• BMB Reports
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• 제55권3호
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• pp.142-147
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• 2022

Human pluripotent stem cells (PSCs) have been utilized as a promising source in regenerative medicine. However, the risk of teratoma formation that comes with residual undifferentiated PSCs in differentiated cell populations is most concerning in the clinical use of PSC derivatives. Here, we report that a monoclonal antibody (mAb) targeting PSCs could distinguish undifferentiated PSCs, with potential teratoma-forming activity, from differentiated PSC progeny. A panel of hybridomas generated from mouse immunization with H9 human embryonic stem cells (hESCs) was screened for ESC-specific binding using flow cytometry. A novel mAb, K312, was selected considering its high stem cell-binding activity, and this mAb could bind to several human induced pluripotent stem cells and PSC lines. Cell-binding activity of K312 was markedly decreased as hESCs were differentiated into embryoid bodies or by retinoic acid treatment. In addition, a cell population negatively isolated from undifferentiated or differentiated H9 hESCs via K312 targeting showed a significantly reduced expression of pluripotency markers, including Oct4 and Nanog. Furthermore, K312-based depletion of pluripotent cells from differentiated PSC progeny completely prevented teratoma formation. Therefore, our findings suggest that K312 is utilizable in improving stem cell transplantation safety by specifically distinguishing residual undifferentiated PSCs.

• 한국발생생물학회지:발생과생식
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• 제11권2호
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• pp.67-77
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• 2007

최근 제 1형 당뇨병을 치료하기 위하여 인슐린-분비성 세포를 이식하는 세포대체요법이 새로운 치료법으로서 주목받고 있다. 그럼에도 불구하고 췌장세포 이식술은 이식원의 절대적인 부족으로 인해 광범위한 시행이 이루어지지 못하고 있는 실정이다. 무한증식과 전분화능을 보유하는 배아줄기세포는 이식할 $\beta$-세포의 부족을 해결할 수 있는 잠재적 세포공급원이 될 수 있을 것으로 기대된다. 본 종설에서는 인간배아줄기세포로부터 췌장 $\beta$-세포로의 유도분화방법에 관한 최근 동향을 살펴보고, 당뇨병 치료에 세포 이식술을 적용함에 있어 고려해야할 문제점 및 극복방안들을 소개하고자 한다.

• 한국동물생명공학회지
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• 제37권2호
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• pp.67-79
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• 2022

Currently, there is no treatment to reverse or cure heart failure caused by ischemic heart disease and myocardial infarction despite the remarkable advances in modern medicine. In addition, there is a lack of evidence regarding the existence of stem cells involved in the proliferation and regeneration of cardiomyocytes in adult hearts. As an alternative solution to overcome this problem, protocols for differentiating human pluripotent stem cell (hPSC) into cardiomyocyte have been established, which further led to the development of cell therapy in major leading countries in this field. Recently, clinical studies have confirmed the safety of hPSC-derived cardiac progenitor cells (CPCs). Although several institutions have shown progress in their research on cell therapy using hPSC-derived cardiomyocytes, the functions of cardiomyocytes used for transplantation remain to be those of immature cardiomyocytes, which poses a risk of graft-induced arrhythmias in the early stage of transplantation. Over the last decade, research aimed at achieving maturation of immature cardiomyocytes, showing same characteristics as those of mature cardiomyocytes, has been actively conducted using various approaches at leading research institutes worldwide. However, challenges remain in technological development for effective generation of mature cardiomyocytes with the same properties as those present in the adult hearts. Therefore, in this review, we provide an overview of the technological development status for maturation methods of hPSC-derived cardiomyocytes and present a direction for future development of maturation techniques.

• BMB Reports
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• 제48권12호
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• pp.668-676
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• 2015

Pluripotent stem cells only exist in a narrow window during early embryonic development, whereas multipotent stem cells are abundant throughout embryonic development and are retainedin various adult tissues and organs. While pluripotent stem cell lines have been established from several species, including mouse, rat, and human, it is still challenging to establish stable multipotent stem cell lines from embryonic or adult tissues. Based on current knowledge, we anticipate that by manipulating extrinsic and intrinsic signaling pathways, most if not all types of stem cells can be maintained in a long-term culture. In this article, we summarize current culture conditions established for the long-term maintenance of authentic pluripotent and multipotent stem cells and the signaling pathways involved. We also discuss the general principles of stem cell maintenance and propose several strategies on the establishment of novel stem cell lines through manipulation of signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6549-6556
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• 2013

