PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (146)
 

Clipboard (0)
None

Select a Filter Below

Journals
more »
Year of Publication
more »
1.  Mode-Division-Multiplexing of Multiple Bessel-Gaussian Beams Carrying Orbital-Angular-Momentum for Obstruction-Tolerant Free-Space Optical and Millimetre-Wave Communication Links 
Scientific Reports  2016;6:22082.
We experimentally investigate the potential of using ‘self-healing’ Bessel-Gaussian beams carrying orbital-angular-momentum to overcome limitations in obstructed free-space optical and 28-GHz millimetre-wave communication links. We multiplex and transmit two beams (l = +1 and +3) over 1.4 metres in both the optical and millimetre-wave domains. Each optical beam carried 50-Gbaud quadrature-phase-shift-keyed data, and each millimetre-wave beam carried 1-Gbaud 16-quadrature-amplitude-modulated data. In both types of links, opaque disks of different sizes are used to obstruct the beams at different transverse positions. We observe self-healing after the obstructions, and assess crosstalk and power penalty when data is transmitted. Moreover, we show that Bessel-Gaussian orbital-angular-momentum beams are more tolerant to obstructions than non-Bessel orbital-angular-momentum beams. For example, when obstructions that are 1 and 0.44 the size of the l = +1 beam, are placed at beam centre, optical and millimetre-wave Bessel-Gaussian beams show ~6 dB and ~8 dB reduction in crosstalk, respectively.
doi:10.1038/srep22082
PMCID: PMC4772084  PMID: 26926068
2.  One-step Preparation of Nanoarchitectured TiO2 on Porous Al as Integrated Anode for High-performance Lithium-ion Batteries 
Scientific Reports  2016;6:20138.
Titanium dioxide (TiO2) is an attractive anode material for energy storage devices due to its low-volume-change and high safety. However, TiO2 anodes usually suffer from poor electrical and ionic conductivity, thus causing dramatic degradation of electrochemical performance at rapid charge/discharge rates, which has hindered its use in energy storage devices. Here, we present a novel strategy to address this main obstacle via using nanoarchitectured TiO2 anode consisting of mesoporous TiO2 wrapped in carbon on a tunnel-like etched aluminum substrate prepared by a simple one-step approach. As a result of this nanoarchitecture arrangement, the anode exhibits excellent rate performance and superior cyclability. A rate up to 100 C is achieved with a high specific capacity of about 95 mA h g−1, and without apparent decay after 8,000 cycles.
doi:10.1038/srep20138
PMCID: PMC4740746  PMID: 26841711
3.  Identification of Small Activating RNAs that Enhance Endogenous OCT4 Expression in Human Mesenchymal Stem Cells 
Stem Cells and Development  2014;24(3):345-353.
Ectopic overexpression of transcription factors has been used to reprogram cell fate. For example, virus-mediated overexpression of four transcription factors OCT4, SOX2, MYC, and KLF4, known as Yamanaka factors, can convert somatic cells to induced pluripotent stem (iPS) cells. However, gene-specific switch-on of endogenous gene production without the use of foreign DNA remains a challenge. The small RNA machinery that comprised small RNAs and Argonaute proteins is known to silence gene expression, but can be repurposed to activate gene expression when directed to gene promoters, a phenomenon known as RNA activation or RNAa. By screening of dsRNAs targeting OCT4 promoter, we identified a small activating RNA (saRNA) that activated OCT4 expression in several types of human mesenchymal stem cells (MSCs). We found that saRNA-induced OCT4 activation can be further enhanced by a histone deacetylase inhibitor, valproic acid. Furthermore, introducing OCT4 saRNA in combination with viruses encoding the remaining three Yamanaka factors (SOX2, MYC, and KLF4) into MSCs led to the derivation of partially reprogrammed iPS cells. Findings from this study suggest that, with further optimization, RNAa can be a powerful tool to reprogram cell fate by inducing the expression of endogenous genes.
doi:10.1089/scd.2014.0290
PMCID: PMC4303016  PMID: 25232932
4.  RNAa in action: From the exception to the norm 
RNA Biology  2015;11(10):1221-1225.
Small RNA programmed Argonautes are sophisticated cellular effector platforms known to be involved in a diverse array of functions ranging from mRNA cleavage, translational inhibition, DNA elimination, epigenetic silencing, alternative splicing and even gene activation. First observed in human cells, small RNA-induced gene activation, also known as RNAa, involves the targeted recruitment of Argonaute proteins to specific promoter sequences followed by induction of stable epigenetic changes which promote transcription. The existence of RNAa remains contentious due to its elusive mechanism. A string of recent studies in C. elegans provides unequivocal evidence for RNAa's fundamental role in sculpting the epigenetic landscape and maintaining active transcription of endogenous genes and supports the presence of a functionally sophisticated network of small RNA-Argonaute pathways consisting of opposite yet complementary “yin and yang” regulatory elements. In this review, we summarize key findings from recent studies of endogenous RNAa in C. elegans, with an emphasis on the Argonaute protein CSR-1.
doi:10.4161/15476286.2014.972853
PMCID: PMC4615537  PMID: 25602906
Argonaute; epigenetic memory; gene expression; RNAa; RNAe
5.  Coupled elasticity–diffusion model for the effects of cytoskeleton deformation on cellular uptake of cylindrical nanoparticles 
Journal of the Royal Society Interface  2015;12(102):20141023.
