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2.
Int J Gynecol Cancer ; 28(3): 428-436, 2018 03.
Article in English | MEDLINE | ID: mdl-29465505

ABSTRACT

BACKGROUND: Mucinous epithelial ovarian cancers (mEOCs) respond poorly to conventional chemotherapy and have a poor prognosis in advanced stages. The genomic landscape for mEOC in the Asian settings is ill defined. We seek to identify various mutational aberrations present in mEOC and correlate them with clinical outcomes. METHODS: A total of 199 cases of mEOC were identified from a prospectively maintained gynecologic oncology tumor database. DNA was extracted and analyzed for KRAS mutations by using Sanger sequencing. Further MassArray sequencing was performed on 45 samples. Clinicopathologic correlation was performed with the results obtained. FINDINGS: KRAS mutation status was evaluable in 124 cases. Fifty-five percent (68/124) were KRAS negative, whereas 45% (56/124) harbored a KRAS mutation, lower than that in Western populations. Successful ascertainment of both KRAS and HER2 statuses by Sanger sequencing occurred for 105 cases. The proportion of the double-positive subtype (HER2+ and KRAS positive) was 8% (8/105); double-negative subtype (HER2- and KRAS negative), 34% (36/105); and cases with mutation in either KRAS or HER2, 58% (61/105). The KRAS mutation rate was 44%, 50%, and 29% among Chinese, Indians, and Malays, respectively. There was no significant difference in overall survival (P = 0.952) or progression-free survival (P = 0.635) between KRAS-positive and KRAS-negative patients. Similar results were observed for progression-free survival (P = 0.206) and overall survival (P = 0.440) when outcomes were examined between the 4 groups based on KRAS and HER2 mutation. Patients in the double-negative mutation subgroup had higher risk for death/progression compared with patients in the other 3 mutation subgroups. Further MassARRAY multiplexed profiling was performed in patients with sufficient DNA material (n = 45) and yielded KRAS mutations (n = 16), PDGFRA mutations (n = 3), PIK3CA (n = 1) and KIT (n = 1), and HRAS, FGFR, MET, and NRAS (n = 1 each). CONCLUSIONS: Our study provides further knowledge about the mutational aberrations in mEOC in Asian populations. Neither the presence of KRAS mutation nor their correlation with HER2 mutations influenced outcomes.


Subject(s)
Adenocarcinoma, Mucinous/genetics , Asian People/genetics , Mutation , Ovarian Neoplasms/genetics , Adenocarcinoma, Mucinous/pathology , Adult , DNA Mutational Analysis , DNA, Neoplasm/genetics , DNA, Neoplasm/isolation & purification , Disease-Free Survival , Female , Humans , Immunohistochemistry , In Situ Hybridization , Middle Aged , Ovarian Neoplasms/pathology , Proto-Oncogene Proteins p21(ras)/genetics , Receptor, ErbB-2/genetics
3.
Cell Oncol (Dordr) ; 39(2): 175-86, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26868260

ABSTRACT

BACKGROUND: Melanoma-associated antigen (MAGE)-A3 is a member of the family of cancer-testis antigens and has been found to be epigenetically regulated and aberrantly expressed in various cancer types. It has also been found that MAGE-A3 expression may correlate with an aggressive clinical course and with chemo-resistance. The objectives of this study were to assess the relationship between MAGE-A3 promoter methylation and expression and (1) gastric cancer patient survival and (2) its functional consequences in gastric cancer-derived cells. METHODS: Samples from two independent gastric cancer cohorts (including matched non-malignant gastric samples) were included in this study. MAGE-A3 methylation and mRNA expression levels were determined by methylation-specific PCR (MSP) and quantitative real-time PCR (qPCR), respectively. MAGE-A3 expression was knocked down in MKN1 gastric cancer-derived cells using miRNAs. In addition, in vitro cell proliferation, colony formation, apoptosis, cell cycle, drug treatment, immunohistochemistry and Western blot assays were performed. RESULTS: Clinical analysis of 223 primary patient-derived samples (ntumor = 161, nnormal = 62) showed a significant inverse correlation between MAGE-A3 promoter methylation and expression in the cancer samples (R = -0.63, p = 5.99e-19). A lower MAGE-A3 methylation level was found to be associated with a worse patient survival (HR: 1.5, 95 % CI: 1.02-2.37, p = 0.04). In addition, we found that miRNA-mediated knockdown of MAGE-A3 expression in MKN1 cells caused a reduction in its proliferation and colony forming capacities, respectively. Under stress conditions MAGE-A3 was found to regulate the expression of Bax and p21. MAGE-A3 knock down also led to an increase in Puma and Noxa expression, thus contributing to an enhanced docetaxel sensitivity in the gastric cancer-derived cells. CONCLUSIONS: From our results we conclude that MAGE-A3 expression is regulated epigenetically by promoter methylation, and that its expression contributes to gastric cell proliferation and drug sensitivity. This study underscores the potential implications of MAGE-A3 as a therapeutic target and prognostic marker in gastric cancer patients.