Leukemia stem cells (LSCs) play important roles in leukemia initiation, progression and relapse, and thus represent a critical target for therapeutic intervention. Hence, it is extremely urgent to explore new therapeutic strategies directly targeting LSCs for acute myelogenous leukemia (AML) therapy. We show here that Angelica sinensis polysaccharide (ASP), a major active component in Dong quai (Chinese Angelica sinensis), effectively inhibited human AML $CD34^+CD38^-$ cell proliferation in vitro culture in a dose-dependent manner while sparing normal hematopoietic stem and progenitor cells at physiologically achievable concentrations. Furthermore, ASP exerted cytotoxic effects on AML K562 cells, especially LSC-enriched $CD34^+CD38^-$ cells. Colony formation assays further showed that ASP significantly suppressed the formation of colonies derived from AML $CD34^+CD38^-$ cells but not those from normal $CD34^+CD38^-$ cells. Examination of the underlying mechanisms revealed that ASP induced $CD34^+CD38^-$ cell senescence, which was strongly associated with a series of characteristic events, including up-regulation of p53, p16, p21, and Rb genes and changes of related cell cycle regulation proteins P16, P21, cyclin E and CDK4, telomere end attrition as well as repression of telomerase activity. On the basis of these findings, we propose that ASP represents a potentially important agent for leukemia stem cell-targeted therapy.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권2호
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• pp.133-141
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• 2008

Stem cells have self-renewal capacity, long-term viability, and multiline age potential. Adult bone marrow contains mesenchymal stem cells. Bone marrow-derived mesenchymal stem cells (BMSCs) are progenitors of skeletal tissue components and can differentiate into adipocytes, chondrocytes, osteoblasts, and myoblasts in vitro and undergo differentiation in vivo. However, the clinical use of BMSCs has presented problems, including pain, morbidity, and low cell number upon harvest. Recent studies have identified a putative stem cell population within the adipose tissue. Human adipose tissue contains pluripotent stem cells simillar to bone marrow-derived stem cells that can differentiate toward the osteogenic, adipogenic, myogenic, and chondrogenic lineages. Human adipose tissue-derived stem cells (ATSCs) could be proposed as an alternative source of adult bone marrow stem cells, and could be obtained in large quantities, under local anesthesia, with minimal discomfort. Human adipose tissue obtained by liposuction was processed to obtain ATSCs. In this study, we compared the osteogenic differentiation of ATSCs in a specific osteogenic induction medium with that in a non-osteogenic medium. ATSCs were incubated in an osteogenic medium for 28 days to induce osteogenesis respectively. Osteogenic differentiation was assessed by von Kossa and alkaline phosphatase staining. Expression of osteocyte specific bone sialoprotein, osteocalcin, collagen type I and alkaline phosphatase, bone morphogenic protein 2, bone morphogenic protein 6 was confirmed by RT-PCR. ATSCs incubated in the osteogenic medium were stained positively for von Kossa and alkaline phosphatase staining. Expression of osteocyte specific genes was also detected. Since this cell population can be easily identified through fluorescence microscopy, it may be an ideal source of ATSCs for further experiments on stem cell biology and tissue engineering. The present results show that ADSCs have an ability to differentiate into osteoblasts. In the present study, we extend this approach to characterize adipose tissue-derived stem cells.

• 분석과학
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• 제31권6호
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• pp.232-239
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• 2018

Human breast milk (HBM) provides neonates with indispensable nutrition. The present study evaluated the anti-cancer activity of diluted and pasteurized early HBM (< 6 weeks' lactation) on human breast cancer cell lines. The cell lines MCF7 and MDA-MB231 were exposed to 1 % HBM from the 1st, 3rd, and 6th weeks of lactation and exhibited reduced proliferation rates. As controls, breast cell lines (293T and MCF-10A), breast cancer cell lines (MCF-7 and MDA-MB-231), and $CD133^{hi}CXCR4^{hi}ALDH1^{hi}$ patient-derived human cancer stem-like cells (KU-CSLCs) were treated with prominent milk proteins ${\beta}$-casein, ${\kappa}$-casein, and lactoferrin at varying doses (10, 50, and $100{\mu}g$) for 24 or 48 hrs. The impact of these proteins on cell proliferation was investigated. Breast cancer cell lines treated with ${\kappa}$-casein and lactoferrin exhibited significantly reduced viability, in both a dose- and time-dependent manner. Interestingly, ${\kappa}$-casein selectively impacted only cancer (but not normal breast) cell lines, particularly the more malignant cell line. However, ${\beta}$-casein-exposed human breast cancer cell lines exhibited a significantly higher proliferation rate. Thus, ${\kappa}$-casein and lactoferrin appear to exert selective anti-cancer activities. Further studies are warranted to determine the mechanisms underlying ${\kappa}$-casein- and lactoferrin-mediated cancer cell-selective cytotoxic effects.

