• 약학회지
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• 제51권6호
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• pp.415-423
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• 2007

This study was to evaluate the genotoxic effects of airborne particulate matters using single cell gell elec trophoresis (comet assay) in A549 human lung carcinoma cells. The total suspended particulate (TSP) was collected on back-up filter in Chuncheon, Kangwon Do, South Korea from April, 2003 to February, 2005. The concentrations of TSP, B(a)p and most of heavy metals seemed to be higher in spring and winter, and lower in summer. And they showed higher concentration in the commercial areas and the residential area having more traffics than in the rural area. It was found that A549 cells interacting with the organic extract of TSP showed more DNA single-strand breaks compare to untreated cells. The genotoxicity of the organic extract of TSP was increased with the pre-treatment of S-9 mixture during the culture or with the treatment of endonuclease after cell lysis. The DNA damage by the organic extract of TSP was higher in winter and the commercial area than in summer and the rural area. This study suggests that TSP, heavy metals and B(a)P analyzed showed significant variation depend on the seasons and the areas which are correlated with the DNA damage evaluated by Comet assay, indicating that genotoxic biomarker is useful for toxicological evaluation of air quality.

• BMB Reports
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• 제54권2호
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• pp.98-105
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• 2021

The clustered regularly interspaced short palindromic repeats (CRISPR) system is a family of DNA sequences originally discovered as a type of acquired immunity in prokaryotes such as bacteria and archaea. In many CRISPR systems, the functional ribonucleoproteins (RNPs) are composed of CRISPR protein and guide RNAs. They selectively bind and cleave specific target DNAs or RNAs, based on sequences complementary to the guide RNA. The specific targeted cleavage of the nucleic acids by CRISPR has been broadly utilized in genome editing methods. In the process of genome editing of eukaryotic cells, CRISPR-mediated DNA double-strand breaks (DSB) at specific genomic loci activate the endogenous DNA repair systems and induce mutations at the target sites with high efficiencies. Two of the major endogenous DNA repair machineries are non-homologous end joining (NHEJ) and homology-directed repair (HDR). In case of DSB, the two repair pathways operate in competition, resulting in several possible outcomes including deletions, insertions, and substitutions. Due to the inherent stochasticity of DSB-based genome editing methods, it was difficult to achieve defined single-base changes without unanticipated random mutation patterns. In order to overcome the heterogeneity in DSB-mediated genome editing, novel methods have been developed to incorporate precise single-base level changes without inducing DSB. The approaches utilized catalytically compromised CRISPR in conjunction with base-modifying enzymes and DNA polymerases, to accomplish highly efficient and precise genome editing of single and multiple bases. In this review, we introduce some of the advances in single-base level CRISPR genome editing methods and their applications.

• 치위생과학회지
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• 제23권3호
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• pp.216-224
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• 2023

Background: Smilax glabra has various pharmacological activities and is widely used as a herbal medicine. Although the incidence of oral cancer is low, the recurrence rate is high, and the 5-year survival rate is poor. It is necessary to search for anticancer drugs that increase the effect of cancer chemotherapy on heterogeneous oral tissues and reduce the side effects on normal cells. This study aimed to investigate the effects and mechanism of ethanol extract of Smilax glabra (EESG) as an anticancer drug for oral cancer. Methods: Smilax glabra root components extracted with 70% ethanol were used to analyze their effects on cancer cells. A 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide assay was performed for cytotoxicity analysis. Flow cytometry was performed to determine the cell cycle phase distribution. To observe apoptotic cells, terminal deoxynucleotidyl transferase dUTP nick end labeling and γH2AX were detected by fluorescence microscope. The protein levels of cleaved PARP and caspase were analyzed using western blotting. The activation of procaspase-3 was confirmed by measuring caspase-3 activity. Results: EESG was no cytotoxic to normal gingival fibroblast but was high in YD10B oral squamous cell carcinoma (OSCC) cells. EESG treatment increased the subdiploid DNA content of YD10B cells by assessing DNA content distribution. Chromatin condensation and DNA strand breaks increased in YD10B cells treated with EESG. EESG-treated YD10B cells had high Annexin V and low propidium iodide levels, confirming that early apoptosis was induced. In addition, increased levels of γH2AX foci, a marker of DNA damage, were observed in the nuclei of EESG-treated YD10B cells. The EESG-treated YD10B cells also exhibited decreased procaspase-3 and procaspase-9 levels, increased PARP cleavage and caspase-3 activity. Conclusion: These results indicate that EESG inhibited cancer cell proliferation by inducing apoptosis in YD10B OSCC cells.

