• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.72-77
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• 2004

Previously, we synthesized a novel Cyclin-dependent kinase inhibitor, MCS-5A. Also, we investigated the involvement of cell cycle regulatory events during MCS-5A-mediated apoptosis in HL-60(+p16/-p53) cells with up-regulation of p16 protein expression. In contrast, apoptosis was not observed in A549(-p16/+p53) cells. Therefore we propose that $p16^{INK4A}$ is a key enzyme for inducing apoptosis. In the present studies, we have explored the mechanism of $p16^{INK4A}$ -mediated cytotoxicity and the role of p16.sup INK4A/ overexpression in the induction of apoptosis in human tumor cells. The tumor suppressor gene $p16^{INK4A}$ is known as a cyclin-dependent kinase inhibitor (CKI) and cell cycle regulator. We expressed wild type $p16^{INK4A}$ in pcDNA3.1 vector and then transfected into non-small cell lung cancer (NSCLC) cell expressing different statue of p16$^{INK4A}$, p53 gene〔A549(-p16/+p53), H1299(-p16/-p53) and HeLa(+pl6/+p53) cell line〕. TUNEL assay (including propidium iodide staining following transfection of these cell line with pcDNA3.1-pl6) indicate that p16$^{INK4A}$-mediated cytotoxicity was associated with apoptosis. This is supported by studies demonstrating an induction of caspase 3 cleavage due to the transfection of A549, H1299 and HeLa cells with pcDNA3.1-pl6. These results suggest that p16$^{INK4A}$ has a new function of inducing apoptosis which is not related with the function of tumor suppressor gene p53.

• Journal of Plant Biology
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• v.34 no.2
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• pp.129-136
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• 1991

Two cell types, tip cells and hyphal cells, were found at the front of Cuscuta australis endophyte growing into the stem parenchyma of the host plant, Trifolium repens. Each tip cell developed into an elongate, filamentous hypha. The cells of both types possessed a dense cytoplasm including abundant organelles and enlarged nuclei with the deeply lobed envelope. The unevenly thick walls were observed in certain tip cells. The wall penetrated through the middle lamellae of the host cells and engulfed the debris of broken host cells. Some front cells had the plasmalemma-wall invaginations, which increased the surface area and would facilitate material uptake from the host No plasmodesmata between the host and parasite cells were found; instead, an apoplastic continuity was established by fused cell walls at the interface of the two partners. The apoplast was thought to be the main route for water and nutrients transport.nsport.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.163-170
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• 2001

Purpose : The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Materials and Methods : Four human cancer cell lines - PCI-1, SNU-1066, NCI-H630 and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy. For clonogenic assay, cells in $25\;cm^2$ flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for $10\~14$ days. For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. Results : There was minimal variation in the values gained from these two methods with the standard deviation generally less than $5\%$, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the $R^2$ value of $0.975\~0.992$ between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than $30\%$). For cells with low plating efficiency (less than $30\%$), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was after 6 doubling times for the results compatible with those of clonogenic assay, at least after 4 doubling times was required for valid results. In consideration of practical limits of assay (12 days, in this study) cells with doubling time more than 3 days were inappropriate for application. Conclusion : In conclusion, it is found that MTT assay can successfully replace clonogenic assay of tested cancer cell lines after irradiation only if MTT assay was undertaken with optimal assay conditions that included plating efficiency of each cell line and doubling time at least.

• Journal of Life Science
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• v.25 no.4
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• pp.441-449
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• 2015

Endlicheria anomala, a neotropical plant, is found in northern South America and the Amazon region. It is traditionally used to remove poisons and cure gangrene. According to recent data, this plant has diverse biological properties such as anti-oxidative, anti-inflammatory and anti-melanogenic properties. However, the anti-cancer effect of E. anomala and its molecular mechanisms remain unclear. In this study, we examined the anti-cancer effect and the active mechanism of methanol extract of E. anomala (MEEA) in human lung adenocarcinoma cells (A549) and human liver cancer cells (HepG2). Our data revealed that MEEA showed cytotoxic activity in a dose-dependent manner and induced apoptosis both in A549 and HepG2 cells. We verified evidences of apoptosis via formation of chromatin condensation, apoptotic body and accumulation of cells in the subG1 phase. Following observed apoptosis-related phenomena, we found that the induction of apoptosis by MEEA was associated with the increase of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 (WAF1/CIP1) expression. Furthermore, MEEA-induced apoptosis was characterized with proteolytic activation of caspase-3, degradation of poly ADP ribose polymerase (PARP), and up-regulation of pro-apoptotic Bax expression. Taken together, these findings indicate that MEEA may have potential cancer therapeutic utility in A549 and HepG2 cells.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.391-398
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• 2018