Molecular dynamic simulations and experiments have recently demonstrated how cylindrical nanoparticles (CNPs) with large aspect ratios penetrate animal cells and inevitably deform cytoskeletons. Thus, a coupled elasticity–diffusion model was adopted to elucidate this interesting biological phenomenon by considering the effects of elastic deformations of cytoskeleton and membrane, ligand–receptor binding and receptor diffusion. The mechanism by which the binding energy drives the CNPs with different orientations to enter host cells was explored. This mechanism involved overcoming the resistance caused by cytoskeleton and membrane deformations and the change in configurational entropy of the ligand–receptor bonds and free receptors. Results showed that deformation of the cytoskeleton significantly influenced the engulfing process by effectively slowing down and even hindering the entry of the CNPs. Additionally, the engulfing depth was determined quantitatively. CNPs preferred or tended to vertically attack target cells until they were stuck in the cytoskeleton as implied by the speed of vertically oriented CNPs that showed much faster initial engulfing speeds than horizontally oriented CNPs. These results elucidated the most recent molecular dynamics simulations and experimental observations on the cellular uptake of carbon nanotubes and phagocytosis of filamentous Escherichia coli bacteria. The most efficient engulfment showed the stiffness-dependent optimal radius of the CNPs. Cytoskeleton stiffness exhibited more significant influence on the optimal sizes of the vertical uptake than the horizontal uptake.
doi:10.1098/rsif.2014.1023
PMCID: PMC4277092  PMID: 25411410
cylindrical nanoparticles; cellular uptake; diffusive receptor; cytoskeleton deformation
6.  Annular pancreas in Trichorhinophalangeal syndrome type II with 8q23.3-q24.12 interstitial deletion 
Background
Trichorhinophalangeal syndrome type II (TRPS II, OMIM # 150230) is a rare autosomal dominant genetic disorder characterized by craniofacial and skeletal abnormalities. Loss of functional copies of the TRPS1 gene at 8q23.3 and the EXT1 gene at 8q24.11 are considered to be responsible for the syndrome.
Case Presentation
Herewith, we report an 8-year-old girl with sparse scalp hair, bulbous nose, thin upper lip, broad eyebrows, phalangeal abnormalities of both hands/toes, multiple exostoses, mild intellectual impairment and severe malnutrition. In addition, the patient also had annular pancreas, a rare co-existing feature in patients with TRPS II.
Conclusions
A contiguous 5.47 Mb deletion involving 8q23.3-q24.12 was detected by array comparative genomic hybridization (aCGH), leading to haploinsufficiency of 10 protein coding genes, 1 long non-coding RNA and 1 microRNA. Quantitative PCR (qPCR) examination confirmed half-reduced DNA copy of the patient and normal expression of both parents, indicating a de novo origin of the deletion and complete penetrance of the mutation.
doi:10.1186/s13039-015-0201-0
PMCID: PMC4678473  PMID: 26673557
Annular pancreas; 8q23.3-q24.12 deletion; Trichorhinophalangeal syndrome type II; Chinese; qPCR
7.  Proteome Analysis of Renoprotection Mediated by a Novel Cyclic Helix B Peptide in Acute Kidney Injury 
Scientific Reports  2015;5:18045.
We developed a novel, erythropoietin-derived, non-erythropoiesis, cyclic helix B peptide (CHBP) that displays potent renoprotection against acute kidney injury (AKI). To determine the mechanism of CHBP-mediated protection, we investigated the proteomic profile of mice treated with CHBP in a kidney ischemia-reperfusion (IR) injury model. The isobaric tags for relative and absolute quantitation (iTRAQ)-labeled samples were analyzed using a QSTAR XL LC/MS system. In total, 38 differentially expressed proteins (DEPs) were shared by all experimental groups, while 3 DEPs were detected specifically in the IR + CHBP group. Eight significant pathways were identified, and oxidative phosphorylation was shown to be the most important pathway in CHBP-mediated renoprotection. The significant DEPs in the oxidative phosphorylation pathway elicited by CHBP are NADH-ubiquinone oxidoreductase Fe-S protein 6 (NDUFS6), alpha-aminoadipic semialdehyde synthase (AASS) and ATP-binding cassette sub-family D member 3 (ABCD3). The DEPs mentioned above were verified by RT-qPCR and immunostaining in mouse kidneys. We tested 6 DEPs in human biopsy samples from kidney transplant recipients. The trend of differential expression was consistent with that in the murine model. In conclusion, this study helps to elucidate the pharmacological mechanisms of CHBP before clinical translation.
