RESUMEN
Mononuclear Fe ions ligated by nitrogen (FeNx) dispersed on nitrogen-doped carbon (Fe-N-C) serve as active centers for electrocatalytic O2 reduction and thermocatalytic aerobic oxidations. Despite their promise as replacements for precious metals in a variety of practical applications, such as fuel cells, the discovery of new Fe-N-C catalysts has relied primarily on empirical approaches. In this context, the development of quantitative structure-reactivity relationships and benchmarking of catalysts prepared by different synthetic routes and by different laboratories would be facilitated by the broader adoption of methods to quantify atomically dispersed FeNx active centers. In this study, we develop a kinetic probe reaction method that uses the aerobic oxidation of a model hydroquinone substrate to quantify the density of FeNx centers in Fe-N-C catalysts. The kinetic method is compared with low-temperature Mössbauer spectroscopy, CO pulse chemisorption, and electrochemical reductive stripping of NO derived from NO2- on a suite of Fe-N-C catalysts prepared by diverse routes and featuring either the exclusive presence of Fe as FeNx sites or the coexistence of aggregated Fe species in addition to FeNx. The FeNx site densities derived from the kinetic method correlate well with those obtained from CO pulse chemisorption and Mössbauer spectroscopy. The broad survey of Fe-N-C materials also reveals the presence of outliers and challenges associated with each site quantification approach. The kinetic method developed here does not require pretreatments that may alter active-site distributions or specialized equipment beyond reaction vessels and standard analytical instrumentation.
RESUMEN
OBJECTIVE: The aim of the study was to evaluate the ability of a combinatorial pharmacogenomic test to predict medication blood levels and relative clinical improvements in a selected pediatric population. METHODS: This study enrolled patients between ages 3 to 18 years who presented to a pediatric emergency department with acute psychiatric, behavioral, or mental health crisis and/or concerns, and had previously been prescribed psychotropic medications. Patients received combinatorial pharmacogenomic testing with medications categorized according to gene-drug interactions (GDIs); medications with a GDI were considered "incongruent," and medications without a GDI were considered "congruent." Blood levels for escitalopram, fluoxetine, aripiprazole, and clonidine were evaluated according to level of GDI. Relative clinical improvements in response to the prescribed psychotropic medications were measured using a parent-rated Clinical Global Impression of Improvement (CGI-I) assessment, where lower scores corresponded with greater improvement. RESULTS: Of the 100 patients enrolled, 73% reported taking ≥1 incongruent medication. There was no significant difference in CGI-I scores between patients prescribed congruent versus incongruent medications (3.37 vs 3.68, P = 0.343). Among patients who presented for depression or suicidal ideation, those prescribed congruent medications had significantly lower CGI-I scores compared with those taking incongruent medications ( P = 0.036 for depression, P = 0.018 for suicidal ideation). There was a significant association between medication GDI and blood levels for aripiprazole (n = 15, P = 0.01) and escitalopram (n = 10, P = 0.01). CONCLUSIONS: Our preliminary findings suggest that combinatorial pharmacogenomic testing can predict medication blood levels and relative outcomes based on medication congruency in children presenting to an emergency department with acute psychiatric/behavioral crises. Additional studies will be needed to confirm these findings.
Asunto(s)
Escitalopram , Farmacogenética , Humanos , Niño , Preescolar , Adolescente , Aripiprazol/uso terapéutico , Psicotrópicos/uso terapéutico , Servicio de Urgencia en HospitalRESUMEN
We report a strategy to integrate atomically dispersed iron within a heterogeneous nitrogen-doped carbon (N-C) support, inspired by routes for metalation of molecular macrocyclic iron complexes. The N-C support, derived from pyrolysis of a ZIF-8 metal-organic framework, is metalated via solution-phase reaction with FeCl2 and tributyl amine, as a Brønsted base, at 150 °C. Fe active sites are characterized by 57Fe Mössbauer spectroscopy and aberration-corrected scanning transmission electron microscopy. The site density can be increased by selective removal of Zn2+ ions from the N-C support prior to metalation, resembling the transmetalation strategy commonly employed for the preparation of molecular Fe-macrocycles. The utility of this approach is validated by the higher catalytic rates (per total Fe) of these materials relative to established Fe-N-C catalysts, benchmarked using an aerobic oxidation reaction.
