Publications by authors named "Xingliang Liu"

30 Publications

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Complementary Sequential Circulating Tumor Cell (CTC) and Cell-Free Tumor DNA (ctDNA) Profiling Reveals Metastatic Heterogeneity and Genomic Changes in Lung Cancer and Breast Cancer.

Front Oncol 2021 16;11:698551. Epub 2021 Jul 16.

Division of Medical Oncology, National Cancer Center, Singapore, Singapore.

Introduction: Circulating tumor cells (CTCs) and cell-free tumor DNA (ctDNA) are tumor components present in circulation. Due to the limited access to both CTC enrichment platforms and ctDNA sequencing in most laboratories, they are rarely analyzed together.

Methods: Concurrent isolation of ctDNA and single CTCs were isolated from lung cancer and breast cancer patients using the combination of size-based and CD45-negative selection method DropCell platform. We performed targeted amplicon sequencing to evaluate the genomic heterogeneity of CTCs and ctDNA in lung cancer and breast cancer patients.

Results: Higher degrees of genomic heterogeneity were observed in CTCs as compared to ctDNA. Several shared alterations present in CTCs and ctDNA were undetected in the primary tumor, highlighting the intra-tumoral heterogeneity of tumor components that were shed into systemic circulation. Accordingly, CTCs and ctDNA displayed higher degree of concordance with the metastatic tumor than the primary tumor. The alterations detected in circulation correlated with worse survival outcome for both lung and breast cancer patients emphasizing the impact of the metastatic phenotype. Notably, evolving genetic signatures were detected in the CTCs and ctDNA samples during the course of treatment and disease progression.

Conclusions: A standardized sample processing and data analysis workflow for concurrent analysis of CTCs and ctDNA successfully dissected the heterogeneity of metastatic tumor in circulation as well as the progressive genomic changes that may potentially guide the selection of appropriate therapy against evolving tumor clonality.
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http://dx.doi.org/10.3389/fonc.2021.698551DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8322849PMC
July 2021

Topical cationic hairy particles targeting cell free DNA in dermis enhance treatment of psoriasis.

Biomaterials 2021 Sep 15;276:121027. Epub 2021 Jul 15.

School of Materials Science and Engineering, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, GD Research Center for Functional Biomaterials Engineering and Technology, Sun Yat-sen University, 510275, Guangzhou, China. Electronic address:

Abnormal high level of cell free DNA (cfDNA) triggers chronic inflammation to exacerbate psoriasis symptoms. Scavenging cfDNA by topical cationic polymeric nanoparticles has been certified as an effective therapeutic strategy for treating psoriasis. However, cationic cfDNA scavengers have a great potential risk to organs after entering systemic circulation through skin barrier. For better transformation to clinical application, herein a series of poly(2-(dimethylamino)ethyl methacrylate) (PDMA) grafted hairy silica particles (cSPs) with tunable PDMA length and particle size are applied to scavenge cfDNA in dermis. We reveal that the structure of cSPs correlates with the permeation ability across stratum corneum, retention time in dermis, binding affinity to cfDNA, and toxicity tolerance, which in turn affect the therapeutic effect. Especially, the cSPs of 700 nm show more accumulation and longer retention in psoriatic lesions, leading to excellent treatment results. They also outperform the cSPs of 200 nm at a lower administration frequency. Thus, we address the issues of size, cationic content of cSPs to open a potential new avenue to topically treatment of psoriasis by targeting cfDNA in dermis.
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http://dx.doi.org/10.1016/j.biomaterials.2021.121027DOI Listing
September 2021

Nutrient trade-offs mediated by ectomycorrhizal strategies in plants: Evidence from an species in subalpine forests.

Ecol Evol 2021 May 16;11(10):5281-5294. Epub 2021 Mar 16.

School of Ecology and Nature Conservation Beijing Forestry University Beijing China.

Ectomycorrhizal (ECM) symbiosis is an evolutionary biological trait of higher plants for effective nutrient uptakes. However, little is known that how the formation and morphological differentiations of ECM roots mediate the nutrients of below- and aboveground plant tissues and the balance among nutrient elements across environmental gradients. Here, we investigated the effects of ECM foraging strategies on root and foliar N and P concentrations and N:P ratio under variations of climate and soil conditions.The ECM symbionts preferentially mediated P uptake under both N and P limitations. The uptake efficiency of N and P was primarily associated with the ECM root traits, for example, ECM root tip density, superficial area of ECM root tips, and the ratio of living to dead root tips, and was affected by the ECM proliferations and morphological differentiations. The tissue N and P concentrations were positively associated with the abundance of the contact exploration type and negatively with that of the short-distance exploration type.Our findings indicate that the nutritional status of both below- and aboveground plant tissues can be strongly affected by ECM symbiosis in natural environments. Variations in the ECM strategies in response to varying environmental conditions significantly influence plant nutrient uptakes and trade-offs.
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http://dx.doi.org/10.1002/ece3.7417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8131813PMC
May 2021

An integrative model of pathway convergence in genetically heterogeneous blast crisis chronic myeloid leukemia.

