Space geodetic observations of nazca-south america convergence across the central andes

Space geodetic data recorded rates and directions of motion across the convergent boundary zone between the oceanic Nazca and continental South American plates in Peru and Bolivia. Roughly half of the overall convergence, about 30 to 40 millimeters per year, accumulated on the locked plate interface and can be released in future earthquakes. About 10 to 15 millimeters per year of crustal shortening occurred inland at the sub-Andean foreland fold and thrust belt, indicating that the Andes are continuing to build. Little (5 to 10 millimeters per year) along-trench motion of coastal forearc slivers was observed, despite the oblique convergence.

Slow deformation and lower seismic hazard at the new madrid seismic zone

Global Positioning System (GPS) measurements across the New Madrid seismic zone (NMSZ) in the central United States show little, if any, motion. These data are consistent with platewide continuous GPS data away from the NMSZ, which show no motion within uncertainties. Both these data and the frequency-magnitude relation for seismicity imply that had the largest shocks in the series of earthquakes that occurred in 1811 and 1812 been magnitude 8, their recurrence interval should well exceed 2500 years, longer than has been assumed. Alternatively, the largest 1811 and 1812 earthquakes and those in the paleoseismic record may have been much smaller than typically assumed. Hence, the hazard posed by great earthquakes in the NMSZ appears to be overestimated.

Fossilized high pressure from the Earth's deep interior: the coesite-in-diamond barometer

Mineral inclusions in diamonds provide an important source of information about the composition of the continental lithosphere at depths exceeding 120-150 km, i.e., within the diamond stability field. Fossilized high pressures in coesite inclusions from a Venezuela diamond have been identified and measured by using laser Raman and synchrotron x-ray microanalytical techniques. Micro-Raman measurements on an intact inclusion of remnant vibrational band shifts give a high confining pressure of 3.62 (+/-0.18) GPa. Synchrotron single-crystal diffraction measurements of the volume compression are in accord with the Raman results and also revealed direct structural information on the state of the inclusion. In contrast to olivine and garnet inclusions, the thermoelasticity of coesite favors accurate identification of pressure preservation. Owing to the unique combination of physical properties of coesite and diamond, this "coesite-in-diamond" geobarometer is virtually independent of temperature, allowing an estimation of the initial pressure of Venezuela diamond formation of 5.5 (+/-0.5) GPa.

MitoQ regulates autophagy by inducing a pseudo-mitochondrial membrane potential

During the process of oxidative phosphorylation, protons are pumped into the mitochondrial intermembrane space to establish a mitochondrial membrane potential (MMP). The electrochemical gradient generated allows protons to return to the matrix through the ATP synthase complex and generates ATP in the process. MitoQ is a lipophilic cationic drug that is adsorbed to the inner mitochondrial membrane; however, the cationic moiety of MitoQ remains in the intermembrane space. We found that the positive charges in MitoQ inhibited the activity of respiratory chain complexes I, III, and IV, reduced proton production, and decreased oxygen consumption. Therefore, a pseudo-MMP (PMMP) was formed via maintenance of exogenous positive charges. Proton backflow was severely impaired, leading to a decrease in ATP production and an increase in AMP production. Excess AMP activates AMP kinase, which inhibits the MTOR (mechanistic target of rapamycin) pathway and induces macroautophagy/autophagy. Therefore, we conclude that MitoQ increases PMMP via proton displacement with exogenous positive charges. In addition, PMMP triggered autophagy in hepatocellular carcinoma HepG2 cells via modification of mitochondrial bioenergetics pathways.

Use of on-line hydrogen/deuterium exchange to facilitate metabolite identification

Biotransformation studies performed on an investigational compound (I, represented by R1-CH(NH(2))-CO-N(R2)-CH(2)-S-R3) led to the identification of five metabolites (M1-M5). Based on LC/MS (liquid chromatography/mass spectrometry) analysis which included the use of H(2)O and D(2)O in the mobile phases, they were identified as the sulfoxide (M1), sulfone (M2), carbamoyl glucuronide (M3), N-glucuronide (M4), and N-glucoside (M5) metabolites, respectively. The structure of M3, a less commonly seen carbamoyl glucuronide metabolite, was established using on-line H/D (hydrogen/deuterium) exchange experiments conducted by LC/MS. H/D exchange experiments were also used to distinguish the S-oxidation structures of M1 and M2 from hydroxylation. Herein, the application of deuterium oxide as the LC/MS mobile phase for structural elucidation of drug metabolites in biological matrices is demonstrated.

