Explore the vast range of titles available.

GATA3 is thought to be a critical checkpoint in allergic diathesis. In this study, a synthetic DNAzyme that catalyzes the inactivation of GATA3 when administered by inhalation attenuated the late asthmatic response in laboratory challenges. Asthma is a common chronic inflammatory disease of the airways that is characterized by variable airway obstruction, hypersecretion of mucus, airway inflammation, and hyperresponsiveness of the airways. The dysregulation of innate and adaptive immune responses is considered to play a central role in the development of the disease. The high degree of interindividual heterogeneity identified in different patient populations has led to the definition of several clinical phenotypes and pathophysiological endotypes. 1 The allergic response driven by the type 2 helper T cell (Th2), 2 , 3 also termed the Th2 molecular endotype, is thought to be characteristic of allergic asthma. 4 , 5 Approximately . . .

The ability of the 10–23 DNAzyme to specifically cleave RNA with high efficiency has fuelled expectation that this agent may have useful applications for targeted therapy. Here, we, for the first time, investigated the antitumor and radiosensitizing effects of a DNAzyme (DZ1) targeted to the Epstein-Barr virus (EBV)-LMP1 mRNA of nasopharyngeal carcinoma (NPC) in patients. Preclinical studies indicated that the DNAzyme was safe and well tolerated. A randomized and double-blind clinical study was conducted in 40 NPC patients who received DZ1 or saline intratumorally, in conjunction with radiation therapy. Tumor regression, patient survival, EBV DNA copy number and tumor microvascular permeability were assessed in a 3-month follow-up. The mean tumor regression rate at week 12 was significantly higher in DZ1 treated group than in the saline control group. Molecular imaging analysis showed that DZ1 impacted on tumor microvascular permeability as evidenced by a faster decline of the Ktrans in DZ1-treated patients. The percentage of the samples with undetectable level of EBV DNA copy in the DZ1 group was significantly higher than that in the control group. No adverse events that could be attributed to the DZ1 injection were observed in patients.

Background EBV-encoded latent membrane protein 1 (EBV-LMP1) is an important oncogenic protein for nasopharyngeal carcinoma (NPC) and has been shown to engage a plethora of signaling pathways. Correspondingly, an LMP1-targeted DNAzyme was found to inhibit the growth of NPC cells both in vivo and in vitro by suppressing cell proliferation and inducing apoptosis. However, it remains unknown whether an LMP1-targeted DNAzyme would affect the vasculature of NPC. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been applied in the clinical trials of anti-angiogenic drugs for more than ten years, and K trans has been recommended as a primary endpoint. Therefore, the objective of the current study was to use DCE-MRI to longitudinally study the effect of an EBV-LMP1-targeted DNAzyme on the vasculature of patients with NPC. Methods Twenty-four patients were randomly divided into two groups: a combined treatment group (radiotherapy + LMP1-targeted DNAzyme) and a radiotherapy alone group (radiotherapy + normal saline). DCE-MRI scans were conducted 1 ~ 2 days before radiotherapy (Pre-RT), during radiotherapy (RT 50 Gy), upon completion of radiotherapy (RT 70 Gy), and three months after radiotherapy (3 months post-RT). Parameters of vascular permeability and intra- and extravascular volumes were subsequently obtained (e.g., K trans , k ep , v e ) using nordicICE software. Results Both K trans and k ep values for NPC tumor tissues decreased for both groups after treatment. Moreover, a statistically significant difference in K trans values at the pre-therapy and post-therapy timepoints emerged earlier for the combined treatment group (RT 50 Gy, P =0.045) compared to the radiotherapy alone group (3 months post-RT, P = 0.032). For the k ep values, the downward trend observed for both the combined treatment group and the radiotherapy alone group were similar. In contrast, v e values for all of the tumor tissues increased following therapy. Conclusions The EBV-LMP1-targeted DNAzyme that was tested was found to accelerate the decline of K trans values for patients with NPC. Correspondingly, the LMP1-targeted DNAzyme treatments were found to affect the angiogenesis and microvascular permeability of NPC. Trial registration ClinicalTrials.gov: NCT01449942 . Registered 6 October 2011.