Asunto(s)
Carbono , Nitrógeno , Nitrógeno/química , Carbono/química , Hierro/química , AminasRESUMEN
The COVID-19 pandemic was stressful for everyone, particularly for families who had to supervise and support children, facilitate remote schooling, and manage work and home life. We consider how families coped with pandemic-related stress using the video game Animal Crossing: New Horizons. Combining a family coping framework with theorizing about media as a coping tool, this interview study of 27 families (33 parents and 37 children) found that parents and children individual coped with pandemic-related stress with media. Parents engaged in protective buffering of their children with media, taking on individual responsibility to cope with a collective problem. Families engaged in communal coping, whereby media helped the family cope with a collective problem, taking on shared ownership and responsibility. We provide evidence for video games as coping tools, but with the novel consideration of family coping with media.
RESUMEN
This review covers all aspects of 9-borafluorene chemistry, from the first attempted synthesis in 1960 to the present. This class of molecules consists of a tricyclic system featuring a central antiaromatic BC4 ring with two fused arene groups. The synthetic routes to all 9-borafluorenes and their adducts are presented. The Lewis acidity and photophysical properties outlined demonstrate potential utility as sensors and in electronic materials. The reactivity of borafluorenes reveals their prospects as reagents for the synthesis of other boron-containing molecules. The appealing traits of 9-borafluorenes have stimulated investigations into analogues that bear different aromatic groups fused to the central BC4 ring. Finally, we offer our views on the challenges and future of borafluorene chemistry.
RESUMEN
Vaccine and antiviral development against SARS-CoV-2 infection or COVID-19 disease would benefit from validated small animal models. Here, we show that transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) by the human cytokeratin 18 promoter (K18 hACE2) represent a susceptible rodent model. K18 hACE2 transgenic mice succumbed to SARS-CoV-2 infection by day 6, with virus detected in lung airway epithelium and brain. K18 ACE2 transgenic mice produced a modest TH1/2/17 cytokine storm in the lung and spleen that peaked by day 2, and an extended chemokine storm that was detected in both lungs and brain. This chemokine storm was also detected in the brain at day 6. K18 hACE2 transgenic mice are, therefore, highly susceptible to SARS-CoV-2 infection and represent a suitable animal model for the study of viral pathogenesis, and for identification and characterization of vaccines (prophylactic) and antivirals (therapeutics) for SARS-CoV-2 infection and associated severe COVID-19 disease.