Subject(s)
Antigens, Neoplasm/metabolism , Antineoplastic Agents/pharmacology , Drug Resistance, Neoplasm/drug effects , Neoplasm Proteins/metabolism , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Antigens, Neoplasm/genetics , Cell Cycle/drug effects , Cell Cycle/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , DNA Methylation/drug effects , DNA Methylation/genetics , Docetaxel , Gene Expression Regulation, Neoplastic/drug effects , Gene Silencing/drug effects , Humans , Neoplasm Proteins/genetics , Promoter Regions, Genetic , Stress, Physiological/drug effects , Survival Analysis , Taxoids/pharmacology , Tumor Stem Cell Assay
4.
Dis Model Mech ; 8(7): 743-53, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-26035378

ABSTRACT

Hepatocellular carcinoma (HCC) is a deadly disease, often unnoticed until the late stages, when treatment options become limited. Thus, there is a crucial need to identify biomarkers for early detection of developing HCC, as well as molecular pathways that would be amenable to therapeutic intervention. Although analysis of human HCC tissues and serum components may serve these purposes, inability of early detection also precludes possibilities of identification of biomarkers or pathways that are sequentially perturbed at earlier phases of disease progression. We have therefore explored the option of utilizing mouse models to understand in a systematic and longitudinal manner the molecular pathways that are progressively deregulated by various etiological factors in contributing to HCC formation, and we report the initial findings in characterizing their validity. Hepatitis B surface antigen transgenic mice, which had been exposed to aflatoxin B1 at various stages in life, were used as a hepatitis model. Our findings confirm a synergistic effect of both these etiological factors, with a gender bias towards males for HCC predisposition. Time-based aflatoxin B1 treatment also demonstrated the requirement of non-quiescent liver for effective transformation. Tumors from these models with various etiologies resemble human HCCs histologically and at the molecular level. Extensive molecular characterization revealed the presence of an 11-gene HCC-expression signature that was able to discern transformed human hepatocytes from primary cells, regardless of etiology, and from other cancer types. Moreover, distinct molecular pathways appear to be deregulated by various etiological agents en route to formation of HCCs, in which common pathways converge, highlighting the existence of etiology-specific as well as common HCC-specific molecular perturbations. This study therefore highlights the utility of these mouse models, which provide a rich resource for the longitudinal analysis of molecular changes and biomarkers associated with HCC that could be exploited further for therapeutic targeting.


Subject(s)
Liver Neoplasms, Experimental/etiology , Liver Neoplasms, Experimental/genetics , Aflatoxin B1/toxicity , Animals , Carcinogenesis/chemically induced , Carcinogenesis/genetics , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cell Proliferation , Disease Models, Animal , Female , Gene Expression Profiling , Hepatitis B/complications , Hepatitis B/pathology , Hepatitis B Surface Antigens/genetics , Humans , Liver/drug effects , Liver/metabolism , Liver/pathology , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Liver Neoplasms, Experimental/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic
5.
Carcinogenesis ; 36(4): 441-51, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25742747

ABSTRACT

Gastric cancer (GC) is the second leading cause of global cancer mortality worldwide. However, the molecular mechanism underlying its carcinogenesis and drug resistance is not well understood. To identify novel functionally important genes that were differentially expressed due to combinations of genetic and epigenetic changes, we analyzed datasets containing genome-wide mRNA expression, DNA copy number alterations and DNA methylation status from 154 primary GC samples and 47 matched non-neoplastic mucosa tissues from Asian patients. We used concepts of 'within' and 'between' statistical analysis to compare the difference between tumors and controls within each platform, and assessed the correlations between platforms. This 'multi-regulated gene (MRG)' analysis identified 126 differentially expressed genes that underwent a combination of copy number and DNA methylation changes. Most genes were located at genomic loci associated with GC. Statistical enrichment analysis showed that MRGs were enriched for cancer, GC and drug response. We analysed several MRGs that previously had not been associated with GC. Knockdown of DDX27, TH1L or IDH3G sensitized cells to epirubicin or cisplatin, and knockdown of RAI14 reduced cell proliferation. Further studies showed that overexpression of DDX27 reduced epirubicin-induced DNA damage and apoptosis. Levels of DDX27 mRNA and protein were increased in early-stage gastric tumors, and may be a potential diagnostic and prognostic marker for GC. In summary, we used an integrative bioinformatics strategy to identify novel genes that are altered in GC and regulate resistance of GC cells to drugs in vitro.


Subject(s)
Antineoplastic Agents/pharmacology , DEAD-box RNA Helicases/genetics , Drug Resistance, Neoplasm/genetics , Stomach Neoplasms/drug therapy , Stomach Neoplasms/genetics , Apoptosis/drug effects , Apoptosis/genetics , Calcium-Binding Proteins , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/genetics , Cisplatin/pharmacology , Cytoskeletal Proteins/genetics , DEAD-box RNA Helicases/biosynthesis , DNA Copy Number Variations/genetics , DNA Damage/drug effects , DNA Damage/genetics , DNA Methylation/genetics , Databases, Nucleic Acid , Epirubicin/pharmacology , Gastric Mucosa/cytology , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Histones/genetics , Humans , Nerve Tissue Proteins/genetics , Prognosis , RNA Interference , RNA, Small Interfering , Retrospective Studies , Transcription Factors/genetics
6.
Nat Cell Biol ; 17(4): 511-23, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25774835

