Exome sequencing of gastric adenocarcinoma identifies recurrent somatic mutations in cell adhesion and chromatin remodelling genes

Gastric cancer is a major cause of global cancer mortality. We surveyed the spectrum of somatic alterations in gastric cancer by sequencing the exomes of 15 gastric adenocarcinomas and their matched normal DNAs. Frequently mutated genes in the adenocarcinomas included TP53 (11/15 tumors), PIK3CA (3/15) and ARID1A (3/15). Cell adhesion was the most enriched biological pathway among the frequently mutated genes. A prevalence screening confirmed mutations in FAT4, a cadherin family gene, in 5% of gastric cancers (6/110) and FAT4 genomic deletions in 4% (3/83) of gastric tumors. Frequent mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) also occurred in 47% of the gastric cancers. We detected ARID1A mutations in 8% of tumors (9/110), which were associated with concurrent PIK3CA mutations and microsatellite instability. In functional assays, we observed both FAT4 and ARID1A to exert tumor-suppressor activity. Somatic inactivation of FAT4 and ARID1A may thus be key tumorigenic events in a subset of gastric cancers.

Development of a novel experimental model to investigate radiobiological implications of respiratory motion in advanced radiotherapy

Respiratory motion introduces complex spatio-temporal variations in the dosimetry of radiotherapy. There is a paucity of literature investigating the radiobiological consequences of intrafraction motion and concerns regarding the impact of movement when applied to cancer cell lines in vitro exist. We have addressed this by developing a novel model which accurately replicates respiratory motion under experimental conditions to allow clinically relevant irradiation of cell lines. A bespoke phantom and motor driven moving platform was adapted to accommodate flasks containing medium and cells in order to replicate respiratory motion using varying frequencies and amplitude settings. To study this effect on cell survival in vitro, dose response curves were determined for human lung cancer cell lines H1299 and H460 exposed to a uniform 6 MV radiation field under moving or stationary conditions. Cell survival curves showed no significant difference between irradiation at different dose points for these cell lines in the presence or absence of motion. These data indicate that motion of unshielded cells in vitro does not affect cell survival in the presence of uniform irradiation. This model provides a novel research platform to investigate the radiobiological consequences of respiratory motion in radiotherapy.

Clinical cough II:therapeutic treatments and management of chronic cough

Chronic cough is a common and frequently disruptive symptom which can be difficult to treat with currently available medicines. Asthma/eosinophilic airway disease and gastro-oesophageal reflux disease are most commonly associated with chronic cough but it may also trouble patients with chronic obstructive pulmonary disease, pulmonary fibrosis and lung cancer. Over the last three decades there have been a number of key advances in the clinical approach to cough and a number of international guidelines on the management of cough have been developed. Despite the undoubted benefit of such initiatives, more effective treatments for cough are urgently needed. The precise pathophysiological mechanisms of chronic cough are unknown but central to the process is sensitization (upregulation) of the cough reflex. One well-recognized clinical consequence of this hypersensitive state is bouts of coughing triggered by apparently trivial provocation such as scents and odours and changes in air temperature. The main objective of new treatments for cough would be to identify ways to downregulate this heightened cough reflex but yet preserve its crucial role in protecting the airway. The combined efforts of clinicians, scientists and the pharmaceutical industry offer most hope for such a treatment breakthrough. The aim of this chapter is to provide some rationale for the current treatment recommendations and to offer some reflections on the management of patients with chronic cough.

