97 research outputs found
Recognition and Acceptance: An Examination of the Louisiana Volunteer Battalions on Line Jackson
This paper examines the motivators and legacy of the Louisiana volunteer units on Line Jackson during the winter of 1814-1815. Orleans Parish fielded three volunteer battalions to the final engagements: the Orleans Volunteers, and the First and Second Battalions of Free Men of Color. Two companies, Beale’s Rifles and a Baratarian artillery unit, were attached to the Orleans Volunteers under the command of Major Plauché. Each volunteer, both as an individual and as a unit, hoped to gain some benefit from military service beyond defense of their homes. This paper argues that each one sought recognition and acceptance from their community and from the republic for which they fought. The experience of Louisiana’s Creoles under both French and Spanish regimes held that military service was necessary to attain economic and social advantage. The Battle of New Orleans tested whether or not military service under the American republic provided the same benefit
Recognition and Acceptance: An Examination of the Louisiana Volunteer Battalions on Line Jackson
This paper examines the motivators and legacy of the Louisiana volunteer units on Line Jackson during the winter of 1814-1815. Orleans Parish fielded three volunteer battalions to the final engagements: the Orleans Volunteers, and the First and Second Battalions of Free Men of Color. Two companies, Beale’s Rifles and a Baratarian artillery unit, were attached to the Orleans Volunteers under the command of Major Plauché. Each volunteer, both as an individual and as a unit, hoped to gain some benefit from military service beyond defense of their homes. This paper argues that each one sought recognition and acceptance from their community and from the republic for which they fought. The experience of Louisiana’s Creoles under both French and Spanish regimes held that military service was necessary to attain economic and social advantage. The Battle of New Orleans tested whether or not military service under the American republic provided the same benefit
Hepatitis C Virus Indirectly Disrupts DNA Damage-Induced p53 Responses by Activating Protein Kinase R
ABSTRACT Many DNA tumor viruses promote cellular transformation by inactivating the critically important tumor suppressor protein p53. In contrast, it is not known whether p53 function is disrupted by hepatitis C virus (HCV), a unique, oncogenic RNA virus that is the leading infectious cause of liver cancer in many regions of the world. Here we show that HCV-permissive, liver-derived HepG2 cells engineered to constitutively express microRNA-122 (HepG2/miR-122 cells) have normal p53-mediated responses to DNA damage and that HCV replication in these cells potently suppresses p53 responses to etoposide, an inducer of DNA damage, or nutlin-3, an inhibitor of p53 degradation pathways. Upregulation of p53-dependent targets is consequently repressed within HCV-infected cells, with potential consequences for cell survival. Despite this, p53 function is not disrupted by overexpression of the complete HCV polyprotein, suggesting that altered p53 function may result from the host response to viral RNA replication intermediates. Clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9-mediated ablation of double-stranded RNA (dsRNA)-activated protein kinase R (PKR) restored p53 responses while boosting HCV replication, showing that p53 inhibition results directly from viral activation of PKR. The hepatocellular abundance of phosphorylated PKR is elevated in HCV-infected chimpanzees, suggesting that PKR activation and consequent p53 inhibition accompany HCV infection in vivo . These findings reveal a feature of the host response to HCV infection that may contribute to hepatocellular carcinogenesis. IMPORTANCE Chronic infection with hepatitis C virus (HCV) is the leading cause of liver cancer in most developed nations. However, the mechanisms whereby HCV infection promotes carcinogenesis remain unclear. Here, we demonstrate that HCV infection inhibits the activation of p53 following DNA damage. Contrary to previous reports, HCV protein expression is insufficient to inhibit p53. Rather, p53 inhibition is mediated by cellular protein kinase R (PKR), which is activated by HCV RNA replication and subsequently suppresses global protein synthesis. These results redefine our understanding of how HCV infection influences p53 function. We speculate that persistent disruption of p53-mediated DNA damage responses may contribute to hepatocellular carcinogenesis in chronically infected individuals
