STK17A is a relatively uncharacterized member of the death-associated protein family of serine/threonine kinases which have previously been associated with cell death and apoptosis. Our prior work established that STK17A is a novel p53 target gene that is induced by a variety of DNA damaging agents in a p53-dependent manner. In this study we have uncovered an additional, unanticipated role for STK17A as a candidate promoter of cell proliferation and survival in glioblastoma (GBM). Unexpectedly, it was found that STK17A is highly overexpressed in a grade-dependent manner in gliomas compared to normal brain and other cancer cell types with the highest level of expression in GBM. Knockdown of STK17A in GBM cells results in a dramatic alteration in cell shape that is associated with decreased proliferation, clonogenicity, migration, invasion and anchorage independent colony formation. STK17A knockdown also sensitizes GBM cells to genotoxic stress. STK17A overexpression is associated with a significant survival disadvantage among patients with glioma which is independent of age, molecular phenotype, IDH1 mutation, PTEN loss, and alterations in the p53 pathway and partially independent of grade. In summary, we demonstrate that STK17A provides a proliferative and survival advantage to GBM cells and is a potential target to be exploited therapeutically in patients with glioma.
Background. Orthotopic lung transplantation is now widely performed in patients with advanced lung disease. Patients with moderate or severe ventricular systolic dysfunction are typically excluded from lung transplantation; however, there is a paucity of data regarding the prognostic significance of abnormal left ventricular diastolic function and elevated pretransplant pulmonary pressures. Methods. We reviewed the characteristics of 111 patients who underwent bilateral and unilateral lung transplants from 200 to 2009 in order to evaluate the prognostic significance of preoperative markers of diastolic function, including invasively measured pulmonary capillary wedge pressure (PCWP) and echocardiographic variables of diastolic dysfunction including mitral A > E and A′ > E′. Results. Out of 111 patients, 62 were male (56%) and average age was 54.0 ± 10.5 years. Traditional echocardiographic Doppler variables of abnormal diastolic function, including A′ > E′ and A > E, did not predict adverse events (P = 0.49). Mildly elevated pretransplant PCWP (16–20 mmHg) and moderately/severely elevated PCWP (>20 mmHg) were not associated with adverse clinical events after transplant (P = 0.30). Additionally, all clinical endpoints did not show any statistical significance between the two groups. Conclusions. Pre-lung transplant invasive and echocardiographic findings of elevated pulmonary pressures and abnormal left ventricular diastolic function are not predictive of adverse posttransplant clinical events.
To study whether use of β-blockers increases survival in patients with malignant melanoma because experimental data suggest that catecholamine hormones may be involved in stimulating the aggressiveness of malignant melanoma.
A total of 4,179 patients diagnosed with malignant melanoma in Denmark with a median follow-up of 4.9 years and identified in the Danish Cancer Registry participated. Data on β-blocker use, comorbidity, and survival were obtained from medical and administrative databases. Cox proportional hazards models were used to estimate HRs for all-cause mortality with 95% CIs with adjustment for prognostic factors.
A total of 372 (8.9%) patients with malignant melanoma were treated with β-blockers within 90 days of melanoma diagnosis. The median β-blocker duration for exposure within 90 days of melanoma diagnosis, more than 90 days, and no prior exposure was 7.6, 1.4, and 0 years, respectively. The patients receiving β-blockers were older, had more comorbidities, and more cardiovascular and psychotropic drug user than the patients receiving no β-blockers prior to melanoma diagnosis. After adjustment for age and comorbidity index, the HR for melanoma death was 0.87 (95% CI: 0.64–1.20) and for all-cause mortality was 0.81 (95% CI: 0.67–0.97).
Increased survival time of patients with melanoma receiving β-blockers suggests that this class of drugs may hold promise in treatment strategy for these patients.
The observations described here suggest that catecholamines may retard melanoma progression and that β-blockers may have unrecognized potential as a therapeutic intervention for melanoma.
Experimental data suggest that catecholamine hormones are involved in stimulating the aggressiveness of ovarian cancer, but few population-based studies have examined this association. We therefore conducted a population-based cohort study to examine whether ß-blockers affect mortality following ovarian cancer diagnosis.