Blood 2020 06;135(26):2337-2353

Cancer Therapeutics & Stratified Oncology, Genome Institute of Singapore, Singapore.

Targeted therapies against the BCR-ABL1 kinase have revolutionized treatment of chronic phase (CP) chronic myeloid leukemia (CML). In contrast, management of blast crisis (BC) CML remains challenging because BC cells acquire complex molecular alterations that confer stemness features to progenitor populations and resistance to BCR-ABL1 tyrosine kinase inhibitors. Comprehensive models of BC transformation have proved elusive because of the rarity and genetic heterogeneity of BC, but are important for developing biomarkers predicting BC progression and effective therapies. To better understand BC, we performed an integrated multiomics analysis of 74 CP and BC samples using whole-genome and exome sequencing, transcriptome and methylome profiling, and chromatin immunoprecipitation followed by high-throughput sequencing. Employing pathway-based analysis, we found the BC genome was significantly enriched for mutations affecting components of the polycomb repressive complex (PRC) pathway. While transcriptomically, BC progenitors were enriched and depleted for PRC1- and PRC2-related gene sets respectively. By integrating our data sets, we determined that BC progenitors undergo PRC-driven epigenetic reprogramming toward a convergent transcriptomic state. Specifically, PRC2 directs BC DNA hypermethylation, which in turn silences key genes involved in myeloid differentiation and tumor suppressor function via so-called epigenetic switching, whereas PRC1 represses an overlapping and distinct set of genes, including novel BC tumor suppressors. On the basis of these observations, we developed an integrated model of BC that facilitated the identification of combinatorial therapies capable of reversing BC reprogramming (decitabine+PRC1 inhibitors), novel PRC-silenced tumor suppressor genes (NR4A2), and gene expression signatures predictive of disease progression and drug resistance in CP.
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http://dx.doi.org/10.1182/blood.2020004834DOI Listing
June 2020

Green Hydrothermal Synthesis of N-doped Carbon Dots from Biomass Highland Barley for the Detection of Hg.

Sensors (Basel) 2019 Jul 18;19(14). Epub 2019 Jul 18.

Chemical Engineering College, Qinghai University, Xining 810016, China.

Totally water-soluble N-doped Carbon dots (N-CDs) were synthesized by a green hydrothermal method from biomass using Highland barley as a carbon source and ethanediamine as nitrogen source. TEM and XRD showed the graphitic amorphous structure and narrow diameter distribution of these N-CDs. N-doping to the crystal lattice and carrying many hydrophilic groups on the surface of N-CDs were verified by XPS and FT-IR. The as-synthesized N-CDs emitted strong blue fluorescence at 480 nm and owned a relatively high quantum yield of 14.4%. The product also could sensitively and selectively detect Hg ions in the range of 10-160 μM and the limit of detection was equal to 0.48 μM.
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http://dx.doi.org/10.3390/s19143169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679557PMC
July 2019

An aqueous fluorescent sensor for Pb based on phenothiazine-polyamide.

Spectrochim Acta A Mol Biomol Spectrosc 2018 Aug 30;201:193-196. Epub 2018 Apr 30.

Chemical Engineering College, Qinghai University, Xining 810016, Qinghai, China. Electronic address:

A sensitive and selective fluorescent sensor for Pb ion based on phenothiazine-polyamide was built (named sensor PP). Due to introducing of four diethanolamine groups to polyamide, this sensor was totally water soluble. PP could detect Pb ion within 1 min in the presence of other metal ions in aqueous solution, the detect limit was 9.11 × 10 M.
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http://dx.doi.org/10.1016/j.saa.2018.04.063DOI Listing
August 2018

Elucidating the genomic architecture of Asian EGFR-mutant lung adenocarcinoma through multi-region exome sequencing.

Nat Commun 2018 01 15;9(1):216. Epub 2018 Jan 15.

Cancer Stem Cell Biology, Genome Institute of Singapore, Singapore, 138672, Singapore.

