Biomedical subjects

Long Cheng

Publications and source records attributed to Long Cheng.

16 recordsLinked to original sources

PubMed2026

CancerOmicsStudio (CoS): a web server for integrative and interpretable analysis of multi-omics cancer data.

MOTIVATION: Large-scale omics resources, including The Cancer Genome Atlas, Genomics of Drug Sensitivity in Cancer, and the Cancer Dependency Map, have become essential for cancer research. However, these datasets are distributed across different platforms, formats and analysis frameworks, which limits their practical use by researchers without extensive computational expertise. RESULTS: We developed CancerOmicsStudio (CoS), a web server for integrative and interpretable analysis of multi-omics cancer data across 33 cancer types. CoS provides five major modules: CosAI, Traditional Analysis, Drug Sensitivity, CRISPR Dependency and Single-Cell Tumor Microenvironment. The Traditional Analysis module supports expression comparison, diagnostic evaluation, survival analysis, enrichment analysis and gene correlation. The Drug Sensitivity and CRISPR Dependency modules enable systematic evaluation of gene-drug response associations and gene essentiality in cancer cell lines. The Single-Cell Tumor Microenvironment module supports tumor microenvironment analysis at single-cell resolution. In total, approximately 1.23 million results have been precomputed to enable rapid retrieval. CosAI further allows users to submit natural-language queries and obtain results through a Real-time Analysis as Retrieval framework, with responses summarized by a lightweight language model. AVAILABILITY AND IMPLEMENTATION: CancerOmicsStudio is freely available at Zenodo (doi: 10.5281/zenodo.18744990) and https://cos.wanglab.bio.

Humans↗

PubMed2006

Catalytic properties of MGAT3, a putative triacylgycerol synthase.

Acyl-coenzyme A:monoacylglycerol acyltransferase 3 (MGAT3) is a member of the MGAT family of enzymes that catalyze the synthesis of diacylglycerol (DAG) from monoacylglycerol (MAG), a committed step in dietary fat absorption. Although named after the initial identification of its MGAT activity, MGAT3 shares higher sequence homology with acyl-coenzyme A:diacylglycerol acyltransferase 2 (DGAT2) than with other MGAT enzymes, suggesting that MGAT3 may also possess significant DGAT activity. This study compared the catalytic properties of MGAT3 with those of MGAT1 and MGAT2 enzymes using both MAG and DAG as substrates. Our results showed that in addition to the expected MGAT activity, the recombinant MGAT3 enzyme expressed in Sf-9 insect cells displayed a strong DGAT activity relative to that of MGAT1 and MGAT2 enzymes in the order MGAT3 > MGAT1 > MGAT2. In contrast, none of the three MGAT enzymes recognized biotinylated acyl-CoA or MAG as a substrate. Although MGAT3 possesses full DGAT activity, it differs from DGAT1 in catalytic properties and subcellular localization. The MGAT3 activity was sensitive to inhibition by the presence of 1% CHAPS, whereas DGAT1 activity was stimulated by the detergent. Consistent with high sequence homology with DGAT2, the MGAT3 enzyme demonstrated a similar subcellular distribution pattern to that of DGAT2, but not DGAT1, when expressed in COS-7 cells. Our data suggest that MGAT3 functions as a novel triacylglycerol (TAG) synthase that catalyzes efficiently the two consecutive acylation steps in TAG synthesis.

Acyltransferases↗

PubMed2006

Characterization of self-assembled monolayers of fullerene derivatives on gold surfaces: implications for device evaluations.

The widely employed approach to self-assembly of fullerene derivatives on gold can be complicated due to multilayer formations and head-to-tail assemblies resulting from the strong fullerene-fullerene and fullerene-gold interactions. These anomalies were not examined in detail in previous studies on fullerene self-assembled monolayers (SAMs) but were clearly detected in the present work using surface characterization techniques including ellipsometry, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). This is the first time that SAMs prepared from fullerene derivatives of thiols/thiol esters/disulfides have been analyzed in detail, and the complications due to multilayer formations and head-to-tail assemblies were revealed. Specifically, we designed and synthesized several fullerene derivatives based on thiols, thiol acetates, and disulfides to address the characterization requirements, and these are described and delineated. These studies specifically address the need to properly characterize and control fullerene-thiol assemblies on gold before evaluating subsequent device performances.

Journal Article↗

PubMed2006

Wilms' tumor 1 and signal transducers and activators of transcription 3 synergistically promote cell proliferation: a possible mechanism in sporadic Wilms' tumor.

