[Show abstract][Hide abstract] ABSTRACT: The risk of gastrointestinal (GI) bleeding is increased in association with the use of low-dose aspirin (LDA). There are few studies of the association between genetic polymorphisms and the risks of aspirin-induced ulcer or its complications. Individuals with two single nucleotide polymorphisms (SNPs) of cyclooxygenase-1 (COX-1), A-842G and C50T, exhibit increased sensitivity to aspirin and lower prostaglandin synthesis capacity but the polymorphism lacked statistical significance in relation to an association with bleeding peptic ulcer. In our previous Japanese study, SLCO1B1 521TT genotype and the SLCO1B1 *1b haplotype were significantly associated with the risk of peptic ulcer and ulcer bleeding in patients taking LDA, especially in the patients with angiotensin converting enzyme inhibitor (ACEI), angiotensin type 1 receptor blocker (ARB), or statin co-treatment. Proton-pump inhibitors (PPIs) are recommended for patients who require antiplatelet therapy and have a history of upper GI bleeding. The interaction between PPIs and consequent impaired effectiveness of clopidogrel has caused concern regarding the effect of genetic polymorphisms of the CYP2C19 which mediates conversion of clopidogrel to its active metabolite. The later recent genome-wide analysis of SNPs indicated the association of several SNPs with small bowel bleeding in Japanese patients taking LDA. The data are still lacking and further prospective studies are needed to identify the specific gene polymorphisms as risk or protective factors for GI bleeding associated with LDA.
Current pharmaceutical design 09/2015; 21(999). DOI:10.2174/1381612821666150915105537 · 3.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although several molecular biomarkers for esophageal adenocarcinoma (EAC) have been shown to be useful disease indicators, none has been established as a reliable indicator for risk of EAC or have progressed to routine use. The aim was to identify biomarkers of high risk for EAC in patients with Barrett's esophagus (BE).
Following endoscopic observation by magnified endoscopy with narrow band imaging (ME-NBI), brushing was followed by obtaining biopsy samples from columnar-lined esophagus (CLE) and from EAC lesions of EAC patients, and from age- and sex-matched non-EAC controls with BE. Total RNA was extracted for microarray analysis using Affymetrix GeneChip Human Genome U133 plus 2.0 Array. Real-time -PCR analysis of identified candidate genes was used to confirm the results.
Overall, 9 EAC patients and 50 patients with BE were studied. Seventy-nine candidate genes were identified by microarray analysis based on a proportional hazards model (P <0.005). Six genes exhibited significantly differential expressions in both BE and cancer lesions of the EAC group compared to BE of the controls. In the brushing samples, median CD55 relative expression levels in cancer lesions were highest and decreased in BE of EAC group and BE of the controls, in that order (p <0.001).
Over expression of CD55 in brushing samples taken from BE may be associated with the risk of EAC.
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Journal of Gastroenterology and Hepatology 07/2015; DOI:10.1111/jgh.13055 · 3.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Since the prognosis of unresectable advanced gastric cancer remains poor, novel therapeutic strategies are needed. Somatic MEK1 gene mutations have been reported as oncogenic activating mutations in gastric cancer, and MEK inhibitors can be effective against such gastric cancers. In the present study, however, activated EGFR and HER2 signals after treatment with a MEK inhibitor (trametinib) were found in a MEK1-mutated gastric cancer cell line (OCUM-1 cell line) using a phospho-receptor tyrosine kinase array. The phosphorylation of EGFR and HER2 reactivated ERK1/2, which had been inhibited by trametinib, and EGF stimulation led to resistance to trametinib in this cell line. Lapatinib, an EGFR and an HER2 inhibitor, reversed the activation of ERK1/2 by inhibiting the phosphorylation of EGFR and HER2 and cancelled the resistance. The combination of trametinib and lapatinib synergistically inhibited the cell growth of the OCUM-1 cell line and strongly induced apoptosis by inhibiting the activated EGFR and HER2 signals. These results suggest that the EGFR and HER2 signals play a salvage role and are related to resistance to MEK inhibitors in MEK1‑mutated gastric cancer. Moreover, combination therapy with trametinib and lapatinib can exhibit a synergistic effect and may contribute to overcoming the resistance to MEK inhibitors.