We used the Danish Cancer Registry to identify all patients diagnosed with ovarian cancer in northern Denmark between 1999 and 2010 (n=6,626). Data on medication use, comorbidity, and survival were obtained from medical databases. According to the last redeemed prescription before diagnosis, ß-blocker use was categorized as current (within ≤90 days), previous (>90 days) or never. We used Cox proportional hazards regression to calculate hazard ratios (HRs) for all-cause mortality with 95% confidence intervals (CIs) adjusting for confounding factors.
Among the ovarian cancer patients, 373 (5.6%) were current, 87 (1.3%) previous, and 6,166 (93.1%) were nonusers of ß-blockers. Median duration of use was 19.0 months among current users and 43.0 months among previous users. Median follow-up was 2.55 years (IQR: 0.81-9.23). Nonusers and current users of ß-blockers had similar comorbidity burden whereas previous users had moderate comorbidity more frequently. Compared with nonusers, the adjusted HR was 1.17 (95% CI: 1.02–1.34) for current users and 1.18 (95% CI: 0.90–1.55) for previous users. Secondary analyses stratifying by cancer stage and duration of ß-blocker use supported the overall results.
We found no evidence that ß-blocker use was associated with decreased mortality following ovarian cancer diagnosis.
Background and Purpose
Ultrasound measurements of arterial stiffness are associated with atherosclerosis risk factors, but limited data exist on their association with incident cardiovascular events. We evaluated the association of carotid ultrasound derived arterial stiffness measures with incident coronary heart disease (CHD) and ischemic stroke in the ARIC study.
Carotid arterial strain (CAS) and compliance (AC), distensibility (AD) and stiffness indices (SI), pressure-strain (Ep) and Young’s elastic moduli (YEM) were measured in 10,407 individuals using ultrasound. Hazard ratios for incident CHD (myocardial infarction [MI], fatal CHD, coronary revascularization) and stroke in minimally adjusted (age, sex, center, race) and fully adjusted models (minimally adjusted model + diabetes, height, weight, total cholesterol, high-density lipoprotein cholesterol, tobacco use, systolic blood pressure, antihypertensive medication use, and carotid intima-media thickness (CIMT) were calculated.
The mean age was 55.3 years. Over a mean follow up of 13.8 years, 1,267 incident CHD and 383 ischemic stroke events occurred. After full adjustment for risk factors and CIMT, all arterial stiffness parameters [CAS HR (95% confidence interval [CI]) =1.14 (1.02, 1.28); AD HR=1.19 (1.02, 1.39); SI HR=1.14 (1.04, 1.25); Ep HR=1.17 (1.06, 1.28); YEM HR=1.13 (1.03, 1.24)], except arterial compliance HR=1.02 (0.90, 1.16), were significantly associated with incident stroke but not with CHD.
After adjusting for cardiovascular risk factors, ultrasound measures of carotid arterial stiffness are associated with incident ischemic stroke but not incident CHD events, despite that the 2 outcomes sharing similar risk factors.
arterial stiffness; carotid ultrasound; coronary heart disease; stroke; ARIC
Increased arterial stiffness has been shown to be associated with aging and cardiovascular risk factors. Speckle-tracking algorithms are being used to measure myocardial strain. We evaluated if speckle-tracking could be used to measure carotid arterial wall strain (CAS) reproducibly in healthy volunteers and then examined if CAS was lesser in individuals with diabetes.
Bilateral electrocardiography-gated ultrasound scans of the distal common carotid arteries [D-CCA] (3 cardiac cycles, 14 MHz linear probe, mean 78.7 [Standard deviation (SD) 8.9]) frames per second were performed twice (2–4 days apart) on 10 healthy volunteers to test repeatability. Differences in CAS between healthy (n=20) and diabetic subjects (n=21) were examined. Peak CAS was measured in each of 6 equal segments and averages of all segments (i.e., global average), of the 3 nearest the probe, and of the 3 farthest from the probe (i.e., far wall average) were obtained.
