damage response and cell cycle progression. Inhibition of DOT1L activity by shRNA or small-molecule inhibitors has been established to prevent proliferation of various MLL-rearranged leukemia cells in vitro, establishing DOT1L an attractive therapeutic target for mixed lineage leukemia (MLL). Most of the drugs currently in use for the MLL treatment are reported to have low efficacy, hence this study focused on various natural compounds which exhibit minimal toxic effects and high efficacy for the target receptor. Materials and Methods: Structures of human protein methyl-transferase DOT1L and natural compound databases were downloaded from various sources. Virtual screening, molecular docking, dynamics simulation and drug likeness studies were performed for those natural compounds to evaluate and analyze their anti-cancer activity. Results: The top five screened compounds possessing good binding affinity were identified as potential high affinity inhibitors against DOT1L's active site. The top ranking molecule amongst the screened ligands had a Glide g-score of -10.940 kcal/mol and Glide e-model score of -86.011 with 5 hydrogen bonds and 12 hydrophobic contacts. This ligand's behaviour also showed consistency during the simulation of protein-ligand complex for 20000 ps, which is indicative of its stability in the receptor pocket. Conclusions: The ligand obtained out of this screening study can be considered as a potential inhibitor for DOT1L and further can be treated as a lead for the drug designing pipeline.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3715-3721
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• 2015

Leukemia is a clonal disorder with blocked normal differentiation and cell death of hematopoietic progenitor cells. Traditional modalities with most used radiation and chemotherapy are nonspecific and toxic which cause adverse effects on normal cells. Differentiation inducing therapy forcing malignant cells to undergo terminal differentiation has been proven to be a promising strategy. However, there is still scarce of potent differentiation inducing agents. We show here that Angelica sinensis polysaccharide (ASP), a major active component in Dong quai (Chinese Angelica sinensis), has potential differentiation inducing activity in human chronic erythro-megakaryoblastic leukemia K562 cells. MTT assays and flow cytometric analysis demonstrated that ASP inhibited K562 cell proliferation and arrested the cell cycle at the G0/G1 phase. ASP also triggered K562 cells to undergo erythroid differentiaton as revealed by morphological changes, intensive benzidine staining and hemoglobin colorimetric reaction, as well as increased expression of glycophorin A (GPA) protein. ASP induced redistribution of STAT5 protein from the cytoplasm to the nucleus. Western blotting analysis further identified that ASP markedly sensitized K562 cells to exogenous erythropoietin (EPO) by activating EPO-induced JAK2/STAT5 tyrosine phosphorylation, thus augmenting the EPO-mediated JAK2/STAT5 signaling pathway. On the basis of these findings, we propose that ASP might be developed as a potential candidate for chronic myelogenous leukemia inducing differentiation treatment.

• Journal of Life Science
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• v.19 no.2
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• pp.249-255
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• 2009

Esculetin, a coumarin compound, has been known to inhibit proliferation and induce apoptosis in several types of human cancer cells. However, the molecular mechanisms involved in esculetin-induced apoptosis are still uncharacterized in human leukemia cells. In this study, we have investigated whether esculetin exerts anti-proliferative and apoptotic effects on human leukemia U937 cells. It was found that esculetin could inhibit cell viability in a time-dependent manner, which was associated with the induction of apoptotic cell death such as increased populations of apoptotic- sub G1 phase. Apoptosis of U937 cells by esculetin was associated with an inhibition of Bcl-2/Bax binding activity, formation of tBid, down-regulation of X-linked inhibitor of apoptotic protein (XIAP) expression, and up-regulation of death receptor 4 (DR4) and FasL expression. Esculetin treatment also induced the degradation of ${\beta}$-catenin and DNA fragmentation factor 45/inhibitor of caspase-activated DNase (DFF45/ICAD). Furthermore, a caspase-3 specific inhibitor, z-DEVD-fmk, significantly inhibited sub-G1 phase DNA content, morphological changes and degradation of ${\beta}$-catenin and DEE45/ICAD. These results indicated that a key regulator in esculetin-induced apoptosis was caspase-3 in human leukemia U937 cells.