doi:10.1038/srep18045
PMCID: PMC4674932  PMID: 26655840
8.  Cyclic helix B peptide inhibits ischemia reperfusion-induced renal fibrosis via the PI3K/Akt/FoxO3a pathway 
Renal fibrosis is a main cause of end-stage renal disease. Clinically, there is no beneficial treatment that can effectively reverse the progressive loss of renal function. We recently synthesized a novel proteolysis-resistant cyclic helix B peptide (CHBP) that exhibits promising renoprotective effects. In this study, we evaluated the effect of CHBP on renal fibrosis in an in vivo ischemia reperfusion injury (IRI) model and in vitro TGF-β-stimulated tubular epithelial cells (TCMK-1 and HK-2) model. In the IRI in vivo model, mice were randomly divided into sham (sham operation), IR and IR + CHBP groups (n = 6). CHBP (8 nmol/kg) was administered intraperitoneally at the onset of reperfusion, and renal fibrosis was evaluated at 12 weeks post-reperfusion. Our results showed that CHBP markedly attenuated the IRI-induced deposition of collagen I and vimentin. In the in vitro model, CHBP reversed the TGF-β-induced down-regulation of E-cadherin and up-regulation of α-SMA and vimentin. Furthermore, CHBP inhibited the phosphorylation of Akt and Forkhead box O 3a (FoxO3a), whose anti-fibrotic effect could be reversed by the 3-phosphoinositide-dependent kinase-1 (PI3K) inhibitor wortmannin as well as FoxO3a siRNA. These findings demonstrate that CHBP attenuates renal fibrosis and the epithelial-mesenchymal transition of tubular cells, possibly through suppression of the PI3K/Akt pathway and thereby the inhibition FoxO3a activity.
Electronic supplementary material
The online version of this article (doi:10.1186/s12967-015-0699-2) contains supplementary material, which is available to authorized users.
doi:10.1186/s12967-015-0699-2
PMCID: PMC4641348  PMID: 26554357
Cyclic helix B peptide; Renal ischemia reperfusion injury; Fibrosis; Akt; FoxO3
9.  DR-02TEMOZOLOMIDE SENSITIZES GLIOMA STEM CELLS TO TRAIL-INDUCED APOPTOSIS THROUGH UPREGULATION OF c-CBL 
Neuro-Oncology  2014;16(Suppl 5):v63.
TRAIL-induced apoptosis is inhibited in GSCs. In this study, we investgated whether or not the widely used chemotherapeutic agent-TMZ can sensitize TRAIL treatment in GSCs, related mechanism was investigated in cultured glioma stem cells (GSCs) and primary glioma cells (PGCs) from patients. We found that the expression of c-Fas-associated death domain-like interleukin 1-converting enzyme-like inhibitory protein long and short isoforms (c-FLIPL and c-FLIPS, respectively) was significantly higher in GSCs than in PGCs, and was associated with greater tolerance to TRAIL treatment in the former. Application of the chemotherapeutic drug temozolomide (TMZ) induced the upregulation of casitas B-lineage lymphoma(c-Cbl) and downregulation of c-FLIPL and c-FLIPS expression in GSCs, and when combined with TRAIL promoted GSC apoptosis. These results suggest that combination therapy with TMZ and TRAIL may have clinical applicability for glioma treatment.
doi:10.1093/neuonc/nou252.2
PMCID: PMC4218041
10.  Comparative analyses of fecal microbiota in Tibetan and Chinese Han living at low or high altitude by barcoded 454 pyrosequencing 
Scientific Reports  2015;5:14682.
Knowledge about the impact of altitude and ethnicity on human gut microbiota is currently limited. In this study, fecal microbiota from 12 Tibetans (T group), 11 Chinese Han living in Tibet (HH group) and 12 Chinese Han living in Shaanxi province (LH group) were profiled by 454 pyrosequencing. Analysis of UniFrac principal coordinates showed significant structural changes in fecal microbiota among the three groups. There were significant differences in the composition of fecal microbiota among the three groups at phylum and genus levels. At the phylum level, the fecal samples of HH and T groups had higher relative abundances of Firmicutes, whereas the LH group had a higher relative abundance of Bacteroidetes. These changes at the phylum level reflected different dominant genus compositions. Compared with the LH group, changes of Firmicutes and Bacteroidetes were mainly due to a significant decrease of Prevotella in the HH group and were primarily attributable to significant decreases of Bacteroides and Prevotella as well as a significant increase of Catenibacterium in the T group. In conclusion, our results suggest that high altitude may contribute to shaping human gut microbiota. Genetic and dietary factors may also explain the different microbiota compositions between Tibetan and Chinese Han.
