• The Journal of the Korean Society for Microbiology
• /
• v.35 no.4
• /
• pp.299-308
• /
• 2000

Recently developed cDNA microarray or DNA chip technology allows expression monitoring of expression of hundreds and thousands of genes simultaneously and provides a format for identifying genes as well as changes in their activity. In order to search for changes in gene expression after X irradiation in HL60 cells, cDNA microarray technique was done. In this study, expression of 588 human genes (including oncogenes, tumor suppressor genes, cell cycle regulator genes, intracellular signal transduction modulator genes, apoptosis related genes, transcription factor genes, growth factors and receptor genes, cytokine genes, etc) were analyzed. For cDNA microarray analysis mRNAs were extracted from control and 8 Gy-irradiated HL60 cells. As a result the changes in expression of several genes were observed. This alteration of gene expression was confirmed by reverse transcription-polymerase chain reaction. The expression of heat shock 60 KD protein, c-jun, erythroid differentiation factor, CPP32, myeloid cell nuclear differentiation antigen, MAP kinase-activated protein kinase, interleukin-8, monocyte chemotactic peptide 1 and RANTES genes was increased, but the expression of p55CDC gene was decreased after X irradiation.

• Animal cells and systems
• /
• v.6 no.3
• /
• pp.263-269
• /
• 2002

The p53 tumor suppressor gene is among the most frequently mutated and studied genes in human cancer, but the mechanisms by which it sur presses tumor formation remain unclear. DNA damage regulates both the protein levels of p53 and its affinity for specific DNA sequences. Stabilization of p53 in response to DNA damage is caused by its dissociation from Mdm2, a downstream target gene of p53 and a protein that targets p53 for degradation in the proteosome. Recent studies have suggested that phosphorylation of human p53 at Ser20 is important for stabilizing p53 in response to DNA damage through disruption of the interaction between Mdm2 and p53. We generated mice with an allele encoding changes at Ser20, known to be essential for p53 accumulation following DNA damage, to enable analyses of p53 stabilization in vivo. Our data showed that the mutant p53 was clearly defective for full stabilization of p53 in response to DNA damage. We concluded that Ser20 phosphorylation is critical for modulating the negative regulation of p53 by Mdm2, probably through phosphorylation-dependent inhibition of p53-Mdm2 interaction in the physiological context.

• Molecules and Cells
• /
• v.38 no.6
• /
• pp.548-561
• /
• 2015

By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the $CD31^+$endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-$1^+$ fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.

• The Journal of Korean Medicine
• /
• v.25 no.4
• /
• pp.79-89
• /
• 2004

Saussurea lappa and Taraxacum mongolicum have been used for herbal medicinal treatments against cancers in East Asia. We performed this study to understand the molecular basis underlying the anti-tumor effects of two herbs and analyzed the effects of these medicinal herbs on proliferation and on expression of cell growth/apoptosis related molecules by using an AGS gastric cancer cell line. The treatments of Saussurea lappa dramatically reduced cell viabilities in a dose and time-dependent manner, but Taraxacum mongolicum did not. FACS analysis and Annexin V staining assay also showed that Saussurea lappa induces apoptotic cell death of AGS. Expression analyses via RT-PCR and Western blots revealed that Saussurea lappa increased expression of the p53 and its downstream effector p21/sup Waf1/, and that the both increased expression of apoptosis related Bax and cleavage of active caspase-3 protein. We also confirmed the translocation of Bax to mitochondria Collectively, our data demonstrate that Saussurea lappa induces growth inhibition and apoptosis of human gastric cancer cells, and these effects are correlated with down- and up-regulation of growth-regulating apoptotic and tumor suppressor genes, respectively.

• BMB Reports
• /
• v.36 no.1
• /
• pp.43-48
• /
• 2003

Understanding the process of carcinogenesis will involve both the accumulation of many scientific facts derived from molecular, biochemical, cellular, physiological, whole animal experiments and epidemiological studies, as well as from conceptual understanding as to how to order and integrate those facts. From decades of cancer research, a number of the "hallmarks of cancer" have been identified, as well as their attendant concepts, including oncogenes, tumor suppressor genes, cell cycle biochemistry, hypotheses of metastasis, angiogenesis, etc. While all these "hallmarks" are well known, two important concepts, with their associated scientific observations, have been generally ignored by many in the cancer research field. The objective of the short review is to highlight the concept of the role of human adult pluri-potent stem cells as "target cells" for the carcinogenic process and the concept of the role of gap junctional intercellular communication in the multi-stage, multi-mechanism process of carcinogenesis. With these two concepts, an attempt has been made to integrate the other well-known concepts, such as the multi-stage, multi-mechanisn or the "initiation/promotion/progression" hypothesis; the stem cell theory of carcinogenesis; the oncogene/tumor suppression theory and the mutation/epigenetic theories of carcinogenesis. This new "integrative" theory tries to explain the well-known "hallmarks" of cancers, including the observation that cancer cells lack either heterologous or homologous gap junctional intercellular communication whereas normal human adult stem cells do not have expressed or functional gap junctional intercellular communication. On the other hand, their normal differentiated, non-stem cell derivatives do express connexins and express gap junctional intercellular communication during their differentiation. Examination of the roles of chemical tumor promoters, oncogenes, connexin knock-out mice and roles of genetically-engineered tumor and normal cells with connexin and anti-sense connexin genes, respectively, seems to provide evidence which is consistent with the roles of both stem cells and gap junctional communication playing a major role in carcinogenesis. The integrative hypothesis provides new strategies for chemoprevention and chemotherapy which focuses on modulating connexin gene expression or gap junctional intercellular communication in the premalignant and malignant cells, respectively.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.6
• /
• pp.2719-2725
• /
• 2014

