ORCID Profile
0000-0002-2894-1430
Current Organisations
University of Tokyo
,
University of Sydney
,
Children's Hospital at Westmead
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Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.JPEDS.2009.06.039
Abstract: We report a case of hepatoblastoma that developed in a child with Sotos syndrome, an overgrowth syndrome with an increased risk of neoplasms. Genome-wide analysis of copy number alterations showed a gain of chromosome 2, uniparental disomy of 18q, and microdeletion of 5q35.
Publisher: Wiley
Date: 03-07-2011
DOI: 10.1111/J.1349-7006.2011.01995.X
Abstract: MYEOV and NEGR1 are novel candidate gene targets in neuroblastoma that were identified by chromosomal gain in 11q13 and loss in 1p31, respectively, through single nucleotide polymorphism array analysis. In the present study, to assess the involvement of MYEOV and NEGR1 in the pathogenesis of neuroblastoma, we analyzed their mutation status and/or expression profiles in a panel of 55 neuroblastoma s les, including 25 cell lines, followed by additional functional studies. No tumor-specific mutations of MYEOV or NEGR1 were identified in our case series. Expression of MYEOV was upregulated in 11 of 25 cell lines (44%) and in seven of 20 fresh tumors (35%). The siRNA-mediated knockdown of MYEOV in NB-19 cells, which exhibit high expression of MYEOV, resulted in a significant decrease in cell proliferation (P = 0.0027). Conversely, expression studies of NEGR1 revealed significantly lower expression of this gene in neuroblastomas at an advanced stage of the disease. Exogenous NEGR1 expression in neuroblastoma cells induced significant inhibition of cell growth (P = 0.019). The results of these studies provide supporting evidence for MYEOV and NEGR1 as gene targets of 11q13 gains and 1p31 deletions in a neuroblastoma subset. In addition, the findings suggest a possible prognostic value for NEGR1 in neuroblastoma.
Publisher: Springer Science and Business Media LLC
Date: 10-2008
DOI: 10.1038/NATURE07399
Abstract: Neuroblastoma in advanced stages is one of the most intractable paediatric cancers, even with recent therapeutic advances. Neuroblastoma harbours a variety of genetic changes, including a high frequency of MYCN lification, loss of heterozygosity at 1p36 and 11q, and gain of genetic material from 17q, all of which have been implicated in the pathogenesis of neuroblastoma. However, the scarcity of reliable molecular targets has h ered the development of effective therapeutic agents targeting neuroblastoma. Here we show that the anaplastic lymphoma kinase (ALK), originally identified as a fusion kinase in a subtype of non-Hodgkin's lymphoma (NPM-ALK) and more recently in adenocarcinoma of lung (EML4-ALK), is also a frequent target of genetic alteration in advanced neuroblastoma. According to our genome-wide scans of genetic lesions in 215 primary neuroblastoma s les using high-density single-nucleotide polymorphism genotyping microarrays, the ALK locus, centromeric to the MYCN locus, was identified as a recurrent target of copy number gain and gene lification. Furthermore, DNA sequencing of ALK revealed eight novel missense mutations in 13 out of 215 (6.1%) fresh tumours and 8 out of 24 (33%) neuroblastoma-derived cell lines. All but one mutation in the primary s les (12 out of 13) were found in stages 3-4 of the disease and were harboured in the kinase domain. The mutated kinases were autophosphorylated and displayed increased kinase activity compared with the wild-type kinase. They were able to transform NIH3T3 fibroblasts as shown by their colony formation ability in soft agar and their capacity to form tumours in nude mice. Furthermore, we demonstrate that downregulation of ALK through RNA interference suppresses proliferation of neuroblastoma cells harbouring mutated ALK. We anticipate that our findings will provide new insights into the pathogenesis of advanced neuroblastoma and that ALK-specific kinase inhibitors might improve its clinical outcome.
Publisher: Informa UK Limited
Date: 15-09-2013
DOI: 10.4161/CC.26146
Publisher: Springer Science and Business Media LLC
Date: 03-2006
DOI: 10.1007/S11103-005-5082-X
Abstract: The Arabidopsis (Arabidopsis thaliana) genome contains 15 genes encoding protein homologs of the barley mildew resistance locus o (MLO) protein biochemically shown to have a seven-transmembrane domain topology and localize to the plasma membrane. Towards elucidating the functions of MLOs, the largest family of seven-transmembrane domain proteins specific to plants, we comprehensively determined AtMLO gene expression patterns by a combination of experimental and in silico studies. Experimentation comprised analyses of transgenic Arabidopsis lines bearing promoter::Beta-glucuronidase (GUS) transcriptional fusions as well as semi-quantitative determination of transcripts by reverse transcription coupled to polymerase chain reaction (RT-PCR). These results were combined with information extracted from public gene profiling databases, and compared to the expression patterns of genes encoding the heterotrimeric G-protein subunits. We found that each AtMLO gene has a unique expression pattern and is regulated differently by a variety of biotic and/or abiotic stimuli, suggesting that AtMLO proteins function in erse developmental and response processes. The expression of several phylogenetically closely-related AtMLO genes showed similar or overlapping tissue specificity and analogous responsiveness to external stimuli, suggesting functional redundancy, co-function, or antagonistic function(s).