• 한국식품과학회지
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• 제31권4호
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• pp.1071-1076
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• 1999

본 연구에서는 김치발효에 관여하는 우세 발효균들의 집락을 분리하고, 발암원인 MNNG에 대하여 이들 분리주들이 갖는 DNA 손상 억제효과를 조사하였다. 이를 위해서 세포의 DNA 손상 및 복구를 측정하는데 이용되는 매우 신속하고 감도가 높은 Single Cell Gel Electrophoresis(SCGE 법, 또는 comet assay)를 사용하였다. 배추김치에서 분리한 3개의 분리주중에서 B-3를 제외한 B-1과 B-2는 양성 대조구와 비교하였을 때 우수한 항유전 독성효과를 나타내었으며(p<0.01), 율무김치의 3 개의 분리주(Y-1, Y-2, Y-3)와 1개의 분리주(Y-4)도 각각 항유전 독성효과를 나타내었다(p<0.05, p<0.01). 총각김치의 5 개 분리주중에서 3개의 분리주와 깍두기의 9개의 분리주중에서 2 개의 분리주들도 각각 항유전 독성효과를 나타내었다(p<0.05, p<0.01).

• 대한화장품학회지
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• 제24권1호
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• pp.74-86
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• 1998

자외선에 의한 유전독성의 감소에 미치는 홍삼추출물의 영향을 배양 NIH3T3 세포계에서 분석하였다. 자외선을 조사한 후 정상 배지에서 배양한 시간간격에 따라 세포의 생존률은 증가하였는데 홍삼추출물이 함유된 배지에서 배양한 경우는 약 15%정도 증가한 생존률을 보였다. 자외선을 조사한 후 감소된 DNA복제가 정상배지 배양시간에 따라 증가하는 정도도 홍삼추출물을 후처리할 경우 현저한 증가를 보였다. 자외선 상해를 회복하기 위한 절제회복능은 홍삼추출물을 처리할 경우 유의미한 증가를 보였다. 이러한 절제회복과정 중 효소에 의한 절제단계가 홍삼추출물 처리에 의해 활성화됨을 단사절단 분석을 통하여 규명하였다. 이상의 결과는 홍삼추출물이 자외선 상해의 절제회복에 유의미한 증가를 보이며 따라서 유전독성을 감소시키는 항노화제로써 사용할 수 있음을 시사한다.

• The Korean Journal of Physiology and Pharmacology
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• 제7권1호
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• pp.9-14
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• 2003

Recent studies indicated that cancer cells become resistant to ionizing radiation (IR) and chemotherapy drugs by enhanced DNA repair of the lesions. Therefore, it is expected to increase the killing of cancer cells and reduce drug resistance by inhibiting DNA repair pathways that tumor cells rely on to escape chemotherapy. There are a number of key human DNA repair pathways which depend on multimeric polypeptide activities. For example, Ku heterodimer regulatory DNA binding subunits (Ku70/Ku80) on binding to double strand DNA breaks (DSBs) are able to interact with 470-kDa DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and are essential for DNA-dependent protein kinase (DNA-PK) activity. It has been known that DNA-PK is an important factor for DNA repair and also is a sensor-transmitting damage signal to downstream targets, leading to cell cycles arrest. Our ultimate goal is to develop a treatment of breast tumors by targeting proteins involved in damage-signaling pathway and/or DNA repair. This would greatly facilitate tumor cell cytotoxic activity and programmed cell death through DNA damaging drug treatment. Therefore, we designed a domain of Ku80 mutants that binds to Ku70 but not DNA end binding activity and used the peptide in co-therapy strategy to see whether the targeted inhibition of DNA-PK activity sensitized breast cancer cells to irradiation or chemotherapy drug. We observed that the synthesized peptide (HNI-38) prevented DNA-PKcs from binding to Ku70/Ku80, thus resulting in inactivation of DNA-PK activity. Consequently, the peptide treated cells exhibited poor to no DNA repair, and became highly sensitive to IR or chemotherapy drugs, and the growth of breast cancer cells was inhibited. Additionally, the results obtained in the present study also support the physiological role of resistance of cancer cells to IR or chemotherapy.

• 생명과학회지
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• 제13권3호
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• pp.241-247
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• 2003

DNA 손상 유발을 위해 cisplatin, mitomycin 그리고 adriamycin을 농도별로 처리하여 세포독성 효과 및 세포주기 분포를 조사하였다. 이들 약제중 adriamycin의 감수성이 가장 높았으며 특히 $Ku80^{-/-}MEFs$가 현저한 세포독성 감수성 효과를 나타내었다. DNA 회복과 관련된 S phase의 분포도를 알아보기 위하여 adriamycin을 처리한 결과 DNA-$PKcs^{-/-}MEFs$와 $Ku80^{-/-}MEFs$ 모두에서 S phase는 대조군과 비슷하게 나타났다. 그리고 DNA$PKcs^{-/-}MEFs$에 adriamycin 처리시 6시간 경과 후 $G_2$/M phase가 증가되었으나 30시간 경과시 정상으로 회복되었다. 그러나 $Ku80^{-/-}MEFs$는 6시간 경과 이후 36시간 경과시 까지 $G_2$/M phase가 지속적으로 증가하다 결국 사멸되었다. 따라서 Ku80는 세포주기 조절 유전자의 발현을 위해 필수적인 단백질이며 Ku80의 결핍은 $G_2$M phase에서 다음 단계로의 세포주기 변화를 상실하여 사멸하게 된다. 그러므로 $Ku80^{-/-}MEFs$가 대조군과 다른 반응을 나타내는 것은 DNA 회복정도의 차이에서 오는 것이 아니라 세포주기 조절유전자 발현의 차이에서 오는 것으로 사료된다.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 춘계학술대회
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• pp.185-185
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• 2003

