• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.705-709
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• 1998

In the course of screening for the substances suppressing bleb formation of K562 cell induced by phorbol 12, 13-dibutyrate (PDBu), an inhibitor, chaetoglobosin A (CgA) was isolated from a cultured broth of unidentified fungus. CgA showed a strong inhibitory activity with the $IC_{50}$ value of 60 pM against bleb formation on K562 cells induced by PDBu, but it did not inhibit the activity of protein kinase C (PKC) in vitro. The inhibitory activity of CgA might be due to the modulation of actin filaments on the cell membrane. CgA exhibited strong cytotoxicity against various human cancer cell lines.

• Biomolecules & Therapeutics
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• v.24 no.2
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• pp.147-155
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• 2016

Chaetominine is a quinazoline alkaloid originating from the endophytic fungus Aspergillus fumigatus CY018. In this study, we showed evidence that chaetominine has cytotoxic and apoptotic effects on human leukemia K562 cells and investigated the pathway involved in chaetominine-induced apoptosis in detail. Chaetominine inhibited K562 cell growth, with an $IC_{50}$ value of 35 nM, but showed little inhibitory effect on the growth of human peripheral blood mononuclear cells. The high apoptosis rates, morphological apoptotic features, and DNA fragmentation caused by chaetominine indicated that the cytotoxicity was partially caused by its pro-apoptotic effect. Under chaetominine treatment, the Bax/Bcl-2 ratio was upregulated (from 0.3 to 8), which was followed by a decrease in mitochondrial membrane potential, release of cytochrome c from mitochondria into the cytosol, and stimulation of Apaf-1. Furthermore, activation of caspase-9 and caspase-3, which are the main executers of the apoptotic process, was observed. These results demonstrated that chaetominine induced cell apoptosis via the mitochondrial pathway. Chaetominine inhibited K562 cell growth and induced apoptotic cell death through the intrinsic pathway, which suggests that chaetominine might be a promising therapeutic for leukemia.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.913-921
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• 2005

In this study, we investigated gene expression patterns induced by Ailanthus altissima extract and compared it with Gleevec, a well-known anti-leukemia drug, in K562 chromic leukemia cells. Ailanthus altissima extract(100 ug/ml) and Gleevec(50 ug/ml) were treated to cells for 1h, 2h, 4h, and 16h and total RNA was extracted. Gene expressions were evaluated using cDMA microarray, in which 24,000 genes were spotted. Hierarchical clustering analysis showed that expression of genes included in two clusters were increased or decreased time dependently by both Ailanthus altissima extract and Gleevec. Genes included in another cluster were induced by Ailanthus altissima extract but not by Gleevec. In biological process analysis, expression of genes involved in apoptosis, growth arrest and DNA-damage were increased, but genes stimulating cell cycle were decreased. This study provides comprehensive comparison of the patterns of gene expression changes induced by Ailanthus altissima extract and Gleevec in K-562 leukemia cells.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.490-496
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• 2017

Imatinib resistance has become a major clinical problem for chronic myeloid leukemia. The aim of the present study was to investigate the involvement of MEG3, a lncRNA, in imatinib resistance and demonstrate its underlying mechanisms. RNAs were extracted from CML patients' peripheral blood cells and human leukemic K562 cells, and the expression of MEG3 was measured by RT-qPCR. Cell proliferation and cell apoptosis were evaluated. Western blotting was used to measure the protein expression of several multidrug resistant transporters. Luciferase reporter assay was performed to determine the binding between MEG3 and miR-21. Our results showed that MEG3 was significantly decreased in imatinib-resistant CML patients and imatinib-resistant K562 cells. Overexpression of MEG3 in imatinib-resistant K562 cells markedly decreased cell proliferation, increased cell apoptosis, reversed imatinib resistance, and reduced the expression of MRP1, MDR1, and ABCG2. Interestingly, MEG3 binds to miR-21. MEG3 and miR-21 were negatively correlated in CML patients. In addition, miR-21 mimics reversed the phenotype of MEG3-overexpression in imatinib-resistant K562 cells. Taken together, MEG3 is involved in imatinib resistance in CML and possibly contributes to imatinib resistance through regulating miR-21, and subsequent cell proliferation, apoptosis and expression of multidrug resistant transporters.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7095-7100
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• 2013

Histone deacetylase (HDAC) inhibitors of cyclic peptide have been proved to be the most complex but the most stable and relative efficient inhibitors because of their large cap region. In this paper, a series of studies were carried out to evaluate the efficacy of synthetic bicyclic tetrapeptide inhibitors 1-5 containing hydroxamic acid referring molecular docking, anti-proliferation, morphology and apoptosis. Docking analysis, together with enzyme inhibitory results, verified the selective capability of inhibitor 4 to HDAC4, which might closely related to haematological tumorigenesis, with Phe227, Asp115, Pro32, His198 and Ser114 participating into hydrophobic interactions and Van der Waals force which was familiar with former study. Moreover, inhibitor 4 inhibited K562 cell line at the $IC_{50}$ value of 1.22 ${\mu}M$ which was 51-67 times more efficient than that for U937 and HL60 cell lines. Inhibitor 4 exhibited the cell cycle-arrested capability to leukemia at S phase or G2/M phase as well as apoptosis-induced ability in different degrees. Finally, we considered that bicyclic tetrapeptide inhibitors were promising inhibitors used in cancer treatment and inhibitor 4 could prevent K562 cell line well from proliferation, arrest cell cycle and induce K562 towards apoptosis to achieve the goals of reversing cancer cells which could become a potential leukemia therapeutic agent in the future.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.7-15
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• 2015