EGFR-mutant lung adenocarcinomas (LUAD) display diverse clinical trajectories and are characterized by rapid but short-lived responses to EGFR tyrosine kinase inhibitors (TKIs). Through sequencing of 79 spatially distinct regions from 16 early stage tumors, we show that despite low mutation burdens, EGFR-mutant Asian LUADs unexpectedly exhibit a complex genomic landscape with frequent and early whole-genome doubling, aneuploidy, and high clonal diversity. Multiple truncal alterations, including TP53 mutations and loss of CDKN2A and RB1, converge on cell cycle dysregulation, with late sector-specific high-amplitude amplifications and deletions that potentially beget drug resistant clones. We highlight the association between genomic architecture and clinical phenotypes, such as co-occurring truncal drivers and primary TKI resistance. Through comparative analysis with published smoking-related LUAD, we postulate that the high intra-tumor heterogeneity observed in Asian EGFR-mutant LUAD may be contributed by an early dominant driver, genomic instability, and low background mutation rates.
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http://dx.doi.org/10.1038/s41467-017-02584-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5768770PMC
January 2018

A Ratiometric Fluorescent Sensor for Cd Based on Internal Charge Transfer.

Sensors (Basel) 2017 Nov 2;17(11). Epub 2017 Nov 2.

Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84108, USA.

This work reports on a novel fluorescent sensor for Cd ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1-pyrrol-2-yl)methylene]hydrazine (Me₄BOPHY), which is modified with an electron donor moiety of ,-bis(pyridin-2-ylmethyl)benzenamine. Sensor has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT) transition of molecule . Binding of Cd ion quenches the ICT transition, but turns on the π - π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD) was projected down to 0.77 ppb, which is far below the safety value (3 ppb) set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd in comparison to other interferent metal ions.
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http://dx.doi.org/10.3390/s17112517DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5713183PMC
November 2017

Molecular characterization of circulating colorectal tumor cells defines genetic signatures for individualized cancer care.

Oncotarget 2017 Sep 10;8(40):68026-68037. Epub 2017 Jul 10.

Genome Institute of Singapore, Singapore 138672, Singapore.

Studies on circulating tumor cells (CTCs) have largely focused on platform development and CTC enumeration rather than on the genomic characterization of CTCs. To address this, we performed targeted sequencing of CTCs of colorectal cancer patients and compared the mutations with the matched primary tumors. We collected preoperative blood and matched primary tumor samples from 48 colorectal cancer patients. CTCs were isolated using a label-free microfiltration device on a silicon microsieve. Upon whole genome amplification, we performed amplicon-based targeted sequencing on a panel of 39 druggable and frequently mutated genes on both CTCs and fresh-frozen tumor samples. We developed an analysis pipeline to minimize false-positive detection of somatic mutations in amplified DNA. In 60% of the CTC-enriched blood samples, we detected primary tumor matching mutations. We found a significant positive correlation between the allele frequencies of somatic mutations detected in CTCs and abnormal CEA serum level. Strikingly, we found driver mutations and amplifications in cancer and druggable genes such as , and . In addition, we found that CTCs carried mutation signatures that resembled the signatures of their primary tumors. Cumulatively, our study defined genetic signatures and somatic mutation frequency of colorectal CTCs. The identification of druggable mutations in CTCs of preoperative colorectal cancer patients could lead to more timely and focused therapeutic interventions.
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http://dx.doi.org/10.18632/oncotarget.19138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5620233PMC
September 2017

A Cu-Selective Probe Based on Phenanthro-Imidazole Derivative.

Sensors (Basel) 2016 Dec 24;17(1). Epub 2016 Dec 24.

Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112, USA.

A novel fluorescent Probe , based on phenanthro-imidazole has been developed as an efficient chemosensor for the trace detection of copper ions (Cu). Probe demonstrated sensitive fluorescence quenching upon binding with Cu through 1:1 stoichiometric chelation. The detection limit for Cu ions was projected through linear quenching fitting to be as low as 2.77 × 10 M (or 1.77 ppb). The sensing response was highly selective towards Cu with minimal influence from other common metal ions, facilitating the practical application of Probe in trace detection.
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http://dx.doi.org/10.3390/s17010035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5298608PMC
December 2016

One-step reverse transcription loop-mediated isothermal amplification for the detection of Maize chlorotic mottle virus in maize.

J Virol Methods 2017 02 27;240:49-53. Epub 2016 Nov 27.

State Key Laboratory of Agro-biotechnology and Ministry of Agriculture Key Laboratory for Plant Pathology, China Agricultural University, Beijing 100193, China. Electronic address:

Maize chlorotic mottle virus (MCMV) is spreading in many regions worldwide, causing maize lethal necrosis when co-infected with a potyvirid. In this study, one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to detect MCMV in maize. A set of four specific primers was designed based on the conserved coat protein gene sequences of MCMV. The RT-LAMP could be completed within 60min under isothermal condition at 63°C. The sensitivity test showed that the RT-LAMP was about 10-fold more sensitive than RT-PCR and no cross-reactivity was detected with other viral pathogens infecting maize in China. Moreover, the results of RT-LAMP could be visually inspected by SYBR Green I staining in a closed-tube, facilitating high-throughput application of MCMV detection. This method was further verified by testing field-collected samples. These results suggested that the developed MCMV RT-LAMP technique is a rapid, efficient and sensitive method which could be used as a routine screen for MCMV infection.
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http://dx.doi.org/10.1016/j.jviromet.2016.11.012DOI Listing
February 2017

Soil respiration and its environmental response varies by day/night and by growing/dormant season in a subalpine forest.