Asunto(s)
Enzima Convertidora de Angiotensina 2 , COVID-19 , Modelos Animales de Enfermedad , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/inmunología , Animales , Encéfalo/inmunología , Encéfalo/patología , Encéfalo/virología , COVID-19/inmunología , COVID-19/patología , Síndrome de Liberación de Citoquinas/inmunología , Síndrome de Liberación de Citoquinas/patología , Susceptibilidad a Enfermedades , Predisposición Genética a la Enfermedad , Queratina-18/genética , Pulmón/inmunología , Pulmón/patología , Pulmón/virología , Ratones , Ratones Transgénicos , Mortalidad , Regiones Promotoras Genéticas/genética , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/patología , Mucosa Respiratoria/virología , Virosis/inmunología , Virosis/patologíaRESUMEN
OBJECTIVES: From 2011 to 2015, psychiatric emergency department visits among youth in the United States increased 28% and psychiatric visits made up 10% of all pediatric emergency department (ED) visits. Previous research has focused on adolescent mental health, with little characterization of children 10 years of age and younger with mental health complaints. The primary objective of this study was to describe these children who presented to a pediatric ED for mental health complaints in terms of demographics and psychosocial factors. METHODS: One researcher reviewed medical records of children 10 years and younger who presented to the Children's of Alabama ED between January 1, 2016 and May 31, 2016 with a mental health-related chief complaint. Patient data were then categorized based on demographic information, characteristics of the ED visit, and medical and social history. Descriptive analyses were run using SAS version 9.4. RESULTS: In total, 222 patients 10 years and younger were seen between January 1 and May 31, 2016. This age group makes up 20% of all of the children seen in the ED for mental health-related complaints. Patients were 73% male (n = 162) and ages 3 to 10 years, with a mean age of 7.8 years. Patients were 55% white (n = 122), 42% African American (n = 94), 1% Hispanic (n = 2), and 1% other ethnicity (n = 3). Patients' insurance coverage was 76% Medicaid (n = 168), 18% private insurance (n = 39), and 6% uninsured (n = 14). Of the 219 patients treated in the ED (3 left without treatment), 45% of patients were admitted (n = 100). Univariate analyses showed increased odds of admission for children with 3 or more prior psychiatric diagnoses (odds ratio [OR] 2.33, P = 0.03), a family history of psychiatric illness (OR 2.53, P < 0.01), history of any previous psychiatric care (OR 2.61, P = 0.01), a history of trauma (OR 1.84, P = 0.03), and a chief complaint of suicidal ideation (OR 1.54, P < 0.01). Analyses showed a decreased odds of admission for children referred to the ED by their school (OR -1.12, P < 0.01). CONCLUSIONS: The pediatric ED sees a significant number of children ages 10 years and younger for mental health-related complaints. Nearly half of these children were admitted for psychiatric care. Several factors were found to predict admission, which reflect psychosocial influences. These psychosocial factors are important targets for intervention both in the ED and in the community.
Asunto(s)
Servicio de Urgencia en Hospital/estadística & datos numéricos , Trastornos Mentales/diagnóstico , Alabama/epidemiología , Niño , Preescolar , Servicio de Urgencia en Hospital/organización & administración , Femenino , Humanos , Cobertura del Seguro/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Masculino , Trastornos Mentales/epidemiología , Trastornos Mentales/psicología , Estudios RetrospectivosRESUMEN
INTRODUCTION: The baboon is a well-characterized model of human early stage atherosclerosis. However, histological and morphological changes involved in atherogenesis in baboons are not known. Previously, we challenged baboons with a high-cholesterol, high-fat diet for two years and observed fatty streak and plaque lesions in iliac arteries (RCIA). METHODS: We evaluated histological and morphological changes of baboon arterial lesions and control arteries. In addition, we evaluated the vascular expression of CD68 and SMαA markers with progression of atherosclerosis. RESULTS: We observed changes that correlated with extent of atherosclerosis, including increased maximum intimal thickness. We demonstrated at molecular level the infiltration of smooth muscle cells and macrophages into the intimal layer. Further, we observed histological and morphological discordancy between the affected and adjacent areas of the same RCIA. CONCLUSION: Atherogenesis in baboons is accompanied by histological, morphological, and molecular changes, as in humans, providing insights to evaluate the mechanisms underlying early stage atherosclerosis in target tissues.