Transcription factor Wilms' tumor 1 (WT1) was originally identified as a tumor suppressor for Wilms' tumor, but it is also overexpressed in a variety of cancer cells, suggesting a potential oncogenic function of WT1. It is important to understand molecular mechanisms underlying these dual functions of WT1 in tumorigenesis. In the current study, we report a synergistic role for signal transducers and activators of transcription 3 (STAT3) and WT1 in tumor development, including Wilms' tumor. STAT3 interacts with WT1 through its conserved domains both in vitro and in vivo. When STAT3 is activated, expression of WT1 enhances STAT3 transcriptional activity. Overexpression of WT1 and STAT3CA in NIH 3T3 increases the expression level of STAT3 target genes, including cyclin D1 and Bcl-xL, which results in an advantage of cell proliferation. Our results suggest that in the presence of activated STAT3, WT1 promotes cell proliferation instead of suppressing cell proliferation. Strikingly, STAT3 translocates to the nucleus and interacts with WT1 in a variety of primary Wilms' tumor cells, raising the hypothesis that WT1 and activated STAT3 in Wilms' tumor accelerate tumorigenesis.

Activating Transcription Factor 3↗

PubMed2006

hSef co-localizes and interacts with Ras in the inhibition of Ras/MAPK signaling pathway.

To study the mechanism of the inhibitory effects of Sef (similar expression to fgf genes) on Ras/mitogen-activated protein kinase (MAPK) signaling pathway, we observed cellular localization of this protein. Immunofluorescent staining results show that Sef locates in the vesicles of the cytoplasm without bFGF treatment but co-localizes with Ras on the plasma membrane (PM) in response to bFGF stimulation. The coimmunoprecipitation assay demonstrates that Sef interacts with Ras or RasG12V, respectively. We observed that Sef inhibited FGF induced, but not RasG12V mediated, signal transduction. We propose that Sef interacted with Ras in the inhibition of Ras/MAPK signaling pathway.

Animals↗

PubMed2006

Sef-S, an alternative splice isoform of sef gene, inhibits NIH3T3 cell proliferation via a mitogen-activated protein kinases p42 and p44 (ERK1/2)-independent mechanism.

sef (similar expression to fgf genes) was recently identified as a negative regulator of fibroblast growth factor (FGF) signaling in zebrafish, chicken, mouse and human. By repressing events upstream and/or downstream Ras, Sef inhibits FGF-induced ERK activation and cell proliferation. Here we report that Sef-S, an alternative splice isoform of Sef, lacks a signal peptide and is localized in cytosol. Sef-S inhibits FGF-induced NIH3T3 cell proliferation, a similar function to Sef. However, Sef-S represses neither the intensity nor the duration of ERK activation. Moreover, Sef-S does not inhibit Elk1-dependent transcription. Our study revealed that the signal peptide is critical for the different activities between Sef and Sef-S in FGF-Ras-MAPK signaling cascades. Furthermore, we observed that Sef-S associated with FGFR2 in a co-immunoprecipitated complex. These results indicate that Sef-S inhibits FGF-induced NIH3T3 cell proliferation via an ERK-independent mechanism and therefore suggest that alternative splice licenses sef gene to inhibit cell proliferation via multiple signaling pathways.

Alternative Splicing↗

PubMed2006

Neutral complexes of first row transition metals bearing unbound thiocyanates and their assembly on metallic surfaces.

A series of transition metal coordination complexes designed to assemble on gold surfaces was synthesized, their electronic structure and transitions analyzed, and their magnetic properties studied. By taking advantage of recently developed thiocyanate assembly protocols, these molecules were then assembled onto a gold surface, without the need for an inert atmosphere, to give a loosely packed monolayer. The assembled molecules exhibit properties similar to that of the bulk molecules, indicating little change in molecular structure outside of chemisorption.

Journal Article↗

PubMed2006

[Research of kingsbrain on improving the learning and memory ability of MCAO rats].

OBJECTIVE: To explore the influence of Kingsbrain (GETO) on the learning memory impairment of rats with cerebral ischemia. METHOD: Rats with cerebral ischemia were administered GETO orally once a day for one month. The ability of spatial-learning memory of rats was evaluated by Morris Water Maze (MWM). Duxil was used as a positive control. RESULT: the results of place navigation of MWM showed that at the 3rd time of swimming training, the escape latency of rats of the GETO group, Duxil group and Sham group were shorter than that of model group. The escape latency were (54.1 +/- 43.94), (55.9 +/- 43.49), (50.4 +/- 34.99) and (85.4 +/- 42.8) s, respectively; but there was no significantly difference. After the 6th time of swimming training, the escape latency of rats of the GETO group (37.8 +/- 38.69) s, the Duxil group (37.4 +/- 38.03) s and the sham group (26.9 +/- 21.63) s were significantly shorter than that of model rats (77.5 +/- 47.59) s, P < 0.05, respectively. Comparison of the swimming distance among groups were similar to the escape latency among groups. In the test of spatial probe, results of the ratio of the swimming time of platform quadrant (tP) vs the total swimming time (tT) and the ratio of the swimming distance of platform quadrant (dP) vs the total swimming distance (dT) indicated that the ratios of the GETO group (0.347 +/- 0.0662, 0.344 +/-0.055 1), the Duxil group (0.345 +/- 0.0984, 0.34 +/- 0.0934) and the sham group (0.35 +/- 0.0662, 0.349 +/- 0.0589) were significantly higher than those of the Model group (0.261 +/- 0.0689, 0.274 +/- 0.0544), P < 0.05, respectively. CONCLUSION: GETO can significantly improve the spatial learning and memory ability of rats with cerebral ischemia, which provides the pharmacodynamics evidence for its clinical application of improveing the learning and memory ability in poststroke patients.