ABSTRACT

The functional significance of the overexpression of unmutated TAp73, a homologue of the tumour suppressor p53, in multiple human cancers is unclear, but raises the possibility of unidentified roles in promoting tumorigenesis. We show here that TAp73 is stabilized by hypoxia, a condition highly prevalent in tumours, through HIF-1α-mediated repression of the ubiquitin ligase Siah1, which targets TAp73 for degradation. Consequently, TAp73-deficient tumours are less vascular and reduced in size, and conversely, TAp73 overexpression leads to increased vasculature. Moreover, we show that TAp73 is a critical regulator of the angiogenic transcriptome and is sufficient to directly activate the expression of several angiogenic genes.  Finally, expression of TAp73 positively correlates with these angiogenic genes in several human tumours, and the angiogenic gene signature is sufficient to segregate the TAp73(Hi)- from TAp73(Low)-expressing tumours. These data demonstrate a pro-angiogenic role for TAp73 in supporting tumorigenesis, providing a rationale for its overexpression in cancers.


Subject(s)
DNA-Binding Proteins/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Neoplasms/blood supply , Neovascularization, Pathologic/genetics , Nuclear Proteins/antagonists & inhibitors , Nuclear Proteins/metabolism , Tumor Suppressor Proteins/metabolism , Ubiquitin-Protein Ligases/antagonists & inhibitors , Animals , Cell Hypoxia , Cell Line, Tumor , Cell Transformation, Neoplastic/genetics , DNA-Binding Proteins/biosynthesis , DNA-Binding Proteins/genetics , Female , Gene Expression Regulation, Neoplastic , HCT116 Cells , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, SCID , Nuclear Proteins/biosynthesis , Nuclear Proteins/genetics , Protein Binding , Tumor Protein p73 , Tumor Suppressor Proteins/biosynthesis , Tumor Suppressor Proteins/genetics , Ubiquitin-Protein Ligases/genetics , Ubiquitination , Vascular Endothelial Growth Factor A/biosynthesis
7.
Gut ; 64(5): 707-19, 2015 May.
Article in English | MEDLINE | ID: mdl-25053715

ABSTRACT

OBJECTIVE: Gastric cancer (GC) is a deadly malignancy for which new therapeutic strategies are needed. Three transcription factors, KLF5, GATA4 and GATA6, have been previously reported to exhibit genomic amplification in GC. We sought to validate these findings, investigate how these factors function to promote GC, and identify potential treatment strategies for GCs harbouring these amplifications. DESIGN: KLF5, GATA4 and GATA6 copy number and gene expression was examined in multiple GC cohorts. Chromatin immunoprecipitation with DNA sequencing was used to identify KLF5/GATA4/GATA6 genomic binding sites in GC cell lines, and integrated with transcriptomics to highlight direct target genes. Phenotypical assays were conducted to assess the function of these factors in GC cell lines and xenografts in nude mice. RESULTS: KLF5, GATA4 and GATA6 amplifications were confirmed in independent GC cohorts. Although factor amplifications occurred in distinct sets of GCs, they exhibited significant mRNA coexpression in primary GCs, consistent with KLF5/GATA4/GATA6 cross-regulation. Chromatin immunoprecipitation with DNA sequencing revealed a large number of genomic sites co-occupied by KLF5 and GATA4/GATA6, primarily located at gene promoters and exhibiting higher binding strengths. KLF5 physically interacted with GATA factors, supporting KLF5/GATA4/GATA6 cooperative regulation on co-occupied genes. Depletion and overexpression of these factors, singly or in combination, reduced and promoted cancer proliferation, respectively, in vitro and in vivo. Among the KLF5/GATA4/GATA6 direct target genes relevant for cancer development, one target gene, HNF4α, was also required for GC proliferation and could be targeted by the antidiabetic drug metformin, revealing a therapeutic opportunity for KLF5/GATA4/GATA6 amplified GCs. CONCLUSIONS: KLF5/GATA4/GATA6 may promote GC development by engaging in mutual crosstalk, collaborating to maintain a pro-oncogenic transcriptional regulatory network in GC cells.


Subject(s)
GATA4 Transcription Factor/genetics , GATA6 Transcription Factor/genetics , Gene Expression Regulation, Neoplastic/genetics , Kruppel-Like Transcription Factors/genetics , Stomach Neoplasms/genetics , Animals , Cell Proliferation , Cell Transformation, Neoplastic/genetics , Cell Transformation, Neoplastic/metabolism , GATA4 Transcription Factor/biosynthesis , GATA6 Transcription Factor/biosynthesis , Gene Expression Profiling/methods , Gene Silencing , Genetic Predisposition to Disease , Heterografts , Humans , Kruppel-Like Transcription Factors/biosynthesis , Mice, Nude , Neoplasm Transplantation , Oncogenes/genetics , Promoter Regions, Genetic , Stomach Neoplasms/metabolism , Stomach Neoplasms/pathology , Tumor Cells, Cultured
8.
J Alzheimers Dis ; 44(1): 57-61, 2015.
Article in English | MEDLINE | ID: mdl-25201778

ABSTRACT

We previously reported TOMM40 to be significantly down-regulated in whole blood of Alzheimer's disease (AD) subjects at baseline and after one-year. In this longitudinal follow-up study of TOMM40 expression up to 2 years, we performed 6-monthly assessments for the first year and 2nd year blood sampling on 27 probable AD subjects compared with age- and gender-matched controls. TOMM40 gene expression remained significantly lower in AD patients at all time-points compared to controls, supported by confirmatory RT-PCR results. Our findings of consistently lower TOMM40 expression on longitudinal 2-year sampling support its potential role as a diagnostic blood AD biomarker.


