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1.
Transl Oncol ; 17: 101350, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35091340

ABSTRACT

The molecular implications of food consumption on cancer etiology are poorly defined. The rate of nutrition associated non-enzymatic glycoxidation, a reaction that occurs between reactive carbonyl groups on linear sugars and nucleophilic amino, lysyl and arginyl groups on fats and proteins, is rapidly increased by food cooking and manufacturing processes. In this study, we assign nutrition-associated glycoxidation with significant oncogenic potential, promoting prostate tumor growth, progression, and metastasis in vivo. Advanced glycation end products (AGEs) are the final irreversible product of non-enzymatic glycoxidation. Exogenous treatment of prostate tumor cells with a single AGE peptide replicated glycoxidation induced tumor growth in vivo. Mechanistically, receptor for AGE (RAGE) deficiency in the stroma inhibited AGE mediated tumor growth. Functionally, AGE treatment induced RAGE dimerization in activated fibroblasts which sustained and increased the migratory potential of tumor epithelial cells. These data identify a novel nutrition associated pathway that can promote a tissue microenvironment conducive for aggressive tumor growth. Targeted and/or interventional strategies aimed at reducing AGE bioavailability as a consequence of nutrition may be viewed as novel chemoprevention initiatives.

2.
Arch Pathol Lab Med ; 144(7): 878-882, 2020 07 01.
Article in English | MEDLINE | ID: mdl-31846366

ABSTRACT

CONTEXT.­: Social media sites are increasingly used for education, networking, and rapid dissemination of medical information, but their utility for facilitating research has remained largely untapped. OBJECTIVE.­: To describe in detail our experience using a social media platform (Twitter) for the successful initiation, coordination, and completion of an international, multi-institution pathology research study. DESIGN.­: Following a tweet describing a hitherto-unreported biopsy-related histologic finding in a mediastinal lymph node following endobronchial ultrasound-guided transbronchial needle aspiration, a tweet was posted to invite pathologists to participate in a validation study. Twitter's direct messaging feature was used to create a group to facilitate communication among participating pathologists. Contributing pathologists reviewed consecutive cases of mediastinal lymph node resection following endobronchial ultrasound-guided transbronchial needle aspiration and examined them specifically for biopsy site changes. Data spreadsheets containing deidentified data and digital photomicrographs of suspected biopsy site changes were submitted via an online file hosting service for central review by 5 pathologists from different institutions. RESULTS.­: A total of 24 pathologists from 14 institutions in 5 countries participated in the study within 143 days of study conception, and a total of 297 cases were collected and analyzed. The time interval between study conception and acceptance of the manuscript for publication was 346 days. CONCLUSIONS.­: To our knowledge, this is the first time that a social media platform has been used to generate a research idea based on a tweet, recruit coinvestigators publicly, communicate with collaborating pathologists, and successfully complete a pathology study.


Subject(s)
Adenocarcinoma of Lung/pathology , Biomedical Research , Endoscopic Ultrasound-Guided Fine Needle Aspiration/adverse effects , Lung Neoplasms/pathology , Lymph Nodes/pathology , Research Design , Scholarly Communication , Social Media , Adenocarcinoma of Lung/therapy , Cooperative Behavior , Fibrosis , Humans , International Cooperation , Lung Neoplasms/therapy , Mediastinum , Predictive Value of Tests , Workflow
3.
Am J Surg Pathol ; 43(4): 497-503, 2019 04.
Article in English | MEDLINE | ID: mdl-30475256

