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Summary Background The absence of trial data comparing robot-assisted laparoscopic prostatectomy and open radical retropubic prostatectomy is a crucial knowledge gap in uro-oncology. We aimed to compare these two approaches in terms of functional and oncological outcomes and report the early postoperative outcomes at 12 weeks. Method In this randomised controlled phase 3 study, men who had newly diagnosed clinically localised prostate cancer and who had chosen surgery as their treatment approach, were able to read and speak English, had no previous history of head injury, dementia, or psychiatric illness or no other concurrent cancer, had an estimated life expectancy of 10 years or more, and were aged between 35 years and 70 years were eligible and recruited from the Royal Brisbane and Women's Hospital (Brisbane, QLD). Participants were randomly assigned (1:1) to receive either robot-assisted laparoscopic prostatectomy or radical retropubic prostatectomy. Randomisation was computer generated and occurred in blocks of ten. This was an open trial; however, study investigators involved in data analysis were masked to each patient's condition. Further, a masked central pathologist reviewed the biopsy and radical prostatectomy specimens. Primary outcomes were urinary function (urinary domain of EPIC) and sexual function (sexual domain of EPIC and IIEF) at 6 weeks, 12 weeks, and 24 months and oncological outcome (positive surgical margin status and biochemical and imaging evidence of progression at 24 months). The trial was powered to assess health-related and domain-specific quality of life outcomes over 24 months. We report here the early outcomes at 6 weeks and 12 weeks. The per-protocol populations were included in the primary and safety analyses. This trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), number ACTRN12611000661976. Findings Between Aug 23, 2010, and Nov 25, 2014, 326 men were enrolled, of whom 163 were randomly assigned to radical retropubic prostatectomy and 163 to robot-assisted laparoscopic prostatectomy. 18 withdrew (12 assigned to radical retropubic prostatectomy and six assigned to robot-assisted laparoscopic prostatectomy); thus, 151 in the radical retropubic prostatectomy group proceeded to surgery and 157 in the robot-assisted laparoscopic prostatectomy group. 121 assigned to radical retropubic prostatectomy completed the 12 week questionnaire versus 131 assigned to robot-assisted laparoscopic prostatectomy. Urinary function scores did not differ significantly between the radical retropubic prostatectomy group and robot-assisted laparoscopic prostatectomy group at 6 weeks post-surgery (74·50 vs 71·10; p=0·09) or 12 weeks post-surgery (83·80 vs 82·50; p=0·48). Sexual function scores did not differ significantly between the radical retropubic prostatectomy group and robot-assisted laparoscopic prostatectomy group at 6 weeks post-surgery (30·70 vs 32·70; p=0·45) or 12 weeks post-surgery (35·00 vs 38·90; p=0·18). Equivalence testing on the difference between the proportion of positive surgical margins between the two groups (15 [10%] in the radical retropubic prostatectomy group vs 23 [15%] in the robot-assisted laparoscopic prostatectomy group) showed that equality between the two techniques could not be established based on a 90% CI with a Δ of 10%. However, a superiority test showed that the two proportions were not significantly different (p=0·21). 14 patients (9%) in the radical retropubic prostatectomy group versus six (4%) in the robot-assisted laparoscopic prostatectomy group had postoperative complications (p=0·052). 12 (8%) men receiving radical retropubic prostatectomy and three (2%) men receiving robot-assisted laparoscopic prostatectomy experienced intraoperative adverse events. Interpretation These two techniques yield similar functional outcomes at 12 weeks. Longer term follow-up is needed. In the interim, we encourage patients to choose an experienced surgeon they trust and with whom they have rapport, rather than a specific surgical approach. Funding Cancer Council Queensland.

Mutations in the ataxia-telangiectasia (A-T)-mutated (ATM) gene give rise to the human genetic disorder A-T, characterized by immunodeficiency, cancer predisposition, and neurodegeneration. Whereas a series of animal models recapitulate much of the A-T phenotype, they fail to present with ataxia or neurodegeneration. We describe here the generation of an Atm missense mutant [amino acid change of leucine (L) to proline (P) at position 2262 (L2262P)] rat by intracytoplasmic injection (ICSI) of mutant sperm into oocytes. Atm-mutant rats (AtmL2262P/L2262P) expressed low levels of ATM protein, suggesting a destabilizing effect of the mutation, and had a significantly reduced lifespan compared with Atm+/+. Whereas these rats did not show cerebellar atrophy, they succumbed to hind-limb paralysis (45%), and the remainder developed tumors. Closer examination revealed the presence of both dsDNA and ssDNA in the cytoplasm of cells in the hippocampus, cerebellum, and spinal cord of AtmL2262P/L2262P rats. Significantly increased levels of IFN-β and IL-1β in all 3 tissues were indicative of DNA damage induction of the type 1 IFN response. This was further supported by NF-κB activation, as evidenced by p65 phosphorylation (P65) and translocation to the nucleus in the spinal cord and parahippocampus. Other evidence of neuroinflammation in the brain and spinal cord was the loss of motor neurons and the presence of increased activation of microglia. These data provide support for a proinflammatory phenotype that is manifested in the Atm mutant rat as hind-limb paralysis. This mutant represents a useful model to investigate the importance of neuroinflammation in A-T.

Autosomal recessive ataxias are a clinically diverse group of syndromes that in some cases are caused by mutations in genes with roles in the DNA damage response, transcriptional regulation or mitochondrial function. One of these ataxias, known as Autosomal Recessive Cerebellar Ataxia Type-2 (ARCA-2, also known as SCAR9/COQ10D4; OMIM: #612016), arises due to mutations in the ADCK3 gene. The product of this gene (ADCK3) is an atypical kinase that is thought to play a regulatory role in coenzyme Q10 (CoQ10) biosynthesis. Although much work has been performed on the S. cerevisiae orthologue of ADCK3, the cellular and biochemical role of its mammalian counterpart, and why mutations in this gene lead to human disease is poorly understood. Here, we demonstrate that ADCK3 localises to mitochondrial cristae and is targeted to this organelle via the presence of an N-terminal localisation signal. Consistent with a role in CoQ10 biosynthesis, ADCK3 deficiency decreased cellular CoQ10 content. In addition, endogenous ADCK3 was found to associate in vitro with recombinant Coq3, Coq5, Coq7 and Coq9, components of the CoQ10 biosynthetic machinery. Furthermore, cell lines derived from ARCA-2 patients display signs of oxidative stress, defects in mitochondrial homeostasis and increases in lysosomal content. Together, these data shed light on the possible molecular role of ADCK3 and provide insight into the cellular pathways affected in ARCA-2 patients.

Glioblastoma multiforme (GBM) is the most common form of brain tumor with a poor prognosis and resistance to radiotherapy. Recent evidence suggests that glioma-initiating cells play a central role in radioresistance through DNA damage checkpoint activation and enhanced DNA repair. To investigate this in more detail, we compared the DNA damage response in nontumor forming neural progenitor cells (NPC) and glioma-initiating cells isolated from GBM patient specimens. As observed for GBM tumors, initial characterization showed that glioma-initiating cells have long-term self-renewal capacity. They express markers identical to NPCs and have the ability to form tumors in an animal model. In addition, these cells are radioresistant to varying degrees, which could not be explained by enhanced nonhomologous end joining (NHEJ). Indeed, NHEJ in glioma-initiating cells was equivalent, or in some cases reduced, as compared with NPCs. However, there was evidence for more efficient homologous recombination repair in glioma-initiating cells. We did not observe a prolonged cell cycle nor enhanced basal activation of checkpoint proteins as reported previously. Rather, cell-cycle defects in the G1–S and S-phase checkpoints were observed by determining entry into S-phase and radioresistant DNA synthesis following irradiation. These data suggest that homologous recombination and cell-cycle checkpoint abnormalities may contribute to the radioresistance of glioma-initiating cells and that both processes may be suitable targets for therapy. Mol Cancer Ther; 11(9); 1863–72. ©2012 AACR.