Purpose: The purpose of this study is to investigate secondary infections within the households of newly diagnosed tuberculosis patients. Methods: We collected data on household infections of tuberculosis patients by retrospective review of medical records and telephone surveys. Results: Out of 321 newly diagnosed tuberculosis cases, a total of 253 patients who received telephone surveys were enrolled in this study. Less than 50% of the patients had household contacts screened for tuberculosis infection, and most of the patients were not aware of the necessity of testing. Out of 562 household contacts, there were 8 cases of secondary tuberculosis (1.4%, 8/562) in 7 households. There were 15 cases of latent infection (2.7%, 15/562) in 13 households. Out of 110 child and adolescent household contacts, there were no cases of secondary tuberculosis, and there were 8 cases of latent infection (7.3%) in 7 households, which was 20.5% among child and adolescent contacts screened for tuberculosis infection. In 3 of the cases (13.0%) that had secondary tuberculosis or latent infection in their households, the source of infection was extrapulmonary tuberculosis. There was no correlation between the frequency of household infections and the presence of pulmonary cavities, sputum AFB smear results, and microbiologically confirmed results. Conclusions: For effective investigation of tuberculosis contacts, it is necessary to raise general awareness on the necessity of investigating household contacts, and there should also be a continued assessment on tuberculosis contact investigation since government-supported programs.

• Toxicological Research
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• v.27 no.1
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• pp.43-48
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• 2011

Even though exposure to benzene has been linked to a variety of cancers including leukemia, the detailed molecular mechanisms relevant to benzene-induced carcinogenesis remain to be clearly elucidated. In this study, we evaluated the effects of benzene on differential gene expression in a leukemia cell line. The K562 leukemia cell line used in this study was cultured for 3 h with 10 mM benzene and RNA was extracted. To analyze the gene expression profiles, a 41,000 human whole genome chip was employed for cDNA microarray analysis. We initially identified 6,562 genes whose expression was altered by benzene treatment. Among these, 3,395 genes were upregulated and 3,167 genes were downregulated by more than 2-fold, respectively. The results of functional classification showed that the identified genes were involved in biological pathways including transcription, cell proliferation, the cell cycle, and apoptosis. These gene expression profiles should provide us with further insights into the molecular mechanisms underlying benzene-induced carcinogenesis, including leukemia.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9915-9919
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• 2014

Lamellarin D (LamD) is a marine alkaloid with a pronounced cytotoxicity against a large panel of cancer cells, affecting cell growth and inducing apoptosis. However, the molecular mechanisms of action of this compound are poorly understood. In this study, the anticancer efficacy of LamD was investigated in human leukemia K562 cells. The results showed suppressed cell proliferation and induction of G0/G1-phase arrest,while expression of CDK1, and activity of smad3 and smad5 were reduced, but that of p27, p53 and STGC3 was increased. LamD induced cell apoptosis through activation of caspases-8/-3, inhibition of survivin and Bcl-2, suggesting that this compound may also act through a caspase-independent pathway. Moreover, LamD inhibited the secretion of TGF-${\beta}$, IL-$1{\beta}$, IL-6, IL-8 and other inflammatory cytokines and the transcriptional activity of transcription factor NF-${\kappa}B$ in human leukemia K562 cells.Taken together, our results suggest that LamD-mediated inhibition of leukemia cell proliferation may be related to the induction of apoptosis and the regulation of cell cycle, tumor-related gene expression and cytokine expression, which may provide a new way of thinking for the treatment leukemia.

• BMB Reports
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• v.40 no.6
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• pp.944-951
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• 2007

3-Hydrogenkwadaphnin (3-HK) is a daphnane-type diterpene ester isolated from Dendrostellera lessertii (Thymelaeaceae) with high differentiation and apoptotic potency in leukemic cells without any measurable adverse effects on normal cells (Moosavi et al., 2005b). In this study, we report that 3-HK (12 nM) has the ability to cease proliferation, induce differentiation and apoptosis in chronic myelogenous leukemia (CML) K562 cell line. The treated cells lost erythroid properties and differentiated along the megakaryocytic lineage based on the morphological features apparent after Wright-Giemsa staining, DNA content analysis and the expression of cell surface marker glycoprotein IIb as analyzed by flow cytometry. Moreover, using Hoechst 33258 and Annexin V double staining indicated the occurrence of apoptosis among the treated cells. On the other hand, restoration of the depleted GTP pool size by exogenous addition of guanosine ($50{\mu}M$) reduced the effect of the drug regarding the extent of differentiation while no further enhancement of 3-HK effect was obtained by addition of exogenous hypoxanthine ($100{\mu}M$). These interesting results necessitate further investigation regarding the mechanism of action of this unique anti-leukemic agent.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6423-6428
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• 2015

The present study was designed to evaluate in vitro anti-proliferative potential of extracts from four Indian medicinal plants, namely Anogeissus latifolia, Terminalia bellerica, Acacia catechu and Moringa oleiferna. Their cytotoxicity was tested in nine human cancer cell lines, including cancers of lung (A549), prostate (PC-3), breast (T47D and MCF-7), colon (HCT-16 and Colo-205) and leukemia (THP-1, HL-60 and K562) by using SRB and MTT assays. The findings showed that the selected plant extracts inhibited the cell proliferation of nine human cancer cell lines in a concentration dependent manner. The extracts inhibited cell viability of leukemia HL-60 and K562 cells by blocking G0/G1 phase of the cell cycle. Interestingly, A. catechu extract at $100{\mu}g/mL$ induced G2/M arrest in K562 cells. DNA fragmentation analysis displayed the appearance of a smear pattern of cell necrosis upon agarose gel electrophoresis after incubation of HL-60 cells with these extracts for 24h.