Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

Identification of a transthyretin enhancer site that selectively binds the hepatocyte nuclear factor-3 beta isoform

The upstream proximal region of the transthyretin (TTR) promoter and a distal enhancer are sufficient to drive liver-specific expression of the TTR gene, as demonstrated by experiments in transgenic mice. Previous analyses have characterized the binding of a number of liver-enriched transcription factors of the TTR promoter including hepatocyte nuclear factors one (HNF-1), HNF-4, and three distinct HNF-3 proteins (alpha, beta, and gamma), which are members of the winged helix (fork head) family. The TTR enhancer was shown to bind members of the CCAAT/enhancer binding protein (C/EBP) family at two distinct sites (TTR-2 and TTR-3), and an oligonucleotide containing the activation protein one (AP-1) binding sequence competed for recognition to a third enhancer site (TTR-1). In this study, we have carried out a detailed analysis of the transcription factors that recognize the TTR enhancer elements (TTR-1, TTR-2, and TTR-3 oligonucleotide sequences). Analysis of the TTR-1 site demonstrates that the putative AP-1 site in the TTR enhancer binds a ubiquitously expressed factor that is distinct from the AP-1 family of proteins. Next we demonstrate, via gel shift analysis, that the TTR-3 site is recognized by the C/EBP family in liver nuclear extracts. We also show that whereas the TTR-2 enhancer site is capable of binding recombinant C/EBP proteins, it does not bind C/EBP proteins from liver nuclear extracts. The TTR-2 site does, however, contain a variant HNF-3 recognition sequence that exclusively binds the HNF-3 beta isoform. Mutation of this HNF-3 beta-specific recognition sequence caused reductions in TTR enhancer activity. We had previously observed a 95% decrease in HNF-3 alpha expression and a 20% reduction in HNF-3 beta expression in acute phase livers, which correlated with a 60% decrease in TTR gene transcription. We propose that the HNF-3 beta-specific binding site in the TTR enhancer may play a role in maintaining TTR gene expression during the acute phase response in spite of the dramatic reduction in HNF-3 alpha protein levels.

Measurement of circulating tumor cells in squamous cell carcinoma of the head and neck and patient outcomes

OBJECTIVES

We report the outcomes of patients with squamous cell carcinoma of the head and neck (HNSCC) whose circulating tumor cells (CTCs) were quantified using surface-enhanced Raman scattering (SERS) nanotechnology.

METHODS

SERS tagged with EGF was used to directly measure targeted CTCs. Patient charts were retrospectively reviewed. An optimal cut point for CTCs in 7.5 ml of peripheral blood predictive of for distant metastasis-free survival (DMFS) was identified by maximizing the log-rank statistic. An ROC analysis was also performed.

RESULTS

Of 82 patients, 13 experienced metastatic progression. The optimal cut point for DMFS was 675 CTCs (p = 0.047). For those with distant recurrence (n = 13) versus those without distant recurrence (n = 69), the CTC cut point which results in the largest combined sensitivity and specificity values is also 675 (sensitivity = 69%, specificity = 68%).

CONCLUSION

Liquid biopsy techniques in HNSCC show promise as a means of identifying patients at greater risk of disease progression.

Abstract 4359: Several cancer types are associated with increased expression and activity of the ECT2 RhoGEF and decreased expression and activity of the DLC1 RhoGAP, leading to increased RhoA activity

