Elevation of adenylate energy charge by angiopoietin-like 4 enhances epithelial-mesenchymal transition by inducing 14-3-3γ expression.

Metastatic cancer cells acquire energy-intensive processes including increased invasiveness and chemoresistance. However, how the energy demand is met and the molecular drivers that coordinate an increase in cellular metabolic activity to drive epithelial-mesenchymal transition (EMT), the first step of metastasis, remain unclear. Using different in vitro and in vivo EMT models with clinical patient's samples, we showed that EMT is an energy-demanding process fueled by glucose metabolism-derived adenosine triphosphate (ATP). We identified angiopoietin-like 4 (ANGPTL4) as a key player that coordinates an increase in cellular energy flux crucial for EMT via an ANGPTL4/14-3-3γ signaling axis. This augmented cellular metabolic activity enhanced metastasis. ANGPTL4 knockdown suppresses an adenylate energy charge elevation, delaying EMT. Using an in vivo dual-inducible EMT model, we found that ANGPTL4 deficiency reduces cancer metastasis to the lung and liver. Unbiased kinase inhibitor screens and Ingenuity Pathway Analysis revealed that ANGPTL4 regulates the expression of 14-3-3γ adaptor protein via the phosphatidylinositol-3-kinase/AKT and mitogen-activated protein kinase signaling pathways that culminate to activation of transcription factors, CREB, cFOS and STAT3. Using a different mode of action, as compared with protein kinases, the ANGPTL4/14-3-3γ signaling axis consolidated cellular bioenergetics and stabilized critical EMT proteins to coordinate energy demand and enhanced EMT competency and metastasis, through interaction with specific phosphorylation signals on target proteins.

Loss of TAK1 increases cell traction force in a ROS-dependent manner to drive epithelial-mesenchymal transition of cancer cells.

Epithelial-mesenchymal transition (EMT) is a crucial step in tumor progression, and the TGFß-SMAD signaling pathway as an inductor of EMT in many tumor types is well recognized. However, the role of non-canonical TGFß-TAK1 signaling in EMT remains unclear. Herein, we show that TAK1 deficiency drives metastatic skin squamous cell carcinoma earlier into EMT that is conditional on the elevated cellular ROS level. The expression of TAK1 is consistently reduced in invasive squamous cell carcinoma biopsies. Tumors derived from TAK1-deficient cells also exhibited pronounced invasive morphology. TAK1-deficient cancer cells adopt a more mesenchymal morphology characterized by higher number of focal adhesions, increase surface expression of integrin α5ß1 and active Rac1. Notably, these mutant cells exert an increased cell traction force, an early cellular response during TGFß1-induced EMT. The mRNA level of ZEB1 and SNAIL, transcription factors associated with mesenchymal phenotype is also upregulated in TAK1-deficient cancer cells compared with control cancer cells. We further show that TAK1 modulates Rac1 and RhoA GTPases activities via a redox-dependent downregulation of RhoA by Rac1, which involves the oxidative modification of low-molecular weight protein tyrosine phosphatase. Importantly, the treatment of TAK1-deficient cancer cells with Y27632, a selective inhibitor of Rho-associated protein kinase and antioxidant N-acetylcysteine augment and hinders EMT, respectively. Our findings suggest that a dysregulated balance in the activation of TGFß-TAK1 and TGFß-SMAD pathways is pivotal for TGFß1-induced EMT. Thus, TAK1 deficiency in metastatic cancer cells increases integrin:Rac-induced ROS, which negatively regulated Rho by LMW-PTP to accelerate EMT.

Oyster-associated outbreaks of Norovirus gastroenteritis in Singapore.

Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8h and the duration of illness was 2-3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3-24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.

Antimicrobial susceptibility testing of Haemophilus influenzae: trial organised as part of United Kingdom national external quality assessment scheme for microbiology.

Six strains of Haemophilus influenzae were distributed to 417 United Kingdom laboratories who were asked to test susceptibility of the strains to ampicillin, augmentin, tetracycline, chloramphenicol, and trimethoprim and to test for beta lactamase production. Laboratories were also asked to provide details of their methods by completing a questionnaire. The incidence of reports recording sensitive strains as resistant was 8% (ampicillin), 7% (augmentin), 3% (tetracycline), 1% (chloramphenicol), and 12% (trimethoprim). The incidence of reports recording resistant strains as sensitive was 9% (ampicillin), (2% with beta lactamase producing strains, 24% with non-beta lactamase producing strains), 51% (augmentin), 10% (tetracycline), 20% (chloramphenicol), and 3% (trimethoprim). High error rates were associated with several methods or practices. These included use of general purpose growth media rather than susceptibility testing media and failure to add lysed blood to the media when testing trimethoprim susceptibility; standardise the inoculum; use suitable control strains; and the use of high content discs for testing chloramphenicol, tetracycline, and ampicillin.

Prospective study of Clostridium difficile colonization and paracresol detection in the stools of babies on a special care unit.

Infants' stools were examined for the presence of Clostridium difficile and its cytotoxin in a study performed over a one-year period on a special care baby unit. Overall, 21% of infants were colonized, but the organism was only recovered in a seven-month period during which its weekly prevalence in the group varied from zero to 44%, with a distinct clustering of colonized infants being observed. Tests for the presence of cytotoxin in the stools and in supernatants of broth that had been inoculated with each isolate were negative. The factors predisposing to colonization were a prolonged stay in the unit, low birth weight, younger gestational age and being nursed in an incubator. The organism was recovered only once from an environmental screen. An antibiogram, used in conjunction with toxin production, was helpful in distinguishing these isolates from a collection obtained from other units in the hospital. We conclude that Cl. difficile was acquired by nosocomial spread although we did not establish the precise mechanism involved. The detection of para-cresol by gas-liquid chromatography was found to be specific but insufficiently sensitive as a screening test for the organism's presence in the stools. It could only be demonstrated in infants whose birth-weights were less than 2500 g, and no association was observed between the type of feed and para-cresol presence in stools.