Treg depletion potentiates checkpoint inhibition in claudin-low breast cancer
Claudin-low breast cancer is an aggressive subtype that confers poor prognosis and is found largely within the clinical triple-negative group of breast cancer patients. Here, we have shown that intrinsic and immune cell gene signatures distinguish the claudin-low subtype clinically as well as in mouse models of other breast cancer subtypes. Despite adaptive immune cell infiltration in claudin-low tumors, treatment with immune checkpoint inhibitory antibodies against cytotoxic T lymphocyte–associated protein 4 (CTLA-4) and programmed death receptor 1 (PD-1) were ineffective in controlling tumor growth. CD4+FoxP3+ Tregs represented a large proportion of the tumor-infiltrating lymphocytes (TILs) in claudin-low tumors, and Tregs isolated from tumor-bearing mice were able to suppress effector T cell responses. Tregs in the tumor microenvironment highly expressed PD-1 and were recruited partly through tumor generation of the chemokine CXCL12. Antitumor efficacy required stringent Treg depletion combined with checkpoint inhibition; delays in tumor growth were not observed using therapies that modestly diminished the number of Tregs in the tumor microenvironment. This study provides evidence that the recruitment of Tregs to the tumor microenvironment inhibits an effective antitumor immune response and highlights early Treg recruitment as a possible mechanism for the lack of response to immune checkpoint blockade antibodies in specific subtypes of cancer that are heavily infiltrated with adaptive immune cells
Development of DNA Damage Response Signaling Biomarkers using Automated, Quantitative Image Analysis
The DNA damage response (DDR) coordinates DNA repair with cell cycle checkpoints to ameliorate or mitigate the pathological effects of DNA damage. Automated quantitative analysis (AQUA) and Tissue Studio are commercial technologies that use digitized immunofluorescence microscopy images to quantify antigen expression in defined tissue compartments. Because DDR is commonly activated in cancer and may reflect genetic instability within the lesion, a method to quantify DDR in cancer offers potential diagnostic and/or prognostic value. In this study, both AQUA and Tissue Studio algorithms were used to quantify the DDR in radiation-damaged skin fibroblasts, melanoma cell lines, moles, and primary and metastatic melanomas. Digital image analysis results for three markers of DDR (γH2AX, P-ATM, P-Chk2) correlated with immunoblot data for irradiated fibroblasts, whereas only γH2AX and P-Chk2 correlated with immunoblot data in melanoma cell lines. Melanoma cell lines displayed substantial variation in γH2AX and P-Chk2 expression, and P-Chk2 expression was significantly correlated with radioresistance. Moles, primary melanomas, and melanoma metastases in brain, lung and liver displayed substantial variation in γH2AX expression, similar to that observed in melanoma cell lines. Automated digital analysis of immunofluorescent images stained for DDR biomarkers may be useful for predicting tumor response to radiation and chemotherapy
Examination and prognostic implications of the unique microenvironment of breast cancer brain metastases
Purpose: Brain metastases (BM) are a complication of advanced breast cancer (BC). Histology of melanoma BM offers prognostic value; however, understanding the microenvironment of breast cancer brain metastases (BCBM) is less characterized. This study reports on four histological biomarkers, gliosis, immune infiltrate, hemorrhage, necrosis, and their prognostic significance in BCBM. Methods: A biobank of 203 human tissues from patients who underwent craniotomy for BCBM was created across four academic institutions. Degree of gliosis, immune infiltrate, hemorrhage, and necrosis were identified and scored via representative H&E stain (0–3+). Overall survival (OS) was estimated using the Kaplan–Meier method. Cox proportional hazards regression evaluated prognostic value of the biomarkers in the context of standard clinical characteristics. Results: BCBM subtype (available for n = 158) was 36% Her2+, 26% hormone receptor (HR)+/Her2− 38% HR−/Her2− (triple negative, TN). Gliosis was observed in 82% (116/141) of BCBM, with immune infiltrate 44% (90/201), hemorrhage 82% (166/141), and necrosis 87% (176/201). Necrosis was significantly higher in TNBC (p < 0.01). Presence of gliosis, immune infiltrate, and hemorrhage correlated with improved OS (p = 0.03, p = 0.03, p = 0.1), while necrosis correlated with inferior OS (p = 0.01). Improved OS was associated with gliosis in TN (p = 0.02), and immune infiltrate (p = 0.001) and hemorrhage (p = 0.07) in HER2+. In a multivariable model for OS, incorporating these biomarkers with traditional clinical variables improved the model fit (p < 0.001). Conclusion: Gliosis confers superior prognosis in TNBC BM; immune infiltrate and hemorrhage correlate with superior prognosis in HER2+ BCBM. Understanding the metastatic microenvironment of BCBM refines prognostic considerations and may unveil novel therapeutic strategies