• 대한의생명과학회지
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• 제13권4호
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• pp.273-278
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• 2007

Stem cells have been the subject of increasing scientific interest because of their utility in numerous biomedical applications. Stem cells are capable of renewing themselves; that is, they can be continuously cultured in an undifferentiated state, giving rise to more specialized cells of the human body. Therefore, stem cells are an important new tools for developing unique, in vitro model systems to test drugs and chemicals and a potential to predict or anticipate toxicity in humans. In the present study, in vitro cultured F3 immortalized human neural stem cell line and in vivo adult Sprague Dawley rats was used to evaluate the cytotoxicity of anticancer drug paclitaxel. In vitro apoptotic activity of paclitaxel was evaluated in F3 cell line by a MTT assay and DAPI test. The cell death was induced with the treatment of 20 nM paclitaxel and chromatin degradation was detected by DAPI staining, which was analyzed by fluorescent microscope. In vivo studies, we also observed nestin immunoreactivity on subventricular zone, which is stem cell rich region in the adult brain of the SD rat. Immunofluorescent staining result shows that pixel intensities of nestin were decreased in a dose dependent manner. These results suggest that paclitaxel is able to induce cytotoxic activity both in F3 neural stem cell line and neural stem cell in SD rat brain.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.95-103
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• 2019

대표적인 치주질환인 치주염은 출혈, 통증 및 치아 손실을 초래하며, 산화적 스트레스는 치주염의 주요 원인으로 알려져 있다. 본 연구는 지방조직 유래 무막줄기세포추출물의 $H_2O_2$ 유도 산화적 손상에 대한 치주염 보호 효과를 확인하고자, 치주인대 섬유모세포(human periodontal ligament fibroblasts; HPLF)를 이용하여 세포 생존율, 염증 및 세포 사멸 관련 단백질 발현을 측정하였다. $H_2O_2$로 산화적 스트레스를 유도한 HPLF 세포에 무막줄기세포추출물 처리 시, $H_2O_2$만을 처리한 control군에 비해 유의적으로 세포 생존율이 증가함을 통해 산화적 손상에 대한 세포 보호 효과를 확인하였다. 또한, 무막줄기세포추출물은 nuclear factor kappa light chain enhancer of activated B cells, inducible nitric oxide synthase 및 interleukin-6와 같은 염증 관련 단백질 발현을 감소시켜 $H_2O_2$로 유도된 염증반응 보호 효과를 확인할 수 있었다. 뿐만 아니라, 무막줄기세포추출물 처리 군은 caspase-9, -3, poly (ADP-ribose) polymerase 단백질 발현 감소와 B-cell lymphoma 2 (Bcl-2)-associated X protein/Bcl-2 비율을 저하시켜 $H_2O_2$ 유도 산화적 손상에 대한 세포사멸 보호 효과를 보였다. 따라서 지방조직 유래 무막줄기세포추출물은 $H_2O_2$ 유도 산화적 손상에 대한 HPLF 세포의 염증반응 및 세포사멸을 저해함으로써 치주염으로부터 보호 효과가 있어, 치주질환 치료용 소재로써의 활용 가능성이 있을 것으로 기대된다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.74-74
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• 2003

Embryonic stem cells have several characteristics suitable for cell replacement therapy. To investigate a possibility of using human embryonic stem cell (hESC) as a carrier of therapeutic gene(s), hESC (MB03) was co-transfected with cDNAS coding for tyrosine hydroxylase (TH) and GTP cyclohydrolase Ⅰ (GTPCH Ⅰ) and bulk-selected using neomycin and hygromycin-B. Successful transfection was confirmed by western immunoblotting and RT-PCR. The genetically modified hESC (bk-THGC) relieved apomorphine-induced asymmetric motor behavior by approximately 54% when grafted into striatum of 6-OHDA-denervated rat brain. The number of rotation, however, increased up to 176+18% in 6 weeks when sham-grafted compared with number of rotation before graft. Immunohistochemical staining revealed that the grafted hESC survived and expressed TH for at least 6 weeks while the experiment was continued.