To develope the novel anti-allergic drug, many sophoricoside derivatives were synthesized. Among these derivatives, JSH-II-3, JSH-Ⅵ-3, JSH-Ⅶ-3, and JSH-Ⅷ-3 were selected and subjected to high throughput toxicity screening (HTTS) because they revealed strong IL-5 inhibitory activity and limitation of quantity. Mouse lymphoma thymidine kinase (tk$\^$+/-/) gene assay (MOLY) and single cell gel electrophoresis (Comet) assay in mammalian cells were used as HTTS tool in our laboratory. In MOLY assay, JSH-Ⅶ-3 at 50 ∼ 6 $\mu\textrm{g}$/ml concentrations was not shown significant mutagenic effect in the absence and presence of S-9 metabolic activation system. However, the concentration of ISH-II-3, 38 $\mu\textrm{g}$/ml, induced increased mutation frequency (MF) in the presence of S-9 metabolic activation system. Also in comet assay, DNA damage was not observed in JSH-Ⅵ-3 and JSH-Ⅶ-3, wherase concentration of 32.8 $\mu\textrm{g}$/ml in JSH-II-3 and 13.9 $\mu\textrm{g}$/ml in JSH-Ⅶ-3 were induced DNA damage in the absence of S-9 metabolic activation system. Therefore, we suggest that JSH-Ⅵ-3 and JSH-Ⅶ-3 have no genotoxic effects but JSH-II-3 and JSH-Ⅷ-3 induce some mutagenicity and DNA strand breaks in mouse lymphoma cell line used this study.

• Toxicological Research
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• 제29권1호
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• pp.35-42
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• 2013

Quantum dots (QDs) have received considerable attention due to their potential role in photosensitization during photodynamic therapy. Although QDS are attractive nanomaterials due to their novel and unique physicochemical properties, concerns about their toxicity remain. We suggest a combination strategy, CdSe/ZnS QDs together with curcumin, a natural yellow pigment from turmeric, to reduce QD-induced cytotoxicity. The aim of this study was to explore a potentially effective cancer treatment: co-exposure of HL-60 cells and human normal lymphocytes to CdSe/ZnS QDs and curcumin. Cell viability, apoptosis, reactive oxygen species (ROS) generation, and DNA damage induced by QDs and/or curcumin with or without ultraviolet A (UVA) irradiation were evaluated in both HL-60 cells and normal lymphocytes. In HL-60 cells, cell death, apoptosis, ROS generation, and single/double DNA strand breaks induced by QDs were enhanced by treatment with curcumin and UVA irradiation. The protective effects of curcumin on cell viability, apoptosis, and ROS generation were observed in normal lymphocytes, but not leukemia cells. These results demonstrated that treatment with QD combined with curcumin increased cell death in HL-60 cells, which was mediated by ROS generation. However, curcumin acted as an antioxidant in cultured human normal lymphocytes.

• Molecular & Cellular Toxicology
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• 제1권4호
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• pp.230-236
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• 2005

Formaldehyde is a common environmental contaminant found in tobacco smoke, paint, garments, diesel and exhaust, and medical and industrial products. Formaldehyde has been considered to be potentially carcinogenic, making it a subject of major environmental concern. However, only a little information on the mechanism of immunological sensitization and asthma by this compound has been known. So, we performed with Jurkat cell line, a human T lymphocyte, to assess the induction of DNA damage and to identify the DEGs related to immune response or toxicity by formaldehyde. In this study, we investigated the induction of DNA single strand breaks by formaldehyde using single cell gel electrophoresis assay (comet assay). And we compared gene expression between control and formaldehyde treatment to identify genes that are specifically or predominantly expressed by employing annealing control primer (ACP)-based $GeneFishing^{TM}$ method. The cytotoxicity ($IC_{30}$) of formaldehyde was determined above the 0.65 mM in Jurkat cell in 48 h treatment. Based on the $IC_{30}$ value from cytotoxicity test, we performed the comet assay in this concentration. From these results, 0.65 mM of formaldehyde was not revealed significant DNA damages in the absence of S-9 metabolic activation system. And the one differentially expressed gene (DEG) of formaldehyde was identified to zinc finger protein 292 using $GeneFishing^{TM}$ method. Through further investigation, we will identify more meaningful and useful DEGs on formaldehyde, and then can get the information on the associated mechanism and pathway with immune response or other toxicity by formaldehyde exposure.