RhoA, which is a member of the Ras family of small GTPases, whose proteins cycle between an active GTP-bound form and an inactive GDP-bound form, frequently has high activity in advanced cancer. The RhoA protein is activated by RhoGEFs, which catalyze replacement of bound-GDP with bound-GTP, and inactivated by RhoGAPs, which hydrolyze bound-GTP to bound-GDP. In this study, we have used the The Cancer Genome Atlas (TCGA) and the NCI Clinical Proteomic Tumor Analysis Consortium (CPTAC) databases to examine the relationship between a specific RhoGEF, ECT2, and a specific RhoGAP, DLC1, and experimentally tested the biological relevance of some key findings. Using the TCGA dabase, we have found increased expression of the ECT2 RhoGEF frequently occurs in synchrony with decreased expression of the DLC1 RhoGAP in several tumor types, including lung adenocarcinoma, lung squamous cell carcinoma, and hepatocellular cancer. In lung adenocarcinoma, the combination of high ECT2 expression and low DLC1 expression level is more common in poorly differentiated tumors than in well differentiated ones. Using other publicly available datasets from NCBI Gene Expression Omnibus (GEO), the expression DLC1 and ECT2 was found to be cell cycle related, with higher DLC1 being observed exclusively in the G0 phase, while ECT2 was higher during the cell cycle, relative to G0, and peaked in the G2/M phase. In CPTAC, phosphorylation of a specific ECT2 amino acid (S861) is correlated with a poor prognosis in breast cancer. Consistent with this observation, experimental mutation of ECT2 S861 to A861 results in an ECT2 gene with loss-of-function. Point mutation of ECT2 and DLC1 were found at overall frequencies of 1.7% and 4.7%, respectively, in the tumors of the TCGA database. These cancer-associated mutations occur along the entire length of the ECT2 and DLC1 proteins, rather than being located primarily in the Rho-GEF domain of ECT2 or the Rho-GAP domain of DLC1, and experimental analysis of a subset of these mutants indicates that most of the ECT2 mutants are gain-of-function, while most of the DLC1 mutants are loss-of-function. Our results imply that ECT2 and DLC1 frequently act in concert, but in opposite directions, in cancer to increase RhoA activity.

* Authors contributed equally to this abstract

Citation Format: Dunrui Wang, Xiaolan Qian, Marian E. Durkin, Alexander G. Papageorge, Douglas R. Lowy. Several cancer types are associated with increased expression and activity of the ECT2 RhoGEF and decreased expression and activity of the DLC1 RhoGAP, leading to increased RhoA activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4359.

Abstract 5522: Cancer-associated point mutant in the START domain of DLC1 encodes a protein attenuated for tumor suppressor activity and for binding both Caveolin-1 and PLCD1 but not for Rho-GAP activity

The tumor suppressor gene DLC1 encodes a multi-domain protein, including a Rho-GAP domain (Rho GTPase activating protein domain) that negatively regulates the activity of RhoA, RhoB, and RhoC, and has been hypothesized to be the basis of its tumor suppressor functions. Other well recognized DLC1 domains are an N-terminal sterile alpha motif (SAM) domain, and a C-terminal steroidogenic acute regulatory protein-related lipid transfer (START) domain. DLC1 is down-regulated in several malignancies by gene deletion, epigenetic promoter methylation, or post-translational mechanisms. In addition, we have recently determined, by analyzing the TCGA database that point mutations in the DLC1 gene occur frequently, and have provided evidence that most of the mutant proteins display attenuated tumor suppressor function. Moreover, the mutations are distributed along the entire coding region, implying that regions of DLC1 in addition to its RhoGAP domain contribute to its full tumor suppressor activity.

Several DLC1 binding partners, in addition to Rho-GTP, have been identified. They include Caveolin-1, the principal structural component and marker of caveolae, which interacts with the START domain of DLC1. The distribution of caveolae is closely related to intracellular events, such as MAPK activation or the control of intracellular Ca2+ levels. Phospholipase C delta 1 (PLCD1) transforms PtdIns(4,5)P2 (PIP2) into inositol triphosphate (IP3) and diacyglycerol (DAG), which participate in intracellular Ca2+ mobilization and protein kinase C activation, respectively. p122RhoGAP, the rat homolog of DLC1, was initially cloned as a novel PLCD1-interacting protein, but the interacting region of PLCD1 with p122RhoGAP was not identified. In addition, others have concluded the function of PLCD1 is not affected by human DLC1.