Mesenchymal stem cells (MSCs) are an attractive resource for refractory patients because of their anti-inflammatory/immunomodulatory capability and multi-lineage differentiation potential. The transplantation of MSCs has led to positive results in preclinical and clinical application to various diseases, including autoimmune disease, cardiovascular disease, cancer, liver cirrhosis, and ischemic stroke. On the other hand, studies have shown that paracrine factors, not direct cell replacement for damaged cells or tissue, are the main contributors in MSC-based therapy. More recently, evidence has indicated that MSC-derived exosomes play crucial roles in regulating the paracrine factors that can mediate tissue regeneration via transferring nucleic acids, proteins, and lipids to the local microenvironment and cell-to-cell communication. The use of these exosomes is likely to be beneficial for the therapeutic application of MSCs because their use can avoid harmful effects, such as tumor formation involved in cell transplantation. Therefore, therapeutic applications using MSC-derived exosomes might be safe and efficient strategies for regenerative medicine and tissue engineering. This review summarizes the recent advances and provides a comprehensive understanding of the role of MSC-derived exosomes as a therapeutic agent.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.383-393
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• 2008

Purpose: Cancer specific killing can be achieved by therapeutic gene activated by cancer specific promotor. Expression of sodium iodide symporter (NIS) gene causes transportation and concentration of iodide into the cell, therefore radioiodine treatment after NIS gene transfer to cancer cell could be a form of radionuclide gene therapy. luciferase (Luc) gene transfected cancer cell can be monitored by in vivo optical imaging after D-luciferin injection. Aims of the study are to make vector with both therapeutic NIS gene driven by AFP promoter and reporter Luc gene driven by CMV promoter, to perform hepatocellular carcinoma specific radiodiodine gene therapy by the vector, and assessment of the therapy effect by optical imaging using luciferase expression. Materials and Methods: A Vector with AFP promoter driven NIS gene and CMV promoter driven Luc gene (AFP-NIS-CMV-Luc) was constructed. Liver cancer cell (HepG2, Huh-7) and non liver cancer cell (HCT-15) were transfected with the vector using liposome. Expression of the NIS gene at mRNA level was elucidated by RT-PCR. Radioiodide uptake, perchlorate blockade, and washout tests were performed and bioluminescence also measured by luminometer in these cells. In vitro clonogenic assay with 1-131 was performed. In vivo nuclear imaging was obtained with gamma camera after 1-131 intraperitoneal injection. Results: A Vector with AFP-NIS-CMV-Luc was constructed and successfully transfected into HepG2, Huh-7 and HCT-15 cells. HepG2 and Huh-7 cells with AFP-NIS-CMV-Luc gene showed higher iodide uptake than non transfected cells and the higher iodide uptake was totally blocked by addition of perchlorate. HCT-15 cell did not showed any change of iodide uptake by the gene transfection. Transfected cells had higher light output than control cells. In vitro clonogenic assay, transfected HepG2 and Huh-7 cells showed lower colony count than non transfected HepG2 and Huh-7 cells, but transfected HCT-15 cell did not showed any difference than non transfected HCT-15 cell. Number of Huh-7 cells with AFP-NIS-CMV-Luc gene transfection was positively correlated with radioidine accumulation and luciferase activity. In vivo nuclear imaging with 1-131 was successful in AFP-NIS-CMV-Luc gene transfected Huh-7 cell xenograft on nude mouse. Conclusion: A Vector with AFP promoter driven NIS and CMV promoter driven Luc gene was constructed. Transfection of the vector showed liver cancer cell specific enhancement of 1-131 cytotoxicity by AFP promoter, and the effect of the radioiodine therapy can be successfully assessed by non-invasive luminescence measurement.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.517-517
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• 2013

