Frequent mutation in North African patients with MUTYH‐associated polyposis

Lefevre JH, Colas C, Coulet F, Baert‐Desurmont S, Mongin C, Tiret E, Frebourg T, Soubrier F, Parc Y. Frequent mutation in North African patients with MUTYH‐associated polyposis. MUTYH‐associated polyposis (MAP) has been characterized as an autosomal recessive disease predisposing to a variable number of colorectal adenomas with a high risk of cancer. Numerous studies have indicated that two missense mutations (Y179C and G396D) account for about 80% of MUTYH allelic variants in Europeans. Ethnic and geographic differences in the mutation spectrum have been observed. The aim of this study was to report mutations in patients from North Africa, determine the incidence of the c.1227_1228dup mutation in our cohort of MUTYH patients and to evaluate the existence of a founder effect. Within a group of 36 families with MAP, 11 were shown to have a homozygous c.1227_1228dup mutation. These families came from Algeria (n = 5), Tunisia (n = 4), Morocco (n = 1) and Portugal (n = 1). Probands belonging to families of North African origin showed a significantly higher frequency of c.1227_1228dup (78.6% vs 4.5%, p < 0.0001). Haplotype analyses were performed using 10 microsatellite markers surrounding the MUTYH gene spanning a region of 4.4 cM. We identified a common haplotype of at least 1.3 cM in all families suggesting a founder effect for this mutation.     

Influence of nucleotide polymorphisms in the CCR2 gene and the CCR5 promoter on the expression of cell surface CCR5 and CXCR4

Polymorphisms in the CCR2 gene (CCR2-64I) and the CCR5 promoter (pCCR5-59029G) have been correlated with slower HIV-1 disease progression. How these polymorphisms influence the rate of AIDS progression has remained unclear. We have therefore investigated whether these nucleotide polymorphisms will reduce the expression levels of surface CCR5 and CXCR4, and thus lead to slower AIDS progression. For this, a cohort of Chinese volunteers in Taiwan was subjected to the determination of CCR2 and pCCR5 genotypes followed by analysis of the surface CCR5 and CXCR4 expression on five cell types derived from peripheral blood mononuclear cells by flow cytometry. Several significant associations were detected between genotypes and expression levels of the proteins. The most important finding was that an increased number of CD4(+) cells expressing CCR5 correlated with pCCR5-59029A homozygosity without the interference of both the CCR2-64 and the CCR5 delta 32 (deleted 32 bp) mutations (P: = 0.0453), which is consistent with the previous data on the association of the genotype to AIDS progression. Since different genetic polymorphisms co-exist in human beings, the rate of AIDS progression as well as the risk of rheumatoid arthritis may be governed by the interplay of the array of nucleotide changes and their affected proteins.     

Genome-wide association study identifies breast cancer risk variant at 10q21.2: results from the Asia Breast Cancer Consortium

Although approximately 20 common genetic susceptibility loci have been identified for breast cancer risk through genome-wide association studies (GWASs), genetic risk variants reported to date explain only a small fraction of heritability for this common cancer. We conducted a four-stage GWAS including 17 153 cases and 16 943 controls among East-Asian women to search for new genetic risk factors for breast cancer. After analyzing 684 457 SNPs in 2062 cases and 2066 controls (Stage I), we selected for replication among 5969 Chinese women (4146 cases and 1823 controls) the top 49 SNPs that had neither been reported previously nor were in strong linkage disequilibrium with reported SNPs (Stage II). Three SNPs were further evaluated in up to 13 152 Chinese and Japanese women (6436 cases and 6716 controls) (Stage III). Finally, two SNPs were evaluated in 10 847 Korean women (4509 cases and 6338 controls) (Stage IV). SNP rs10822013 on chromosome 10q21.2, located in the zinc finger protein 365 (ZNF365) gene, showed a consistent association with breast cancer risk in all four stages with a combined per-risk allele odds ratio of 1.10 (95% CI: 1.07-1.14) (P-value for trend = 5.87 × 10(-9)). In vitro electrophoretic mobility shift assays demonstrated the potential functional significance of rs10822013. Our results strongly implicate rs10822013 at 10q21.2 as a genetic risk variant for breast cancer among East-Asian women.     

