• The Korean Journal of Nuclear Medicine
• /
• v.34 no.2
• /
• pp.144-153
• /
• 2000

Purpose: The purpose of this study was to evaluate the relationship between radiation-induced activation of DNA repair genes and radiation induced apoptosis in A431 cell line. Materials and Methods: Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. Results: The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and hRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, hRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Conclusion: Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. hRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.

• KSBB Journal
• /
• v.24 no.3
• /
• pp.217-226
• /
• 2009

p53 undergoes various post-translational modifications, including phosphorylation, ubiquitination, sumoylation, acetylation, methylation, and poly(ADP-ribosyl)ation. Modification of p53 widely affects to various functions of p53. Acetylation and phosphorylation of p53 have been studied for regulating its transcriptional activity which is observed in various stress condition. Otherwise, ubiquitination of p53 by Mdm2 has been well-studied as a canonical ubiquitin-mediated proteasomal degradation pathway. Moreover several investigators have recently reported that ubiquitination of p53 modulates not only its proteasome-dependent degradation by poly-ubiquitination but also its localization and transcriptional activity by mono-ubiquitination which usually does not serve the proteasome dependent degradation. Here we review recent studies on the cellular functions of p53 regulated by post-translational modifications, particularly focusing on mechanisms of ubiquitination.

• Journal of Gastric Cancer
• /
• v.6 no.4
• /
• pp.214-220
• /
• 2006

Purpose: p53 is one of the most commonly mutated genes in human tumors. The aim of this study was to analyze p53 mutation in gastric cancer and its correlations with the clinicopathologic variables to clarify the usefulness of p53 mutation as a prognostic factor. Materials and Methods: Specimens from 331 patients with gastric cancer who underwent a gastrectomy between March 1999 and April 2001 at the Kyungpook National University Hospital were used. p53 gene mutations were assessed by using a polymerase chain-reaction single-strand conformation polymorphism (PCR-SSCP) analysis. The correlations between p53 gene mutation and clinocopathologic parameters were analyzed. Results: p53 mutations were found in 66 (19.9%) tumors. Among those 66 cases, mutations were seen in 23 tumors at axon 5, in 8 at exon 6, in 21 at exon 7, and in 17 at exon 8. Two mutations were shown in 3 tumors. Thiriy-six (23.1%) of 156 intestinal-type tumors and 19 (13.1%) of 145 diffuse-type tumors showed p53 gene mutation (P=0.007). The frequency of p53 gene mutation didn't show any significant differences according to age, sex, stage, location, or gross type. Exon 5 mutations showed more frequently in intestinal-type tumors than in diffuse-type tumors (9.7% vs. 2.8%, P=0.024), and p53 mutation were more frequent in lymph nodes metastasis group than lymph nodes non-metastasis group with statistical significance (25.0% vs 15.6%, P=0.034). The five-year survival rate showed no statistically significant difference with p53 mutation (P=0.704). Conclusion: p53 mutations assessed by PCR-SSCP had little value as a prognostic factor after gastrectomy in patients with gastric cancer.

• Journal of the Korean Chemical Society
• /
• v.50 no.2
• /
• pp.116-122
• /
• 2006

In this study we extracted DNA from 100 tissues of breast cancer patients and 103 normals. Then we confirmed single-nucleotide polymorphism(SNP) using PCR-DHPLC(polymerase chain reaction-denaturing high performance liquid chromatogrphy).Also, we studied SNP of samples using several columns to identify relation between packing materials of column and resolution.As a result, we identified 4 C/A, C/G genotypes(4%) in exon 5 and 37 T del genotypes(37%) in exon 8 among 100 breast cancer tissues and 2 in exon 5, 9 in exon 8 among 103 normal samples.In resolution test, we confirmed that PS-DVB(poly styrene-divinylbenzen) column is more efficient than C18 column.