Effects of Tumor Microenvironment Heterogeneity on Nanoparticle Disposition and Efficacy in Breast Cancer Tumor Models
Tumor cells are surrounded by a complex microenvironment. The purpose of our study was to evaluate the role of heterogeneity of the tumor microenvironment in the variability of nanoparticle (NP) delivery and efficacy
Behavioral genetics and taste
This review focuses on behavioral genetic studies of sweet, umami, bitter and salt taste responses in mammals. Studies involving mouse inbred strain comparisons and genetic analyses, and their impact on elucidation of taste receptors and transduction mechanisms are discussed. Finally, the effect of genetic variation in taste responsiveness on complex traits such as drug intake is considered. Recent advances in development of genomic resources make behavioral genetics a powerful approach for understanding mechanisms of taste
MERTK receptor tyrosine kinase is a therapeutic target in melanoma
Metastatic melanoma is one of the most aggressive forms of cutaneous cancers. Although recent therapeutic advances have prolonged patient survival, the prognosis remains dismal. C-MER proto-oncogene tyrosine kinase (MERTK) is a receptor tyrosine kinase with oncogenic properties that is often overexpressed or activated in various malignancies. Using both protein immunohistochemistry and microarray analyses, we demonstrate that MERTK expression correlates with disease progression. MERTK expression was highest in metastatic melanomas, followed by primary melanomas, while the lowest expression was observed in nevi. Additionally, over half of melanoma cell lines overexpressed MERTK compared with normal human melanocytes; however, overexpression did not correlate with mutations in BRAF or RAS. Stimulation of melanoma cells with the MERTK ligand GAS6 resulted in the activation of several downstream signaling pathways including MAPK/ERK, PI3K/AKT, and JAK/STAT. MERTK inhibition via shRNA reduced MERTK-mediated downstream signaling, reduced colony formation by up to 59%, and diminished tumor volume by 60% in a human melanoma murine xenograft model. Treatment of melanoma cells with UNC1062, a novel MERTK-selective small-molecule tyrosine kinase inhibitor, reduced activation of MERTK-mediated downstream signaling, induced apoptosis in culture, reduced colony formation in soft agar, and inhibited invasion of melanoma cells. This work establishes MERTK as a therapeutic target in melanoma and provides a rationale for the continued development of MERTK-targeted therapies
ICEF2004-851 SENSITIVITY ANALYSIS OF NO X FORMATION IN MICRO-PILOT IGNITED NATURAL GAS ENGINES
ABSTRACT A sensitivity analysis of NO x formation in micro-pilot ignited natural gas dual fuel engines is performed based on a phenomenological combustion model. The model's NO x formation mechanism incorporates a super-extended Zel'dovich mechanism (up to 43 reactions). The sensitivity analysis compares the contribution of each major reaction to NO x formation, and identifies the rate controlling NO x formation reactions. The formation rates for reactions involving NO x are also investigated to reveal the primary NO x formation paths. Results show that there are two main NO x formation paths both in the packets zone and the burned zone Since the aforementioned reactions significantly influence the net NO x prediction, it is important that the corresponding reaction rates be determined fairly accurately. Finally, because the quasi-steady-state assumption is commonly used for certain species in NO x modeling, a transient relative error is estimated to evaluate its use. The relative error in NO x prediction with and without this assumption is of the order of 2 percent. Clearly, sensitivity analysis can provide valuable insight into understanding the possible NO x formation pathways in engines and improve the status of current prediction tools to obtain better estimates
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