A semi-automated method for measuring the potential for protein covalent binding in drug discovery

INTRODUCTION

Covalent protein binding of metabolically reactive intermediates of drugs has been implicated in drug toxicity including the occurrence of idiosyncratic drug toxicity. Investigators therefore would prefer to avoid developing compounds that produce significant amounts of reactive metabolites. By incubating the radiolabeled drug of interest with liver microsomes it is possible to evaluate the propensity of a drug candidate to covalently bind to proteins.

METHODS

Here we present a semi-automated method in which a Brandel cell harvester is used to collect and wash proteins that have been incubated with radiolabeled drug. This method utilizes glass fiber filter paper to capture precipitated protein, rather than the more traditional exhaustive extraction/centrifugation approach. Using model compounds (including [14C]diclofenac, [3H]imipramine, [14C]naphthalene, and [14C]L-746530) we compare the covalent binding results obtained using this method to results generated using the traditional method and we performed cross-laboratory testing of assay reproducibility.

RESULTS

It was found that results from new method correlated highly with the traditional method (R2=0.89). The cross-laboratory testing of the method showed an average interlaboratory coefficient of variation of only 18.4%.

DISCUSSION

This method provides comparable results to the more traditional centrifugation-based method with considerable time and labor savings.

Downregulation of Nrf2 promotes radiation-induced apoptosis through Nrf2 mediated Notch signaling in non-small cell lung cancer cells

The nuclear factor erythroid-2-related factor 2 (Nrf2) is a crucial regulator of the cellular antioxidant system. Nrf2 is often constitutively activated in non-small cell lung cancer (NSCLC) cell lines, which promotes cytoprotection against oxidative stress and xenobiotics. Notch1 signaling is critically implicated in cell fate determination. It has been reported that Nf2 strongly regulates Notch1 activity. However, the role of Nrf2 mediated Notch1 signaling in response to ionizing radiation (IR) remains elusive. We report that knockdown of Nrf2 promotes radiation-induced apoptosis through Nrf2 mediated Notch1 signaling in NSCLC cells. IR activated Nrf2 in a dose-dependent manner and the expression of Nrf2 was significantly elevated at 4 h after exposure. RNAi-mediated reduction of Nrf2 significantly increased endogenous ROS levels, and decreased the expression of glutamate cysteine ligase catalytic subunit (GCLC), heme oxygenase-1 (HO-1) and NAD (P) H quinine oxidoreductase-1 (NQO1) in irradiated cells. Furthermore, decrease in Nrf2 expression significantly dampened Notch1 expression following ionizing radiation exposure, and potentiated IR-induced cellular apoptosis. These results demonstrated that Nrf2 could be activated by ionizing radiation, knockdown of Nrf2 could promote radiation induced apoptosis and Nrf2-mediated Notch signaling is an important determinant in radioresistance of lung cancer cells.

Orally bioavailable, indole-based nonpeptide GnRH receptor antagonists with high potency and functional activity

Stereospecific introduction of a methyl group to the indole-3-side chain enhanced activity in our tryptamine-derived series of GnRH receptor antagonists. Further improvements were achieved by variation of the bicyclic amino moiety of the tertiary amide and by adjustment of the tether length to a pyridine or pyridone terminus. These modifications culminated in analogue 24, which had oral activity in a rat model and acceptable oral bioavailability and half-life in dogs and monkeys.