Subject(s)
Alzheimer Disease/metabolism , Down-Regulation , Membrane Transport Proteins/metabolism , Aged , Aged, 80 and over , Apolipoproteins E/genetics , Case-Control Studies , Down-Regulation/physiology , Female , Gene Expression Profiling , Humans , Longitudinal Studies , Male , Membrane Transport Proteins/genetics , Mitochondrial Precursor Protein Import Complex Proteins , Oligonucleotide Array Sequence Analysis , Psychiatric Status Rating Scales , RNA, Messenger/metabolism , ROC Curve , Time Factors
9.
Nat Commun ; 5: 4361, 2014 Jul 10.
Article in English | MEDLINE | ID: mdl-25008978

ABSTRACT

Chromatin alterations are fundamental hallmarks of cancer. To study chromatin alterations in primary gastric adenocarcinomas, we perform nanoscale chromatin immunoprecipitation sequencing of multiple histone modifications in five gastric cancers and matched normal tissues. We identify hundreds of somatically altered promoters and predicted enhancers. Many cancer-associated promoters localize to genomic sites lacking previously annotated transcription start sites (cryptic promoters), driving expression of nearby genes involved in gastrointestinal cancer, embryonic development and tissue specification. Cancer-associated promoters overlap with embryonic stem cell regions targeted by polycomb repressive complex 2, exhibiting promoter bivalency and DNA methylation loss. We identify somatically acquired elements exhibiting germline allelic biases and non-coding somatic mutations creating new promoters. Our findings demonstrate the feasibility of profiling chromatin from solid tumours with limited tissue to identify regulatory elements, transcriptional patterns and regulatory genetic variants associated with cancer.


Subject(s)
Adenocarcinoma/genetics , Chromatin/genetics , DNA Fingerprinting/methods , Nanotechnology/methods , Promoter Regions, Genetic/genetics , Regulatory Elements, Transcriptional/genetics , Stomach Neoplasms/genetics , Adenocarcinoma/pathology , Alleles , Case-Control Studies , DNA/genetics , DNA Methylation , DNA, Neoplasm/genetics , Histones/genetics , Humans , Mutation/genetics , Stomach Neoplasms/pathology , Transcription Initiation Site
10.
PLoS One ; 9(3): e91666, 2014.
Article in English | MEDLINE | ID: mdl-24626295

ABSTRACT

We aimed to identify a prostate cancer DNA hypermethylation microarray signature (denoted as PHYMA) that differentiates prostate cancer from benign prostate hyperplasia (BPH), high from low-grade and lethal from non-lethal cancers. This is a non-randomized retrospective study in 111 local Asian men (87 prostate cancers and 24 BPH) treated from 1995 to 2009 in our institution. Archival prostate epithelia were laser-capture microdissected and genomic DNA extracted and bisulfite-converted. Samples were profiled using Illumina GoldenGate Methylation microarray, with raw data processed by GenomeStudio. A classification model was generated using support vector machine, consisting of a 55-probe DNA methylation signature of 46 genes. The model was independently validated on an internal testing dataset which yielded cancer detection sensitivity and specificity of 95.3% and 100% respectively, with overall accuracy of 96.4%. Second validation on another independent western cohort yielded 89.8% sensitivity and 66.7% specificity, with overall accuracy of 88.7%. A PHYMA score was developed for each sample based on the state of methylation in the PHYMA signature. Increasing PHYMA score was significantly associated with higher Gleason score and Gleason primary grade. Men with higher PHYMA scores have poorer survival on univariate (p = 0.0038, HR = 3.89) and multivariate analyses when controlled for (i) clinical stage (p = 0.055, HR = 2.57), and (ii) clinical stage and Gleason score (p = 0.043, HR = 2.61). We further performed bisulfite genomic sequencing on 2 relatively unknown genes to demonstrate robustness of the assay results. PHYMA is thus a signature with high sensitivity and specificity for discriminating tumors from BPH, and has a potential role in early detection and in predicting survival.