• Toxicological Research
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• v.19 no.3
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• pp.197-203
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• 2003

Apicidin, a histone-deacetylase inhibitor, has been successfully used to inhibit the growth of cancer cells. In this study, the apoptotic potential and mechanistic insights of apicidin were investigated in human myeloid leukemia U937 cells. Treatment of U937 cells with apicidin resulted in a decrease of cell viability with apoptotic characteristics, including chromatin condensation and ladder-pattern fragmentation of genomic DNA. Apicidin converted the procaspase-3 protease to catalytically active effector protease, resulting in subsequent cleavage of poly (ADP-ribose) polymerase (PARP) and inhibitor of caspase-activated deoxyribonuclease (ICAD). In addition, apicidin induced the activation of caspase-9 protease and the cytosolic release of mitochondrial cytochrome c with mitochon-drial membrane potential transition. Moreover, apicidin transiently increased the expression of Fas and Fas ligand proteins. Taken together, the results suggest that apicidin induces apoptosis of U937 cells through activation of intrinsic caspase cascades and Fas/FasL system with mitochondrial dysfunction.

• The Korean Journal of Zoology
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• v.7 no.1
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• pp.29-32
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• 1964

A study on chromosome of leucocytes in blood cultures derived from 6 normal Korean was performed . Exact chromosome counts were carried out on 205 cells in male, 211 in female , of which 86.05% revealed a chormosome mordal number of 46. On the basis of relative chromosome lengths and position of centromeres, the Karyotype that the human chromosomes were classified into 7 groups with 22 airs of autosome and one pair of sex chromosome was determined accoridng to the method of denver report. The chromosome number on metaphase was observed in short term cultures of leucocytes from the peripheral blood of 2 patients with chronic granulocytic leukemia and 1 patient with acute granulocitic leukemia . and the chromosome morpholoogy was also investigated in one acute leukemic patient. In all leukemic cases the leucocytes showed the constant value of 46 in the stem -line of chormosome number. But the frequency of cells with 46 chromosomes appeared in the 3 cases was 67.30% in average with a slightly higher range in hypo-andhyper-diploid chromosome numbers than in normal human, The idiogram analysis did not show any abnormality of chromosome in acute leukemic cells.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.787-791
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• 2009

In the course of screening for substances that inhibit etoposide (10 ${\mu}g$/ml)-induced apoptosis in human leukemia U937 cells, fungal strain F000120, which exhibits potent inhibitory activity, was selected. The active compound was purified from an ethyl acetate extract of the microorganism by Sep-pak $C_{18}$ column chromatography and HPLC, and was identified as heptelidic acid (koningic acid) by spectroscopic methods. This compound inhibited caspase-3 induction in U937 cells with an $IC_{50}$ value of 40 ${\mu}M$ after 8 h of etoposide treatment. Fluorescent dye staining with acridine orange and ethidium bromide showed that heptelidic acid inhibited apoptosis. Furthermore, it was found that DNA fragmentation and caspase-3 activation, the biological hallmarks of apoptosis, were inhibited by the compound in a dose-dependent manner, suggesting that heptelidic acid inhibits etoposide-induced apoptosis via downregulation of caspases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.168-171
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• 1998

Sesaminol in sesame seed was postulated to have antitumor activity. The present study was performed to characterize the role of crude sesaminol extracted from sesame seed (Sesame Crude Sesaminol; SCS) on inhibiting the in vitro growth of human leukemia HL-60 cells. SCS inhibited the growth of human leukemia HL 60 cells in culture and macromolecular synthesis in a dose and time dependent manner. The cytostatic range of SCS concentration was found to be 60 to 100 $\mu\textrm{g}$/ml. SCS concentration greater than 200 $\mu\textrm{g}$/mlwere cytocidal to HL-60 cells. When SCS concentraction was 6 $\mu\textrm{g}$/mland 50 $\mu\textrm{g}$/ml the synthesis of HL-60 cells was inhibited by 35% for DNA, 6% for RNA and 5% for protein and 83% for DNA, 76% for RNA and 60% for protein. Of specific interest was the irreversible effect of SCS in inhibiting DNA synthesis of HL-60 cells. This was evidenced from the fact that, even after washed with PBS three times, preincubated HL-60 cells still showed the inhibited DNA synthesis.