• Genomics & Informatics
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• v.19 no.1
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• pp.2.1-2.10
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• 2021

BRAF inhibitors (e.g., vemurafenib) are widely used to treat metastatic melanoma with the BRAF V600E mutation. The initial response is often dramatic, but treatment resistance leads to disease progression in the majority of cases. Although secondary mutations in the mitogen-activated protein kinase signaling pathway are known to be responsible for this phenomenon, the molecular mechanisms governing acquired resistance are not known in more than half of patients. Here we report a genome- and transcriptome-wide study investigating the molecular mechanisms of acquired resistance to BRAF inhibitors. A microfluidic chip with a concentration gradient of vemurafenib was utilized to rapidly obtain therapy-resistant clones from two melanoma cell lines with the BRAF V600E mutation (A375 and SK-MEL-28). Exome and transcriptome data were produced from 13 resistant clones and analyzed to identify secondary mutations and gene expression changes. Various mechanisms, including phenotype switching and metabolic reprogramming, have been determined to contribute to resistance development differently for each clone. The roles of microphthalmia-associated transcription factor, the master transcription factor in melanocyte differentiation/dedifferentiation, were highlighted in terms of phenotype switching. Our study provides an omics-based comprehensive overview of the molecular mechanisms governing acquired resistance to BRAF inhibitor therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3437-3445
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• 2016

Background: There is an increasing concern in the role of microRNA (miRNA) in the pathogenesis of bone metastasis (BM) secondary to prostate cancer (CaP). In this exploratory study, we hypothesized that the expression of vinculin (VCL) and chemokine X3C ligand 1 (CX3CL1) might be down-regulated in clinical samples, most likely due to the post-transcriptional modification by microRNAs. Targeted genes would be up-regulated upon transfection of the bone metastatic prostate cancer cell line, PC3, with specific microRNA inhibitors. Materials and Methods: MicroRNA software predicted that miR-21 targets VCL while miR-29a targets CX3CL1. Twenty benign prostatic hyperplasia (BPH) and 16 high grade CaP formalin-fixed paraffin embedded (FFPE) specimens were analysed. From the bone scan results, high grade CaP samples were further classified into CaP with no BM and CaP with BM. Transient transfection with respective microRNA inhibitors was done in both RWPE-1 (normal) and PC3 cell lines. QPCR was performed in all FFPE samples and transfected cell lines to measure VCL and CX3CL1 levels. Results: QPCR confirmed that VCL messenger RNA (mRNA) was significantly down-regulated while CX3CL1 was up-regulated in all FFPE specimens. Transient transfection with microRNA inhibitors in PC3 cells followed by qPCR of the targeted genes showed that VCL mRNA was significantly upregulated while CX3CL1 mRNA was significantly down-regulated compared to the RWPE-1 case. Conclusions: The down-regulation of VCL in FFPE specimens is most likely regulated by miR-21 based on the in vitro evidence but the exact mechanism of how miR-21 can regulate VCL is unclear. Up-regulated in CaP, CX3CL1 was found not regulated by miR-29a. More microRNA screening is required to understand the regulation of this chemokine in CaP with bone metastasis. Understanding miRNA-mRNA interactions may provide additional knowledge for individualized study of cancers.

• Journal of Chest Surgery
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• v.37 no.3
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• pp.261-266
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• 2004

Although significant progress has been made in the surgical treatment of esophageal carcinoma as well as in the detection of early stage esophageal carcinoma by diagnostic techniques, the prognosis of the esophageal carcinoma patients remain poor. The p53 gene product is known to regulate cell growth and proliferation. And the nm23 gene was identified originally as an anti-metastatic influence whose expression was correlated inversely with tumor metastatic potential in murine melanoma cell lines. This experiment was intended to know the relationship among the p53 and nm23 gene expression versus clinicopahologic characteristics of the esophageal cancer. Total 40 cases were collected from patients who had undergone esophagectomy at St. Mary's Hospital, Catholic university of Korea. Immunohistochemical stain for p53 mutant-type protein and nm23 protein was graded as <10% positive tumor cells: negative; 10∼30% positive tumor cells: ＋ ; 30∼50% positive tumor cells: ＋＋, and >50% positive tumor cells: ＋＋＋. The tumor invasion was grades as none:－ ; mild:＋ ; moderate:＋＋ ; severe: ＋＋＋. Overexpression of p53 protein and nm23 was not associated with the survival and cliniocopathologic characteristics of the esophageal cancer. Moreover, the combination analysis of p53 and nm23 revealed that there was no relationship between the gene expression and the clinicopatholic characteristics of the esophageal cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8595-8601
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• 2014