ABSTRACT

Biopsy site changes in mediastinal lymph nodes (LNs) attributable to prior endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) have not been studied in a systematic manner. Twenty-four contributors from 14 institutions in 5 countries collaborated via social media (Twitter) to retrospectively review consecutive cases of resected mediastinal LNs from patients with prior EBUS-TBNA. Resected LNs were reexamined by submitting pathologists for changes attributable to EBUS-TBNA. Patients who received neoadjuvant therapy were excluded. Cases with suspected biopsy site changes underwent central review by 5 pathologists. A total of 297 mediastinal LN resection specimens from 297 patients (183 male/114 female, mean age: 65 y, range: 23 to 87) were reviewed. Biopsy site changes were most common in station 7 (10 cases) followed by 11R, 4R, and 10R, and were found in 34/297 (11.4%) cases, including displacement of tiny cartilage fragments into LN parenchyma in 26, intranodal or perinodal scars in 7, and hemosiderin in 1. Cartilage fragments ranged from 0.26 to 1.03 mm in length and 0.18 to 0.62 mm in width. The mean interval between EBUS-TBNA and LN resection was 38 days (range: 10 to 112) in cases with biopsy site changes. A control group of 40 cases without prior EBUS-TBNA, including 193 mediastinal LN stations, showed no evidence of biopsy site changes. Biopsy site changes are identified in a subset of resected mediastinal LNs previously sampled by EBUS-TBNA. The location of the abnormalities, temporal association with prior EBUS-TBNA, and the absence of such findings in cases without prior EBUS-TBNA support the contention that they are caused by EBUS-TBNA.


Subject(s)
Cartilage/pathology , Image-Guided Biopsy/adverse effects , Lymph Node Excision/adverse effects , Lymph Nodes/pathology , Adult , Aged , Aged, 80 and over , Biopsy, Fine-Needle/adverse effects , Biopsy, Fine-Needle/methods , Endosonography/adverse effects , Endosonography/methods , Female , Humans , Image-Guided Biopsy/methods , Lymph Node Excision/methods , Male , Mediastinum , Middle Aged , Retrospective Studies , Ultrasonography, Interventional/adverse effects , Ultrasonography, Interventional/methods , Young Adult
4.
Ann Surg Oncol ; 25(10): 2953-2957, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29971672

ABSTRACT

BACKGROUND: This study aimed to investigate the changes in diagnosis after a second opinion for breast cancer patients from a multi-disciplinary tumor board (MTB) review at an National Cancer Institute (NCI)-designated cancer center. METHODS: A retrospective study analyzed patients with a breast cancer diagnosed at an outside institution who presented for a second opinion from August 2015 to March 2016 at the Medical University of South Carolina (MUSC). Radiology, pathology, and genetic testing reports from outside institutions were compared with reports generated after an MTB review and subsequent workup at MUSC. The second-opinion cases were categorized based on whether diagnostic variations were present or not. RESULTS: The review included 70 patients seeking second opinions, and 33 (47.1%) of these patients had additional radiologic images. A total of 30 additional biopsies were performed for 25 patients, with new cancers identified in 16 patients. Overall, 16 (22.8%) of the 70 of patients had additional cancers diagnosed. For 14 (20%) of the 70 patients, a second opinion led to a change in pathology interpretation. Genetic testing was performed for 11 patients (15.7%) who met the National Comprehensive Cancer Network (NCCN) guidelines for genetic testing, but none showed a mutation other than a variant of unknown significance. After a complete workup, 30 (42.8%) of the 70 patients had a change in diagnosis as a result of the MTB review. CONCLUSION: A review by an MTB at an NCI-designated cancer center changed the diagnosis for 43% of the patients who presented for a second opinion for breast cancer. The study findings support the conclusion that referral for a second opinion is beneficial and has a diagnostic impact for many patients.


Subject(s)
Breast Neoplasms/pathology , Cancer Care Facilities , Carcinoma in Situ/pathology , Diagnostic Errors/prevention & control , Observer Variation , Referral and Consultation/statistics & numerical data , Biopsy , Female , Follow-Up Studies , Genetic Testing , Humans , National Cancer Institute (U.S.) , Neoplasm Invasiveness , Radiology , Retrospective Studies , United States
5.
Breast Cancer Res Treat ; 164(2): 349-358, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28484924

