Publications (58)

  • Yantao Bao · Jia Liu · Jia You · [...] · Songbin Fu
    [Show abstract] [Hide abstract] ABSTRACT: Background: Sei-1 is an oncogene capable of inducing double minute chromosomes (DMs) formation. DMs are hallmarks of amplification and contribute to oncogenesis. However, the mechanism of Sei-1 inducing DMs formation remains unelucidated. Results: DMs formation significantly increased during serial passage in vivo and gradually decreased following culture in vitro. micro nuclei (MN) was found to be responsible for the reduction. Of the DMs-carrying genes, Met was found to be markedly amplified, overexpressed and highly correlated with DMs formation. Inhibition of Met signaling decreased the number of DMs and reduced the amplification of the DMs-carrying genes. We identified a 3.57Mb DMs representing the majority population, which consists of the 1.21 Mb AMP1 from locus 6qA2 and the 2.36 Mb AMP2 from locus 6qA2-3. Materials and methods: We employed NIH-3T3 cell line with Sei-1 overexpression to monitor and characterize DMs in vivo and in vitro. Array comparative genome hybridization (aCGH) and fluorescence in situ hybridization (FISH) were performed to reveal amplification regions and DMs-carrying genes. Metaphase spread was prepared to count the DMs. Western blot and Met inhibition rescue experiments were performed to examine for involvement of altered Met signaling in Sei-1 induced DMs. Genomic walking and PCR were adopted to reveal DMs structure. Conclusions: Met is an important promotor of DMs formation.
    Article · Aug 2016 · Oncotarget
  • Article · Mar 2016 · Cancer Research
  • Conference Paper · Mar 2016
  • Hao Wang · Xueyan Zhang · Wenjing Sun · [...] · Chen Liu
    [Show abstract] [Hide abstract] ABSTRACT: The pathogenesis of colon cancer is unclear. It is proposed that TIM1 has an association with human cancer. The present study aims to investigate the role of TIM1 activation in the inhibition of human colon cancer cells. In this study, human colon cancer cell line, HT29 and T84 cells were cultured. The expression of TIM1 was assessed by real time RT-PCR and Western blotting. The TIM1 on the cancer cells was activated in the culture by adding recombinant TIM4. The chromatin structure at the FasL promoter locus was assessed by chromatin immunoprecipitation. The apoptosis of the cancer cells was assessed by flow cytometry. The results showed that human colon cancer cell lines, HT29 cells and T84 cells, expressed TIM1. Activation of TIM1 by exposing the cells to TIM4 significantly increased the frequency of apoptotic colon cancer cells. The expression of FasL was increased in the cancer cells after treating by TIM4. Blocking Fas or FasL abolished the exposure to TIM4-induced T84 cell apoptosis. In conclusion, HT29 cells and T84 cells express TIM1; activation TIM1 can induce the cancer cell apoptosis. TIM1 may be a novel therapeutic target of colon cancer.
    Article · Feb 2016 · Biochemical and Biophysical Research Communications
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    [Show abstract] [Hide abstract] ABSTRACT: ALK receptor tyrosine kinase has been shown to be a therapeutic target in neuroblastoma. Germline ALK activating mutations are responsible for the majority of hereditary neuroblastoma and somatic ALK activating mutations are also frequently observed in sporadic cases of advanced NB. Crizotinib, a first-line therapy in the treatment of advanced non-small cell lung cancer (NSCLC) harboring ALK rearrangements, demonstrates striking efficacy against ALK-rearranged NB. However, crizotinib fails to effectively inhibit the activity of ALK when activating mutations are present within its kinase domain, as with the F1174L mutation. Here we show that a new ALK inhibitor AZD3463 effectively suppressed the proliferation of NB cell lines with wild type ALK (WT) as well as ALK activating mutations (F1174L and D1091N) by blocking the ALK-mediated PI3K/AKT/mTOR pathway and ultimately induced apoptosis and autophagy. In addition, AZD3463 enhanced the cytotoxic effects of doxorubicin on NB cells. AZD3463 also exhibited significant therapeutic efficacy on the growth of the NB tumors with WT and F1174L activating mutation ALK in orthotopic xenograft mouse models. These results indicate that AZD3463 is a promising therapeutic agent in the treatment of NB.
