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Background: Genetic factors and microbial imbalances play crucial roles in colorectal cancers (CRCs), yet the impact of infections on cancer initiation remains poorly understood. While bioinformatic approaches offer valuable insights, the rising incidence of CRCs creates a pressing need to precisely identify early CRC events. We constructed a network model to identify continuum states during CRC initiation spanning normal colonic tissue to pre-cancer lesions (adenomatous polyps) and examined the influence of microbes and host genetics. Methods: A Boolean network was built using a publicly available transcriptomic dataset from healthy and adenoma affected patients to identify an invariant Microbe-Associated Colorectal Cancer Signature (MACS). We focused on Fusobacterium nucleatum ( Fn ), a CRC-associated microbe, as a model bacterium. MACS-associated genes and proteins were validated by RT-qPCR, RNA seq, ELISA, IF and IHCs in tissues and colon-derived organoids from genetically predisposed mice ( CPC-APC Min+/- ) and patients (FAP, Lynch Syndrome, PJS, and JPS). Results: The MACS that is upregulated in adenomas consists of four core genes/proteins: CLDN2/Claudin-2 (leakiness), LGR5/leucine-rich repeat-containing receptor (stemness), CEMIP/cell migration-inducing and hyaluronan-binding protein (epithelial-mesenchymal transition) and IL8/Interleukin-8 (inflammation). MACS was induced upon Fn infection, but not in response to infection with other enteric bacteria or probiotics. MACS induction upon Fn infection was higher in CPC-APC Min+/- organoids compared to WT controls. The degree of MACS expression in the patient-derived organoids (PDOs) generally corresponded with the known lifetime risk of CRCs. Conclusions: Computational prediction followed by validation in the organoid-based disease model identified the early events in CRC initiation. MACS reveals that the CRC-associated microbes induce a greater risk in the genetically predisposed hosts, suggesting its potential use for risk prediction and targeted cancer prevention.
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Artificial intelligence (AI) has been an important topic within radiology. Currently, AI is used clinically to assist with the detection of lesions through detection systems. However, a number of recent studies have demonstrated the increased value of neural networks in radiology. With an increasing number of screening requirements for cancers, this review aims to study the accuracy of the numerous AI models used in the detection and diagnosis of breast, lung, and prostate cancers. This study summarizes pertinent findings from reviewed articles and provides analysis on the relevancy to clinical radiology. This study found that whereas AI is showing continual improvement in radiology, AI alone does not surpass the effectiveness of a radiologist. Additionally, it was found that there are multiple variations on how AI should be integrated with a radiologist's workflow.
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BACKGROUND: Standards for reporting surgical adverse events (AEs) vary widely within the scientific literature. Failure to adequately capture AEs hinders efforts to measure the safety of healthcare delivery and improve the quality of care. The aim of the present study is to assess the prevalence and typology of perioperative AE reporting guidelines among surgery and anesthesiology journals. MATERIALS AND METHODS: In November 2021, three independent reviewers queried journal lists from the SCImago Journal & Country Rank (SJR) portal (www.scimagojr.com), a bibliometric indicator database for surgery and anesthesiology academic journals. Journal characteristics were summarized using SCImago, a bibliometric indicator database extracted from Scopus journal data. Quartile 1 (Q1) was considered the top quartile and Q4 bottom quartile based on the journal impact factor. Journal author guidelines were collected to determine whether AE reporting recommendations were included and, if so, the preferred reporting procedures. RESULTS: Of 1409 journals queried, 655 (46.5%) recommended surgical AE reporting. Journals most likely to recommend AE reporting were: by category surgery (59.1%), urology (53.3%), and anesthesia (52.3%); in top SJR quartiles (i.e. more influential); by region, based in Western Europe (49.8%), North America (49.3%), and the Middle East (48.3%). CONCLUSIONS: Surgery and anesthesiology journals do not consistently require or provide recommendations on perioperative AE reporting. Journal guidelines regarding AE reporting should be standardized and are needed to improve the quality of surgical AE reporting with the ultimate goal of improving patient morbidity and mortality.