ABSTRACT

PURPOSE: NSD3 has been implicated as a candidate driver oncogene from the 8p11-p12 locus, and we have previously published evidence for its amplification and overexpression in human breast cancer. This aim of this study was to further characterize the transforming function of NSD3 in vivo. METHODS: We generated a transgenic mouse model in which NSD3 gene expression was driven by the MMTV promoter and expressed in mammary epithelium of FVB mice. Mammary glands were fixed and whole mounts were stained with carmine to visualize gland structure. Mammary tumors were formalin-fixed, and paraffin embedded (FFPE) tumors were stained with hematoxylin and eosin. RESULTS: Pups born to transgenic females were significantly underdeveloped compared to pups born to WT females due to a lactation defect in transgenic female mice. Whole mount analysis of the mammary glands of transgenic female mice revealed a profound defect in functional differentiation of mammary gland alveoli that resulted in the lactation defect. We followed parous and virgin NSD3 transgenic and control mice to 50 weeks of age and observed that several NSD3 parous females developed mammary tumors. Whole mount analysis of the mammary glands of tumor-bearing mice revealed numerous areas of mammary hyperplasia and ductal dysplasia. Histological analysis showed that mammary tumors were high-grade ductal carcinomas, and lesions present in other mammary glands exhibited features of alveolar hyperplasia, ductal dysplasia, and carcinoma in situ. CONCLUSIONS: Our results are consistent with our previous studies and demonstrate that NSD3 is a transforming breast cancer oncogene.


Subject(s)
Carcinoma, Ductal, Breast/pathology , Cell Transformation, Neoplastic/pathology , Histone-Lysine N-Methyltransferase/genetics , Mammary Neoplasms, Experimental/pathology , Nuclear Proteins/genetics , Animals , Carcinoma, Ductal, Breast/genetics , Cell Transformation, Neoplastic/genetics , Female , Humans , Hyperplasia , Lactation , Mammary Neoplasms, Experimental/genetics , Mice , Mice, Transgenic , Neoplasm Grading , Promoter Regions, Genetic
6.
Int J Surg Pathol ; 25(4): 352-356, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28112042

ABSTRACT

This report highlights a diagnostically challenging case of diffuse deciduoid mesothelioma occurring in the peritoneum of a 25-year-old woman, 8 months postpartum. Optimally debulked tumor consisted of sheets of polygonal cells arranged in solid, trabecular, and pseudopapillary configurations, with vesicular, occasionally grooved nuclei and small nucleoli. A barrage of immunohistochemical stains revealed an unusual staining pattern characterized by diffusely positive keratin, WT-1, and mesothelin staining, but lack of calretinin positivity. Electron microscopy demonstrated only rare thin, long, branching cellular projections. Cytogenetics revealed balanced translocations of 12p and 1q and 16p. Based on compiled ancillary studies, a diagnosis of deciduoid mesolthelioma was made and supported by consultations from experts at 3 outside facilities. Twenty-seven months after diagnosis, the patient is alive and undergoing treatment with progression of disease. This case is presented in detail, and a discussion of the diagnostic criteria and current application of those criteria is provided.


Subject(s)
Mesothelioma/pathology , Peritoneal Neoplasms/pathology , Adult , Female , Humans
7.
Int J Gynecol Pathol ; 36(6): 540-549, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28114190

ABSTRACT

African American (AA) females with endometrial carcinoma have a significantly worse prognosis with regard to disease-free survival and overall survival than their European American (EA) counterparts and this finding is true across all stages and grades. The presence of tumor-infiltrating lymphocytes (TILs) has been demonstrated to be of prognostic significance in a variety of malignancies, including endometrial cancers. This study aims to determine whether clinically significant differences in levels of CD8+ cytotoxic T lymphocytes, FoxP3+ regulatory T lymphocytes, and CD45RO+ memory T lymphocytes exist between races and to document the clinical impact of TILs. One hundred ten patients with endometrial adenocarcinoma, treated with hysterectomy from 2003 to 2011 were studied. Patients were selected to provide equal representation across type and grade for both EAs and AAs. Immunohistochemical stains were used to highlight CD8-positive, FoxP3-positive, and CD45RO-positive TILs at the endometrial-myometrial interface on slides from paraffin-embedded tissue. Patients with "high" or "low" levels of TILs were compared with respect to the race, tumor type, and survival. High levels of CD45RO+ TILs were associated with improved overall survival in EA women (hazard ratio, 0.32; 95% confidence interval, 0.11-0.92; P=0.034). Comparatively, AA women with high levels of CD45RO+ TILs received no survival benefit (hazard ratio, 0.96; 95% confidence interval, 0.35-2.64; P=0.94). High levels of CD8-positive or FoxP3-positive TILs, alone, had no impact on survival. EA patients with TILs containing high levels of CD45RO cells but low levels of CD8+ cells lost the survival benefit; however, limited numbers preclude significant conclusions from this observation. Neither tumor type nor race were predictive of the levels of TILs of any type. Further study with a larger sample size is required to determine the impact of TIL subtype combinations on survival.


