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PubMed | Research Institute and Hospital, Biomolecular Function Research Branch and National Cancer Center
Type: Journal Article | Journal: Oncotarget | Year: 2016

The neuregulin 1 (NRG1) fusion is a recently identified novel driver oncogene in invasive mucinous adenocarcinoma of the lung (IMA). After identification of a case of SLC3A2-NRG1 in a patient with IMA, we verified this fusion gene in a cohort of 59 patients with IMA. Targeted cancer panel sequencing and RT-PCR identified the possible coexistence of other driver oncogenes. Among 59 IMAs, we found 16 NRG1 fusions (13 SLC3A2-NRG1 and 3 CD74-NRG1). Of 16 patients with NRG1 fusions, concurrent KRAS codon 12 mutations were found in 10 cases. We also found concurrent NRAS Q61L mutation and EML4-ALK fusion in additional two cases with NRG1 fusions. When comparing overall survival (OS) according to the presence of NRG1 fusions showed that patients harboring NRG1 fusions had significantly inferior OS than those without NRG1 fusions (hazard ratio = 0.286; 95% confidence interval, .094 to .865). Ectopic expression of the SLC3A2-NRG1 fusion in lung cancer cells increased cell migration, proliferation and tumor growth in vitro and in xenograft models, suggesting oncogenic function for the fusion protein. We found that the SLC3A2-NRG1 fusion promoted ERBB2-ERBB3 phosphorylation and heteroduplex formation and activated the downstream PI3K/AKT/mTOR pathway through paracrine signaling. These findings suggested that the SLC3A2-NRG1 fusion was a driver in IMA with an important prognostic impact. SLC3A2-NRG1 should be considered a therapeutic target for patients with IMA.

PubMed | Ajou University, Chungnam National University and Biomolecular Function Research Branch
Type: Journal Article | Journal: Carcinogenesis | Year: 2015

Several clinical studies have reported increased expression of osteopontin (OPN) in various types of human cancer, including gastric cancer. However, the precise mechanisms underlying tumor development remain unclear. In the present study, we investigated the pathogenic roles of OPN in Helicobacter pylori-induced gastric cancer development. Wild-type (WT) and OPN knockout (KO) mice were treated with N-methyl-N-nitrosourea (MNU) and infected with H.pylori. Mice were killed 50 weeks after treatment, and stomach tissues were assessed by histopathological examination, immunohistochemistry, quantitative real-time RT-PCR and western blotting. To clarify the carcinogenic effects of OPN, we also conducted an in vitro study using AGS human gastric cancer cell line and THP-1 human monocytic cell line. The overall incidence of gastric tumors was significantly decreased in OPN KO mice compared with WT mice. Apoptotic cell death was significantly enhanced in OPN KO mice and was accompanied by upregulation of signal transducer and activator of transcription 1 (STAT1) and inducible nitric oxide synthase (iNOS). In vitro study, OPN suppression also caused STAT1 upregulation and iNOS overexpression in AGS and THP-1 cells, which resulted in apoptosis of AGS cells. In addition, a negative correlation was clearly identified between expression of OPN and iNOS in human gastric cancer tissues. Our data demonstrate that loss of OPN decreases H.pylori-induced gastric carcinogenesis by suppressing proinflammatory immune response and augmenting STAT1 and iNOS-mediated apoptosis of gastric epithelial cells. An important implication of these findings is that OPN actually contributes to the development of gastric cancer.

PubMed | Chungnam National University, Biomolecular Function Research Branch and Seoul National University
Type: Journal Article | Journal: Oncotarget | Year: 2016

Previous clinical reports have found elevated osteopontin (OPN) levels in tumor tissues to be indicative of greater malignancy in human hepatocellular carcinoma (HCC). However, the role of OPN on carcinogenesis and its underlying mechanism remain unclear. In the present study, we investigated the oncogenic role of OPN in diethylnitrosamine (DEN)-induced hepatic carcinogenesis in mice. The overall incidence of hepatic tumors at 36 weeks was significantly lower in OPN knockout (KO) mice than in wild-type (WT) mice. Apoptosis was significantly enhanced in OPN KO mice, and was accompanied by the downregulation of epidermal growth factor receptor (EGFR). In the in vitro study, OPN suppression also led to lower mRNA and protein levels of EGFR associated with the downregulation of c-Jun in Hep3B and Huh7 human HCC cells lines, which resulted in increased apoptotic cell death in both cell lines. Moreover, a positive correlation was clearly identified between the expression of OPN and EGFR in human HCC tissues. These data demonstrate that the OPN deficiency reduced the incidence of chemically induced HCC by suppressing EGFR-mediated anti-apoptotic signaling. An important implication of our findings is that OPN positively contributes to hepatic carcinogenesis.