Asunto(s)
Aterosclerosis/patología , Colesterol/efectos adversos , Dieta Alta en Grasa/efectos adversos , Arteria Ilíaca/patología , Animales , Aterosclerosis/etiología , Papio hamadryasRESUMEN
PURPOSE: Nonalcoholic fatty liver disease (NAFLD) is considered the most common form of silent liver disease in the United States and obesity is associated with increased risk of NAFLD. Obstructive sleep apnea (OSA) which is common in obese individuals is associated with a greater incidence of NAFLD, which in turn, increases the risk for hepatocellular carcinoma (HCC). It is unclear how obesity, OSA and NAFLD interrelate nor how they collectively contribute to an increased risk for developing HCC. PATIENTS AND METHODS: Male BALB/c mice were exposed to diethylnitrosamine and phenobarbital followed by 48 weeks of either standard chow diet (chow), chow with hypoxia, high-fat diet, or a combination of hypoxia and high-fat diet. We noninvasively monitored tumor development using micro-CT imaging. We tracked the total weight gained throughout the study. We evaluated liver histology, fat accumulation, carbonic anhydrase 9 (CA9) and hypoxia-inducible factor 1-alpha (HIF-1α) expression, as well as, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). RESULTS: A high-fat diet without hypoxia led to the development of obesity that induced hepatic steatosis and promoted tumorigenesis. Animals on a high-fat diet and that were also exposed to hypoxia had lower total weight gain, lower steatosis, lower serum AST and ALT levels, and fewer number of hepatic adenomas than a high-fat diet without hypoxia. CONCLUSION: These findings suggest that hypoxia abrogates obesity, hepatic steatosis, and hepatic tumorigenesis related to a high-fat diet.
RESUMEN
Micro-computed tomography (micro-CT) coupled with tissue, or vascular, specific contrast agent has emerged as a powerful tool for detecting and monitoring tumor growth in the liver of murine animals. Intravenous injections of contrast agents can be technically challenging and lead to errors that can considerably influence the outcome of a preclinical study, prompting an alternative method. Here we assessed the effectiveness of intraperitoneal injections of polyiodinated triglycerides emulsions (Fenestra LC) in micro-CT imaging of young SCID (8 weeks) and old BALB/c (48 weeks) mice with xenograft or carcinogen-induced liver tumors, respectively, and determined an optimal acquisition time. Utilizing an intraperitoneal injection is a viable alternative administration route for using Fenestra in detection and quantification of murine liver tumor burden.
Asunto(s)
Medios de Contraste/farmacología , Neoplasias Hepáticas/diagnóstico por imagen , Hígado/diagnóstico por imagen , Microtomografía por Rayos X/métodos , Animales , Humanos , Inyecciones Intraperitoneales , Hígado/efectos de los fármacos , Hígado/patología , Neoplasias Hepáticas/patología , RatonesRESUMEN
BACKGROUND: Live-cell fluorescence microscopy (LCFM) is a powerful tool used to investigate cellular dynamics in real time. However, the capacity to simultaneously measure DNA content in cells being tracked over time remains challenged by dye-associated toxicities. The ability to measure DNA content in single cells by means of LCFM would allow cellular stage and ploidy to be coupled with a variety of imaging directed analyses. Here we describe a widely applicable nontoxic approach for measuring DNA content in live cells by fluorescence microscopy. This method relies on introducing a live-cell membrane-permeant DNA fluorophore, such as Hoechst 33342, into the culture medium of cells at the end of any live-cell imaging experiment and measuring each cell's integrated nuclear fluorescence to quantify DNA content. Importantly, our method overcomes the toxicity and induction of DNA damage typically caused by live-cell dyes through strategic timing of adding the dye to the cultures; allowing unperturbed cells to be imaged for any interval of time before quantifying their DNA content. We assess the performance of our method empirically and discuss adaptations that can be implemented using this technique. RESULTS: Presented in conjunction with cells expressing a histone 2B-GFP fusion protein (H2B-GFP), we demonstrated how this method enabled chromosomal segregation errors to be tracked in cells as they progressed through cellular division that were later identified as either diploid or polyploid. We also describe and provide an automated Matlab-derived algorithm that measures the integrated nuclear fluorescence in each cell and subsequently plots these measurements into a cell cycle histogram for each frame imaged. The algorithm's accurate assessment of DNA content was validated by parallel flow cytometric studies. CONCLUSIONS: This method allows the examination of single-cell dynamics to be correlated with cellular stage and ploidy in a high-throughput fashion. The approach is suitable for any standard epifluorescence microscope equipped with a stable illumination source and either a stage-top incubator or an enclosed live-cell incubation chamber. Collectively, we anticipate that this method will allow high-resolution microscopic analysis of cellular processes involving cell cycle progression, such as checkpoint activation, DNA replication, and cellular division.
