• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2001.10b
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• pp.157-157
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• 2001

• BMB Reports
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• v.29 no.1
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• pp.73-80
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• 1996

The effect of albumin on phosphatidylcholine (PC) metabolism in Hep-G2, 3T3-H.ras, and 3T3 cells pre-labelled with [Me-$^3H$]choline was studied. The [$^3H$]choline was more efficiently taken up and incorporated into cellular phospholipids in 3T3-H.ras cells than in Hep-G2 and 3T3 cells. In each of the three cell lines, most of the [$^3H$]choline metabolized into the phospholipids was incorporated into PC and only minor was incorporated into lysophosphatidylcholine (LPC). Bovine serum albumin stimulated the release of [$^3H$]LPC and [$^3H$]PC from each of the three cell lines pre-labelled with [$^3H$]choline. [$^3H$]PC was also released in the absence of albumin but [$^3H$]LPC was not. The efficiency of LPC secretion represented as the proportion of medium [$^3H$]LPC to cellular [$^3H$]choline lipid during a chase period is approximately 9 to 14 times greater in 3T3 cells compared with the transformed 3T3-H.ras and Hep-G2 cells. A similar comparison of published data for rat hepatocytes with Hep-G2 shows secretion to be 35~75 times greater from the rat hepatocytes than from Hep-G2. Also, PC secretion from 3T3 cells was 1.6 times more effective than from 3T3-H.ras, whereas rat hepatocytes secrete PC 2.8~3.8 times more effectively than does Hep-G2. The measurement of specific radioactivity of cellular PC in pre-labelled 3T3 cells showed it to be similar to that of the secreted PC. However, the specific radioactivity of secreted LPC was markedly lower than that of the cellular PC, which suggests that LPC is being secreted from a PC pool distinct from that used for PC secretion.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.100-101
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• 2003

It has been known that elevated levels of COX-2 is associated with resistance to apoptosis in cancerous or transformed cells. However, recent studies have shown that up-regulation of COX-2 may be implicated in induction of apoptosis. Previous studies from this laboratory have shown that a novel alkylphospholipid type antitumor agent ET-18-O-$CH_3$ (l-O-octadecyl-2-0-methyl-glycero-3-phosphocholine) induces COX-2 expression in H-ras transformed human breast epithelial cells (MCF10A-ras) while it causes apoptosis in the same concentration range.(omitted)

• Advances in nano research
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• v.12 no.6
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• pp.605-616
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• 2022

We prepared two samples of ultrafine ferrihydrite (FH) nanoparticle ensembles of quite a different origin. First is the biosynthesized sample (as a product of the vital activity of bacteria Klebsiella oxytoca (hereinafter marked as FH-bact) with a natural organic coating and negligible magnetic interparticle interactions. And the second one is the chemically synthesized ferrihydrite (hereinafter FH-chem) without any coating and high level of the interparticle interactions. The interparticle magnetic interactions have been tuned by modifying the nanoparticle surface in both samples. The coating of the FH-bact sample has been partially removed by annealing at 150℃ for 24 h (hereinafter FH-annealed). The FH-chem sample, vice versa, has been coated (1.0 g) with biocompatible polysaccharide (arabinogalactan) in an ultrasonic bath for 10 min (hereinafter FH-coated). The changes in the surface properties of nanoparticles have been controlled by XPS. According to the electron microscopy data, the modification of the nanoparticle surface does not drastically change the particle shape and size. A change in the average nanoparticle size in sample FH-annealed to 3.3 nm relative to the value in the other samples (2.6 nm) has only been observed. The estimated particle coating thickness is about 0.2-0.3 nm for samples FH-bact and FH-coated and 0.1 nm for sample FH-annealed. Mössbauer and magnetization measurements are definitely shown that the drastic change in the blocking temperature is caused by the interparticle interactions. The experimental temperature dependences of the hyperfine field hf>(T) for samples FH-bact and FH-coated have not revealed the effect of interparticle interactions. Otherwise, the interparticle interaction energy E_int estimated from the hf>(T) for samples FH-chem and FH-annealed has been found to be 121k_B and 259k_B, respectively.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.92-98
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• 2010