Publisher: Springer Science and Business Media LLC
Date: 19-07-2001
Abstract: We previously reported a high incidence of loss of heterozygosity (LOH) on chromosome 2q33 in neuroblastoma (NB), observed in various types of human cancers including lung cancer, head and neck cancer and follicular thyroid carcinoma. To better elucidate the role of chromosome 2q aberrations in NB, we examined common allelic imbalance (AI) regions on chromosome 2q in 82 NB patients using 10 polymorphic microsatellite markers. AI on 2q was detected in 26 (32%) of 82 NB cases. There was a distinct common AI region between the D2S115 and D2S307 markers on 2q33. The distance between these markers was about 2.0 cM. Recently, the caspase 8 and caspase 10 genes, both of which encode cystein protease, were mapped to chromosome 2q33. Since the common AI region on 2q33 includes the caspase 8 and caspase 10 genes, the alterations of these genes were examined further. Absent or reduced expression of caspase 8 and caspase 10 were found in 19 (70%) of 27 and two (7%) of 27 NB cell lines by reverse transcription-polymerase chain reaction, respectively. A missense mutation was detected at codon 96, GCT (Alanine) to GTT (Valine), of the caspase 8 gene in one of the NB cell lines lacking caspase 8 expression. Thirteen (68%) of 19 cell lines lacking caspase 8 expression displayed methylation of the CpG island of the caspase 8 gene, whereas only one (13%) of eight cell lines with caspase 8 expression showed caspase 8 methylation (P=0.031). Furthermore, there was a significant association between AI at 2q33 and loss of caspase 8 expression (P=0.026). These results indicated that there was a tumor suppressor gene in the common AI region on chromosome 2q33 involved in the pathogenesis of a subset of NB. It is possible that the caspase 8 gene is one of the candidate tumor suppressor genes for NB and inactivation of this gene plays an important role in the tumorigenesis of NB through mainly its methylation.
Publisher: Wiley
Date: 26-02-2014
DOI: 10.1111/CAS.12352
Publisher: Wiley
Date: 22-01-2007
DOI: 10.1002/GCC.20416
Abstract: Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of childhood. The simultaneous loss of Ink4a/Arf function and disruption of Met signaling in Ink4a/Arf-/- mice transgenic for hepatocyte growth factor/scatter factor (HGF/SF) induces RMS with extremely high penetrance and short latency. To address the roles of MET and CDKN2A (p16INK4A 14ARF) in human RMS, we performed mutational analyses in 39 s les of RMS by PCR-SSCP. No mutations were detected in exons 14-21 of MET whereas a nonsense mutation at codon 80 of p16(INK4A) was identified in an alveolar RMS cell line. We also quantified the relative expression levels and DNA copy numbers of these genes in seven cell lines and 17 fresh tumors by real-time quantitative PCR. Expression of MET was detected in all s les however, more than 10-fold difference was found in the s les with higher or lower expression level, despite a normal DNA copy number. The protein expression level was consistent with that of mRNA, and in cell lines with a higher expression level, MET was constitutively activated. Notably, the expression level of MET was significantly higher in patients who died (P = 0.02), in patients with stage IV (P = 0.04), as well as in patients with PAX3-FKHR chimeric transcript (P = 0.04). On the other hand, reduced or absent expression of p16INK4A and/or p14(ARF) showed no significant correlation with the clinicopathological parameters, except for the age at diagnosis. Our data suggest that MET plays a role in the progression of RMS.
Publisher: Wiley
Date: 09-05-2013
DOI: 10.1002/MC.22038
Abstract: TPD52 and ERBB2 co-expression has been persistently reported in human breast cancer and animal models of this disease, but the significance of this is unknown. We identified significant positive associations between relative TPD52 and ERBB2 transcript levels in human diagnostic breast cancer s les, and maximal TPD52 expression in the hormone receptor (HR)- and ERBB2-positive sub-group. High-level TPD52 expression was associated with significantly reduced metastasis-free survival, within the overall cohort (log rank test, P = 8.6 × 10(-4), n = 375) where this was an independent predictor of metastasis-free survival (hazard ratio, 2.69, 95% confidence interval 1.59-4.54, P = 2.2 × 10(-4), n = 359), and the HR- and ERBB2-positive sub-group (log rank test, P = 0.035, n = 47). Transient TPD52 knock-down in the ERBB2- lified breast cancer cell lines SK-BR-3 and BT-474 produced significant apoptosis, both singly and in combination with transient ERBB2 knock-down. Unlike ERBB2 knock-down, transient TPD52 knock-down produced no reduction in pAKT levels in SK-BR-3 or BT-474 cells. We then derived multiple SK-BR-3 cell lines in which TPD52 levels were stably reduced, and measured significant inverse correlations between pERBB2 and TPD52 levels in viable TPD52-depleted and control cell lines, all of which showed similar proliferative capacities. Our results therefore identify TPD52 as a survival factor in ERBB2- lified breast cancer cells, and suggest complementary cellular functions for TPD52 and ERBB2.
