ABSTRACT
MicroRNAs (miRNAs) are critical post-transcriptional regulators. Based on a previous genome-wide association (GWA) scan, we conducted a polymorphism in microRNA target sites (poly-miRTS)-centric multistage meta-analysis for lumbar spine (LS)-, total hip (HIP)- and femoral neck (FN)-bone mineral density (BMD). In stage I, 41 102 poly-miRTSs were meta-analyzed in seven cohorts with a genome-wide significance (GWS) α = 0.05/41 102 = 1.22 × 10(-6). By applying α = 5 × 10(-5) (suggestive significance), 11 poly-miRTSs were selected, with FGFRL1 rs4647940 and PRR5 rs3213550 as top signals for FN-BMD (P = 7.67 × 10(-6) and 1.58 × 10(-5)) in gender-combined sample. In stage II in silico replication (two cohorts), FGFRL1 rs4647940 was the only signal marginally replicated for FN-BMD (P = 5.08 × 10(-3)) at α = 0.10/11 = 9.09 × 10(-3). PRR5 rs3213550 was also selected based on biological significance. In stage III de novo genotyping replication (two cohorts), FGFRL1 rs4647940 was the only signal significantly replicated for FN-BMD (P = 7.55 × 10(-6)) at α = 0.05/2 = 0.025 in gender-combined sample. Aggregating three stages, FGFRL1 rs4647940 was the single stage I-discovered and stages II- and III-replicated signal attaining GWS for FN-BMD (P = 8.87 × 10(-12)). Dual-luciferase reporter assays demonstrated that FGFRL1 3' untranslated region harboring rs4647940 appears to be hsa-miR-140-5p's target site. In a zebrafish microinjection experiment, dre-miR-140-5p is shown to exert a dramatic impact on craniofacial skeleton formation. Taken together, we provided functional evidence for a novel FGFRL1 poly-miRTS rs4647940 in a previously known 4p16.3 locus, and experimental and clinical genetics studies have shown both FGFRL1 and hsa-miR-140-5p are important for bone formation.
Subject(s)
3' Untranslated Regions , Bone Density/genetics , Genetic Loci , MicroRNAs/genetics , Polymorphism, Genetic , Receptor, Fibroblast Growth Factor, Type 5/genetics , Female , Genome-Wide Association Study , Humans , MaleABSTRACT
KEY POINTS: Synaptic excitation and inhibition must be properly balanced in individual neurons and neuronal networks to allow proper brain function. Disrupting this balance may lead to autism spectral disorders and epilepsy. We show the basic helix-loop-helix transcription factor NeuroD2 promotes inhibitory synaptic drive but also decreases cell-intrinsic neuronal excitability of cortical pyramidal neurons both in vitro and in vivo. We identify two genes potentially downstream of NeuroD2-mediated transcription that regulate these parameters: gastrin-releasing peptide and the small conductance, calcium-activated potassium channel, SK2. Our results reveal an important function for NeuroD2 in balancing synaptic neurotransmission and intrinsic excitability. Our results offer insight into how synaptic innervation and intrinsic excitability are coordinated during cortical development. ABSTRACT: Synaptic excitation and inhibition must be properly balanced in individual neurons and neuronal networks for proper brain function. Disruption of this balance during development may lead to autism spectral disorders and epilepsy. Synaptic excitation is counterbalanced by synaptic inhibition but also by attenuation of cell-intrinsic neuronal excitability. To maintain proper excitation levels during development, neurons must sense activity over time and regulate the expression of genes that control these parameters. While this is a critical process, little is known about the transcription factors involved in coordinating gene expression to control excitatory/inhibitory synaptic balance. We show here that the basic helix-loop-helix transcription factor NeuroD2 promotes inhibitory synaptic drive but also decreases cell-intrinsic neuronal excitability of cortical pyramidal neurons both in vitro and in vivo as shown by ex vivo analysis of a NeuroD2 knockout mouse. Using microarray analysis and comparing wild-type and NeuroD2 knockout cortical networks, we identified two potential gene targets of NeuroD2 that contribute to these processes: gastrin-releasing peptide (GRP) and the small conductance, calcium-activated potassium channel, SK2. We found that the GRP receptor antagonist RC-3059 and the SK2 specific blocker apamin partially reversed the effects of increased NeuroD2 expression on inhibitory synaptic drive and action potential repolarization, respectively. Our results reveal an important function for NeuroD2 in balancing synaptic neurotransmission and intrinsic excitability and offer insight into how these processes are coordinated during cortical development.