Sci Rep 2016 11 29;6:37864. Epub 2016 Nov 29.

Sichuan Engineering Consulting and Research Institute, 201 Yu Sha Road Xinhua Avenue, Chengdu, 610016, Sichuan, China.

Comparisons of soil respiration (R) and its components of heterotrophic (R) and rhizospheric (R) respiration during daytime and nighttime, growing (GS) and dormant season (DS), have not being well studied and documented. In this study, we compared R, R, R, and their responses to soil temperature (T) and moisture (θ) in daytime vs. nighttime and GS vs. DS in a subalpine forest in 2011. In GS, nighttime R and R rates were 30.5 ± 4.4% (mean ± SE) and 30.2 ± 6.5% lower than in daytime, while in DS, they were 35.5 ± 5.5% and 37.3 ± 8.5% lower, respectively. DS R and R accounted for 27.3 ± 2.5% and 27.6 ± 2.6% of GS R and R, respectively. The temperature sensitivities (Q) of R and R were higher in nighttime than daytime, and in DS than GS, while they all decreased with increase of T. Soil C fluxes were more responsive to θ in nighttime than daytime, and in DS than GS. Our results suggest that the DS and nighttime R play an important role in regulating carbon cycle and its response to climate change in alpine forests, and therefore, they should be taken into consideration in order to make accurate predictions of R and ecosystem carbon cycle under climate change scenarios.
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http://dx.doi.org/10.1038/srep37864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5126676PMC
November 2016

β-Furan-Fused bis(Difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine Fluorescent Dyes in the Visible Deep-Red Region.

J Org Chem 2016 09 5;81(17):7439-47. Epub 2016 Aug 5.

Chemical Engineering College, Qinghai University , Xining 810016, China.

Novel β-furan-fused bis(difluoroboron)-1,2-bis((1H-pyrrol-2-yl)methylene)hydrazine (BOPHY) fluorescent dyes (F-BOPHY1-3) were prepared through an efficient process, and their structures were confirmed by (1)H NMR spectroscopy, (13)C NMR spectroscopy, MALDI-TOF HRMS, and element analysis. Their optical properties were then characterized by UV-vis absorption and photoluminescence (PL) spectroscopy. The UV-vis absorption and PL spectra of the dyes shifted to longer wavelengths relative to those of BOPHY because of the fusion of their furan rings, which extended π-conjugation of the molecules. All of the dyes exhibited large extinction coefficients (109700-12300 M(-1) cm(-1)), deep-red fluorescence emission (646-667 nm), moderate fluorescence quantum yields (0.30-0.45), as well as high chemical stability and photostability in solution. These advantageous properties show that these compounds are important to the design of efficient long-wavelength fluorescent dyes and are suitable for various applications in biotechnology and materials science.
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http://dx.doi.org/10.1021/acs.joc.6b01018DOI Listing
September 2016

A Fluorescent Sensor Synthesized Using Silica Nanoparticles for Detecting Hg²⁺ in Aqueous Solution.

J Nanosci Nanotechnol 2016 Jan;16(1):753-7

With the aim of detecting Hg²⁺ in aqueous solution, a new fluorescent nanosensor (RhB-APTES-SiNPs) for the determination of Hg²⁺ has been successfully developed. This senor was synthesized by immobilizing RhB-APTES on the surface of silica nanoparticles (SiNPs), which were prepared using the reverse microemulsion method. RhB-APTES-SiNPs can detect Hg²⁺ on-line, in real time and with the naked eye, thus providing "turn-on" fluorescence enhancement. The developed nanosensor exhibits highly sensitivity and selectivity over several cations in aqueous solution. Additionally, RhB-APTES-SiNPs exhibits an excellent ability to detect Hg²⁺ within a linear range from 1 to 6 µM, and its detection limit was calculated to be 0.5 ppb.
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http://dx.doi.org/10.1166/jnn.2016.11123DOI Listing
January 2016

Differential Expression between Human Dermal Papilla Cells from Balding and Non-Balding Scalps Reveals New Candidate Genes for Androgenetic Alopecia.

J Invest Dermatol 2016 08 7;136(8):1559-1567. Epub 2016 Apr 7.

Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore, Singapore. Electronic address:

Androgenetic alopecia (AGA) is a common heritable and androgen-dependent hair loss condition in men. Twelve genetic risk loci are known to date, but it is unclear which genes at these loci are relevant for AGA. Dermal papilla cells (DPCs) located in the hair bulb are the main site of androgen activity in the hair follicle. Widely used monolayer-cultured primary DPCs in hair-related studies often lack dermal papilla characteristics. In contrast, immortalized DPCs have high resemblance to intact dermal papilla. We derived immortalized human DPC lines from balding (BAB) and non-balding (BAN) scalp. Both BAB and BAN retained high proportions of dermal papilla signature gene and versican protein expression. We performed expression analysis of BAB and BAN and annotated AGA risk loci with differentially expressed genes. We found evidence for AR but not EDA2R as the candidate gene at the AGA risk locus on chromosome X. Further, our data suggest TWIST1 (twist family basic helix-loop-helix transcription factor 1) and SSPN (sarcospan) to be the functionally relevant AGA genes at the 7p21.1 and 12p12.1 risk loci, respectively. Down-regulated genes in BAB compared to BAN were highly enriched for vasculature-related genes, suggesting that deficiency of DPC from balding scalps in fostering vascularization around the hair follicle may contribute to the development of AGA.
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http://dx.doi.org/10.1016/j.jid.2016.03.032DOI Listing
August 2016

The first complete genome sequence of iris severe mosaic virus.

Arch Virol 2016 Apr 5;161(4):1069-72. Epub 2016 Jan 5.

Chinese Society of Inspection and Quarantine, Beijing, 101312, China.

The first complete genome sequence of ISMV was determined by deep sequencing of a small RNA library constructed from ISMV-infected samples and rapid amplification of cDNA ends (RACE) PCR. The ISMV genome consists of 10,403 nucleotides excluding the poly(A) tail and contains a large open reading frame encoding a polyprotein of 3316 amino acids. Putative proteolytic cleavage sites were identified by BLAST analysis. The ISMV polyprotein showed highest amino acid sequence identity to that encoded by onion yellow dwarf virus. Phylogenetic analysis of the polyprotein amino acid sequence confirmed that ISMV forms a cluster with shallot yellow stripe virus, Cyrtanthus elatus virus A, narcissus degeneration virus and onion yellow dwarf virus. These results confirm that ISMV is a distinct member of the genus Potyvirus.
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http://dx.doi.org/10.1007/s00705-015-2743-1DOI Listing
April 2016

Characterization of siRNAs derived from cucumber green mottle mosaic virus in infected cucumber plants.

Arch Virol 2016 Feb 19;161(2):455-8. Epub 2015 Nov 19.

Chinese Society of Inspection and Quarantine, Beijing, 100029, China.

Virus-derived small interfering RNAs (vsiRNAs) of cucumber green mottle mosaic virus (CGMMV), a member of the genus Tobamovirus, were characterised in cucumber plants by deep sequencing. CGMMV vsiRNAs of 21-22 nt in length predominated, suggesting that there might be a conserved mechanism of DCL2 and DCL4 involvement in the biogenesis of vsiRNAs, as well as a common RNA silencing pathway in CGMMV-infected cucumber plants. The 5'-terminal base of vsiRNAs was biased towards C/A/U, suggesting that CGMMV vsiRNAs might be loaded into diverse AGO-containing RISCs to disturb the gene expression of host plants. Possible targets for some of the vsiRNAs were also predicted.
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http://dx.doi.org/10.1007/s00705-015-2687-5DOI Listing
February 2016

Recurrent Fusion Genes in Gastric Cancer: CLDN18-ARHGAP26 Induces Loss of Epithelial Integrity.

Cell Rep 2015 Jul 2;12(2):272-85. Epub 2015 Jul 2.

Département de Biologie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.

Genome rearrangements, a hallmark of cancer, can result in gene fusions with oncogenic properties. Using DNA paired-end-tag (DNA-PET) whole-genome sequencing, we analyzed 15 gastric cancers (GCs) from Southeast Asians. Rearrangements were enriched in open chromatin and shaped by chromatin structure. We identified seven rearrangement hot spots and 136 gene fusions. In three out of 100 GC cases, we found recurrent fusions between CLDN18, a tight junction gene, and ARHGAP26, a gene encoding a RHOA inhibitor. Epithelial cell lines expressing CLDN18-ARHGAP26 displayed a dramatic loss of epithelial phenotype and long protrusions indicative of epithelial-mesenchymal transition (EMT). Fusion-positive cell lines showed impaired barrier properties, reduced cell-cell and cell-extracellular matrix adhesion, retarded wound healing, and inhibition of RHOA. Gain of invasion was seen in cancer cell lines expressing the fusion. Thus, CLDN18-ARHGAP26 mediates epithelial disintegration, possibly leading to stomach H(+) leakage, and the fusion might contribute to invasiveness once a cell is transformed.
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http://dx.doi.org/10.1016/j.celrep.2015.06.020DOI Listing
July 2015

A multiplex RT-PCR for simultaneous detection and identification of five viruses and two viroids infecting chrysanthemum.