Suppression of radiation-induced migration of non-small cell lung cancer through inhibition of Nrf2-Notch Axis

Nuclear factor E2 related factor 2 (Nrf2) is a transcription factor that is associated with tumor growth and resistance to radiation. The canonical Notch signaling pathway is also crucial for maintaining non-small cell lung cancer (NSCLC). Aberrant Nrf2 and Notch signaling has repeatedly been showed to facilitate metastasis of NSCLC. Here, we show that radiation induce Nrf2 and Notch1 expression in NSCLC. Knockdown of Nrf2 enhanced radiosensitivity of NSCLC and reduced epithelial-to-mesenchymal transition. Importantly, we found that knockdown of Nrf2 dramatically decreased radiation-induced NSCLC invasion and significantly increased E-cadherin, but reduced N-cadherin and matrix metalloproteinase (MMP)-2/9 expression. We found that Notch1 knockdown also upregulated E-cadherin and suppressed N-cadherin expression. Nrf2 contributes to NSCLC cell metastatic properties and this inhibition correlated with reduced Notch1 expression. These results establish that Nrf2 and Notch1 downregulation synergistically inhibit radiation-induced migratory and invasive properties of NSCLC cells.

microRNA expression and biogenesis in cellular response to ionizing radiation

Increasing evidence demonstrates that the expression levels of microRNAs (miRNAs) significantly change upon ionizing radiation (IR) and play a critical role in cellular response to IR. Although several radiation responsive miRNAs and their targets have been identified, little is known about how miRNAs expression and biogenesis is regulated by IR-caused DNA damage response (DDR). Hence, in this review, we summarize miRNA expression and biogenesis in cellular response to IR and mainly elucidate the regulatory mechanisms of miRNA expression and biogenesis from different aspects including ataxia-telangiectasia mutated (ATM) kinase, p53/p63/p73 family and other potential factors. Furthermore, we focus on ΔNp73, which might be a potential regulator of miRNA expression and biogenesis in cellular response to IR. miRNAs could effectively activate the IR-induced DDR and modulate the radiation response and cellular radiosensitivity, which have an important potential clinical application. Therefore, thoroughly understanding the regulatory mechanisms of miRNAs expression and biogenesis in radiation response will provide new insights for clinical cancer radiotherapy.

Efficacy and safety of extended-release niacin/laropiprant plus statin vs. doubling the dose of statin in patients with primary hypercholesterolaemia or mixed dyslipidaemia

BACKGROUND

Co-administration of niacin with statin offers the potential for additional lipid management and cardiovascular risk reduction. However, niacin is underutilised because of the side effects of flushing, mediated primarily by prostaglandin D(2) (PGD(2)). A combination tablet containing extended-release niacin and laropiprant (ERN/LRPT), a PGD(2) receptor (DP1) antagonist, offers improved tolerability. This study assessed the efficacy and safety of ERN/LRPT added to statin vs. doubling the dose of statin in patients with primary hypercholesterolaemia or mixed dyslipidaemia who were not at their National Cholesterol Education Program Adult Treatment Panel III low-density lipoprotein cholesterol (LDL-C) goal based on their coronary heart disease risk category (high, moderate or low).

METHODS

After a 2- to 6-week run-in statin (simvastatin 10 or 20 mg or atorvastatin 10 mg) period, 1216 patients were randomised equally to one of two treatment groups in a double-blind fashion: group 1 received ERN/LRPT (1 g) plus the run-in statin dose and advanced to ERN/LRPT (2 g) after 4 weeks for an additional 8 weeks, with no adjustments to the run-in statin dose; group 2 received simvastatin or atorvastatin at twice their run-in statin dose and remained on this stable dose for 12 weeks.

RESULTS

ERN/LRPT added to statin (pooled across statin and statin dose) significantly improved key lipid parameters vs. the doubled statin dose (pooled): the between-treatment group difference in least squares mean per cent change [95% confidence interval (CI)] from baseline to week 12 in LDL-C (primary end-point) was -4.5% (-7.7, -1.3) and in high-density lipoprotein cholesterol (HDL-C) was 15.6% (13.4, 17.9) and in median per cent change for triglyceride (TG) was -15.4% (-19.2, -11.7). Treatment-related adverse experiences (AEs) related to flushing, pruritis, rash, gastrointestinal upset and elevations in liver transaminases and fasting serum glucose occurred more frequently with ERN/LRPT added to statin vs. statin dose doubled.