The nuclear transcription factor c-Jun is preferentially expressed in basal-cell carcinoma. Dz13 is a deoxyribozyme that targets JUN messenger RNA and has inhibited the growth of a range of tumours in mice. We did a phase 1 study to assess safety and tolerability in human beings. Adults with nodular basal-cell carcinoma were recruited from Royal Prince Alfred Hospital, Sydney, Australia, between September, 2010, and October, 2011. Patients were assigned to receive one intratumoral injected dose of 10, 30, or 100 μg Dz13, in a 50 μL volume of lipid carrier, and were assessed for adverse effects in the first 24 h then at 7, 14, and 28 days after injection. Treated tumours were surgically excised 14 days after injection and compared with the baseline biopsy samples for expression of c-Jun and tumorigenesis markers. Nine patients were recruited, of whom three received each dose of Dz13. All patients completed the study with no drug-related serious adverse events. No systemic Dz13 exposure was detected. c-Jun expression was reduced in the excised tumours of all nine (100%) patients, compared with baseline, and histological tumour depth had decreased in five (56%) of nine. Proportions of cells positive for caspases 3, 8, and 9 and P53 were increased, but those of cells positive for Bcl-2 and MMP-9 were decreased. Infiltration by inflammatory and immune cells was stimulated. Dz13 was safe and well tolerated after single intratumoral injections at all doses. Cancer Institute NSW, Cancer Council Australia, and National Health and Medical Research Council.

DNA double-strand breaks (DSB) are formed by various exogenous and endogenous factors and are repaired by homologous recombination and non-homologous end joining (NHEJ). DNA-dependent protein kinase (DNA-PK) is the principal enzyme for NHEJ. We explored the role and the underlying mechanism of cAMP signaling in the NHEJ repair of DSBs resulted from gamma ray irradiation to non-small cell lung cancer (NSLC) cells. Activated cAMP signaling by expression of an activated stimulatory GTP-binding protein or by pretreatment with isoproterenol and prostaglandin E2, delayed the repair of DSBs resulted from gamma ray irradiation, and the delaying effects depended on protein kinase A (PKA). Activated cAMP signaling suppressed XRCC4 and DNA ligase IV recruitment into DSB foci, and reduced phosphorylation at T2609 in DNA-PK catalytic subunit (DNA-PKcs) with a concomitant increase in phosphorylation at S2056 in PKA-dependent ways following gamma ray irradiation. cAMP signaling decreased phosphorylation of T2609 by protein phosphatase 2A-dependent inhibition of ATM. We conclude that cAMP signaling delays the repair of gamma ray-induced DNA DSBs in NSLC cells by inhibiting NHEJ via PKA-dependent pathways, and that cAMP signaling differentially modulates DNA-PKcs phosphorylation at S2056 and T2609, which might contribute to the inhibition of NHEJ in NSLC cells.

The development of HIV integrase (IN) strand transfer inhibitors (INSTIs) and our understanding of viral resistance to these molecules have been hampered by a paucity of available structural data. We recently reported cocrystal structures of the prototype foamy virus (PFV) intasome with raltegravir and elvitegravir, establishing the general INSTI binding mode. We now present an expanded set of cocrystal structures containing PFV intasomes complexed with first- and second-generation INSTIs at resolutions of up to 2.5 Å. Importantly, the improved resolution allowed us to refine the complete coordination spheres of the catalytic metal cations within the INSTI-bound intasome active site. We show that like the Q148H/G140S and N155H HIV-1 IN variants, the analogous S217H and N224H PFV INs display reduced sensitivity to raltegravir in vitro. Crystal structures of the mutant PFV intasomes in INSTI-free and -bound forms revealed that the amino acid substitutions necessitate considerable conformational rearrangements within the IN active site to accommodate an INSTI, thus explaining their adverse effects on raltegravir antiviral activity. Furthermore, our structures predict physical proximity and an interaction between HIV-1 IN mutant residues His148 and Ser/Ala140, rationalizing the coevolution of Q148H and G140S/A mutations in drug-resistant viral strains.

DNA polymerase ζ (pol ζ) plays a central role in replicating damaged genomic DNA. When DNA synthesis stalls at a lesion, it participates in translesion DNA synthesis (TLS), which helps replication proceed. TLS prevents cell death at the expense of new mutations. The current model indicates that pol ζ-dependent TLS events are mediated by Pol31/Pol32 pol ζ subunits, which are shared with replicative polymerase pol δ. Surprisingly, we found that the mutant rev3-ΔC in yeast, which lacks the C-terminal domain (CTD) of the catalytic subunit of pol ζ and, thus, the platform for interaction with Pol31/Pol32, retains most pol ζ functions. To understand the underlying mechanisms, we studied TLS in normal templates or templates with abasic sites in vitro in primer extension reactions with purified four-subunit pol ζ versus pol ζ with Rev3-ΔC. We also examined the specificity of ultraviolet radiation (UVR)-induced mutagenesis in the rev3-ΔC strains. We found that the absence of Rev3 CTD reduces activity levels, but does not alter the basic biochemical properties of pol ζ, and alters the mutation spectrum only at high doses of UVR, alluding to the existence of mechanisms of recruitment of pol ζ to UVR-damaged sites independent of the interaction of Pol31/Pol32 with the CTD of Rev3.