Subject(s)
DNA Methylation , Gene Expression Regulation, Neoplastic , Prostatic Neoplasms/genetics , Aged , Aged, 80 and over , Asian People , Cell Differentiation , Epigenesis, Genetic , Gene Expression Profiling , Humans , Male , Middle Aged , Multivariate Analysis , Oligonucleotide Array Sequence Analysis , Prognosis , Proportional Hazards Models , Prostatic Hyperplasia/diagnosis , Prostatic Hyperplasia/pathology , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/ethnology , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity
11.
BMC Res Notes ; 6: 562, 2013 Dec 28.
Article in English | MEDLINE | ID: mdl-24373486

ABSTRACT

BACKGROUND: Dual in-situ hybridization (DISH) assay is a relatively new assay for evaluating Human Epidermal Growth Factor Receptor 2 (HER2) genomic amplification. Optimization protocol for the assay is not yet well established, especially for archival tissues. Although there is a recommended nominal protocol, it is not suited for formalin-fixed and paraffin-embedded (FFPE) samples that were archived for long periods. FINDINGS: In a study on local population of mucinous epithelial ovarian cancer, we developed a series of optimization protocols based on the age of samples to improve success of the DISH assay. A decision workflow was generated to facilitate individualization of further optimization protocols. The optimizations were evaluated on 92 whole tissue sections of FFPE mucinous ovarian tumors dating from 1990 to 2011. Overall, 79 samples were successfully assayed for DISH using the series of optimization protocols. We found samples older than 1 year required further optimization beyond the nominal protocol recommended. Thirteen samples were not further assayed after first DISH assay due to inadequately preserved nuclear morphology with no ISH signals throughout the tissue section. CONCLUSION: The study revealed age of samples and storage conditions were major factors in successful DISH assays. Samples that were ten years or less in age, and archived in-house were successfully optimized, whereas older samples, which were also archived off-site, have a higher frequency of unsuccessful optimizations. The study provides practical and important guidelines for the new DISH assay which can facilitate successful HER2 evaluation in ovarian cancers and possibly other cancers as well.


Subject(s)
In Situ Hybridization/methods , Neoplasms, Glandular and Epithelial/diagnosis , Ovarian Neoplasms/diagnosis , Receptor, ErbB-2/genetics , Carcinoma, Ovarian Epithelial , Female , Humans , Neoplasms, Glandular and Epithelial/genetics , Ovarian Neoplasms/genetics , Paraffin Embedding , Time Factors , Tissue Fixation
12.
Gastroenterology ; 145(3): 554-65, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23684942

ABSTRACT

BACKGROUND & AIMS: Almost all gastric cancers are adenocarcinomas, which have considerable heterogeneity among patients. We sought to identify subtypes of gastric adenocarcinomas with particular biological properties and responses to chemotherapy and targeted agents. METHODS: We compared gene expression patterns among 248 gastric tumors; using a robust method of unsupervised clustering, consensus hierarchical clustering with iterative feature selection, we identified 3 major subtypes. We developed a classifier for these subtypes and validated it in 70 tumors from a different population. We identified distinct genomic and epigenomic properties of the subtypes. We determined drug sensitivities of the subtypes in primary tumors using clinical survival data, and in cell lines through high-throughput drug screening. RESULTS: We identified 3 subtypes of gastric adenocarcinoma: proliferative, metabolic, and mesenchymal. Tumors of the proliferative subtype had high levels of genomic instability, TP53 mutations, and DNA hypomethylation. Cancer cells of the metabolic subtype were more sensitive to 5-fluorouracil than the other subtypes. Furthermore, in 2 independent groups of patients, those with tumors of the metabolic subtype appeared to have greater benefits with 5-fluorouracil treatment. Tumors of the mesenchymal subtype contain cells with features of cancer stem cells, and cell lines of this subtype are particularly sensitive to phosphatidylinositol 3-kinase-AKT-mTOR inhibitors in vitro. CONCLUSIONS: Based on gene expression patterns, we classified gastric cancers into 3 subtypes, and validated these in an independent set of tumors. The subgroups have differences in molecular and genetic features and response to therapy; this information might be used to select specific treatment approaches for patients with gastric cancer.


Subject(s)
Adenocarcinoma/classification , Antineoplastic Agents/therapeutic use , Biomarkers, Tumor/genetics , Fluorouracil/therapeutic use , Gene Expression Regulation, Neoplastic , Phosphoinositide-3 Kinase Inhibitors , Stomach Neoplasms/classification , Adenocarcinoma/drug therapy , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Aged , Bayes Theorem , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Cluster Analysis , Genetic Association Studies , Humans , Middle Aged , Models, Statistical , Proto-Oncogene Proteins c-akt/antagonists & inhibitors , Regression Analysis , Retrospective Studies , Stomach Neoplasms/drug therapy , Stomach Neoplasms/genetics , Stomach Neoplasms/metabolism , Survival Analysis , TOR Serine-Threonine Kinases/antagonists & inhibitors , Treatment Outcome
13.
Dis Model Mech ; 6(5): 1146-58, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23649821

ABSTRACT

Myopia is a huge public health problem worldwide, reaching the highest incidence in Asia. Identification of susceptible genes is crucial for understanding the biological basis of myopia. In this paper, we have identified and characterized a functional myopia-associated gene using a specific mouse-knockout model. Mice lacking the muscarinic cholinergic receptor gene (M2; also known as Chrm2) were less susceptible to lens-induced myopia compared with wild-type mice, which showed significantly increased axial length and vitreous chamber depth when undergoing experimental induction of myopia. The key findings of this present study are that the sclera of M2 mutant mice has higher expression of collagen type I and lower expression of collagen type V than do wild-type mice and mice that are mutant for other muscarinic subtypes, and, therefore, M2 mutant mice were resistant to the development of experimental myopia. Pharmacological blockade of M2 muscarinic receptor proteins retarded myopia progression in the mouse. These results suggest for the first time a role of M2 in growth-related changes in extracellular matrix genes during myopia development in a mammalian model. M2 receptor antagonists might thus provide a targeted therapeutic approach to the management of this refractive error.


