• Biomolecules & Therapeutics
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• 제12권2호
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• pp.85-91
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• 2004

In all attempt to elucidate the role of apoptosis in drug resistance, cisplatin-resistant human chronic myelogenous leukemia (CML) K562 cells (K562/CDDP) were established and compared with drug sensitive parent cells (K562) in the induction of apoptosis. K562/CDDP cells were 5-fold more resistant to cisplatin compared to K562 cells. In addition, K562/CDDP cells were significantly more resistant to apoptois as judged by DNA fragmentation and DAPI staining. K562/CDDP cells exhibited decreased proleolytic activity of caspase-3 and this was further demonstrated by decreased cleavage of its substrate poly (ADP-ribose) polymerase (PARR- Western blot analysis showed that K562/CDDP cells had longer sustained levels of BCL-$X_L$ whereas no difference was noted in the level of Bcl-2. the translocation of Bax to mitochondria was significantly delayed in K562/CDDP cells. These results suggest that the reduced translocation of Bax and the sustained expression of BCL-$X_L$ may cause resistance to apoptosis through prevention of mitochondria release of cytochrome c, which subsequently induces reduction of caspase-3 activity and that this response is partly responsible for the acquired resistance to cisplatin ill K562 cells.

• IMMUNE NETWORK
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• 제6권4호
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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.

• 한국동물학회지
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• 제39권1호
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• pp.12-20
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• 1996

K562 적혈구암 세포는 phorbol 12-myristate 13-acetate(PMA)에 의해서 대핵세포로 분화되고 gpIlla의 증가, megakaryocyte와 유사한 형태학적 변화로 특징지워진다. 또한 K562 세포는 dimethy1 sulfoxide(DMSO)나 butyrate와 같은 화학적 유도원에 의해 적혈구로 분화가 유도되고 동시에 헤모글로빈이 축척된다. 본 연구에서는 K562 세포에 대한 단일클론 항체를 생성하고 이를 이용하고 61 KDa의 표면항원을 동정하였다. 단클론항체 EK-2에 의해 인지되는 61 KDa의 표면항원은 sialic acide가 풍부해 당단백질로 사료되고, 그 epitope는 neuraminidase 절단과 peroxidase oxidation에 민감하며, 열처리에는 안정하다. K562 세포의 대핵세포로 분화시에는 61 KDa 표면항원의 발현은 증가하며, 적혈구로 분회시에는 그 발현이 감소한다. EK-2 단클론항체는 조혈세포의 분화 및 암화과정의 분자적 수준을 연구하기 위한 면역학적 probe로 이용 가능할 것으로 기대된다.

• IMMUNE NETWORK
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• 제7권2호
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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.

• Asian Pacific Journal of Cancer Prevention
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• 제17권11호
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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.

• 대한핵의학회지
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• 제37권3호
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• pp.178-189
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• 2003