Subject(s)
Basic Helix-Loop-Helix Transcription Factors/physiology , Neuropeptides/physiology , Pyramidal Cells/physiology , Somatosensory Cortex/physiology , Synapses/physiology , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Cells, Cultured , Gastrin-Releasing Peptide/genetics , Inhibitory Postsynaptic Potentials , Mice, Knockout , Neuropeptides/genetics , Rats , Small-Conductance Calcium-Activated Potassium Channels/geneticsABSTRACT
MicroRNAs (miRs) function as tumor suppressors or oncogenes in multiple tumor types. Although miR expression is tightly regulated, the molecular basis of miR regulation is poorly understood. Here, we investigated the influence of the histone demethylase Jumonji/ARID1 B (JARID1B) on miR regulation in breast tumor cells. In MCF-7 cells with stable RNAi-mediated suppression of JARID1B expression we identified altered regulation of multiple miRs including let-7e, a member of the let-7 family of tumor suppressor miRs. Chromatin immunoprecipitation analysis demonstrated JARID1B binding to the let-7e promoter region as well as removal of the of H3K4me3 histone mark associated with active gene expression. These results suggest that JARID1B epigenetically represses let-7e expression. JARID1B stimulates tumor cell proliferation by promoting the G(1) to S transition. As predicted, suppression of JARID1B resulted in an accumulation of MCF-7 cells in G(1). We confirmed that cyclin D1, which also promotes G(1) progression, is a direct target of let-7e, and we show that cyclin D1 expression is suppressed in JARID1B knockdown cells. Cyclin D1 expression and cell cycle progression were restored following inhibition of let-7e, suggesting that JARID1B repression of let-7e contributes to cyclin D1 expression and JARID1B-mediated cell cycle progression. Our results indicate that the JARID1B demethylase contributes to tumor cell proliferation through the epigenetic repression of a tumor suppressor miR.
Subject(s)
Breast Neoplasms/pathology , Cell Cycle/genetics , Epigenesis, Genetic/genetics , Gene Silencing , Jumonji Domain-Containing Histone Demethylases/metabolism , MicroRNAs/genetics , Nuclear Proteins/metabolism , Repressor Proteins/metabolism , Cell Line, Tumor , Cyclin D1/genetics , Female , Histones/chemistry , Histones/metabolism , Humans , Lysine , MethylationABSTRACT
Tamoxifen is the most commonly prescribed therapy for patients with estrogen receptor (ER)α-positive breast tumors. Tumor resistance to tamoxifen remains a serious clinical problem especially in patients with tumors that also overexpress human epidermal growth factor receptor 2 (HER2). Current preclinical models of HER2 overexpression fail to recapitulate the clinical spectrum of endocrine resistance associated with HER2/ER-positive tumors. Here, we show that ectopic expression of a clinically important oncogenic isoform of HER2, HER2Δ16, which is expressed in >30% of ER-positive breast tumors, promotes tamoxifen resistance and estrogen independence of MCF-7 xenografts. MCF-7/HER2Δ16 cells evade tamoxifen through upregulation of BCL-2, whereas mediated suppression of BCL-2 expression or treatment of MCF-7/HER2Δ16 cells with the BCL-2 family pharmacological inhibitor ABT-737 restores tamoxifen sensitivity. Tamoxifen-resistant MCF-7/HER2Δ16 cells upregulate BCL-2 protein levels in response to suppressed ERα signaling mediated by estrogen withdrawal, tamoxifen treatment or fulvestrant treatment. In addition, HER2Δ16 expression results in suppression of BCL-2-targeting microRNAs miR-15a and miR-16. Reintroduction of miR-15a/16 reduced tamoxifen-induced BCL-2 expression and sensitized MCF-7/HER2Δ16 to tamoxifen. Conversely, inhibition of miR-15a/16 in tamoxifen-sensitive cells activated BCL-2 expression and promoted tamoxifen resistance. Our results suggest that HER2Δ16 expression promotes endocrine-resistant HER2/ERα-positive breast tumors and in contrast to wild-type HER2, preclinical models of HER2Δ16 overexpression recapitulate multiple phenotypes of endocrine-resistant human breast tumors. The mechanism of HER2Δ16 therapeutic evasion, involving tamoxifen-induced upregulation of BCL-2 and suppression of miR-15a/16, provides a template for unique therapeutic interventions combining tamoxifen with modulation of microRNAs and/or ABT-737-mediated BCL-2 inhibition and apoptosis.