Pluripotent stem cells can differentiate into every cell type of the human body. Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) therefore provides an opportunity to gain insight into the molecular and cellular basis of disease. Because the cellular DNA damage response poses a barrier to reprogramming, generation of iPSCs from patients with chromosomal instability syndromes has thus far proven to be difficult. Here we demonstrate that fibroblasts from patients with ataxia-telangiectasia (A-T), a disorder characterized by chromosomal instability, progressive neurodegeneration, high risk of cancer, and immunodeficiency, can be reprogrammed to bona fide iPSCs, albeit at a reduced efficiency. A-T iPSCs display defective radiation-induced signaling, radiosensitivity, and cell cycle checkpoint defects. Bioinformatic analysis of gene expression in the A-T iPSCs identifies abnormalities in DNA damage signaling pathways, as well as changes in mitochondrial and pentose phosphate pathways. A-T iPSCs can be differentiated into functional neurons and thus represent a suitable model system to investigate A-T-associated neurodegeneration. Collectively, our data show that iPSCs can be generated from a chromosomal instability syndrome and that these cells can be used to discover early developmental consequences of ATM deficiency, such as altered mitochondrial function, that may be relevant to A-T pathogenesis and amenable to therapeutic intervention.

Snake venoms are attractive for drug discovery and development, with a number of therapeutics derived from snake venom either in clinical use or in development. Recognising this opportunity, Australian biopharmaceutical company QRxPharma Ltd and its subsidiary Venomics Pty Ltd (VPL) has partnered with the University of Queensland (UQ) to screen and develop drug candidates from Australian elapid snake venoms. VPL has three haemostasis candidates in early preclinical development. Textilinin-1 (Q8008) is a 7 kDa potent and selective plasmin inhibitor that has application as an anti-fibrinolytic agent to reduce blood loss associated with complex surgeries. Haempatch™ (Q8009) is a Factor Xa-like protein that displays potent procoagulant effects and is being developed as a topical haemostatic agent to reduce blood loss resulting from surgery or trauma. CoVase™ (V0801) is a procoagulant cofactor that may have application as a systemic anti-bleeding agent in the treatment of internal bleeding and non-compressible haemorrhage. This review focuses on drug discovery from Australian elapid snake venoms, with emphasis on the QRxPharma/VPL drug discovery project undertaken in collaboration with UQ and candidates at further stages of development.

As part of a wider study on Australian snake venom components, we have identified and characterised Kunitz-type protease inhibitors from the venoms of Oxyuranus scutellatus and Oxyuranus microlepidotus (Australian taipans) with plasma kallikrein inhibitory activity. Each inhibitor had a mass of 7 kDa and was purified from the venom as part of a protein complex. Mass spectrometry and N-terminal sequencing was employed to obtain amino acid sequence information for each inhibitor and a recombinant form of the O. scutellatus inhibitor, termed TSPI, was subsequently expressed and purified. TSPI was investigated for inhibition against a panel of 12 enzymes involved in haemostasis and estimates of the K i value determined for each enzyme. TSPI was found to be a broad spectrum inhibitor with most potent inhibitory activity observed against plasma kallikrein that corresponded to a K i of 0.057 ± 0.019 nM. TSPI also inhibited fibrinolysis in whole blood and prolonged the intrinsic clotting time. These inhibitors are also unique in that they appear to be found only in Oxyuranus sp. venoms.

Ataxia-telangiectasia, mutated (ATM) protein plays a central role in phosphorylating a network of proteins in response to DNA damage. These proteins function in signaling pathways designed to maintain the stability of the genome and minimize the risk of disease by controlling cell cycle checkpoints, initiating DNA repair, and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here, we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach to identify cytoplasmic proteins altered in their phosphorylation state in control and ataxia-telangiectasia (A-T) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites, including 6,686 high-confidence sites mapping to 2,536 unique proteins. A total of 62 differentially phosphorylated peptides were identified; of these, 43 were phosphorylated in control but not in A-T cells, and 19 varied in their level of phosphorylation. Motif enrichment analysis of phosphopeptides revealed that consensus ATM serine glutamine sites were overrepresented. When considering phosphorylation events, only observed in control cells (not observed in A-T cells), with predicted ATM sites phosphoSerine/phosphoThreonine glutamine, we narrowed this list to 11 candidate ATM-dependent cytoplasmic proteins. Two of these 11 were previously described as ATM substrates (HMGA1 and UIMCI/RAP80), another five were identified in a whole cell extract phosphoproteomic screens, and the remaining four proteins had not been identified previously in DNA damage response screens. We validated the phosphorylation of three of these proteins (oxidative stress responsive 1(OSR1), HDGF, and ccdc82) as ATM dependent after H 2O 2 exposure, and another protein (S100A11) demonstrated ATM-dependence for translocation from the cytoplasm to the nucleus. These data provide new insights into the activation of ATM by oxidative stress through identification of novel substrates for ATM in the cytoplasm.

Cancer incidence in schizophrenia is not increased commensurate with higher rates of risk exposures. Here we report an investigation of the DNA damage response, an anti-tumorigenic defence, in immortalised lymphoblasts from patients with schizophrenia.Unirradiated and irradiated (5Gy) lymphoblasts from schizophrenia patients (n = 28) and healthy controls (n = 28) were immunostained for the phosphorylated histone variant H2AX (γH2AX), an index of DNA double-strand breaks. Flow cytometry was used to assess cell cycle distribution and γH2AX immunofluorescence. Rate of DNA repair was quantified by determining the temporal change in γH2AX values following irradiation.In unirradiated lymphoblasts, γH2AX levels were significantly increased in the schizophrenia group compared with controls (effect size = 0.86). This increase was most evident in patients with cognitive deficits. In irradiated lymphoblasts, peak radiation-induced γH2AX levels were significantly reduced in patients. No differences between patients and controls were found in the rate of DNA repair or in cell cycle distribution.The significant differences in DNA damage response signalling observed involve modification of histone variant H2AX and thereby implicate regulatory processes determining chromatin structure in dividing lymphoblasts from patients with schizophrenia. The role that aberrant DNA damage response signalling plays in protecting patients from cancer is unclear.

ATM is the most significant molecule involved in monitoring the genomic integrity of the cell. Any damage done to DNA relentlessly challenges the cellular machinery involved in recognition, processing and repair of these insults. ATM kinase is activated early to detect and signal lesions in DNA, arrest the cell cycle, establish DNA repair signaling and faithfully restore the damaged chromatin. ATM activation plays an important role as a barrier to tumorigenesis, metabolic syndrome and neurodegeneration. Therefore, studies of ATM-dependent DNA damage signaling pathways hold promise for treatment of a variety of debilitating diseases through the development of new therapeutics capable of modulating cellular responses to stress. In this review, we have tried to untangle the complex web of ATM signaling pathways with the purpose of pinpointing multiple roles of ATM underlying the complex phenotypes observed in AT patients.