목적: 다약제내성이 유발된 암세포에서 $^{99m}Tc-sestamibi$와 $^{99m}Tc-tetrofosmin$의 암세포 내 섭취정도를 비교하고 다약제내성 극복제로 잘 알려진 verapamil 과 cyclosporin A 처리에 의한 두 방사성 의약품의 암세포 내 섭취정도를 비교해 보았다. 재료 및 방법: Doxorubicin으로 다약제내성이 유발된 HCT15/CL02 대장암 세포와 doxorubicin과 vincristine으로 다약제내성을 유발시킨 K562(Adr)과 K562(Vcr) 백혈병 세포를 사용하였다. 다약제내성의 발현은 RT-PCR로 증명하였으며, verapamil은 1, 10, 50, 100, 200 ${\mu}M$의 농도로, cyclosporin A는 0.1, 10, 50, 100 ${\mu}M$의 농도로 각각 사용하였다. MIBI와 tetrofosmin의 암세포내 섭취는 $37^{\circ}C$에서 $1{\times}10^{6}cells/ml$ 농도의 단일세포 부유상태에서 1, 15, 30, 45, 60분 간격으로 배양하여 각 시간대별로 상층액과 침전물을 분리하여 각각의 방사능을 감마 계수기로 측정하였다. 결과: 다약제내성이 발현된 암세포에서는 모세포에 비하여 MIBI와 tetrofosmin의 섭취가 감소되었다. 두 방사성약품의 섭취정도는 HCT15/CL02세포와 K562(Adr)세포에서는 유의한 차이가 없었으나, K562(Vcr)세포에서는 MIBI가 tetrofosmin보다 다소 높았다. Verapamil과 cyclosporin A를 처리하였을 때 MIBI와 tetrofosmin의 섭취율은 기저치보다 모두 증가하였고, verapamil 에 의한 MIBI와 tetrofosmin의 섭취율(30분)을 기저치(30분)와 비교해 본 결과 HCT15/CL02 세포에서($100{\mu}M$)는 각각 11.9배와 6.8배, K562(Adr) 세포에서($50{\mu}M$)는 각각 14.3배와 8배, K562(Vcr) 세포에서($10{\mu}M$)는 각각 7배와 5.7배 증가하였다. Cyclosporin A에 의한 MIBI와 tetrofosmin의 섭취율(30분)을 기저치(30분)와 비교해 본 결과 HCT15/CL02세포에서($50{\mu}M$)는 각각 10배와 2.4배, K562(Adr)세포에서($50{\mu}M$)는 각각 44배와 13배, K562(Vcr)세포에서($10{\mu}M$)는 각각 18.8배와 11.8배 증가하여, MIBI의 섭취율이 tetrofosmin보다 1.2배에서 4배정도 높게 나타났다. 결론: 이러한 결과로 보아 MIBI와 tetrofosmin은 다약제내성의 발현을 평가할 수 있는 방사성의약품으로 판단되며, 다약제내성 극복제의 효능평가에는 MIBI가 tetrofosmin보다 더 우수할 것으로 사료되나, 세포추에 따른 차이가 있을 수 있으므로 보다 많은 세포주에서의 추가적인 연구가 필요할 것이다.

• 대한한방내과학회지
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• 제27권1호
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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.

• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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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.

• Journal of Ginseng Research
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• 제13권1호
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• pp.24-29
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• 1989

본 실험에서는 대식세포에 의한 K562 종양세포의 치사에 미치는 인삼 분획물들의 영향을 알아보기 위하여 실험한 결과 다음과 같은 결론을 얻었다. 1. LPS만을 처리하여 주어 종양세포의 치사 활성을 유도한 대식세포보다도 LPS 와 saponin을 복합처리하여준 대식세포가 K562 종양세포에 대하여 더 높은 종양 치사 활성을 나타내었다. 이러한 결과는 인삼 분획물 즉, total, diol, triol saponin 모두 같은 양상을 나타내었다. 2. 대식세포없이 배양엑에 인삼 saponin 만을 처리하여 주었을 경우, 인삼 saponin 이 K562 종양세포에 대한 치사작용을 나타내지 않았다. 3. 이러한 결과로 인삼 saponin이 대식세포를 통하여 K562 세포 치사 활성을 증가시킨다는 것을 확인하였다.

• 한국동물학회지
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• 제39권1호
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• pp.47-53
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• 1996

K562 백혈구암 세포의 phorbol 12-myristate 13-acetate(PMA)에 의한 대핵세포로의 분화과정에서 heat shock proteins(HSPs)와 glucose-regulated proteins(GRPs)의 발현을 조사하였다. PMA에 의한 K562 세포의 분화 특징은 세포성장의 억제, 형태학적 변화, gpllIa의 발현 증가, c-myc 발현의 감소 등으로 나타난다. PMA에 의한 대핵세포 분화과정에서, HSP90A, HSP90B 그리고 HSP28 mRNA와 단백질 합성은 현저히 감소하는 반면, GRP78/BiP와 GRP94의 mRNA 합성은 증가하였다. 한편 HSP7OA와 HSP7OB의 mRNA 합성은 감소하였지만, HSP70 단백질의 합성은 변함이 없었다. 이러한 결과는 HSPs와 GRPs가 K562 세포의 증식 또는 대핵세포 분화 과정에서 특이한 역할을 할 것임을 시사하고 있다.