Publisher: BMJ
Date: 04-10-2018
DOI: 10.1136/JMEDGENET-2018-105488
Abstract: Genetic predisposition is an important underlying cause of childhood cancer, although the proportion of patients with childhood cancer carrying predisposing pathogenic germline variants is uncertain. This review considers the pathogenic or likely pathogenic germline variants reported by six studies that used next-generation sequencing to investigate genetic predisposition in selected cohorts of patients with childhood cancer and used incompletely overlapping gene sets for analysis and interpretation. These six studies reported that 8.5%–35.5% of patients with childhood cancer carried clinically relevant germline variants. Analysis of 52 autosomal dominant cancer predisposition genes assumed common to all six studies showed that 5.5%–25.8% of patients with childhood cancer carried pathogenic or likely pathogenic germline variants in at least one of these genes. When only non-central nervous system solid tumours (excluding adrenocortical carcinomas) were considered, 8.5%–10.3% of the patients carried pathogenic or likely pathogenic germline variants in at least one of 52 autosomal dominant cancer predisposition genes. There was a lack of concordance between the genotype and phenotype in 33.3%–57.1% of the patients reported with pathogenic or likely pathogenic germline variants, most of which represented variants in autosomal dominant cancer predisposition genes associated with adult onset cancers. In summary, germline genetic testing in patients with childhood cancer requires clear definition of phenotypes and genes considered for interpretation, with potential to inform and broaden childhood cancer predisposition syndromes.
Publisher: Springer Science and Business Media LLC
Date: 03-05-2009
DOI: 10.1038/NATURE07969
Abstract: A20 is a negative regulator of the NF-kappaB pathway and was initially identified as being rapidly induced after tumour-necrosis factor-alpha stimulation. It has a pivotal role in regulation of the immune response and prevents excessive activation of NF-kappaB in response to a variety of external stimuli recent genetic studies have disclosed putative associations of polymorphic A20 (also called TNFAIP3) alleles with autoimmune disease risk. However, the involvement of A20 in the development of human cancers is unknown. Here we show, using a genome-wide analysis of genetic lesions in 238 B-cell lymphomas, that A20 is a common genetic target in B-lineage lymphomas. A20 is frequently inactivated by somatic mutations and/or deletions in mucosa-associated tissue lymphoma (18 out of 87 21.8%) and Hodgkin's lymphoma of nodular sclerosis histology (5 out of 15 33.3%), and, to a lesser extent, in other B-lineage lymphomas. When re-expressed in a lymphoma-derived cell line with no functional A20 alleles, wild-type A20, but not mutant A20, resulted in suppression of cell growth and induction of apoptosis, accompanied by downregulation of NF-kappaB activation. The A20-deficient cells stably generated tumours in immunodeficient mice, whereas the tumorigenicity was effectively suppressed by re-expression of A20. In A20-deficient cells, suppression of both cell growth and NF-kappaB activity due to re-expression of A20 depended, at least partly, on cell-surface-receptor signalling, including the tumour-necrosis factor receptor. Considering the physiological function of A20 in the negative modulation of NF-kappaB activation induced by multiple upstream stimuli, our findings indicate that uncontrolled signalling of NF-kappaB caused by loss of A20 function is involved in the pathogenesis of subsets of B-lineage lymphomas.
Publisher: Springer Science and Business Media LLC
Date: 05-07-2019
DOI: 10.1038/S41598-019-46156-1
Abstract: Tumor protein D52 (TPD52) is lified and overexpressed in breast and prostate cancers which are frequently characterised by dysregulated lipid storage and metabolism. TPD52 expression increases lipid storage in mouse 3T3 fibroblasts, and co-distributes with the Golgi marker GM130 and lipid droplets (LDs). We examined the effects of Brefeldin A (BFA), a fungal metabolite known to disrupt the Golgi structure, in TPD52-expressing 3T3 cells, and in human AU565 and HMC-1-8 breast cancer cells that endogenously express TPD52. Five-hour BFA treatment reduced median LD numbers, but increased LD sizes. TPD52 knockdown decreased both LD sizes and numbers, and blunted BFA’s effects on LD numbers. Following BFA treatment for 1–3 hours, TPD52 co-localised with the trans-Golgi network protein syntaxin 6, but after 5 hours BFA treatment, TPD52 showed increased co-localisation with LDs, which was disrupted by microtubule depolymerising agent nocodazole. BFA treatment also increased perilipin (PLIN) family protein PLIN3 but reduced PLIN2 detection at LDs in TPD52-expressing 3T3 cells, with PLIN3 recruitment to LDs preceding that of TPD52. An N-terminally deleted HA-TPD52 mutant (residues 40–184) almost exclusively targeted to LDs in both vehicle and BFA treated cells. In summary, delayed recruitment of TPD52 to LDs suggests that TPD52 participates in a temporal hierarchy of LD-associated proteins that responds to altered LD packaging requirements induced by BFA treatment.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2007
Publisher: SAGE Publications
Date: 02-2012
No related grants have been discovered for Yuyan Chen.