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Anestesiologia , Humanos , Bibliometria , Fator de Impacto de Revistas , Europa (Continente) , Oriente MédioRESUMO
Magnetic resonance fingerprinting (MRF) is a method to extract quantitative tissue properties such as [Formula: see text] and [Formula: see text] relaxation rates from arbitrary pulse sequences using conventional MRI hardware. MRF pulse sequences have thousands of tunable parameters, which can be chosen to maximize precision and minimize scan time. Here, we perform de novo automated design of MRF pulse sequences by applying physics-inspired optimization heuristics. Our experimental data suggest that systematic errors dominate over random errors in MRF scans under clinically relevant conditions of high undersampling. Thus, in contrast to prior optimization efforts, which focused on statistical error models, we use a cost function based on explicit first-principles simulation of systematic errors arising from Fourier undersampling and phase variation. The resulting pulse sequences display features qualitatively different from previously used MRF pulse sequences and achieve fourfold shorter scan time than prior human-designed sequences of equivalent precision in [Formula: see text] and [Formula: see text] Furthermore, the optimization algorithm has discovered the existence of MRF pulse sequences with intrinsic robustness against shading artifacts due to phase variation.
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Imageamento por Ressonância Magnética/métodos , Algoritmos , Automação , Encéfalo/diagnóstico por imagem , Simulação por Computador , Epilepsia/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias/diagnóstico por imagem , Imagens de FantasmasRESUMO
The goal of this study was to evaluate the accuracy, reproducibility, and efficiency of a 31 P magnetic resonance spectroscopic fingerprinting (31 P-MRSF) method for fast quantification of the forward rate constant of creatine kinase (CK) in mouse hindlimb. The 31 P-MRSF method acquired spectroscopic fingerprints using interleaved acquisition of phosphocreatine (PCr) and γATP with ramped flip angles and a saturation scheme sensitive to chemical exchange between PCr and γATP. Parameter estimation was performed by matching the acquired fingerprints to a dictionary of simulated fingerprints generated from the Bloch-McConnell model. The accuracy of 31 P-MRSF measurements was compared with the magnetization transfer (MT-MRS) method in mouse hindlimb at 9.4 T (n = 8). The reproducibility of 31 P-MRSF was also assessed by repeated measurements. Estimation of the CK rate constant using 31 P-MRSF (0.39 ± 0.03 s-1 ) showed a strong agreement with that using MT-MRS measurements (0.40 ± 0.05 s-1 ). Variations less than 10% were achieved with 2 min acquisition of 31 P-MRSF data. Application of the 31 P-MRSF method to mice subjected to an electrical stimulation protocol detected an increase in CK rate constant in response to stimulation-induced muscle contraction. These results demonstrated the potential of the 31 P-MRSF framework for rapid, accurate, and reproducible quantification of the chemical exchange rate of CK in vivo.
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Creatina Quinase Forma MM/metabolismo , Membro Posterior/diagnóstico por imagem , Proteínas Musculares/metabolismo , Ressonância Magnética Nuclear Biomolecular/métodos , Trifosfato de Adenosina/metabolismo , Animais , Membro Posterior/enzimologia , Concentração de Íons de Hidrogênio , Cinética , Masculino , Camundongos Endogâmicos C57BL , Fósforo , Reprodutibilidade dos TestesRESUMO
Constitutional (Biallelic) Mismatch Repair Deficiency is a rare autosomal recessive disorder characterized by numerous cancers presenting as early as the first decade of life. Biallelic germline variants in one of four mismatch repair genes (MLH1, MSH2, MSH6, or PMS2) cause this devastating disease. Given the rarity of the syndrome, often-asymptomatic tumors, and overlap with neurofibromatosis-1, diagnosis is frequently unrecognized or delayed. We present a unique case of a 14-year-old female with minimal gastrointestinal symptoms diagnosed with invasive adenocarcinoma secondary to biallelic PMS2 variants.