Global CAS (intraclass correlation coefficient [ICC]=0.40) and far wall average (ICC=0.63) had the greatest test-retest reliability. The global and far wall averaged CAS were lower in diabetics (4.29% [Standard Error (SE) 0.27%]; 4.30% [SE 0.44%], respectively) than in controls (5.48% [SE 0.29%], p=0.001; 5.58% [SE 0.44%], p=0.003, respectively). This difference persisted after adjustment for age, gender, race, and hemodynamic parameters.
Speckle-tracking for measuring carotid arterial wall strain is feasible and modestly reliable. Diabetic subjects had a lower carotid arterial wall strain obtained with speckle-tracking when compared with healthy controls.
To evaluate whether a novel GPS-like position-sensing technology will enable accurate co-registration of images between imaging modalities.
Co-registration of images obtained by different imaging modalities will allow for comparison and fusion between imaging modalities, and therefore has significant clinical and research implications. We compared US and MR images of carotid endarterectomy (CEA) specimens using a novel position-sensing technology that uses an electromagnetic (EM) transmitter and sensors mounted on a US transducer. We then evaluated in vivo US-US and US-MRI co-registration.
Thirteen CEA specimens underwent 3.0 Tesla MRI, after which images were uploaded to a LOGIQ E9 3D (GE Healthcare) US system and registered by identifying 2–3 common points. A similar method was used to evaluate US-MRI co-registration in patients with carotid atherosclerosis. For carotid intima-media thickness (C-IMT) measurements, ten volunteers underwent bilateral carotid US scans co-registered to 3D US maps created on the initial visit, with a repeat scan 2 days later.
For the CEA specimens, there was a mean 20 (standard error [SE] 2.0) frames per MRI slice. The mean frame difference, over 33 registration markers, between MR and US images for Readers 1 and 2 was −2.82 ± 19.32 (mean ± 95% confidence interval [CI]) frames and 2.09 ± 14.68 (mean ± 95% CI) frames, respectively. The US-MRI intraclass correlation coefficients (ICC) for the first and second readers were 0.995 and 0.997, respectively. For patients with carotid atherosclerosis, the mean US frames per MRI slice (9 [SE 2.3]) was within range of that observed with CEA specimens. Inter-visit, intra-reader, and inter-reader reproducibility of C-IMT measurements were consistently high (side-averaged ICC >0.9).
Accurate co-registration between US and other modalities is feasible with a GPS-like technology, which has significant clinical and research applicability.
Patients with Mild Cognitive Impairment (MCI) are at high risk of progression to Alzheimer’s dementia. Identifying MCI individuals with high likelihood of conversion to dementia and the associated biosignatures has recently received increasing attention in AD research. Different biosignatures for AD (neuroimaging, demographic, genetic and cognitive measures) may contain complementary information for diagnosis and prognosis of AD.
We have conducted a comprehensive study using a large number of samples from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to test the power of integrating various baseline data for predicting the conversion from MCI to probable AD and identifying a small subset of biosignatures for the prediction and assess the relative importance of different modalities in predicting MCI to AD conversion. We have employed sparse logistic regression with stability selection for the integration and selection of potential predictors. Our study differs from many of the other ones in three important respects: (1) we use a large cohort of MCI samples that are unbiased with respect to age or education status between case and controls (2) we integrate and test various types of baseline data available in ADNI including MRI, demographic, genetic and cognitive measures and (3) we apply sparse logistic regression with stability selection to ADNI data for robust feature selection.
We have used 319 MCI subjects from ADNI that had MRI measurements at the baseline and passed quality control, including 177 MCI Non-converters and 142 MCI Converters. Conversion was considered over the course of a 4-year follow-up period. A combination of 15 features (predictors) including those from MRI scans, APOE genotyping, and cognitive measures achieves the best prediction with an AUC score of 0.8587.
Our results demonstrate the power of integrating various baseline data for prediction of the conversion from MCI to probable AD. Our results also demonstrate the effectiveness of stability selection for feature selection in the context of sparse logistic regression.
A 21-year-old man with no known medical history presented with substernal chest pain. Serial 12-lead electrocardiography showed dynamic ST-segment elevations in the anterolateral leads. Emergent coronary angiography revealed diffuse coronary aneurysmal disease and thrombotic occlusion of the left anterior descending coronary artery. The patient underwent urgent coronary artery bypass grafting. Subsequent imaging showed intracerebral aneurysms that involved his right and left middle cerebral arteries. The incidence, multiple causes, and proposed mechanisms of coronary artery aneurysmal formation are discussed, as is the rare association of these lesions with extracardiac arterial aneurysms.