Animals↗

PubMed2005

Synthesis, spectroscopic and nonlinear optical properties of multiple [60]fullerene-oligo(p-phenylene ethynylene) hybrids.

A series of multiple [60]fullerene terminated oligo(p-phenylene ethynylene) (OPE) hybrid compounds has been synthesized through a newly developed in situ ethynylation method. Structural and magnetic shielding properties of the highly unsaturated carbon-rich C(60) and OPE scaffolds were characterized by 1D and 2D NMR spectroscopic analyses. Electronic interactions between the [60]fullerenes and the OPE backbones were investigated by UV/Vis spectroscopic and cyclic voltammetry (CV) experiments. Our studies clearly show that although the multiple [60]fullerene groups are connected via pi-conjugated OPE frameworks, they present diminutive electronic interactions in the ground state, and the electronic behavior of the [60]fullerene cages are only affected by the OPE backbones through modest inductive effects. Interestingly, sizable third-order nonlinear optical (NLO) responses (gamma) and enhanced two-photon absorption (TPA) cross-sections (sigma((2))) were determined for the multifullerene-OPE hybrid 31 relative to its OPE precursor from differential optical Kerr effect (DOKE) experiments. Such enhanced NLO performance is presumably due to the occurrence of periconjugation and/or charge transfer effects in the excited state. In addition, comparatively strong excited-state absorption was observed and characterized for OPE pentamer 12. Thus, the use of such fullerene-derivatized conjugated oligomers aids the quest for molecules with large third-order NLO and TPA properties.

Fullerenes↗

PubMed2004

Facile synthesis of multifullerene-OPE hybrids via in situ ethynylation.

[reaction: see text] A series of fullerene-terminated oligo(phenylene ethynylene)s (OPEs) (1a-d and 2) have been synthesized and further characterized by cyclic voltammetry (CV) and UV-vis spectroscopy. The key step in the syntheses is an effective one-pot reaction that allows the attachment of C(60) to multiple terminal alkynes.

Journal Article↗

PubMed2004

Structure-dependent charge transport and storage in self-assembled monolayers of compounds of interest in molecular electronics: effects of tip material, headgroup, and surface concentration.

The electrical properties of self-assembled monolayers (SAMs) on a gold surface have been explored to address the relation between the conductance of a molecule and its electronic structure. We probe interfacial electron transfer processes, particularly those involving electroactive groups, of SAMs of thiolates on Au by using shear force-based scanning probe microscopy (SPM) combined with current-voltage (i-V) and current-distance (i-d) measurements. Peak-shaped i-V curves were obtained for the nitro- and amino-based SAMs studied here. Peak-shaped cathodic i-V curves for nitro-based SAMs were observed at negative potentials in both forward and reverse scans and were used to define the threshold tip bias, V(TH), for electric conduction. For a SAM of 2',5'-dinitro-4,4'-bis(phenylethynyl)-1-benzenethiolate, VII, V(TH) was nearly independent of the tip material [Ir, Pt, Ir-Pt (20-80%), Pd, Ni, Au, Ag, In]. For all of the SAMs studied, the current decreased exponentially with increasing distance, d, between tip and substrate. The exponential attenuation factors (beta values) were lower for the nitro-based SAMs studied here, as compared with alkylthiol-based SAMs. Both V(TH) and beta of the nitro-based SAMs also depended strongly on the molecular headgroup on the end benzene ring addressed by the tip. Finally, we confirmed the "memory" effect observed for nitro-based SAMs. For mixed SAMs of VII and hexadecanethiol, I, the fraction of the charge collected in the negative tip bias region that can be read out at a positive tip bias on reverse scan (up to 38%) depended on the film composition and decreased with an increasing fraction of I, suggesting that lateral electron hopping among molecules of VII occurs in the vicinity of the tip.

Journal Article↗

PubMed2004

Electrons are transported through phenylene-ethynylene oligomer monolayers via localized molecular orbitals.

