• IMMUNE NETWORK
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• v.6 no.4
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• pp.179-184
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• 2006

Background: Identification of antigen-specific T cells has yielded valuable information on pathologic process and the disease state. Assays for quantification of inflammatory cytokines or lytic-granule molecules have been generally used to evaluate antigen specific T cell response, however their applicability have been hampered due to the limited source of autologous antigen-presenting target cells (APC). Methods: K562, a leukemic cell line deficient of human leukocyte antigen (HLA), was transfected with a gene encoding HLA-A*02 (K562/ A*02) and its function as stimulator cells in inducing activation of HLA-matched T cells was evaluated by IFN-${\gamma}$ enzyme linked immunospot (ELISPOT) assay. Results: The stable transfectant K562/ A*02 pulsed with HLA- A*02 restricted peptide could specifically induce IFN-${\gamma}$ secretion by CD8+ T cells compared to no detectable secretion by CD4+ T cells. However, CD56+ NK cells secreted IFN-${\gamma}$ in both K562/ A*02 with peptide and without peptide. The number of IFN-${\gamma}$ secreted CD8+ T cells was increased according to the ratio of T cells to K562 and peptide concentration. Formalin-fixed K562/ A*02 showed similar antigen presenting function to live K562/ A*02. Moreover, K562/ A*02 could present antigenicpeptide to not only A*0201 restricted CD8+ T cells but also CD8+ T cells from A*0206 donor. Conclusion: These results suggest that K562/ A*02 could be generally used as target having specificity and negligible background for measuring CD8+ T cell responses and selective use of K562 with responsder matched HLA molecules on its surface as APC may circumvent the limitation of providing HLA-matched autologous target cells.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.166-177
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• 2006

Objectives : This study was performed to determine if Orostschys japonicus A. Berger has protective effects against CML in K562 cell lines. Materials and Methods : MTT assay, cell proliferation assay, Reverse transcription-polymerase reaction chain, RT-PCR, DNA fragmentation assay, Quantitative PCR were studied. Results : Orostschys japonicus A. Berger had no effects on Bax gene in K562 cell lines, but decreased Bcl-2 gene, and increased the Caspases-3 gene. This is indicate of induced apoptosis in K562 cell lines by Orostschys japonicus A. Berger. Conclusion : These results suggest that Orostschys japonicus A. Berger has effects on apatosis in K562 cell lines.

• IMMUNE NETWORK
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• v.7 no.2
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• pp.80-86
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• 2007

Background: CD40-activated B (CD40-B) cells might be an attractive source of autologous antigen-presenting cells (APCs) for immunotherapy due to the convenience to obtain from peripheral blood and expand in vitro. Moreover, CD40-B cells were found to be comparable with DCs in their capacity to raise antigen-specific CD8+ T cells. Here, we have established K562 cells expressing CD40L to expand CD40-activated B cells used for APCs. Methods: After activation of B cell by K562/CD40L, CD40-B cells were examined by counting B cell numbers. Surface expression of CD54, CD80, CD86 and HLA class II was measured by flow cytometry. The CD40-B cells were tested for its function as APC by mixed lymphocyte reactions (MLR) and by induction of T cell responses specific for pp65 peptide in vitro. Results: The expansion of B cells by K562/CD40L increased about 6-folds compared with anti-CD40 or K562. Furthermore, the expression of CD54, CD80, CD86 and HLA class II was up-regulated by K562/CD40L. B cells by K562/CD40L showed comparable antigen presentation activity with mature DCs as shown in MLR, INF-${\gamma}$ ELISPOT assay. Conclusion: These results suggest that K562/CD40L could be used to generate activated B cells as potent APCs which could be useful for cellular vaccination and adoptive immunotherapy.

• The Korean Journal of Nuclear Medicine
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• v.37 no.3
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• pp.178-189
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• 2003