Subject(s)
Endometrial Neoplasms/diagnosis , Black or African American , CD8 Antigens/metabolism , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/pathology , Disease-Free Survival , Endometrial Neoplasms/metabolism , Endometrial Neoplasms/pathology , Female , Forkhead Transcription Factors/metabolism , Humans , Leukocyte Common Antigens/metabolism , Lymphocytes, Tumor-Infiltrating/metabolism , Lymphocytes, Tumor-Infiltrating/pathology , Middle Aged , Prognosis , Proportional Hazards Models , United States/ethnology , White People
10.
BJU Int ; 115 Suppl 6: 8-15, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25597776

ABSTRACT

OBJECTIVES: To develop a urodynamic model incorporating external urethral sphincter (EUS) electromyography (EMG) in awake rats. MATERIALS AND METHODS: Bladder catheters and EUS EMG electrodes were implanted in female Sprague Dawley rats. Assessments were performed in awake, lightly restrained rats on postoperative day 12-14. Measurements were repeated in the same rat on day 16 under urethane anaesthesia. Urodynamics and EUS EMG were performed simultaneously. In addition, serum creatinine and bladder histology was assessed. RESULTS: No significant differences in urodynamic parameters were found between bladder catheter only vs bladder catheter and EUS EMG electrode groups. Urethane anaesthesia evoked prominent changes in both urodynamic parameters and EUS EMG. Serum creatinine was within the normal limits in all rats. Bladder weight and bladder wall thickness were significantly increased in both the bladder catheter only and the bladder catheter and EUS EMG group compared with controls. CONCLUSIONS: Our novel urodynamic model allows repetitive measurements of both bladder and EUS function at different time points in the same rat under fully awake conditions and opens promising avenues to investigate lower urinary tract dysfunction in a translational approach.


Subject(s)
Models, Animal , Urethra/physiology , Urodynamics/physiology , Anesthetics, Intravenous/pharmacology , Animals , Electromyography , Female , Muscle Contraction/physiology , Pressure , Rats, Sprague-Dawley , Urethane/pharmacology , Urination/physiology
12.
Head Neck ; 36(3): 393-400, 2014 Mar.
Article in English | MEDLINE | ID: mdl-23728920

ABSTRACT

BACKGROUND: Liposarcomas are rare in the head and neck. We analyzed a large series of head and neck liposarcomas to determine features unique to the head and neck. METHODS: Three hundred eighteen liposarcomas of the head and neck were contrasted with 9485 liposarcomas of other regions using the Surveillance, Epidemiology, and End Results (SEER) database. RESULTS: Head and neck liposarcomas were most commonly subcutaneous (81.%), low grade (70.1%; p < .001), and early stage (p < .001). They were more likely to be treated with surgery alone, whereas conventional liposarcomas were more likely to receive adjuvant radiation (p < .001). Treatment that included surgery had better survival than radiation therapy alone (p = .008). Overall, liposarcomas of the head and neck had significantly higher disease-specific survival (DSS) and overall survival (OS) than conventional liposarcomas (p < .001). CONCLUSION: Liposarcomas of the head and neck are usually early stage, low grade, and with fewer nodal metastases than conventional liposarcomas. DSS and OS were significantly greater for liposarcomas of the head and neck.


Subject(s)
Head and Neck Neoplasms/mortality , Head and Neck Neoplasms/pathology , Liposarcoma/mortality , Liposarcoma/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Head and Neck Neoplasms/radiotherapy , Humans , Kaplan-Meier Estimate , Liposarcoma/radiotherapy , Male , Middle Aged , Neoplasm Staging , Prognosis , Radiotherapy, Adjuvant , Young Adult
13.
Am J Physiol Renal Physiol ; 306(3): F299-308, 2014 Feb 01.
Article in English | MEDLINE | ID: mdl-24285499

