Cancer dormancy. VII. A regulatory role for CD8+ T cells and IFN-gamma in establishing and maintaining the tumor-dormant state

Dormant tumor cells resistant to ablative cancer therapy represent a significant clinical obstacle due to later relapse. Experimentally, the murine B cell lymphoma (BCL1) is used as a model of tumor dormancy in mice vaccinated with the BCL1 Ig. Here, we used this model to explore the cellular mechanisms underlying dormancy. Our previous studies have demonstrated that T cell-mediated immunity is an important component in the regulation of tumor dormancy because Id-immune T cells adoptively transferred into passively immunized SCID mice challenged with BCL1 cells significantly increased the incidence and duration of the dormant state. We have extended these observations and demonstrate that CD8+, but not CD4+, T cells are required for the maintenance of dormancy in BCL1 Ig-immunized BALB/c mice. In parallel studies, the transfer of Id-immune CD8+ cells, but not Id-immune CD4+ cells, conferred significant protection to SCID mice passively immunized with nonprotective levels of polyclonal anti-Id and then challenged with BCL1 cells. Furthermore, the ability of CD8+ T cells to induce a state of dormancy in passively immunized SCID mice was completely abrogated by treatment with neutralizing alpha-IFN-gamma mAbs in vivo. In vitro studies demonstrated that IFN-gamma alone or in combination with reagents to cross-link the surface Ig induced both cell cycle arrest and apoptosis in a BCL1 cell line. Collectively, these data demonstrate a role for CD8+ T cells via endogenous production of IFN-gamma in collaboration with humoral immunity to both induce and maintain a state of tumor dormancy.     

Excess portal venous long-chain fatty acids induce syndrome X via HPA axis and sympathetic activation

We tested the hypothesis that excessive portal venous supply of long-chain fatty acids to the liver contributes to the development of insulin resistance via activation of the hypothalamus-pituitary-adrenal axis (HPA axis) and sympathetic system. Rats received an intraportal infusion of the long-chain fatty acid oleate (150 nmol/min, 24 h), the medium-chain fatty acid caprylate, or the solvent. Corticosterone (Cort) and norepinephrine (NE) were measured as indexes for HPA axis and sympathetic activity, respectively. Insulin sensitivity was assessed by means of an intravenous glucose tolerance test (IVGTT). Oleate infusion induced increases in plasma Cort (Delta = 13.5 +/- 3.6 microg/dl; P < 0.05) and NE (Delta = 235 +/- 76 ng/l; P < 0.05), whereas caprylate and solvent had no effect. The area under the insulin response curve to the IVGTT was larger in the oleate-treated group than in the caprylate and solvent groups (area = 220 +/- 35 vs. 112 +/- 13 and 106 +/- 8, respectively, P < 0.05). The area under the glucose response curves was comparable [area = 121 +/- 13 (oleate) vs. 135 +/- 20 (caprylate) and 96 +/- 11 (solvent)]. The results are consistent with the concept that increased portal free fatty acid is involved in the induction of visceral obesity-related insulin resistance via activation of the HPA axis and sympathetic system.     

Association of common variation in the <Emphasis Type="Italic">PPARA</Emphasis>gene with incident myocardial infarction in individuals with type 2 diabetes: A Go-DARTS study

Background

Common variants of the PPARA gene have been found to associate with ischaemic heart disease in non diabetic men. The L162V variant was found to be protective while the C2528G variant increased risk. L162V has also been associated with altered lipid measures. We therefore sought to determine the effect of PPARA gene variation on susceptibility to myocardial infarction in patients with type 2 diabetes. 1810 subjects with type 2 diabetes from the prospective Go-DARTS study were genotyped for the L162V and C2528G variants in the PPARA gene and the association of the variants with incident non-fatal myocardial infarction was examined. Cox's proportional hazards was used to interrogate time to event from recruitment, and linear regression for analysing association of genotype with quantitative clinical traits.

Results

The V162 allele was associated with decreased risk of non-fatal myocardial infarction (HR = 0.31, 95%CI 0.10–0.93 p = 0.037) whereas the C2528 allele was associated with increased risk (HR = 2.77 95%CI 1.34–5.75 p = 0.006). Similarly V162 was associated with a later mean age of diagnosis with type 2 diabetes and C2582 an earlier age of diagnosis. C2528 was also associated with increased total cholesterol and LDL cholesterol, which did not account for the observed increased risk. Haplotype analysis demonstrated that when both rare variants occurred on the same haplotype the effect of each was abrogated.

Conclusion

Genetic variation at the PPARA locus is important in determining cardiovascular risk in both male and female patients with diabetes. This genotype associated risk appears to be independent of the effect of these genotypes on lipid profiles and age of diagnosis with diabetes.

     

Development and standardization of multiplexed antibody microarrays for use in quantitative proteomics

BACKGROUND: Quantitative proteomics is an emerging field that encompasses multiplexed measurement of many known proteins in groups of experimental samples in order to identify differences between groups. Antibody arrays are a novel technology that is increasingly being used for quantitative proteomics studies due to highly multiplexed content, scalability, matrix flexibility and economy of sample consumption. Key applications of antibody arrays in quantitative proteomics studies are identification of novel diagnostic assays, biomarker discovery in trials of new drugs, and validation of qualitative proteomics discoveries. These applications require performance benchmarking, standardization and specification. RESULTS: Six dual-antibody, sandwich immunoassay arrays that measure 170 serum or plasma proteins were developed and experimental procedures refined in more than thirty quantitative proteomics studies. This report provides detailed information and specification for manufacture, qualification, assay automation, performance, assay validation and data processing for antibody arrays in large scale quantitative proteomics studies. CONCLUSION: The present report describes development of first generation standards for antibody arrays in quantitative proteomics. Specifically, it describes the requirements of a comprehensive validation program to identify and minimize antibody cross reaction under highly multiplexed conditions; provides the rationale for the application of standardized statistical approaches to manage the data output of highly replicated assays; defines design requirements for controls to normalize sample replicate measurements; emphasizes the importance of stringent quality control testing of reagents and antibody microarrays; recommends the use of real-time monitors to evaluate sensitivity, dynamic range and platform precision; and presents survey procedures to reveal the significance of biomarker findings.     