Subject(s)
Breast Neoplasms/drug therapy , Estrogen Antagonists/therapeutic use , Genes, bcl-2 , MicroRNAs/antagonists & inhibitors , Receptor, ErbB-2/physiology , Tamoxifen/therapeutic use , Animals , Breast Neoplasms/pathology , Cell Line, Tumor , Drug Resistance, Neoplasm , Female , Gene Expression Regulation, Neoplastic , Humans , Mice , Mice, Nude , MicroRNAs/physiologyABSTRACT
BACKGROUND: Tumor resistance to the selective estrogen receptor modulator tamoxifen remains a serious clinical problem especially in patients with tumors that also overexpress HER2. We have recently demonstrated that the clinically important isoform of HER2, HERΔ16, promotes therapeutically refractory breast cancer including resistance to endocrine therapy. Likewise additional breast tumor cell models of tamoxifen resistance have been developed that do not involve HER2 overexpression. However, a unifying molecular mechanism of tamoxifen resistance has remained elusive. RESULTS: Here we analyzed multiple cell models of tamoxifen resistance derived from MCF-7 cells to examine the influence of microRNAs (miRNAs) on tamoxifen resistance. We compared miRNA expression profiles of tamoxifen sensitive MCF-7 cells and tamoxifen resistant MCF-7/HER2Δ16 cells. We observed significant and dramatic downregulation of miR-342 in the MCF-7/HER2Δ16 cell line as well as the HER2 negative but tamoxifen resistant MCF-7 variants TAMR1 and LCC2. Restoring miR-342 expression in the MCF-7/HER2Δ16 and TAMR1 cell lines sensitized these cells to tamoxifen-induced apoptosis with a dramatic reduction in cell growth. Expression of miR-342 was also reduced in a panel of tamoxifen refractory human breast tumors, underscoring the potential clinical importance of miR-342 downregulation. Towards the goal of identifying direct and indirect targets of miR-342 we restored miR-342 expression in MCF-7/HER2Δ16 cells and analyzed changes in global gene expression by microarray. The impact of miR-342 on gene expression in MCF-7/HER2Δ16 cells was not limited to miR-342 in silica predicted targets. Ingenuity Pathways Analysis of the dataset revealed a significant influence of miR-342 on multiple tumor cell cycle regulators. CONCLUSIONS: Our findings suggest that miR-342 regulates tamoxifen response in breast tumor cell lines and our clinical data indicates a trend towards reduced miR-342 expression and tamoxifen resistance. In addition, our results suggest that miR-342 regulates expression of genes involved in tamoxifen mediated tumor cell apoptosis and cell cycle progression. Restoring miR-342 expression may represent a novel therapeutic approach to sensitizing and suppressing the growth of tamoxifen refractory breast tumors.