Purpose: Cellular uptakes of $^{99m}Tc-sestamibi(MIBI)\;and\;\;^{99m}Tc-tetrofosmin$ into cancer cell lines expressing multidrug resistance(MDR) were investigated and compared. The effects of verapamil and cyclosporin A, well-known multidrug resistant reversing agents, on cellular uptakes of both tracers were also compared. Materials and Methods: Doxorubicin-resistant HCT15/CL02 human colorectal cell and doxorubicin-resistant K562(Adr) and vincristine-resistant K562(Vcr) human leukemic cells were studied. RT-PCR analysis was used for the detection of mdr1 mRNA expression. MDR-reversal effects with verapamil and cyclosporine A were evaluated at different drug concentrations after incubation with MIBI and tetrofosmin for 1, 15, 30, 45 and 60 min, using single-cell suspensions at $1{\times}10^6cells/ml$ incubated at $37^{\circ}C$. Radioactivity in supernatants and pellets were measured with gamma well counter. Results: The cellular uptakes of MIBI and tetrofosmin in K562(Adr) and K562(Vcr) were lower than those of parental K562 cell. In HCT15/CL02 cells and K562(Adr) cells, there were no significant difference in cellular uptakes of both tracers, but cellular uptake of MIBI was higher than that of tetrofosmin in K562(Vcr) cells. Coincubation with verapamil resulted in a increase In cellular uptakes of MIBI and tetrofosmin. Verapamil increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 11.9- and 6.8-fold, by K562(Adr) cell by 14.3- and 8-fold and by K562(Vcr) cell by 7- and 5.7-fold in maximum, respectively. Cyciosporin A increased cellular uptakes of MIBI and tetrofosmin by HCT15/CL02 cell by 10- and 2.4-fold, by K562(Adr) cell by 44- and 13-fold and by K562(Vcr) cell by 18.8- and 11.8-fold in maximum, respectively Conclusion: Taking together, MIBI and tetrofosmin are considered as suitable radiopharmaceuticals for defecting multidrug resistance. However, MIBI seems to be a better tracer than tetrofosmin for evaluating MDR reversal effect of the modulators. Since cellular uptakes of both tracers might differ in different cell types, further experiments regarding differences in cellular uptakes between cell types should be explored.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.2
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• pp.68-75
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• 2007

After reports on regression of cancer in humans and animals infected with microbial pathogens date back more than 100 years, much effort has been spent over the years in developing a wild type or attenuated bacterial and purified bacterial proteins for the treatment of cancer. Pseudomonas aeruginosa exotoxin A (ETA) is known to inhibit cell growth and trigger significant cell death in various cancer cells. Although ETA induces apoptosis of cancer cells, its exact mechanism of action is not known yet. Four different assays were performed in this study: morphological assessment of apoptotic cells, cell cytotoxity, annexin-V binding assay, and cell cycle analysis. The proliferation and survival of the K-562 cells treated with ETA were decreased in a dose dependent manner. In addition, the apoptotic body of K-562 cells was induced by ETA treatment in a dose dependent manner. The ETA-induced apoptosis was confirmed by annexin-V binding assay. Flow cytometric analysis was examined to ascertain whether ETA could arrest the cell cycle at the sub-G1 phase. Our results suggest that P. aeruginosa ETA inhibits cell growth and induces apoptosis in human leukemia K-562 cells.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.11
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• pp.4857-4861
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• 2016

Background: Imatinib mesylate, a tyrosine kinase inhibitor specifically targeting the BCR/ABL fusion protein, induces hematological remission in patients with chronic myeloid leukemia (CML). However, the majority of CML patients treated with imatinib develop resistance with prolonged therapy. Dendrophthoe pentandra (L.) Miq. is a Malaysian mistletoe species that has been used as a traditional treatment for several ailments such as smallpox, ulcers, and cancers. Methods: We developed a resistant cell line (designated as K562R) by long-term co-culture of a BCR/ABL positive CML cell line, K562, with imatinib mesylate. We then investigated the anti-proliferative effects of D. pentandra methanol extract on parental K562 and resistant K562R cells. Trypan blue exclusion assays were performed to determine the IC50 concentration; apoptosis and cell cycle analysis were conducted by flow cytometry. Results: D. pentandra extract had greater anti-proliferative effects towards K562R ($IC50=192{\mu}g/mL$) compared to K562 ($500{\mu}g/mL$) cells. Upon treatment with D. pentandra extract at the IC50. concentration: K562 but not K562R demonstrated increase in apoptosis and cell cycle arrest in the G2/M phase. Conclusion: D. pentandra methanol extract exerts potent anti-proliferative effect on BCR/ABL positive K562 cells.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.51-57
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• 1989

