Novel dimeric structure of phage ϕ29-encoded protein p56: insights into uracil-DNA glycosylase inhibition

Protein p56 encoded by the Bacillus subtilis phage ϕ29 inhibits the host uracil-DNA glycosylase (UDG) activity. To get insights into the structural basis for this inhibition, the NMR solution structure of p56 has been determined. The inhibitor defines a novel dimeric fold, stabilized by a combination of polar and extensive hydrophobic interactions. Each polypeptide chain contains three stretches of anti-parallel β-sheets and a helical region linked by three short loops. In addition, microcalorimetry titration experiments showed that it forms a tight 2:1 complex with UDG, strongly suggesting that the dimer represents the functional form of the inhibitor. This was further confirmed by the functional analysis of p56 mutants unable to assemble into dimers. We have also shown that the highly anionic region of the inhibitor plays a significant role in the inhibition of UDG. Thus, based on these findings and taking into account previous results that revealed similarities between the association mode of p56 and the phage PBS-1/PBS-2-encoded inhibitor Ugi with UDG, we propose that protein p56 might inhibit the enzyme by mimicking its DNA substrate

Antitumor activity of the novel multi-kinase inhibitor EC-70124 in triple negative breast cancer

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.Disseminated triple negative breast cancer (TNBC) is an incurable disease with limited therapeutic options beyond chemotherapy. Therefore, identification of druggable vulnerabilities is an important aim. Protein kinases play a central role in cancer and particularly in TNBC. They are involved in many oncogenic functions including migration, proliferation, genetic stability or maintenance of stem-cell like properties. In this article we describe a novel multi-kinase inhibitor with antitumor activity in this cancer subtype. EC-70124 is a hybrid indolocarbazole analog obtained by combinatorial biosynthesis of Rebeccamycin and Staurosporine genes that showed antiproliferative effect and in vivo antitumoral activity. Biochemical experiments demonstrated the inhibition of the PI3K/mTOR and JAK/STAT pathways. EC-70124 mediated DNA damage leading to cell cycle arrest at the G2/M phase. Pathway analyses identified several deregulated functions including cell proliferation, migration, DNA damage, regulation of stem cell differentiation and reversion of the epithelial-mesenchymal transition (EMT) phenotype, among others. Combination studies showed a synergistic interaction of EC-70124 with docetaxel, and an enhanced activity in vivo. Furthermore, EC-70124 had a good pharmacokinetic profile. In conclusion these experiments demonstrate the antitumor activity of EC-70124 in TNBC paving the way for the future clinical development of this drug alone or in combination with chemotherapy.Ministry of Economy and Competitiveness of Spain (BFU2012-39151 and RD12/0036/0003 to AP), and the AECC (to AP). Instituto de Salud Carlos III (PI13/01444) ACEPAIN and CRIS Cancer Foundation (to AO). JCM is a recipient of a Miguel Servet fellowship program (CP12/03073).Peer Reviewe

Propranolol reduces viability and induces apoptosis in hemangioblastoma cells from von Hippel-Lindau patients