This association between coronary and extracardiac aneurysms is a phenomenon that warrants further study to determine its prevalence and possible causes. Findings could influence recommendations for further screening of patients diagnosed with coronary aneurysmal disease.
Acute coronary syndrome; cerebrovas-cular aneurysms; congenital heart disease; coronary aneurysm/etiology; coronary vessel anomalies; dilatation, pathologic/etiology; intra-cranial aneurysm; Kawasaki disease
The objective of identifying transcriptional regulatory networks is to provide insights as to what governs an organism’s long term response to external stimuli. We explore the coupling of the living cell array (LCA), a novel microfluidics device which utilizes fluorescence levels as a surrogate for transcription factor activity with reverse Euler deconvolution (RED) a computational technique proposed in this work to decipher the dynamics of the interactions. It is hypothesized that these two methods will allow us to first assess the underlying network architecture associated with the transcription factor network as well as specific mechanistic consequences of transcription factor activation such as receptor dimerization or tolerance.
The overall approach identifies evidence of time-lagged response which may be indicative of mechanisms such as receptor dimerization, tolerance mechanisms which are evidence of various receptor mediated dynamics, and feedback loops which regulate the response of an organism to changing environmental conditions. Furthermore, through the exploration of multiple network architectures, we were able to obtain insights as to the role each transcription factor plays in the overall response and their overall redundancy in the organism’s response to external perturbations. Thus, the LCA along with the proposed analysis technique is a valuable tool for identifying the possible architectures and mechanisms underlying the transcriptional response.
Systems biology; Network reconstruction
Psychological stress-associated immune dysregulation has been shown to disrupt the steady state expression and reactivate latent herpes viruses. One such virus is the Epstein Barr virus (EBV), which is associated with several human malignancies. EBV infects >90% of people living in North America and persists for life in latently infected cells. Although several studies have shown that glucocorticoids (GCs) can directly induce reactivation of the latent virus, the mechanism of stress hormone involvement in the control of EBV gene expression is not well understood. In this study, we tested the hypothesis that GCs can induce the latent EBV genome to lytically replicate through the induction of the EBV immediate early gene BZLF1 which encodes the lytic transactivator protein ZEBRA. We show a dose-dependent upregulation of BZLF1 mRNA expression by hydrocortisone (HC) and dexamethasone (Dex) in Daudi cells, an EBV genome positive Burkitt’s lymphoma cell line, and Dex-induction of the early gene products BLLF3 (encoding for the EBV dUTPase) and BALF5 (encoding for the EBV DNA polymerase). We show that Daudi cells express glucocorticoid receptors (GR) that mediate Dex-dependent upregulation of BZLF1 mRNA levels. This effect was inhibited by both the glucocorticoid receptor antagonist RU486 and by cycloheximide. The results suggest that GCs, in addition to inducing stress-related immune dysregulation, can mediate latent EBV reactivation through the induction of the BZLF1 gene.
Epstein Barr virus; glucocorticoids; glucocorticoid receptor; herpesvirus reactivation; psychological stress
Basal cell carcinoma (BCC) tumors are the most common skin cancer and are highly immunogenic.
The goal of this study was to assess how immune-cell related gene expression in an initial BCC tumor biopsy was related to the appearance of subsequent BCC tumors.
Materials and Methods
Levels of mRNA for CD3ε (a T-cell receptor marker), CD25 (the alpha chain of the interleukin (IL)-2 receptor expressed on activated T-cells and B-cells), CD68 (a marker for monocytes/macrophages), the cell surface glycoprotein intercellular adhesion molecule-1 (ICAM-1), the cytokine interferon-γ (IFN-γ) and the anti-inflammatory cytokine IL-10 were measured in BCC tumor biopsies from 138 patients using real-time PCR.