Arch Virol 2015 May 20;160(5):1145-52. Epub 2015 Feb 20.

Department of Biological Science, College of Life Sciences, Henan Normal University, Construction East Road No. 46, Muye District, Xinxiang, 453007, People's Republic of China.

Pathogens causing significant economic losses in chrysanthemum include tomato aspermy virus (TAV), chrysanthemum virus B (CVB), cucumber mosaic virus (CMV), tobacco mosaic virus (TMV), potato virus Y (PVY), chrysanthemum stunt viroid (CSVd) and chrysanthemum chlorotic mottle viroid (CChMVd). A multiplex reverse transcription polymerase chain reaction (RT-PCR) method, using specific primer sets for each virus or viroid, was developed for simultaneous detection and differentiation of TAV, CVB, CMV, TMV, PVY, CChMVd, and CSVd. The RT-PCR method was validated by testing chrysanthemum samples collected from different regions of China. In this study, CVB, TAV, TMV, PVY, CSVd, CMV, and CChMVd were detected, respectively, in 24.7 %, 17.5 %, 4.4 %, 4.4 %, 2.9 %, 2.5 %, and 1.5 % of the samples tested. These results indicate that CVB and TAV (24.7 % and 17.5 %) are common, whereas CMV, TMV, CChMVd, CSVd, and PVY (all below 5 %) are less frequently encountered. This new multiplex RT-PCR method has potential to be used routinely in large-scale virus and viroid surveys.
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http://dx.doi.org/10.1007/s00705-015-2360-zDOI Listing
May 2015

Synthesis and photophysical properties of phosphorus(V) porphyrins functionalized with axial carbazolylvinylnaphthalimides.

Org Biomol Chem 2012 Nov;10(43):8701-9

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.

We have synthesized new D-A-D type phosphorus(V) porphyrin derivatives and functionalized with axial carbazolylvinylnaphthalimide units. The absorption bands of the obtained phosphorus(V) porphyrins were in the range 250-640 nm with high molar absorption coefficients, meaning strong light-harvesting abilities. Notably, it is found that the devices based on phosphorus(V) porphyrins with a configuration structure of [ITO/PEDOT : PSS/organic active film/LiF/Al] give an incident-photon-to-current conversion efficiency (IPCE) response. The maximal IPCE value reaches 2.76% for the device based on compound , which is much higher than that of 0.20% for compound . The reason might be due to the low oxidation potential and the strong light-harvesting ability of the enlarged conjugation of the axial units in compound . Therefore, we deduced that photo-induced electron transfer happened in phosphorus(V) porphyrins bearing axial conjugated donor units, which would make them good candidates for photovoltaic materials that could be applied in solar cells.
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http://dx.doi.org/10.1039/c2ob26478aDOI Listing
November 2012

Identification of a UDP-glucose pyrophosphorylase from cotton (Gossypium hirsutum L.) involved in cellulose biosynthesis in Arabidopsis thaliana.

Plant Cell Rep 2011 Jul 5;30(7):1303-12. Epub 2011 Mar 5.

College of Science, China Agricultural University, 2 West Road, Yuanmingyuan, Haidian District, Beijing, China.

UDP-glucose pyrophosphorylase is an important regulatory enzyme for the development of plants and a critical enzyme in synthesis of glycogen. Here, we reported the cloning of a full-length UGP cDNA from cotton, named GhUGP. Real-time PCR analysis indicated the GhUGP expression in root, stem, leaf and flower of cotton, with a higher level in flower and root. The transcription level of GhUGP depended on sucrose and light in short time and increased under low temperature, but decreased in O(2) deficiency. Interestingly, the expression of GhUGP was significantly up-regulated after ethylene induction in cotton ovules. The over-expression of the GhUGP in Arabidopsis showed discrepant phenotype: increase in height and growth rate when compared with control lines. What is more, the transgenic Arabidopsis had increased contents of soluble sugars, starch and cellulose, but not in lignin content. Collectively, these results indicate that cotton UGPase participates in sucrose/polysaccharides metabolism and cell wall biosynthesis and provide theoretical deduction supporting GhUGP as a good candidate gene for improving the development of cotton fibers cell.
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http://dx.doi.org/10.1007/s00299-011-1042-xDOI Listing
July 2011

Luminescent organic 1D nanomaterials based on bis(β-diketone)carbazole derivatives.

Chemistry 2011 Feb 5;17(5):1660-9. Epub 2011 Jan 5.

Key Laboratory of Supramolecular Structure and Materials College of Chemistry, Jilin University, Changchun, P. R. China.

