• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8461-8465
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• 2016

Gastric cancer (GC) as the fourth most common cause of malignancies shows high rate of morbidity appropriating the second leading cause of cancer-related death worldwide. Developmental pluripotency associated-2 (DPPA2), cancer-testis antigen (CT100), is commonly expressed only in the human germ line and pluripotent embryonic cells but it is also present in a significant subset of malignant tumors. To investigate whether or not DPPA2 expression is recalled in GC, our aim in this study was to elucidate DPPA2 protein expression in gastric cancer. Fifty five GC tumor and their related margin normal tissues were recruited to evaluate DPPA2 protein expression and its probable associations with different clinicopathological features of the patients. DPPA2 was overexpressed in GC cases compared with normal tissues (P < .005). While DPPA2 expression was detected in all GC samples, its high expression was found in 23 of 55 tumor tissues (41.8%). Interestingly, 50 of 55 normal samples (90.9%) were negative for DPPA2 protein expression and remained 5 samples showed very low expression of DPPA2. DPPA2 protein expression in GC was significantly correlated with lymph node metastasis (p = 0.012). The clinical relevance of DPPA2 in GC illustrated that high level expression of this protein was associated with lymph node metastasis supporting this hypothesis that alteration in DPPA2 was associated with aggressiveness of gastric cancer and may be an early event in progression of the disease. DPPA2 may be introduced as a new marker for invasive and metastatic GCs.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.449-455
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• 2011

Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by etopic expression of transcription factors. iPS cells are indistinguishable from ES cells in terms of morphology and stem cell marker expression. Moreover, mouse iPS cells give rise to chimeric mice that are competent for germline transmission. However, mice derived from iPS cells often develop tumors. Furthermore, the low efficiency of iPS cell generation is a big disadvantage for mechanistic studies. Nonviral plasmid.based vectors are free of many of the drawbacks that constrain viral vectors. The histone deacetylase inhibitor valproic acid (VPA) has been shown to improve the efficiency of mouse and human iPS cell generation, and vitamin C (Vc) accelerates gene expression changes and establishment of the fully reprogrammed state. The MEK inhibitor PD0325901 (Stemgent) has been shown to increase the efficiency of the reprogramming of human primary fibroblasts into iPS cells. In this report, we described the generation of mouse iPS cells devoid of exogenous DNA by the simple transient transfection of a nonviral vector carrying 2A-peptide-linked reprogramming factors. We used VPA, Vc, and the MEK inhibitor PD0325901 to increase the reprogramming efficiency. The reprogrammed somatic cells expressed pluripotency markers and formed EBs.

• 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.

• Reproductive and Developmental Biology
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• 제34권3호
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• pp.143-151
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• 2010

Pluripotency of human embryonic stem cell (hESC) is one of the most valuable ability of hESCs for applying cell therapy field, but also showing side effect, for example teratoma formation. When transplant multipotent stem cell, such as mesnchymal stem cell (MSC) which retains similar differentiation ability, they do not form teratoma in vivo, but there exist limitation of cellular source supply. Accordingly, differentiation of hESC into MSC will be promising cellular source with strong points of both hESC and MSC line. In this study, we described the derivation of MSC like cell population from feeder free cultured hESC (hESC-MSC) using direct differentiation system. Cells population, hESC-MSC and bone marrow derived MSC (BM-MSC) retained similar characteristics in vitro, such as morphology, MSC specific marker expression and differentiation capacity. At the point of differentiation of both cell populations, differentiation rate was slower in hESC-MSC than BM-MSC. As these reason, to verify differentially expressed molecular condition of both cell population which bring out different differentiation rate, we compare the molecular condition of hESC-MSC and BM-MSC using 2-D proteomic analysis tool. In the proteomic analysis, we identified 49 differentially expressed proteins in hESC-MSC and BM-MSC, and they involved in different biological process such as positive regulation of molecular function, biological process, cellular metabolic process, nitrogen compound metabolic process, macromolecule metabolic process, metabolic process, molecular function, and positive regulation of molecular function and regulation of ubiquitin protein ligase activity during mitotic cell cycle, cellular response to stress, and RNA localization. As the related function of differentially expressed proteins, we sought to these proteins were key regulators which contribute to their differentiation rate, developmental process and cell proliferation. Our results suggest that the expressions of these proteins between the hESC-MSC and BM-MSC, could give to us further evidence for hESC differentiation into the mesenchymal stem cell is associated with a differentiation factor. As the initial step to understand fundamental difference of hESC-MSC and BM-MSC, we sought to investigate different protein expression profile. And the grafting of hESC differentiation into MSC and their comparative proteomic analysis will be positively contribute to cell therapy without cellular source limitation, also with exact background of their molecular condition.