Jang S.H.,Biomolecular Function Research Branch | Jang S.H.,Seoul National University | Park J.W.,Biomolecular Function Research Branch | Kim H.R.,Biomolecular Function Research Branch | And 2 more authors.
Clinical and Experimental Metastasis | Year: 2014

We searched for candidate target genes in metastatic gastric cancer, using comparative genomic hybridization (CGH) and mRNA expression array analysis of endoscopic biopsy samples collected from 32 patients. Recurrent amplicons included 17q21.2 (36,569,293-37,307,055), 8q24.13-q24.21 (126,357,475-130,159, 285), and 20q13.33 (60,211,249-61,382,787). In this paper, we focused on the 1.1-Mb genomic region containing 24 genes in chromosome 20q13.33 (from 60,211,249 to 61,382,787), the third most frequent amplicon that was amplified in three of 32 patients (9.4 %), with log2 tumor/reference ratios ranging from 0.6 to 1.5. Of three genes in the 20q13.33 amplicon, ADRM1 was chosen for functional analyses. ADRM1 knockdown suppressed the proliferation of two human gastric cancer cells, SNU-601 and SNU-216. Overexpression of Adrm1 promoted cell proliferation of conditionally-immortalized, mouse ImSt gastric epithelial cells, with increased S1 phase fraction and decreased expression of p21(Cip1). These results collectively indicate that ADRM1 promoted gastric epithelial cell proliferation by cell cycle progression. Therefore, ADRM1 is a candidate target gene in the chromosome 20q13.33 amplicon that may possibly be linked to development of gastric cancer. © 2014 Springer Science+Business Media.

Jeong K.-C.,Biomolecular Function Research Branch | Kim K.-T.,National Cancer Center | Seo H.-H.,National Cancer Center | Shin S.-P.,National Cancer Center | And 7 more authors.
Journal of Urology | Year: 2014

Purpose c-MYC is a promising target for cancer therapy but its use is restricted by unwanted, devastating side effects. We explored whether intravesical instillation of the c-MYC inhibitor KSI-3716 could suppress tumor growth in murine orthotopic bladder xenografts. Materials and Methods The small molecule KSI-3716, which blocks c-MYC/MAX binding to target gene promoters, was used as an intravesical chemotherapy agent. KSI-3716 action was assessed by electrophoretic mobility shift assay, chromatin immunoprecipitation, transcription reporter assay and quantitative reverse transcriptase-polymerase chain reaction. Inhibition of cell proliferation and its mechanism was monitored by cell cytotoxicity assay, EdU incorporation assay and flow cytometry. The in vivo efficacy of KSI-3716 was examined by noninvasive luminescence imaging and histological analysis after intravesical instillation of KSI-3716 in murine orthotopic bladder xenografts. Results KSI-3716 blocked c-MYC/MAX from forming a complex with target gene promoters. c-MYC mediated transcriptional activity was inhibited by KSI-3716 at concentrations as low as 1 μM. The expression of c-MYC target genes, such as cyclin D2, CDK4 and hTERT, was markedly decreased. KSI-3716 exerted cytotoxic effects on bladder cancer cells by inducing cell cycle arrest and apoptosis. Intravesical instillation of KSI-3716 at a dose of 5 mg/kg significantly suppressed tumor growth with minimal systemic toxicity. Conclusions The c-MYC inhibitor KSI-3716 could be developed as an effective intravesical chemotherapy agent for bladder cancer.

PubMed | National Cancer Center, Biomolecular Function Research Branch and Center for Breast Cancer
Type: | Journal: Cancer research and treatment : official journal of Korean Cancer Association | Year: 2016

Unclassified variants (UVs) of BRCA1 and BRCA2 genes are not defined as pathogenic for breast cancer, and their clinical significance currently remains undefined. Therefore, this study was conducted to identify potentially pathogenic unclassified variants by comparing their prevalence between breast cancer patients and controls. A total of 328 breast cancer patients underwent BRCA1/2 genetic screening at the National Cancer Center of Korea. Genetic variants of BRCA genes that were categorized as unclassified according to the Breast Cancer Information Core database were selected based on allelic frequency, after which candidate variants were genotyped in 421 healthy controls. We also examined family members of the study participants. Finally, the effects of amino acid substitutions on protein structure and function were predicted in silico.Genetic tests revealed 33 unclassified variants in BRCA1 and 47 in BRCA2. Among 15 candidates genotyped in healthy controls, c.5339T>C in BRCA1 and c.6029T>G, c.7522G>A in BRCA2 were not detected. Moreover, the c.5339T>C variant in the BRCA1 gene was detected in four patients with a family history of breast cancer. This nonsynonymous variant (Leu1780Pro) in the BRCA1 C-terminal (BRCT) domain was predicted to have an effect on BRCA1 protein structure/function. This study showed that comparison of genotype frequency between cases and controls could help identify unclassified variants of BRCA genes that are potentially pathogenic. Moreover, our findings suggest that c.5339T>C in BRCA1 might be a pathogenic variant for patients and their families.