Subject(s)
Disease Progression , Myopia/metabolism , Myopia/pathology , Receptor, Muscarinic M2/metabolism , Adult , Aged , Alkaloids/pharmacology , Alkaloids/therapeutic use , Animals , Cell Proliferation/drug effects , Collagen/genetics , Collagen/metabolism , Extracellular Matrix/drug effects , Extracellular Matrix/metabolism , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/pathology , Furans/pharmacology , Furans/therapeutic use , Gene Knockdown Techniques , Humans , Mice , Mice, Knockout , Middle Aged , Myopia/drug therapy , Naphthalenes/pharmacology , Naphthalenes/therapeutic use , Piperidines/pharmacology , Piperidines/therapeutic use , Pirenzepine/analogs & derivatives , Pirenzepine/pharmacology , Pirenzepine/therapeutic use , RNA, Small Interfering/metabolism , Receptor, Muscarinic M2/antagonists & inhibitors , Receptor, Muscarinic M2/genetics , Sclera/drug effects , Sclera/metabolism , Sclera/pathology , Up-Regulation/drug effects
14.
PLoS One ; 8(4): e61565, 2013.
Article in English | MEDLINE | ID: mdl-23620766

ABSTRACT

Mucinous epithelial ovarian cancer has a poor prognosis in the advanced stages and responds poorly to conventional chemotherapy. We aim to elucidate the clinicopathological factors and incidence of HER2 expression of this cancer in a large Asian retrospective cohort from Singapore. Of a total of 133 cases, the median age at diagnosis was 48.3 years (range, 15.8-89.0 years), comparatively younger than western cohorts. Most were Chinese (71%), followed by Malays (16%), others (9.0%), and Indians (5%). 24% were noted to have a significant family history of malignancy of which breast and gastrointestinal cancers the most prominent. Majority of the patients (80%) had stage I disease at diagnosis. Information on HER2 status was available in 113 cases (85%). Of these, 31 cases (27.4%) were HER2+, higher than 18.8% reported in western population. HER2 positivity appeared to be lower among Chinese and higher among Malays patients (p = 0.052). With the current standard of care, there was no discernible impact of HER2 status on overall survival. (HR = 1.79; 95% CI, 0.66-4.85; p = 0.249). On the other hand, positive family history of cancer, presence of lymphovascular invasion, and ovarian surface involvements were significantly associated with inferior overall survival on univariate and continued to be statistically significant after adjustment for stage. While these clinical factors identify high risk patients, it is promising that the finding of a high incidence of HER2 in our Asian population may allow development of a HER2 targeted therapy to improve the management of mucinous ovarian cancers.


Subject(s)
Adenocarcinoma, Mucinous/genetics , Adenocarcinoma, Mucinous/pathology , Asian People/genetics , Gene Amplification , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Receptor, ErbB-2/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Disease-Free Survival , Family , Female , Humans , Middle Aged , Singapore , Young Adult
15.
J Alzheimers Dis ; 34(2): 399-405, 2013.
Article in English | MEDLINE | ID: mdl-23234877

ABSTRACT

We previously reported TOMM40 was significantly down-regulated in whole blood of Alzheimer's disease (AD) subjects. In this study, we examined whole blood gene profiling differences over a one-year period comparing early AD subjects based on disease progression. 6-monthly assessments and blood sampling on 29 probable AD subjects compared with age- and gender-matched controls were performed. AD subjects with change in Clinical Dementia Rating-Sum of Boxes (CDR-SB) score of ≥2 points/year were classified as fast-progressors and those with CDR-SB change of <2 points/year were classified as slow-progressors. We found statistically significant upregulation in KIR2DL5A, SLC2A8, and PLOD1 for fast- (n = 8) compared with slow-progressors (n = 21) across the time-points. TOMM40 gene expression remained significantly lower in AD patients at all time-points compared to controls, supporting our previous findings. Our novel findings of specific gene expression differences between fast- and slow-progressors in combination with consistently lower TOMM40 expression, suggest their potential role as prognostic blood biomarkers to predict progression in early AD.


Subject(s)
Alzheimer Disease/blood , Down-Regulation/physiology , Glucose Transport Proteins, Facilitative/biosynthesis , Leukocytes, Mononuclear/metabolism , Membrane Transport Proteins/metabolism , Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase/biosynthesis , Receptors, KIR2DL5/biosynthesis , Up-Regulation/physiology , Aged , Aged, 80 and over , Alzheimer Disease/diagnosis , Alzheimer Disease/genetics , Biomarkers/blood , Disease Progression , Early Diagnosis , Female , Gene Expression Profiling/methods , Glucose Transport Proteins, Facilitative/genetics , Humans , Longitudinal Studies , Male , Membrane Transport Proteins/genetics , Mitochondrial Precursor Protein Import Complex Proteins , Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase/genetics , Prospective Studies , Receptors, KIR2DL5/genetics
16.
Nat Genet ; 45(1): 76-82, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23202124