Breast cancer has been estimated as one of the most common causes of cancer death among women. The major cause of death from breast cancer is the metastatic spread of the disease from the primary tumor to distant sites in the body. Lycopene is one of the major carotenoids in fruits and vegetables including tomatoes. Epidemiological studies have shown that the dietary intake of lycopene is associated with decreased risk of cancer. Although mounting evidence shows the chemopreventive effect of lycopene, the role of lycopene in the prevention of metastatic potential of breast cancer has not been determined yet. In the present study, we investigated the inhibitory effect of lycopene on invasive and migratory phenotypes of two highly aggressive breast cancer cell lines, H-Ras-transformed MCF10A human breast epithelial cells (H-Ras MCF10A) and MDA-MB-231 human breast cancer cells. Here, we report that lycopene significantly inhibits invasion and migration as well as proliferation of H-Ras MCF10A and MDA-MB-231 cells. This study suggested an in vitro anti-cancer and anti-metastatic potential of lycopene. We also showed that activations of ERKs and Akt were inhibited by lycopene in H-Ras MCF10A cells, suggesting that the ERKs and Akt signaling pathways may be involved in lycopene-induced anti-proliferative and/or anti-invasive/migratory effects in these cells. Taken in conjunction with the fact that breast cancer metastasis is one of the most lethal malignancies in women, our findings may provide useful information for the application of lycopene in establishing strategy to prevent the metastatic breast cancer.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.240-245
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• 2002

Cancer metastasis represents the most important cause of cancer death and antitumor agents that may inhibit this process have been extensively pursued. Invasion and metastasis of malignantly transformed cells involve degradation of the extracellular matrix (ECM) components by matrix metalloproteinases (MMP), especially MMP-2 and -9. We previously showed that H-ras-induced invasive phenotype may involve MMP-2, rather than MMP-9, in MCF10A cells. In the present study, we investigated the chemopreventive effect of Aster, a widely used culinary vegetable in Korea. We screened twelve extracts from three Aster species (Aster scaber, Aster oharai and Aster glehni) for the inhibitory effect on MMP activities of H-ras MCF10A human breast epithelial cells. All of the extracts tested in this study efficiently inhibited the gelatinolytic activities of MMP-2 and MMP-9. A more prominent inhibition was observed in MMP-2 activity compared to MMP-9. Out of twelve extracts, eight extracts showed>90％ inhibition of MMP-2 activity in H-ras MCF10A cells while only one extract showed>90％ inhibition of MMP-9 activity. We selected three extracts (AO-3, AG-3 and AS-EA) for further studies since they exerted a marked inhibition in the ratio of MMP-2 to MMP-9. Treatment with AO-3, AG-3 and AS-EA in H-ras MCF10A cells caused a significant inhibition of invasive phenotype and migration, proving a chemopreventive potential of these extracts. Taken together, our results demonstrate that extracts of Aster effectively inhibit invasion and migration of highly malignant human breast cells, possibly via downregulation of MMP-2 and MMP-9.

• Journal of Life Science
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• v.5 no.3
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• pp.105-116
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• 1995

To investigate genomic changes in c-myc gene by a chemical carcinogen, human lymphoblast NC-37 cells were exposed to benzo(a)pyrene(BP) and dimethylbenzanthracene(DMBA), and the c-myc gene expression was evaluated by Northern and Southern blot hybridization techniques. The results are as follows: When the genomic DNA of NC-37 cells exposed to several concentrations(1.25, 2.5 and 5ug/ml) of BP concentration. However, the c-myc gene was most significantly enhanced with 2.5ug/ml of BP. The expressions of c-myc gene in NC-37 cells was stimulated by BP and DMBA. Addition of TPA reduced the gene expression BP-treated cells, whereas it enhanced the gene expression in DMBA-treated cells. The expression of c-H-ras gene was slightly increased by treatment with BP and DMBA alone and in combination with TPA, however the magnitude of increase was not significantly different between each other. The expressions of c-myc c-H-ras genes in Burkitt's lymphoma cells were greater than those in NC-37 cells. When the DNA extracted from NC-37 cells exposed to various concentrations of BP were amplified by polymerase chain reaction using a primer set containing c-myc exon I, the amplified products were of the same size in all groups. To evaluate the BP toxicity in E.coli to which human c-myc gene-cloned pBR322 vector was inserted, Southern blot hybridization was conducted on c-myc genes digested with EcoRI/HindIII and Smal/Xbal restriction enzymes, and observing that in 2 ug/ml BP-treated cells a 3.5kb fragment was generated in addition to 1.3kb fragment which can be observed in normal cells. Direct nucleotide sequence analysis of polymerase chain reaction products showed a mutation of G$\longrightarrow$A transition at the Smal recognition site.

