Cigarette smoke metabolically promotes cancer,via autophagy and premature aging in the host stromal microenvironment

Cigarette smoke has been directly implicated in the disease pathogenesis of a plethora of different human cancer subtypes, including breast cancers. The prevailing view is that cigarette smoke acts as a mutagen and DNA damaging agent in normal epithelial cells, driving tumor initiation. However, its potential negative metabolic effects on the normal stromal microenvironment have been largely ignored. Here, we propose a new mechanism by which carcinogen-rich cigarette smoke may promote cancer growth, by metabolically “fertilizing” the host microenvironment. More specifically, we show that cigarette smoke exposure is indeed sufficient to drive the onset of the cancer-associated fibroblast phenotype via the induction of DNA damage, autophagy and mitophagy in the tumor stroma. In turn, cigarette smoke exposure induces premature aging and mitochondrial dysfunction in stromal fibroblasts, leading to the secretion of high-energy mitochondrial fuels, such as L-lactate and ketone bodies. Hence, cigarette smoke induces catabolism in the local microenvironment, directly fueling oxidative mitochondrial metabolism (OXPHOS) in neighboring epithelial cancer cells, actively promoting anabolic tumor growth. Remarkably, these autophagic-senescent fibroblasts increased breast cancer tumor growth in vivo by up to 4-fold. Importantly, we show that cigarette smoke-induced metabolic reprogramming of the fibroblastic stroma occurs independently of tumor neo-angiogenesis. We discuss the possible implications of our current findings for the prevention of aging-associated human diseases and, especially, common epithelial cancers, as we show that cigarette smoke can systemically accelerate aging in the host microenvironment. Finally, our current findings are consistent with the idea that cigarette smoke induces the “reverse Warburg effect,” thereby fueling “two-compartment tumor metabolism” and oxidative mitochondrial metabolism in epithelial cancer cells.     

NFκB regulates expression of Polo-like kinase 4

Activation of the NFκB signaling pathway allows the cell to respond to infection and stress and can affect many cellular processes. As a consequence, NFκB activity must be integrated with a wide variety of parallel signaling pathways. One mechanism through which NFκB can exert widespread effects is through controlling the expression of key regulatory kinases. Here we report that NFκB regulates the expression of genes required for centrosome duplication, and that Polo-like kinase 4 (PLK4) is a direct NFκB target gene. RNA interference, chromatin immunoprecipitation, and analysis of the PLK4 promoter in a luciferase reporter assay revealed that all NFκB subunits participate in its regulation. Moreover, we demonstrate that NFκB regulation of PLK4 expression is seen in multiple cell types. Significantly long-term deletion of the NFκB2 (p100/p52) subunit leads to defects in centrosome structure. This data reveals a new component of cell cycle regulation by NFκB and suggests a mechanism through which deregulated NFκB activity in cancer can lead to increased genomic instability and uncontrolled proliferation.     

Electron Microscopic,Genetic and Protein Expression Analyses of Helicobacter acinonychis Strains from a Bengal Tiger

Colonization by Helicobacter species is commonly noted in many mammals. These infections often remain unrecognized, but can cause severe health complications or more subtle host immune perturbations. The aim of this study was to isolate and characterize putative novel Helicobacter spp. from Bengal tigers in Thailand. Morphological investigation (Gram-staining and electron microscopy) and genetic studies (16SrRNA, 23SrRNA, flagellin, urease and prophage gene analyses, RAPD DNA fingerprinting and restriction fragment polymorphisms) as well as Western blotting were used to characterize the isolated Helicobacters. Electron microscopy revealed spiral-shaped bacteria, which varied in length (2.5–6 µm) and contained up to four monopolar sheathed flagella. The 16SrRNA, 23SrRNA, sequencing and protein expression analyses identified novel H. acinonychis isolates closely related to H. pylori. These Asian isolates are genetically very similar to H. acinonychis strains of other big cats (cheetahs, lions, lion-tiger hybrid and other tigers) from North America and Europe, which is remarkable in the context of the great genetic diversity among worldwide H. pylori strains. We also found by immunoblotting that the Bengal tiger isolates express UreaseA/B, flagellin, BabA adhesin, neutrophil-activating protein NapA, HtrA protease, γ-glutamyl-transpeptidase GGT, Slt lytic transglycosylase and two DNA transfer relaxase orthologs that were known from H. pylori, but not the cag pathogenicity island, nor CagA, VacA, SabA, DupA or OipA proteins. These results give fresh insights into H. acinonychis genetics and the expression of potential pathogenicity-associated factors and their possible pathophysiological relevance in related gastric infections.     