Snake venoms contain a complex mixture of polypeptides that modulate prey homeostatic mechanisms through highly specific and targeted interactions. In this study we have identified and characterised cystatin-like cysteine-protease inhibitors from elapid snake venoms for the first time. Novel cystatin sequences were cloned from 12 of 13 elapid snake venom glands and the protein was detected, albeit at very low levels, in a total of 22 venoms. One highly conserved isoform, which displayed close sequence identity with family 2 cystatins, was detected in each elapid snake. Crude Austrelaps superbus (Australian lowland copperhead) snake venom inhibited papain, and a recombinant form of A. superbus cystatin inhibited cathepsin L ≅ papain > cathepsin B, with no inhibition observed for calpain or legumain. While snake venom cystatins have truncated N-termini, sequence alignment and structural modelling suggested that the evolutionarily conserved Gly-11 of family 2 cystatins, essential for cysteine protease inhibition, is conserved in snake venom cystatins as Gly-3. This was confirmed by mutagenesis at the Gly-3 site, which increased the dissociation constant for papain by 104-fold. These data demonstrate that elapid snake venom cystatins are novel members of the type 2 family. The widespread, low level expression of type 2 cystatins in snake venom, as well as the presence of only one highly conserved isoform in each species, imply essential housekeeping or regulatory roles for these proteins.

C-type lectins are calcium-dependent sugar binding proteins and are distributed ubiquitously amongst vertebrate organisms. As part of a wider study on Australian snake venom components, we have identified and characterised a C-type lectin from the venom of Oxyuranus scutellatus (Australian coastal taipan) with mannose-binding activity. This protein exhibited a subunit molecular mass of 15 kDa and was found to bind mannose and also bind to and agglutinate erythrocytes in a Ca(2+)-dependent manner. cDNA transcripts coding for C-lectin proteins were cloned and sequenced from six Australian elapid snake species and an antibody generated against the O. scutellatus mannose-binding C-lectin identified C-lectin proteins in the venom of 13 Australian elapid snakes by immunoblotting. Experimental evidence and molecular modelling also suggest that this protein exhibits a unique dimeric structure. This is the first confirmed example of a snake venom C-lectin with mannose-binding activity.

The recognition and signaling of DNA double strand breaks involves the participation of multiple proteins, including the protein kinase ATM (mutated in ataxia-telangiectasia). ATM kinase is activated in the vicinity of the break and is recruited to the break site by the Mre11-Rad50-Nbs1 complex, where it is fully activated. In human cells, the activation process involves autophosphorylation on three sites (Ser(367), Ser(1893), and Ser(1981)) and acetylation on Lys(3016). We now describe the identification of a new ATM phosphorylation site, Thr(P)(1885) and an additional autophosphorylation site, Ser(P)(2996), that is highly DNA damage-inducible. We also confirm that human and murine ATM share five identical phosphorylation sites. We targeted the ATM phosphorylation sites, Ser(367) and Ser(2996), for further study by generating phosphospecific antibodies against these sites and demonstrated that phosphorylation of both was rapidly induced by radiation. These phosphorylations were abolished by a specific inhibitor of ATM and were dependent on ATM and the Mre11-Rad50-Nbs1 complex. As found for Ser(P)(1981), ATM phosphorylated at Ser(367) and Ser(2996) localized to sites of DNA damage induced by radiation, but ATM recruitment was not dependent on phosphorylation at these sites. Phosphorylation at Ser(367) and Ser(2996) was functionally important because mutant forms of ATM were defective in correcting the S phase checkpoint defect and restoring radioresistance in ataxia-telangiectasia cells. These data provide further support for the importance of autophosphorylation in the activation and function of ATM in vivo.

In our commitment to developing a non-invasive test for prostate cancer detection, we identifi ed a short list of discriminating mRNA markers in prostatic tissues to complement the non-coding gene PCA3 for use in molecular profiling of prostatic fluid. RT-PCR for PCA3 and Hepsin from ejaculate together with serum PSA provided a sensitivity of 75% with a specifi city of 85% in the detection of prostate cancer from 75 patients. Since the addition of further mRNA markers only marginally improved these results, we have extended our investigations to include microRNA, metabonomic and Dkk-3 protein analyses. BMMC1, the gene in which PCA3 is embedded, is also being examined to establish binding partners to determine the role of this gene in prostate cancer. Preliminary analyses of multiple parameters with metabonomics of ejaculate from 80 patients have demonstrated Gleason score to be most closely aligned as clinical parameter. However, serum PSA by itself was positioned at almost 90 degrees off from the axis delineating cancer status and cancer severity indicating its lack of relationship with severity of cancer. Dkk-3, one of the secreted glycoproteins of the Dickkopf family, also promises to be a useful discriminator with Dkk-3 levels in 80 patients’ ejaculates being signifi cantly different in prostate cancer and TRUS negative patient specimens. An update of our integrated marker findings from ejaculate specimens obtained from ≥100 patients between 2007 and 2010 will be presented.

Accurate identification of patients with early prostate cancer warranting treatment with curative intent remains problematic, with various approaches proposed to detect the presence of high-risk disease. In this issue of European Urology, Van Neste et al [1] report findings for an approach in which two mRNA markers, homeobox genes HOXC6 and DLX1, are combined with traditional clinical risk factors used in the Prostate Cancer Prevention Trial (PRCPT) risk calculator. This group previously identified these genes and used them with TDRD1 in a urinary three-gene panel that had higher accuracy than PCA3 or serum prostate specific antigen (PSA) [2] in predicting prostate cancer (Gleason score [2_TD$DIFF] 7). Two sequential multicentre clinical trials undertaken from 2009 to 2014 in The Netherlands included 519 men in a training cohort and 386 in a validation cohort. Expression levels ofHOXC6 and DLX1mRNA combined with serum PSA, PSA density, digital rectal examination (DRE), age, and family history yielded an overall area under the curve (AUC) of 0.90 (95% confidence interval [CI] 0.85–0.95) for the validation cohort (AUC 0.86 for the training cohort). The authors determined that serum PSA, family history, and age were no longer significant predictorswhenHOXC6 andDLX1 were included. Interestingly, addition of the commercial Progensa PCA3 previously promoted by this group did not improve predictability. The authors are to be congratulated for their approach in developing a well-established calculator by incorporating molecular profiling in a clinician-friendly manner for potential routine use. Because of the very promising findings reported here, it is expected that these markers

Background At present, occupational noise exposure has become one of the risk factors of occupational workers and attracted serious concerned of most of occupational disease researchers. To assess associations of occupational noise exposure and cardiovascular disease by meta-analysis. Methods and analysis Results from primary studies about occupational noise and cardiovascular disease (2000-2017) were retrieved from literatures, which were conducted in China only. Both random and fixed effect model were used to calculate pooled odds ratio (OR) and their corresponding 95% confidence interval (CI). Review Manager and Stata software were used to perform data analysis. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements. Results After applying stringent inclusion and exclusion criteria, 4771 exposures and 3068 controls from 11 primary studies were used to analyze the relationship between occupational noise exposure and cardiovascular disease. The risk of developing high blood pressure for workers exposed to noise is 2.55 times higher than the controls (I = 52%, 95% CI: 1.94-3.36), and electrocardiograph (ECG) abnormality is 2.27 times higher than the control groups (I = 22%, 95% CI: 1.96-2.62). The bias analysis suggested that there is publication bias, but it didn't affect the conclusions from trim test. Conclusion The impact of high-intensity noise exposure on the worker's cardiovascular system is much greater than that of the unexposed control group, and the effect on hypertension of the exposed group is greater than that of the ECG.