[Background] Von Hippel-Lindau (VHL) disease is a rare oncological disease with an incidence of 1:36,000, and is characterized by the growth of different types of tumors: hemangioblastomas in the central nervous system (CNS) and retina, renal carcinoma, pheochromocytomas, pancreatic serous cystadenoma, and endolymphatic sac tumors. These tumors do not express VHL protein (pVHL). pVHL ubiquitinates hypoxia inducible factor (HIF) protein for degradation by the proteasome; in the absence of VHL, HIF translocates to the nucleus to activate the expression of its target genes. Targeting VHL-derived tumors with drugs that have reduced side effects is urgent to avoid repeat CNS surgeries. Recent reports have shown that propranolol, a β-blocker used for the treatment of hypertension and other cardiac and neurological diseases, is the best option for infantile hemangioma (IH). Propranolol could be an efficient treatment to control hemangioblastoma growth in VHL disease because of its antiangiogenic effects demonstrated in IH and the hypothetical impact on HIF levels.[Methods] HeLa 9X (HRE) hypoxia responsive element cell line and primary hemangioblastoma-derived cells were subjected to propranolol treatment and cell viability and apoptosis were evaluated. HIF1-α and Hif-2α expression after propranolol treatment was analyzed by western blotting. Quantitative PCR was performed to study the mRNA expression of HIF target genes. Vascular endothelial growth factor (VEGF) was measured in culture supernatants by immunoassay.[Results] Propranolol downregulated HIF-dependent transcription in HeLa 9XHRE cells. Under hypoxic conditions, propranolol decreased the expression of HIF target genes in hemangioblastoma cells, which stopped proliferating and died following long-term treatment. These results suggests that propranolol treatment promoted reduced HIF protein expression and corresponding downregulation of HIF target genes, and inhibited cell proliferation in parallel with induction of cell death by apoptosis.[Conclusions] Our results suggest that propranolol could reduce the growth of HIF-dependent tumors and may thus be a promising treatment to delay surgery in VHL patients.This work was supported by grants from Ministerio de Economia y Competitividad SAF2011-23475 and from Alianza VHL Spain& Fundación Iberdrola to LMB. Virginia Albiñana was supported by Alianza VHL Spain, Fundación Iberdrola and Fundación Divina Pastora.Peer reviewe

Role of retinal pigment epithelium-derived exosomes and autophagy in new blood vessel formation

Autophagy and exosome secretion play important roles in a variety of physiological and disease states, including the development of age‐related macular degeneration. Previous studies have demonstrated that these cellular mechanisms share common pathways of activation. Low oxidative damage in ARPE‐19 cells, alters both autophagy and exosome biogenesis. Moreover, oxidative stress modifies the protein and genetic cargo of exosomes, possibly affecting the fate of surrounding cells. In order to understand the connection between these two mechanisms and their impact on angiogenesis, stressed ARPE‐19 cells were treated with a siRNA‐targeting Atg7, a key protein for the formation of autophagosomes. Subsequently, we observed the formation of multivesicular bodies and the release of exosomes. Released exosomes contained VEGFR2 as part of their cargo. This receptor for VEGF—which is critical for the development of new blood vessels—was higher in exosome populations released from stressed ARPE‐19. While stressed exosomes enhanced tube formation, exosomes became ineffective after silencing VEGFR2 in ARPE‐19 cells and were, consequently, unable to influence angiogenesis. Moreover, vessel sprouting in the presence of stressed exosomes seems to follow a VEGF‐independent pathway. We propose that abnormal vessel growth correlates with VEGFR2‐expressing exosomes release from stressed ARPE‐19 cells, and is directly linked to autophagy

Circulating DNA and survival in solid tumors

[Background]: The ability to undertake molecular analysis to inform on prognosis and predictors of response to therapy is limited by accessibility of tissue. Measurement of total circulating free DNA (cfDNA) or circulating tumor DNA (ctDNA) in peripheral blood may allow easier access to tumor material and help to predict clinical outcomes. [Methods]: A systematic review of electronic databases identified publications exploring the association between cfDNA or ctDNA and overall survival (OS) in solid tumors. HRs for OS were extracted from multivariable analyses and included in a meta-analysis. Pooled HRs were computed and weighted using generic inverse variance and random-effect modeling. For studies not reporting multivariable analyses, univariable ORs were estimated from Kaplan-Meier curves for OS at 1 and 3 years. [Results]: Thirty-nine studies comprising 4,052 patients were included in the analysis. Detection of ctDNA was associated with a significantly worse OS in multivariable analyses [HR, 2.70; 95% confidence interval (CI), 2.02-3.61; P < 0.001). Similar results were observed in the univariable analyses at 3 and 1 year (OR, 4.83; 95% CI, 3.20-7.28; P < 0.001).There was also a statistically significant association between high total cfDNA and worse OS for studies reporting multivariable and univariate data at 3 years (HR, 1.91; 95% CI, 1.59-2.29; P < 0.001 and OR, 2.82; 95% CI, 1.93-4.13; P < 0.001, respectively). [Conclusions]: High levels of total cfDNA and presence of ctDNA are associated with worse survival in solid tumors. [Impact]: Circulating DNA is associated with worse outcome in solid tumors.This work was supported by grants from CRIS cancer foundation (to A. Ocaña and A. Pandiella).Peer Reviewe

