Tong-Tong Zhang

Chinese Academy of Medical Sciences, Peping, Beijing, China

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Publications (9)50.34 Total impact

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    ABSTRACT: Our aim was to identify frequent genomic aberrations in both ESCC and esophageal dysplasia and to discover important copy number-driving genes and microRNAs in ESCC. We conducted array-based comparative genomic hybridization (array CGH) on 59 ESCC resection samples and 16 dysplasia biopsy samples. Expression of genes at 11q13.3 was analyzed by real-time PCR and immunohistochemistry (IHC). Integrated analysis was performed to identify genes or microRNAs with copy number-expression correlations. Array CGH identified 11 amplifications and 8 homozygous deletions (HDs) in ESCC. Integrated analysis of array CGH data with matched gene expression microarray data showed that 90 overexpressed genes and 24 underexpressed genes were consistent with DNA copy number changes, including 12 copy number-driving microRNAs. In esophageal dysplasia, 6 gains, 4 losses, 12 amplifications and 4 homozygous deletions were detected. Amplifications of 7p11.2 and 11q13.2-11q13.3 (CCND1) and homozygous deletion at 9p21.3 (CDKN2A) were consistent genomic changes in both dysplasia and carcinoma. ANO1 at 11q13.3 was overexpressed at the mRNA and protein levels in tumors, and higher mRNA expression was correlated with the copy number increase. In particular, ANO1 expression was elevated in moderate dysplasia compared to normal esophageal epithelium. Immunohistochemistry revealed that ANO1 overexpression was positively correlated with lymph node metastasis and advanced clinical stage. Knock-down of ANO1 significantly inhibited the proliferation of KYSE30 and KYSE510 cells. Copy number aberrations in both esophageal dysplasia and ESCC may be useful as potential biomarkers for early detection. Additionally, ANO1 may be a candidate target gene in esophageal tumorigenesis.
    Clinical Cancer Research 09/2013; 19(21). DOI:10.1158/1078-0432.CCR-12-3753 · 8.19 Impact Factor
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    ABSTRACT: Calreticulin (CRT) is a Ca2+-binding protein that alters Ca2+-homeostasis in the endoplasmic reticulum (ER) by acting as a chaperone in cells. We previously showed that CRT was overexpressed in esophageal squamous cell carcinoma (ESCC), and elevated CRT expression promoted the migration and invasion of ESCC cells. In the present study, we investigate the mechanisms underlying role of CRT in esophageal carcinoma progression. We found that depletion of CRT or protein-tyrosine phosphatase 1B (PTP1B) reduced ESCC cell migration and metastasis to the lung, while restoration of PTP1B protein levels rescued cell migration in CRT-silenced cells. Knock-down of CRT decreased PTP1B protein expression by reducing phosphorylation at the Y694 site of Stat5a, while knock-down of PTP1B reduced Erk1/2 phosphorylation at T204. Immunohistochemical analysis of CRT and PTP1B expression in ESCC patient tissues revealed that their expressions were correlated. PTP1B expression was also associated with poor survival in patients with CRT overexpression. Overall, our data indicate a novel signaling pathway connecting CRT, Stat5a, PTP1B and Erk1/2 in the regulation of ESCC cell migration. These findings suggest that PTP1B is a downstream effector of CRT signaling that promotes ESCC progression and can potentially be used as a new drug target.