Early detection of prostate cancer is problematic, not just because of uncertainly whether a diagnosis will benefit an individual patient, but also as a result of the imprecise and invasive nature of establishing a diagnosis by biopsy. Despite its low sensitivity and specificity for identifying patients harbouring prostate cancer, serum prostate specific antigen (PSA) has become established as the most reliable and widely-used diagnostic marker for this condition. In its wake, many other markers have been described and evaluated. This review focuses on the supporting evidence for the most prominent of these for detection and also for predicting outcome in prostate cancer.

Introduction: Unlike prostatic massage,ejaculate contains seminal plasma as well asdisaggregated prostatic cells. In addition, ejaculateis more likely to reflect contributions from allparts of the gland as opposed to prostaticmassage which targets only the back of theprostate. A further concern with prostaticmassage is the potential risk of seeding prostatecancer cells systemically.We employed a short list of discriminatingmRNA markers to complement the non-codinggene PCA3 for molecular profiling of prostaticfluid. Initial testing for PCA3 in ejaculateindicated a 63% sensitivity and 72.5%specificity for 71 patients, consistent withfindings for post-prostatic massage urine-basedstudies. However, in keeping with ourhypothesis that multiple markers will berequired for accurate detection of prostatecancer, it has become obvious that PCA3 byitself is inadequate in the non-invasivedetection of prostate cancer.Methods: Seventy-five men, prior toproceeding to TRUS biopsy, provided ejaculate. RNAwas extracted, expanded and stored as cDNA priorto PCR for b2M & PSA (reference markers), PCA3,Hepsin, PSMA and Claudin 4. Data analysisincluded serum PSA. More recently we haveincluded PCR for TMPRSS2:ERG to our profile andare currently integrating metabonomicprofiling with NMR spectroscopy forcitrate, choline, spermidine, TMAO and betaine.Results and Conclusions: Based on ROCfindings for PCA3 plus Hepsin plus serum PSA,a sensitivity of 77%, a specificity of 68% for anegative predictive value of 77%. was providedThese results will be updated and combinedwith those from fusion gene RT-PCR and NMRspectroscopy.

Aprotinin has been used widely in surgery as an anti-bleeding agent but is associated with a number of side effects. We report that textilinin-1, a serine protease inhibitor from Pseudonaja textilis venom with sequence relatedness to aprotinin, is a potent but reversible plasmin inhibitor and has a narrower range of protease inhibition compared to aprotinin. Like aprotinin, textilinin-1 at 5 micromol/l gave almost complete inhibition of tissue plasminogen activator-induced fibrinolysis of whole blood clots. The activated partial thromboplastin time for plasma was markedly increased by aprotinin but unaffected by textilinin-1. In a mouse tail-vein bleeding model, intravenous textilinin-1 and aprotinin caused similar decreases in blood loss but time to haemostasis in the textilinin-treated animals was significantly shorter than in aprotinin-treated mice. Based on these data, textilinin-1 merits further investigation as a therapeutic alternative to aprotinin.

Malignant myoepithelioma of the breast (MMB) is a rare and often aggressive disease with poor prognosis. Little is known regarding its optimal treatment and progression. We describe the clinical history of a woman following excision of a benign adenomyoepithelioma which recurred years later as a radioresistant malignant myoepithelioma with high levels of ataxia telangiectasia mutated protein and mutant p53 (Cys135Phe). MMB requires close follow-up and aggressive treatment. If adjuvant radiotherapy is adopted to improve local control, minimal postoperative delay and higher doses than for standard post-mastectomy radiation are recommended.

First described over 80 years ago, ataxia-telangiectasia (A-T) was defined as a clinical entity 50 years ago. Although not encountered by most clinicians, it is a paradigm for cancer predisposition and neurodegenerative disorders and has a central role in our understanding of the DNA-damage response, signal transduction and cell-cycle control. The discovery of the protein A-T mutated (ATM) that is deficient in A-T paved the way for rapid progress on understanding how ATM functions with a host of other proteins to protect against genome instability and reduce the risk of cancer and other pathologies.

In experimental neuro-oncology there remains a need for animal models that can be used to assess the efficacy of new and innovative treatment methodologies for glioblastoma multiforme (GBM). Rat models have remained the mainstay of neuro-oncology research for over 30 years; however, despite extensive experimentation, there is no one rat model that truly reflects the features of human tumours. We have developed a novel rat brain tumour model that closely resembles human GBM in biological behaviour and that utilizes bioluminescence imaging (BLI) to follow day-to-day in vivo progress of the tumour. F98 glioma cells were transfected with the firefly luciferase gene and injected orthotopically into the brains of 24 rats. Weekly BLI after subcutaneous injection of luciferin allowed for in vivo monitoring of the progress of the brain tumours. Euthanasia and histological analysis of the rodent brains at varying stages post-implantation, allowed for statistically significant correlation between tumour size and luminescence (p = 0.002). The utility of this model is readily apparent, allowing us a way of examining the effects of new and novel therapeutics in these rats.

The recognition and repair of DNA double-strand breaks (DSBs) is a complex process that draws upon a multitude of proteins. This is not surprising since this is a lethal lesion if left unrepaired and also contributes to genome instability and the consequential risk of cancer and other pathologies. Some of the key proteins that recognize these breaks in DNA are mutated in distinct genetic disorders that predispose to agent sensitivity, genome instability, cancer predisposition and/or neurodegeneration. These include members of the Mre11 complex (Mre11/Rad50/Nbs1) and ataxia-telangiectasia (A-T) mutated (ATM), mutated in the human genetic disorder A-T. The mre11 (MRN) complex appears to be the major sensor of the breaks and subsequently recruits ATM where it is activated to phosphorylate in turn members of that complex and a variety of other proteins involved in cell-cycle control and DNA repair. The MRN complex is also upstream of ATM and ATR (A-T-mutated and rad3-related) protein in responding to agents that block DNA replication. To date, more than 30 ATM-dependent substrates have been identified in multiple pathways that maintain genome stability and reduce the risk of disease. We focus here on the relationship between ATM and the MRN complex in recognizing and responding to DNA DSBs.

ATM, the protein mutated in the human genetic disorder ataxia-telangiectasia, functions by responding to radiation damage to DNA, primarily DNA double strand breaks (dsb), to reduce the risk of genome instability, cancer and neurodegeneration. ATM is rapidly activated as an existing protein to phosphorylate a number of downstream proteins that are involved in DNA repair and cell cycle checkpoint activation. While the exact mechanism of activation of ATM has not been determined, it is now evident that it relies heavily on the Mre11 complex (Mre11/Rad50/Nbs1) and a series of post-translational events for this activation. The Mre11 complex acts as a sensor for the break, recruits ATM to this site where it is autophosphorylated and then is capable of phosphorylating substrates that participate in DNA repair and cell cycle control. A greater understanding of how ATM is activated and functions through different signalling pathways is paramount to devising therapeutic strategies for the treatment of A-T patients. This knowledge can also be used to advantage in sensitizing cells to radiation and ultimately deriving novel therapeutic approaches for the treatment of cancer.

A subgroup of human autosomal recessive ataxias is also characterized by disturbances of eye movement or oculomotor apraxia. These include ataxia telangiectasia (A-T); ataxia telangiectasia like disorder (ATLD); ataxia oculomotor apraxia type 1 (AOA1) and ataxia oculomotor apraxia type 2 (AOA2). What appears to be emerging is that all of these have in common some form of defect in DNA damage response which could account for the neurodegenerative changes seen in these disorders. We describe here sensitivity to DNA damaging agents in AOA1 and evidence that these cells have a defect in single strand break repair. Comparison is made with what appears to be a novel form of AOA (AOA3) which also shows sensitivity to agents that lead to single strand breaks in DNA as well as a reduced capacity to repair these breaks. AOA3 cells are defective in the DNA damage-induced p53 response. This defect can be overcome by incubation with the mdm2 antagonists, nutlins, but combined treatment with nutlins and DNA damage does not enhance the response. We also show that AOA3 cells are deficient in p73 activation after DNA damage. These data provide further evidence that different forms of AOA have in common a reduced capacity to cope with damage to DNA, which may account for the neurodegeneration observed in these syndromes.