The insulin‐like growth factor system and sarcomas

Sarcomas are a diverse group of malignant mesenchymal tumours arising from bone and soft tissues. The identification of critical cellular signalling pathways in sarcomas is an important issue for the development of new targeted therapies. This review highlights the experimental and clinical evidence supporting the role of the insulin‐like growth factor (IGF) signalling system in the cellular transformation and progression of several types of sarcoma, including rhabdomyosarcoma, synovial sarcoma, leiomyosarcoma, Ewing's sarcoma and osteosarcoma. Preclinical data suggest that the IGF system could be a promising target for therapy in these sarcomas. Currently, therapies interrupting IGF signalling have been or are being developed. In recent phase 1 clinical studies with humanized monoclonal antibodies directed against IGF receptor type 1 (IGF‐1R), objective tumour responses were observed in several patients with Ewing's sarcoma, encouraging further clinical testing in Ewing's sarcoma and other sarcoma (sub)types. Moreover, the occasional occurrence of paraneoplastic hypoglycaemia as a result of the secretion of incompletely processed forms of pro‐IGF‐II by sarcomas is discussed. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Human heart beat analysis using a modified algorithm of detrended fluctuation analysis based on empirical mode decomposition

How to quantify the complexity of a physiological signal is a crucial issue for verifying the underlying mechanism of a physiological system. The original algorithm of detrended fluctuation analysis (DFA) quantifies the complexity of signals using the DFA scaling exponent. However, the DFA scaling exponent is suitable only for an integrated time series but not the original signal. Moreover, the method of least squares line is a simple detrending operation. Thus, the analysis results of the original DFA are not sufficient to verify the underlying mechanism of physiological signals. In this study, we apply an innovative timescale-adaptive algorithm of empirical mode decomposition (EMD) as the detrending operation for the modified DFA algorithm. We also propose a two-parameter scale of randomness for DFA to replace the DFA scaling exponent. Finally, we apply this modified algorithm to the database of human heartbeat interval from Physiobank, and it performs well in identifying characteristics of heartbeat interval caused by the effects of aging and of illness.     

Over‐expression of prothymosin‐α antagonizes TGFβ signalling to promote the development of emphysema

Emphysema, a major consequence of chronic obstructive pulmonary disease (COPD), is characterized by the permanent airflow restriction resulting from enlargement of alveolar airspace and loss of lung elasticity. Transforming growth factor‐β (TGFβ) signalling regulates the balance of matrix metalloproteinase (MMP)/tissue inhibitor of matrix metalloproteinase (TIMP) to control matrix homeostasis. Patients with COPD have dysregulated TGFβ signalling and reduced histone deacetylase (HDAC) activity through epigenetic up‐regulation of histone acetylation in the promoters of pro‐inflammatory genes. However, the potential link between decreased HDAC activity and dysregulated TGFβ signalling in emphysema pathogenesis remains to be determined. Prothymosin α (ProT), a highly conserved acidic nuclear protein, plays a role in the acetylation of histone and non‐histone proteins. The aim of this study was to test the hypothesis that ProT inhibits TGFβ–Smad signalling through Smad7, thereby contributing to emphysema pathogenesis. We show that ProT enhances Smad7 acetylation by decreasing its association with HDAC and thereby down‐regulates TGFβ–Smad signalling. ProT caused an imbalance between MMP and TIMP through acetylated Smad7 in favour of MMP expression. In addition to interfering with R‐Smad activation and targeting receptors for degradation in the cytoplasm, acetylated Smad7 potentiated by ProT competitively antagonized binding of the pSmad2/3–Smad4 complex to the TIMP‐3 promoter, resulting in reduced TIMP‐3 expression. These effects were detected in ProT‐over‐expressing cells, lungs of ProT transgenic mice displaying an emphysema phenotype and in emphysema patients. Importantly, increased Smad7 and reduced TIMP‐3 were found in the lungs of emphysema patients and mice with cigarette smoke extract (CSE)‐induced emphysema. Such effects could be abrogated by silencing endogenous ProT expression. Collectively, our results uncover acetylated Smad7 regulated by ProT as an important determinant in dysregulated TGFβ signalling that contributes to emphysema pathogenesis. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Waterborne Polyurethane Colloids with Sensitive CO2‐Switchable Hydrophilic/Hydrophobic Properties