    Molecular Cancer Research 06/2013; DOI:10.1158/1541-7786.MCR-12-0704 · 4.50 Impact Factor
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    ABSTRACT: The aim of the present study was to screen and identify the chromosomal aberrations that are correlated with clinicopathological characteristics of rectal cancer using array-based comparative genomic hybridization (array-CGH). Forty-eight fresh frozen tumor tissues of rectal carcinoma were analyzed by array-CGH. The results showed that most frequent gains included 8q24.3, 20q11.21-q13.32, 20q13.33 and losses in 8p23.3-p12, 17p13.1-p12 and 18q11.2-q23 were noted. Fourteen amplifications and seven homozygous deletions were identified in the rectal cancer samples. Losses of 4p16.1-p15.31, 8p21.1-p12 and gains of 7p12.3-p12.1 and 13q33.1-q34 were associated with positive lymph node status and advanced clinical stage (stages III and IV). The 17q24.2-25.3 gain was more frequent in patients with distant metastasis. Integrated analysis indicated that overexpression of PDP1, TRIB1, C13orf27, FOXA2, PMEPA1 and PHACTR3 was associated with gains, and underexpression of FHOD, SMAD4 and BCL2 was associated with losses. Pathway enrichment analysis showed that pathways of nitrogen metabolism, oxidative phosphorylation, cell cycle, maturity onset diabetes of young, cytokine-cytokine receptor interaction, MAPK signaling pathway and dentatorubropallidoluysian atrophy were influenced by copy number changes.
    Oncology Reports 02/2013; 29(5). DOI:10.3892/or.2013.2296 · 2.19 Impact Factor
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    ABSTRACT: At present no objective parameters to identify the risk of liver metastasis after surgery have been established in rectal cancer. To identify the chromosomal aberrations that are correlated with liver metastasis of rectal cancer. Primary tumor tissues of rectal carcinoma were analyzed by array-based comparative genomic hybridization (array-CGH). Genomic aberrations were identified by Genomic Workbench and MD-SeeGH. The most frequent gains in rectal cancer were at 20q11.21-q13.33, 8q11.21-q24.3, 13q12.11-q14.2 and losses in 5q13.2, 8p23.3-p22, 17p13.3-p13.2 and 18q11.2-q23. Seven amplifications at 6p21.1, 8q24.21, 8q24.3, 13q13.2 and 20q13.2-q13.32 and nine homozygous deletions at 1q31.3, 4q12-q13.1, 4q32.3-q33, 5q13.2, 8p23.2, 8q11.23, 16p13.2, 19p13.11 and 19q13.41 were identified. Both frequency plot comparison and SAM (Significance analysis of microarray) methods indicated that losses at 1p35.3, 4p14, 14q23.1-q32.11 and 18p11.32-p11.21 were more frequent in patients without liver metastasis. These liver metastasis associated genomic changes may be useful to reveal the mechanism of metastasis and identify candidate biomarkers.
    Cancer biomarkers: section A of Disease markers 01/2013; 13(4):281-8. DOI:10.3233/CBM-130351 · 1.19 Impact Factor
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    ABSTRACT: Background Rectal cancer is one of the most common cancers in the world. Early detection and early therapy are important for the control of death caused by rectal cancer. The present study aims to investigate the genomic alterations in rectal adenoma and carcinoma. Methods We detected the genomic changes of 8 rectal adenomas and 8 carcinomas using array CGH. Then 14 genes were selected for analyzing the expression between rectal tumor and paracancerous normal tissues as well as from adenoma to carcinoma by real-time PCR. The expression of GPNMB and DIS3 were further investigated in rectal adenoma and carcinoma tissues by immunohistochemistry. Results We indentified ten gains and 22 losses in rectal adenoma, and found 25 gains and 14 losses in carcinoma. Gains of 7p21.3-p15.3, 7q22.3-q32.1, 13q13.1-q14.11, 13q21.1-q32.1, 13q32.2-q34, 20p11.21 and 20q11.23-q12 and losses of 17p13.1-p11.2, 18p11.32-p11.21 and 18q11.1-q11.2 were shared by both rectal adenoma and carcinoma. Gains of 1q, 6p21.33-p21.31 and losses of 10p14-p11.21, 14q12-q21.1, 14q22.1-q24.3, 14q31.3-q32.1, 14q32.2-q32.32, 15q15.1-q21.1, 15q22.31 and 15q25.1-q25.2 were only detected in carcinoma but not in adenoma. Copy number and mRNA expression of EFNA1 increased from rectal adenoma to carcinoma. C13orf27 and PMEPA1 with increased copy number in both adenoma and carcinoma were over expressed in rectal cancer tissues. Protein and mRNA expression of GPNMB was significantly higher in cancer tissues than rectal adenoma tissues. Conclusion Our data may help to identify the driving genes involved in the adenoma-carcinoma progression.