Background: miR-200a expression is frequently altered in numerous cancers. The aim of the present study was to determine the role of microRNA-200a in advanced ovarian carcinomas. Materials and Methods: We measured miR-200a expression in 72 matched normal ovarian tissues and advanced ovarian carcinomas, and also two ovarian carcinoma cell lines (SKOV3 and SKOV3.ip1 - the latter being more invasive and metastatic than the parental SKOV3) by stem-loop real-time RT-PCR based on TaqMan microRNA assay using U6 as a reference. Levels of miR-200a expression were compared by disease stage, tumor grade, histology, and lymph node involvement. To evaluate the role of microRNA-200a, cell proliferation and invasion of SKOV-3 and SKOV-3.ip1 were analyzed with miR-200a inhibitor/mimic transfected cells. Results: Of 72 paired samples, 65 cancer tissues overexpressed microRNA-200a greater than two fold in comparison with matched normal epithelium. Specifically, patients with lymph node metastasis showed significant elevation. The level correlated with clinicopathological features, including high tumor grade, late disease stage, most notably with lymph node metastasis, but not with tumor histology. In addition, SKOV-3.ip1 cells also overexpressed miR-200a compared with SKOV-3, and miR-200a inhibitor transfected SKOV-3.ip1 cells showed significant reduction in cellular proliferation and invasion, while a miR-200a mimic stimulated the opposite behavior. Conclusions: We provide definitive evidence that miR-200a is up-regulated in a significant proportion of advanced ovarian carcinomas, and that elevated miR-200a expression facilitates tumor progression. Our findings support the notion that miR-200a is an onco-microRNA for ovarian cancer, and elevation is a useful potential diagnostic indicator. This study also provides a solid basis for further functional analysis of miR-200a in advanced ovarian cancer.

• IMMUNE NETWORK
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• v.1 no.1
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• pp.36-44
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• 2001

Background : Peritoneal metastasis is one of the maj or types of the stomach cancer recurrence and the role of the adhesion molecules is thought to be very much important in this event. Retinoic acid (RA) has been known to induce the growth inhibition and differentiation of various malignancies, and apoptpsis and the change of expression of adhesion molecules have been reported to be involved in the action of RA. Methods : We studied the adhesion abilities of SNU-1, SNU-5, and SNU-6 cells to the peritoneal endothelial cells as well as the expression of the adhesion molecules (CD44, ICAM-1) in Western blot analysis. And also we studied the expression of apoptosis and the change of expression patterns of the various isoforms of CD44 and the change of the adhsion abilities of the cell line cells after RA treatment. Results: CD44 was expressed in SNU-5 and -16, together with an isoform in SNU-16. ICAM-1 was not expressed in any of the cell line cells tested. After the treatment of RA in the concentration range of $1-5{\times}10^{-5}M$ to three stomach cancer cell lines, growth inhibition, apoptosis and the change of expression of the CD44 were noted. After RA treatment, the expression of CD44H was weakly increased in SNU-1, and was markedly increased in SNU-5. In SNU-16, the expression of CD44H was decreased while that of CD44E were markedly increased. The adhesibility of cells to peritoneal cells was increased in relation with the increase of the CD44H expression, which shows the fact that the adhesibility of tumor cells to peritoneal mesothelial cells is mediated by CD44H recognizing hyaluronic acid. Conclusion : RA induces growth inhibition of stomach cancer cell line cells and increase the adhesiblity of stomach cancer cell line cells to peritoneal mesothelium. It is believed that RA decreases the metastatic ability of stomach cancer cells by upregulating the CD44H expression.