This study was performed to investigate the toxicity of ochratoxin A (OA) to the chromosomes of $K_{562}$ tumor cell-line in vitro. The results of this experiment were as follows: 1) Chromosomes of $K_{562}$tumor cell-line resulted in pseudotriploidy on the control group. Chromosomes of $K_{562}$ tumor cell-line treated with OA resulted in heteroploidy compared with the control group. The mean number of chromosomes in the karyotype of the control group (60) were 7 in the A group, 5 in the B group, 20 in the C+X group, 7 in the D group, 9 in the E group, 6 in the F group, and 6 in the G+Y group respectively. The number of chromosomes were increased as follows: Treating with $0.7{\mu}M$ OA, the number of chromosomes were increased one in E and F group, two in G+Y group compared with control group. In treated with $1.5{\mu}M$ OA, the increasing number of chromosome was one in E and F group. In treated with $3{\mu}M$ OA, E and F group was increased one and G+Y group were increased two chromosomes compared with control group. But in treated with $6{\mu}M$ OA, the number of chromosome in G+Y group was decreased one. 2) $K_{562}$ tumor cell line treated with OA showed Philadelphia-Chromosome in the long arm of the G group karyotype chromosome. The rate of chromosome aberration in $K_{562}$ tumor cell-line treated with OA was 77% in $0.7{\mu}M$ OA group, 71% in $1.5{\mu}M$ OA group, 82% in $3{\mu}M$ OA group and 94% in $6{\mu}M$ OA group respectively. The rate of chromosome aberration of $K_{562}$ tumor cell-line treated with OA was high in the high dose level of OA, and chromosome aberration of $K_{562}$ tumor cell-line treated with OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype. As a result of this study, the toxicity of OA showed deletion, minute, dicentric-chromosome and translocation in the long arm of the C-group karyotype, and then, the toxicity of OA resulted in the damage to RNA and protein synthesis in $K_{562}$ tumor cell-line, and the C-group karyotype of $K_{562}$ tumor cell-line was target of the toxicity of OA.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7501-7508
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• 2013

Background: Chronic myeloid leukemia (CML) is a myeloproliferative disorder of hematopoietic stem cell scarrying the Philadelphia (Ph) chromosome and an oncogenic BCR-ABL1 fusion gene. The tyrosine kinase inhibitor (TKI) of BCR-ABL1 kinase is a treatment of choice for control of CML. Objective: Recent studies have demonstrated that miRNAs within exosomes from cancer cells play crucial roles in initiation and progression. This study was performed to assess miRNAs within exosomes of K562 cells. Methods: miRNA microarray analysis of K562 cells and K562 cell-derived exosomes was conducted with the 6th generation miRCURYTM LNA Array (v.16.0). Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were also carried out. GO terms and signaling pathways were categorized into 66 classes (including homophilic cell adhesion, negative regulation of apoptotic process, cell adhesion) and 26 signaling pathways (such as Wnt). Results: In exosomes, 49 miRNAs were up regulated as compared to K562 cells, and two of them were further confirmed by quantitative real-time PCR. There are differentially expressed miRNAs between K562 cell derived-exosomes and K562 cells. Conclusion: Selectively expressed miRNAs in exosomes may promote the development of CML via effects on interactions (e.g. adhesion) of CML cells with their microenvironment.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9131-9136
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• 2014

ELDF15, homologous with AT2 receptor-interaction protein 1 (ATIP1), may play an important role in cell differentiation, proliferation, and carcinogenesis. We aimed to understand the biological function of ELDF15 via construction and transfection of a recombinant expression vector containing antisense ELDF15. Recombinant expression vectors were successfully constructed and transfected into K562 cells. A stable transfectant, known as pXJ41-asELDF15, stably produced antisense ELDF15. Compared with K562 and K562-zeo cells, K562-pXJ41-asELDF15 cells showed inhibition of cell proliferation. RT-PCR analysis showed that the expression and protein level of ELDF15 decreased significantly in K562 cells transfected with pXJ41-asELDF15. Expression of hemoglobin increased in K562 cells transfected with pXJ41-asELDF15 by benzidine staining. increases NBT reduction activity in K562 cells transfected with pXJ41-asELDF15.Colony forming efficiency in two-layer soft agar was clearly inhibited as assessed by electron microscopy. These results suggest that ELDF15 plays a potential role in cell differentiation, proliferation and carcinogenesis.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.12-20
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• 1996

A multipotential hematopojetic cell line, 1(562 cell, was differentiated into megakaryocyte by a chemical inducer, PMA, with an enhanced expression of gpIlla accompaning with a distinct morphological change. On the other hand, 1(562 cells were differentiated into erythrocytes by other chemical inducers, DMSO or butyrate, with a concomitant increase in hemoglobin accumulation. An antigen of apparent molecular weight of 61 kDa was identified on the surface of 1(562 cells by using monoclonal antibody raised against 1(562 cells. The antigen was considered to be a glycoprotein molecule rich in sialic acids and the epitope of antigen was sensitive to neuraminidase digestion or peroxidase oxidation, but resistant to heat treatment. The 61 kDa surface antigen was increased or decreased in its expression along differentiation of 1(562 cells into megakaryocytes or erythrocytes, respedively.