doi:10.1038/srep14682
PMCID: PMC4595765  PMID: 26443005
11.  GATA-3 dose-dependent checkpoints in early T cell commitment1 
GATA-3 expression is crucial for T cell development and peaks during commitment to the T-cell lineage, midway through the CD4−CD8− (DN) 1-3 stages. We used RNA interference and conditional deletion to reduce GATA-3 protein acutely at specific points during T-cell differentiation in vitro. Even moderate GATA-3 reduction killed DN1 cells, delayed progression to DN2 stage, skewed DN2 gene regulation, and blocked appearance of DN3 phenotype. Although a Bcl-2 transgene rescued DN1 survival and improved DN2 cell generation, it did not restore DN3 differentiation. Gene expression analyses (qPCR, RNA-seq) showed that GATA-3-deficient DN2 cells quickly upregulated genes including Spi1 (PU.1) and Bcl11a and downregulated genes including Cpa3, Ets1, Zfpm1, Bcl11b, Il9r and Il17rb, with gene-specific kinetics and dose-dependencies. These targets could mediate two distinct roles played by GATA-3 in lineage commitment, as revealed by removing wildtype or GATA-3-deficient early T-lineage cells from environmental Notch signals. GATA-3 worked as a potent repressor of B-cell potential even at low expression levels, so that only full deletion of GATA-3 enabled pro-T cells to reveal B-cell potential. The ability of GATA-3 to block B-cell development did not require T-lineage commitment factor Bcl11b. In prethymic multipotent precursors, however, titration of GATA-3 activity using tamoxifen-inducible GATA-3 showed that GATA-3 inhibits B and myeloid developmental alternatives at different threshold doses. Furthermore, differential impacts of a GATA-3 obligate repressor construct imply that B and myeloid development are inhibited through distinct transcriptional mechanisms. Thus, the pattern of GATA-3 expression sequentially produces B-lineage exclusion, T-lineage progression, and myeloid-lineage exclusion for commitment.
doi:10.4049/jimmunol.1301663
PMCID: PMC4170028  PMID: 25172496
12.  Dual E627K and D701N mutations in the PB2 protein of A(H7N9) influenza virus increased its virulence in mammalian models 
Scientific Reports  2015;5:14170.
The ongoing avian H7N9 influenza outbreaks in China have caused significant human fatal cases and the virus is becoming established in poultry. Mutations with potential to increase mammalian adaptation have occurred in the polymerase basic protein 2 (PB2) and other viral genes. Here we found that dual 627K and 701N mutations could readily occur during transmission of the virus among ferrets via direct physical contact, and these mutations conferred higher polymerase activity and improved viral replication in mammalian cells, and enhanced virulence in mice. Special attention needs to be paid to patients with such mutations, as these may serve as an indicator of higher virus replication and increased pathogenicity.
doi:10.1038/srep14170
PMCID: PMC4585756  PMID: 26391278
13.  Targeted expression of BikDD combined with metronomic doxorubicin induces synergistic antitumor effect through Bax activation in hepatocellular carcinoma 
Oncotarget  2015;6(27):23807-23819.
Conventional chemotherapy is commonly used to treat advanced non-resectable hepatocellular carcinoma (HCC) but this treatment modality has not demonstrated convincing survival benefit in HCC patients. Our previous studies indicated that targeted expression of therapeutic BikDD driven by a liver cancer-specific α-fetoprotein promoter/enhancer (eAFP) in the VISA backbone (eAFP-VISA-BikDD) significantly and specifically kills HCC cells in multiple orthotopic animal models. To enhance its therapeutic efficacy, we combined eAFP-VISA-BikDD with chemotherapeutic agents and found that eAFP-VISA-BikDD plus doxorubicin (Dox) or 5-fluorouracil (5-FU) demonstrated synergistic cytotoxicity in HCC cells. Specifically, the combination of eAFP-VISA-BikDD plus Dox markedly induced apoptosis via increased Bax mitochondrial translocation and cytoplasmic cytochrome c release. Compared with either agent alone, a low dose of Dox combined with eAFP-VISA-BikDD induced better antitumor effect and prolonged longer survival of mice in two orthotopic liver cancer xenograft models. Our findings provide strong preclinical support for evaluating the combined therapy of eAFP-VISA-BikDD and Dox in a clinical setting as a treatment option for HCC.
PMCID: PMC4695153  PMID: 26247632
synergistic antitumor effect; combination therapy; orthotopic animal model; hepatocellular carcinoma; metronomic chemotherapy
14.  Bacterial inhibition potential of 3D rapid-prototyped magnesium-based porous composite scaffolds–an in vitro efficacy study 
Scientific Reports  2015;5:13775.
