ORCID Profile
0000-0003-2132-8278
Current Organisations
Duke-NUS Graduate Medical School
,
Genome Institute of Singapore
,
National University of Singapore
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Publisher: Springer Science and Business Media LLC
Date: 17-10-2013
Publisher: Proceedings of the National Academy of Sciences
Date: 14-06-2016
Abstract: The plasticity of Polycomb repressive complex 2 (PRC2) in the context of tumorigenesis has remained a subject of contention. Here we demonstrate that the equilibrium between the oncogenic and tumor-suppressive activity of PRC2 in promoting breast cancer invasion is tightly regulated by hypoxia-inducible factor 1-α. PRC2 acts as a tumor-suppressor barrier to the hypoxia-driven invasion pathway, and the impaired PRC2 activity upon hypoxia promotes a chromatin switch at proinvasion matrix metalloproteinase gene loci. The study fundamentally changed our understanding of the role of PRC2 in breast cancer and also identified a previously unidentified function of enhancer of zeste 2 to complex with Forkhead box M1 to promote cancer invasion.
Publisher: Informa UK Limited
Date: 15-08-2016
Publisher: American Society of Hematology
Date: 08-09-2011
DOI: 10.1182/BLOOD-2010-07-294827
Abstract: Recent studies have shown that 3-Deazaneplanocin A (DZNep), a histone methyltransferase inhibitor, disrupts polycomb-repressive complex 2 (PRC2), and preferentially induces apoptosis in cancer cells, including acute myeloid leukemia (AML). However, the underlying molecular mechanisms are not well understood. The present study demonstrates that DZNep induces robust apoptosis in AML cell lines, primary cells, and targets CD34+CD38− leukemia stem cell (LSC)–enriched subpopulations. Using RNA interference (RNAi), gene expression profiling, and ChIP, we identified that TXNIP, a major redox control molecule, plays a crucial role in DZNep-induced apoptosis. We show that disruption of PRC2, either by DZNep treatment or EZH2 knockdown, reactivates TXNIP, inhibits thioredoxin activity, and increases reactive oxygen species (ROS), leading to apoptosis. Furthermore, we show that TXNIP is down-regulated in AML and is a direct target of PRC2-mediated gene silencing. Consistent with the ROS accumulation on DZNep treatment, we also see a signature of endoplasmic reticulum (ER) stress-regulated genes, commonly associated with cell survival, down-regulated by DZNep. Taken together, we uncover a novel molecular mechanism of DZNep-mediated apoptosis and propose that EZH2 may be a potential new target for epigenetic treatment in AML.
Publisher: Wiley
Date: 15-10-2014
Abstract: 3-Deazaneplanocin A (DzNep) is a potential epigenetic drug for the treatment of various cancers. DzNep has been reported to deplete histone methylations, including oncogenic EZH2 complex, giving rise to epigenetic modifications that reactivate many silenced tumor suppressors in cancer cells. Despite its promise as an anticancer drug, little is known about the structure-activity relationships of DzNep in the context of epigenetic modifications and apoptosis induction. In this study, a number of analogues of DzNep were examined for DzNep-like ability to induce synergistic apoptosis in cancer cells in combination with trichostatin A, a known histone deacetylase (HDAC) inhibitor. The structure-activity relationship data thus obtained provide valuable information on the structural requirements for biological activity. The studies identified three compounds that show similar activities to DzNep. Two of these compounds show good pharmacokinetics and safety profiles. Attempts to correlate the observed synergistic apoptotic activities with measured S-adenosylhomocysteine hydrolase (SAHH) inhibitory activities suggest that the apoptotic activity of DzNep might not be directly due to its inhibition of SAHH.
Publisher: Springer Science and Business Media LLC
Date: 05-2019
DOI: 10.1038/S41591-019-0423-5
Abstract: Understanding cellular metabolism holds immense potential for developing new classes of therapeutics that target metabolic pathways in cancer. Metabolic pathways are altered in bulk neoplastic cells in comparison to normal tissues. However, carcinoma cells within tumors are heterogeneous, and tumor-initiating cells (TICs) are important therapeutic targets that have remained metabolically uncharacterized. To understand their metabolic alterations, we performed metabolomics and metabolite tracing analyses, which revealed that TICs have highly elevated methionine cycle activity and transmethylation rates that are driven by MAT2A. High methionine cycle activity causes methionine consumption to far outstrip its regeneration, leading to addiction to exogenous methionine. Pharmacological inhibition of the methionine cycle, even transiently, is sufficient to cripple the tumor-initiating capability of these cells. Methionine cycle flux specifically influences the epigenetic state of cancer cells and drives tumor initiation. Methionine cycle enzymes are also enriched in other tumor types, and MAT2A expression impinges upon the sensitivity of certain cancer cells to therapeutic inhibition.
Publisher: Springer Science and Business Media LLC
Date: 27-10-2015
DOI: 10.1038/NCOMMS9746
Abstract: Metastatic tumour recurrence due to failed treatments remains a major challenge of breast cancer clinical management. Here we report that interleukin-1 receptor-associated kinase 1 (IRAK1) is overexpressed in a subset of breast cancers, in particular triple-negative breast cancer (TNBC), where it acts to drive aggressive growth, metastasis and acquired resistance to paclitaxel treatment. We show that IRAK1 overexpression confers TNBC growth advantage through NF-κB-related cytokine secretion and metastatic TNBC cells exhibit gain of IRAK1 dependency, resulting in high susceptibility to genetic and pharmacologic inhibition of IRAK1. Importantly, paclitaxel treatment induces strong IRAK1 phosphorylation, an increase in inflammatory cytokine expression, enrichment of cancer stem cells and acquired resistance to paclitaxel treatment. Pharmacologic inhibition of IRAK1 is able to reverse paclitaxel resistance by triggering massive apoptosis at least in part through inhibiting p38-MCL1 pro-survival pathway. Our study thus demonstrates IRAK1 as a promising therapeutic target for TNBC metastasis and paclitaxel resistance.