PKB-mediated PHF20 phosphorylation on Ser291 is required for p53 function in DNA damage

PHD finger protein 20 (PHF20) is a transcription factor, which was originally identified in glioma patients. PHF20 appears to be a novel antigen in glioma, and has also termed glioma-expressed antigen 2. PHF20 is thought to contribute to the development of cancers, including glioblastoma, lung cancer, colon cancer and ovarian cancer. However, little is known about the function of PHF20 in various cancers. Here we report that PHF20 contains two consensus sites for protein kinase B (PKB) phosphorylation (RxRxxS/T). PKB can directly phosphorylate PHF20 on Ser291 in vitro and in vivo. It has been shown that PKB participates in the tumor suppressor p53 regulated gene expression program and has a direct effect on p21 regulation after DNA damage. UV-induced DNA damage results in accumulation of p53 and PKB activation. Interestingly, PKB-mediated PHF20 phosphorylation led to an inhibition of p53 induction following UV treatment, leading to the reduction of p21 transcriptional activity. Using anti PHF20 and anti pPKB (S473) antibodies, these events were mapped in various human cancer tissues. Taken together, these data suggest that PHF20 is a novel substrate for PKB and its phosphorylation by PKB plays an important role in tumorigenesis via regulating of p53 mediated signaling. © 2012 Elsevier Inc.

Impact of cigarette smoke exposure on host-bacterial pathogen interactions

The human respiratory tract of individuals with normal lung function maintains a fine-tuned balance, being asymptomatically colonised by the normal microbiota in the upper airways and sterile in the lower tract. This equilibrium may be disrupted by the exposure to insults such as cigarette smoke. In the respiratory tract, the complex and noxious nature of inhaled cigarette smoke alters host-microorganisminteraction dynamics at all anatomical levels, causing infections in many cases. Moreover, continuous exposure to cigarette smoke itself causes deleterious effects on the host that can trigger the development of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. COPD is an irreversible airflow obstruction associated with emphysema, fibrosis, mucus hypersecretion and persistent colonisation of the lower airways by opportunistic pathogens. COPD patients keep a stable (without exacerbation) but progressively worsening condition and suffer periodic exacerbations caused, in most cases, by infections. Although smoking and smoking-associated diseases are associated with a high risk of infection, most therapies aim to reduce inflammatory parameters, but do not necessarily take into account the presence of persistent colonisers. The effect of cigarette smoke on host-pathogen interaction dynamics in the respiratory tract, together with current and novel therapies, is discussed. Copyright©ERS 2012.

Achaete-scute homolog-1 linked to remodeling and preneoplasia of pulmonary epithelium

The basic helix-loop-helix protein achaete-scute homolog-1 (ASH1) is involved in lung neuroendocrine (NE) differentiation and tumor promotion in SV40 transgenic mice. Constitutive expression of human ASH-1 (hASH1) in mouse lung results in hyperplasia and remodeling that mimics bronchiolization of alveoli (BOA), a potentially premalignant lesion of human lung carcinomas. We now show that this is due to sustained cellular proliferation in terminal bronchioles and resistance to apoptosis. Throughout the airway epithelium the expression of anti-apoptotic Bcl-2 and c-Myb was increased and Akt/mTOR pathway activated. Moreover, the expression of matrix metalloproteases (MMPs) including MMP7 was specifically enhanced at the bronchiolo-alveolar duct junction and BOA suggesting that MMPs play a key role in this microenvironment during remodeling. We also detected MMP7 in 70% of human BOA lesions. Knockdown of hASH1 gene in human lung cancer cells in vitro suppressed growth by increasing apoptosis. We also show that forced expression of hASH1 in immortalized human bronchial epithelial cells decreases apoptosis. We conclude that the impact of hASH1 is not limited to cells with NE phenotype. Rather, constitutive expression of hASH1 in lung epithelium promotes remodeling through multiple pathways that are commonly activated during lung carcinogenesis. The collective results suggest a novel model of BOA formation via hASH1-induced suppression of the apoptotic pathway. Our study yields a promising new preclinical tool for chemoprevention of peripheral lung carcinomas. © 2007 USCAP, Inc All rights reserved.

