• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5529-5533
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• 2014

Background: The aim of this study was to investigate the effect of a c-myc antisense oligodeoxynucleotide and 5-fluorouracil on the expression of c-myc, invasion and proliferation of HEPG-2 liver cancer cells. Materials and Methods: HEPG-2 cells were treated with lipiosome-mediated c-myc ADSON and 5-fluorouracil. The proliferation inhibition rate and invasion were measured by MTT and invasion assay, respectively. Cell apoptosis was detected by flow cytometry and expression of c-myc by RT-PCR and immunohistochemistry. Results: The proliferation inhibition rate was significantly higher in the antisense oligodeoxynucleotide added-5-fluorouracil group than single antisense oligodeoxynucleotide or 5-fluorouracil group (p<0.05). G0/G1 cells in the antisense oligodeoxynucleotide group and S cells in the 5-fluorouracil groups were significantly increased than that in the control group, respectively (P<0.01). The amplification strips of PCR products in 5-FU, ASODN and combination groups were significantly weaker than that in the control group (P<0.01). The percentage of c-myc-protein-positive cells were significantly lower in antisense oligodeoxynucleotide, 5-fluorouracil and combination groups than that in the control group (P<0.01). Conclusions: A liposome-mediated c-myc antisense oligodeoxynucleotide and 5-fluorouracil can inhibit the proliferation and invasion of liver cancer cells by reducing the expression of c-myc. A c-myc antisense oligodeoxynucleotide can increase the sensitivity of liver cancer cells to 5-fluorouracil and decrease the dosage of the agent necessary for efficacy, providing an experimental basis for the clinical therapy of liver cancer.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.264-268
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• 1995

Sulforhodamine B(SRB) assay was performed on the human lung carcinoma, A549 cell line to screen soil microorganisms for production of anti-cancer agent. Among 4, 265 microorganisms, 45 isolates were selected for their cytotoxicity and tested for their effects on the expression of c-myc by RNA slot blot and Northern blot analysis resulting in selection of No.2303 isolate. This No.2303 was identified as Streptomyces sp. by ISP classification and the chemotaxonomic analysis method. NO.2303 inhibited the expression of cmyc in Col0320 DM and A549 cell lines. The culture extract of No. 2303 also inhibited the progression of the cell cycle of Go in NIH 313 cells, implying that the extract also inhibited the expression of c-myc in NIH 313 cell.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4883-4889
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• 2013

Background: The most common incident cancer and cause of cancer-related deaths in women is breast cancer. The Myc gene is upregulated in many cancer types including breast cancer, and it is considered as a potential anti-cancer drug target. The present study was conducted to evaluate the Myc (gene and protein) expression pattern in an experimental mammary tumour model in rats. Materials and Methods: Thirty six Sprague Dawley rats were divided into: Experimental group (26 animals), which received the chemical carcinogen N-methyl nitrosourea (MNU) and a control group (10 animals), which received vehicle only. c-Myc oncoprotein and its mRNA expression pattern were evaluated using immunohistochemistry (IHC) and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively, in normal rat mammary tissue and mammary tumours. The rat glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene was used as internal control for semi-quantitative RT-PCR. Results: Histopathological examination of mammary tissues and tumours from MNU treated animals revealed the presence of premalignant lesions, benign tumours, in situ carcinomas and invasive carcinomas. Immunohistochemical evaluation of tumour tissues showed upregulation and heterogeneous cellular localization of c-Myc oncoprotein. The expression levels of c-Myc oncoprotein were significantly elevated (75-91%) in all the tumours. Semi-quantitative RT-PCR revealed increased expression of c-Myc mRNA in mammary tumours compared to normal mammary tissues. Conclusions: Further large-scale investigation study is needed to adopt this experimental rat mammary tumour model as an in vivo model to study anti-cancer strategies directed against Myc or its downstream partners at the transcriptional or post-transcriptional level.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.352-361
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• 1996

The c-myc proto-onco9ene, one of the immediately early genes, is involved in ceflular proliferation and differentiation, and its biologleal function is regulated hy dimerization with a heterodimeric partner, myn. In the present study, gene expression patterns of c-myc and myn during mouse preimplantation embryo development were examined using a semi-quantitative reverse transcription-poiymerase chain reaction (RT-PCR). Myn transcripts were rather constitutively expressed throughout embryonic stages with a slight increase only at biastocyst stage. in contrast, expression of c-myc transcripts wm developmental stage-'pedfic. The c-myc transcripts were detected at 1-cell stage, declined abruptly at 2-cell stage and then increased gradually at blastocyst stage. To examine the possible role of myn during preimpiantation mouse embryo development, two myn antisense oligonucleotides spanning the tail of zipper dognain (myn2; 20-mer) and the second helix domain (myn3; 20-mer) were microinjected into the fertilized 1-cellembryos. Microinjection of myn2 and myn3 resulted in developmental tion at morula/biastocyst transition stage, leading to the fiagentation of embryos. Talien together, these results suggest that c-myc and its heterodimeric partner, myn, are differentially expressed In a developmental stage-dependent manner, and myn may play an important role in mouse preimpiantation embryo development.

• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.210-225
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• 1995

The expression of $p62^{c-myc}$ and $p21^{ras}$ can be seen in many solid tumor, but the pattern and incidence of expression were different according to organ, countries, and examiners, thus it is not definitely defined. Total 67 colorectal carcinoma in paraffin sections are analysed by immunohistochemically for evaluation of the $p62^{c-myc}$ and $p21^{ras}$ expression according to the age, sex, chief complaints, location, differentiation, modified Dukes stage, using the specific monoclonal antibodies. The results were summarized as follows : The age of patients ranged from 32 years to 82 years. The mean age was 57.6 years. The expression of $p62^{c-myc}$ and $p21^{ras}$ was not correlated with age. Male was 29 cases(43.3%) and female was 38 cases(56.7%). The male to female ratio was 1:1.31. The expression of $p21^{ras}$ was increased in female(p<0.05). Abdominal pain(43.7%) was the most frequent chief complaint. The most frequent tumor location was rectum(44.8%). The expression of $p62^{c-myc}$ was increased in the rectum(p<0.05). The 65 cases(97.0%) out of 67 cases showed positive reaction of $p62^{c-myc}$ in the nucleus, cytoplasmic membrane, and cytoplasm. The 62 cases(92.5%) out of 67 cases showed positive reaction of $p21^{ras}$ in the cytoplasmic membrane and cytoplasm. The positive rate of $p62^{c-myc}$ and $p21^{ras}$ was 97.0% and 91.4% in well differentiated adenocarcinoma, 100.0% and 95.0% in moderately differentiated adenocarcinoma, 90.0% and 90.0% in poorly differentiated adenocarcinoma, 100.0% and 100.0% in mucinous carcinoma. The positive rate of $p62^{c-myc}$ and $p21^{ras}$ was 94.1% and 88.2% in Dukes stage $B_1$, 96.0% and 96.0% in Dukes stage $B_2$, 100.0% and 100.0% in Dukes stage $C_1$, 100.0% and 88.9% in Dukes stage $C_2$, and 100.0% and 100.0% in Dukes stage D. The expression of $p62^{c-myc}$ in metastatic colorectal carcinoma showed diffuse and strongly positive reaction than primary colorectal carcinoma. The expression of $p21^{ras}$ in primary colorectal carcinoma showed diffuse and strongly positive reaction than metastatic colorectal carcinoma.

• Toxicological Research
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• v.15 no.1
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• pp.19-25
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• 1999

(+)-Catechin inhibited the growth and induced the differentiation of HL-60 human leukimia cells. The degree of a differentiation by (+)-catechin during the differentiation, the expression assay, To understand the molecular mechanism of (+)-catechin during the differentiation, the expression level of oncogenes was detected by Northern blot analysis. c-Myc mRNA level was reduced after treatment with (+)-Catechin (10-4), however, the expression of c-jun was increased with a concentration dependent manner in HL-60 cells. These results showed that the differentiation and antiproliferation of HL-60 cells against (+)-Catechin was related to the reduction of c-myc and the induction of c-jun expression.

• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.167-174
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• 1987

N-myc, a DNA sequence related to the oncogene c-myc, was found to be amplified in untreated primary neuroblastomas and the amplification appeared to be associated with advanced disease at diagnosis and rapid tumor progression. Synthetic peptides have been useful immunogens for generating antisera and monoclonal antibodies to a number of native proteins. In order to identify myc-related protein in the tumor cells, an antiserum against a synthetic hexapeptide (-Glu-Asp-Ile-Trp-Lys-Lys-), whose sequence corresponds to a part of the exon 2 of oncogene N-myc, was prepared by immunizing a rabbit with BSA-conjugated peptide. After ammonium sulfate precipitation and affinity column chromatography, it appeared to be specific to the peptide. Strong nuclear staining in immunoperoxidase method using this serum was observed in both human promyeloid leukemic cell line, HL-60(containing high c-myc copy number), and human neuroblastoma cell line, LA-N-5 (containing high N-myc copy number), whereas LA351 (human lymphoid cell line) cells did not react with the serum. This reaction was completely abrogated by incubating the antiserum with soluble excess peptide. These data suggest that the protein encoded by N-myc could be localized in the nucleus as c-myc protein and this antiserum can be used to detect myc-related tumor cells in clinical samples and to determine if the N-myc expression correlates with genomic amplification in cell lines, untreated primary tumors, and untreated metastases.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.91-97
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• 2018

