DNA damage-induced BARD1 phosphorylation is critical for the inhibition of messenger RNA processing by BRCA1/BARD1 complex

BRCA1-associated RING domain protein BARD1, along with its heterodimeric partner BRCA1, plays important roles in cellular response to DNA damage. Immediate cellular response to genotoxic stress is mediated by a family of phosphoinositide 3-kinase-related protein kinases, such as ataxia-telangiectasia mutated (ATM), ATM and Rad3-related, and DNA-dependent protein kinase. ATM-mediated phosphorylation of BRCA1 enhances the DNA damage checkpoint functions of BRCA1, but how BARD1 is regulated during DNA damage signaling has not been examined. Here, we report that BARD1 undergoes phosphorylation upon ionizing radiation or UV radiation and identify Thr(714) as the in vivo BARD1 phosphorylation site. Importantly, DNA damage functions of BARD1 (i.e., inhibition of pre-mRNA polyadenylation and degradation of RNA polymerase II) are abrogated in T714A and T734A mutants. Our findings suggest that phosphorylation of BARD1 is critical for the DNA damage functions of the BRCA1/BARD1 complex.     

Health effects associated with indoor swimming pools: a suspected toxic chloramine exposure

OBJECTIVES: A cohort and environmental study tested the hypothesis that suspected exposure to chloramines (by-products of chlorine for disinfection and ammonia from human sources) from a hotel's indoor swimming pool was associated with an outbreak among children who had attended a party at the pool. STUDY DESIGN: Retrospective cohort study. METHODS: A case was defined as any hotel guest/visitor on 5-6 October 2002 who experienced three or more symptoms typical of chloramine exposure on either day after visiting the hotel. A cohort study and an environmental assessment were performed to determine the association between pool exposure and illness. RESULTS: Of 128 individuals interviewed, 32 met the case definition. Common symptoms among case patients were cough (84%), eye irritation (78%) and rash (34%). Illness was associated with entering the pool area [odds ratio (OR) 19.9; 95% confidence interval (CI) 2.3-172], but more strongly with swimming (OR 72.0; 95% CI 9.1-568). Pool chloramine levels on 6 October 2002 were > or = 0.7ppm (optimal level=0ppm; state maximum=0.5ppm). The pool operator lacked formal training in pool maintenance. CONCLUSIONS: High chloramine levels may have caused illness in individuals who were either in or near the pool. This outbreak underscores the need for regular pool maintenance, improved air quality, education and certification for all operators of public and semipublic pools, and education about healthy swimming practices.     

Genotoxicity analysis of two halonitromethanes, a novel group of disinfection by-products (DBPs), in human cells treated in vitro

Halonitromethanes (HNMs) constitute an emerging class of disinfection by-products (DBPs) produced when chlorine and/or ozone are used for water treatment. The HNMs are structurally similar to halomethanes, but have a nitro-group in place of hydrogen bonded to the central carbon atom. Since little information exists on the genotoxic potential of HNMs, a study has been carried out with two HNM compounds, namely trichloronitromethane (TCNM) and bromonitromethane (BNM) by using human cells. Primary damage induction has been measured with the Comet assay, which is used to determine both the repair kinetics of the induced damage and the proportion of induced oxidative damage. In addition, the fixed DNA damage has been evaluated by using the micronucleus (MN) assay. The results obtained indicate that both compounds are genotoxic, inducing high levels of DNA breaks in the Comet assay, and that this DNA damage repairs well over time. In addition, oxidized bases constitute a high proportion of DNA-induced damage (50-75%). Contrarily, no positive effects were observed in the frequency of micronucleus, which measures both clastogenic and aneugenic effects, neither using TK6 cells nor peripheral blood lymphocytes. This lack of fixed genetic damage would minimize the potential mutagenic risk associated with HNMs exposure.     

Novel Second-Generation Di-2-Pyridylketone Thiosemicarbazones Show Synergism with Standard Chemotherapeutics and Demonstrate Potent Activity against Lung Cancer Xenografts after Oral and Intravenous Administration in Vivo

We developed a series of second-generation di-2-pyridyl ketone thiosemicarbazone (DpT) and 2-benzoylpyridine thiosemicarbazone (BpT) ligands to improve the efficacy and safety profile of these potential antitumor agents. Two novel DpT analogues, Dp4e4mT and DpC, exhibited pronounced and selective activity against human lung cancer xenografts in vivo via the intravenous and oral routes. Importantly, these analogues did not induce the cardiotoxicity observed at high nonoptimal doses of the first-generation DpT analogue, Dp44mT. The Cu(II) complexes of these ligands exhibited potent antiproliferative activity having redox potentials in a range accessible to biological reductants. The activity of the copper complexes of Dp4e4mT and DpC against lung cancer cells was synergistic in combination with gemcitabine or cisplatin. It was demonstrated by EPR spectroscopy that dimeric copper compounds of the type [CuLCl](2), identified crystallographically, dissociate in solution to give monomeric 1:1 Cu:ligand complexes. These monomers represent the biologically active form of the complex.     

Manipulation of the nerve growth factor network in prostate cancer

Autocrine and paracrine events regulated by nerve growth factor (NGF) and relevant receptors (low- and high affinity; p75 neurotrophin receptor [p75(NTR)] and TrkA, respectively) seem to play a significant role in prostate carcinogenesis. Studies reveal that p75(NTR) is both a tumor suppressor of growth and a metastasis suppressor of human prostate cancer cells. Furthermore, p75(NTR) is progressively lost during prostate carcinogenesis. An imbalance between p75(NTR) and tropomyosin receptor kinase A (TrkA)-mediated signals may be involved in the progression of prostate cancer through increased proliferation and reduced apoptosis. The antiproliferative and apoptotic effects of GnRH analogs in prostate cancer cells may be mediated by altering the TrkA:p75(NTR) NGF receptor ratio. Administration of NGF induces a reversion of the androgen-independent/androgen receptor-negative prostate cancer cell lines to a less malignant phenotype. Finally, Trk inhibition is a novel, attractive and rational approach for prostate cancer therapy. This review unravels the NGF 'circuitry' in prostate cancinogenesis for relevant pharmacologic manipulation to lead to the development of novel therapeutic agents.     

Median arcuate ligament syndrome often poses a diagnostic challenge: A literature review with a scope of our own experience

The median arcuate ligament syndrome (MALS) is recognized as a rare clinical entity, characterized by chronic post-prandial abdominal pain, nausea, vomiting, and unintentional weight loss. Due to its vague symptomatology, it is mainly regarded as a diagnosis of exclusion. Patients can often be misdiagnosed for several years before a correct diagnosis is established, also due to a medical team’s clinical suspicion. We present a case series of two patients who suffered from MALS and were treated successfully. The first patient is a 32-year-old woman, presenting with post-prandial abdominal pain and weight loss that have lasted for the past ten years. The second patient, a 50-year-old woman, presented with similar symptomatology, with the symptoms lasting for the last five years. Both cases were treated by laparoscopic division of the median arcuate ligament fibers, which alleviated extrinsic pressure from the celiac artery. Previous cases of MALS were retrieved from PubMed, to assemble a better diagnostic algorithm and propose a treatment method of choice. The literature review suggests an angiography with a respiratory variation protocol as the diagnostic modality of choice, along with the laparoscopic division of the median arcuate ligament fibers as the proposed treatment of choice.