Smoking is a major cause of premature death worldwide

Question. How many deaths were attributable to smoking in 2000 worldwide? Study design. Statistical extrapolation of epidemiological and clinical data. Main results. In the year 2000, about 12% of adults died prematurely from smoking (estimated 4.83 million uncertainty range 3.94-5.93 million). Leading causes of death attributable to smoking were cardiovascular diseases (1.69 million deaths), chronic obstructive pulmonary disease (0.97 million deaths) and lung cancer (0.85 million deaths; 71% of lung cancers were smoking related). Smoking related deaths in men were about 3 times more common than women in industrial countries, and about 7 times more common in developing countries. Authors' conclusions. Smoking was a major cause of death worldwide in 2000. © 2004 Elsevier Ltd. All rights reserved.

Investigating the influence of respiratory motion on the radiation induced bystander effect in modulated radiotherapy

Respiratory motion introduces complex spatio-temporal variations in the dosimetry of radiotherapy and may contribute towards uncertainties in radiotherapy planning. This study investigates the potential radiobiological implications occurring due to tumour motion in areas of geometric miss in lung cancer radiotherapy. A bespoke phantom and motor-driven platform to replicate respiratory motion and study the consequences on tumour cell survival in vitro was constructed. Human non-small-cell lung cancer cell lines H460 and H1299 were irradiated in modulated radiotherapy configurations in the presence and absence of respiratory motion. Clonogenic survival was calculated for irradiated and shielded regions. Direction of motion, replication of dosimetry by multi-leaf collimator (MLC) manipulation and oscillating lead shielding were investigated to confirm differences in cell survival. Respiratory motion was shown to significantly increase survival for out-of-field regions for H460/H1299 cell lines when compared with static irradiation (p <0.001). Significantly higher survival was found in the in-field region for the H460 cell line (p <0.030). Oscillating lead shielding also produced these significant differences. Respiratory motion and oscillatory delivery of radiation dose to human tumour cells has a significant impact on in- and out-of-field survival in the presence of non-uniform irradiation in this in vitro set-up. This may have important radiobiological consequences for modulated radiotherapy in lung cancer. 

Investigation into the radiobiological consequences of pre-treatment verification imaging with megavoltage X-rays in radiotherapy

Objective: The aim of this study was to investigate the effect of pre-treatment verification imaging with megavoltage (MV) X-rays on cancer and normal cell survival in vitro and to compare the findings with theoretically modelled data. Since the dose received from pre-treatment imaging can be significant, incorporation of this dose at the planning stage of treatment has been suggested.

Methods: The impact of imaging dose incorporation on cell survival was investigated by clonogenic assay, irradiating DU-145 prostate cancer, H460 non-small cell lung cancer and AGO-1522b normal tissue fibroblast cells. Clinically relevant imaging-to-treatment times of 7.5 minutes and 15 minutes were chosen for this study. The theoretical magnitude of the loss of radiobiological efficacy due to sublethal damage repair was investigated using the Lea-Catcheside dose protraction factor model.

Results: For the cell lines investigated, the experimental data showed that imaging dose incorporation had no significant impact upon cell survival. These findings were in close agreement with the theoretical results.

Conclusions: For the conditions investigated, the results suggest that allowance for the imaging dose at the planning stage of treatment should not adversely affect treatment efficacy.

Advances in Knowledge: There is a paucity of data in the literature on imaging effects in radiotherapy. This paper presents a systematic study of imaging dose effects on cancer and normal cell survival, providing both theoretical and experimental evidence for clinically relevant imaging doses and imaging-to-treatment times. The data provide a firm foundation for further study into this highly relevant area of research.

Carotenoids and health in older people

As the proportion of older people increases, so will chronic disease incidence and the proportion of the population living with disability. Therefore, new approaches to maintain health for as long as possible in this age group are required. Carotenoids are a group of polyphenolic compounds found predominantly in fruit and vegetables that have been proposed to have anti-inflammatory and antioxidant effects. Such properties may impact on the risk diseases which predominate in older people, and also ageing-related physiological changes. Working out the effect of carotenoid intake versus fruit and vegetable intake is difficult, and the strong correlation between individual carotenoid intakes also complicates any attempt to examine individual carotenoid health effects. Similarly, research to determine whether carotenoids consumed as supplements have similar benefits to increased dietary intake through whole foods, is still required. However, reviewing the recent evidence suggests that carotenoid intake and status are relatively consistently associated with reduced CVD risk, although β-carotene supplementation does not reduce CVD risk and increases lung cancer risk. Increased lycopene intake may reduce prostate cancer progression, with a potential role for carotenoids at other cancer sites. Lutein and zeaxanthin have a plausible role in the maintenance of eye health, whilst an association between carotenoid intake and cognitive and physical health appears possible, although research is limited to date. Given this accruing evidence base to support a specific role for certain carotenoids and ageing, current dietary advice to consume a diet rich in fruit and vegetables would appear prudent, and efforts maintained to encourage increased intake.