International Journal of Oncology 06/2015; 47(2). DOI:10.3892/ijo.2015.3050 · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Somatic mutations in KRAS, NRAS, and BRAF genes are related to resistance to anti-EGFR antibodies in colorectal cancer. We have established an extended RAS and BRAF mutation assay using a next-generation sequencer to analyze these mutations. Multiplexed deep sequencing was performed to detect somatic mutations within KRAS, NRAS, and BRAF, including minor mutated components. We first validated the technical performance of the multiplexed deep sequencing using 10 normal DNA and 20 formalin-fixed, paraffin-embedded (FFPE) tumor samples. To demonstrate the potential clinical utility of our assay, we profiled 100 FFPE tumor samples and 15 plasma samples obtained from colorectal cancer patients. We used a variant calling approach based on a Poisson distribution. The distribution of the mutation-positive population was hypothesized to follow a Poisson distribution, and a mutation-positive status was defined as a value greater than the significance level of the error rate (α = 2 x 10(-5)). The cut-off value was determined to be the average error rate plus 7 standard deviations. Mutation analysis of 100 clinical FFPE tumor specimens was performed without any invalid cases. Mutations were detected at a frequency of 59% (59/100). KRAS mutation concordance between this assay and Scorpion-ARMS was 92% (92/100). DNA obtained from 15 plasma samples was also analyzed. KRAS and BRAF mutations were identified in both the plasma and tissue samples of 6 patients. The genetic screening assay using next-generation sequencer was validated for the detection of clinically relevant RAS and BRAF mutations using FFPE and liquid samples.
PLoS ONE 05/2015; 10(5):e0121891. DOI:10.1371/journal.pone.0121891 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Various alterations underlying acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have been described. Although treatment strategies specific for these mechanisms are under development, cytotoxic agents are currently employed to treat many patients following failure of EGFR-TKIs. However, the effect of TKI resistance on sensitivity to these cytotoxic agents is mostly unclear. This study investigated the sensitivity of erlotinib-resistant tumor cells to five cytotoxic agents using an in vitro EGFR-TKI-resistant model. Four erlotinib-sensitive lung adenocarcinoma cell lines and their resistant derivatives were tested. Of the resistant cell lines, all but one showed a similar sensitivity to the tested drugs as their parental cells. HCC4006ER cells with epithelial mesenchymal transition features acquired resistance to the three microtubule-targeting agents, docetaxel, paclitaxel and vinorelbine, but not to cisplatin and gemcitabine. Gene expression array and immunoblotting demonstrated that ATP-binding cassette subfamily B, member 1 (ABCB1) was up-regulated in HCC4006ER cells. ABCB1 knockdown by siRNA partially restored sensitivity to the anti-microtubule agents but not to erlotinib. Moreover, the histone deacetylase inhibitor entinostat sensitized HCC4006ER cells to anti-microtubule agents through ABCB1 suppression. Our study indicates that sensitivity of tumor cells to cytotoxic agents in general does not change before and after failure of EGFR-TKIs. However, we describe that two different molecular alterations confer acquired resistance to EGFR-TKIs and cytotoxic agents, respectively. This phenomenon should be kept in mind in selection of subsequent therapy after failure of EGFR-TKIs.
