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The outbreak of coronavirus pandemic in late 2019 posted unprecedented social-economic challenges and disruptions to societies and individuals. The "new-normal" styles of living and working could intertwined with other determinants complicating the investigation of individual's financial vulnerability. The purpose of this paper is to conduct literature survey to review and consolidate the recent scattered literatures to identify some possible factors to be considered in the research related to financial vulnerability, including pandemic's impact of COVID-19 to different aspects of personal finance issues, pandemic-driven digitisation of the economy activities, changes in financial behaviour and addiction to digital technology.
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Heart failure (HF) is a disease syndrome whose management is increasingly challenging given the aging population and efficacious management of acute cardiac events. The current treatment options within our armamentarium incompletely address the unmet needs of HF. Splanchnic nerve block (SNB) is a novel technique that targets the greater splanchnic nerve, a potential therapeutic target in HF. However, the technique confers potential adverse side effects and complications that warrant further investigations. In this review paper, we aim to discuss the inextricable role of splanchnic nerve in HF by highlighting their physiological interplay, clinical studies that have exhibited favorable hemodynamic parameters in the context of acute and chronic HF, and common side effects and possible complications from SNB.
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BACKGROUND: Chronic transportation noise exposure associates with cardiovascular events through a link involving heightened stress-associated neurobiological activity (as amygdalar metabolic activity, AmygA) on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT). Increased AmygA also associates with greater visceral adipose tissue (VAT) and type 2 diabetes mellitus (DM). While relationships between noise exposure and VAT and DM have been reported, the underlying mechanisms remain incompletely understood. We tested whether: (1) transportation noise exposure associates with greater (a) baseline and gains in VAT and (b) DM risk, and (2) heightened AmygA partially mediates the link between noise exposure and these metabolic diseases. METHODS: VAT was measured in a retrospective cohort (N = 403) who underwent clinical 18F-FDG-PET/CT. AmygA was measured in those with brain imaging (N = 238). Follow-up VAT was remeasured on available imaging (N = 67). Among individuals (N = 224) without baseline DM, incident DM was adjudicated over 2 years from clinical records. Noise (24-h average) was modeled at each individual's home address. Linear regression, survival, and mediation analyses were employed. RESULTS: Higher noise exposure (upper tertile vs. others) associated with greater: baseline VAT (standardized ß [95% confidence interval (CI)]= 0.230 [0.021, 0.438], p = 0.031), gains in VAT (0.686 [0.185, 1.187], p = 0.008 adjusted for baseline VAT), and DM (hazard ratio [95% CI]=2.429 [1.031, 5.719], p = 0.042). The paths of: ↑noise exposureâ↑AmygAâ↑baseline VAT and ↑noise exposureâ↑AmygAâ↑subsequent DM were significant (p < 0.05). CONCLUSIONS: Increased transportation noise exposure associates with greater VAT and DM. This relationship is partially mediated by stress-associated neurobiological activity. These findings suggest altered neurobiology contributes to noise exposure's link to metabolic diseases.
Subject(s)
Diabetes Mellitus, Type 2 , Intra-Abdominal Fat , Noise, Transportation , Diabetes Mellitus, Type 2/epidemiology , Fluorodeoxyglucose F18 , Humans , Intra-Abdominal Fat/diagnostic imaging , Neurobiology , Noise, Transportation/adverse effects , Positron Emission Tomography Computed Tomography , Retrospective StudiesABSTRACT
BACKGROUND: The spine surgery complexity score (SSCS), previously reported by us, is a simple grading system to predict postoperative complications and hospital length of stay (LOS). This scale is based on the technical difficulty of the spinal procedures being performed. METHODS: We performed a retrospective chart review to validate SSCS in 671 consecutive patients undergoing spine procedures at a quaternary academic hospital. RESULTS: The SSCS was predictive of the hospital LOS and postoperative complications (defined by the ClavienDindo score), based on linear regression analysis (P < 0.001 for both). CONCLUSION: Categorizing procedures according to the SSCS may enable neurosurgeons to assess surgical risk and predict longer LOS courses after spine surgery. Thus, it may prove useful in preoperative patient evaluation/ education and determining a prognosis based on surgical complexity.