세포막지질의 산화는 심각한 세포막의 기능저하를 유발하고 심하면 세포를 죽음에 이르게하여 생물학적으로 중요한 지표이다. 세포막지질의 산화는 간접적인 화학적 방법으로 측정하거나, 지질을 추출해내어 질량분석기나 핵자기공명분광기 같은 물리적 방법으로 분석한다. 우리는 이온유도 이차전자 방출계수(${\gamma}$) 변화를 측정하여 세포막지질의 산화를 지질추출 없이 측정할 수 있는지 조사해 보았다. 세포막분리가 쉬운 적혈구를 모델세포로 사용하였고, 다양한 라디칼을 발생시키는 대기압 공기 DBD플라즈마 장치를 이용하였다. 적혈구를 플라즈마에 노출하는 시간으로 산화의 정도에 차이를 만들어 측정값과 비교하였다. ${\gamma}$값은 Auger의 중화이론에 바탕을 둔 이온유도 이차전자 방출빔(${\gamma}$-FIB)장비를 이용하여 측정하였다. 측정결과 적혈구가 산화됨에 따라서 ${\gamma}$값이 증가함을 볼 수 있었고, 동시에 workfunction값이 변화함을 보았으며, 그 결과를 화학적 방법과 비교해 보았다.

• The Microorganisms and Industry
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• v.20 no.2
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• pp.33-40
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• 1994

미생물에 대한 유전자 재조합법 등의 개발로 동물세포에서만 합성되던 단백질들을 미생물을 통하여 생산하는 기술이 확립되어 있으나, 동물 세포내에서만 정확하게 실행되어지는 단백질 분자의 folding과 post-translational modification 등이 미생물에서는 불완전하게 이루어져 활성을 잃게 되는 단점이 있고, pyrogen과 같이 미생물로부터 유래한 endotoxin이 생산물에 섞여 있을수도 있으며, 미생물로부터 생산되는 각종 단백질로부터 원하는 유용 단백질을 분리하기 어려운것 등, 현실적으로 많은 어려움을 가지고 있기 때문에 미생물을 이용하기보다 동물 세포 배양을 통하여 위와 같은 제재들을 생산하려 하고 있다. 유전자 재조합 기술은, 현재 미생물뿐만 아니라, 동,식물 세포에 대하여도 적용되어 있어서 각종 유용생산물을 동,식물세포의 유전자 조작을 통해 얻을 수 있는 단계에 와 있으며, 이는 유전자 치료(gene therapy)와 같은 의료분야에까지 확장될 수 있게 되었다. 표 2에서는 동물 세포를 배양할 때와 미생물을 이용할 때의 각각의 특징을 보여주고 있다.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.190-194
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• 1995

체성-교감 반사 유발시 동맥혈압의 조절에 관여한다고 생각되는 상부 복외측 연수 내의 심혈관계 세포를 대상으로 흥분발사의 반응특성을 측정, 분석하였다. 심장 박동주기와 시간적으로 동기되는 흥분발사를 보이는 심혈관계 세포를 찾은 후 체성-교감 반사의 승압반응과 감압반응을 유발시키며 각각에 대해 동일한 세포의 흥분발사의 변화를 측정한 결과 5가지 유형의 반응특성을 얻을 수 있었다. 이들 간에 구성되어 있는 회로망 연결을 설명하고자 2 가지 종류의 특성 세포와 적절한 자극 전달 경로 및 세포간 회로망 연결을 도입하여 본 연구의 실험결과를 모두 설명할 수 있는 가장 간단한 죄소 세포회로망 모델을 구성하였다. 최소 모델의 고찰 결과 고유한 감압경로의 존재가능성이 도출되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.751-753
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• 2010

본 논문에서는 위상차 현미경 영상 내 U87 세포의 정확한 형태학적 분류를 위한 이진 분류기 구축 방법을 제안한다. 본 방법은 Fourier descriptor 기반 세포형상 표현을 SVM 이진분류기 구축에 사용함으로써 분류 대상인 원추형과 원형세포에 대해 영상 내 세포의 위치와 회전, 크기의 변화에 대해 강인한 분류성능을 제공한다. 본 실험을 통해 polynomial 커널에서 학습된 SVM 분류기가 linear, RBF, sigmoid 에 비교하여 가장 정확한 분류 성능을 보임을 확인하였다. 본 연구는 논문상 기준인 두 종류의 세포 형태 분류기를 기반 프레임워크로 삼아 좀더 다양한 세포 형태를 분류할 수 있도록 개선된다면 악성뇌종양의 전이억제치료에 효과적인 전이행동분석에 도움을 줄 수 있을 것으로 기대된다.