Background: Secreted frizzled-related protein (SFRP) genes, new tumor suppressor genes, are negative regulators of the Wnt pathway whose alteration is associated with various tumors. In ovarian cancer, SFRPs genes promoter methylation can lead to gene inactivation. This study investigated mechanisms of SFRP and adenomatous polyposis coli (APC) genes silencing in ovarian cancer infected with high risk human papillomavirus. Materials and Methods: DNA was extracted from 200 formalin-fixed paraffin-embedded ovarian cancer and their normal adjacent tissues (NAT) and DNA methylation was detected by methylation specific PCR (MSP). High risk human papillomavirus (HPV) was detected by nested PCR with consensus primers to amplify a broad spectrum of HPV genotypes. Results: The percentages of SFRP and APC genes with methylation were significantly higher in ovarian cancer tissues infected with high risk HPV compared to NAT. The methylated studied genes were associated with suppression in their gene expression. Conclusion: This finding highlights the possible role of the high risk HPV virus in ovarian carcinogenesis or in facilitating cancer progression by suppression of SFRP and APC genes via DNA methylation.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.9
• /
• pp.3865-3871
• /
• 2014

It is becoming progressively more understandable that different phytochemicals isolated from edible plants interfere with specific stages of carcinogenesis. Cancer cells have evolved hallmark mechanisms to escape from death. Concordant with this approach, there is a disruption of spatiotemproal behaviour of signaling cascades in cancer cells, which can escape from apoptosis because of downregulation of tumor suppressor genes and over-expression of oncogenes. Genomic instability, intra-tumor heterogeneity, cellular plasticity and metastasizing potential of cancer cells all are related to molecular alterations. Data obtained through in vitro studies has convincingly revealed that curcumin, EGCG, resveratrol and quercetin are promising anticancer agents. Their efficacy has been tested in tumor xenografted mice and considerable experimental findings have stimulated researchers to further improve the bioavailability of these nutraceuticals. We partition this review into different sections with emphasis on how bioavailability of curcumin, EGCG, resveratrol and quercetin has improved using different nanotechnology approaches.

• The Journal of the Korean bone and joint tumor society
• /
• v.6 no.4
• /
• pp.143-151
• /
• 2000

Purpose : The p53 tumor suppressor gene is one of the most frequently altered genes in human malignancies. We try to explore the implication of p53 alteration in Ewing's sarcoma. Materials and Methods : We analyzed 35 paraffin blocks to explore the deletion and sequence alterations of p53. Results : Quantitative PCR analysis showed that 2 tumors showed a homozygous deletion of the gene. Mutational analysis of exons 4 to 9 of p53 by PCR-SSCP revealed that 3 tumors carry sequence alterations in exons 5 or 8, and DNA sequencing analysis identified missense point mutations. Conclusion : Taken together, our data demonstrate that p53 is genetically altered in a small fraction of Ewing's sarcoma.

• The Journal of Internal Korean Medicine
• /
• v.24 no.1
• /
• pp.134-143
• /
• 2003

Objectives : We performed this study to understand the molecular basis of the antitumor effect of Saussurea lappa, Pharbitis nil, Plantago asiatica and Taraxacum mongolicum, which have been used for cancer treatment in Korean traditional medicine. Design: We analyzed, the effect of these medicinal herbs on proliferation and apoptosis of tumor cells and its association with gene expression, We performed semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR) analysis of cell cycle- and apoptosis-related genes using a gastric cancer cell line AGS. Results : Cell counting assay and $[^3H]thymidine$ uptake analysis showed that Saussurea lappa and Pharbitis nil strongly inhibit cell proliferation of AGS in a dose-dependent manner. Interestingly, gene espression assay revealed that mRNA espression levels of c-Jun, c-Fos, c-Myc, and Cyclin D1 were markedly decreased by Saussurea lappa and Pharbitis nil. Furthermore, Saussurea lappa was identified to activate expression of the p53 tumor suppressor and its downstream effector $p21^{Wafl}$, which leads to $G_1$ cell cycle arrest and apoptosis. These observations suggest that the anticancer effect of Saussurea lappa and Pharbitis nil might be associated with their regulatory capability of tumor-related gene expression.

• BMB Reports
• /
• v.54 no.7
• /
• pp.335-343
• /
• 2021

Cancer stem cells (CSCs) are a subpopulation of cancer that can self-renew and differentiate into large tumor masses. Evidence accumulated to date shows that CSCs affect tumor proliferation, recurrence, and resistance to chemotherapy. Recent studies have shown that, like stem cells, CSCs maintain cells with self-renewal capacity by means of asymmetric division and promote cell proliferation by means of symmetric division. This cell division is regulated by fate determinants, such as the NUMB protein, which recently has also been confirmed as a tumor suppressor. Loss of NUMB expression leads to uncontrolled proliferation and amplification of the CSC pool, which promotes the Notch signaling pathway and reduces the expression of the p53 protein. NUMB genes are alternatively spliced to produce six functionally distinct isoforms. An interesting recent discovery is that the protein NUMB isoform produced by alternative splicing of NUMB plays an important role in promoting carcinogenesis. In this review, we summarize the known functions of NUMB and NUMB isoforms related to the proliferation and generation of CSCs.