A series of new triphenylamine-functionalized bis(β-diketone)s bridged by a carbazole (CnBDKC, n=1, 4, 8, 16) with twisted intramolecular charge-transfer emission in polar solvents has been synthesized. The length of the carbon chains has a significant effect on the self-assembling properties of the compounds. Well-defined 1D nanowires were easily generated from C1BDKC with a methyl group by a reprecipitation approach directed by π-stacking interaction, and the molecules packed into J-aggregates in the nanowires. In addition, 1D nanofibers based on C16BDKC bearing a long hexadecyl chain were prepared through the organogelation process, and H-aggregates were formed driven by the synergistic effect of π-stacking interaction and van der Waals force in the gel phase. C4BDKC and C8BDKC containing butyl and octyl side chains, respectively, cannot arrange into dispersed nanostructures, probably because π-π interaction between conjugated moieties might be disturbed by the interaction between the side chains, which is, however, not strong enough to dominate the self-assembling process. Notably, the nanowires based on C1BDKC and the gel nanofibers from C16BDKC can emit strong green light under irradiation, which suggests that these 1D nanomaterials may have potential applications in emitting materials as well as photonic devices.
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http://dx.doi.org/10.1002/chem.201001858DOI Listing
February 2011

Synthesis of star-shaped monodisperse oligo(9,9-di-n-octylfluorene-2,7-vinylene)s functionalized truxenes with two-photon absorption properties.

Org Biomol Chem 2011 Mar 18;9(5):1600-7. Epub 2011 Jan 18.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.

A series of new star-shaped monodisperse conjugated truxene derivatives bearing oligo(fluorene-vinylene) arms (Tr-OFVn, n = 1, 2, 3, 4) have been synthesized. It is found that the conjugation of the oligomers can be extended with prolonging the arms. Notably, the branched oligomers Tr-OFVn without strong donor and acceptor units exhibit two-photon absorption properties, and the two-photon absorption cross sections (δ(max)) increase with increasing the number of fluorene-vinylene units in the arms. The maximum value of δ(max) reaches 8073 GM for compound Tr-OFV4, which made it one of the most competitive compounds with enhanced TPA cross section. It provides a new platform for exploiting strong TPA compounds, in which the extended π-conjugated systems are involved in the absence of strong donor and acceptor units.
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http://dx.doi.org/10.1039/c0ob00803fDOI Listing
March 2011

New dendritic gelator bearing carbazole in each branching unit: selected response to fluoride ion in gel phase.

Org Biomol Chem 2011 Mar 12;9(5):1523-8. Epub 2011 Jan 12.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, PR China.

A new dendritic gelator with carbazole as the building block (HBCD) was synthesized. It was found that H-bonding between the amide groups and π-π interaction between the aromatic rings played predominant roles in the gel formation. Meanwhile, significant aggregation-induced emission enhancement was observed in the gel state due to the formation of J-aggregates and the restricted molecular motion. Notably, the gel state of HBCD can be destroyed upon addition of F(-), accompanied by fluorescence enhancement on account of the formation of N-HF(-), which could further lead to the increased coplanarity of HBCD. The sensory capability of HBCD exhibited a high selectivity towards F(-) instead of the Cl(-), Br(-), I(-) and AcO(-) anions, which could be explained by the fact that the steric hindrance of the dendrimer would go against the interactions between the larger anions and HBCD.
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http://dx.doi.org/10.1039/c0ob00786bDOI Listing
March 2011

Organogel based on β-diketone-boron difluoride without alkyl chain and H-bonding unit directed by optimally balanced π-π interaction.

Chem Commun (Camb) 2010 Nov 11;46(44):8419-21. Epub 2010 Oct 11.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.

Rigid boomerang shaped triphenylamine functionalized bis-β-diketone-boron difluoride without alkyl chain and H-bonding unit exhibits good gelation ability in some mixed organic solvents directed by optimally balanced π-π interactions.
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http://dx.doi.org/10.1039/c0cc03448gDOI Listing
November 2010

Phenothiazine-based oligomers as novel fluorescence probes for detecting vapor-phase nitro compounds.

Talanta 2010 Oct 21;82(5):1943-9. Epub 2010 Aug 21.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.