The median follow-up was 26.6 months, and 61% of subjects were free of new BCCs two years post-initial biopsy. Patients with low CD3ε CD25, CD68, and ICAM-1 mRNA levels had significantly shorter times before new tumors were detected (p = 0.03, p = 0.02, p = 0.003, and p = 0.08, respectively). Furthermore, older age diminished the association of mRNA levels with the appearance of subsequent tumors.
Our results show that levels of CD3ε, CD25, CD68, and ICAM-1 mRNA in BCC biopsies may predict risk for new BCC tumors.
catecholamines; adrenergic receptors; β-blockers; tumor progression; angiogenesis; invasion/metastasis
Melanoma is a common and deadly tumor that upon metastasis to the central nervous system (CNS) has a median survival duration of less than 6 months. Activation of the signal transducer and activator of transcription 3 (STAT3) has been identified as a key mediator that drives the fundamental components of melanoma malignancy, including immune suppression in melanoma patients. We hypothesized that WP1193, a novel inhibitor of STAT3 signaling, would enhance the anti-tumor activity of IFN-α against metastatic melanoma.
Combinational therapy of STAT3 blockade agents with IFN-α was investigated in a metastatic and an established syngeneic intracerebral murine tumor model of melanoma. The immunological in vivo mechanisms of efficacy were investigated by T cell and NK cell cytotoxic assays.
IFN-α immunotherapy was synergistic with WP1193 demonstrating marked in vivo efficacy against metastatic and established intracerebral melanoma. At autopsy, it was noted that there was a decreased trend in mice with melanoma developing leptomeningeal disease (LMD) treated with combinational therapy. The combinational approach enhanced both NK and T cell-mediated anti-tumor cytotoxicity.
The immune modulatory effects of STAT3 blockade can enhance the therapeutic efficacy of IFN-α immunotherapy by enhancing both innate and adaptive cytotoxic T cell activities. This combination therapy has the potential in the treatment of metastatic melanoma that is typically refractory to this type of immune therapeutic approach.
Melanoma; IFN-α; STAT3; leptomeningeal disease; CD8+ T cell
The study aim was to evaluate the relation between the Framingham risk score (FRS) and the presence of coronary risk factors to coronary microcirculatory vasodilator function in patients with early coronary atherosclerosis.
Methods and results
We evaluated 1063 patients (age: 50 ± 12 years, 676 (64%) females) without significant narrowing (<30%) on coronary angiography who underwent invasive assessment of coronary endothelial function. Coronary blood flow (CBF) in response to the endothelium-dependent vasodilator acetylcholine was evaluated as well as the microvascular (endothelium-independent) coronary flow reserve (CFR) in response to intracoronary adenosine. Coronary blood flow and CFR were analysed in relation to the FRS and the presence of traditional and novel risk factors. The estimated 10 years risk in this group was 5.4 ± 5.2%. Higher FRS was associated with lower CBF in men (P = 0.008), and was a univariate predictor of lower CFR (P = 0.012) in all patients. Multivariable analysis identified a higher FRS (P < 0.001), female sex (P < 0.001) and a positive family history of coronary disease (P = 0.043) as independent predictors of reduced CFR.
In patients without obstructive coronary disease, a higher FRS was an independent predictor of reduced CFR. The current study provides insight into the relation between cardiac risk profile and coronary microcirculatory function, and suggests that impaired microcirculatory vasodilator function may be present even in patients with a low to intermediate Framingham score.
Coronary atherosclerosis; Female; Framingham risk score; Endothelial function; Microcirculation
A 57-year-old man with a history of coronary artery disease and placement of an implantable cardioverter-defibrillator presented at our emergency room with an anterior ST-elevation myocardial infarction. Cardiac catheterization revealed an acutely occluded left main coronary artery, which was revascularized successfully with a bare-metal stent. Periprocedurally, the patient received aspirin, clopidogrel, unfractionated heparin, and eptifibatide.
The patient was discharged a week later, but he returned to the emergency room the same day with recurrence of severe chest pain. Repeat cardiac catheterization revealed an acutely occluded stent, and the patient underwent repeat bare-metal stent placement and readministration of eptifibatide. On the next day, the patient's platelet count dropped acutely to less than 12,000/mm3. A test for heparin-induced thrombocytopenia antibody was negative. After discontinuation of eptifibatide, the patient's platelet count gradually returned to normal, and he was later discharged from the hospital with no complications.