Fetal microchimerism in kidney biopsies of lupus nephritis patients may be associated with a beneficial effect

IntroductionMicrochimeric male fetal cells (MFCs) have been associated with systemic lupus erythematosus, and published studies have further correlated MFC with lupus nephritis (LN). In the present study, we evaluated the frequency of MFC in the renal tissue of patients with LN.MethodsTwenty-seven renal biopsies were evaluated: Fourteen were from women with clinical and laboratory findings of LN, and thirteen were from controls. Genomic DNA was extracted from kidney biopsies, and the male fetal DNA was quantified using real-time quantitative polymerase chain reactions for the detection of specific Y chromosome sequences.ResultsMFCs were detected in 9 (64%) of 14 of patients with LN, whereas no MFCs were found in the control group (P = 0.0006). No differences in pregnancy history were found between patients with LN and the control group. Significantly higher amounts of MFCs were found in patients with LN with serum creatinine ≤1.5 mg/dl. Furthermore, women with MFCs had significantly better renal function at the time of biopsy (P = 0.03). In contrast, patients with LN without MFCs presented with more severe forms of glomerulonephritis (World Health Organization class IV = 60% and class V = 40%).ConclusionsOur data indicate a high prevalence of MFCs in renal biopsy specimens from women with LN, suggesting a role for MFCs in the etiology of LN. The present report also provides some evidence that MFCs could have a beneficial effect in this disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0615-4) contains supplementary material, which is available to authorized users.     

Undernutrition during pregnancy in mice leads to dysfunctional cardiac muscle respiration in adult offspring

Intrauterine growth restriction (IUGR) is associated with an increased risk of developing obesity, insulin resistance and cardiovascular disease. However, its effect on energetics in heart remains unknown. In the present study, we examined respiration in cardiac muscle and liver from adult mice that were undernourished in utero. We report that in utero undernutrition is associated with impaired cardiac muscle energetics, including decreased fatty acid oxidative capacity, decreased maximum oxidative phosphorylation rate and decreased proton leak respiration. No differences in oxidative characteristics were detected in liver. We also measured plasma acylcarnitine levels and found that short-chain acylcarnitines are increased with in utero undernutrition. Results reveal the negative impact of suboptimal maternal nutrition on adult offspring cardiac energy metabolism, which may have life-long implications for cardiovascular function and disease risk.     

Altered Sea Ice Thickness and Permanence Affects Benthic Ecosystem Functioning in Coastal Antarctica

Antarctic sea ice and the cold waters surrounding the continent are key elements of the global climate system, influencing heat redistribution, oceanic circulation and the absorption of carbon dioxide from the atmosphere. However, the Southern Ocean is predicted to warm by 1–6°C over the next century, altering sea ice extent, thickness and permanence. To better understand the connections between coastal sea ice conditions and the functioning of Antarctica’s unique marine benthic ecosystems, we performed manipulative experiments on the seafloor at two southwestern Ross Sea sites with contrasting sea ice conditions. Benthic systems at both study sites were net heterotrophic during the study period (early November), with primary production most likely limited by light availability rather than nutrients. There was five times more fresh algal detrital material in benthic sediments at the site with the thinner, snow-free, annually formed sea ice, relative to the site with thicker, multiyear sea ice. This elevated quantity and quality of algal detrital matter corresponded with a significantly greater rate of sediment oxygen utilization by the benthos and an altered pathway of nitrogen regeneration (tighter coupling between nitrification and denitrification). Large benthic animals (brittle stars, Ophionotus victoriae) enhanced the efflux of dissolved inorganic nutrients from the sediment to the water column and played a greater role in nutrient regeneration at the site with more food. Although changes in sea ice characteristics in the Western Ross Sea are difficult to predict at present, large benthic organisms can be expected to have an expanded role in mediating the effects of elevated coastal productivity and detritus supply on ecosystem dynamics in this part of Antarctica.     

Sensitivity of Heterogeneous Marine Benthic Habitats to Subtle Stressors

It is important to understand the consequences of low level disturbances on the functioning of ecological communities because of the pervasiveness and frequency of this type of environmental change. In this study we investigated the response of a heterogeneous, subtidal, soft-sediment habitat to small experimental additions of organic matter and calcium carbonate to examine the sensitivity of benthic ecosystem functioning to changes in sediment characteristics that relate to the environmental threats of coastal eutrophication and ocean acidification. Our results documented significant changes between key biogeochemical and sedimentary variables such as gross primary production, ammonium uptake and dissolved reactive phosphorus flux following treatment additions. Moreover, the application of treatments affected relationships between macrofauna communities, sediment characteristics (e.g., chlorophyll a content) and biogeochemical processes (oxygen and nutrient fluxes). In this experiment organic matter and calcium carbonate showed persistent opposing effects on sedimentary processes, and we demonstrated that highly heterogeneous sediment habitats can be surprisingly sensitive to subtle perturbations. Our results have important biological implications in a world with relentless anthropogenic inputs of atmospheric CO₂ and nutrients in coastal waters.