Two Homologous EF-G Proteins from Pseudomonas aeruginosa Exhibit Distinct Functions

Genes encoding two proteins corresponding to elongation factor G (EF-G) were cloned from Pseudomonas aeruginosa. The proteins encoded by these genes are both members of the EFG I subfamily. The gene encoding one of the forms of EF-G is located in the str operon and the resulting protein is referred to as EF-G1A while the gene encoding the other form of EF-G is located in another part of the genome and the resulting protein is referred to as EF-G1B. These proteins were expressed and purified to 98% homogeneity. Sequence analysis indicated the two proteins are 90/84% similar/identical. In other organisms containing multiple forms of EF-G a lower degree of similarity is seen. When assayed in a poly(U)-directed poly-phenylalanine translation system, EF-G1B was 75-fold more active than EF-G1A. EF-G1A pre-incubate with ribosomes in the presence of the ribosome recycling factor (RRF) decreased polymerization of poly-phenylalanine upon addition of EF-G1B in poly(U)-directed translation suggesting a role for EF-G1A in uncoupling of the ribosome into its constituent subunits. Both forms of P. aeruginosa EF-G were active in ribosome dependent GTPase activity. The kinetic parameters (K _M) for the interaction of EF-G1A and EF-G1B with GTP were 85 and 70 μM, respectively. However, EF-G1B exhibited a 5-fold greater turnover number (observed k _cat) for the hydrolysis of GTP than EF-G1A; 0.2 s^-1 vs. 0.04 s^-1. These values resulted in specificity constants (k _cat ^obs/K _M) for EF-G1A and EF-G1B of 0.5 x 10³ s^-1 M^-1 and 3.0 x 10³ s^-1 M^-1, respectively. The antibiotic fusidic acid (FA) completely inhibited poly(U)-dependent protein synthesis containing P. aeruginosa EF-G1B, but the same protein synthesis system containing EF-G1A was not affected. Likewise, the activity of EF-G1B in ribosome dependent GTPase assays was completely inhibited by FA, while the activity of EF-G1A was not affected.     

Eligibility for Isoniazid Preventive Therapy in South African Gold Mines

Setting

The “Thibela TB” cluster randomised trial of community-wide isoniazid preventive therapy (IPT) to reduce tuberculosis incidence in the South African gold mines.

Objectives

To determine the proportion of participants eligible for IPT and the reasons and risk factors for ineligibility, to inform the scale-up of IPT.

Design

Cross-sectional survey of participants in intervention clusters (mine shafts) consenting to tuberculosis screening and assessment for eligibility to start IPT.

Results

Among 27,126 consenting participants, 94.7% were male, the median age was 41 years, 12.2% reported previous tuberculosis, 0.6% reported ever taking IPT and 2.5% reported currently taking antiretroviral therapy. There were 24,430 (90.1%) assessed as eligible to start IPT, of whom 23,659 started IPT. The most common reasons for ineligibility were having suspected tuberculosis that was subsequently confirmed by a positive smear and/or culture (n=705), excessive alcohol consumption (n=427) and being on tuberculosis treatment at time of initial screen (n=241). Ineligibility was associated with factors including older age, female gender, prior history of tuberculosis and being in “HIV care”. However, at least 78% were eligible for IPT in all of these sub-groups.

Conclusions

The vast majority of participants in this community-wide intervention were eligible for IPT.     

The Emergence of Urban Land Use Patterns Driven by Dispersion and Aggregation Mechanisms

We employ a cellular-automata to reconstruct the land use patterns of cities that we characterize by two measures of spatial heterogeneity: (a) a variant of spatial entropy, which measures the spread of residential, business, and industrial activity sectors, and (b) an index of dissimilarity, which quantifies the degree of spatial mixing of these land use activity parcels. A minimalist and bottom-up approach is adopted that utilizes a limited set of three parameters which represent the forces which determine the extent to which each of these sectors spatially aggregate into clusters. The dispersion degrees of the land uses are governed by a fixed pre-specified power-law distribution based on empirical observations in other cities. Our method is then used to reconstruct land use patterns for the city state of Singapore and a selection of North American cities. We demonstrate the emergence of land use patterns that exhibit comparable visual features to the actual city maps defining our case studies whilst sharing similar spatial characteristics. Our work provides a complementary approach to other measures of urban spatial structure that differentiate cities by their land use patterns resulting from bottom-up dispersion and aggregation processes.     

Profiles of Serum Cytokines in Acute Drug-Induced Liver Injury and Their Prognostic Significance

Drug-induced liver injury (DILI) is the most common cause of acute liver failure in the United-States. The aim of the study was to describe serum immune profiles associated with acute DILI, to investigate whether there are profiles associated with clinical features or types of DILI and/or with prognosis, and to assess temporal changes in levels. Twenty-seven immune analytes were measured in the sera of 78 DILI subjects in the Drug-Induced Liver Injury Network (DILIN) and compared with 40 healthy controls. Immune analytes (14 cytokines, 7 chemokines and 6 growth factors) were measured by BioPlex multiplex ELISA at DILI onset and after 6 months. A modeling process utilizing immune principles was used to select a final set of variables among 27 immune analytes and several additional clinical lab values for prediction of early death (within 6 months of DILI onset). Nineteen of the 27 immune analytes were differentially expressed among healthy control, DILI onset and 6-month cohorts. Disparate patterns of immune responses, especially innate and adaptive cellular (mostly TH17) immunity were evident. Low values of four immune analytes (IL-9, IL-17, PDGF-bb and RANTES) and serum albumin are predictive of early death [PPV = 88% (95% CI, 65%-100%), NPV = 97% (95% CI, 93%-100%), accuracy = 96% (95% CI, 92%-100%)].

Conclusions

Acute DILI is associated with robust and varying immune responses. High levels of expression of cytokines associated with innate immunity are associated with a poor prognosis, whereas high levels of expression of adaptive cytokines are associated with good long-term prognosis and eventual recovery. Serum immune analyte profiles at DILI onset appear to be of prognostic, and perhaps, diagnostic significance.