Eptifibatide-induced acute thrombocytopenia is a known but rare adverse effect. We review the handful of case reports in the medical literature, with emphasis on the prevalence, observed clinical course, and recently proposed physiologic mechanisms that probably are responsible for this phenomenon.
Acute coronary syndrome; antibodies, monoclonal/adverse effects; coronary stenosis/blood; eptifibatide; GPIIb/IIIa inhibitor; megakaryocytes; peptides/adverse effects; platelet aggregation inhibitors/therapeutic use; platelet glycoprotein GPIIb-IIIa complex/antagonists & inhibitors; ST-elevation myocardial infarction; stents; thrombocytopenia/chemically induced/etiology
To describe the proportion of “JUPITER-eligible” individuals and clinical outcomes of individuals based on high-sensitivity C-reactive protein (hs-CRP) and low-density lipoprotein cholesterol (LDL-C) strata in the Atherosclerosis Risk in Communities (ARIC) study.
Questions remain after the JUPITER study including whether the observed cardiovascular disease (CVD) event rates would persist with time and how these event rates would compare with other populations (lower hs-CRP and/or higher LDL-C levels).
After stratification into 4 groups based on LDL-C and hs-CRP levels, with cutoffs at 130 mg/dL and 2.0 mg/L, respectively incident CVD events were examined (mean follow-up 6.9 years) and compared.
Of 8,907 age-eligible participants, 18.2% (n=1,621) were “JUPITER-eligible” (hs-CRP ≥2.0 mg/L, LDL-C <130 mg/dL) and had an absolute CVD risk of ~10.9% over a mean follow-up of 6.9 years (1.57% per year). If JUPITER hazard ratios were applied to this group, the number needed to treat to prevent one CVD event would be estimated at 38 over 5 years and 26 over 6.9 years.
ARIC participants with elevated hs-CRP and low LDL-C had a CVD event rate of 1.57% per year over 6.9 years similar to the CVD event rate noted in the JUPITER study placebo group (1.36% per year over 1.9 years). The association of hs-CRP ≥2.0 mg/L with increased CVD risk and mortality regardless of LDL-C provides us a simple method of using age and hs-CRP for identifying higher risk individuals.
hs-CRP; LDL-C; ARIC; lipids; cardiovascular disease
The HOX11/TLX1 (hereafter referred to as HOX11) homeobox gene was originally identified at a t(10;14)(q24;q11) translocation breakpoint, a chromosomal abnormality observed in 5-7% of T cell acute lymphoblastic leukemias (T-ALLs). We previously reported a predisposition to aberrant spindle assembly checkpoint arrest and heightened incidences of chromosome missegregation in HOX11-overexpressing B lymphocytes following exposure to spindle poisons. The purpose of the current study was to evaluate cell cycle specific expression of HOX11.
Cell cycle specific expression studies revealed a phosphorylated form of HOX11 detectable only in the mitotic fraction of cells after treatment with inhibitors to arrest cells at different stages of the cell cycle. Mutational analyses revealed phosphorylation on threonine-247 (Thr247), a conserved amino acid that defines the HOX11 gene family and is integral for the association with DNA binding elements. The effect of HOX11 phosphorylation on its ability to modulate expression of the downstream target, cyclin B1, was tested. A HOX11 mutant in which Thr247 was substituted with glutamic acid (HOX11 T247E), thereby mimicking a constitutively phosphorylated HOX11 isoform, was unable to bind the cyclin B1 promoter or enhance levels of the cyclin B1 protein. Expression of the wildtype HOX11 was associated with accelerated progression through the G2/M phase of the cell cycle, impaired synchronization in prometaphase and reduced apoptosis whereas expression of the HOX11 T247E mutant restored cell cycle kinetics, the spindle checkpoint and apoptosis.
Our results demonstrate that the transcriptional activity of HOX11 is regulated by phosphorylation of Thr247 in a cell cycle-specific manner and that this phosphorylation modulates the expression of the target gene, cyclin B1. Since it is likely that Thr247 phosphorylation regulates DNA binding activity to multiple HOX11 target sequences, it is conceivable that phosphorylation functions to regulate the expression of HOX11 target genes involved in the control of the mitotic spindle checkpoint.