We report excellent correlations between the first negative threshold potentials (V(TH)s) for electric conduction, electrochemical potentials, and computed lowest unoccupied molecular orbital energies in a series of phenylene-ethynylene oligomers bearing a sulfur-based anchoring unit and different electroactive substituents on the central benzene ring. The theoretical and electrochemical results strongly suggest that the peaks observed in the i-V curves have a true molecular origin and are associated with distinct unoccupied molecular levels of the compounds that are strongly localized on the central ring (except for compound I). This localization might account for the existence of a long-lived radical-anion state that permits lateral electron hopping and leads to charge trapping and storage.

Journal Article↗

PubMed2004

Comparative study of electrochemically directed assembly versus conventional self-assembly of thioacetyl-terminated oligo(phenylene ethynylene)s on gold and platinum surfaces.

The assembly of thioacetyl-terminated oligo(phenylene ethynylene)s (OPEs) on Au and Pt surfaces under an electric potential (electrochemical assembly, EA) was compared to assembly at an open circuit (conventional self-assembly, CSA). Cyclic voltammetry and ellipsometry were used to characterize the adsorption kinetics of self-assembled monolayers formed by these two techniques. The adsorption rate of the EA was remarkably faster at positive potentials but slower at negative potentials than that of the CSA, The EA at 400 mV proceeded about 800 times faster than the CSA when exposed to the same solution concentrations. The adsorption rates of both EA and CSA were found to be dependent on the molecular structures of OPEs. OPEs containing electron-donating groups assemble faster than those with electron-withdrawing groups. The amount of time that the thioacetyl-terminated OPE is in the presence of the base, for removal of the acetyl group to generate the thiolate, is called the deprotection time. Deprotection times play a critical role in achieving the maximum difference in adsorption rates between the EA and the CSA. The assembly must be initiated no later than 5 min after the basic deprotection is commenced so that the thiolate concentration remains low. The difference in the adsorption rates between EA and CSA might enable selective deposition of certain OPEs onto specific electrodes.

Journal Article↗

PubMed2004

Clustering effects on discontinuous gold film NanoCells.

Reproducible negative differential resistance (NDR)-like switching behavior is observed in NanoCells. This behavior is attributed to the formation of filaments and clusters between the discontinuous gold films. Control experiments are performed by self-assembly of insulating molecules between the gold islands and conducting molecules on these islands. Additional control experiments are performed by removing the filaments and clusters between islands using a piranha bath. The results are consistent with theoretical predictions and extend the domain of molecular electronics based in organic molecules to include nanosized clusters as active units. This facilitates a scenario where synthetically accessible organic molecules, with defined characteristics, can be adjusted by metallic nanoclusters as an in situ fine-tuning element, able to compensate for the lack of addressing in the nanosize regime.

Electric Impedance↗

PubMed2003

NanoCell electronic memories.

NanoCells are disordered arrays of metallic islands that are interlinked with molecules between micrometer-sized metallic input/output leads. In the past, simulations had been conducted showing that the NanoCells may function as both memory and logic devices that are programmable postfabrication. Reported here is the first assembly of a NanoCell with disordered arrays of molecules and Au islands. The assembled NanoCells exhibit reproducible switching behavior and two types of memory effects at room temperature. The switch-type memory is characteristic of a destructive read, while the conductivity-type memory features a nondestructive read. Both types of memory effects are stable for more than a week at room temperature, and bit level ratios (0:1) of the conductivity-type memory have been observed to be as high as 10(4):1 and reaching 10(6):1 upon ozone treatment, which likely destroys extraneous leakage pathways. Both molecular electronic and nanofilamentary metal switching mechanisms have been considered, though the evidence points more strongly toward the latter. The approach here demonstrates the efficacy of a disordered nanoscale array for high-yielding switching and memory while mitigating the arduous task of nanoscale patterning.

Journal Article↗

PubMed2002

[Clinical observation on dusuqing in treating senile bacterial pneumonia].

OBJECTIVE: To evaluate the clinical effect of Dusuqing (DSQ) in treating senile bacterial pneumonia and to explore its possible mechanism. METHODS: Patients were randomly divided into two groups, the treated group treated with conventional western therapy (CWT) and the combined treated group treated with CWT plus DSQ respectively. The changes of serum cytokines, interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha), before and after treatment were observed. RESULTS: In the 33 patients of the combined treated group, the total effective rate being 93.9%. While in the 31 patients of treated group, the total effective rate being 83.9%. The difference of the total effective rate between the two groups was significant (P < 0.05). The scores of principal symptoms, secondary symptoms and total scores were all obviously lowered in both groups, particularly in the combined treated group. The peripheral blood IL-2 level was lower and TNF-alpha higher in senile patients than those in healthy aged subjects respectively. All the two parameters approached normal level in the combined treated group but with insignificant change in the CWT treated group. CONCLUSION: DSQ showed obvious effect in treating senile bacterial pneumonia. The mechanism might be related with the lowering of inflammatory cytokines such as oversecreted TNF-alpha, as well as the improvement of immune function (elevation of IL-2) of organism.

Aged↗