PubMed | Catholic University of Pusan and Biomolecular Function Research Branch
Type: Journal Article | Journal: Journal of structural biology | Year: 2016

Cholesterol-dependent cytolysins (CDCs) contribute to various pathogenesis by Gram-positive bacterial pathogens. Among them, pneumolysin (PLY) produced by Streptococcus pneumoniae is a major contributor to pneumococcal infections. Despite numerous studies of the cytolytic mechanism of PLY, little structural information on its interactions with a specific receptor of the cell membrane is available. We report here the first crystal structures of PLY in an apo-form and in a ternary complex with two mannoses at 2.8 and 2.5 resolutions, respectively. Both structures contained one monomer in an asymmetric unit and were comprised of four discontinuous domains, similar to CDC structures reported previously. The ternary complex structure showed that loop 3 and the undecapeptide region in domain 4 might contribute to cellular recognition by binding to mannose, as a component of a specific cell-surface receptor. Moreover, mutational studies and docking simulations for four residues (Leu431, Trp433, Thr459, and Leu460) in domain 4 indicated that Leu431 and Trp433 in the undecapeptide might be involved in the binding of cholesterol, together with the Thr459-Leu460 pair in loop 1. Our results provide structure-based molecular insights into the interaction of PLY with the target cell membrane, including the binding of mannose and cholesterol.

Choi D.H.,Hanyang University | Park S.J.,Center for Liver Cancer | Kim H.K.,Biomolecular Function Research Branch
Hepatobiliary and Pancreatic Diseases International | Year: 2015

Distinguishing ampullary carcinoma from pancreatic carcinoma is important because of their different prognoses. microRNAs are differentially expressed according to the tissue of origin. However, there is rare research on the differential diagnosis between the two types of cancers by microRNA in periampullary cancers. The present study was undertaken to compare microRNA profiles between ampullary and pancreatic carcinomas using microarrays. miR-215 was most significantly overexpressed in ampullary carcinomas; whereas the expressions of miR-134 and miR-214 were significantly lower in ampullary carcinomas than in pancreatic carcinomas. When these discriminatory microRNAs were applied to liver metastases, they were correctly predicted for the tissue of origin. Although this study is limited by small sample size, striking difference in microRNA expression and concordant expression of discriminating microRNAs in primary tumors and metastases suggest that these novel discriminatory microRNAs warrant future validation. © 2015, Hepatobiliary Pancreat Dis Int. All rights reserved.

Park D.,National Cancer Center | Ahn K.-O.,Biomolecular Function Research Branch | Jeong K.-C.,Biomolecular Function Research Branch | Choi Y.,National Cancer Center
Nanotechnology | Year: 2016

Here, we fabricated polypyrrole nanoparticles (PPys) (termed HA10-PPy, HA20-PPy, and HA40-PPy) doped with different average molecular weight hyaluronic acids (HAs) (10, 20, and 40 kDa, respectively), and evaluated the effect of molecular weight of doped HA on photothermal induction, fluorescence quenching, and drug loading efficiencies. Doxorubicin-loaded HA-doped PPys (DOX@HA-PPys) could be used for imaging and therapy of triple-negative breast cancer (TNBC). Fluorescence turn-on, stimuli-responsive drug release, and photo-induced heating of DOX@HA-PPys enabled not only activatable fluorescence imaging but also subsequent chemo/photothermal dual therapy for TNBC. In particular, we illustrated the potential usefulness of the photothermal effect of the nanoparticles for overcoming chemoresistance in TNBC. © 2016 IOP Publishing Ltd.

PubMed | Biomolecular Function Research Branch and National Cancer Center
Type: | Journal: Oncotarget | Year: 2016

The Hippo signaling pathway plays a crucial role in cell proliferation, apoptosis, differentiation, and development. Major effectors of the Hippo signaling pathway include the transcriptional co-activators Yes-associated protein 1 (YAP) and WW domain-containing transcription regulator protein 1 (TAZ). The transcriptional activities of YAP and TAZ are affected by interactions with proteins from many diverse signaling pathways as well as responses to the external environment. High YAP and TAZ activity has been observed in many cancer types, and functional dysregulation of Hippo signaling enhances the oncogenic properties of YAP and TAZ and promotes cancer development. Many biological elements, including mechanical strain on the cell, cell polarity/adhesion molecules, other signaling pathways (e.g., G-protein-coupled receptor, epidermal growth factor receptor, Wnt, Notch, and transforming growth factor /bone morphogenic protein), and cellular metabolic status, can promote oncogenesis through synergistic association with components of the Hippo signaling pathway. Here, we review the signaling networks that interact with the Hippo signaling pathway and discuss the potential of using drugs that inhibit YAP and TAZ activity for cancer therapy.

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