CONCLUSIONS

The addition of ERN/LRPT to ongoing statin treatment produced significantly improved lipid-modifying benefits on LDL-C, HDL-C and TG and all other lipid parameters compared with doubling the statin dose in patients with primary hypercholesterolaemia or mixed dyslipidaemia. The types of AEs that occurred at a greater frequency in the ERN/LRPT group were those typically associated with niacin.

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.

MicroRNA‑16‑5p regulates cell survival, cell cycle and apoptosis by targeting AKT3 in prostate cancer cells

Prostate cancer (PCa) is a malignancy with the highest morbidity rate in 105 countries worldwide and was a major cause of cancer‑associated death in men in 2018. Accumulating evidence suggests that microRNAs (miRNAs/miRs) have important functions in the carcinogenesis of PCa, and may provide novel treatment targets. Previous studies have indicated that miR‑16‑5p is associated with PCa. However, the relevance and importance of miR‑16‑5p in PCa carcinogenesis are still not completely understood. In the current study, we aimed to investigate the role and mechanism of miR‑16‑5p in PCa carcinogenesis. The results showed that miR‑16‑5p was markedly downregulated in PCa cells, and MTS assay, colony formation, flow cytometric analyses demonstrated that miR‑16‑5p inhibited PCa cell survival, regulated cell cycle distribution and induced apoptosis. Moreover, luciferase reporter assay and western blot analysis showed that miR‑16‑5p directly targets AKT3 (AKT serine/threonine kinase 3), which is associated with PCa carcinogenesis, and the effects of the downregulation of AKT3 were similar to the effects of upregulation of miR‑16‑5p in PC‑3 cells. In conclusion, our data clarify that miR‑16‑5p has anticancer functions in PCa cells, and our findings provide experimental evidence to highlight the potential value of miR‑targeting treatment strategies for PCa.

MicroRNA-29b-3p enhances radiosensitivity through modulating WISP1-mediated mitochondrial apoptosis in prostate cancer cells

Radiotherapy is frequently applied for clinically localized prostate cancer while its efficacy could be significantly hindered by radioresistance. MicroRNAs (miRNAs) are important regulators in mediating cellular responses to ionizing radiation (IR), and strongly associate with radiosensitivity in many cancers. In this study, enhancement of radiosensitivity by miR-29b-3p was demonstrated in prostate cancer cell line LNCaP in vitro. Results showed that miR-29b-3p expression was significantly upregulated in response to IR from both X-rays and carbon ion irradiations. Knockdown of miR-29b-3p resulted in radioresistance while overexpression of miR-29b-3p led to increased radiosensitivity (showing reduced cell viability, suppressed cell proliferation and decreased colony formation). In addition, miR-29b-3p was found to directly target Wnt1-inducible-signaling protein 1 (WISP1). Inhibition of WISP1 facilitated the mitochondrial apoptosis pathway through suppressing Bcl-XL expression while activating caspase-3 and poly (ADP-ribose) polymerase (PARP). The results indicated that miR-29b-3p was a radiosensitizing miRNAs and could enhance radiosensitivity of LNCaP cells by targeting WISP1. These findings suggested a novel treatment to overcome radioresistance in prostate cancer patients, especially those with higher levels of the WISP1 expression.

Target replacement strategy for selection of DNA aptamers against the Fc region of mouse IgG

Aptamers that recognize the IgG Fc region are of great interest because of their wide application as an immunology probing tool, for diagnostics, and as affinity agents for antibody purification. We developed a target replacement strategy as a modification of conventional Systematic Evolution of Ligands by EXponential enrichment (SELEX) in order to efficiently select and identify novel DNA aptamers against the Fc region of mouse IgG. In this new approach, multiple IgG subclasses (IgG1, IgG2a, mouse IgG Fc, and anti-HBs IgG) were sequentially used to select aptamers in one continuous SELEX. After 8 rounds of selection, the aptamers were analyzed using dot blot and an electrophoretic mobility shift assay, which showed universal binding capability to different IgG subclasses. Secondary structure analysis of the aptamers indicated that the stem-loop structure of the aptamers play an important role in binding to the common site in different mouse IgG subclasses. This demonstrated the feasibility of using multiple target replacement SELEX for the selection of aptamers. This target replacement strategy is also expected to be useful for selecting aptamers that bind common regions of molecules other than antibodies.