Publisher: Public Library of Science (PLoS)
Date: 30-04-2015
Publisher: Springer Science and Business Media LLC
Date: 10-07-2014
DOI: 10.1038/NCOMMS5361
Abstract: Chromatin alterations are fundamental hallmarks of cancer. To study chromatin alterations in primary gastric adenocarcinomas, we perform nanoscale chromatin immunoprecipitation sequencing of multiple histone modifications in five gastric cancers and matched normal tissues. We identify hundreds of somatically altered promoters and predicted enhancers. Many cancer-associated promoters localize to genomic sites lacking previously annotated transcription start sites (cryptic promoters), driving expression of nearby genes involved in gastrointestinal cancer, embryonic development and tissue specification. Cancer-associated promoters overlap with embryonic stem cell regions targeted by polycomb repressive complex 2, exhibiting promoter bivalency and DNA methylation loss. We identify somatically acquired elements exhibiting germline allelic biases and non-coding somatic mutations creating new promoters. Our findings demonstrate the feasibility of profiling chromatin from solid tumours with limited tissue to identify regulatory elements, transcriptional patterns and regulatory genetic variants associated with cancer.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2015
DOI: 10.1038/NCOMMS10054
Abstract: Nature Communications 6: Article number: 8746 (2015) Published: 27 October 2015 Updated: 20 November 2015 The original version of this Article contained an error in the spelling of the author Yi Bao, which was incorrectly given as Bao Yi. This has now been corrected in both the PDF and HTML versions of the Article.
Publisher: American Society for Clinical Investigation
Date: 15-11-2022
DOI: 10.1172/JCI159628
Publisher: Bentham Science Publishers Ltd.
Date: 2006
DOI: 10.2174/138920006774832550
Abstract: Topotecan (TPT) is a semisynthetic water-soluble derivative of c tothecin (CPT) used as second-line therapy in patients with metastatic ovarian carcinoma, small cell lung cancer, and other malignancies. However, both dose-limiting toxicity and tumor resistance hinder the clinical use of TPT. The mechanisms for resistance to TPT are not fully defined, but increased efflux of the drug by multiple drug transporters including P-glycoprotein (PgP), multidrug resistance associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) from tumor cells has been highly implicated. This study aimed to investigate whether overexpression of human MRP4 rendered resistance to TPT by examining the cytotoxicity profiles using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide (MTT) assay and cellular accumulation of TPT in HepG2 cells stably overexpressing MRP4. Two kinds of cell lines, HepG2 with insertion of an empty vector plasmid (V/HepG2), HepG2 cells stably expressing MRP4 (MRP4/HepG2), were exposed to TPT for 4 or 48 hr in the absence or presence of various MRP4 inhibitors including DL-buthionine-(S,R)-sulphoximine (BSO), diclofenac, celecoxib, or MK-571. The intracellular accumulation of TPT and paclitaxel (a PgP substrate) by V/HepG2 and MRP4/HepG2 cells was determined by incubation of TPT with the cells and the amounts of the drug in cells were determined by validated HPLC methods. The study demonstrated that MRP4 conferred a 12.03- and 6.86-fold resistance to TPT in the 4- and 48-hr drug-exposure MTT assay, respectively. BSO, MK-571, celecoxib, or diclofenac sensitised MRP4/HepG2 cells to TPT cytotoxicity and partially reversed MRP4-mediated resistance to TPT. In addition, the accumulation of TPT was significantly reduced in MRP4/HepG2 cells compared to V/HepG2 cells, and one-binding site model was found the best fit for the MRP4-mediated efflux of TPT, with an estimated K(m) of 1.66 microM and V(max) of 0.341 ng/min/106 cells. Preincubation of MRP4/HepG2 cells with BSO (200 microM) for 24 hr, celecoxib (50 microM), or MK-571 (100 microM) for 2 hr significantly increased the accumulation of TPT over 10 min in MRP4/HepG2 cells by 28.0%, 37.3% and 32.5% (P < 0.05), respectively. By contrast, there was no significant difference in intracellular accumulation of paclitaxel in V/HepG2 and MRP4/HepG2 cells over 120 min. MRP4 also rendered resistance to adefovir dipivoxil (bis-POM-PMEA) and methotrexate, two reported MRP4 substrates. MRP4 did not exhibit any significant resistance to other model drugs including vinblastine, vincristine, etoposide, carboplatin, cyclosporine and paclitaxel in both long (48 hr) and short (4 hr) drug-exposure MTT assays. These findings indicate that MRP4 confers resistance to TPT and TPT is the substrate for MRP4. Further studies are needed to explore the role of MRP4 in resistance to, toxicity and pharmacokinetics of TPT in cancer patients.
Publisher: American Society for Clinical Investigation
Date: 15-10-2021
DOI: 10.1172/JCI145035
Location: China
Location: China
No related grants have been discovered for Qiang Yu.