RESUMEN
The reactions of 9-borafluorenes with organic azides result in either the insertion of the α-nitrogen and elimination of N2 or the insertion of the γ-nitrogen to generate the corresponding phenanthrene analogues with boron and nitrogen in the 9- and 10-positions, respectively.
RESUMEN
BACKGROUND: The presence of B cells in early stage non-small cell lung cancer (NSCLC) is associated with longer survival, however, the role these cells play in the generation and maintenance of anti-tumor immunity is unclear. B cells differentiate into a variety of subsets with differing characteristics and functions. To date, there is limited information on the specific B cell subsets found within NSCLC. To better understand the composition of the B cell populations found in NSCLC we have begun characterizing B cells in lung tumors and have detected a population of B cells that are CD79A+CD27-IgD-. These CD27-IgD- (double-negative) B cells have previously been characterized as unconventional memory B cells and have been detected in some autoimmune diseases and in the elderly population but have not been detected previously in tumor tissue. METHODS: A total of 15 fresh untreated NSCLC tumors and 15 matched adjacent lung control tissues were dissociated and analyzed by intracellular flow cytometry to detect the B cell-related markers CD79A, CD27 and IgD. All CD79A+ B cells subsets were classified as either naïve (CD27-IgD+), affinity-matured (CD27+IgD-), early memory/germinal center cells (CD27+IgD+) or double-negative B cells (CD27-IgD-). Association of double-negative B cells with clinical data including gender, age, smoking status, tumor diagnosis and pathologic differentiation status were also examined using the logistic regression analysis for age and student's t-test for all other variables. Associations with other B cell subpopulations were examined using Spearman's rank correlation. RESULTS: We observed that double-negative B cells were frequently abundant in lung tumors compared to normal adjacent controls (13 out of 15 cases), and in some cases made up a substantial proportion of the total B cell compartment. The presence of double-negative cells was also found to be inversely related to the presence of affinity-matured B cells within the tumor, Spearman's coefficient of - 0.76. CONCLUSIONS: This study is the first to observe the presence of CD27-IgD- double-negative B cells in human NSCLC and that this population is inversely correlated with traditional affinity-matured B cell populations.
Asunto(s)
Afinidad de Anticuerpos/inmunología , Linfocitos B/patología , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Carcinoma de Pulmón de Células no Pequeñas/patología , Inmunoglobulina D/metabolismo , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/patología , Miembro 7 de la Superfamilia de Receptores de Factores de Necrosis Tumoral/metabolismo , Anciano , Anciano de 80 o más Años , Proliferación Celular , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND AND PURPOSE: This paper describes a student-led co-curricular training program to increase pharmacy student proficiency with medical Spanish terminology. Western University of Health Sciences (WesternU) pharmacy students frequently can interact with Spanish-speaking patients in experiential rotations. Moreover, the clear majority of program graduates remain in California, a state with a high Spanish-speaking population. Developing foundational knowledge of medical Spanish terminology can enhance communication with Spanish-speaking patients, who may have limited English proficiency and experience a lack of language concordance when interacting with the healthcare system. Providing training in medical terminology in another language is important because communication barriers have been associated with adverse medical outcomes, such as poor medication adherence. EDUCATIONAL ACTIVITY AND SETTING: The development of the training logistics and materials are described for replication of the process, whether with medical Spanish or other languages. Students in the pharmacy program developed the medical Spanish training that is now a robust co-curricular activity with over 100 students participating in the training each semester. An important aspect of the WesternU co-curricular activity is that students develop materials, create learning activities, and facilitate training.