TRAF3 Epigenetic Regulation Is Associated With Vascular Recurrence in Patients With Ischemic Stroke

Clopidogrel is one of the most used antiplatelet drugs in patients with cardiovascular disease. However, 16% to 50% of patients have a high on-clopidogrel platelet reactivity and an increased risk of ischemic events. The pathogenesis of high on-treatment platelet reactivity in patients with stroke is only partially explained by genetic variations. This study aims to find differentially methylated sites across the genome associated with vascular recurrence in ischemic stroke patients treated with clopidogrel

El cáncer hereditario en mujeres

Most cases of cancer are sporadic, whereas 5-10% are hereditary and about 20-30% of cancers tend to cluster in families. Families and individuals who are suspected of suffering from hereditary cancer need to undergo a process known as genetic counseling, which is of considerable importance in the prevention and early detection of malignant tumours. The most common hereditary cancer syndromes are: hereditary breast-ovarian cancer syndrome, familial adenomatous polyposis and Lynch syndrome. Genetic diagnosis allows clinicians to estimate the risks of developing different cancers in order to make decisions over surveillance and prophylactic surgery to reduce these risks. The ultimate goal is to reduce cancer mortality through early diagnosis and prevention.La mayoría de los casos de cáncer son esporádicos, entre un 20-30% presentan agregación familiar, mientras que solo el 5 -10% son de carácter hereditario. Las familias e individuos en los que se sospecha que padecen cáncer hereditario deben someterse a un proceso de asesoramiento genético, que es de gran importancia para la prevención y detección temprana de tumores malignos. Los síndromes más frecuentes de cáncer hereditario son el síndrome de mama-ovario hereditario, la poliposis adenomatosa familiar y el síndrome de Lynch. El diagnóstico genético facilita realizar una estimación de los riesgos de desarrollar diferentes cánceres, permitiendo tomar decisiones de vigilancia y preventivas que reducen estos riesgos. El objetivo final es reducir la mortalidad por cáncer mediante el diagnóstico precoz y la prevención

Hereditary Cancer In Women

[spa] La mayoría de los casos de cáncer son esporádicos, entre un 20-30% presentan agregación familiar, mientras que solo el 5 -10% son de carácter hereditario. Las familias e individuos en los que se sospecha que padecen cáncer hereditario deben someterse a un proceso de asesoramiento genético, que es de gran importancia para la prevención y detección temprana de tumores malignos. Los síndromes más frecuentes de cáncer hereditario son el síndrome de mama-ovario hereditario, la poliposis adenomatosa familiar y el síndrome de Lynch. El diagnóstico genético facilita realizar una estimación de los riesgos de desarrollar diferentes cánceres, permitiendo tomar decisiones de vigilancia y preventivas que reducen estos riesgos. El objetivo final es reducir la mortalidad por cáncer mediante el diagnóstico precoz y la prevención.[eng] Most cases of cancer are sporadic, whereas 5-10% are hereditary and about 20-30% of cancers tend to cluster in families. Families and individuals who are suspected of suffering from hereditary cancer need to undergo a process known as genetic counseling, which is of considerable importance in the prevention and early detection of malignant tumours. The most common hereditary cancer syndromes are: hereditary breast-ovarian cancer syndrome, familial adenomatous polyposis and Lynch syndrome. Genetic diagnosis allows clinicians to estimate the risks of developing different cancers in order to make decisions over surveillance and prophylactic surgery to reduce these risks. The ultimate goal is to reduce cancer mortality through early diagnosis and prevention