Bisphenol A (BPA) is an environmental endocrine disruptor which has been detected in human bodies. Many studies have implied that BPA exposure is harmful to human health. Previous studies mainly focused on BPA effects on estrogen receptor (ER)-positive cells. Genome-wide impacts of BPA on gene expression in ER-negative cells is unclear. In this study, we performed RNA-seq to characterize BPA-induced cellular and molecular impacts on ER-negative HEK293 cells. The microscopic observation showed that low-dose BPA exposure did not affect cell viability and morphology. Gene expression profiling analysis identified a list of differentially expressed genes in response to BPA exposure in HEK293 cells. These genes were involved in variable important biological processes including ion transport, cysteine metabolic process, apoptosis, DNA damage repair, etc. Notably, BPA up-regulated the expression of ERCC5 encoding a DNA endonuclease for nucleotide-excision repair. Further electrochemical experiment showed that BPA induced significant DNA damage in ER-positive MCF-7 cells but not in ER-negative HEK293 cells. Collectively, our study revealed that ER-negative HEK293 cells employed mechanisms in response to BPA exposure different from ER-positive cells.

Here, we have investigated the physical and molecular basis of stability of Arabidopsis DNA Pol λ, the sole X family DNA polymerase member in plant genome, under UV-B and salinity stress in connection with the function of the N-terminal BRCT (breast cancer-associated C terminus) domain and Ser-Pro rich region in the regulation of the overall structure of this protein. Tryptophan fluorescence studies, fluorescence quenching and Bis-ANS binding experiments using purified recombinant full length Pol λ and its N-terminal deletion forms have revealed UV-B induced conformational change in BRCT domain deficient Pol λ. On the other hand, the highly conserved C-terminal catalytic core PolX domain maintained its tertiary folds under similar condition. Circular dichroism (CD) and fourier transform infrared (FT-IR) spectral studies have indicated appreciable change in the secondary structural elements in UV-B exposed BRCT domain deficient Pol λ. Increased thermodynamic stability of the C-terminal catalytic core domain suggested destabilizing effect of the N-terminal Ser-Pro rich region on the protein structure. Urea-induced equilibrium unfolding studies have revealed increased stability of Pol λ and its N-terminal deletion mutants at high NaCl concentration. In vivo aggregation studies using transient expression systems in Arabidopsis and tobacco indicated possible aggregation of Pol λ lacking the BRCT domain. Immunoprecipitation assays revealed interaction of Pol λ with the eukaryotic molecular chaperone HSP90, suggesting the possibility of regulation of Pol λ stability by HSP90 in plant cell. Overall, our results have provided one of the first comprehensive information on the biophysical characteristics of Pol λ and indicated the importance of both BRCT and Ser-Pro rich modules in regulating the stability of this protein under genotoxic stress in plants.

Glutathione S-transferase P1 (GSTP1) is a critical enzyme in the phase II detoxification pathway. One of the common functional polymorphisms of GSTP1 is A→G at nucleotide 313, which results in an amino acid substitution (Ile105Val) at the substrate binding site and reduced catalytic activity. We evaluated the interaction between GSTP1 Val allele and Helicobacter pylori infection, smoking and alcohol consumption, increasing the risk of gastric cancer among the Chinese population. Information on potential gastric cancer risk factors and blood specimens were collected from 618 incident gastric cancer cases and 1,830 non-cancer controls between March 2002 and December 2011 in Liaoning Province, China. GSTP1 Ile105Val was genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and polymerase chain reaction-restriction fragment length polymorphism. Serum levels of anti-H. pylori IgG were measured by ELISA. Odds ratio (OR) and 95% confidence interval (CI) were calculated using multivariate logistic regression, adjusted by sex and age. The risk of gastric cancer was significantly elevated in patients with the GSTP1 Val/Val genotype (adjusted OR = 3.324; 95% CI = 1.790-6.172). An elevated risk of gastric cancer was observed in patients with H. pylori infection, smoking, or alcohol consumption, and together with the GSTP1 Ile/Val +Val/Val genotype (OR = 3.696; 95% CI = 2.475-5.521; OR = 1.638; 95% CI = 1.044-2.571; OR = 1.641; 95% CI = 0.983-2.739, respectively) (p<0.05). The GSTP1 Val allele shows an interaction with smoking, alcohol consumption, and especially H. pylori infection for increasing the risk of gastric cancer. These findings could demonstrate new pathophysiological pathways for the development of gastric cancer.