ABSTRACT

Birth weight within the normal range is associated with a variety of adult-onset diseases, but the mechanisms behind these associations are poorly understood. Previous genome-wide association studies of birth weight identified a variant in the ADCY5 gene associated both with birth weight and type 2 diabetes and a second variant, near CCNL1, with no obvious link to adult traits. In an expanded genome-wide association meta-analysis and follow-up study of birth weight (of up to 69,308 individuals of European descent from 43 studies), we have now extended the number of loci associated at genome-wide significance to 7, accounting for a similar proportion of variance as maternal smoking. Five of the loci are known to be associated with other phenotypes: ADCY5 and CDKAL1 with type 2 diabetes, ADRB1 with adult blood pressure and HMGA2 and LCORL with adult height. Our findings highlight genetic links between fetal growth and postnatal growth and metabolism.


Subject(s)
Birth Weight/genetics , Body Height/genetics , Fetal Development/genetics , Genetic Linkage , Quantitative Trait Loci , Adult , Blood Pressure/genetics , Diabetes Mellitus, Type 2/genetics , Female , Genetic Predisposition to Disease , Genome-Wide Association Study , Humans , Infant, Newborn , Male , Meta-Analysis as Topic , Polymorphism, Single Nucleotide
17.
Sci Transl Med ; 4(156): 156ra140, 2012 Oct 17.
Article in English | MEDLINE | ID: mdl-23076357

ABSTRACT

Epigenetic alterations are fundamental hallmarks of cancer genomes. We surveyed the landscape of DNA methylation alterations in gastric cancer by analyzing genome-wide CG dinucleotide (CpG) methylation profiles of 240 gastric cancers (203 tumors and 37 cell lines) and 94 matched normal gastric tissues. Cancer-specific epigenetic alterations were observed in 44% of CpGs, comprising both tumor hyper- and hypomethylation. Twenty-five percent of the methylation alterations were significantly associated with changes in tumor gene expression. Whereas most methylation-expression correlations were negative, several positively correlated methylation-expression interactions were also observed, associated with CpG sites exhibiting atypical transcription start site distances and gene body localization. Methylation clustering of the tumors revealed a CpG island methylator phenotype (CIMP) subgroup associated with widespread hypermethylation, young patient age, and adverse patient outcome in a disease stage-independent manner. CIMP cell lines displayed sensitivity to 5-aza-2'-deoxycytidine, a clinically approved demethylating drug. We also identified long-range regions of epigenetic silencing (LRESs) in CIMP tumors. Combined analysis of the methylation, gene expression, and drug treatment data suggests that certain LRESs may silence specific genes within the region, rather than all genes. Finally, we discovered regions of long-range tumor hypomethylation, associated with increased chromosomal instability. Our results provide insights into the epigenetic impact of environmental and biological agents on gastric epithelial cells, which may contribute to cancer.


Subject(s)
DNA Methylation , Epigenesis, Genetic , Stomach Neoplasms/genetics , Animals , Azacitidine/analogs & derivatives , Azacitidine/pharmacology , Cell Proliferation , Chromosomal Instability , Cluster Analysis , CpG Islands , Decitabine , Epigenomics , Gastric Mucosa/metabolism , Gene Expression Regulation, Neoplastic , Gene Silencing , Humans , Mice , Neoplasm Transplantation , Phenotype
18.
BMC Med Genomics ; 5: 34, 2012 Aug 09.
Article in English | MEDLINE | ID: mdl-22876838

ABSTRACT

BACKGROUND: While there is strong evidence for phosphatidylinositol 3-kinase (PI3K) involvement in cancer development, there is limited information about the role of PI3K regulatory subunits. PIK3R3, the gene that encodes the PI3K regulatory subunit p55γ, is over-expressed in glioblastoma and ovarian cancers, but its expression in gastric cancer (GC) is not known. We thus used genetic and bioinformatic approaches to examine PIK3R3 expression and function in GC, the second leading cause of cancer mortality world-wide and highly prevalent among Asians. METHODS: Primary GC and matched non-neoplastic mucosa tissue specimens from a unique Asian patient gastric cancer library were comprehensively profiled with platforms that measured genome-wide mRNA expression, DNA copy number variation, and DNA methylation status. Function of PIK3R3 was predicted by IPA pathway analysis of co-regulated genes with PIK3R3, and further investigated by siRNA knockdown studies. Cell proliferation was estimated by crystal violet dye elution and BrdU incorporation assay. Cell cycle distribution was analysed by FACS. RESULTS: PIK3R3 was significantly up-regulated in GC specimens (n = 126, p < 0.05), and 9.5 to 15% tumors showed more than 2 fold increase compare to the paired mucosa tissues. IPA pathway analysis showed that PIK3R3 promoted cellular growth and proliferation. Knockdown of PIK3R3 decreased the growth of GC cells, induced G0/G1 cell cycle arrest, decreased retinoblastoma protein (Rb) phosphorylation, cyclin D1, and PCNA expression. CONCLUSION: Using a combination of genetic, bioinformatic, and molecular biological approaches, we showed that PIK3R3 was up-regulated in GC and promoted cell cycle progression and proliferation; and thus may be a potential new therapeutic target for GC.