In the current study, we have characterized a colon cancer-associated DLC1 mutant (R947C) whose mutation lies in the START domain. The mutant has an attenuated tumor suppressor phenotype, as determined by deficiency in reduction of growth in soft agar and cell migration. Compared with the wild type, the binding of the mutant to PLCD1 and to Caveolin-1 is reduced, but its RhoGAP activity is intact. In addition, phosphorylation of Caveolin-1 by Src at Tyr 14 reduces its interaction with wild type DLC1, and Caveolin-1 and PLCD1 interact in vivo more efficiently with each other in the absence of DLC1. Moreover, wild type DLC1, Caveolin-1 and PLCD1 possess cooperative tumor suppressor activities in cells expressing all three genes. Overall, this study provides new insight into the role of the START domain of DLC1, and reinforces the Rho-GAP-independent regulation of tumor growth by DLC1.

Citation Format: Beatriz Sanchez-Solana, Xiaolan Qian, Dunrui Wang, Marian Durkin, Brajendra Tripathi, Alex Papageorge, Douglas R. Lowy. Cancer-associated point mutant in the START domain of DLC1 encodes a protein attenuated for tumor suppressor activity and for binding both Caveolin-1 and PLCD1 but not for Rho-GAP activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5522.

Differences in teachers verbal responsiveness to groups of children with ASD who vary in cognitive and language abilities

BACKGROUND

This study aimed to examine whether verbal responsiveness in special education teachers varied among subgroups of children with autism spectrum disorder (n = 112) who differed in cognitive and language abilities.

METHODS

Participants were divided into clusters using cluster analysis based on standardised cognitive and language tests using k-mean clustering. For each child, a 15-min video of free play in school setting was collected. Three types of responsive utterances were coded: follow-in directives for behaviour, follow-in directives for language and follow-in comments.

RESULTS

Results showed that the three groups did not differ in overall verbal responsiveness after controlling for engagement, classroom type, age and gender. However, groups differ in follow-in directives for language, but not in follow-in directives for behaviours or follow-in comments. Compared with children with autism spectrum disorder who had higher cognitive and language ability, children with more severe impairments received fewer follow-in directives for language. Moreover, children with more cognitive and language impairments produced fewer amount of vocal/verbal acts, which results in receiving fewer verbal responses from their teachers. Additionally, teachers from the three groups did not differ in their responses to the child's verbal/vocal acts when the number of the child's verbal/vocal acts were controlled for.

CONCLUSION

Findings suggest child characteristics are related to the type of teachers' verbal responses in preschools. This difference in follow-in directives for questions may be related to language or other outcomes that warrant further investigations.

Inhibition of HHIP Promoter Methylation Suppresses Human Gastric Cancer Cell Proliferation and Migration

BACKGROUND/AIMS

Human hedgehog-interacting protein (HHIP) is a negative regulator of the hedgehog (HH) signaling pathway. It is deregulated in gastric cancer. The underlying molecular mechanism of HHIP-induced inhibition of HH signaling remains to be determined.

METHODS

A lentiviral HHIP expression vector ("LV-HHIP") was established to exogenously over-express HHIP in gastric cancer cells. HHIP protein and mRNA were tested by Western blotting assay and quantitative real-time PCR assay, respectively. Cell survival was tested by the Cell Counting Kit-8 (CCK-8) assay. Cell proliferation was examined by the BrdU ELISA assay and [H3] Thymidine DNA incorporation assay. Cell invasion and migration were tested by the phagokinetic track assay and the "Transwell" assay. The bisulfite-sequencing PCR was applied to test HHIP promoter methylation.

RESULTS

In the established (AGS cell line) and primary human gastric cancer cells, LV-HHIP transfection increased HHIP expression and inhibited cancer cell survival and proliferation as well as cell migration and invasion. Furthermore, LV-HHIP significantly attenuated promoter methylation of the endogenous HHIP gene in AGS cells, causing it upregulation. Inhibition of methylation by 5-aza-dc similarly induced HHIP expression in gastric cancer cells, which inhibited cancer cell proliferation and migration.