Bone infections are common in trauma-induced open fractures with bone defects. Therefore, developing anti-infection scaffolds for repairing bone defects is desirable. This study develoepd novel Mg-based porous composite scaffolds with a basal matrix composed of poly(lactic-co-glycolicacid) (PLGA) and tricalcium phosphate (TCP). A unique low-temperature rapid prototyping technology was used to fabricate the scaffolds, including PLGA/TCP (PT), PLGA/TCP/5%Mg (PT5M), PLGA/TCP/10%Mg (PT10M), and PLGA/TCP/15%Mg (PT15M). The bacterial adhesion and biofilm formation of Staphylococcus aureus were evaluated. The results indicated that the Mg-based scaffolds significantly inhibited bacterial adhesion and biofilm formation compared to PT, and the PT10M and PT15M exhibited significantly stronger anti-biofilm ability than PT5M. In vitro degratation tests revealed that the degradation of the Mg-based scaffolds caused an increase of pH, Mg2+ concentration and osmolality, and the increased pH may be one of the major contributing factors to the antibacterial function of the Mg-based scaffolds. Additionally, the PT15M exhibited an inhibitory effect on cell adhesion and proliferation of MC3T3-E1 cells. In conclusion, the PLGA/TCP/Mg scaffolds could inhibit bacterial adhesion and biofilm formation, and the PT10M scaffold was considered to be an effective composition with considerable antibacterial ability and good cytocompatibility.
doi:10.1038/srep13775
PMCID: PMC4561899  PMID: 26346217
15.  Expression of p53, p21 CIP1/WAF1 and eIF4E in the adjacent tissues of oral squamous cell carcinoma: establishing the molecular boundary and a cancer progression model 
The present study evaluated the expression of key molecules and the status of DNA in both oral squamous cell carcinoma (OSCC) and adjacent tissues to establish a molecular surgical boundary and provide a cancer progression model. Biopsy samples from 50 OSCC patients were divided into T (cancer), P1 (0–0.5 cm), P2 (0.5–1 cm), P3 (1–1.5 cm) and P4 (1.5–2 cm) groups based on the distances from the visible boundary of the primary focus. Twenty samples of normal mucosa were used as controls. We used immunohistochemical staining and flow cytometry to evaluate p53, p21 CIP1/WAF1 , eIF4E and Ki-67 expression and to determine DNA status, respectively. Sub-mucosal invasion was present in the P1 and P2 groups as determined by haematoxylin and eosin staining. Mutant p53 expression decreased gradually from cancerous to normal mucosae, whereas p21 CIP1/WAF1 expression displayed an opposite trend. eIF4E expression decreased from cancerous to normal mucosae. Ki-67 expression, the heteroploidy ratio, S-phase fraction and proliferative index decreased gradually with the distance from the tumour centre. Based on these results, we suggest that the resection boundary in OSCC surgery should be beyond 2 cm from the tumour. Additionally, the adjacent tissues of the primary focus could be used as a model for assessing cancer progression.
doi:10.1038/ijos.2015.5
PMCID: PMC4582560  PMID: 25835715
eIF4E; molecular boundary; oral squamous cell carcinoma; p21; p53
16.  Potential analgesic effects of a novel N-acylethanolamine acid amidase inhibitor F96 through PPAR-α 
Scientific Reports  2015;5:13565.
Pharmacological blockade of N-acylethanolamine acid amidase (NAAA) activity is an available approach for inflammation and pain control through restoring the ability of endogenous PEA. But the recently reported NAAA inhibitors suffer from the chemical and biological unstable properties, which restrict functions of NAAA inhibition in vivo. It is still unrevealed whether systematic inhibition of NAAA could modulate PEA-mediated pain signalings. Here we reported an oxazolidinone imide compound 3-(6-phenylhexanoyl) oxazolidin-2-one (F96), which potently and selectively inhibited NAAA activity (IC50 = 270 nM). Intraperitoneal (i.p.) injection of F96 (3–30 mg/kg) dose-dependently reduced ear edema and restored PEA levels of ear tissues in 12-O-Tetradecanoylphorbol-13-acetate (TPA) induced ear edema models. Furthermore, F96 inhibited acetic acid-induced writhing and increased spared nerve injury induced tactile allodynia thresholds in a dose-dependent manner. Pharmacological effects of F96 (10 mg/kg, i.p.) on various animal models were abolished in PPAR-α−/− mice, and were prevented by PPAR-α antagonist MK886 but not by canabinoid receptor type 1 (CB1) antagonist Rimonabant nor canabinoid receptor type 2 (CB2) antagonist SR144528. Zebrafish embryos experiments showed better security and lower toxicity for F96 than ibuprofen. These results revealed that F96 might be useful in treating inflammatory and neuropathic pain by NAAA inhibition depending on PPAR-α receptors.
doi:10.1038/srep13565
PMCID: PMC4550851  PMID: 26310614
17.  EGFR Modulates DNA Synthesis and Repair through Tyr Phosphorylation of Histone H4 
Developmental cell  2014;30(2):224-237.