Subject(s)
Asian People/genetics , Computational Biology/methods , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Phosphatidylinositol 3-Kinases/genetics , Stomach Neoplasms/enzymology , Stomach Neoplasms/genetics , Cell Proliferation , Cyclin D1/genetics , Cyclin D1/metabolism , G1 Phase Cell Cycle Checkpoints/genetics , Gastric Mucosa/metabolism , Gastric Mucosa/pathology , Gene Knockdown Techniques , Humans , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Phosphorylation , Protein Subunits/genetics , Proto-Oncogene Proteins c-akt/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism , Resting Phase, Cell Cycle/genetics , Retinoblastoma Protein/metabolism , Signal Transduction/genetics , Stomach Neoplasms/pathology
19.
Oncologist ; 17(10): 1286-93, 2012.
Article in English | MEDLINE | ID: mdl-22829569

ABSTRACT

BACKGROUND: In 2008, the Federation of Gynecology and Obstetrics (FIGO) revised their 1988 staging system for uterine leiomyosarcomas. In this article, we compare performance of the 2008 and 1988 FIGO systems. METHODS: Individual case data were manually culled. Staging was retrospectively assessed according to revised and 1998 FIGO criteria. Overall survival distribution was assessed by the Kaplan-Meier method. Harrell's concordance index was used to assess the discriminative ability of a fitted Cox model to predict overall survival. RESULTS: A total of 110 cases of uterine leiomyosarcomas were reviewed and data from 88 patients were analyzed. In all, 71% of cases were classified as stage I, 7% as stage II, 3% as stage III, and 19% as stage IV under the revised FIGO staging system. Nine patients (10.2%) were downstaged and none were upstaged. The revised FIGO system did not show a significant improvement over the 1988 FIGO system in the ability to discriminate the risk of death of patients between stages, with concordance indexes of 0.70 and 0.71, respectively. Most patients were classified as stage I with age, tumor grade, tumor size, and lymphovascular invasion as prognostic factors. CONCLUSION: The 2008 revised FIGO staging system for uterine leiomyosarcomas does not perform better than the 1988 system for uterine endometrial carcinomas. A better staging system is needed for these cases.


Subject(s)
Leiomyosarcoma/pathology , Uterine Neoplasms/pathology , Adult , Aged , Asian People , Female , Humans , Middle Aged , Neoplasm Staging , Prognosis , Survival Analysis
20.
Mol Vis ; 18: 1436-48, 2012.
Article in English | MEDLINE | ID: mdl-22736935

ABSTRACT

PURPOSE: The aim of this study was to identify the genes and pathways underlying the growth of the mouse sclera during postnatal development. METHODS: Total RNA was isolated from each of 30 single mouse sclera (n=30, 6 sclera each from 1-, 2-, 3-, 6-, and 8-week-old mice) and reverse-transcribed into cDNA using a T7-N(6) primer. The resulting cDNA was fragmented, labeled with biotin, and hybridized to a Mouse Gene 1.0 ST Array. ANOVA analysis was then performed using Partek Genomic Suite 6.5 beta and differentially expressed transcript clusters were filtered based on a selection criterion of ≥ 2 relative fold change at a false discovery rate of ≤ 5%. Genes identified as involved in the main biologic processes during postnatal scleral development were further confirmed using qPCR. A possible pathway that contributes to the postnatal development of the sclera was investigated using Ingenuity Pathway Analysis software. RESULTS: The hierarchical clustering of all time points showed that they did not cluster according to age. The highest number of differentially expressed transcript clusters was found when week 1 and week 2 old scleral tissues were compared. The peroxisome proliferator- activated receptor gamma coactivator 1-alpha (Ppargc1a) gene was found to be involved in the networks generated using Ingenuity Pathway Studio (IPA) from the differentially expressed transcript cluster lists of week 2 versus 1, week 3 versus 2, week 6 versus 3, and week 8 versus 6. The gene expression of Ppargc1a varied during scleral growth from week 1 to 2, week 2 to 3, week 3 to 6, and week 6 to 8 and was found to interact with a different set of genes at different scleral growth stages. Therefore, this indicated that Ppargc1a might play a role in scleral growth during postnatal weeks 1 to 8. CONCLUSIONS: Gene expression of eye diseases should be studied as early as postnatal weeks 1-2 to ensure that any changes in gene expression pattern during disease development are detected. In addition, we propose that Ppargc1a might play a role in regulating postnatal scleral development by interacting with a different set of genes at different scleral growth stages.


Subject(s)
Eye Proteins/genetics , Gene Expression Regulation, Developmental , Gene Regulatory Networks , Genome , Sclera/metabolism , Trans-Activators/genetics , Animals , Animals, Newborn , Eye Proteins/metabolism , Gene Expression Profiling , Mice , Mice, Inbred BALB C , Multigene Family , Oligonucleotide Array Sequence Analysis , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , RNA, Messenger , Reverse Transcriptase Polymerase Chain Reaction , Sclera/growth & development , Software , Time Factors , Trans-Activators/metabolism , Transcription Factors
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