CONCLUSIONS

Our results suggest that inhibition of HHIP promoter methylation can efficiently inhibit human gastric cancer cell proliferation and migration.

DLC1 is the principal biologically-relevant down-regulated DLC family member in several cancers

The RHO family of RAS-related GTPases in tumors may be activated by reduced levels of RHO GTPase accelerating proteins (GAPs). One common mechanism is decreased expression of one or more members of the Deleted in Liver Cancer (DLC) family of Rho-GAPs, which comprises three closely related genes (DLC1, DLC2, and DLC3) that are down-regulated in a wide range of malignancies. Here we have studied their comparative biological activity in cultured cells and used publicly available datasets to examine their mRNA expression patterns in normal and cancer tissues, and to explore their relationship to cancer phenotypes and survival outcomes. In The Cancer Genome Atlas (TCGA) database, DLC1 expression predominated in normal lung, breast, and liver, but not in colorectum. Conversely, reduced DLC1 expression predominated in lung squamous cell carcinoma (LSC), lung adenocarcinoma (LAD), breast cancer, and hepatocellular carcinoma (HCC), but not in colorectal cancer. Reduced DLC1 expression was frequently associated with promoter methylation in LSC and LAD, while DLC1 copy number loss was frequent in HCC. DLC1 expression was higher in TCGA LAD patients who remained cancer-free, while low DLC1 had a poorer prognosis than low DLC2 or low DLC3 in a more completely annotated database. The poorest prognosis was associated with low expression of both DLC1 and DLC2 (P < 0.0001). In cultured cells, the three genes induced a similar reduction of Rho-GTP and cell migration. We conclude that DLC1 is the predominant family member expressed in several normal tissues, and its expression is preferentially reduced in common cancers at these sites.

John J, Strauss T, Szelc AM, Tagg N, Terao K, Thomson M, Toups M, Tsai YT, Tufanli S, Usher T, Van De Pontseele W, Van de Water RG, Viren B, Weber M, Wickremasinghe DA, Wolbers S, Wongjirad T, Woodruff K, Yang T, Yates L, Zeller GP, Zennamo J, Zhang C. The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector

The development and operation of liquid-argon time-projection chambers for neutrino physics has created a need for new approaches to pattern recognition in order to fully exploit the imaging capabilities offered by this technology. Whereas the human brain can excel at identifying features in the recorded events, it is a significant challenge to develop an automated, algorithmic solution. The Pandora Software Development Kit provides functionality to aid the design and implementation of pattern-recognition algorithms. It promotes the use of a multi-algorithm approach to pattern recognition, in which individual algorithms each address a specific task in a particular topology. Many tens of algorithms then carefully build up a picture of the event and, together, provide a robust automated pattern-recognition solution. This paper describes details of the chain of over one hundred Pandora algorithms and tools used to reconstruct cosmic-ray muon and neutrino events in the MicroBooNE detector. Metrics that assess the current pattern-recognition performance are presented for simulated MicroBooNE events, using a selection of final-state event topologies.

Publisher's Note: JLab Measurements of the ^{3}He Form Factors at Large Momentum Transfers [Phys. Rev. Lett. 119, 162501 (2017)]

This corrects the article DOI: 10.1103/PhysRevLett.119.162501.

Receptor tyrosine kinase activation of RhoA is mediated by AKT phosphorylation of DLC1

A new common mechanism for increasing RhoA-GTP is identified in Tripathi et al. The increased RhoA-GTP results from signaling mechanisms that phosphorylate and attenuate the DLC1 tumor suppressor, which encodes RhoGAP. The potentially reversible nature of this attenuation may have therapeutic relevance in cancer.