PLoS ONE 04/2015; 10(4):e0123901. DOI:10.1371/journal.pone.0123901 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We compared the performance of the 3D-Gene® mutation assay (3D-Gene® KRAS mutation assay kit) with the Scorpion-ARMS (therascreen® KRAS RGQ PCR Kit) and Luminex (MEBGEN™ KRAS kit) assays for the detection of KRAS mutations in formalin-fixed, paraffin-embedded tissue samples from 150 patients diagnosed with colorectal cancer. DNA was extracted from the paraffin-embedded tissue samples with or without macrodissection under hematoxylin and eosin staining and the KRAS mutation status was independently determined using these assays. Discordant results were re-analyzed by Sanger sequencing. Mutation detection analysis was successfully performed in all 150 specimens using the 3D-Gene® mutation assay without an invalid case. The concordance rate between the 3D-Gene® mutation assay and Scorpion-ARMS or Luminex was 98.7% (148/150). KRAS mutations were detected at a frequency of 35.3% (53/150) in colorectal cancer specimens. Three discrepant cases were found between the three assays. Overall, our results demonstrate a high concordance rate of between the 3D-Gene® mutation assay and the two existing in-vitro diagnostics kits. All three assays proved to be validated methods for detecting clinically significant KRAS mutations in paraffin-embedded tissue samples.
Electronic supplementary material
The online version of this article (doi:10.1186/2193-1801-4-7) contains supplementary material, which is available to authorized users.
[Show abstract][Hide abstract] ABSTRACT: Non-small cell lung cancer (NSCLC) carrying echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) rearrangements is hypersensitive to ALK inhibitors, including crizotinib and alectinib. Crizotinib was initially designed as a MET inhibitor, whereas alectinib is a selective ALK inhibitor. The MET signal, which is inhibited by crizotinib but not by alectinib, is dysregulated in many human cancers. However, the role of the MET signal in ALK-positive NSCLC remains unclear. In this study, we found that hepatocyte growth factor (HGF), ligand of MET, mediated the resistance to alectinib, but not to crizotinib, via the MET signal in ALK-positive NSCLC cell lines (H3122 and H2228 cell lines). In addition, alectinib activated the MET signal even in the absence of HGF and the inhibition of the MET signal enhanced the efficacy of alectinib. These findings suggest that activated MET acts as a salvage signal in ALK-positive NSCLC. This novel role of the MET signal in ALK-positive NSCLC may pave the way for further clinical trials examining MET inhibitors.
International Journal of Oncology 12/2014; 46(3). DOI:10.3892/ijo.2014.2797 · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The prognosis for patients with unresectable advanced or recurrent gastric cancer remains poor. The identification of additional oncogenes with influences similar to those of epidermal growth factor receptor gene mutations, upon which the growth of cancer cells is dependent, is needed. In this study, we evaluated sensitivity to MEK inhibitors (GSK1120212 and PD0325901) in several gastric cancer cell lines in vitro and found three poorly differentiated gastric cancer cell lines that were hypersensitive to the inhibitors. The sequence analyses in these three cell lines revealed that one cell line had a novel MEK1 mutation, while the other two had previously reported KRAS and MEK1 mutations, respectively; the gene statuses of the other resistant cell lines were all wild-type. Experiments using MEK1 expression vectors demonstrated that the MEK1 mutations induced the phosphorylation of ERK1/2 and had a transforming potential, enhancing the tumorigenicity. The MEK inhibitor dramatically reduced the phosphorylation of ERK1/2 and induced apoptosis in the cell lines with MEK1 mutations. In vivo, tumor growth was also dramatically decreased by an inhibitor. One of the 46 gastric cancer clinical samples that were examined had a MEK1 mutation; this tumor had a poorly differentiated histology. Considering the addiction of cancer cells to active MEK1 mutations for proliferation, gastric cancer with such oncogenic MEK1 mutations might be suitable for targeted therapy with MEK inhibitors.
Molecular Cancer Therapeutics 12/2014; 13(12):3098-3106. DOI:10.1158/1535-7163.MCT-14-0429 · 5.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction:
Patients with non-small-cell lung cancer (NSCLC) with somatic activating mutations of the epidermal growth factor receptor gene (EGFR mutations) generally respond to EGFR tyrosine kinase inhibitors (EGFR-TKIs). β-Catenin is a key component of the Wnt/β-Catenin signal and is an important oncogene that is involved in the pathogenesis and progression of malignant tumors, especially cancer stem cells.