Carbon ion radiation inhibits glioma and endothelial cell migration induced by secreted VEGF

This study evaluated the effects of carbon ion and X-ray radiation and the tumor microenvironment on the migration of glioma and endothelial cells, a key process in tumorigenesis and angiogenesis during cancer progression. C6 glioma and human microvascular endothelial cells were treated with conditioned medium from cultures of glioma cells irradiated at a range of doses and the migration of both cell types, tube formation by endothelial cells, as well as the expression and secretion of migration-related proteins were evaluated. Exposure to X-ray radiation-conditioned medium induced dose-dependent increases in cell migration and tube formation, which were accompanied by an upregulation of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-2 and -9 expression. However, glioma cells treated with conditioned medium of cells irradiated at a carbon ion dose of 4.0 Gy showed a marked decrease in migratory potential and VEGF secretion relative to non-irradiated cells. The application of recombinant VEGF165 stimulated migration in glioma and endothelial cells, which was associated with increased FAK phosphorylation at Tyr861, suggesting that the suppression of cell migration by carbon ion radiation could be via VEGF-activated FAK signaling. Taken together, these findings indicate that carbon ion may be superior to X-ray radiation for inhibiting tumorigenesis and angiogenesis through modulation of VEGF level in the glioma microenvironment.

Aptamer-Based Sensitive Detection of Target Molecules via RT-PCR Signal Amplification

In the efforts to explore an aptamer-based approach for target sensing and detection with higher sensitivity and specificity, instead of directly labeling aptamer with fluorophores, we proposed a new strategy by attaching a polymerase chain reaction (PCR) template to an oligonucleotide aptamer selected by systematic evolution of ligands by exponential enrichment (SELEX), so that after aptamer target binding, the template moiety serves as the PCR template in real-time quantitative PCR (RT-PCR), and therefore, the binding event can be reported by the following RT-PCR signals. Using the subtractive SELEX method, the oligonucleotide aptamers specific for the Fc fragment of mouse IgG were selected and subjected to coupling with the PCR dsDNA template by using overlap and the asymmetric extension PCR method. The target binding affinity of the PCR template tethered aptamer has been proven by electrophoretic mobility shift assay (EMSA), and further template tethered aptamer mediated real-time quantitative PCR (A-PCR) was conducted to validate the application for such a template tethered aptamer to be a sensitive probe for IgG detection. The results show that the protocols of A-PCR can detect 10-fold serial dilutions of the target, demonstrating a new mechanism to convert aptamer target binding events to amplified RT-PCR signal, and the feasibility of the PCR template tethered aptamer as a facile, specific, and sensitive target probing and detection is established. This new approach also has potential applications in multiple parallel target detection and analysis in a wide range of research fields.

Loss of ZIP facilitates JAK2-STAT3 activation in tamoxifen-resistant breast cancer

Tamoxifen, a widely used modulator of the estrogen receptor (ER), targets ER-positive breast cancer preferentially. We used a powerful validation-based insertion mutagenesis method to find that expression of a dominant-negative, truncated form of the histone deacetylase ZIP led to resistance to tamoxifen. Consistently, increased expression of full-length ZIP gives the opposite phenotype, inhibiting the expression of genes whose products mediate resistance. An important example is JAK2 By binding to two specific sequences in the promoter, ZIP suppresses JAK2 expression. Increased expression and activation of JAK2 when ZIP is inhibited lead to increased STAT3 phosphorylation and increased resistance to tamoxifen, both in cell culture experiments and in a mouse xenograft model. Furthermore, data from human tumors are consistent with the conclusion that decreased expression of ZIP leads to resistance to tamoxifen in ER-positive breast cancer.