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Rationale: Decreased expression and activity of endothelial nitric oxide synthase (eNOS) in response to inflammatory and metabolic insults is the hallmark of endothelial cell (EC) dysfunction that preludes the development of atherosclerosis and hypertension. We previously reported the atheroprotective properties of the ubiquitin-editing and anti-inflammatory protein A20, also known as TNFAIP3, in part through interrupting nuclear factor-kappa B (NF-κB) and interferon signaling in EC and protecting these cells from apoptosis. However, A20's effect on eNOS expression and function remains unknown. In this study, we evaluated the impact of A20 overexpression or knockdown on eNOS expression in EC, at baseline and after tumor necrosis factor (TNF) treatment, used to mimic inflammation. Methods and Results: A20 overexpression in human coronary artery EC (HCAEC) significantly increased basal eNOS mRNA (qPCR) and protein (western blot) levels and prevented their downregulation by TNF. Conversely, siRNA-induced A20 knockdown decreased eNOS mRNA levels, identifying A20 as a physiologic regulator of eNOS expression. By reporter assays, using deletion and point mutants of the human eNOS promoter, and knockdown of eNOS transcriptional regulators, we demonstrated that A20-mediated increase of eNOS was transcriptional and relied on increased expression of the transcription factor Krüppel-like factor (KLF2), and upstream of KLF2, on activation of extracellular signal-regulated kinase 5 (ERK5). Accordingly, ERK5 knockdown or inhibition significantly abrogated A20's ability to increase KLF2 and eNOS expression. In addition, A20 overexpression in HCAEC increased eNOS phosphorylation at Ser-1177, which is key for the function of this enzyme. Conclusions: This is the first report demonstrating that overexpression of A20 in EC increases eNOS transcription in an ERK5/KLF2-dependent manner and promotes eNOS activating phosphorylation. This effect withstands eNOS downregulation by TNF, preventing EC dysfunction in the face of inflammation. This novel function of A20 further qualifies its therapeutic promise to prevent/treat atherosclerosis.
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AIMS: Air pollution [i.e. particulate matter with diameter <2.5 µm (PM2.5)] is a risk factor for major adverse cardiovascular events (MACE). While PM2.5 promotes leucopoiesis and atherosclerotic inflammation in experimental models, it is unknown whether this occurs in humans. We tested in humans (a) whether PM2.5 associates with higher leucopoietic tissue activity and arterial inflammation (ArtI), (ii) whether these associations persist after accounting for the effects of potential confounders including socioeconomics, traffic noise, and risk factors, and (iii) whether these tissue effects mediate the association between air pollution and MACE. METHODS AND RESULTS: Individuals (N = 503) without cardiovascular disease (CVD) or active malignancy underwent 18 F-fluorodeoxyglucose positron emission tomography/computed tomography. Major adverse cardiovascular event was adjudicated over 5 years of follow-up. Leucopoietic tissue activity (in bone marrow and spleen) as well as ArtI were measured. Annual PM2.5 levels were assessed at each individual's home address. At baseline, higher PM2.5 associated with increased leucopoietic activity [standardized (95% CI): 0.129 (0.042, 0.215), P = 0.004] as well as ArtI [0.088 (0.006, 0.171), P = 0.036] after adjusting for CVD risk factors. Over a median 4.1 years, 40 individuals experienced MACE. PM2.5 exposure associated with MACE [Cox HR (95% CI): 1.404 (1.135, 1.737), P = 0.002], remaining significant after adjustment for CVD risk factors and other potential confounders. Mediation analysis demonstrated that increased leucopoietic activity and ArtI serially mediate the link between PM2.5 exposure and MACE. CONCLUSIONS: Higher air pollution exposure associates with heightened leucopoietic activity and ArtI and independently predicts MACE through a biological pathway that includes higher leucopoietic activity and ArtI in series.