Subject(s)
Antineoplastic Agents, Hormonal/pharmacology , Breast Neoplasms/genetics , Drug Resistance, Neoplasm/genetics , MicroRNAs/metabolism , Tamoxifen/pharmacology , 3' Untranslated Regions/genetics , Apoptosis/drug effects , Apoptosis/genetics , Blotting, Northern , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/genetics , Humans , In Situ Hybridization , MicroRNAs/genetics , Oligonucleotide Array Sequence Analysis , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The HER4 intracellular domain (4ICD) is a potent estrogen receptor (ERalpha) coactivator with activities in breast cancer and the developing mammary gland that appear to overlap with progesterone receptor (PgR). In fact, 4ICD has recently emerged as an important regulator and predictor of tamoxifen response, a role previously thought to be fulfilled by PgR. Here we investigated the possibility that the 4ICD coactivator regulates PgR expression thereby providing a mechanistic explanation for their partially overlapping activities in breast cancer. We show that 4ICD is both sufficient and necessary to potentiate estrogen stimulation of gene expression. Suppression of HER4/4ICD expression in the MCF-7 breast tumor cell line completely eliminated estrogen stimulated expression of PgR. In addition, the HER4/4ICD negative MCF-7 variant, TamR, failed to express PgR in response to estrogen. Reintroduction of wild-type HER4 but not the gamma-secretase processing mutant HER4V673I into the TamR cell line restored PgR expression indicating that 4ICD is an essential PgR coactivator in breast tumor cells. These results were substantiated in vivo using two different physiologically relevant experimental systems. In the mouse mammary gland estrogen regulates expression of PgR-A whereas expression of PgR-B is estrogen independent. Consistent with a role for 4ICD in estrogen regulated PgR expression in vivo, PgR-A, but not PgR-B, expression was abolished in HER4-null mouse mammary glands during pregnancy. Coexpression of PgR and 4ICD is also commonly observed in ERalpha positive breast carcinomas. Using quantitative AQUA IHC technology we found that 4ICD potentiated PgR expression in primary breast tumors and the highest levels of PgR expression required coexpression of ERalpha and the 4ICD coactivator. In summary, our results provide compelling evidence that 4ICD is a physiologically important ERalpha coactivator and 4ICD cooperates with ERalpha to potentiate PgR expression in the normal and malignant breast. We propose that direct coupling of these signaling pathways may have important implications for mammary development, breast carcinogenesis, and patient response to endocrine therapy.
Subject(s)
Breast Neoplasms/genetics , ErbB Receptors/genetics , Estrogen Receptor alpha/genetics , Gene Expression Regulation/genetics , Mammary Glands, Human/metabolism , Receptors, Progesterone/genetics , Animals , Breast Neoplasms/metabolism , Cell Line, Tumor , ErbB Receptors/metabolism , Estrogen Receptor alpha/metabolism , Female , Gene Expression , Humans , Mammary Glands, Animal/metabolism , Mice , Mice, Transgenic , Pregnancy , Receptor, ErbB-4 , Receptors, Progesterone/biosynthesis , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/geneticsABSTRACT
Splenic artery aneurysm is a rare disorder (0.7%) that arises mainly as a sequlae to portal hypertension. Other causes of splenic artery aneurysm are atherosclerosis, arterial wall injury due to trauma, pancreatitis, and medial dysplasias of the wall. However, though Caroli's disease is known to cause portal hypertension, the rise of vascular pressure leading to aneurysm is not yet reported (extensive Medlar search failed to reveal any publication). Every effort should be made to diagnose this condition as early as possible because 25% of ruptured splenic aneurysms are fatal. A unique case of Caroli's disease giving rise to splenic artery aneurysm and its possible pathogenesis is reported.
Subject(s)
Aneurysm/etiology , Caroli Disease/complications , Splenic Artery , Aneurysm/diagnosis , Humans , Male , Young AdultABSTRACT
Molecular testing of EGFR is required to predict the response likelihood to targeted therapy in non-small cell lung cancer. Analysis of circulating tumor DNA in plasma may complement limitations of tumor tissue. This study evaluated the interlaboratory performance and reproducibility of a real-time PCR EGFR mutation test (cobas EGFR Mutation Test v2) to detect EGFR variants in plasma. Fourteen laboratories received two identical panels of 27 single-blinded plasma samples. Samples were wild type or spiked with plasmid DNA to contain seven common EGFR variants at six predefined concentrations from 50 to 5000 copies per milliliter. The circulating tumor DNA was extracted by a cell-free circulating DNA sample preparation kit (cobas cfDNA Sample Preparation Kit), followed by duplicate analysis with the real-time PCR EGFR mutation test (Roche Molecular Systems, Pleasanton, CA). Lowest sensitivities were obtained for the c.2156G>C p.(Gly719Ala) and c.2573T>G p.(Leu858Arg) variants for the lowest target copies. For all other variants, sensitivities varied between 96.3% and 100.0%. All specificities were 98.8% to 100.0%. Coefficients of variation indicated good intralaboratory and interlaboratory repeatability and reproducibility but increased for decreasing concentrations. Prediction models revealed a significant correlation for all variants between the predefined copy number and the observed semiquantitative index values, which reflect the samples' plasma mutation load. This study demonstrates an overall robust performance of the real-time PCR EGFR mutation test kit in plasma. Prediction models may be applied to estimate the plasma mutation load for diagnostic or research purposes.