• BMB Reports
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• v.49 no.7
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• pp.370-375
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• 2016

Ras oncoproteins are small molecular weight GTPases known for their involvement in oncogenesis, which operate in a complex signaling network with multiple effectors. Approximately 25% of human tumors possess mutations in a member of this family. The Raf1/MEK/Erk1/2 pathway is one of the most intensively studied signaling mechanisms. Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases in a cell type- and stimuli-dependent manner. In the present study, using three inducible Ras-expressing NIH/3T3 cell lines, we demonstrated that MKP3 upregulation requires the activation of the Erk1/2 pathway, which correlates with the shutdown of this pathway. We also demonstrated, by applying pharmacological inhibitors and effector mutants of Ras, that induction of MKP3 at the protein level is positively regulated by the oncogenic Ras/Raf/MEK/Erk1/2 signaling pathway.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.174-180
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• 2011

Experiments were carried out to determine the role of Raf-1 kinase in the development of drug resistance to paclitaxel in v-H-ras transformed NIH 3T3 fibroblasts (Ras-NIH 3T3). We established a multidrug-resistant cell line (Ras-NIH 3T3/Mdr) from Ras-NIH 3T3 cells by stepwise increases in paclitaxel. Drug sensitivity assays indicated that the $IC_{50}$ value for drug-resistant Ras-NIH 3T3/Mdr cells was more than 1 ${\mu}M$ paclitaxel, 10- or more-fold higher than for the parental Ras-NIH 3T3 cells. Western blot and RT-PCR analysis showed that the drug efflux pump a P-glycoprotein were highly expressed in Ras-NIH 3T3/Mdr cells, while not being detectable in Ras-NIH 3T3 cells. Additionally, verapamil, which appears to inhibit drug efflux by acting as a substrate for P-glycoprotein, completely reversed resistance to paclitaxel in Ras-NIH 3T3/Mdr cell line, indicating that resistance to paclitaxel is associated with overexpression of the multidrug resistance gene. Interestingly, Ras-NIH 3T3/Mdr cells have higher basal Raf-1 activity compared to Ras-NIH 3T3 cells. Unexpectedly, however, the colocalization of Raf-1 and its negative regulator Spry2 was less observed in cytoplasm of Ras-NIH 3T3/Mdr cells due to translocation of Spry2 around the nucleus in the perinuclear zone, implying that Raf-1 may be released from negative feedback inhibition by interacting with Spry2. We also showed that shRNA-mediated knockdown of Raf-1 caused a moderate increase in cell susceptibility to paclitaxel. Thus, the results presented here suggest that a Raf-1-dependent pathway plays an important role in the development of acquired drug-resistance.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.457-461
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• 2018

Corpus luteum (CL) is a transient endocrinal tissue that undergoes repeated formation and regression during the estrous cycle. In this study, we hypothesized that the functional and structural mechanism of angiogenesis is similar between CL and tumor formation. First, we measured mRNA and protein expression of angiogenic receptors (vascular endothelial growth factor receptor-2, VEGFR2; Tie 2) in the early, middle, and late phase CL tissues during the estrous cycle. Ral-interacting protein of 76 kDa (RLIP76) and H-ras mRNA and protein were also expressed in the CL tissues. VEGFR2 and Tie 2 mRNA and protein were expressed in the early and middle phase CLs and decreased in the late phase. H-ras mRNA and protein were expressed in the early and middle phase CLs, but not in the late phase. RLIP76 mRNA was expressed in all phase CLs, and the protein expression was highest in early phase CLs. We suggest that RLIP76 and H-ras, an oncogenic gene, regulate the function of the CL during the estrous cycle, and the proteins will play an important role in the angiogenic mechanism of the CL.