A novel conceptual approach to gas‐responsive functionality, with the capability to tune the amphiphilic characteristics of existing waterborne polyurethanes (WPUs), via CO₂/N₂ bubbling in aqueous solution, is exploited. In this study, a series of functional WPUs are successfully prepared. These colloids exhibit high aqueous stability, excellent capability for emulsification/demulsification as a surfactant, and reversible hydrophilic/hydrophobic phase transition owing to reversible formation of carboxylic acid moieties induced by bubbling CO₂ gas. More interestingly, when carboxylated multiwalled carbon nanotubes (CNTs) are covalently incorporated into these WPUs, the CNT exhibits CO₂‐switchable amphiphilic behavior in a two‐phase mixture of n‐butanol (BuOH)/deionized water, forming a stable hydrophobic CNT dispersion in BuOH upon CO₂ bubbling, and reversibly reverting to the previous hydrophilic CNT dispersion in water upon N₂ bubbling. With simple preparation and switchable amphiphilic properties, these CO₂‐responsive WPUs offer a paradigm for the development of multifunctional gas‐responsive polymers.     

B1 but not B2 bradykinin receptor agonists promote DU145 prostate cancer cell proliferation and migration

Background

The kallikrein-kinin system (KKS) is an endogenous pathway involved in angiogenesis and tumourigenesis, both vital for cancer growth and progression.

Objectives

To investigate the effect of two bradykinin receptor (B1R and B2R) agonists on growth and motility of prostate tumour (DU145) and micro-vascular endothelial cells (dMVECs).

Methods

Increasing concentrations of selective B1R and B2R agonists were added to cultured cells. Cell proliferation and migration were assessed using the 3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and modified Boyden Chamber assays, respectively. Where significant stimulation was found, the influence of an antagonist was also investigated.

Results

Neither growth nor motility of endothelial cells was affected by either agonist. In DU145 cells, while the B2R agonist was without any significant effect, the B1R agonist stimulated proliferation and migration at concentrations of 10nM and 50nM respectively. Further, this effect was abrogated when cells were pre-incubated with a B1R antagonist.

Conclusions

Unlike the physiologically-active B2R, the pathologically-inducible B1R may be implicated in prostate tumourigenic events. The involvement of the KKS in malignant prostate pathology supports on-going exploration of bradykinin receptor antagonists as target candidates in the development of alternate approaches to cancer therapy.     

Superoxide activates very late antigen-4 on an eosinophil cell line and increases cellular binding to vascular cell adhesion molecule-1

The recruitment of eosinophils to the airway is a key event in the pathogenesis of allergy. Very late antigen-4 (VLA-4), an integrin ligand for vascular cell adhesion molecule-1 (VCAM-1), is expressed on eosinophils. VLA-4-mediated adhesion of eosinophils to VCAM-1 may contribute to their selective recruitment to tissues in allergy. Reactive oxygen species (ROS), including nitric oxide (NO), are abundant in the airway of allergic patients, but their role in pathogenesis of allergy is unclear. In this investigation, we studied the effects of ROS on integrin-mediated eosinophil adhesion. Recombinant soluble VCAM-1 and ICAM-1 were used to test the effects of ROS on the integrin-mediated adhesion of an eosinophil cell line. We used phorbol 12-myristate 13-acetate-stimulated neutrophils and hypoxanthine to generate superoxide, NO donors as sources of NO, and a static cell-to-protein adhesion assay to analyze cellular adhesion. Stimulated neutrophils significantly increased eosinophil binding to VCAM-1, which was reversed in the presence of superoxide dismutase. Neutrophils from a chronic granulomatous disease patient lacked this activity in enhancing eosinophil adhesion. Our results suggest that the balance between ROS molecules in different tissue microenvironments may change the integrin-mediated leukocyte adhesion and is likely to be a key factor in leukocyte recruitment in allergic inflammation.