Several different autosomal recessive genetic disorders characterized by ataxia with oculomotor apraxia (AOA) have been identified with the unifying feature of defective DNA damage recognition and/or repair. We describe here the characterization of a novel form of AOA showing increased sensitivity to agents that cause single-strand breaks (SSBs) in DNA but having no gross defect in the repair of these breaks. Evidence for the presence of residual SSBs in DNA was provided by dramatically increased levels of poly (ADP-ribose)polymerase (PARP-1) auto-poly (ADP-ribosyl)ation, the detection of increased levels of reactive oxygen/nitrogen species (ROS/RNS) and oxidative damage to DNA in the patient cells. There was also evidence for oxidative damage to proteins and lipids. Although these cells were hypersensitive to DNA damaging agents, the mode of death was not by apoptosis. These cells were also resistant to TRAIL-induced death. Consistent with these observations, failure to observe a decrease in mitochondrial membrane potential, reduced cytochrome c release and defective apoptosis-inducing factor translocation to the nucleus was observed. Apoptosis resistance and PARP-1 hyperactivation were overcome by incubating the patient's cells with antioxidants. These results provide evidence for a novel form of AOA characterized by sensitivity to DNA damaging agents, oxidative stress, PARP-1 hyperactivation but resistance to apoptosis.

Senataxin, defective in ataxia oculomotor apraxia type 2, protects the genome by facilitating the resolution of RNA–DNA hybrids (R-loops) and other aspects of RNA processing. Disruption of this gene in mice causes failure of meiotic recombination and defective meiotic sex chromosome inactivation, leading to male infertility. Here we provide evidence that the disruption of Setx leads to reduced SUMOylation and disruption of protein localization across the XY body during meiosis. We demonstrate that senataxin and other DNA damage repair proteins, including ataxia telangiectasia and Rad3-related protein-interacting partner, are SUMOylated, and a marked downregulation of both ataxia telangiectasia and Rad3-related protein-interacting partner and TopBP1 leading to defective activation and signaling through ataxia telangiectasia and Rad3-related protein occurs in the absence of senataxin. Furthermore, chromodomain helicase DNA-binding protein 4, a component of the nucleosome remodeling and deacetylase chromatin remodeler that interacts with both ataxia telangiectasia and Rad3-related protein and senataxin was not recruited efficiently to the XY body, triggering altered histone acetylation and chromatin conformation in Setx−/− pachytene-staged spermatocytes. These results demonstrate that senataxin has a critical role in ataxia telangiectasia and Rad3-related protein- and chromodomain helicase DNA-binding protein 4-mediated transcriptional silencing and chromatin remodeling during meiosis providing greater insight into its critical role in gene regulation to protect against neurodegeneration.

Background Our understanding of the effect of ataxia–telangiectasia mutated gene mutations on brain structure and function is limited. In this study, white matter motor pathway integrity was investigated in ataxia telangiectasia patients using diffusion MRI and probabilistic tractography. Methods Diffusion MRI were obtained from 12 patients (age range: 7–22 years, mean: 12 years) and 12 typically developing age matched participants (age range 8–23 years, mean: 13 years). White matter fiber tracking and whole tract statistical analyses were used to assess quantitative fractional anisotropy and mean diffusivity differences along the cortico-ponto-cerebellar, cerebellar-thalamo-cortical, somatosensory and lateral corticospinal tract length in patients using a linear mixed effects model. White matter tract streamline number and apparent fiber density in patient and control tracts were also assessed. Results Reduced fractional anisotropy along all analyzed patient tracts were observed (p, Highlights • Corticomotor and corticospinal ataxia telangiectasia patient tracts were analyzed. • Decreases in fractional anisotropy occurred along patient tracts. • Mean diffusivity was reduced in cerebellar peduncles in patients. • Patient corticospinal streamline number and apparent fiber density were reduced. • Young ataxia telangiectasia patients show advanced white matter degeneration.

The human helicase senataxin (SETX) has been linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS4) and ataxia with oculomotor apraxia (AOA2). Here we identified a role for SETX in controlling the antiviral response. Cells that had undergone depletion of SETX and SETX-deficient cells derived from patients with AOA2 had higher expression of antiviral mediators in response to infection than did wild-type cells. Mechanistically, we propose a model whereby SETX attenuates the activity of RNA polymerase II (RNAPII) at genes stimulated after a virus is sensed and thus controls the magnitude of the host response to pathogens and the biogenesis of various RNA viruses (e.g., influenza A virus and West Nile virus). Our data indicate a potentially causal link among inborn errors in SETX, susceptibility to infection and the development of neurologic disorders.

Ataxia oculomotor apraxia type 2 (AOA2) is a rare autosomal recessive cerebellar ataxia. Recent evidence suggests that the protein defective in this syndrome, senataxin (SETX), functions in RNA processing to protect the integrity of the genome. To date, only patient-derived lymphoblastoid cells, fibroblasts and SETX knockdown cells were available to investigate AOA2. Recent disruption of the Setx gene in mice did not lead to neurobehavioral defects or neurodegeneration, making it difficult to study the etiology of AOA2. To develop a more relevant neuronal model to study neurodegeneration in AOA2, we derived neural progenitors from a patient with AOA2 and a control by induced pluripotent stem cell (iPSC) reprogramming of fibroblasts. AOA2 iPSC and neural progenitors exhibit increased levels of oxidative damage, DNA double-strand breaks, increased DNA damage-induced cell death and R-loop accumulation. Genome-wide expression and weighted gene co-expression network analysis in these neural progenitors identified both previously reported and novel affected genes and cellular pathways associated with senataxin dysfunction and the pathophysiology of AOA2, providing further insight into the role of senataxin in regulating gene expression on a genome-wide scale. These data show that iPSCs can be generated from patients with the autosomal recessive ataxia, AOA2, differentiated into neurons, and that both cell types recapitulate the AOA2 cellular phenotype. This represents a novel and appropriate model system to investigate neurodegeneration in this syndrome.

Universal embryonic stem cell donor lines would greatly facilitate stem cell based regenerative medicine and permit facile testing of human pluripotent stem cell derived grafts in xenogeneic settings. Because HLA-G overcomes immune cell mediated attack of foetal tissues during pregnancy and inhibits T-cell responses and dendritic cell antigen maturation in vitro and in vivo, it is an attractive candidate molecule for achieving this goal. Here we investigated whether enforced expression of either the soluble or the membrane bound form of the HLA-G mouse homologue, H2- Bl, in human and mouse ES cell lines would allow engraftment in immunocompetent mice. Despite evidence for robust expression of soluble or membrane bound H2-Bl molecules and effective inhibition of CD8+ T-cell proliferation by all H2-Bl engineered ES cell lines, all failed to generate teratomas in immunocompetent mice, despite doing so in NODSCID mice. We conclude that expression of H2-Bl in human and mouse embryonic stem cells alone is insufficient to overcome xenogeneic rejection.