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Colorectal cancer is a rare disease in the pediatric age group and, when present, suggests an underlying genetic predisposition. The most common hereditary colon cancer susceptibility condition, Lynch syndrome (LS), previously known as hereditary nonpolyposis colorectal cancer, is an autosomal dominant condition caused by a germline mutation in 1 of 4 DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6, or PMS2. The mutation-prone phenotype of this disorder is associated with gastrointestinal, endometrial, and other cancers and is now being identified in both symptomatic adolescents with malignancy as well in asymptomatic mutation carriers who are at risk for a spectrum of gastrointestinal and other cancers later in life. We review the DNA MMR system, our present understanding of LS in the pediatric population, and discuss the newly identified biallelic form of the disease known as constitutional mismatch repair deficiency syndrome. Both family history and tumor characteristics can help to identify patients who should undergo genetic testing for these cancer predisposition syndromes. Patients who carry either single allele (LS) or double allele (constitutional mismatch repair deficiency syndrome) mutations in the MMR genes benefit from cancer surveillance programs that target both the digestive and extraintestinal cancer risk of these diseases. Because spontaneous mutation in any one of the MMR genes is extremely rare, genetic counseling and testing are suggested for all at-risk family members.
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Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/genética , Pediatria , Alelos , Neoplasias Colorretais/genética , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Mutação em Linhagem Germinativa , HumanosRESUMO
Typical photoluminescent semiconductor nanoparticles, called quantum dots (QDs), have potential applications in biological labeling. When used to label stem cells, QDs may impair the differentiation capacity of the stem cells. In this study, we synthesized zinc oxide (ZnO) QDs in methanol with an average size of â¼2 nm. We then employed two different types of polyethylene glycol (PEG) molecules (SH-PEG-NH2 and NH2-PEG-NH2) to conjugate ZnO QDs and made them water-dispersible. Fourier transform infrared spectroscopy spectra indicated the attachment of PEG molecules on ZnO QDs. No obvious size alteration was observed for ZnO QDs after PEG conjugation. The water-dispersible ZnO QDs still retained the antibacterial activity and fluorescence intensity. The cytotoxicity evaluation revealed that ZnO QDs at higher concentrations decreased cell viability but were generally safe at 30 ppm or below. Cell lines of hepatocytes (HepG2), osteoblasts (MC3T3-E1) and mesenchymal stem cells (MSCs) were successfully labeled by the water-dispersible ZnO QDs at 30 ppm. The ZnO QD-labeled MSCs maintained their stemness and differentiation capacity. Therefore, we conclude that the water-dispersible ZnO QDs developed in this study have antibacterial activity, low cytotoxicity, and proper labeling efficiency, and can be used to label a variety of cells including stem cells.
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Antibacterianos/síntese química , Antibacterianos/farmacologia , Pontos Quânticos/toxicidade , Coloração e Rotulagem , Água/química , Óxido de Zinco/síntese química , Tecido Adiposo/citologia , Células-Tronco Adultas/citologia , Células-Tronco Adultas/efeitos dos fármacos , Animais , Antibacterianos/química , Morte Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Resinas Epóxi/síntese química , Resinas Epóxi/química , Escherichia coli/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Hidrodinâmica , Camundongos , Testes de Sensibilidade Microbiana , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Anidridos Ftálicos/síntese química , Anidridos Ftálicos/química , Pontos Quânticos/química , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Eletricidade Estática , Óxido de Zinco/químicaRESUMO
PURPOSE: The present study was designed to address whether osteoblasts play a synergistic role in promoting mesenchymal stem cell (MSC) osteogenesis in a direct cell-cell contact co-culture model. METHODS: Murine C3H10T1/2 and MC3T3-E1 cell lines were mixed and plated onto 12-well culture plates and co-cultured at various ratios of initial cell densities. To compare the possible improvement on osteogenic differentiation, co-culture cells were served with or without osteogenic supplements in culture medium. RESULTS: Weak osteogenesis was induced in MSCs co-cultured in an untreated medium with different ratios of osteoblasts. An osteoblast-dependent increase in osteogenic gene expression of Runx2, type I collagen, and osteocalcin was observed over time. Moreover, both alkaline phosphatase (ALP) activity and calcium deposition were distinctly enhanced at levels that were proportional to the quantity of osteoblasts in the culture. The increases in mRNA expression and ALP activity were greater in co-cultures treated with osteogenic supplements than in untreated cultures. However, the production of ALP activity followed by a distinct matrix mineralization was lower in osteogenic-treated cultures containing greater numbers of osteoblasts. This suggests that a higher density of osteoblasts may lead to weak osteogenesis of MSCs by direct cell-cell contact co-culture in an untreated environment. Furthermore, additional osteogenic supplements may act synergistically with osteoblasts to accelerate matrix mineralization by reducing the process of osteogenic differentiation in osteogenic treated co-cultures. CONCLUSIONS: The present work may improve the understanding of MSC osteogenesis and may provide benefits for regenerative medicine.