• 한국미생물·생명공학회지
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• 제39권4호
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• pp.364-373
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• 2011

인간배아줄기세포는 인간배아줄기세포가 가지는 전 분화능 등의 특이적 특성으로 인해 재생의학 분야에서 세포 치료제의 근원으로 널리 각광받고 있다. 그러나, 미분화 상태의 인간배아줄기세포를 세포치료제로 이용하기 위해서는 인간배아줄기세포 주 유래 기능성 세포를 확립이 반드시 요구된다. 본 연구에서는, 미분화 상태의 인간배아줄기세포주로부터 기능성 세포의 확립을 위해, 혈관계통의 세포로 분화를 유도하였으며, 분화 유도 후 세포의 크기 차이를 이용하여 특정 세포군 만을 분리하여 그 기능성을 비교 분석하였다. 그 결과, VEGF를 이용하여 분화 시킨 세포군에서 약 10%의 PECAM 양성 세포군을 확인할 수 있었으며, 분리 및 세포 이식을 위해 세포를 단일 세포군으로 만들었다. 단일 세포군의 형성 후, 유세포 분석기를 이용한 세포 분리 기법을 이용하여 FCS를 기준으로 한 세포 크기의 차이를 이용하여 특정 세포군 만을 분리하여, 하지 허혈 동물 모델로의 이식을 통해, 비 분리 세포군과 치료 효능을 비교 분석을 실시하였다. 세포 이식 4주 후, 혈류량 복구율이 FSC 기준 분리 군의 경우 54%, 비 분리군의 경우 17%를 보이는 것을 확인하였다. 이 결과는, 초기 분화 유도 후 세포 크기차이를 이용한 세포 분리법이 기능성 세포 획득에 이용될 수 있음을 시사한다. 이와 같은 방법을 통해 다양한 종류의 기능성 세포 분리에 이용될 수 있을 것이라 생각된다.

• 한국발생생물학회지:발생과생식
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• 제6권1호
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• pp.55-66
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• 2002

배아줄기세포(embryonic stem cell, ESC)는 미분화상태로 지속적인 계대가 가능하며, 정상 핵형과 전 분화능(pluripotency)을 가져 생체내-외에서 분화 유도시 삼배엽성의 모든 세포로 분화 가능하다. ESC를 feeder 세포 없이 부유배양하면 배아체(embryoid body, EB)를 형성하고, 초기 배아 발생과 유사한 분화 양상을 갖는다. ESC의 분화 유도가 초기배아 발생처럼 생식호르몬(GTH: FSH, LH; steroids)의 영향을 받는지는 불명하다. 본 연구는 ESC가 분화과정중 생식호르몬처리에 의해 그들 수용체가 발현되는가를 알아보고자 하였다. 순계혈통 생쥐인 C57BL/6J에서 과배란 유도후 포배를 수획하고, 유사분열적으로 불활성화된 feeder 세포와 공배양하여, 계대배양 하는 중 배아줄기세포주(JHYl)를 확립하였다. JHY1의 alkaline phosphatase 활성과 SSEA-1, 3, 4 발현을 통해 ESC임을 확인하였다. Feeder 세포 없이 ESC를 계대배양 후 호르몬처리(FSH LH E$_2$, P$_4$, T)하에서 5일 동안 부유배양하여 배아체를 형성시키고, 이후 7일 동안 부착배양하여 분화를 유도하였다. GTH와 스테로이드의 수용체 발현 실험에서 ESC에 E$_2$ 처리에 의한 LHR의 발현 증가를 제외한 나머지 호르몬 처리군에서 ESC보다 낮은 생식호르몬의 수용체 발현이 관찰되었다. 생식호르몬을 농도별 수용체 발현 정도는 증감되지 않았다. 미분화 ESC 표지유전자인 Oct-4는 호르몬 처리군에서도 발현되었다. 각 배엽의 표지유전자들(영양세포, handl; 외배엽성, keratin와fgf-5; 중배엽성, enolase와 $\alpha$ -globin; 내배엽성, gata-4와 $\alpha$ -fetoprotein) 등의 발현 양상을 조사한 결과 호르몬 처리후 내배엽성 표지유전자외에는 발현 증가가 관찰되지 않았다. 즉 생식호르몬에 의해 gata-4, $\alpha$-fetoprotein의 발현이 증가되는 것으로 보아 내배엽성 계열로의 분화 유도가 이루어진 것으로 사료된다.