Disruption of lipid and carbohydrate homeostasis is an important factor in the development of prevalent metabolic diseases such as diabetes, obesity, and atherosclerosis. Therefore, small molecules that could reduce insulin dependence and regulate dyslipidemia could have a dramatic effect on public health. The grapefruit flavonoid naringenin has been shown to normalize lipids in diabetes and hypercholesterolemia, as well as inhibit the production of HCV. Here, we demonstrate that naringenin regulates the activity of nuclear receptors PPARα, PPARγ, and LXRα. We show it activates the ligand-binding domain of both PPARα and PPARγ, while inhibiting LXRα in GAL4-fusion reporters. Using TR-FRET, we show that naringenin is a partial agonist of LXRα, inhibiting its association with Trap220 co-activator in the presence of TO901317. In addition, naringenin induces the expression of PPARα co-activator, PGC1α. The flavonoid activates PPAR response element (PPRE) while suppressing LXRα response element (LXRE) in human hepatocytes, translating into the induction of PPAR-regulated fatty acid oxidation genes such as CYP4A11, ACOX, UCP1 and ApoAI, and inhibition of LXRα-regulated lipogenesis genes, such as FAS, ABCA1, ABCG1, and HMGR. This effect results in the induction of a fasted-like state in primary rat hepatocytes in which fatty acid oxidation increases, while cholesterol and bile acid production decreases. Our findings explain the myriad effects of naringenin and support its continued clinical development. Of note, this is the first description of a non-toxic, naturally occurring LXRα inhibitor.
Protease-activated receptor 1 (PAR1) is a G protein-coupled receptor that is not expressed in normal breast epithelia, but is up-regulated in invasive breast carcinomas. In the present study, we found that matrix metalloprotease-1 (MMP-1) robustly activates the PAR1-Akt survival pathway in breast carcinoma cells. This process is blocked by a cell-penetrating lipopeptide ‘pepducin’, P1pal-7, which is a potent inhibitor of cell viability in breast carcinoma cells expressing PAR1. Both a MMP-1 inhibitor and P1pal-7 significantly promote apoptosis in breast tumor xenografts and inhibit metastasis to the lungs by up to 88%. Dual therapy with P1pal-7 and taxotere inhibits the growth of MDA-MB-231 xenografts by 95%. Consistently, biochemical analysis of xenograft tumors treated with P1pal-7 or MMP-1 inhibitor demonstrated attenuated Akt activity. Ectopic expression of constitutively active Akt rescues breast cancer cells from the synergistic cytotoxicity of P1pal-7 and taxotere, suggesting that Akt is a critical component of PAR1-dependent cancer cell viability. Together, these findings indicate that blockade of MMP1-PAR1 signaling may provide a benefit beyond treatment with taxotere alone in advanced, metastatic breast cancer.
PAR1; MMP-1; Akt; pepducin; taxotere; breast cancer; metastasis
Epstein-Barr virus (EBV) is the prototypical example for episomal persistence of genetic information. Yet, little is known about how this viral episome is lost. Episome loss occurs naturally in naso-pharyngeal carcinoma (NPC) upon explantation into culture. Using whole-genome profiling, we found evidence for 2 different pathways of episome loss: (i) rapid loss of the entire episome or (ii) successive mutation/deletion of the episome until at least 1 essential cis-element is destroyed. This second phenotype was seen in a clone of HONE-1 NPC cells that maintains the EBV episome for prolonged time in culture. The conceptual insights provided by our quantitative analysis should aid our understanding of mammalian episomes, as well as lead to designs to cure latent viral infection.