Subject(s)
Mutation/genetics , Real-Time Polymerase Chain Reaction/methods , Algorithms , Bias , Circulating Tumor DNA/blood , Circulating Tumor DNA/genetics , ErbB Receptors/blood , ErbB Receptors/genetics , Europe , Gene Dosage , Humans , Models, Genetic , Sensitivity and SpecificityABSTRACT
BACKGROUND: Transcriptional silencing associated with aberrant promoter methylation has been established as an alternate pathway for the development of cancer by inactivating tumor suppressor genes. TMS1 (Target of Methylation induced Silencing), also known as ASC (Apoptosis Speck like protein containing a CARD) is a tumor suppressor gene which encodes for a CARD (caspase recruitment domain) containing regulatory protein and has been shown to promote apoptosis directly and by activation of downstream caspases. This study describes the methylation induced silencing of TMS1/ASC gene in prostate cancer cell lines. We also examined the prevalence of TMS1/ASC gene methylation in prostate cancer tissue samples in an effort to correlate race and clinico-pathological features with TMS1/ASC gene methylation. RESULTS: Loss of TMS1/ASC gene expression associated with complete methylation of the promoter region was observed in LNCaP cells. Gene expression was restored by a demethylating agent, 5-aza-2'deoxycytidine, but not by a histone deacetylase inhibitor, Trichostatin A. Chromatin Immunoprecipitation (ChIP) assay showed enrichment of MBD3 (methyl binding domain protein 3) to a higher degree than commonly associated MBDs and MeCP2. We evaluated the methylation pattern in 66 prostate cancer and 34 benign prostatic hyperplasia tissue samples. TMS1/ASC gene methylation was more prevalent in prostate cancer cases than controls in White patients (OR 7.6, p 0.002) while no difference between the cases and controls was seen in Black patients (OR 1.1, p 0.91). CONCLUSION: Our study demonstrates that methylation-mediated silencing of TMS1/ASC is a frequent event in prostate cancer, thus identifying a new potential diagnostic and prognostic marker for the treatment of the disease. Racial differences in TMS1/ASC methylation patterns implicate the probable role of molecular markers in determining in susceptibility to prostate cancer in different ethnic groups.
Subject(s)
Cytoskeletal Proteins/genetics , DNA Methylation , Gene Silencing , Prostatic Neoplasms/genetics , Aged , Aged, 80 and over , Azacitidine/analogs & derivatives , Azacitidine/pharmacology , CARD Signaling Adaptor Proteins , Cell Line, Tumor , Chromatin Immunoprecipitation , CpG Islands/genetics , DNA Modification Methylases/antagonists & inhibitors , DNA, Neoplasm/genetics , DNA, Neoplasm/metabolism , Decitabine , Enzyme Inhibitors/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/genetics , Histone Deacetylase Inhibitors , Humans , Hydroxamic Acids/pharmacology , Male , Middle Aged , Promoter Regions, Genetic/genetics , Prostatic Hyperplasia/genetics , Prostatic Hyperplasia/pathology , Prostatic Neoplasms/pathology , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
DNA methylation is an important regulator of gene transcription, and its role in carcinogenesis has been a topic of considerable interest in the last few years. Alterations in DNA methylation are common in a variety of tumors as well as in development. Of all epigenetic modifications, hypermethylation, which represses transcription of the promoter regions of tumor suppressor genes leading to gene silencing, has been most extensively studied. However, global hypomethylation has also been recognized as a cause of oncogenesis. New information concerning the mechanism of methylation and its control has led to the discovery of many regulatory proteins and enzymes. The contribution of dietary folate and methylene terahydrofolate reductase polymorphisms to methylation patterns in normal and cancer tissues is under intense investigation. As methylation occurs early and can be detected in body fluids, it may be of potential use in early detection of tumors and for determining the prognosis. Because DNA methylation is reversible, drugs like 5'-azacytidine, decitabine, and histone deacetylase inhibitors are being used to treat a variety of tumors. Novel demethylating agents such as antisense DNA methyl transferase and small interference RNA are being developed, making the field of DNA methylation wider and more exciting.