Subject(s)
Air Pollutants , Air Pollution , Cardiovascular Diseases , Air Pollutants/adverse effects , Air Pollutants/analysis , Air Pollution/adverse effects , Air Pollution/analysis , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/etiology , Environmental Exposure/adverse effects , Environmental Exposure/analysis , Humans , Particulate Matter/adverse effects , Particulate Matter/analysis , Risk FactorsABSTRACT
OBJECTIVE: Interhospital patient transfer (IHT) of patients is common and accounts for a significant portion of health care costs, yet the variables driving neurosurgical IHT have not been systematically described. We analyzed variables that distinguished spine surgery patients who underwent IHT from patients who did not undergo IHT to report on the effect of frailty on IHT. METHODS: A retrospective chart review was performed to collect data on consecutive patients undergoing spinal procedures during 2015-2017. IHT patients were identified and compared with non-interhospital patient transfer (n-IHT) patients to identify factors that distinguished the 2 patient groups using multivariate regression analysis. Studied variables included case complexity, frailty (modified frailty index), age, insurance status, and baseline demographic variables. Postoperative outcomes affected by transfer status were identified in binary regression analysis. RESULTS: During 2015-2017, there were 595 n-IHT and 76 IHT spine surgery patients (N = 671). Increased frailty (modified frailty index ≥3; odds ratio = 2.4, P = 0.01) and increased spine surgery complexity (spine surgery complexity score ≥2; odds ratio = 2.57, P = 0.002) were independent risk factors associated with IHT. IHT was an independent risk factor for increased hospital length of stay and increased postoperative complications (Clavien-Dindo scale; P < 0.001). CONCLUSIONS: IHT patients comprise a more frail and surgically complex surgical spine population compared with n-IHT patients. IHT was also an independent risk factor for increased complications and length of stay after spine surgery. Patients' insurance status and age did not distinguish between IHT and n-IHT groups. This is the first report in any specialty to demonstrate increasing frailty is associated with IHT.
Subject(s)
Patient Transfer , Spine/surgery , Adult , Age Factors , Aged , Demography , Female , Frail Elderly , Frailty , Humans , Insurance Coverage , Length of Stay , Male , Middle Aged , Neurosurgical Procedures , ROC Curve , Retrospective Studies , Risk Factors , Treatment OutcomeABSTRACT
AIMS: Chronic noise exposure associates with increased cardiovascular disease (CVD) risk; however, the role of confounders and the underlying mechanism remain incompletely defined. The amygdala, a limbic centre involved in stress perception, participates in the response to noise. Higher amygdalar metabolic activity (AmygA) associates with increased CVD risk through a mechanism involving heightened arterial inflammation (ArtI). Accordingly, in this retrospective study, we tested whether greater noise exposure associates with higher: (i) AmygA, (ii) ArtI, and (iii) risk for major adverse cardiovascular disease events (MACE). METHODS AND RESULTS: Adults (N = 498) without CVD or active cancer underwent clinical 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Amygdalar metabolic activity and ArtI were measured, and MACE within 5 years was adjudicated. Average 24-h transportation noise and potential confounders were estimated at each individual's home address. Over a median 4.06 years, 40 individuals experienced MACE. Higher noise exposure (per 5 dBA increase) predicted MACE [hazard ratio (95% confidence interval, CI) 1.341 (1.147-1.567), P < 0.001] and remained robust to multivariable adjustments. Higher noise exposure associated with increased AmygA [standardized ß (95% CI) 0.112 (0.051-0.174), P < 0.001] and ArtI [0.045 (0.001-0.090), P = 0.047]. Mediation analysis suggested that higher noise exposure associates with MACE via a serial mechanism involving heightened AmygA and ArtI that accounts for 12-26% of this relationship. CONCLUSION: Our findings suggest that noise exposure associates with MACE via a mechanism that begins with increased stress-associated limbic (amygdalar) activity and includes heightened arterial inflammation. This potential neurobiological mechanism linking noise to CVD merits further evaluation in a prospective population.