episome; real-time QPCR; Epstein-Barr virus; naso-pharyngeal carcinoma; epithelial cells
Studies suggest that stress can be a co-factor for the initiation and progression of cancer. The catecholamine stress hormone, norepinephrine (NE), may influence tumor progression by modulating the expression of factors implicated in angiogenesis and metastasis. The goal of this study was to examine the influence of NE on the expression of VEGF, IL-8, and IL-6 by the human melanoma cell lines, C8161, 1174MEL, and Me18105. Cells were treated with NE and levels of VEGF, IL-8, and IL-6 were measured using ELISA and real-time PCR. The expression of β-adrenergic receptors (β-ARs) mRNA and protein were also assessed. Finally, immunohistochemitry was utilized to examine the presence of β1- and β2-AR in primary and metastatic human melanoma biopsies. We show that NE treatment upregulated production of VEGF, IL-8, and IL-6 in C8161 cells and to a lesser extent 1174MEL and Me18105 cells. The upregulation was associated with induced gene expression. The effect on C8161 cells was mediated by both β1- and β2-ARs. Furthermore, 18 of 20 melanoma biopsies examined expressed β2-AR while 14 of 20 melanoma biopsies expressed β1-AR. Our data support the hypothesis that NE can stimulate the aggressive potential of melanoma tumor cells, in part, by inducing the production VEGF, IL-8, and IL-6. This line of research further suggests that interventions targeting components of the activated sympathetic-adrenal medullary (SAM) axis, or the utilization of β-AR blocking agents, may represent new strategies for slowing down the progression of malignant disease and improving cancer patients’ quality of life.
psychological stress; norepinephrine; melanoma; cytokines; angiogenesis; vascular endothelial growth factor; interleukin (IL)-8; IL-6
One of the challenges in exploiting high throughput measurement techniques such as microarrays is the conversion of the vast amounts of data obtained into relevant knowledge. Of particular importance is the identification of the intrinsic response of a transcriptional experiment and the characterization of the underlying dynamics.
Methodology and Findings
The proposed algorithm seeks to provide the researcher a summary as to various aspects relating to the dynamic progression of a biological system, rather than that of individual genes. The approach is based on the identification of smaller number of expression motifs that define the transcriptional state of the system which quantifies the deviation of the cellular response from a control state in the presence of an external perturbation. The approach is demonstrated with a number of data sets including a synthetic base case and four animal studies. The synthetic dataset will be used to establish the response of the algorithm on a “null” dataset, whereas the four different experimental datasets represent a spectrum of possible time course experiments in terms of the degree of perturbation associated with the experiment as well as representing a wide range of temporal sampling strategies. This wide range of experimental datasets will thus allow us to explore the performance of the proposed algorithm and determine its ability identify relevant information.
Conclusions and Significance
In this work, we present a computational approach which operates on high throughput temporal gene expression data to assess the information content of the experiment, identify dynamic markers of important processes associated with the experimental perturbation, and summarize in a concise manner the evolution of the system over time with respect to the experimental perturbation.
Evidence from human and animal studies support the hypothesis that psychological stress can be a co-factor for the initiation and progression of cancer. Recent work from our laboratory and others have shown that the catecholamine hormone, norepinephrine (NE), may influence tumor progression of some solid epithelial tumors including nasopharyngeal carcinoma (NPC) and ovarian cancer by modulating the expression of proangiogenic and pro-metastatic factors, such as vascular endothelial growth factor (VEGF). In this study, we determined whether NE can likewise modulate the expression of VEGF in a lymphoid tumor, multiple myeloma (MM), a cancer of plasma cells. Three MM-derived cell lines, NIH-H929, MM-M1, and FLAM-76, were studied. The presence of β1- and β2-adrenergic receptors (ARs) was assessed using Western blotting. Cells were treated with 0, 1, and 10 μM NE for 1, 3, 6, and 24 hours and the levels of VEGF in culture supernatants were measured by ELISA. Immunoblots of cell lysates revealed the presence of β1- and β2-ARs in all three MM-derived cell lines. However, these MM-derived cell lines exhibited varying degrees of NE-dependent regulation of VEGF expression with FLAM-76 (the only IL-6-dependent cell line among the three) exhibiting the most significant stimulation, followed by MM-M1 cells and then NIH-H929. The data suggest that the ability of NE to regulate the expression of VEGF is not limited to solid epithelial tumors and suggests a possible regulatory role of catecholamine stress hormones in MM progression.
vascular endothelial growth factor; multiple myeloma; angiogenesis; norepinephrine; psychological stress