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Comunicação Celular/fisiologia , Diferenciação Celular/fisiologia , Células-Tronco Mesenquimais/citologia , Osteoblastos/citologia , Osteogênese/fisiologia , Células 3T3 , Fosfatase Alcalina/metabolismo , Animais , Cálcio/metabolismo , Técnicas de Cocultura , Expressão Gênica , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Osteoblastos/metabolismoRESUMO
BACKGROUND: Patients with hamartomatous polyposis syndromes have increased risk for colorectal cancer (CRC). Although progression of polyps to carcinoma is observed, pathogenic mechanisms remain unknown. The authors examined whether familial hamartomatous polyps harbor defects in DNA mismatch repair (MMR), and assayed for somatic mutation of PTEN, a gene inactivated in the germline of some hamartomatous polyposis syndrome patients. METHODS: Ten hamartomatous polyposis syndrome patients were genotyped for germline mutations. Epithelial and nonepithelial polyp DNA were assayed for microsatellite instability (MSI) and PTEN frameshift mutation. DNA MMR and PTEN protein expression were assessed in all polyps by immunohistochemistry. In addition, 99 MSI-high sporadic CRCs and 50 each of hMLH1(-/-) and hMSH3(-/-) cell clones were examined for PTEN frameshifts. RESULTS: Twenty-five (58%) of 43 hamartomatous polyposis syndrome polyps demonstrated dinucleotide or greater MSI in polyp epithelium, consistent with hMSH3 deficiency. MSI domains lost hMSH3 expression, and PTEN expression was lost in polyps from germline PTEN patients; sporadic hamartomatous polyps did not show any of these findings. PTEN analysis revealed wild type exon 7 and 8 sequences suggestive of nonexistent or rare events for PTEN frameshifts; however, MSI-high sporadic CRC showed 11 (11%) of 99 frameshifts within PTEN, with 4 tumors having complete loss of PTEN expression. Subcloning hMLH1(-/-) and hMSH3(-/-) cells revealed somatic PTEN frameshifts in 4% and 12% of clones, respectively. CONCLUSIONS: Nondysplastic epithelium from hamartomatous polyposis syndrome polyps harbors hMSH3 defects, which may prime neoplastic transformation. Polyps from PTEN(+/-) patients lose PTEN expression, but loss is not a universal early feature of all hamartomatous polyposis syndrome. However, PTEN frameshifts can occur in hMSH3-deficient cells, suggesting that hMSH3 deficiency could drive hamartomatous polyposis syndrome tumorigenesis.