Summary
Posttranslational modifications of histones play fundamental roles in many biological functions. Specifically, histone H4-K20 methylation is critical in DNA synthesis and repair. However, little is known about how these functions are regulated by the upstream stimuli. Here, we identify a tyrosine phosphorylation site at Y72 of histone H4, which facilitates recruitment of histone methyltransferases (HMTases), SET8 and SUV4-20H, to enhance its K20 methylation, thereby promoting DNA synthesis and repair. Phosphorylation-defective histone H4 mutant is deficient in K20 methylation, leading to reduced DNA synthesis, delayed cell cycle progression, and decreased DNA repair ability. Disrupting the interaction between epidermal growth factor receptor (EGFR) and histone H4 by Y72 peptide significantly reduced tumor growth. Furthermore, EGFR expression clinically correlates with histone H4-Y72 phosphorylation, H4-K20 mono-methylation, and the Ki-67 proliferation marker. These findings uncover a mechanism by which EGFR transduces signal to chromatin to regulate DNA synthesis and repair.
doi:10.1016/j.devcel.2014.06.008
PMCID: PMC4149291  PMID: 25073158
18.  Tumor-Selective, Futile Redox Cycle-Induced Bystander Effects Elicited by NQO1 Bioactivatable Radiosensitizing Drugs in Triple-Negative Breast Cancers 
Antioxidants & Redox Signaling  2014;21(2):237-250.
Abstract
Aims: β-Lapachone (β-lap), a novel radiosensitizer with potent antitumor efficacy alone, selectively kills solid cancers that over-express NAD(P)H:quinone oxidoreductase 1 (NQO1). Since breast or other solid cancers have heterogeneous NQO1 expression, therapies that reduce the resistance (e.g., NQO1low) of tumor cells will have significant clinical advantages. We tested whether NQO1-proficient (NQO1+) cells generated sufficient hydrogen peroxide (H2O2) after β-lap treatment to elicit bystander effects, DNA damage, and cell death in neighboring NQO1low cells. Results: β-Lap showed NQO1-dependent efficacy against two triple-negative breast cancer (TNBC) xenografts. NQO1 expression variations in human breast cancer patient samples were noted, where ∼60% cancers over-expressed NQO1, with little or no expression in associated normal tissue. Differential DNA damage and lethality were noted in NQO1+ versus NQO1-deficient (NQO1−) TNBC cells and xenografts after β-lap treatment. β-Lap-treated NQO1+ cells died by programmed necrosis, whereas co-cultured NQO1− TNBC cells exhibited DNA damage and caspase-dependent apoptosis. NQO1 inhibition (dicoumarol) or H2O2 scavenging (catalase [CAT]) blocked all responses. Only NQO1− cells neighboring NQO1+ TNBC cells responded to β-lap in vitro, and bystander effects correlated well with H2O2 diffusion. Bystander effects in NQO1− cells in vivo within mixed 50:50 co-cultured xenografts were dramatic and depended on NQO1+ cells. However, normal human cells in vitro or in vivo did not show bystander effects, due to elevated endogenous CAT levels. Innovation and Conclusions: NQO1-dependent bystander effects elicited by NQO1 bioactivatable drugs (β-lap or deoxynyboquinone [DNQ]) likely contribute to their efficacies, killing NQO1+ solid cancer cells and eliminating surrounding heterogeneous NQO1low cancer cells. Normal cells/tissue are protected by low NQO1:CAT ratios. Antioxid. Redox Signal. 21, 237–250.
doi:10.1089/ars.2013.5462
PMCID: PMC4060774  PMID: 24512128
19.  Phosphorylation of EZH2 at T416 by CDK2 contributes to the malignancy of triple negative breast cancers 
Triple-negative breast cancer (TNBC), which is closely related to basal-like breast cancer, is a highly aggressive subtype of breast cancer that initially responds to chemotherapy but eventually develops resistance. This presents a major clinical challenge as there are currently no effective targeted therapies available due to its lack of HER2 and estrogen receptor expression. Here, we show that cyclin E and the enhancer of zeste 2 (EZH2) are closely co-expressed in TNBC patients, and cyclin E/CDK2 phosphorylates EZH2 at T416 (pT416-EZH2) in vivo. Phosphorylation of EZH2 at T416 enhances the ability of EZH2 to promote TNBC cell migration/invasion, tumorsphere formation, and in vivo tumor growth. In addition, high pT416-EZH2 correlates with poorer survival in TNBC patients. These findings suggest that pT416 has the potential to serve as a therapeutic biomarker for the aggressive forms of breast cancer and provide a rationale for the use of CDK2 inhibitors to treat TNBC.
PMCID: PMC4532735  PMID: 26279746
CDK2; EZH2; phosphorylation
20.  Genome-Wide Analysis of the AP2/ERF Transcription Factors Family and the Expression Patterns of DREB Genes in Moso Bamboo (Phyllostachys edulis) 
PLoS ONE  2015;10(5):e0126657.
