The role of neutrophil myeloperoxidase in models of lung tumor development

Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting

The Role of Neutrophil Myeloperoxidase in Models of Lung Tumor Development

Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting

The SPOROCYTELESS/NOZZLE Gene Is Involved in Controlling Stamen Identity in Arabidopsis1[W][OA]

The stamen, which consists of an anther and a filament, is the male reproductive organ in a flower. The specification of stamen identity in Arabidopsis (Arabidopsis thaliana) is controlled by a combination of the B genes APETALA3 (AP3) and PISTILLATA, the C gene AGAMOUS (AG), and the E genes SEPALLATA1 (SEP1) to SEP4. The “floral organ-building” gene SPOROCYTELESS/NOZZLE (SPL/NZZ) plays a central role in regulating anther cell differentiation. However, much less is known about how “floral organ identity” and floral organ-building genes interact to control floral organ development. In this study, we report that ectopic expression of SPL/NZZ not only affects flower development in the wild-type background but also leads to the transformation of petal-like organs into stamen-like organs in flowers of ap2-1, a weak ap2 mutant allele. Moreover, our loss-of-function analysis indicates that the spl/nzz mutant enhances the phenotype of the ag weak allele ag-4. Furthermore, ectopic expression and overexpression of SPL/NZZ altered expression of AG, SEP3, and AP2 in rosette leaves and flowers, while ectopic expression of SPL/NZZ resulted in ectopic expression of AG and SEP3 in the outer whorls of flowers. Our results indicate that the SPL/NZZ gene is engaged in controlling stamen identity via interacting with genes required for stamen identity in Arabidopsis

Inter-Individual Differences in RNA Levels in Human Peripheral Blood

<div><p>Relatively little is known about the range of RNA levels in human blood. This report provides assessment of peripheral blood RNA level and its inter-individual differences in a group of 35 healthy humans consisting of 25 females and 10 males ranging in age from 50 to 89 years. In this group, the average total RNA level was 14.59 μg/ml of blood, with no statistically significant difference between females and males. The individual RNA level ranged from 6.7 to 22.7 μg/ml of blood. In healthy subjects, the repeated sampling of an individual’s blood showed that RNA level, whether high or low, was stable. The inter-individual differences in RNA level in blood can be attributed to both, differences in cell number and the amount of RNA per cell. The 3.4-fold range of inter-individual differences in total RNA levels, documented herein, should be taken into account when evaluating the results of quantitative RT-PCR and/or RNA sequencing studies of human blood. Based on the presented results, a comprehensive assessment of gene expression in blood should involve determination of both the amount of mRNA per unit of total RNA (U / ng RNA) and the amount of mRNA per unit of blood (U / ml blood) to assure a thorough interpretation of physiological or pathological relevance of study results.</p></div

Characteristics of RNA isolated from healthy donors.

<p>a) Proportion of the large and small RNA fractions in relation to increasing quantities of total RNA in human peripheral blood. Samples of RNA from the 35 individuals are sequentially ranked in accord with the increasing amount of total RNA in the sample. For each sample, the amounts of the large RNA fraction (inverted triangle) and small RNA fraction (square) are depicted. b) The large RNA and small RNA fractions are expressed as a percentage of the total RNA in the sample. c) Bioanalyzer RIN values of the large RNA fractions from 35 samples.</p

Bioanalyzer profiles of the large RNA fractions isolated from donors with the lowest and highest blood RNA level.

<p>The large RNA fractions (200 ng) from the low RNA level sample 180 (6.7 μg RNA/ml blood) and the high RNA level sample 162 (22.7 μg RNA/ml blood) were separated using the Bioanalyzer RNA Nano 6000 Kit. Shown are positions of: the (18S) and (28S) ribosomal RNA; the 600 nt globin region (G); and Bioanalyzer marker (M).</p

The total RNA level in blood collected over a period of 30 to 270 days from female (F) and male (M) donors.

<p>Total RNA was extracted from six blood donors using RNAzol BD as described in the Methods section. The calculated within-individual coefficient of variation of blood RNA level for the six donors was 9.2, 4.8, 6.2, 1.1, 7.6 and 6.9, respectively.</p

Robust regression analysis of total RNA vs the product of blood DNA level (μg DNA / ml blood) and cellular RNA content (pg RNA/ cell).

<p>The blue dashed line represents the 95% prediction interval for the group of 35 samples. An adjusted R-square value for this regression analysis is 0.947.</p