    BMC Medical Genomics 11/2012; 5(1):52. DOI:10.1186/1755-8794-5-52 · 3.91 Impact Factor
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    ABSTRACT: To identify potential biomarkers for the prognosis of non-small cell lung cancer (NSCLC) patients by using bronchial brushing specimens. The expression of MCM7, Ki67 and EGFR was evaluated in 494 NSCLC tissues and 174 bronchial brushings using immunohistochemical and immunocytochemical techniques. Associations between protein expression and clinico-pathologic parameters were assessed, and the impact on overall survival (OS) was analyzed. High expression of MCM7, Ki67 and EGFR was detected in 33.3%, 23.5% and 12.7% of tissues and in 52.4%, 52.7% and 20.6% of bronchial brushings, respectively. Expression of MCM7 and Ki67 was associated with squamous cell carcinoma (SCC) in both tissues and bronchial brushings (MCM7: P = 0.0007, 0.00003; Ki67: P < 0.00001, 0.00001). Overexpression of MCM7 in tumor tissues was detected more frequently in poorly differentiated tumors (P = 0.0120) and non-bronchioloalveolar carcinomas (non-BACs) (P = 0.0238). EGFR overexpression was observed in tissues of larger tumors (P = 0.00004) and in bronchial brushings at later stage (P = 0.0262). Kaplan-Meier curves indicated that patients with overexpression of MCM7 or Ki67 had a poorer OS compared to those with low expression for all stages (P < 0.00001, 0.0233) and early-stages (P < 0.00001, 0.0032). In particular, the patients with MCM7 overexpression in bronchial brushings had a poorer prognosis (P = 0.0045). Multivariate Cox regression analysis showed that MCM7 was an independent prognostic indicator both in tissue samples and bronchial brushings. Our data suggest that MCM7 and Ki67 in tumor tissues may be potential markers of a poor prognosis for NSCLC patients. MCM7 in bronchial brushings also showed an independent prognostic value, which may be useful when biopsies are unavailable.
    Lung cancer (Amsterdam, Netherlands) 03/2012; 77(1):176-82. DOI:10.1016/j.lungcan.2012.03.001 · 3.74 Impact Factor
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    ABSTRACT: Aberrant activation of the signal transducer and activator of transcription (Stat)3 and overexpression of polo-like kinase (PLK)1 each have been associated with cancer pathogenesis. The mechanisms and significance of dysregulation of Stat3 and PLK1 in carcinogenesis and cancer progression are unclear. We investigated the relationship between Stat3 and PLK1 and the effects of their dysregulation in esophageal squamous cell carcinoma (ESCC) cells. We used immunoblot, quantitative reverse-transcription polymerase chain reaction, immunochemistry, chromatin immunoprecipitation, mobility shift, and reporter assays to investigate the relationship between Stat3 and PLK1. We used colony formation, fluorescence-activated cell sorting, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, and xenograft tumor assays to determine the effects of increased activation of Stat3 and PLK1 in proliferation and survival of ESCC cells. Stat3 directly activated transcription of PLK1 in esophageal cancer cells and mouse embryonic fibroblast cell NIH3T3. PLK1 then potentiated the expression of Stat3; β-catenin was involved in PLK1-dependent transcriptional activation of Stat3. This mutual regulation between Stat3 and PLK1 was required for proliferation of esophageal cancer cells and resistance to apoptosis in culture and as tumor xenografts in mice. Furthermore, phosphorylation of Stat3 and overexpression of PLK1 were correlated in a subset of ESCC. Stat3 and PLK1 control each other's transcription in a positive feedback loop that contributes to the development of ESCC. Increased activity of Stat3 and overexpression of PLK1 promote survival and proliferation of ESCC cells in culture and in mice.