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Proteínas de Ligação a DNA/genética , PTEN Fosfo-Hidrolase/genética , Síndrome de Peutz-Jeghers/genética , Adolescente , Adulto , Linhagem Celular Tumoral , Criança , Pré-Escolar , Neoplasias Colorretais/genética , Deleção de Genes , Instabilidade Genômica , Humanos , Proteína 3 Homóloga a MutSRESUMO
Familial adenomatous polyposis [FAP (OMIM 175100)] is an autosomal dominant colorectal cancer predisposition syndrome characterized by hundreds to thousands of colonic polyps and, if untreated by a combination of screening and/or surgical intervention, an approximately 99% lifetime risk of colorectal cancer. A subset of FAP patients develop an attenuated form of the condition characterized by lower numbers of colonic polyps (highly variable, but generally less than 100) and a lower lifetime risk of colorectal cancer, on the order of 70%. We report the diagnosis of three attenuated FAP families due to a 1.4-kb deletion within intron 14 of APC, originally reported clinically as a variant of unknown significance (VUS). Sequence analysis suggests that this arose through an Alu-mediated recombination event with a locus on chromosome 6q22.1. This mutation is inherited by family members who presented with an attenuated FAP phenotype, with variable age of onset and severity. Sequence analysis of mRNA revealed an increase in the level of aberrant splicing of exon 14, resulting in the generation of an exon 13-exon 15 splice-form that is predicted to lead to a frameshift and protein truncation at codon 673. The relatively mild phenotypic presentation and the intra-familial variation are consistent with the leaky nature of exon 14 splicing in normal APC. The inferred founder of these three families may account for as yet undetected affected branches of this kindred. This and similar types of intronic mutations may account for a significant proportion of FAP cases where APC clinical analysis fails because of the current limitations of testing options.
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Polipose Adenomatosa do Colo/diagnóstico , Polipose Adenomatosa do Colo/genética , Processamento Alternativo/genética , Genes APC , Íntrons/genética , Polimorfismo Genético , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Feminino , Deleção de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Linhagem , Polimorfismo Genético/fisiologia , Sítios de Splice de RNA/genética , Adulto JovemRESUMO
Colon polyps are a common finding in pediatrics and can present with rectal bleeding, abdominal pain, or polyp prolapse from the rectum. Histologically classified as hamartomas, these isolated pediatric polyps lack epithelial dysplasia and have no cancer risk. However, when polyps are present in greater numbers, or are associated with a family history of polyps or colon or other cancers, a polyposis or hereditary colorectal cancer syndrome should be considered. Using a case-based format, this article reviews the clinical features and provides updates on the three most common hamartomatous polyp syndromes of childhood: juvenile polyposis syndrome, Peutz-Jeghers syndrome, and the PTEN hamartoma tumor syndrome. Each syndrome has distinctive intestinal and extra-intestinal findings that, when present, can guide genetic counseling and testing. Lifelong cancer surveillance is crucial to disease prevention and the long-term health of these patients and their families.
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Polipose Adenomatosa do Colo/diagnóstico , Predisposição Genética para Doença , Hamartoma/diagnóstico , Síndrome de Peutz-Jeghers/diagnóstico , Quinases Proteína-Quinases Ativadas por AMP , Polipose Adenomatosa do Colo/genética , Adolescente , Biópsia , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Criança , Pré-Escolar , Colonoscopia/métodos , DNA de Neoplasias/genética , Diagnóstico Diferencial , Feminino , Hamartoma/genética , Humanos , Masculino , Mutação , PTEN Fosfo-Hidrolase/genética , Síndrome de Peutz-Jeghers/genética , Proteínas Serina-Treonina Quinases/genética , Proteína Smad4/genéticaRESUMO
Synthesis of ultrasmall water-soluble fluorescent gold nanoclusters is reported. The clusters have a decent quantum yield, high colloidal stability, and can be readily conjugated with biological molecules. Specific staining of cells and nonspecific uptake by living cells is demonstrated.