• Journal of Chest Surgery
• /
• v.36 no.11
• /
• pp.852-857
• /
• 2003

Background: Conventional treatment for mesothelioma is largely ineffective. We evaluated the novel approach of adenoviral gene transfection of PTEN gene in mesothelioma cancer cell lines, inflammatory and epithelial subtype, which are sensitive to adenoviral p53. Material and Method: Binary adenoviral PTEN and LacZ (Ad/GT-LacZ and Ad/GV16) vectors were used for transduction of the mesothelioma cell lines, REN (p53 sensitive). Protein levels were determined by Western blotting assay. Apoptosis was assessed by fluorescence-activated cell sorter analysis of subdiploid populations. Cell viability was determined with the XTT assay. Statistical analysis was performed with analysis of variance and the Student t test. Result: 72 hours after the treatment of adenoviral PTEN gene, cell killing were 32.9% for REN compared to control cell (2.5%) at MOI of 20. Also we observed the over-expression of proapoptotic protein, bax and decreased expression of bcl-2 protein in REN cells. But the expression of BCL-xl, Bak, Bad proteins were not altered. Conclusion: Adenovirus Pten-mediated overexpression of the Bax gene induces apoptosis and decreased cellular viability in p53-sensitive mesothelioma cells. These data suggest that the transfection of PTEN gene may represent a alternative gene therapy strategy to treat mesothelioma.

• Radiation Oncology Journal
• /
• v.17 no.1
• /
• pp.70-77
• /
• 1999

Purpose : The expression of p53, P211WAF/CIP, Bcl-2, and Bax underlying the radiation-induced apoptosis in different pH environments using SCK mammary adenocarcinoma cell line was investigated. Materials and Methods Mammary adenocarcinoma cells of hi) mice (SCK cells) in exponential growth phase were irradiated with a linear accelerator at room temperature. The cells were irradiated with 12 Gy and one hour later, the media was replaced with fresh media at a different pHs. After Incubation at 37Microbioiogy, College of Medicine Dong A University for 0$\~$48 h, the extort of apoptosis was determined using agarose gel electrophoresis and flow cytometry. The progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Western blot analysis was used to monitor p53, p211WAFfCIP, Bcl-2, and Bu protein levels. Results : The induction of apoptosis by irradiation in pH 6.6 medium was markedly less than that in pH 7.5 medium. The radiation-induced G2IM arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Considerable amounts of p53 and p21 proteins already existed at pH 7.5 and increased the level of p53 and p21 significantly after 12 Gy X-irradiation. An incubation at pH 6.6 after 12 Gy X-irradiation did not change the level of p53 and p21 protein levels significantly. Bcl-2 proteins were not significantly affected by radiation and showed no correlation with cell susceptibility to radiation-induced apoptosis in different pHs. An exposure to 12 Gy of X-rays increased the level of Bax protein at pH 7.5 but at pH 6.6, it was slight. Conclusions : The molecular mechanism underlying radiation-induced apoptosis in dinerent pH environments using SCK mammary adenocarcinoma cell line was dependent of the expression p53 and P211YVAF/CIP proteins. We may propose following hypothesis that an acidic stress augments the radiation-induced G2iM arrest, which inhibiting the irradiated cells undergo post-mitotic apoptosis. The effects of environmental acidity on anti-apoptotic and pro-apoptotic function of Bcl-2 family was unclear in SCK mammary adenocarcinoma cell line.

• Applied Microscopy
• /
• v.40 no.4
• /
• pp.229-235
• /
• 2010

Cervical cancer is associated with low antioxidant status. It has a high prevalence especially amongst woman in Asia and is a leading cause of cancer death. Cancer chemotherapy in vivo improved in cases with high p53 expression in the tumor tissue. The restoration of p53 levels could be a potential strategy to increase chemoresponsiveness. Under circumstances where damage is extensive, p53 plays a direct role in trigering apoptosis. To investigate the effect of curcumin (CMN) as an antioxidant agent on anticancer agent 5-fluorouracil (5FU) induced apoptosis and p53 expression, HPV-18 positive HeLa cells were treated with noncytotoxic amounts of antioxidant. Curcumin induced apoptosis in cervical cancer cells. Morphological hallmarks of apoptosis such as nuclear fragmentation and internucleosomal fragmentation of DNA were observed. CMN caused upregulation of p53 expression, evident from Western blotting data and also increased the susceptibility/apoptosis induced by 5FU. These results show that increasing drug sensitivity of cervical cancer cells by upregulation of p53 using CMN is novel approach and could have a possible therapeutic potential in cervical cancer.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2000.12a
• /
• pp.39-43
• /
• 2000