• Journal of Life Science
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• v.25 no.5
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• pp.607-614
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• 2015

Cancers are the largest cause of mortality and morbidity all over the world. Cordycepin, an adenosine analog, is a major functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. Over the last decade, this compound has been reported to possess many pharmacological properties, such as an ability to enhance immune function, as well as anti-inflammatory, antioxidant and anti-cancer effects. Recently, numerous studies have reported interesting properties of cordycepin as a chemopreventive agent as well. There is an accumulating body of experimental evidences suggesting that cordycepin impedes cancer progression by promoting apoptosis, inducing cell cycle arrest, modulating intracellular signaling pathways, and inhibiting invasion and metastasis of cancer cells. In many cancer cell lines, cordycepin inhibits growth and cell cycle progression by inducing arrest of the G2/M phase, resulting from the inhibition of retinoblastoma protein phosphorylation and induction of cyclin-dependent kinase inhibitors. To induce apoptosis, cordycepin activates the extrinsic and intrinsic pathways, which promotes reactive oxygen species generation and the downstream activation of kinase cascades. Cordycepin also can activate alternative pathways to cell death such autophagy. In addition, cordycepin can inhibit the pro-metastatic processes of cancer cell detachment, migration, and invasion through a variety of mechanisms, including the nuclear factor-kappa B and activated protein-1 signaling pathways. In this review, we summarized the variety of action mechanisms by which cordycepin may mediate chemopreventive effects on cancer and discussed the potential of this natural product as a promising therapeutic inhibitor of cancer development.

• Korean Journal of Head & Neck Oncology
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• v.30 no.2
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• pp.53-61
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• 2014

Background and Objectives : Anaplastic thyroid carcinoma(ATC) is a rare but highly aggressive thyroid malignancy that is associated with an extremely poor survival despite the best multidisciplinary care. BRAF(V600E) mutation is detected in about a quarter of ATC, but unlike its high treatment response to selective BRAF inhibitor (PLX4032) in metastatic melanoma, the treatment response of ATC is reported to be low. The purpose of this study is to investigate the innate resistance mechanism responsible for this low treatment response to BRAF inhibitor and its effect on epithelial-mesenchymal transition(EMT). Materials and Methods : Two ATP cell lines, 8505C and FRO were selected and treated with PLX4032 and its drug sensitivity and effects on cell migration and EMT were examined and compared. Further investigation on the changes in signals responsible for the different treatment response to PLX4032 was carried out and the same experiment was performed on both orthotopic and ectopic xenograft mouse models. Results : FRO cell line was more sensitive to PLX4032 treatment compared to 8505C cell line. The resistance to BRAF inhibition in 8505C was due to increased expression of EGFR. Effective inhibition of both EGFR and p-AKT was achieved after dual treatment with BRAF inhibitor(PLX4032) and EGFR inhibitor(Erlotinib). Similar results were confirmed on in vivo study. Conclusion : EGFR-mediated reactivation of the PI3K/AKT pathway and MAPK pathway contributes to the relative insensitivity of BRAF(V600E) mutant ATC cells to PLX4032. Dual inhibition of BRAF and EGFR leads to sustained treatment response including cell invasiveness.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3311-3317
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• 2014