Subject(s)
Cell Transformation, Neoplastic , DNA Methylation , Gene Expression Regulation, Neoplastic , Neoplasms/genetics , Neoplasms/physiopathology , Antineoplastic Agents/pharmacology , Genetic Markers , Humans , Prognosis , Risk FactorsABSTRACT
Inactivation of tumor suppressor genes by promoter methylation is an important mechanism of tumorigenesis. Increased expression of DNA methyltransferases has been commonly observed in cancer. A C/T polymorphism in the DNA methyltransferase 3b (DNMT3b) promoter region results in increased activity and has recently been identified as a risk factor for lung cancer. In this study, we examined the C/T polymorphism of the DNMT3b gene in specimens from 81 patients with prostate cancer and 42 controls selected from patients with benign prostatic hypertrophy (BPH). Genomic DNA was isolated from archived formaldehyde-fixed and paraffin-embedded tissue blocks. DNMT3b genotypes were determined by restriction-fragment-length-polymorphism polymerase chain reaction. The DNMT3b polymorphism frequencies in the prostate cancer and BPH specimens were, respectively, 20 and 26% for CC, 42 and 52% for CT, and 38 and 21% for TT. Although such differences fall within the realm of chance variation (P>0.05), the data suggest that the TT genotype may be associated with an increased risk of prostate cancer: the age-adjusted odds ratio (aOR) was 2.6 [95% confidence interval: 0.8-8.0]; the increase in odds ratio was seen in both blacks and whites (aOR=4.3 in blacks, and 2.0 in whites). The samples used in this study have previously been examined for methylation index (MI) based on the number of genes methylated, the range being 0 to 5. A trend toward an increase in MI was detected for the DNMT3b polymorphisms in prostate cancer patients but not for BPH subjects (mean MI 2.6, 2.9, 3.1 for CC, CT, and TT genotype in prostate cancer; 0.8, 0.8, 0.7 for CC, CT, and TT genotype in BPH subjects). These findings suggest that the DNMT3b polymorphisms may be associated with an increase in promoter methylation of tumor-suppressor genes related to the development of prostate cancer, and may thereby increase the risk of this disease.
Subject(s)
DNA (Cytosine-5-)-Methyltransferases/genetics , Polymorphism, Single Nucleotide , Prostatic Neoplasms/pathology , Black or African American/genetics , Aged , Aged, 80 and over , Cadherins/genetics , DNA Methylation , DNA, Neoplasm/genetics , DNA, Neoplasm/metabolism , Gene Frequency , Genotype , Glutathione S-Transferase pi , Glutathione Transferase/genetics , Humans , Hyaluronan Receptors/genetics , Isoenzymes/genetics , Logistic Models , Male , Middle Aged , Odds Ratio , Prostatic Hyperplasia/ethnology , Prostatic Hyperplasia/genetics , Prostatic Hyperplasia/pathology , Prostatic Neoplasms/ethnology , Prostatic Neoplasms/genetics , Receptor, Endothelin B/genetics , Receptors, Retinoic Acid/genetics , Risk Factors , Tumor Suppressor Proteins/genetics , White People/genetics , DNA Methyltransferase 3BABSTRACT
Association between proteins and DNA is crucial for many vital cellular functions such as gene transcription, DNA replication and recombination, repair, segregation, chromosomal stability, cell cycle progression, and epigenetic silencing. It is important to know the genomic targets of DNA-binding proteins and the mechanisms by which they control and guide gene regulation pathways and cellular proliferation. Chromatin immunoprecipitation (ChIP) is an important technique in the study of protein-gene interactions. Using ChIP, DNA-protein interactions are studied within the context of the cell. The basic steps in this technique are fixation, sonication, immunoprecipitation, and analysis of the immunoprecipitated DNA. Although ChIP is a very versatile tool, the procedure requires the optimization of reaction conditions. Several modifications to the original ChIP technique have been published to improve the success and to enhance the utility of this procedure. This review addresses the critical parameters and the variants of ChiP as well as the different analytical tools that can be combined with ChIP to enable better understanding of DNA-protein interactions in vivo.
