Interferon-inducible protein-10 identified as a mediator of tumor necrosis in vivo

Human Burkitt lymphoma cell lines give rise to progressively growing subcutaneous tumors in athymic mice. These tumors are induced to regress by inoculation of Epstein–Barr virus-immortalized normal human lymphocytes. In the present study, analysis of profiles of murine cytokine/chemokine gene expression in Burkitt tumor tissues excised from the nude mice showed that expression of the murine α-chemokine interferon-inducible protein-10 (IP-10) was higher in the regressing than in the progressive Burkitt tumors. We tested the effects of IP-10 on Burkitt tumor growth in nude mice. Inoculation of established Burkitt tumors either with crude preparations of murine IP-10 or with purified human IP-10 caused visible tumor necrosis in a proportion of the animals, although no complete tumor regressions were observed. Constitutive expression of murine IP-10 in Burkitt cells reduced their ability to grow as subcutaneous tumors, and caused visible tumor necrosis in a proportion of the animals. Histologically, IP-10-treated and IP-10-expressing Burkitt tumors had widespread evidence of tumor tissue necrosis and of capillary damage, including intimal thickening and vascular thrombosis. Thus, IP-10 is an antitumor agent that promotes damage in established tumor vasculature and causes tissue necrosis in human Burkitt lymphomas established subcutaneously in athymic mice.     

Antibody production by single, hapten-specific B lymphocytes: an antigen-driven cloning system free of filler or accessory cells.

CBA mouse spleen cells were subjected to hapten affinity fractionation on thin layers of fluorescein (FLU)-gelatin. This procedure yields 97% B cells with varying FLU-binding avidities. One to 30 cells were placed in 10-microliter microcultures without any filler or accessory cells. the T-independent antigen polymerized flagellin coupled to FLU (FLU-POL) was ineffective in stimulating these cells to clonal proliferation or antibody production when used alone. Unpurified preparations rich in interleukins also failed to stimulate the cells. When specific antigen, but not in irrelevant hapten-POL, was combined with the interleukins, clonal proliferation was stimulated and most clones produced anti-FLU antibody-forming cells. The frequency of antibody-forming clones was only slightly lower than that in a system using antigen plus filler cells. In the absence of added interleukins, the mitogens Escherichia coli lipopolysaccharide plus dextran sulfate induced equivalent antibody production. However, a higher frequency of clonal proliferation was noted. Added interleukins did not aid these mitogen-driven responses. Such an antigen-dependent cloning system, free of filler and accessory cells, should permit more precise analysis of the respective roles of antigens and interleukins in the physiology of antibody-forming clone formation.     

Post-translational polymodification of b1-tubulin regulates motor protein localization in platelet production and function

In specialized cells, the expression of specific tubulin isoforms and their subsequent post-translational modifications drive and coordinate unique morphologies and behaviors. The mechanisms by which b1-tubulin, the platelet and megakaryocyte (MK) lineage restricted tubulin isoform, drives platelet production and function remains poorly understood. We investigated the roles of two key post-translational tubulin polymodifications (polyglutamylation and polyglycylation) on these processes using a cohort of thrombocytopenic patients, human induced pluripotent stem cell derived MK, and healthy human donor platelets. We find distinct patterns of polymodification in MK and platelets, mediated by the antagonistic activities of the cell specific expression of tubulin tyrosine ligase like enzymes and cytosolic carboxypeptidase enzymes. The resulting microtubule patterning spatially regulates motor proteins to drive proplatelet formation in megakaryocytes, and the cytoskeletal reorganization required for thrombus formation. This work is the first to show a reversible system of polymodification by which different cell specific functions are achieved.     

Interval breast cancer risk associations with breast density,family history and breast tissue aging

Interval breast cancers (those diagnosed between recommended mammography screens) generally have poorer outcomes and are more common among women with dense breasts. We aimed to develop a risk model for interval breast cancer. We conducted a nested case–control study within the Melbourne Collaborative Cohort Study involving 168 interval breast cancer patients and 498 matched control subjects. We measured breast density using the CUMULUS software. We recorded first-degree family history by questionnaire, measured body mass index (BMI) and calculated age-adjusted breast tissue aging, a novel measure of exposure to estrogen and progesterone based on the Pike model. We fitted conditional logistic regression to estimate odds ratio (OR) or odds ratio per adjusted standard deviation (OPERA) and calculated the area under the receiver operating characteristic curve (AUC). The stronger risk associations were for unadjusted percent breast density (OPERA = 1.99; AUC = 0.66), more so after adjusting for age and BMI (OPERA = 2.26; AUC = 0.70), and for family history (OR = 2.70; AUC = 0.56). When the latter two factors and their multiplicative interactions with age-adjusted breast tissue aging (p = 0.01 and 0.02, respectively) were fitted, the AUC was 0.73 (95% CI 0.69–0.77), equivalent to a ninefold interquartile risk ratio. In summary, compared with using dense breasts alone, risk discrimination for interval breast cancers could be doubled by instead using breast density, BMI, family history and hormonal exposure. This would also give women with dense breasts, and their physicians, more information about the major consequence of having dense breasts—an increased risk of developing an interval breast cancer.     

Improvement in Cardiovascular Risk Prediction with Electronic Health Records

The aim of this study was to compare the QRISKII, an electronic health data-based risk score, to the Framingham Risk Score (FRS) and atherosclerotic cardiovascular disease (ASCVD) score. Risk estimates were calculated for a cohort of 8783 patients, and the patients were followed up from November 29, 2012, through June 1, 2015, for a cardiovascular disease (CVD) event. During follow-up, 246 men and 247 women had a CVD event. Cohen’s kappa statistic for the comparison of the QRISKII and FRS was 0.22 for men and 0.23 for women, with the QRISKII classifying more patients in the higher-risk groups. The QRISKII and ASCVD were more similar with kappa statistics of 0.49 for men and 0.51 for women. The QRISKII shows increased discrimination with area under the curve (AUC) statistics of 0.65 and 0.71, respectively, compared to the FRS (0.59 and 0.66) and ASCVD (0.63 and 0.69). These results demonstrate that incorporating additional data from the electronic health record (EHR) may improve CVD risk stratification.     

A genetic polymorphism for translocator protein 18?kDa affects both in vitro and in vivo radioligand binding in human brain to this putative biomarker of neuroinflammation

Second-generation radioligands for translocator protein (TSPO), an inflammation marker, are confounded by the codominant rs6971 polymorphism that affects binding affinity. The resulting three groups are homozygous for high-affinity state (HH), homozygous for low-affinity state (LL), or heterozygous (HL). We tested if in vitro binding to leukocytes distinguished TSPO genotypes and if genotype could affect clinical studies using the TSPO radioligand [¹¹C]PBR28. In vitro binding to leukocytes and [¹¹C]PBR28 brain imaging were performed in 27 human subjects with known TSPO genotype. Specific [³H]PBR28 binding was measured in prefrontal cortex of 45 schizophrenia patients and 47 controls. Leukocyte binding to PBR28 predicted genotype in all subjects. Brain uptake was ∼40% higher in HH than HL subjects. Specific [³H]PBR28 binding in LL controls was negligible, while HH controls had ∼80% higher binding than HL controls. After excluding LL subjects, specific binding was 16% greater in schizophrenia patients than controls. This difference was insignificant by itself (P=0.085), but was significant after correcting for TSPO genotype (P=0.011). Our results show that TSPO genotype influences PBR28 binding in vitro and in vivo. Correcting for this genotype increased statistical power in our postmortem study and is recommended for in vivo positron emission tomography studies.