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Corantes Fluorescentes/síntese química , Ouro/química , Nanopartículas Metálicas/química , Coloração e Rotulagem/métodos , Animais , Bovinos , Linhagem Celular Tumoral , Sobrevivência Celular , Cromatografia em Gel , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Humanos , Polietilenoglicóis/química , Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Espectrofotometria Ultravioleta , Especificidade por SubstratoRESUMO
Microsatellite instability promotes colonic tumorigenesis through generating frameshift mutations at coding microsatellites of tumor suppressor genes, such as TGFBR2 and ACVR2. As a consequence, signaling through these TGFbeta family receptors is abrogated in DNA Mismatch repair (MMR)-deficient tumors. How these mutations occur in real time and mutational rates of these human coding sequences have not previously been studied. We utilized cell lines with different MMR deficiencies (hMLH1-/-, hMSH6-/-, hMSH3-/-, and MMR-proficient) to determine mutation rates. Plasmids were constructed in which exon 3 of TGFBR2 and exon 10 of ACVR2 were cloned +1 bp out of frame, immediately after the translation initiation codon of an enhanced GFP (EGFP) gene, allowing a -1 bp frameshift mutation to drive EGFP expression. Mutation-resistant plasmids were constructed by interrupting the coding microsatellite sequences, preventing frameshift mutation. Stable cell lines were established containing portions of TGFBR2 and ACVR2, and nonfluorescent cells were sorted, cultured for 7-35 days, and harvested for flow cytometric mutation detection and DNA sequencing at specific time points. DNA sequencing revealed a -1 bp frameshift mutation (A9 in TGFBR2 and A7 in ACVR2) in the fluorescent cells. Two distinct fluorescent populations, M1 (dim, representing heteroduplexes) and M2 (bright, representing full mutants) were identified, with the M2 fraction accumulating over time. hMLH1 deficiency revealed 11 (5.91 x 10(-4)) and 15 (2.18 x 10(-4)) times higher mutation rates for the TGFBR2 and ACVR2 microsatellites compared to hMSH6 deficiency, respectively. The mutation rate of the TGFBR2 microsatellite was approximately 3 times higher in both hMLH1 and hMSH6 deficiencies than the ACVR2 microsatellite. The -1 bp frameshift mutation rates of TGFBR2 and ACVR2 microsatellite sequences are dependent upon the human MMR background.
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Receptores de Activinas Tipo II/genética , Reparo de Erro de Pareamento de DNA/genética , Mutação da Fase de Leitura , Repetições de Microssatélites/genética , Proteínas Serina-Treonina Quinases/genética , Receptores de Fatores de Crescimento Transformadores beta/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Linhagem Celular , Proteínas de Ligação a DNA/genética , Éxons , Proteínas de Fluorescência Verde/genética , Humanos , Proteína 1 Homóloga a MutL , Proteína 3 Homóloga a MutS , Mutagênese Sítio-Dirigida , Proteínas Nucleares/genética , Receptor do Fator de Crescimento Transformador beta Tipo IIRESUMO
OBJECTIVES: Cyclooxygenase-2 (COX-2) expression is increased in colorectal cancers and has been reported to be upregulated in Peutz-Jeghers polyps. To determine whether germline and somatic loss of BMPR1A in polyps from a patient with juvenile polyposis syndrome have altered COX-2 expression, we characterized a patient with juvenile polyposis syndrome for BMPR1A germline mutations and examined the polyps for BMPR1A expression and COX-2 expression. PATIENTS AND METHODS: DNA analysis for BMPR1A was performed on a patient with juvenile polyposis syndrome. Multiple polypectomies were performed, and several polyps showed adenomatous change. Genomic DNA was extracted from polyp material for loss of heterozygosity (LOH) analyses with microsatellite markers. Immunohistochemistry was performed on sections using antibodies for BMPR1A and COX-2. RESULTS: The kindred possessed a germline BMPR1A missense mutation. In polyp domains containing cystic and adenomatous epithelium, no LOH was observed using markers near the BMPR1A locus. Immunostaining indicated decreased expression of phospho-SMAD1 (pSMAD1), functionally downstream of the mutant BMPR1A receptor in the cystic epithelium, with further reduction in adenomatous portions within the polyp. COX-2 protein, normally not expressed in the colon, was present and increased in polyp epithelium. CONCLUSIONS: Decreased expression of pSMAD1 in the cystic epithelium with further reduction in the adenomatous area, and increase in COX-2 expression within polyps from the BMPR1A heterozygote, suggest a potential mechanism for adenomatous pathogenesis in these hamartomatous polyps. This may imply that COX-2 inhibitors could be a means for chemoprevention in this syndrome.