The Australian elapid snakes are amongst the most venomous snakes in the world, but much less is known about the overall venom composition in comparison to Asian and American snakes. We have used a combined approach of cDNA cloning and 2-DE with MS to identify nerve growth factor (NGF) in venoms of the Australian elapid snakes and demonstrate its neurite outgrowth activity. While a single 730 nucleotide ORF, coding for a 243 amino acid precursor protein was detected in all snakes, use of 2-DE identified NGF proteins with considerable variation in molecular size within and between the different snakes. The variation in size can be explained at least in part by N-linked glycosylation. It is possible that these modifications alter the stability, activity and other characteristics of the snake NGFs. Further characterisation is necessary to delineate the function of the individual NGF isoforms.

Mutations in the ATM gene (mutated in ataxia telangiectasia) in both humans and mice predispose to lymphoid tumors. A defect in this gene also causes neurodegeneration in humans and a less severe neurological phenotype in mice. There is some evidence that oxidative stress contributes to these defects, suggesting that antioxidants could alleviate the phenotype. We demonstrate here that the antioxidant 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO) dramatically delays the onset of thymic lymphomas in Atm(-/-) mice which is not due to an enhancement of apoptosis by CTMIO. We also show that this compound corrects neurobehavioral deficits in these mice and reduces oxidative damage to Purkinje cells. The likely mechanism of action of CTMIO is due to a reduction in oxidative stress, which is protective against both the tumor progression and the development of neurological abnormalities. These data suggest that antioxidant therapy has considerable potential in the management of ataxia telangiectasia and possibly other neurodegenerative disorders where oxidative stress is implicated.

ATM kinase plays a central role in signaling DNA double-strand breaks to cell cycle checkpoints and to the DNA repair machinery. Although the exact mechanism of ATM activation remains unknown, efficient activation requires the Mre11 complex, autophosphorylation on S1981 and the involvement of protein phosphatases and acetylases. We report here the identification of several additional phosphorylation sites on ATM in response to DNA damage, including autophosphorylation on pS367 and pS1893. ATM autophosphorylates all these sites in vitro in response to DNA damage. Antibodies against phosphoserine 1893 revealed rapid and persistent phosphorylation at this site after in vivo activation of ATM kinase by ionizing radiation, paralleling that observed for S1981 phosphorylation. Phosphorylation was dependent on functional ATM and on the Mre11 complex. All three autophosphorylation sites are physiologically important parts of the DNA damage response, as phosphorylation site mutants (S367A, S1893A and S1981A) were each defective in ATM signaling in vivo and each failed to correct radiosensitivity, genome instability and cell cycle checkpoint defects in ataxia-telangiectasia cells. We conclude that there are at least three functionally important radiation-induced autophosphorylation events in ATM.

The APTX gene, mutated in patients with the neurological disorder ataxia with oculomotor apraxia type 1 (AOA1), encodes a novel protein aprataxin. We describe here, the interaction and interdependence between aprataxin and several nucleolar proteins, including nucleolin, nucleophosmin and upstream binding factor-1 (UBF-1), involved in ribosomal RNA (rRNA) synthesis and cellular stress signalling. Interaction between aprataxin and nucleolin occurred through their respective N-terminal regions. In AOA1 cells lacking aprataxin, the stability of nucleolin was significantly reduced. On the other hand, down-regulation of nucleolin by RNA interference did not affect aprataxin protein levels but abolished its nucleolar localization suggesting that the interaction with nucleolin is involved in its nucleolar targeting. GFP-aprataxin fusion protein co-localized with nucleolin, nucleophosmin and UBF-1 in nucleoli and inhibition of ribosomal DNA transcription altered the distribution of aprataxin in the nucleolus, suggesting that the nature of the nucleolar localization of aprataxin is also dependent on ongoing rRNA synthesis. In vivo rRNA synthesis analysis showed only a minor decrease in AOA1 cells when compared with controls cells. These results demonstrate a cross-dependence between aprataxin and nucleolin in the nucleolus and while aprataxin does not appear to be directly involved in rRNA synthesis its nucleolar localization is dependent on this synthesis.

Textilinin-1 (Txln-1), a Kunitz-type serine protease inhibitor, is a 59-amino-acid polypeptide isolated from the venom of the Australian Common Brown snake Pseudonaja textilis textilis. This molecule has been suggested as an alternative to aprotinin, also a Kunitz-type serine protease inhibitor, for use as an anti-bleeding agent in surgical procedures. Txln-1 shares only 47% amino-acid identity to aprotinin; however, six cysteine residues in the two peptides are in conserved locations. It is therefore expected that the overall fold of these molecules is similar but that they have contrasting surface features. Here, the crystallization of recombinant textilinin-1 (rTxln-1) as the free molecule and in complex with bovine trypsin (229 amino acids) is reported. Two organic solvents, phenol and 1,4-butanediol, were used as additives to facilitate the crystallization of free rTxln-1. Crystals of the rTxln-1-bovine trypsin complex diffracted to 2.0 angstroms resolution, while crystals of free rTxln-1 diffracted to 1.63 angstroms resolution.

A number of proteins are activated by stress stimuli but none so spectacularly or with the degree of complexity as the tumour suppressor p53 (human p53 gene or protein). Once stabilized, p53 is responsible for the transcriptional activation of a series of proteins involved in cell cycle control, apoptosis and senescence. This protein is present at low levels in resting cells but after exposure to DNA-damaging agents and other stress stimuli it is stabilized and activated by a series of post-translational modifications that free it from MDM2 (mouse double minute 2 but used interchangeably to denote human also), a ubiquination ligase that ubiquitinates it prior to proteasome degradation. The stability of p53 is also influenced by a series of other interacting proteins. In this review, we discuss the post-translational modifications to p53 in response to different stresses and the consequences of these changes.

Ataxia-telangiectasia mutated (ATM), the protein defective in ataxia-telangiectasia, plays a central role in DNA damage response and signaling to cell cycle checkpoints. We describe here a cell line from a patient with an ataxia-telangiectasia–like clinical phenotype defective in the p53 response to radiation but with normal ATM activation and efficient downstream phosphorylation of other ATM substrates. No mutations were detected in ATM cDNA. A normal level of interaction between p53 and peptidyl-prolyl-isomerase Pin1 suggests that posttranslational modification was intact in these cells but operating at reduced level. Defective p53 stabilization was accompanied by defective induction of p53 effector genes and failure to induce apoptosis in response to DNA-damaging agents. Continued association between p53 and murine double minute-2 (Mdm2) occurred in irradiated ATL2ABR cells in response to DNA damage, and incubation with Mdm2 antagonists, nutlins, increased the stabilization of p53 and its transcriptional activity but failed to induce apoptosis. These results suggest that ATM-dependent stabilization of p53 and induction of apoptosis by radiation involve an additional factor(s) that is defective in ATL2ABR cells. (Cancer Res 2006; 66(6): 2907-12)

Venom from the Australian elapid Pseudonaja textilis (Common or Eastern Brown snake), is the second most toxic snake venom known and is the most common cause of death from snake bite in Australia. This venom is known to contain a prothrombin activator complex, serine proteinase inhibitors, various phospholipase A2s, and pre- and postsynaptic neurotoxins. In this study, we performed a proteomic identification of the venom using two-dimensional gel electrophoresis, mass spectrometry, and de novo peptide sequencing. We identified most of the venom proteins including proteins previously not known to be present in the venom. In addition, we used immunoblotting and post-translational modification-specific enzyme stains and antibodies that reveal the complexity and regional diversity of the venom. Modifications observed include phosphorylation, gamma-carboxylation, and glycosylation. Glycoproteins were further characterized by enzymatic deglycosylation and by lectin binding specificity. The venom contains an abundance of glycoproteins with N-linked sugars that include glucose/mannose, N-acetylgalactosamine, N-acetylglucosamine, and sialic acids. Additionally there are multiple isoforms of mammalian coagulation factors that comprise a significant proportion of the venom. Indeed two of the identified proteins, a procoagulant and a plasmin inhibitor, are currently in development as human therapeutic agents.