ABSTRACT

Bladder inflammation (cystitis) underlies numerous bladder pathologies and is elicited by a plethora of agents such as urinary tract infections, bladder outlet obstruction, chemotherapies, and catheters. Pattern recognition receptors [Toll-like receptors (TLRs) and Nod-like receptors (NLRs)] that recognize pathogen- and/or damage-associated molecular patterns (PAMPs and/or DAMPs, respectively) are key components of the innate immune system that coordinates the production (TLRs) and maturation (NLRs) of proinflammatory IL-1ß. Despite multiple studies of TLRs in the bladder, none have investigated NLRs beyond one small survey. We now demonstrate that NLRP3 and NLRC4, and their binding partners apoptosis-associated speck-like protein containing a COOH-terminal caspase recruitment domain (ASC) and NLR family apoptosis inhibitory protein (NAIP), are expressed in the bladder and localized predominantly to the urothelia. Activated NLRs form inflammasomes that activate caspase-1. Placement of a NLRP3- or NLRC4-activating PAMP or NLRP3-activating DAMPs into the lumen of the bladder stimulated caspase-1 activity. To investigate inflammasomes in vivo, we induced cystitis with cyclophosphamide (CP, 150 mg/kg ip) in the presence or absence of the inflammasome inhibitor glyburide. Glyburide completely blocked CP-induced activation of caspase-1 and the production of IL-1ß at 4 h. At 24 h, glyburide reduced two markers of inflammation by 30-50% and reversed much of the inflammatory morphology. Furthermore, glyburide reversed changes in bladder physiology (cystometry) induced by CP. In conclusion, NLRs/inflammasomes are present in the bladder urothelia and respond to DAMPs and PAMPs, whereas NLRP3 inhibition blocks bladder dysfunction in the CP model. The coordinated response of NLRs and TLRs in the urothelia represents a first-line innate defense that may provide an important target for pharmacological intervention.


Subject(s)
Inflammasomes/physiology , Receptors, Cell Surface/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Urinary Bladder/immunology , Animals , Carrier Proteins , Cyclophosphamide , Cystitis/chemically induced , Cystitis/immunology , Female , Glyburide/pharmacology , Immunity, Innate , NLR Family, Pyrin Domain-Containing 3 Protein , Neuronal Apoptosis-Inhibitory Protein/metabolism , Rats , Toll-Like Receptors/immunology
14.
FASEB J ; 23(9): 2879-87, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19417087

ABSTRACT

It has been hypothesized that translational efficiency is determined by the amount of secondary structure in the 5'-untranslated region (5'-UTR) of mRNA. Here, we examined whether specific 5'-UTRs with excessive secondary structure selectively regulate translational efficiency in adult cardiocytes. Recombinant adenoviruses were generated to express reporter mRNAs consisting of the 5'-UTR derived from c-jun or ornithine decarboxylase (ODC) fused to beta-galactosidase (betaGal) coding sequence. Each adenovirus expressed GFP mRNA as a control for 5'-UTRs with minimal secondary structure. Subsequently, cardiocytes were electrically stimulated to contract at 1 Hz to accelerate protein synthesis as compared to quiescent controls. Translational efficiency was calculated by measuring protein expression as a function of mRNA levels. Translational efficiency of c-jun/betaGal mRNA increased significantly by 3.7-fold in contracting vs. quiescent cardiocytes, but ODC/betaGal mRNA was unchanged. Contraction increased c-jun/betaGal mRNA levels in polyribosomes by 2.3-fold, which indicates that translational efficiency was enhanced by mobilization. A short, unstructured 5'-UTR was sufficient for efficient translation of betaGal mRNA in quiescent and contracting cardiocytes. GFP mRNA produced similar results. These studies demonstrate that the 5'-UTR functions as a determinant of translational efficiency of specific mRNAs, such as c-jun, that regulate growth of the adult cardiocyte.


Subject(s)
5' Untranslated Regions/genetics , Protein Biosynthesis , RNA, Messenger/analysis , Adenoviridae/genetics , Animals , Cats , Cell Proliferation , Myocytes, Cardiac/cytology , Proto-Oncogene Proteins c-jun/genetics , Transduction, Genetic
15.
J Mol Cell Cardiol ; 44(1): 69-75, 2008 Jan.
Article in English | MEDLINE | ID: mdl-18036610