Asunto(s)
Curriculum/tendencias , Lenguaje , Relaciones Profesional-Paciente , Estudiantes de Farmacia/psicología , California , Barreras de Comunicación , Educación en Farmacia/métodos , HumanosRESUMEN
Universities are under pressure to increase external research funding, and some federal agencies offer programs to expand research capacity in certain kinds of institutions. However, conflicts within faculty roles and other aspects of university operations influence the effectiveness of particular strategies for increasing research activity. We review conventional approaches to increasing research, focusing on outcomes for individual faculty members and use one federally-funded effort to build cancer-related research capacity at a public university as an example to explore the impact of various strategies on research outcomes. We close with hypotheses that should be tested in future formal studies.
RESUMEN
The receptor tyrosine kinases (RTKs) TYRO3, AXL and MERTK (TAM) have well-described oncogenic functions in a number of cancers. Notwithstanding, TAM RTKs are also potent and indispensable inhibitors of inflammation. The combined deletion of Axl and Mertk in mice enhances chronic inflammation and autoimmunity, including increased inflammation in the gut and colitis-associated cancer. On the other hand, deletion of Tyro3 increases the risk of allergic responses. Therefore, the indiscriminate inhibition of these TAM RTKs could result in undesirable immunological diseases. Here we show that AXL, but not MERTK or TYRO3 expression is enhanced in late stage colorectal cancer (CRC) and AXL expression associates with a cell migration gene signature. Silencing AXL or the inhibition of AXL kinase activity significantly inhibits tumor cell migration and invasion. These results indicate that the selective inhibition of AXL alone might confer sufficient therapeutic benefit in CRC, while preserving at least some of the beneficial, anti-inflammatory effects of MERTK and TYRO3 RTKs.
Asunto(s)
Carcinoma/genética , Movimiento Celular/fisiología , Proliferación Celular/fisiología , Neoplasias Colorrectales/genética , Invasividad Neoplásica/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Tirosina Quinasas Receptoras/genética , Carcinoma/metabolismo , Carcinoma/patología , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Regulación Neoplásica de la Expresión Génica , Humanos , Invasividad Neoplásica/patología , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Tirosina Quinasa c-Mer , Tirosina Quinasa del Receptor AxlRESUMEN
Several studies have demonstrated that specific 14-3-3 isoforms are frequently elevated in cancer and that these proteins play a role in human tumorigenesis. 14-3-3γ, an isoform recently demonstrated to function as an oncoprotein, is overexpressed in a variety of human cancers; however, its role in promoting tumorigenesis remains unclear. We previously reported that overexpression of 14-3-3γ caused the appearance of polyploid cells, a phenotype demonstrated to have profound tumor promoting properties. Here we examined the mechanism driving 14-3-3γ-induced polyploidization and the effect this has on genomic stability. Using FUCCI probes we showed that these polyploid cells appeared when diploid cells failed to enter mitosis and subsequently underwent endoreduplication. We then demonstrated that 14-3-3γ-induced polyploid cells experience significant chromosomal segregation errors during mitosis and observed that some of these cells stably propagate as tetraploids when isolated cells were expanded into stable cultures. These data lead us to conclude that overexpression of the 14-3-3γ promotes endoreduplication. We further investigated the role of 14-3-3γ in human NSCLC samples and found that its expression is significantly elevated in polyploid tumors. Collectively, these results suggests that 14-3-3γ may promote tumorigenesis through the production of a genetically unstable polyploid intermediate.