Subject(s)
Cardiovascular Diseases , Noise, Transportation , Adult , Cardiovascular Diseases/etiology , Fluorodeoxyglucose F18 , Humans , Noise, Transportation/adverse effects , Prospective Studies , Retrospective Studies , Risk FactorsABSTRACT
Multiple sclerosis (MS) is a neuroinflammatory disease with a relapsing-remitting disease course at early stages, distinct lesion characteristics in cortical grey versus subcortical white matter and neurodegeneration at chronic stages. Here we used single-nucleus RNA sequencing to assess changes in expression in multiple cell lineages in MS lesions and validated the results using multiplex in situ hybridization. We found selective vulnerability and loss of excitatory CUX2-expressing projection neurons in upper-cortical layers underlying meningeal inflammation; such MS neuron populations exhibited upregulation of stress pathway genes and long non-coding RNAs. Signatures of stressed oligodendrocytes, reactive astrocytes and activated microglia mapped most strongly to the rim of MS plaques. Notably, single-nucleus RNA sequencing identified phagocytosing microglia and/or macrophages by their ingestion and perinuclear import of myelin transcripts, confirmed by functional mouse and human culture assays. Our findings indicate lineage- and region-specific transcriptomic changes associated with selective cortical neuron damage and glial activation contributing to progression of MS lesions.
Subject(s)
Cell Lineage , Multiple Sclerosis/pathology , Neurons/pathology , Adult , Animals , Astrocytes/metabolism , Astrocytes/pathology , Autopsy , Cryopreservation , Female , Homeodomain Proteins/metabolism , Humans , Macrophages/metabolism , Macrophages/pathology , Male , Mice , Microglia/metabolism , Microglia/pathology , Middle Aged , Multiple Sclerosis/genetics , Myelin Sheath/metabolism , Neurons/metabolism , Oligodendroglia/metabolism , Oligodendroglia/pathology , Phagocytosis , RNA, Small Nuclear/analysis , RNA, Small Nuclear/genetics , RNA-Seq , Transcriptome/geneticsABSTRACT
BACKGROUND: Lower socioeconomic status (SES) associates with a higher risk of major adverse cardiac events (MACE) via mechanisms that are not well understood. OBJECTIVES: Because psychosocial stress is more prevalent among those with low SES, this study tested the hypothesis that stress-associated neurobiological pathways involving up-regulated inflammation in part mediate the link between lower SES and MACE. METHODS: A total of 509 individuals, median age 55 years (interquartile range: 45 to 66 years), underwent clinically indicated whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging and met pre-defined inclusion criteria, including absence of known cardiovascular disease or active cancer. Baseline hematopoietic tissue activity, arterial inflammation, and in a subset of 289, resting amygdalar metabolism (a measure of stress-associated neural activity) were quantified using validated 18F-fluorodeoxyglucose positron emission tomography/computed tomography methods. SES was captured by neighborhood SES factors (e.g., median household income and crime). MACE within 5 years of imaging was adjudicated. RESULTS: Over a median 4.0 years, 40 individuals experienced MACE. Baseline income inversely associated with amygdalar activity (standardized ß: -0.157 [95% confidence interval (CI): -0.266 to -0.041]; p = 0.007) and arterial inflammation (ß: -0.10 [95% CI: -0.18 to -0.14]; p = 0.022). Further, income associated with subsequent MACE (standardized hazard ratio: 0.67 [95% CI: 0.47 to 0.96]; p = 0.029) after multivariable adjustments. Mediation analysis demonstrated that the path of: ↓ neighborhood income to ↑ amygdalar activity to ↑ bone marrow activity to ↑ arterial inflammation to ↑ MACE was significant (ß: -0.01 [95% CI: -0.06 to -0.001]; p < 0.05). CONCLUSIONS: Lower SES: 1) associates with higher amygdalar activity; and 2) independently predicts MACE via a serial pathway that includes higher amygdalar activity, bone marrow activity, and arterial inflammation. These findings illuminate a stress-associated neurobiological mechanism by which SES disparities may potentiate adverse health outcomes.