ABSTRACT

During pressure overload hypertrophy, selective changes in cardiac gene expression occur that regulate growth and modify the structural and functional properties of the myocardium. To determine the role of translational mechanisms, a murine model of transverse aortic constriction was used to screen a set of specified mRNAs for changes in translational activity by measuring incorporation into polysomes in response to acute pressure overload. Candidate mRNAs were selected on the basis of two main criteria: (1) the 5'-untranslated region of the mRNA contains an excessive amount of secondary structure (DeltaG<-50 kCal/mol), which is postulated to regulate efficiency of translation, and (2) the protein product has been implicated in the regulation of cardiac hypertrophy. After 24 h of transverse aortic constriction, homogenates derived from the left ventricle were layered onto 15-50% linear sucrose gradients and resolved into monosome fractions (messenger ribonucleoprotein particles) and polysome fractions by density gradient ultracentrifugation. The levels of mRNA in each fraction were quantified by real-time RT-PCR. The screen revealed that pressure overload increased translational activity of 6 candidate mRNAs as determined by a significant increase in the percentage of total mRNA incorporated into the polysome fractions. The mRNAs code for several functional classes of proteins linked to cardiac hypertrophy: the transcription factors c-myc, c-jun and MEF2D, growth factors VEGF and FGF-2 and the E3 ubiquitin ligase MDM2. These studies demonstrate that acute pressure overload alters cardiac gene expression by mechanisms that selectively regulate translational activity of specific mRNAs.


Subject(s)
Heart Ventricles/metabolism , Heart Ventricles/physiopathology , Myocardium/metabolism , Protein Biosynthesis , Ventricular Pressure , Animals , Aorta/pathology , Gene Expression Regulation , Hypertrophy , Mice , Myocardium/pathology , Organ Size , RNA, Messenger/genetics , RNA, Messenger/metabolism , Time Factors , Vasoconstriction
16.
Am J Physiol Cell Physiol ; 293(4): C1362-73, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17670887

ABSTRACT

Past studies have identified that a unique type of matrix metalloproteinase, the membrane-type-1 MMP (MT1-MMP), is increased within the left ventricle (LV) of patients with dilated cardiomyopathy (DCM). However, the cellular and molecular basis for this induction of MT1-MMP with DCM is unknown. LV myocardial biopsies from nonfailing, reference normal patients (defined as LV ejection fraction >50%, elective coronary bypass surgery, no perfusion defect at biopsy site, n = 6) and DCM patients (LV ejection fraction <20%, at transplant, n = 5) were used to establish fibroblast cultures (FIBROS). Confluent LV FIBROS from culture passages 2-5 were measured with respect to MT1-MMP mRNA and protein levels and the distribution of the MT1-MMP mRNA pool in ribosomal fractions. Total MT1-MMP mRNA within DCM FIBROS increased by over 140%, and MT1-MMP protein increased by over 190% from reference normal FIBROS (both P < 0.05). MT1-MMP mRNA in monosome fractions decreased by over twofold in DCM FIBROS compared with reference normal (P < 0.05) and remained lower in polyribosomal fractions (i.e., 15.7 +/- 5.2 vs. 1.4 +/- 0.6% in polysomal fraction 6, P < 0.05). These differences in DCM MT1-MMP FIBROS transcription and translation persisted throughout passages 2-5. The unique findings from this study demonstrated that elevated steady-state MT1-MMP mRNA and protein levels occurred in DCM FIBROS despite a decline in translational deficiency. These phenotypic changes in DCM fibroblasts may provide the basis for developing cell specific pharmacological targets for control of MT1-MMP expression.


Subject(s)
Cardiomyopathy, Dilated/enzymology , Fibroblasts/enzymology , Matrix Metalloproteinase 14/metabolism , Myocardium/enzymology , Adult , Biopsy , Cardiomyopathy, Dilated/genetics , Cardiomyopathy, Dilated/pathology , Cell Membrane/metabolism , Cells, Cultured , Fibroblasts/drug effects , Fibroblasts/metabolism , Humans , Intracellular Space/drug effects , Intracellular Space/metabolism , Kinetics , Matrix Metalloproteinase 14/genetics , Matrix Metalloproteinase 2/metabolism , Microscopy, Confocal , Middle Aged , Myocardium/metabolism , Myocardium/pathology , Polyribosomes/metabolism , Protein Biosynthesis/drug effects , Proto-Oncogene Proteins c-jun/genetics , Proto-Oncogene Proteins c-jun/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transcription, Genetic/drug effects , Tumor Necrosis Factor-alpha/pharmacology , Ventricular Function, Left
17.
FASEB J ; 20(12): 2133-5, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16940435