Background: The consequence of Rho GDP dissociation inhibitor alpha (RhoGDI${\alpha}$) activity on migration and invasion of estrogen receptor positive ($ER^+$) and negative ($ER^-$) breast cancer cells has not been studied using the proteomic approach. Changes in expression of RhoGDI${\alpha}$ and other proteins interacting directly or indirectly with RhoGDI${\alpha}$ in MCF7 and MDA-MB-231, with different metastatic potentials is of particular interest. Materials and Methods: $ER^+$ MCF7 and ER- MDA-MB-231 cell lines were subjected to two-dimensional electrophoresis (2-DE) and spots of interest were identified by matrix-assisted laser desorption/ionization time of- flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry (MS) analysis after downregulation of RhoGDI${\alpha}$ using short interfering RNA (siRNA) and upregulated using GFP-tagged ORF clone of RhoGDI${\alpha}$. Results: The results showed a total of 35 proteins that were either up- or down-regulated in these cells. Here we identifed 9 and 15 proteins differentially expressed with silencing of RhoGDI${\alpha}$ in MCF-7 and the MDA-MB-231 cells, respectively. In addition, 10 proteins were differentially expressed in the upregulation of RhoGDI${\alpha}$ in MCF7, while only one protein was identified in the upregulation of RhoGDI${\alpha}$ in MDA-MB-231. Based on the biological functions of these proteins, the results revealed that proteins involved in cell migration are more strongly altered with RhoGDI-${\alpha}$ activity. Although several of these proteins have been previously indicated in tumorigenesis and invasiveness of breast cancer cells, some ohave not been previously reported to be involved in breast cancer migration. Hence, these proteins may serve as useful candidate biomarkers for tumorigenesis and invasiveness of breast cancer cells. Conclusions: Future studies are needed to determine the mechanisms by which these proteins regulate cell migration. The combination of RhoGDI${\alpha}$ with other potential biomarkers may be a more promising approach in the inhibition of breast cancer cell migration.

• Journal of Life Science
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• v.21 no.4
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• pp.529-533
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• 2011

Metallothioneins (MT) are a group of low-molecular weight, cysteine-rich, intracellular proteins that are encoded by a family of genes containing at least 10 functional isoforms in human. The expression and induction of these proteins is associated with protection against DNA damage, oxidative stress, and apoptosis. Many studies have shown increased expression of MT in various human tumors, whereas MT is down-regulated in certain tumors such as hepatocellular carcinoma and liver adenocarcinoma. Hence, the expression of MT is not universal to all human tumors but may depend on the differentiation status and proliferative index of tumors, along with other tissue factors and gene mutations. Using Northern blot analysis, we found that laminin induced expression of MT-1 in HSG and PC12 cells, which can be differentiated by laminin, but had no effect on MB-231, MDA-435, and PC-3 cells, which cannot be differentiated by laminin. In addition, we analyzed the expression level of the MT-1 gene in five prostate cancer cell lines possessing different metastatic potential. The expression of MT-1 in normal and less malignant cells (RWPE-1 and WPE1-NA22) was high and up-regulated by laminin, whereas the expression of MT-1 in WPE1-NB14, WPE1-NB11, and WPE1-NB26 cells (malignant) was extremely low and not elevated by laminin. These results suggest that the MT-1 gene is involved in laminin-mediated differentiation and affects the metastatic potential of tumor cells.

• Korean Journal of Pharmacognosy
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• v.40 no.3
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• pp.205-212
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• 2009

Antitumor activity of Korean mistletoe extract (KM-110) and European commercial mistletoe preparation (Helixor) was investigated. KM-110 showed the cytotoxic effect that it is high for various tumor cell lines and normal splenocytes in comparison with Helixor. Administration of two mistletoe extracts ($100{\mu}g$) to mice did not show any significant changes on the level of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvate transaminase (GTP), blood creatinine (CRE) and blood urea nitrogen (BUN) in sera. The culture supernatant of macrophages stimulated with KM-110 inhibited effectively tumor growth whereas Helixor had little effect. Administration of KM-110 or Helixor resulted in a effective inhibition of lung metastasis after the i.v. inoculation of colon 26-M3.1 lung carcinoma, B16-BL6 melanoma and L5178Y-ML25 lymphomas. In all cases, the mice treated with KM-110 showed more effective anti-tumor metastatic activity than the mice of Helixor. These results suggest that Korean mistletoe extracts, KM-110 might be used as an alternative methods having antitumor activity like European mistletoe preparation, Helixor.