The AP2/ERF transcription factor family, one of the largest families unique to plants, performs a significant role in terms of regulation of growth and development, and responses to biotic and abiotic stresses. Moso bamboo (Phyllostachys edulis) is a fast-growing non-timber forest species with the highest ecological, economic and social values of all bamboos in Asia. The draft genome of moso bamboo and the available genomes of other plants provide great opportunities to research global information on the AP2/ERF family in moso bamboo. In total, 116 AP2/ERF transcription factors were identified in moso bamboo. The phylogeny analyses indicated that the 116 AP2/ERF genes could be divided into three subfamilies: AP2, RAV and ERF; and the ERF subfamily genes were divided into 11 groups. The gene structures, exons/introns and conserved motifs of the PeAP2/ERF genes were analyzed. Analysis of the evolutionary patterns and divergence showed the PeAP2/ERF genes underwent a large-scale event around 15 million years ago (MYA) and the division time of AP2/ERF family genes between rice and moso bamboo was 15–23 MYA. We surveyed the putative promoter regions of the PeDREBs and showed that largely stress-related cis-elements existed in these genes. Further analysis of expression patterns of PeDREBs revealed that the most were strongly induced by drought, low-temperature and/or high salinity stresses in roots and, in contrast, most PeDREB genes had negative functions in leaves under the same respective stresses. In this study there were two main interesting points: there were fewer members of the PeDREB subfamily in moso bamboo than in other plants and there were differences in DREB gene expression profiles between leaves and roots triggered in response to abiotic stress. The information produced from this study may be valuable in overcoming challenges in cultivating moso bamboo.
doi:10.1371/journal.pone.0126657
PMCID: PMC4436012  PMID: 25985202
21.  Genotyping analysis of 3 RET polymorphisms demonstrates low somatic mutation rate in Chinese Hirschsprung disease patients 
Background: Genetic mosaicism has been reported for both coding and non-coding sequences in the RET gene in Hirschsprung disease (HSCR) patients. This study aimed to investigate somatic mutation rate in Chinese population by comparing both homozygous genotype percentage and risk allele frequency of 3 RET single nucleotide polymorphisms (SNPs) among blood and colon samples. Methods: DNA was extracted from 59 HSCR blood samples, 59 control blood samples and 76 fresh frozen colon tissue samples (grouped into ganglionic, transitional and aganglionic level). Genotype status of rs2435357 and rs2506030 was examined by competitive allele specific hydrolysis probes (Taqman) PCR technology, and rs2506004 was examined by Sanger sequencing. Homozygous genotype percentage and risk allele frequency were calculated for each type of sample and compared by chi-square test. P<0.05 was regarded as being statistically significant. Results: Colon tissue DNA samples showed similar frequency of SNPs as that of the blood DNA samples in HSCR patients, both of which are significantly higher than the control blood group (rs2435357 TT genotype: 71.2%, 74.7% versus 22.0% in HSCR blood, HSCR colon and control blood DNA respectively, P=0.000; rs2506004 AA genotype: 72.4%, 83.1% versus 25.5%, P=0.000; rs2506030 GG genotype: 79.7%, 77.2% versus 54.2%, P=0.000 and 0.004). With respect to DNA extracted from ganglionic, transitional and aganglionic levels, no statistically significant difference was demonstrated in those 3 regions (rs2435357: P=0.897; rs2506004: P=0.740; rs2506030: P=0.901). Conclusion: Our data does not support the notion that high frequency of somatic changes as an underlying etiology of Chinese HSCR population.
PMCID: PMC4503131  PMID: 26191260
Hirschsprung disease; genetic mosaicism; RET proto-oncogene; fresh frozen colon
22.  Inducing gene expression by targeting promoter sequences using small activating RNAs 
Vector-based systems comprised of exogenous nucleic acid sequences remain the standard for ectopic expression of a particular gene. Such systems offer robust overexpression, but have inherent drawbacks such as the tedious process of construction, excluding sequences (e.g. introns and untranslated regions) important for gene function and potential insertional mutagenesis of host genome associated with the use of viral vectors. We and others have recently reported that short double-stranded RNAs (dsRNAs) can induce endogenous gene expression by targeting promoter sequences in a phenomenon referred to as RNA activation (RNAa) and such dsRNAs are termed small activating RNAs (saRNAs). To date, RNAa has been successfully utilized to induce the expression of different genes such as tumor suppressor genes. Here, we describe a detailed protocol for target selection and dsRNA design with associated experiments to facilitate RNAa in cultured cells. This technique may be applied to selectively activate endogenous gene expression for studying gene function, interrogating molecular pathways and reprogramming cell fate.