To meet the need for rapid and low-cost chemical sensing of explosive, new fluorescence chemosensors based on oligophenothiazines for probing vapor-phase nitro compounds have been developed. The phenothiazine-based trimer P3 and pentamer P5 have been synthesized via Heck and Wittig reactions by convergent approach. It was found that they can detect the vapors of nitro compounds, including p-nitrotoluene (p-NT), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) with good sensitivity and reversibility. And the sensor of P3 film gave a linear fluorescence quenching response to 7-800 ppb TNT with the detection limit of 4 ppb. For DNT vapor, a linear working range of the sensor was 2-24 ppm with the detection limit of 40 ppb. Meanwhile, the interferents, including common organic solvents, p-nitrophenol and 2,4-dinitrophenylhydrazine cannot lead to obvious fluorescence quenching, meaning that the film based on oligophenothiazines exhibited good specificity of fluorescence response to explosive. Based on the fluorescence lifetime and UV-vis absorption measurements, we suggested that the fluorescence quenching of oligophenothiazine-based films exposed to the vapors of nitro compounds was due to the formation of non-fluorescent charge-transfer complex between oligophenothiazine and nitro compounds.
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http://dx.doi.org/10.1016/j.talanta.2010.08.016DOI Listing
October 2010

Multicolor fluorescent switches in gel systems controlled by alkoxyl chain and solvent.

Org Biomol Chem 2010 Oct 11;8(19):4289-96. Epub 2010 Aug 11.

Test Science Experiment Center, Jilin University, 2699 Qianjin Street, Changchun, 130012, PR China.

Two simple molecules, 1 and 2 with D-pi-A structure and alkoxyl groups, respectively, were designed and synthesized. Both compounds can gelatinize THF-water and DMSO. And compound 2 forms gel in acetone by ultrasonic stimulus. Interestingly, these gels exhibit aggregation-induced emission (AIE) during the sol-gel phase transformation. Moreover, the molecular self-assembled and photophysical properties can be controlled by the number of the alkoxyl chains and the type of the solvents. For example, 1 has an identical packing model and fluorescent colour in THF-water and DMSO gels. Contrarily, the self-assembly of molecule 2 strongly depends on the solvent. Furthermore, the gel phases of 2 formed in three solvents possess different fluorescent colours. Such as, THF-water gel emits yellow fluorescence, acetone gel has orange emission and red fluorescence appears in DMSO.
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http://dx.doi.org/10.1039/c0ob00091dDOI Listing
October 2010

Porphyrins with four monodisperse oligocarbazole arms: facile synthesis and photophysical properties.

J Org Chem 2008 Mar 30;73(5):1809-17. Epub 2008 Jan 30.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China.

A series of novel monodisperse, well-defined, star-shaped molecules T(OCAn)Ps (n = 2-6) with a central porphyrin core and four oligocarbazole arms are synthesized from the corresponding formyl-substituted oligocarbazoles via Adler reaction. The obtained star-shaped porphyrins are intrinsically two-dimensional nanosized molecules, and the diameter of compound T(OCA6)P is 7.4 nm, representing one of the largest known star-shaped conjugated systems. Their photophysical properties have been investigated by absorption and steady-state fluorescence spectroscopy, together with the corresponding monodisperse oligocarbazole aldehyde precursors. It is found that the light-harvesting capability of T(OCAn)Ps increases with the increasing length of the arms and reaches the maximum when n = 6. A selective excitation of the oligocarbazole arms leads to the typical emission from the porphyrin cores, indicating occurrence of photoinduced intramolecular energy transfer, and the energy transfer efficiency decreases from T(OCA2)P to T(OCA6)P owing to the Förster energy-transfer process. Accordingly, the longest effective distance for Förster energy transfer is estimated to be ca. 3 nm in our system. Such star-shaped porphyrins may find applications in photonic devices, with respect to their intense emission of red light. Notably, the monodisperse oligocarbazole aldehyde precursors give twisted intramolecular charge-transfer (TICT) excited states and luminescence in polar solvents with large Stokes shifts.
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http://dx.doi.org/10.1021/jo702426rDOI Listing
March 2008

Novel carbazole-based organogels modulated by tert-butyl moieties.

Chem Commun (Camb) 2008 Jan 28(4):453-5. Epub 2007 Nov 28.

State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, PR China.

tert-Butyl groups can modulate the self-assembling properties of carbazole derivatives; organogel fibers with a bright blue emission are generated, directed by the cooperation of hydrogen bonding as well as pi-pi interactions.
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http://dx.doi.org/10.1039/b713734fDOI Listing
January 2008

Phosphorus(V) porphyrins with axial carbazole-based dendritic substituents.

Org Lett 2007 Mar 1;9(5):797-800. Epub 2007 Feb 1.

Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, College of Chemistry, Jilin University, Changchun 130012, PRC.

[structure: see text] Three phosphorus(V) porphyrins with axial carbazole-based dendritic substituents (D-A-D) have been designed and synthesized, which are nonfluorescent due to their effective electron transfer from the carbazole dendron to the excited porphyrin within the dendritic matrix. The incident photon to current conversion efficiencies (IPCE) spectra demonstrate that the molecular structure of the dendrimers can significantly affect the photovoltaic response to the visible light.
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http://dx.doi.org/10.1021/ol062979kDOI Listing
March 2007
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