The 2005 International Workshop on Ataxia‐Telangiectasia, ATM and the DNA Damage Response took place between 8 and 11 June 2005 on the banks of Lake Maggiore, Italy. The workshop was organized by L. Chessa and D. Delia. ![][1] This workshop on ataxia‐telangiectasia marked the tenth anniversary of the discovery of the gene that is defective in this syndrome—that is, ataxia‐telangiectasia mutated ( ATM ; Savitsky et al , 1995). At the meeting, several important developments were reported, including: an expansion of the substrate repertoire of the ATM kinase; the use of animal models to analyse the signalling pathways controlled by ATM and the functional consequences of disrupting these pathways; new insights into cell‐cycle control and the maintenance of genome stability; the influence of modifier genes on ATM function; and approaches for correcting the progressive neurodegeneration that is a part of this syndrome. Ataxia‐telangiectasia is an autosomal recessive disorder characterized by neurodegeneration, immunodeficiency, hypogonadism and susceptibility to cancer. At the cellular level, it is marked by genomic instability, which is due to a defective response to double‐stranded breaks (DSBs) in DNA. This is manifested by hypersensitivity to ionizing radiation (IR) and radiomimetic compounds, and by a decreased ability to activate the DNA‐damage‐response network, which includes the cell‐cycle checkpoints (Lavin & Shiloh, 1997; Chun & Gatti, 2004). The protein product of the ATM gene is present in the nucleus as an inactive dimer or oligomer, and is activated in response to DSBs in a process that involves autophosphorylation on serine (Ser) 1,981. This causes a dissociation of the dimer to form active monomeric forms, which are able to initiate the phosphorylation of many intermediates, such as p53 and the checkpoint kinase Chk2, which are involved in DNA repair and cell‐cycle control (Bakkenist & Kastan, 2003). However, ATM is not solely responsible for initiating this … [1]: /embed/graphic-1.gif

Cells respond to genotoxic insults such as ionizing radiation by halting in the G2 phase of the cell cycle. Delayed cell death (mitotic death) can occur when the cell is released from G2, and specific spindle defects form endopolyploid cells (endoreduplication/tetraploidy). Enhanced G2 chromosomal radiosensitivity has been observed in many cancers and genomic instability syndromes, and it is manifested by radiation-induced chromatid aberrations observed in lymphocytes of patients. Here we compare the G2 chromosomal radiosensitivity in prostate patients with benign prostatic hyperplasia (BPH) or prostate cancer with disease-free controls. We also investigated whether there is a correlation between G2 chromosomal radiosensitivity and aneuploidy (tetraploidy and endoreduplication), which are indicative of mitotic cell death. The G2 assay was carried out on all human blood samples. Metaphase analysis was conducted on the harvested chromosomes by counting the number of aberrations and the mitotic errors (endoreduplication/tetraploidy) separately per 100 metaphases. A total of 1/14 of the controls were radiosensitive in G2 compared to 6/15 of the BPH patients and 15/17 of the prostate cancer patients. Radiation-induced mitotic inhibition was assessed to determine the efficacy of G2 checkpoint control in the prostate patients. There was no significant correlation of G2 radiosensitivity scores and mitotic inhibition in BPH patients (P = 0.057), in contrast to prostate cancer patients, who showed a small but significant positive correlation (P = 0.029). Furthermore, there was no significant correlation between G2 radiosensitivity scores of BPH patients and endoreduplication/ tetraploidy (P = 0.136), which contrasted with an extremely significant correlation observed in prostate cancer patients (P0.0001). In conclusion, cells from prostate cancer patients show increased sensitivity to the induction of G2 aberrations from ionizing radiation exposure but paradoxically show reduced mitotic indices and aneuploidy as a function of aberration frequency.

Australian terrestrial elapid snakes contain amongst the most potently toxic venoms known. However, despite the well-documented clinical effects of snake bite, little research has focussed on individual venom components at the molecular level. To further characterise the components of Australian elapid venoms, a complementary (cDNA) microarray was produced from the venom gland of the coastal taipan (Oxyuranus scutellatus) and subsequently screened for venom gland-specific transcripts. A number of putative toxin genes were identified, including neurotoxins, phospholipases, a pseudechetoxin-like gene, a venom natriuretic peptide and a nerve growth factor together with other genes involved in cellular maintenance. Venom gland-specific components also included a calglandulin-like protein implicated in the secretion of toxins from the gland into the venom. These toxin transcripts were subsequently identified in seven other related snake species, producing a detailed comparative analysis at the cDNA and protein levels. This study represents the most detailed description to date of the cloning and characterisation of different genes associated with envenomation from Australian snakes.

The snake venom group C prothrombin activators contain a number of components that enhance the rate of prothrombin activation. The cloning and expression of full-length cDNA for one of these components, an activated factor X (factor Xa)-like protease from Pseudonaja textilis as well as the generation of functional chimeric constructs with procoagulant activity were described. The complete cDNA codes for a propeptide, light chain, activation peptide (AP) and heavy chain related in sequence to mammalian factor X. Efficient expression of the protease was achieved with constructs where the AP was deleted and the cleavage sites between the heavy and light chains modified, or where the AP was replaced with a peptide involved in insulin receptor processing. In human kidney cells (H293F) transfected with these constructs, up to 80% of the pro-form was processed to heavy and light chains. Binding of the protease to barium citrate and use of specific antibodies demonstrated that gamma-carboxylation of glutamic acid residues had occurred on the light chain in both cases, as observed in human factor Xa and the native P. textilis protease. The recombinant protease caused efficient coagulation of whole citrated blood and citrated plasma that was enhanced by the presence of Ca2+. This study identified the complete cDNA sequence of a factor Xa-like protease from P. textilis and demonstrated for the first time the expression of a recombinant form of P. textilis protease capable of blood coagulation.

To study the dynamics of protein recruitment to DNA lesions, ion beams can be used to generate extremely localized DNA damage within restricted regions of the nuclei. This inhomogeneous spatial distribution of lesions can be visualized indirectly and rapidly in the form of radiation-induced foci using immunocytochemical detection or GFP-tagged DNA repair proteins. To analyze faster protein translocations and a possible contribution of radiation-induced chromatin movement in DNA damage recognition in live cells, we developed a remote-controlled system to obtain high-resolution fluorescence images of living cells during ion irradiation with a frame rate of the order of seconds. Using scratch replication labeling, only minor chromatin movement at sites of ion traversal was observed within the first few minutes of impact. Furthermore, time-lapse images of the GFP-coupled DNA repair protein aprataxin revealed accumulations within seconds at sites of ion hits, indicating a very fast recruitment to damaged sites. Repositioning of the irradiated cells after fixation allowed the comparison of live cell observation with immunocytochemical staining and retrospective etching of ion tracks. These results demonstrate that heavy-ion radiation-induced changes in subnuclear structures can be used to determine the kinetics of early protein recruitment in living cells and that the changes are not dependent on large-scale chromatin movement at short times postirradiation.