Methods and results:
We found that EGFR-mutated NSCLC cell lines exhibited a high expression level of β-Catenin, compared with cell lines with the wild-type EGFR gene, and XAV939 (a β-Catenin inhibitor) enhanced the sensitivities to EGFR-TKI in EGFR-mutated NSCLC cell lines. In EGFR-mutated NSCLC cell lines with the acquired resistance threonine-to-methionine mutation in codon 790 (T790M) mutation, XAV939 enhanced the sensitivity of the cells to an irreversible EGFR-TKI but not a reversible EGFR-TKI. The combination of XAV939 and EGFR-TKIs strongly inhibited the β-Catenin signal and strongly decreased the phosphorylation of EGFR, compared with the use of EGFR-TKIs alone, suggesting an interaction between EGFR and the β-Catenin signal. The stem cell-like properties of the EGFR-mutated cell line carrying the T790M mutation were inhibited by XAV939 and BIBW2992 (an irreversible EGFR-TKI). Furthermore, the stem cell-like properties were strongly inhibited by a combination of both the agents. A xenograft study demonstrated that β-Catenin knockdown enhanced the antitumor effect of BIBW2992 in the EGFR-mutated NSCLC cell line carrying the T790M mutation.
Our findings indicate that β-Catenin might be a novel therapeutic target in EGFR-mutated NSCLC carrying the T790M mutation.
Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 11/2014; 10(1). DOI:10.1097/JTO.0000000000000353 · 5.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Patients with non-small cell lung cancer (NSCLC) with echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) rearrangements generally respond to ALK inhibitors such as crizotinib. However, some patients with EML4-ALK rearrangements respond poorly to crizotinib. Hypoxia is involved in the resistance to chemotherapeutic treatments in several cancers, and we investigated the association between the responses to ALK inhibitors and hypoxia. Sensitivity of the H3122 NSCLC cell line (EML4-ALK rearrangement) to ALK inhibitors (crizotinib or alectinib) was investigated during a normoxic or hypoxic state using an MTT assay. We found that the cell line was resistant to the inhibitors during hypoxia. Hypoxia mediated morphologic changes, including cell scattering and the elongation of the cell shape, that are characteristic of the epithelial-mesenchymal transition (EMT). A migration assay demonstrated that the number of migrating cells increased significantly during hypoxia, compared with during normoxia. Regarding EMT-related molecules, the expressions of slug, vimentin, and fibronectin were increased while that of E-cadherin was decreased by hypoxia. In addition, hypoxia inducible factor 1A-knockdown cancelled the hypoxia-induced EMT and resistance. Our findings indicate that hypoxia induces resistance to ALK inhibitors in NSCLC with an EML4-ALK rearrangement via the EMT.
International Journal of Oncology 08/2014; 45(4). DOI:10.3892/ijo.2014.2574 · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The KIAA1199 gene was first discovered to be associated with non-syndromic hearing loss. Recently, several reports have shown that the up-regulation of KIAA1199 is associated with cancer cell migration or invasion and a poor prognosis. These findings indicate that KIAA1199 may be a novel target for cancer therapy. Therefore, we explored in detail the function of KIAA1199 in cancer cells. In this study, we investigated the interaction of KIAA1199 protein with intracellular proteins in cancer cells. To this end, we expressed KIAA1199-MBP fusion protein and performed a pull-down assay. In addition, KIAA1199-overexpressing cancer cell lines were constructed using a retroviral vector and were used for further experiments. A pull-down analysis showed that the glycogen phosphorylase kinase β-subunit (PHKB) interacted with the C-terminal region of KIAA1199 protein. Furthermore, we observed the interaction of KIAA1199 with glycogen phosphorylase brain form (PYGB) under serum-free conditions. The interaction promoted glycogen breakdown and cancer cell survival. Our findings indicate that KIAA1199 plays an important role in glycogen breakdown and cancer cell survival and that it may represent a novel target for cancer therapy.