Subject(s)
Chromatin Immunoprecipitation/instrumentation , Chromatin Immunoprecipitation/methods , DNA-Binding Proteins/analysis , DNA-Binding Proteins/metabolism , DNA/analysis , DNA/metabolism , Chromatin Immunoprecipitation/trendsABSTRACT
Methylenetetrahydrofolate reductase (MTHFR) catalyzes the synthesis of 5-methyltetrahydrofolate, which is involved in the methylation of homocysteine to methionine. Genetic polymorphisms that decrease MTHFR activity result in an altered cancer risk depending on folic acid intake. In this study we examined the C677T and A1298C polymorphisms of the MTHFR gene in specimens from 81 patients with prostate cancer and 42 controls selected from patients with benign prostatic hypertrophy (BPH). Genomic DNA was isolated from archived formaldehyde-fixed and paraffin-embedded tissue blocks. MTHFR genotypes were determined by restriction-fragment-length-polymorphism polymerase chain reaction. The MTHFR polymorphism frequencies in the prostate-cancer and BPH specimens were, respectively, 60% and 48% for 677CC, 31% and 48% for 677CT, 9% and 5% for 677TT, 36% and 43% for 1298AA, 53% and 40% for 1298AC, and 11% and 17% for 1298CC. Although such differences fall within the realm of chance variation (P>0.05), the data suggest that the 677CT genotype may be associated with a reduced risk of prostate cancer: the age-adjusted odds ratio (aOR) was 0.6 [95% confidence interval (CI): 0.3-1.4]; the odds-ratio reduction was similar in both blacks and whites (aOR=0.4 in blacks, and 0.6 in whites); and when polymorphisms at the 677 and 1298 loci were analyzed in conjunction, a lower frequency of the 677CT-1298AA genotype was observed in the patients with prostate cancer (aOR=0.3, 95% CI: 0.1-1.1). This particular genotype, moreover, was associated with lower Gleason score tumors (aOR=0.1 for Gleason-score 7 versus 6 tumors, 95% CI: 0.0-0.7) and earlier stage disease (aOR=0.3 for stage III versus II, 95% CI: 0.3-2.6). These findings suggest that polymorphisms of the MTHFR gene may alter the risk of developing prostate cancer.
Subject(s)
Genetic Predisposition to Disease , Methylenetetrahydrofolate Reductase (NADPH2)/genetics , Polymorphism, Genetic , Prostatic Neoplasms/etiology , Prostatic Neoplasms/genetics , Aged , Aged, 80 and over , Case-Control Studies , Humans , Male , Middle Aged , Odds Ratio , Prostatic Hyperplasia/genetics , Risk FactorsABSTRACT
Three cases of melanoma of the soft parts diagnosed by aspiration cytology and immunochemistry are described. Unusual clinicoradiological features, variable cytomorphology, absence of melanin, and lack of awareness due to rarity of the lesion caused diagnostic dilemma. Morphological similarity to alveolar soft part sarcoma, synovial and epithelioid sarcoma, cutaneous melanoma, poorly differentiated carcinoma, and plasmacytoma were noted. Consideration of clinical data such as age, site, and radiology was helpful in narrowing down the diagnosis. A presumptive cytologic diagnosis helped in selecting the antibody panel, which established the definitive diagnosis in all cases. This approach is valuable in preoperative management and obviates the need for an open biopsy in primary, metastatic, or recurrent tumor. Increasing experience in fine-needle aspiration of this rare entity and correlation with immunochemistry and histopathology are valuable in narrowing down the differential diagnosis, reducing diagnostic errors, and widening its clinicocytological spectrum.