Subject(s)
Amygdala/physiopathology , Arteritis/etiology , Heart Diseases/etiology , Social Class , Stress, Psychological/complications , Adult , Aged , Amygdala/diagnostic imaging , Arteritis/diagnostic imaging , Arteritis/psychology , Female , Fluorodeoxyglucose F18 , Heart Diseases/psychology , Hematopoiesis , Humans , Longitudinal Studies , Male , Middle Aged , Positron Emission Tomography Computed Tomography , Retrospective Studies , Stress, Psychological/diagnostic imaging , Stress, Psychological/physiopathologyABSTRACT
CONTEXT: Epidemiologic data link psychological stress to adiposity. The underlying mechanisms remain uncertain. OBJECTIVES: To test whether (i) higher activity of the amygdala, a neural center involved in the response to stress, associates with greater visceral adipose tissue (VAT) volumes and (ii) this association is mediated by increased bone marrow activity. SETTING: Massachusetts General Hospital, Boston, Massachusetts. PATIENTS: Two hundred forty-six patients without active oncologic, cardiovascular, or inflammatory disease who underwent clinical 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging were studied. VAT imaging was repeated â¼1 year later in 68 subjects. DESIGN: Metabolic activity of the amygdala (AmygA), hematopoietic tissue activity, and adiposity volumes were measured with validated methods. MAIN OUTCOME MEASURE: The relationship between AmygA and baseline and follow-up VAT. RESULTS: AmygA associated with baseline body mass index (standardized ß = 0.15; P = 0.01), VAT (0.19; P = 0.002), and VAT/subcutaneous adipose tissue ratio (0.20; P = 0.002), all remaining significant after adjustment for age and sex. AmygA also associated with bone marrow activity (0.15; P = 0.01), which in turn associated with VAT (0.34; P < 0.001). Furthermore, path analysis showed that 48% of the relationship between AmygA and baseline VAT was mediated by increased bone marrow activity (P = 0.007). Moreover, AmygA associated with achieved VAT after 1 year (P = 0.02) after adjusting for age, sex, and baseline VAT. CONCLUSIONS: These results suggest a neurobiological pathway involving the amygdala and bone marrow linking psychosocial stress to adiposity in humans. Future studies should test whether targeting this mechanism attenuates adiposity and its complications.
Subject(s)
Amygdala/metabolism , Bone Marrow/metabolism , Intra-Abdominal Fat/diagnostic imaging , Obesity, Abdominal/diagnostic imaging , Stress, Psychological/complications , Adiposity/physiology , Adult , Aged , Amygdala/diagnostic imaging , Amygdala/physiopathology , Female , Fluorodeoxyglucose F18/administration & dosage , Follow-Up Studies , Humans , Male , Middle Aged , Obesity, Abdominal/etiology , Obesity, Abdominal/physiopathology , Positron Emission Tomography Computed Tomography , Retrospective Studies , Stress, Psychological/physiopathologyABSTRACT
While it is established that psychosocial stress increases the risk of developing diabetes mellitus (DM), two key knowledge gaps remain: 1) the neurobiological mechanisms that are involved in mediating that risk, and 2) the role, if any, that adiposity plays in that mechanism. We tested the hypotheses that: 1) metabolic activity in the amygdala (AmygA), a key center involved in the neurobiological response to stress, associates with subsequent DM risk, and 2) this association is independent of adiposity. AmygA and adipose tissue volumes were measured, and serial blood assessments for DM were obtained in 232 subjects who underwent combined 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging. Higher baseline AmygA predicted subsequent, new-onset DM, independently of adiposity and other DM risk factors. Furthermore, higher adiposity only increased DM risk in the presence of higher AmygA. In a separate cross-sectional cohort, higher AmygA associated with higher insulin resistance. Accordingly, the current study shows, for the first time, that activity in a stress-responsive neural region predicts the onset of DM. Further, we observed that this neurobiological activity acts independently of, but also synergistically with adiposity to increase DM risk. These findings suggest novel therapeutic targets to help manage and possibly prevent DM.