We report several receptor tyrosine kinase (RTK) ligands increase RhoA–guanosine triphosphate (GTP) in untransformed and transformed cell lines and determine this phenomenon depends on the RTKs activating the AKT serine/threonine kinase. The increased RhoA-GTP results from AKT phosphorylating three serines (S298, S329, and S567) in the DLC1 tumor suppressor, a Rho GTPase-activating protein (RhoGAP) associated with focal adhesions. Phosphorylation of the serines, located N-terminal to the DLC1 RhoGAP domain, induces strong binding of that N-terminal region to the RhoGAP domain, converting DLC1 from an open, active dimer to a closed, inactive monomer. That binding, which interferes with the interaction of RhoA-GTP with the RhoGAP domain, reduces the hydrolysis of RhoA-GTP, the binding of other DLC1 ligands, and the colocalization of DLC1 with focal adhesions and attenuates tumor suppressor activity. DLC1 is a critical AKT target in DLC1-positive cancer because AKT inhibition has potent antitumor activity in the DLC1-positive transgenic cancer model and in a DLC1-positive cancer cell line but not in an isogenic DLC1-negative cell line.

JLab Measurements of the ^{3}He Form Factors at Large Momentum Transfers

The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25  fm^{-2}≤Q^{2}≤61  fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q^{2}=49.3  fm^{-2} and for the charge form factor at Q^{2}=62.0  fm^{-2}. Both minima are predicted to exist in the Q^{2} range accessible by this Jefferson Lab experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.

Abstract 1364: Direct phosphorylation and attenuation of the DLC1 tumor suppressor by SRC kinase: a new mechanism of SRC-dependent activation of Rho with translational implications

Many tumors have high SRC activity and constitutive up-regulation of Rho-GTP, which is frequently implicated in the neoplastic process and tumor progression to metastasis, but the mechanistic link is unclear. Here we identify the DLC1 tumor suppressor, which encodes a RhoGAP, as a previously unrecognized direct target of the SRC kinase, in untransformed cells and in tumor-derived cell lines, which upregulates Rho-GTP. SRC kinase directly phosphorylates two Tyrosines in DLC1: Y451 and Y701. SRC phosphorylation of DLC1-Y701, which is located in the DLC1 RhoGAP domain, attenuates its RhoGAP activity and tumor suppressor function by inhibiting the binding of active Rho-GTP to the RhoGAP domain, reducing the hydrolysis of active Rho-GTP to inactive Rho-GDP and resulting in an increase in Rho-GTP. The role of SRC phosphorylation of DLC1-Y451 is to diminish DLC1 binding to tensin, which further reduces the tumor suppressor functions, as measured by cell migration rate, anchorage-independent growth, and tumor formation in nude mice, independently of Rho-GTP. We also found that ERK1 cooperates with SRC by phosphorylating DLC1-S129, which enhances the binding of the SRC SH3 domain to this region of DLC1, and increases SRC-dependent phosphorylation of Y451 and Y701. The cooperative effects reduce RhoGAP activity, increase Rho-GTP and Rho/ROCK/MRLC signaling, and attenuate DLC1 tumor suppressor functions. DLC1 preferentially binds active SRC, which reduces overall SRC activity. Therefore, SRC activity tends to be lower in cells that express high levels of endogenous DLC1, compared with cells in which DLC1 expression has been down-regulated. Although SRC targets two DLC1 functions that contribute to its tumor suppressor activity, DLC1 binds several ligands in addition to tensin that also contribute to its tumor suppressor functions. Therefore, it would not be surprising if high SRC activity were associated with selective pressure for down-regulation of DLC1 expression. Consistent with this hypothesis, the combination high SRC expression and low DLC1 expression was associated with a poor prognosis in lung adenocarcinomas (p=0.005) in TCGA. The potentially reversible nature of the SRC-induced attenuation of DLC1 function can be exploited therapeutically. In two systems that have high SRC activity and express DLC1 - the mouse MMTV-PyMT cancer model and a human lung cancer cell line - the Src inhibitor PP1 has potent antitumor activity, as it reduces DLC1 Tyrosine phosphorylation, reactivates DLC1, and reduces Rho-GTP. However, PP1 has marginal antitumor activity an isogenic DLC1-negative strain of the lung cancer line, as the inhibitor does not reactivate DLC1 and does not alter Rho-GTP levels. The results highlight the potential importance of tumor suppressor reactivation as a biomarker for predicting and monitoring the response to SRC inhibitors.