Subject(s)
Biopsy, Needle/methods , Neoplasm Recurrence, Local/pathology , Sarcoma, Clear Cell/secondary , Soft Tissue Neoplasms/pathology , Adult , Biomarkers, Tumor/analysis , Carcinoma/pathology , Diagnosis, Differential , Female , Humans , Immunohistochemistry , Male , Middle Aged , Neoplasm Metastasis/pathology , Neoplasm Recurrence, Local/chemistry , Neoplasm Recurrence, Local/surgery , Periodic Acid-Schiff Reaction , Plasmacytoma/pathology , Sarcoma/pathology , Sarcoma, Clear Cell/chemistry , Sarcoma, Clear Cell/surgery , Soft Tissue Neoplasms/chemistry , Soft Tissue Neoplasms/surgeryABSTRACT
The NRG1 growth factor and ERBB4 receptor have been identified as leading schizophrenia risk genes. Although NRG1 and ERBB4 have been shown to modulate neuronal functions involved in schizophrenia, including both GABAergic and glutamatergic synapses, the exact molecular mechanisms remain poorly understood. Here we investigated ERBB4 intracellular domain, 4ICD, transactivator function in rat hippocampal cultures by inhibiting γ-secretase mediated ERBB4 regulated intramembrane proteolysis (RIP). NRG1 stimulation resulted in a dramatic increase in the number of hippocampal cells displaying nuclear 4ICD which was abolished in cultures pretreated with the γ-secretase inhibitor compound E (CE). To identify NRG1-4ICD transactivated genes we compared global gene expression profiles of hippocampal cultures stimulated with NRG1 in the absence or presence of CE. In concordance with the contribution of NRG1-ERBB4 signaling to dendritic spine maturation and schizophrenia, global gene expression analysis followed by Ingenuity Pathway Analysis of the dataset identified NRG1-4ICD regulated genes significantly represented in semaphorin signaling and actin cytoskeletal plasticity and multiple genes with confirmed roles in dendritic spine morphogenesis. Using the power of global gene expression analysis our data provides a proof-of-concept supporting a role for non-canonical NRG1-4ICD signaling in the regulation of gene expression contributing to normal and schizophrenic neuronal function.
Subject(s)
ErbB Receptors/physiology , Gene Expression Regulation/physiology , Hippocampus/physiology , Intracellular Fluid/physiology , Neuregulin-1/physiology , Neurons/physiology , Animals , Cell Differentiation/genetics , Cells, Cultured , ErbB Receptors/chemistry , ErbB Receptors/genetics , Female , Gene Expression Profiling/methods , Hippocampus/pathology , Neuregulin-1/agonists , Neuregulin-1/genetics , Neuronal Plasticity/genetics , Neurons/cytology , Neurons/pathology , Protein Structure, Tertiary/genetics , Rats , Rats, Sprague-Dawley , Receptor, ErbB-4 , Schizophrenia/genetics , Schizophrenia/metabolism , Schizophrenia/pathology , Signal Transduction/geneticsABSTRACT
Ovarian cancer is associated with an overall mortality of 75%, but can be cured in up to 90% of cases if diagnosed while still limited to the ovaries. Given the low prevalence of ovarian cancer in the general population, an effective screening strategy must not only have a high sensitivity for early-stage disease (>75%), but must also have a very high specificity (99.6%) to prompt no more than ten operations for each case of ovarian cancer diagnosed (positive predictive value [PPV] of 10%). Attempts to develop an effective screening strategy for ovarian cancer have utilized ultrasonography and serum tumor markers. Transvaginal sonography (TVS) and the serum marker CA125 have received the most attention to date. Used individually on a single occasion, neither of these approaches provides an adequate PPV and the cost of annual TVS is significant. Recent clinical trials have focused on serial monitoring of CA125 and the sequential use of a rising CA125 to prompt TVS in a limited number of women screened. Sequential monitoring of CA125 has significantly improved specificity of the assay in women over 50 years of age. The limited sensitivity of CA125 has, however, prompted a search for multiple serum markers that, in combination, would detect more than 90% of early-stage disease. Recent developments in genomic and proteomic research have identified a number of candidate biomarkers. Platforms have been developed that can assay more than 50 analytes in a few hundred microliters of serum. Panels of biomarkers have been discovered with high sensitivity and specificity for early-stage disease, but these require prospective validation. Several biomarkers have also been detected in urine, raising the possibility of a less expensive, more convenient screening test. Imaging techniques have been improved and mathematical methods developed that, in aggregate, promise to provide an effective screening strategy for ovarian cancer. In this review, we will assess the current status and describe future directions in ovarian cancer screening.