ABSTRACT

Hypertrophic growth of adult myocardium is associated with increased expression of the early response gene c-jun. The purpose of this study was to determine whether eukaryotic initiation factor (elF) 4E (eIF4E) regulates translational efficiency of c-jun mRNA as measured by flux into polysomes. Adult feline cardiomyocytes in primary culture were treated with 0.2 microM 12-O-tetradecanoylphorbol 13-acetate (TPA), and c-jun mRNA was quantified in total, monosome, and polysome fractions by real-time polymerase chain reaction. After 1 h, TPA increased total c-jun mRNA by 10.5-fold. The corresponding flux into polysomes was significantly lower (5-fold). Adenoviral-mediated overexpression of either eIF4E or a nonphosphorylatable mutant (S209/A) did not affect total c-jun mRNA or its flux between monosomes and polysomes. Similar results were obtained following overexpression of the eIF4E kinase Mnk1. Thus, translational efficiency of c-jun mRNA was not affected by changes in activity or amount of eIF4E. In contrast, a kinase-deficient Mnk1 mutant significantly reduced total c-jun mRNA from 9.8-fold to 6.0-fold while flux between monosomes and polysomes remained constant. The decrease in total c-jun mRNA resulted from increased decay of c-jun mRNA incorporated into the polysomes. We conclude that Mnk1 activity stabilizes c-jun mRNA in polysomes independent of eIF4E phosphorylation.


Subject(s)
Gene Expression Regulation , Intracellular Signaling Peptides and Proteins/physiology , Myocytes, Cardiac/metabolism , Protein Serine-Threonine Kinases/physiology , Proto-Oncogene Proteins c-jun/genetics , RNA, Messenger/genetics , Animals , Cats , Cells, Cultured , Eukaryotic Initiation Factor-4E/metabolism , Polyribosomes/metabolism , RNA Stability
18.
Biochem J ; 378(Pt 1): 73-82, 2004 Feb 15.
Article in English | MEDLINE | ID: mdl-14629199

ABSTRACT

In adult cardiocytes, eIF4E (eukaryotic initiation factor 4E) activity and protein synthesis are increased concomitantly in response to stimuli that induce hypertrophic growth. We tested the hypothesis that increases in eIF4E activity selectively improve the translational efficiency of mRNAs that have an excessive amount of secondary structure in the 5'-UTR (5'-untranslated region). The activity of eIF4E was modified in primary cultures of adult cardiocytes using adenoviral gene transfer to increase either the amount of eIF4E or the extent of endogenous eIF4E phosphorylation. Subsequently, the effects of eIF4E on translational efficiency were assayed following adenoviral-mediated expression of luciferase reporter mRNAs that were either 'stronger' (less structure in the 5'-UTR) or 'weaker' (more structure in the 5'-UTR) with respect to translational efficiency. The insertion of G+C-rich repeats into the 5'-UTR doubled the predicted amount of secondary structure and was sufficient to reduce translational efficiency of the reporter mRNA by 48+/-13%. Translational efficiency of the weaker reporter mRNA was not significantly improved by overexpression of wild-type eIF4E when compared with the stronger reporter mRNA. In contrast, overexpression of the eIF4E kinase Mnk1 [MAP (mitogen-activated protein) kinase signal-integrating kinase 1] was sufficient to increase the translational efficiency of either reporter mRNA, independent of the amount of secondary structure in their respective 5'-UTRs. The increases in translational efficiency produced by Mnk1 occurred in association with corresponding decreases in mRNA levels. These findings indicate that the positive effect of eIF4E phosphorylation on translational efficiency in adult cardiocytes is coupled with the stability of mRNA.


Subject(s)
5' Untranslated Regions/chemistry , Eukaryotic Initiation Factor-4E/metabolism , Myocytes, Cardiac/metabolism , Protein Biosynthesis , Adenoviridae/genetics , Animals , Cats , Cells, Cultured , Genes, Reporter , Genetic Vectors , Nucleic Acid Conformation , Phosphorylation
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