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Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Pólipos do Colo/metabolismo , Ciclo-Oxigenase 2/biossíntese , Síndrome de Peutz-Jeghers/genética , Adulto , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/biossíntese , Neoplasias do Colo/etiologia , Pólipos do Colo/complicações , Mutação em Linhagem Germinativa , Humanos , Masculino , Mutação de Sentido Incorreto , Linhagem , Proteína Smad1/biossínteseRESUMO
Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta superfamily, which utilize BMP receptors and intracellular SMADs to transduce their signals to regulate cell differentiation, proliferation, and apoptosis. Because mutations in BMP receptor type IA (BMPRIA) and SMAD4 are found in the germline of patients with the colon cancer predisposition syndrome juvenile polyposis, and because the contribution of BMP in colon cancers is largely unknown, we examined colon cancer cells and tissues for evidence of BMP signaling and determined its growth effects. We determined the presence and functionality of BMPR1A by examining BMP-induced phosphorylation and nuclear translocation of SMAD1; transcriptional activity via a BMP-specific luciferase reporter; and growth characteristics by cell cycle analysis, cell growth, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolic assays. These assays were also performed after transfection with a dominant negative (DN) BMPR1A construct. In SMAD4-null SW480 cells, we examined BMP effects on cellular wound assays as well as BMP-induced transcription in the presence of transfected SMAD4. We also determined the expression of BMPR1A, BMP ligands, and phospho-SMAD1 in primary human colon cancer specimens. We found intact BMP signaling and modest growth suppression in HCT116 and two derivative cell lines and, surprisingly, growth suppression in SMAD4-null SW480 cells. BMP-induced SMAD signaling and BMPR1A-mediated growth suppression were reversed with DN BMPR1A transfection. BMP2 slowed wound closure, and transfection of SMAD4 into SW480 cells did not change BMP-specific transcriptional activity over controls due to receptor stimulation by endogenously produced ligand. We found no cell cycle alterations with BMP treatment in the HCT116 and derivative cell lines, but there was an increased G1 fraction in SW480 cells that was not due to increased p21 transcription. In human colon cancer specimens, BMP2 and BMP7 ligands, BMPRIA, and phospho-SMAD1 were expressed. In conclusion, BMP signaling is intact and growth suppressive in human colon cancer cells. In addition to SMADs, BMP may utilize SMAD4-independent pathways for growth suppression in colon cancers.
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Proteínas Morfogenéticas Ósseas/metabolismo , Neoplasias do Colo/patologia , Neoplasias do Colo/fisiopatologia , Transdução de Sinais , Linhagem Celular Tumoral , Proliferação de Células , HumanosRESUMO
Electromagnetic stimulation has been documented to treat recalcitrant problems of musculoskeletal system. Yet, the underlying mechanisms are not completely understood. In this study, we investigated effect of pulsed electromagnetic fields (PEMF) with parameters modified from clinical bone growth stimulator on osteoclast formation, bone resorption, and cytokines associated with osteoclastogenesis. Marrow cells were harvested from both femora and tibiae of 6 week-old mice and cultured in 8-well chamber slides or 16-well calcium phosphate apatite-coated multitest slides. After 1-day incubation, marrow cells were exposed to PEMF at different electric field intensities for 2h/day and continued for 9 days. Osteoprotegerin (OPG), receptor activator of NFkappaB-ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) concentrations of each group were determined after PEMF stimulation. Osteoclast identity was confirmed by both tartrate resistant acid phosphatase (TRAP) stain and bone resorption assay. A statistically significant increase and decrease of osteoclastogenesis and bone resorption areas were found when exposed to PEMF with different intensities. Besides, consistent correlations among OPG, RANKL, M-CSF, osteoclast numbers, and bone resorption after exposure to different intensities of PEMF were observed. These data demonstrated that PEMF with different intensities could regulate osteoclastogenesis, bone resorption, OPG, RANKL, and M-CSF concentrations in marrow culture system.