Subject(s)
Adiposity/physiology , Amygdala/metabolism , Diabetes Mellitus, Type 2/diagnosis , Adult , Aged , Amygdala/diagnostic imaging , Biomarkers/metabolism , Cross-Sectional Studies , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/metabolism , Female , Fluorodeoxyglucose F18/pharmacokinetics , Humans , Incidence , Longitudinal Studies , Male , Middle Aged , Obesity/complications , Obesity/diagnosis , Obesity/epidemiology , Obesity/metabolism , Positron Emission Tomography Computed Tomography , Predictive Value of Tests , Prognosis , Retrospective StudiesABSTRACT
BACKGROUND: The dismal prognosis of patients with glioblastoma (GBM) is attributed to a rare subset of cancer stem cells that display characteristics of tumor initiation, growth, and resistance to aggressive treatment involving chemotherapy and concomitant radiation. Recent research on the substantial role of epigenetic mechanisms in the pathogenesis of cancers has prompted the investigation of the enzymatic modifications of histone proteins for therapeutic drug targeting. In this work, we have examined the function of Krüppel-like factor 9 (KLF9), a transcription factor, in chemotherapy sensitization to histone deacetylase inhibitors (HDAC inhibitors). METHODS: Since GBM neurosphere cultures from patient-derived gliomas are enriched for GBM stem-like cells (GSCs) and form highly invasive and proliferative xenografts that recapitulate the features demonstrated in human patients diagnosed with GBM, we established inducible KLF9 expression systems in these GBM neurosphere cells and investigated cell death in the presence of epigenetic modulators such as histone deacetylase (HDAC) inhibitors. RESULTS: We demonstrated that KLF9 expression combined with HDAC inhibitor panobinostat (LBH589) dramatically induced glioma stem cell death via both apoptosis and necroptosis in a synergistic manner. The combination of KLF9 expression and LBH589 treatment affected cell cycle by substantially decreasing the percentage of cells at S-phase. This phenomenon is further corroborated by the upregulation of cell cycle inhibitors p21 and p27. Further, we determined that KLF9 and LBH589 regulated the expression of pro- and anti- apoptotic proteins, suggesting a mechanism that involves the caspase-dependent apoptotic pathway. In addition, we demonstrated that apoptosis and necrosis inhibitors conferred minimal protective effects against cell death, while inhibitors of the necroptosis pathway significantly blocked cell death. CONCLUSIONS: Our findings suggest a detailed understanding of how KLF9 expression in cancer cells with epigenetic modulators like HDAC inhibitors may promote synergistic cell death through a mechanism involving both apoptosis and necroptosis that will benefit novel combinatory antitumor strategies to treat malignant brain tumors.
Subject(s)
Antineoplastic Agents/pharmacology , Glioblastoma/metabolism , Histone Deacetylase Inhibitors/pharmacology , Kruppel-Like Transcription Factors/antagonists & inhibitors , Neoplastic Stem Cells/drug effects , Neoplastic Stem Cells/metabolism , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Cell Death/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Drug Synergism , Flow Cytometry , Gene Expression , Glioblastoma/genetics , Humans , Kruppel-Like Transcription Factors/genetics , Kruppel-Like Transcription Factors/metabolism , Panobinostat/pharmacologySubject(s)
Atherosclerosis/diagnostic imaging , Inflammation/diagnostic imaging , Multimodal Imaging/methods , Vascular Calcification/diagnostic imaging , Atherosclerosis/pathology , Humans , Inflammation/pathology , Plaque, Atherosclerotic , Predictive Value of Tests , Prognosis , Reproducibility of Results , Vascular Calcification/pathologyABSTRACT
Mitochondria are vital organelles that supply ATP and other energy metabolites to meet the bioenergetics demands of the cell. In environments of stress or increased energy requirement, mitochondria are highly dynamic and can undergo biogenesis, fusion/fission, or autophagy. The transcription factor family, Kruppel-Like Factor (KLF), is necessary to carry out normal cellular processes from proliferation to differentiation. Recently, its importance in metabolic homeostasis in various tissue types has gained much attention. A handful of evidence supports KLF4's involvement in regulating mitochondrial homeostasis in both healthy and cancer cells. In this review, we aim to summarize the available literature that demonstrates KLF4's ability to modulate the mitochondrial life cycle in: Cardiac tissue, in which KLF4-knockdown subsequently leads to Heart Failure (HF), andGlioblastoma (GBM), where its expression promotes extensive mitochondrial fusion and offers mild cell protection under serum-deprivation.