doi:10.14440/jbm.2015.39
PMCID: PMC4379447  PMID: 25839046
RNAa; saRNA; transcriptional activation; gene regulation
23.  Asymmetric Synthesis and Evaluation of Danshensu-Cysteine Conjugates as Novel Potential Anti-Apoptotic Drug Candidates 
We have previously reported that the danshensu-cysteine conjugate N-((R)-3-benzylthio-1-methoxy-1-oxo-2-propanyl)-2-acetoxy-3-(3,4-diacetoxyphenyl) propanamide (DSC) is a potent anti-oxidative and anti-apoptotic agent. Herein, we further design and asymmetrically synthesize two diastereoisomers of DSC and explore their potential bioactivities. Our results show that DSC and its two diastereoisomers exert similar protective effects in hydrogen peroxide (H2O2)-induced cellular injury in SH-SY5Y cells, as evidenced by the increase of cell viability, superoxide dismutase (SOD), and reduced glutathione (GSH) activity, and glutathione peroxidase (GPx) expression, and the decrease of cellular morphological changes and nuclear condensation, lactate dehydrogenase (LDH) release, and malondialdehyde (MDA) production. In H2O2-stimulated human umbilical vein endothelial cells (HUVEC), DSC concentration-dependently attenuates H2O2-induced cell death, LDH release, mitochondrial membrane potential collapse, and modulates the expression of apoptosis-related proteins (Bcl-2, Bax, caspase-3, and caspase-9). Our results provide strong evidence that DSC and its two diastereoisomers have similar anti-oxidative activity and that DSC exerts significant vascular-protective effects, at least in part, through inhibition of apoptosis and modulation of endogenous antioxidant enzymes.
doi:10.3390/ijms16010628
PMCID: PMC4307265  PMID: 25551606
Danshensu derivative; apoptosis; asymmetric synthesis; endothelial cells
24.  Gadd45b is a Novel Mediator of Neuronal Apoptosis in Ischemic Stroke 
Apoptosis plays an essential role in ischemic stroke pathogenesis. Research on the process of neuronal apoptosis in models of ischemic brain injury seems promising. The role of growth arrest and DNA-damage-inducible protein 45 beta (Gadd45b) in brain ischemia has not been fully examined to date. This study aims to investigate the function of Gadd45b in ischemia-induced apoptosis. Adult male Sprague-Dawley rats were subjected to brain ischemia by middle cerebral artery occlusion (MCAO). RNA interference (RNAi) system, which is mediated by a lentiviral vector (LV), was stereotaxically injected into the ipsilateral lateral ventricle to knockdown Gadd45b expression. Neurologic scores and infarct volumes were assessed 24 h after reperfusion. Apoptosis-related molecules were studied using immunohistochemistry and Western blot analysis. We found that Gadd45b-RNAi significantly increased infarct volumes and worsened the outcome of transient focal cerebral ischemia. Gadd45b-RNAi also significantly increased neuronal apoptosis as indicated by increased levels of Bax and active caspase-3, and decreased levels of Bcl-2. These results indicate that Gadd45b is a beneficial mediator of neuronal apoptosis.
doi:10.7150/ijbs.9813
PMCID: PMC4323375  PMID: 25678854
MCAO; Gadd45b; BDNF; Apoptosis
25.  Drosophila Syd-1, Liprin-α, and Protein Phosphatase 2A B′ Subunit Wrd Function in a Linear Pathway to Prevent Ectopic Accumulation of Synaptic Materials in Distal Axons 
The Journal of Neuroscience  2014;34(25):8474-8487.
During synaptic development, presynaptic differentiation occurs as an intrinsic property of axons to form specialized areas of plasma membrane [active zones (AZs)] that regulate exocytosis and endocytosis of synaptic vesicles. Genetic and biochemical studies in vertebrate and invertebrate model systems have identified a number of proteins involved in AZ assembly. However, elucidating the molecular events of AZ assembly in a spatiotemporal manner remains a challenge. Syd-1 (synapse defective-1) and Liprin-α have been identified as two master organizers of AZ assembly. Genetic and imaging analyses in invertebrates show that Syd-1 works upstream of Liprin-α in synaptic assembly through undefined mechanisms. To understand molecular pathways downstream of Liprin-α, we performed a proteomic screen of Liprin-α-interacting proteins in Drosophila brains. We identify Drosophila protein phosphatase 2A (PP2A) regulatory subunit B′ [Wrd (Well Rounded)] as a Liprin-α-interacting protein, and we demonstrate that it mediates the interaction of Liprin-α with PP2A holoenzyme and the Liprin-α-dependent synaptic localization of PP2A. Interestingly, loss of function in syd-1, liprin-α, or wrd shares a common defect in which a portion of synaptic vesicles, dense-core vesicles, and presynaptic cytomatrix proteins ectopically accumulate at the distal, but not proximal, region of motoneuron axons. Strong genetic data show that a linear syd-1/liprin-α/wrd pathway in the motoneuron antagonizes glycogen synthase kinase-3β kinase activity to prevent the ectopic accumulation of synaptic materials. Furthermore, we provide data suggesting that the syd-1/liprin-α/wrd pathway stabilizes AZ specification at the nerve terminal and that such a novel function is independent of the roles of syd-1/liprin-α in regulating the morphology of the T-bar structural protein BRP (Bruchpilot).
doi:10.1523/JNEUROSCI.0409-14.2014
PMCID: PMC4061390  PMID: 24948803
active zone assembly; Drosophila; Liprin-alpha; PP2A; presynaptic differentiation; Syd-1

Results 1-25 (146)