This study has been conducted to see the expression of $TGF-{\beta}_1$, c-Myc, Erb-B2 and $Thymosin-{\beta}_4$ genes in ethanol - damaged liver tissues. Experimental groups were divided into 2 groups, one where damaged liver was caused by 25% ethanol and normal group administered with purified water. Results of test showed the expression of $TGF-{\beta}_1$, c-Myc, and $Thymosin-{\beta}_4$ genes was higher in the experimental group treated with 25% ethanol than in the normal group. Erb-B2 gene was not expressed clearly. Thus, it is considered that we can expect to utilize $TGF-{\beta}_1$, c-Myc 및 $Thymosin-{\beta}_4$ as auxiliary data and find clinical meanings of diagnosis on hepatic diseases, In addition to serologic and histological examination by convergence examining the gene expression status by molecular diagnostic techniques in liver-related disease prevention and diagnosis through results of this study.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.447-456
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• 2008

Background: Caspase-3 is a cysteine protease that plays a major role in the process of apoptotic cell death. The dysregulated expression of c-myc contributes to the tumorigenesis in a variety of human cancers. The aim of this study was to investigate the expressions of caspase-3 and c-myc and their significances as prognosis markers in patients with completely resected non-small cell lung cancer (NSCLC). Material and Method: A total 130 consecutive patients who had undergone complete resection without pre-operative radio-therapy or chemotherapy between May 1996 and December 2003 for NSCLC were retrospectively reviewed. The median follow-up period of the patients was 50 months (range: $3{\sim}128$ months). The expressions of caspase-3 and c-myc were immuno-histochemically examined, and these were correlated with the clinico-pathologic data. Result: The prevalence of caspase-3 and c-myc expressions in the patients was 68% (88/130) and 59% (77/130), respectively. Significant association was found between the frequency of the expressions of caspase-3 and c-myc (p=0.025). The caspase-3 and c-myc expressions were not significantly associated with the prognosis in all the patients. However, according to stages, a positive caspase-3 expression was significantly correlated with a favorable prognosis for patients with stage IIIa disease (median survival period: 35 months vs. 10 months, p=0.021). Multivariate analysis showed the pathologic stage to be significantly correlated with a good prognosis in all the patients (p=0.024), and with a positive caspase-3 expression, well differentiated tumor and negative neuronal invasion in the patients with stage llla disease (p=0.005, p=0.003, p=0.004, respectively). Conclusion: Caspase-3 and c-myc were frequently expressed in NSCLC, suggesting its possible involvement in tumor development. The caspase-3 expression, as determined with performing immunohistochemical staining, may be a favorable prognostic indicator in patients with completely resected NSCLC an advanced stage (IIIa).

• Journal of Life Science
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• v.23 no.10
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• pp.1216-1222
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• 2013

NK cells are lymphoid immune cells that participate in innate immunity to protect against foreign pathogens and transforming cells. It is known that the activity of NK cells is regulated by a balance between activating and inhibitory signals rather than specific antigens. One important activating signal is mediated by the NKG2D receptor, which recognizes NKG2D ligands on cancer cells. Therefore, tumor cells that express sufficient amounts of NKG2D ligands could be eliminated by NKD2D+ cells, including NK cells. Oncogenes drive tumor cells to apoptosis resistant and uncontrolled proliferation by altered expression of many critical genes. Therefore, the expression of NKG2D ligands may be affected by oncogenes. This study focused on increasing the susceptibility of cancer cells to NK cells by regulating the expression of NKG2D ligands influenced by three oncogenes: k-ras, wnt, and c-myc. We demonstrated that inhibition of k-ras and c-myc increased the expression of NKG2D ligands and enhanced the susceptibility of cancer cells to NK cells. On the contrary, inhibition of the wnt pathway decreased MICA and ULBP1 transcripts. Although the decreased transcription of NKG2D ligands by inhibition of the wnt pathway, surface proteins of NKG2D ligands were not changed, and the susceptibility of HCT-116 cells was unaffected. The results demonstrate that the transcription of NKG2D ligands are regulated deferentially by the k-ras, c-myc, and wnt pathways and that the cytotoxicity of NK cells solely depends on the amount of surface NKG2D ligands.