Stereotactic Body Radiotherapy for Oligometastatic Disease

Stereotactic body radiotherapy (SBRT) is now an established therapy in stage I lung cancer with comparable local control rates to surgical resection. Owing to the conformity of treatment dose delivery and with appropriate fractionation considerations, minimal side-effects to surrounding normal tissues are observed in most patients. SBRT is now being used in the treatment of oligometastatic disease, alone or alongside systemic therapy. At present there is a paucity of evidence available showing a clinical benefit, but several international studies are being set-up or have started recruitment. This overview considers the clinical entity of an oligometastatic state, discusses the role of SBRT in the management of oligometastatic disease and discusses potential novel therapy combinations with SBRT.

Immune modulation in advanced radiotherapies: Targeting out-of-field effects

By virtue of being a localized treatment modality, radiotherapy is unable to deliver a tumoricidal radiation dose to tissues outside of the irradiated field. Nevertheless, ionizing radiation may result in radiation damage mediated by a bystander like effect away from the irradiated field, but this response is likely to be modest when radiotherapy is the sole treatment modality. Over the last decade there has been a re-emergence of immune modulating therapies as anti-cancer treatment modalities. Clinical trials on vaccines have on the whole been largely disappointing, but greater response rates have been observed from the immune checkpoint modulators. A clinical benefit of using such agents has been shown in disease sites such as melanoma and non-small cell lung cancer. There is growing pre-clinical data and a number of case reports which suggest the presence of abscopal effects when radiotherapy is co-administered with immune checkpoint inhibitors, suggesting that this combination may lead to an enhanced tumour response outside of the primary treatment field. In this review, the mechanisms of such an enhanced out-of-field tumour response, the potential clinical utilities, the optimal radiotherapy delivery and considerations for clinical follow-up following treatment are discussed.

Activation of human TLR4/MD-2 by hypoacylated lipopolysaccharide from a clinical isolate of Burkholderia cenocepacia

Lung infection by Burkholderia species, in particular B. cenocepacia, accelerates tissue damage and increase post-lung transplant mortality in cystic fibrosis patients. Host- microbes interplay largely depends on interactions between pathogen specific molecules and innate immune receptors such as the Toll-like receptor 4 (TLR4), which recognizes the lipid A moiety of the bacterial lipopolysaccharide (LPS). The human TLR4/MD-2 LPS receptor complex is strongly activated by hexa-acylated lipid A and poorly activated by underacylated lipid A. Here, we report that B. cenocepacia LPS strongly activates human TLR4/MD-2 despite its lipid A having only five acyl chains. Further, we show that aminoarabinose residues in lipid A contribute to TLR4-lipid A interactions, and experiments in a mouse model of LPS-induced endotoxic shock confirmed the pro- inflammatory potential of B. cenocepacia penta-acylated lipid A. Molecular modeling, combined with mutagenesis of TLR4-MD2 interactive surfaces, suggests that longer acyl chains and the aminoarabinose residues in the B. cenocepacia lipid A allow exposure of the fifth acyl chain on the surface of MD-2 enabling interactions with TLR4 and its dimerization. Our results provide a molecular model for activation of the human TLR4/MD- 2 complex by penta-acylated lipid A, explaining the ability of hypoacylated B. cenocepacia LPS to promote pro- inflammatory responses associated to the severe pathogenicity of this opportunistic bacterium.