RESUMEN
Obesity and a western diet have been linked to high levels of bile acids and the development of colon cancer. Specifically, increased levels of the bile acid deoxycholic acid (DCA), an established tumor promoter, has been shown to correlate with increased development of colorectal adenomas and progression to carcinoma. Herein we investigate the mechanism by which DCA leads to EGFR-MAPK activation, a candidate mechanism by which DCA may promote colorectal tumorigenesis. DCA treated colon cancer cells exhibited strong and prolonged activation of ERK1/2 when compared to EGF treatment alone. We also showed that DCA treatment prevents EGFR degradation as opposed to the canonical EGFR recycling observed with EGF treatment. Moreover, the combination of DCA and EGF treatment displayed synergistic activity, suggesting DCA activates MAPK signaling in a non-canonical manner. Further evaluation showed that DCA treatment increased intracellular calcium levels and CAMKII phosphorylation, and that blocking calcium with BAPTA-AM abrogated MAPK activation induced by DCA, but not by EGF. Finally we showed that DCA-induced CAMKII leads to MAPK activation through the recruitment of c-Src. Taken together, we demonstrated that DCA regulates MAPK activation through calcium signaling, an alternative mechanism not previously recognized in human colon cancer cells. Importantly, this mechanism allows for EGFR to escape degradation and thus achieve a constitutively active state, which may explain its tumor promoting effects.
Asunto(s)
Señalización del Calcio/efectos de los fármacos , Ácido Desoxicólico/farmacología , Receptores ErbB/genética , Regulación Neoplásica de la Expresión Génica , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Tirosina Quinasa CSK , Calcio/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Sinergismo Farmacológico , Ácido Egtácico/análogos & derivados , Ácido Egtácico/farmacología , Factor de Crecimiento Epidérmico/farmacología , Receptores ErbB/agonistas , Receptores ErbB/metabolismo , Células HT29 , Humanos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Fosforilación , Familia-src Quinasas/genética , Familia-src Quinasas/metabolismoRESUMEN
BACKGROUND: The farnesoid X receptor (FXR) regulates bile acid (BA) metabolism and possesses tumor suppressor functions. FXR expression is reduced in colorectal tumors of subjects carrying inactivated adenomatous polyposis coli (APC). Identifying the mechanisms responsible for this reduction may offer new molecular targets for colon cancer prevention. OBJECTIVE: We investigated how APC inactivation influences the regulation of FXR expression in colonic mucosal cells. We hypothesized that APC inactivation would epigenetically repress nuclear receptor subfamily 1, group H, member 4 (FXR gene name) expression through increased CpG methylation. METHODS: Normal proximal colonic mucosa and normal-appearing adjacent colonic mucosa and colon tumors were collected from wild-type C57BL/6J and Apc-deficient (Apc(Min) (/+)) male mice, respectively. The expression of Fxr, ileal bile acid-binding protein (Ibabp), small heterodimer partner (Shp), and cyclooxygenase-2 (Cox-2) were determined by real-time polymerase chain reaction. In both normal and adjacent colonic mucosa and colon tumors, we measured CpG methylation of Fxr in bisulfonated genomic DNA. In vitro, we measured the impact of APC inactivation and deoxycholic acid (DCA) treatment on FXR expression in human colon cancer HCT-116 cells transfected with silencing RNA for APC and HT-29 cells carrying inactivated APC. RESULTS: In Apc(Min) (/+) mice, constitutive CpG methylation of the Fxrα3/4 promoter was linked to reduced (60-90%) baseline Fxr, Ibabp, and Shp and increased Cox-2 expression in apparently normal adjacent mucosa and colon tumors. Apc knockdown in HCT-116 cells increased cellular myelocytomatosis (c-MYC) and lowered (â¼50%) FXR expression, which was further reduced (â¼80%) by DCA. In human HCT-116 but not HT-29 colon cancer cells, DCA induced FXR expression and lowered CpG methylation of FXR. CONCLUSIONS: We conclude that the loss of APC function favors the silencing of FXR expression through CpG hypermethylation in mouse colonic mucosa and human colon cells, leading to reduced expression of downstream targets (SHP, IBABP) involved in BA homeostasis while increasing the expression of factors (COX-2, c-MYC) that contribute to inflammation and colon cancer.