Association between preoperative serum TSH and tumor status in patients with papillary thyroid microcarcinoma

Thyroid-stimulating hormone (TSH) is a growth factor affecting the initiation or progression of papillary thyroid cancer (PTC). However, the relationship between preoperative serum TSH and papillary thyroid microcarcinoma (PTMC) remains controversial. To investigate the relationship between preoperative serum TSH and tumor status of PTMC, a multicentered retrospective study was performed from January 2014 to December 2016. The cohort of this study consisted of 1997 patients who underwent thyroid surgery. Serum TSH concentrations were measured and PTMC was diagnosed based on the post-operation pathological report. Results showed that the preoperative serum TSH concentration was not related to age and gender but was positively associated with tumor size. Furthermore, higher TSH level was associated with extra-thyroidal extension and lymph node metastasis (LNM). These results indicated that TSH might not be involved in the development of PTMC but may be associated with PTMC progression. Preoperative serum TSH concentration should be considered as risk predictor for tumor progression in patients with PTMC.

Toxic effects of 56Fe ion radiation on the zebrafish (Danio rerio) embryonic development

All living organisms and ecosystems are permanently exposed to ionizing radiation. Of all the types of ionizing radiation, heavy ions such as ⁵⁶Fe have the potential to cause the most severe biological effects. We therefore examined the effects and potential mechanisms of iron ion irradiation on the induction of developmental toxicity and apoptosis in zebrafish embryos. Zebrafish embryos at 4h post-fertilization (hpf) were divided into five groups: a control group; and four groups irradiated with 0.5, 1, 2, and 4Gy radiation, respectively. Mortality and teratogenesis were significantly increased, and spontaneous movement, heart rate, and swimming distance were decreased in the irradiated groups, accompanied by increased apoptosis. mRNA levels of genes involved in the apoptotic pathway, including p53, bax, bcl-2, and caspase-3, were significantly affected by radiation exposure. Moreover, protein expression levels of P53 and Bcl-2 changed in accordance with the corresponding mRNA expression levels. In addition, we detected the protein expression levels of γ-H2AX, which is a biomarker for radiation-induced DNA double-strand breaks, and found that γ-H2AX protein levels were significantly increased in the irradiated groups. Overall, the results of this study improve our understanding of the mechanisms of iron ion radiation-induced developmental toxicity and apoptosis, potentially involving the induction of DNA damage and mitochondrial dysfunction. The findings of this study may aid future impact assessment of environmental radioactivity in fish.

Radiosensitization to X-ray radiation by telomerase inhibitor MST-312 in human hepatoma HepG2 cells

AIMS

Previous studies in malignant cells have shown that irradiation-induced upregulation of telomerase activity, not only protected damaged telomeres, but also contributed to DNA damage repair by chromosomal healing and increased resistance to irradiation. The purpose of the present study was to investigate the radiosensitizing effect of telomerase inhibitor MST-312 and the corresponding mechanism in the human hepatoma cell line HepG2.

MAIN METHODS

Cell proliferation, telomerase activity, cell cycle distribution, DNA damage and repair, expression of p53, mitochondrial membrane potential, and cell apoptosis were measured with the MTT assay, real-time fluorescent quantitative PCR, flow cytometry, immunofluorescence, western blots, JC-1 staining, and Hoechst 33258 staining, respectively.

KEY FINDINGS

MST-312 effectively inhibited telomerase activity and showed relative weak toxicity to HepG2 cells at 4 μM. Compared with irradiation alone, 4 μM MST-312 pretreatment, followed by X-ray treatment, significantly reduced clonogenic potential. Aggravated DNA damage and increased sub-G1 cell fractions were observed. Further investigation found that homologous recombination (HR) repair protein Rad51 foci nuclear formation was blocked, and expression of p53 was elevated. These led to the collapse of mitochondrial membrane potential, and enhanced the apoptotic rate.

SIGNIFICANCE

These data demonstrated that disturbances of telomerase function could enhance the radiosensitivity of HepG2 cells to X-ray irradiation by impairing HR repair processes. In addition, telomerase inhibitor MST-312 may be useful as an adjuvant treatment in combination with irradiation.