HBV는 인체에 감염하여 간염, 간경변 및 간암을 유발하는 hepadnaviruses의 일종으로써 임상적으로 매우 중요한 바이러스이다. 그러나 이 바이러스에 의한 간암(HCC)의 발생 메커니즘은 아직 불확실하다. 최근에는 HBV의 X 단백질(HBx)이 간암 발생에 중요한 역할을 수행하는 것으로 보고되고 있다. HBx 단백질은 전사 활성인자(transcriptional activator)로써 숙주세포의 유전자발현에 영향을 미치어 세포증식 및 분화에 영향을 줄 수 있다. 본 연구에서는 HBx 단백질이 NIH 3T3 cell의 증식 및 형질전환에 미치는 영향을 조사하였다. HBx 단백질을 발현하는 세포주는 정상세포에 비하여 증식 속도가 2배 정도 빠르며, soft agar assay 결과에 의하면 대조군과 비교하여 더 많은 수의 colony를 형성하였다. 또한, 이들 HBx 발현 세포들은 접촉 저해 능력을 상실하여 HBx가 세포 형질 전환 능력을 가짐을 알수 있다 또한 HBx 발현 세포주에 있어서 p21의 RNA 및 protein수준이 정상세포에 비하여 낮으므로 HBx에 의한 증식 촉진 및 세포 형질 전환이 p21을 매개하여 이루어 짐을 알 수 있었다. HBx에 의한 p21 유전자의 발현 감소는 p21의 전사 수준에서 이루어지며 이는 p53-비의존적 경로에 의하여 이루어졌다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.533-536
• /
• 2019

Recombinant baculoviruses are widely used to express heterologous genes in cultured insect cells. Recombinant baculoviruses can serve as gene-transfer vectors for expression of recombinant proteins in a wide range of mammalian cell types. Baculovirus system has significant benefits in view of safety, large-scale, and high level of gene expression. In this study, baculoviral vectors which were reconstructed from pOPINEneo-3C-GFP vector, were recombined with cytomegalovirus (CMV) promoter, green fluorescent protein (GFP), and p53 with NcoI and XhoI. These recombinant vectors were infected with various cells and cell lines. The baculovirus vector thus developed was analyzed by comparing the metastasis and expression of the recombinant genes with conventional vectors. These results suggest that the baculovirus vector has higher efficiency in metastasis and expression than the control vector. This work was supported by a grant from Mid-Career Researcher Program(NRF-2016R1A2B4016552) through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(MSIP).

• Korean Journal of Clinical Laboratory Science
• /
• v.52 no.1
• /
• pp.69-77
• /
• 2020

The tumor suppressor gene, p53, is inactivated in the human hepatocellular carcinoma cells line, Hep3B. Berberine has been reported to inhibit the proliferation of cancer cells. This study examined whether apoptosis was induced in berberine-treated Hep3B cells and observed the association between apoptosis and the expression of p53 and DNA methyltransferase (DNMT). The cell viability was measured using an MTT assay. Apoptosis of Hep3B was measured using annexin V flow cytometry. Berberine-treated cells were examined for their DNMT enzymatic activity, mRNA expression, and protein synthesis. The p53 levels were examined by Western blot analysis. The berberine treatment resulted in increased Hep3B cell death and apoptosis in a time- and dose-dependent manner. The DNMT3b activity, mRNA expression, and protein levels all decreased after the berberine treatment. In contrast, the p53 protein levels increased with a concomitant decrease in DNMT3b. No change in the expression of ERK was observed, but the P-ERK levels decreased in a dose dependent manner. These results indicate that a treatment of Hep3B cells with berberine can reduce the expression of DNMT3b, leading to an increase in the tumor suppressant gene p53 and an increase in cell apoptosis. This shows that berberine can effectively suppress the proliferation of liver cancer cells.