[Show abstract][Hide abstract] ABSTRACT: Chromosomal band 11q13 seems to be one of the most frequently amplified lesions in human cancer, including esophageal squamous cell cancer (ESCC). The oral cancer overexpressed 1 (ORAOV1) gene has been identified within this region, but its detailed biological function in human ESCC remains largely unclear. In our clinical samples of stage III ESCC, ORAOV1 amplification was observed in 49 of 94 cases (53%). ORAOV1 amplification was significantly associated with a poorly differentiated histology and tumors located in the upper or middle esophagus. Patients with ORAOV1 amplification tended to have a shorter survival period, although the difference was not significant. To investigate the function of ORAOV1, we created ORAOV1--overexpressed ESCC cell lines that exhibited increased cellular proliferation and colony formation, compared with in vitro controls. In vivo, ORAOV1-overexpressed cells exhibited a significantly increased tumorigenicity and a significantly larger tumor volume and poorer differentiation than controls. The peptide mass fingerprinting technique demonstrated that ORAOV1 bound to pyrroline-5-carboxylate reductase (PYCR), which is associated with proline metabolism and reactive oxygen species (ROS) production. Then, ORAOV1-overexpressed cell lines were resistant to stress treatment, which was cancelled by PYCR-knockdown. In addition, the ORAOV1-overexpressed cell line had a higher intracellular proline concentration and a lower ROS level. Our findings indicate that the ORAOV1 gene is frequently amplified in ESCC, enhances tumorigenicity and tumor growth, and is associated with a poorly differentiated tumor histology via proline metabolism and ROS production. ORAOV1 could be a novel target for the treatment of ESCC.
[Show abstract][Hide abstract] ABSTRACT: Background
Transforming growth factor, beta (TGFB) signal is considered to be a tumor suppressive pathway based on the frequent genomic deletion of the SMAD4 gene in pancreatic cancer (PC); however; the role of the activin signal, which also belongs to the TGFB superfamily, remains largely unclear.
Methods and results
We found a homozygous deletion of the activin A receptor, type IB (ACVR1B) gene in 2 out of 8 PC cell lines using array-comparative genomic hybridization, and the absence of ACVR1B mRNA and protein expression was confirmed in these 2 cell lines. Activin A stimulation inhibited cellular growth and increased the phosphorylation level of SMAD2 and the expression level of p21CIP1/WAF1 in the Sui66 cell line (wild-type ACVR1B and SMAD4 genes) but not in the Sui68 cell line (homozygous deletion of ACVR1B gene). Stable ACVR1B-knockdown using short hairpin RNA cancelled the effects of activin A on the cellular growth of the PC cell lines. In addition, ACVR1B-knockdown significantly enhanced the cellular growth and colony formation abilities, compared with controls. In a xenograft study, ACVR1B-knockdown resulted in a significantly elevated level of tumorigenesis and a larger tumor volume, compared with the control. Furthermore, in clinical samples, 6 of the 29 PC samples (20.7%) carried a deletion of the ACVR1B gene, while 10 of the 29 samples (34.5%) carried a deletion of the SMAD4 gene. Of note, 5 of the 6 samples with a deletion of the ACVR1B gene also had a deletion of the SMAD4 gene.
We identified a homozygous deletion of the ACVR1B gene in PC cell lines and clinical samples and proposed that the deletion of the ACVR1B gene may mediate an aggressive cancer phenotype in PC. Our findings provide novel insight into the role of the activin signal in PC.
Molecular Cancer 05/2014; 13(1):126. DOI:10.1186/1476-4598-13-126 · 4.26 Impact Factor