Treatment with the protein kinase C activator 12-O tetradecanoylphorbol 12-acetate (TPA) enables radiation-resistant LNCaP human prostate cancer cells to undergo radiation-induced apoptosis, mediated via activation of the enzyme ceramide synthase (CS) and de novo synthesis of the sphingolipid ceramide (Garzotto, M., Haimovitz-Friedman, A., Liao, W. C., White-Jones, M., Huryk, R., Heston, D. W. W., Cardon-Cardo, C., Kolesnick, R., and Fuks, Z. (1999) Cancer Res. 59, 5194-5201). Here, we show that TPA functions to decrease the cellular level of the ATM (ataxia telangiectasia mutated) protein, known to repress CS activation (Liao, W.-C., Haimovitz-Friedman, A., Persaud, R., McLoughlin, M., Ehleiter, D., Zhang, N., Gatei, M., Lavin, M., Kolesnick, R., and Fuks, Z. (1999) J. Biol. Chem. 274, 17908-17917). Gel shift analysis in LNCaP and CWR22-Rv1 cells demonstrated a significant reduction in DNA binding of the Sp1 transcription factor to the ATM promoter, and quantitative reverse transcription-PCR showed a 50% reduction of ATM mRNA between 8 and 16 h of TPA treatment, indicating that TPA inhibits ATM transcription. Furthermore, treatment of LNCaP, CWR22-Rv1, PC-3, and DU-145 human prostate cells with antisense-ATM oligonucleotides, which markedly reduced cellular ATM levels, significantly enhanced radiation-induced CS activation and apoptosis, leading to apoptosis at doses as a low as 1 gray. These data suggest that the CS pathway initiates a generic mode of radiation-induced apoptosis in human prostate cancer cells, regulated by a suppressive function of ATM, and that ATM might represent a potential target for pharmacologic inactivation with potential clinical applications in human prostate cancer.

While ATM, the protein defective in the human genetic disorder ataxia-telangiectasia (A-T), is primarily activated as a preexisting protein by radiation, there is also evidence that expression of the protein can be regulated at the transcriptional level. Activation of the ATM promoter by ionizing radiation has been reported only in quiescent cells in culture. To investigate how the Atm promoter is regulated in vivo, we generated transgenic mice that express the luciferase reporter gene under the control of the murine Atm promoter. Using a biophotonic imaging system luciferase activity was monitored in vivo. Strong promoter activity was detected throughout the transgenic animals with particularly high signals from the thymus, abdominal region, and reproductive organs. This activity further increased in response to both ionizing radiation and heat stress in a time dependent manner. Luciferase activity, measured in vitro in extracts from different tissues, showed highest activities in testes, ovaries, and cerebellum. Subjecting these mice to a single dose of 4 Gy total body radiation led to a time-dependent activation of the promoter with the strongest response observed in the peritoneal membrane, skin, and spleen. For most tissues tested, maximal promoter activity was reached 8 hr after radiation. The observed changes in promoter activity largely correlated with levels and activity of Atm protein in tissue extracts. These results demonstrate that, in addition to activation by autophosphorylation, Atm can also be regulated in vivo at the transcriptional level possibly ensuring a more sustained response to radiation and other stimuli. (c) 2005 Wiley-Liss, Inc.

Reading of the genetic code through nonsense mutations to restore protein function is a concept that dates back 50 years, with the discovery that streptomycin was capable of correcting defective genotypes.1 In the intervening years, suppression of premature termination codons (PTCs) by aminoglycoside antibiotics and other compounds has been employed to express full-length normal protein in a range of disease states. This approach has met with success in restoring at least partial function, and several of these compounds are at an advanced stage in clinical trials. Important targets include genes encoding the cystic fibrosis (CF) fibrosis transmembrane conductance regulator (CFTR) and dystrophin, which is defective in the X-linked neuromuscular disorder Duchenne muscular dystrophy. However, this approach can be applied to many less common genetic disorders caused by nonsense mutations that lead to premature truncation of a protein.2 In this issue, Du et al. build on previous efforts using high-throughput screening of small-molecule libraries to identify novel readthrough compounds (RTCs) that suppress all three stop codons (TGA, TAG, and TAA) in ataxia telangiectasia mutated (ATM), which is defective in the human genetic disorder ataxia telangiectasia (A-T).3 The authors refer to these as small-molecular readthrough (SMRT) compounds and reveal that they have structures that are quite different from those of two previously described compounds (RTC 13 and RTC 14)4 but are comparable or superior to them in efficiency in their readthrough capacity for ATM. Although successful treatment of this rare genetic disorder is unlikely to have a major impact on community health, the authors point to a “one drug fits all” model that would have broad translational potential for several other disorders.

Mutations in components of the Mre11/Rad50/Nbs1 complex give rise to genetic disorders characterized by neurological abnormalities, radiosensitivity, cell cycle checkpoint defects, genomic instability and cancer predisposition. Evidence exists that this complex associates with chromatin during DNA replication and acts as a sensor of double strand breaks (dsbs) in DNA after exposure to radiation. A series of recent reports provides additional support that the complex senses breaks in DNA and relays this information to ATM, mutated in ataxia-telangiectasia (A-T), which in turn activates pathways for cell cycle checkpoint activation. Paradoxically members of the Mre11 complex are also downstream of ATM in these pathways. Here, Lavin attempts to make sense of this sensing mechanism with reference to a series of recent reports on the topic.

Serine/threonine protein kinase AMP-activated protein kinase (AMPK) is a key metabolic stress-responsive factor that promotes the adaptation of cells to their microenvironment. Elevated concentrations of intracellular AMP, caused by metabolic stress, are known to activate AMPK by phosphorylation of the catalytic subunit. Recently, the tumor suppressor serine/threonine protein kinase LKB1 was identified as an upstream kinases, AMPKKs. In the current study, we found that stimulation with growth factors also caused AMPK-alpha subunit phosphorylation. Interestingly, even an LKB1-nonexpressing cancer cell line, HeLa, exhibited growth factor-stimulated AMPK-alpha subunit phosphorylation, suggesting the presence of an LKB1-independent pathway for AMPK-alpha subunit phosphorylation. In the human pancreatic cancer cell line PANC-1, AMPK-alpha subunit phosphorylation promoted by IGF-1 was suppressed by antisense ataxia telangiectasia mutated (ATM) expression. We found that IGF-1 also induced AMPK-alpha subunit phosphorylation in the human normal fibroblast TIG103 cell line, but failed to do so in a human fibroblast AT2-KY cell line lacking ATM. Immunoprecipitates of ATM collected from IGF-1-stimulated cells also caused the phosphorylation of the AMPK-alpha subunit in vitro. IGF-1-stimulated ATM phosphorylation at both threonine and tyrosine residues, and our results demonstrated that the phosphorylation of tyrosine in the ATM molecule is important for AMPK-alpha subunit phosphorylation during IGF-1 signaling. These results suggest that IGF-1 induces AMPK-alpha subunit phosphorylation via an ATM-dependent and LKB1-independent pathway.

The product of the gene (ATM) mutated in the human genetic disorder ataxia-telangiectasia (A-T) is a high molecular weight, protein ( approximately 350kDa) containing a C-terminal protein kinase domain and a number of other putative domains not yet functionally defined. The majority of ATM gene mutations in A-T patients are truncating, resulting in prematurely terminated products that are highly unstable. Missense mutations within the kinase domain and elsewhere in the molecule alter the stability of the protein and lead to loss of protein kinase activity. Only rarely are patients observed with two missense mutations and this gives rise to a milder disease phenotype. Evidence for a dominant interfering effect on normal ATM kinase activity has been reported in cell lines transfected with missense mutant ATM and in cell lines from some A-T heterozygotes. The dominant negative effect of mutant ATM is manifested by an enhancement of cellular radiosensitivity and may be responsible for the cancer predisposition observed in carriers of ATM missense mutations. In this review, we explore the domain structure of the ATM molecule, sites of interaction with other proteins and the consequences of specific amino acid changes on function.