A Multitrait Genetic Study of Hemostatic Factors and Hemorrhagic Transformation after Stroke Treatment

BACKGROUND: Thrombolytic recombinant tissue plasminogen activator (r-tPA) treatment is the only pharmacologic intervention available in the ischemic stroke acute phase. This treatment is associated with an increased risk of intracerebral hemorrhages, known as hemorrhagic transformations (HTs), which worsen the patient\u27s prognosis. OBJECTIVES: to investigate the association between genetically determined natural hemostatic factors\u27 levels and increased risk of HT after r-tPA treatment. METHODS: Using data from genome-wide association studies on the risk of HT after r-tPA treatment and data on 7 hemostatic factors (factor [F]VII, FVIII, von Willebrand factor [VWF], FXI, fibrinogen, plasminogen activator inhibitor-1, and tissue plasminogen activator), we performed local and global genetic correlation estimation multitrait analyses and colocalization and 2-sample Mendelian randomization analyses between hemostatic factors and HT. RESULTS: Local correlations identified a genomic region on chromosome 16 with shared covariance: fibrinogen-HT, P = 2.45 × 10 CONCLUSION: We identified 4 shared loci between hemostatic factors and HT after r-tPA treatment, suggesting common regulatory mechanisms between fibrinogen and VWF levels and HT. Further research to determine a possible mediating effect of fibrinogen on HT risk is needed

Single nucleotide variations in ZBTB46 are associated with post-thrombolytic parenchymal haematoma

Haemorrhagic transformation is a complication of recombinant tissue-plasminogen activator treatment. The most severe form, parenchymal haematoma, can result in neurological deterioration, disability, and death. Our objective was to identify single nucleotide variations associated with a risk of parenchymal haematoma following thrombolytic therapy in patients with acute ischaemic stroke. A fixed-effect genome-wide meta-analysis was performed combining two-stage genome-wide association studies (n = 1904). The discovery stage (three cohorts) comprised 1324 ischaemic stroke individuals, 5.4% of whom had a parenchymal haematoma. Genetic variants yielding a P-value < 0.05 1 x 10(-5) were analysed in the validation stage (six cohorts), formed by 580 ischaemic stroke patients with 12.1% haemorrhagic events. All participants received recombinant tissue-plasminogen activator; cases were parenchymal haematoma type 1 or 2 as defined by the European Cooperative Acute Stroke Study (ECASS) criteria. Genome-wide significant findings (P < 5 x 10(-8)) were characterized by in silica functional annotation, gene expression, and DNA regulatory elements. We analysed 7 989 272 single nucleotide polymorphisms and identified a genome-wide association locus on chromosome 20 in the discovery cohort; functional annotation indicated that the ZBTB46 gene was driving the association for chromosome 20. The top single nucleotide polymorphism was rs76484331 in the ZBTB46 gene [P = 2.49 x 10(-8); odds ratio (OR): 11.21; 95% confidence interval (CI): 4.82-26.55]. In the replication cohort (n = 580), the rs76484331 polymorphism was associated with parenchymal haematoma (P = 0.01), and the overall association after meta-analysis increased (P = 1.61 x 10(-8), OR: 5.84; 95% CI: 3.16-10.76). ZBTB46 codes the zinc finger and BTB domain-containing protein 46 that acts as a transcription factor. In silica studies indicated that ZBTB46 is expressed in brain tissue by neurons and endothelial cells. Moreover, rs76484331 interacts with the promoter sites located at 20q13. In conclusion, we identified single nucleotide variants in the ZBTB46 gene associated with a higher risk of parenchymal haematoma following recombinant tissue-plasminogen activator treatment.Peer reviewe