Citation Format: Brajendra K. Tripathi, Xiaolan Qian, Ming Zhou, Dunrui Wang, Marian Durkin, Alex G. Papageorge, Douglas R. Lowy. Direct phosphorylation and attenuation of the DLC1 tumor suppressor by SRC kinase: a new mechanism of SRC-dependent activation of Rho with translational implications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1364. doi:10.1158/1538-7445.AM2017-1364

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Characterization of Microcystin-Induced Dualistic Toxic Effects on Primary Rat Hepatocytes

Microcystins (MCs) comprise a group of widely characterized cyclic heptapeptides able to induce a series of liver injuries, including acute liver failure and primary liver cancer. Although the dualistic effects of MCs have been postulated, the specific action mode according to the exposure dosage of MCs remains unknown. In the present study, primarily cultured rat hepatocytes were used to systematically investigate hepatotoxic characteristics of MC-LR (one of the most abundant and toxic MCs variants). Results showed that the dualistic toxicity of MC-LR on hepatocytes is dose dependent. Specifically, MC-LR at a high dose (>10-8 mol/L) induced a significant reduction in cell viability, whereas low-dose MC-LR (<10-8 mol/L) was observed to promote cell proliferation. Oxidative stress measurements showed that reactive oxygen species (ROS) levels undergo a massive and rapid increase in high-dose MC-LR-treated hepatocytes and a mild and slow increase in low-dose MC-LR-treated hepatocytes. These in vitro data suggest that MC-LR is able to exert dualistic toxic effects on hepatocytes through the "two-faced" character of ROS, which causes cell death or even necrosis at high concentrations and promotes cell proliferation exclusively at low or transient concentrations.

Controllable picoliter pipetting using hydrophobic microfluidic valves

A picoliter pipetting technique using the microfluidic method is presented. Utilizing the hydrophobic self-assembled monolayer films patterned in microchannels as pressure-controlled valves, a small volume of liquid can be separated by a designed channel trap and then ejected from the channel end at a higher pressure. The liquid trap section is composed of a T-shaped channel junction and a hydrophobic patch. The liquid volume can be precisely controlled by varying the distance of the hydrophobic patch from the T-junction. By this means, liquid less than 100 pl can be separated and pipetted. The developed device is potentially useful for sample dispensing in biological, medical, and chemical applications.

Astaxanthin increases radiosensitivity in esophageal squamous cell carcinoma through inducing apoptosis and G2/M arrest

Nowadays esophageal squamous cell carcinoma (ESCC) is primarily treated by a comprehensive approach combining surgical resection and neoadjuvant chemo- or radiotherapy. However, ESCC is resistant to radiation therapy, resulting in its invasion, infiltration, and metastasis. It usually has rapidly progressed and has a poor outcome clinically. The purpose of this study is to determine the potential radiosensitizing effect of astaxanthin (ATX) and explore the underlying mechanisms in ESCC cells in vitro. ESCC cell lines were exposure to irradiation, in the presence or absence of ATX treatment. Cell viability and radiosensitization were tested by CCK8 assay and clonogenic survival assay, respectively. Cell apoptosis and the changes of cell cycle distribution were observed by flow cytometry. The protein expression of Bcl2, Bax, CyclinB1, and Cdc2 was examined by western blot analysis. It was shown that ATX improved radiosensitivity of ESCC cells and induced apoptosis and G2/M arrest via inhibiting Bcl2, CyclinB1, Cdc2, and promoting Bax expression. In conclusion, ATX might function as a promising radiosensitizer in ESCC cells by leading to apoptosis and G2/M arrest.