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The purpose of this study was to assess the potential therapeutic effect of positrons emitted by 18F-2-Deoxy-2-Fluoro-D-Glucose (18F-FDG) on pancreatic cancer cells and elucidate its underlying mechanisms. Pancreatic cancer cells were incubated with different radioactive concentrations of 18F-FDG and evaluated for anti-cancer properties and underlining mechanisms. In addition, three groups of tumor-bearing mice were treated with different doses of 18F-FDG weekly, the tumor growth rate was calculated, and the mice were imaged by positron emission tomography (PET) with 18F-FDG before and after treatment. The presence of apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stain and immunohistochemistry analysis. All treated groups exhibited positron-inhibited proliferation and positron-induced apoptosis compared with the control group in vitro. Further, we noted that higher treatment dose correlated with a better treatment response. In vivo, the high dose administration of 18F-FDG reduced tumor growth and prolonged the survival of treated mice compared with the control group with no change in the behavior or normal tissues of the mice. Immunohistochemical analysis and TUNEL stain showed more apoptotic cells than that in control group. The results demonstrated that positron radiation inhibited the proliferation and induced apoptosis of pancreatic cancer cells in vitro and in vivo, via an endogenous mitochondria-mediated signaling pathway.
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Altered DNA methylation status is associated with human diseases and cancer; however, the underlying molecular mechanisms remain elusive. We previously identified many human transcription factors, including Krüppel-like factor 4 (KLF4), as sequence-specific DNA methylation readers that preferentially recognize methylated CpG (mCpG), here we report the biological function of mCpG-dependent gene regulation by KLF4 in glioblastoma cells. We show that KLF4 promotes cell adhesion, migration, and morphological changes, all of which are abolished by R458A mutation. Surprisingly, 116 genes are directly activated via mCpG-dependent KLF4 binding activity. In-depth mechanistic studies reveal that recruitment of KLF4 to the methylated cis-regulatory elements of these genes result in chromatin remodeling and transcription activation. Our study demonstrates a new paradigm of DNA methylation-mediated gene activation and chromatin remodeling, and provides a general framework to dissect the biological functions of DNA methylation readers and effectors.
Subject(s)
Cell Movement , DNA Methylation , Gene Expression Regulation , Kruppel-Like Transcription Factors/metabolism , Regulatory Sequences, Nucleic Acid , Transcriptional Activation , Cell Line, Tumor , Chromatin Assembly and Disassembly , Humans , Kruppel-Like Factor 4 , Protein BindingABSTRACT
BACKGROUND: Glioblastoma (GBM) is the most frequent and aggressive primary brain tumor in adults. Recent research on cancer stroma indicates that the brain microenvironment plays a substantial role in tumor malignancy and treatment responses to current antitumor therapy. In this work, we have investigated the effect of alterations in brain tumor extracellular matrix tenascin-C (TNC) on brain tumor growth patterns including proliferation and invasion. METHODS: Since intracranial xenografts from patient-derived GBM neurospheres form highly invasive tumors that recapitulate the invasive features demonstrated in human patients diagnosed with GBM, we studied TNC gain-of-function and loss-of function in these GBM neurospheres in vitro and in vivo. RESULTS: TNC loss-of-function promoted GBM neurosphere cell adhesion and actin cytoskeleton organization. Yet, TNC loss-of-function or exogenous TNC had no effect on GBM neurosphere cell growth in vitro. In animal models, decreased TNC in the tumor microenvironment was accompanied by decreased tumor invasion and increased tumor proliferation, suggesting that TNC regulates the "go-or-grow" phenotypic switch of glioma in vivo. We demonstrated that decreased TNC in the tumor microenvironment modulated behaviors of stromal cells including endothelial cells and microglia, resulting in enlarged tumor blood vessels and activated microglia in tumors. We further demonstrated that tumor cells with decreased TNC expression are sensitive to anti-proliferative treatment in vitro. CONCLUSION: Our findings suggest that detailed understanding of how TNC in the tumor microenvironment influences tumor behavior and the interactions between tumor cells and surrounding nontumor cells will benefit novel combinatory antitumor strategies to treat malignant brain tumors.