    Gastroenterology 11/2011; 142(3):521-530.e3. DOI:10.1053/j.gastro.2011.11.023 · 13.93 Impact Factor
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    ABSTRACT: To investigate the molecular mechanisms through which polo-like kinase-1 (PLK1) takes part in anoikis resistance of esophageal squamous cell carcinoma (ESCC) cells. The role of PLK1 in cell anoikis resistance was examined by ectopic gene expression and siRNA-mediated knockdown. Glutathione S-transferase pull-down and co-immunoprecipitation assays were utilized to investigate PLK1-interacting proteins. Electrophoretic mobility shift assay, chromatin immunoprecipitation, and reporter gene assays were carried out to identify the transcription factors responsible for PLK1 expression during anoikis resistance. We found that detachment of ESCC cells triggers the upregulation of PLK1. Elevated PLK1 expression contributes to protection against anoikis in cancer cells through the regulation of β-catenin expression. Moreover, we showed that, through direct binding to the PLK1 promoter, the NF-κB subunit RelA transcriptionally activates PLK1, which inhibits the ubiquitination and degradation of β-catenin. Inhibition of the NF-κB pathway restores the sensitivity of cancer cells to anoikis by downregulating PLK1/β-catenin expression. In addition, RelA gene amplification and protein overexpression was significantly correlated with PLK1 expression in ESCC tissues. Our findings suggest that upregulation of PLK1 triggered by cell detachment is regulated by RelA at the transcriptional level. PLK1 protects esophageal carcinoma cells from anoikis through modulation of β-catenin protein levels by inhibiting their degradation. Taken together, this study reveals critical mechanisms involved in the role of RelA/PLK1/β-catenin in anoikis resistance of ESCC cells.
    Clinical Cancer Research 05/2011; 17(13):4285-95. DOI:10.1158/1078-0432.CCR-10-3236 · 8.19 Impact Factor
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    ABSTRACT: Protein kinase Cι (PKCι) is an atypical PKC isoform and participates in multiple aspects of the transformed phenotype in human cancer cells. We previously reported that frequent amplification and overexpression of PKCι were correlated with lymph node metastasis in primary esophageal squamous cell carcinomas (ESCC). In the present study, short interfering RNA-mediated silencing of PKCι revealed that this enzyme was required for cell migration, invasion, and resistance to anoikis. In vivo experiments showed that PKCι suppression decreased tumor growth in esophageal cancer xenografts and lung metastases in nude mice. At the molecular level, knockdown of PKCι in suspended ESCC cells caused a decrease in S-phase kinase-associated protein 2 (SKP2) that had been reported to promote resistance to anoikis via the PI3K/AKT pathway. AKT phosphorylation was abolished after PKCι suppression, but AKT activation could be refreshed by PKCι upregulation, suggesting that PKCι enhanced cell resistance to anoikis via the PKCι-SKP2-PI3K/AKT pathway. Addition of the proteasome inhibitor MG132 prevented the decrease of SKP2 in PKCι silenced cells, and polyubiquitin-SKP2 was elevated after PKCι depletion, showing that PKCι might regulate the expression of SKP2 through the ubiquitin-proteasome pathway in suspended cells. Furthermore, overexpression of SKP2 in PKCι-downregulated cells restored cell resistance to anoikis. Most importantly, PKCι expression significantly correlated with SKP2 in 133 ESCC tissues (P = 0.031). Taken together, our data show that PKCι promotes tumorigenicity and metastasis of human esophageal cancer and that SKP2 is a candidate downstream effector of PKCι signaling in ESCC.
    Molecular Cancer Research 02/2011; 9(4):390-402. DOI:10.1158/1541-7786.MCR-10-0359 · 4.50 Impact Factor