    Full-text Article · Jan 2016 · Scientific Reports
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    Jie Xu · Peng Liu · Xiangning Meng · [...] · Wenjing Sun
    [Show abstract] [Hide abstract] ABSTRACT: Double minute chromosomes (DMs) are the cytogenetic hallmark of extra-chromosomal genomic amplification. They can well represent the advanced stage of malignancy. However, the mechanisms of DM generation are still not fully understood. Here, the sister chromatid exchange (SCE) was used to determine whether the occurrence of DMs was related to the high genomic instability in human carcinoma cells. We analyzed SCE frequencies in two groups of cell lines: the first group contained DM-positive cell lines such as UACC-1598, SK-PN-DW, and NCI-N87 carcinomas, while the second group comprised DM-negative cell lines including HO-8910, U251, and MGC-803. The data showed that SCE was significantly increased in the DM-positive cells as compared to the DM-negative cells. In addition, there was a positive correlation between the incidence of DMs and the SCE frequency in the UACC-1598, SK-PN-DW, and NCI-N87 carcinoma cells. Because SCE can reflect general genome instability, it is suggested that the DMs are likely to be closely associated with genomic instability in carcinoma cells. Meanwhile, SCE may be involved in the malignant progression of DM-positive cancers.
    Full-text Article · Dec 2015 · Molecular Cytogenetics
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    Dataset: S3 Fig
    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: The efficient transfected in OC cell lines was detected by western blots. (TIF)
    Full-text Dataset · Nov 2015
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    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: Double minute chromosomes (DMs) have important implications for cancer progression because oncogenes frequently amplified on them. We previously detected a functionally undefined gene amplified on DMs, Ribosomal L22-like1 (RPL22L1). The relationship between RPL22L1 and cancer progression is unknown. Here, RPL22L1 was characterized for its role in ovarian cancer (OC) metastasis and its underlying mechanism was examined. DNA copy number and mRNA expression of RPL22L1 in OC cells was analyzed using data obtained from The Cancer Genome Atlas and the Gene Expression Omnibus database. An immunohistochemical analysis of clinical OC specimens was performed and the relationships between expression level and clinicopathological factors were evaluated. Additionally, in vivo and in vitro assays were performed to understand the role of RPL22L1 in OC. RPL22L1 expression was higher in OC specimens than in normal tissues, and its expression level was highly positively correlated with invasion and lymph node metastasis (P < 0.05). RPL22L1 over-expression significantly enhanced intraperitoneal xenograft tumor development in nude mice and promoted invasion and migration in vitro. Additionally, RPL22L1 knockdown remarkably inhibited UACC-1598 cells invasion and migration. Further, RPL22L1 over-expression up-regulated the mesenchymal markers vimentin, fibronectin, and α-SMA, reduced expression of the epithelial markers E-cadherin, α-catenin, and β-catenin. RPL22L1 inhibition reduced expression of vimentin and N-cadherin. These results suggest that RPL22L1 induces epithelial-to-mesenchymal transition (EMT). Our data showed that the DMs amplified gene RPL22L1 is critical in maintaining the aggressive phenotype of OC and in triggering cell metastasis by inducing EMT. It could be employed as a novel prognostic marker and/or effective therapeutic target for OC.
    Full-text Article · Nov 2015 · PLoS ONE
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    Dataset: S1 Fig
    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: DNA amplification levels of RPL22L1 detected by PCR. (TIF)
    Full-text Dataset · Nov 2015
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    Dataset: S2 Fig
    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: Representative pictures of four different degrees of RPL22L1 staining (0–3) in both the nucleus and cytoplasm. (TIF)
    Full-text Dataset · Nov 2015
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    Dataset: S4 Fig
    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: Morphologies of cells were captured under a light microscope. (TIF)
    Full-text Dataset · Nov 2015
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    Dataset: S1 Text
    Nan Wu · Jia Wei · Yuhui Wang · [...] · Yan Jin
    [Show abstract] [Hide abstract] ABSTRACT: Details of primary antibodies. (DOC)
    Full-text Dataset · Nov 2015
  • [Show abstract] [Hide abstract] ABSTRACT: We used a panel of 17 non-small-cell lung cancer cell lines to investigate whether the presence of polymorphisms in the RRM1, ERCC1, ABCB1 and MTHFR genes and alterations in their mRNA expression can affect the in vitro chemosensitivity to cisplatin and gemcitabine. Polymorphisms in these genes were evaluated by direct sequencing. mRNA expression levels were assessed by realtime PCR. In vitro chemosensitivity to cisplatin and gemcitabine was expressed as IC50 values, using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. There was a significant, positive correlation between RRM1 mRNA expression and IC50 values for gemcitabine (r = 0.6533, p = 0.0045), and there was a significant, negative correlation between ABCB1 mRNA expression and IC50 values for cisplatin (r = -0.5459, p = 0.0287). When examining the association between the polymorphisms and IC50, we found that only the MTHFR 1298A>C polymorphism showed a tendency to be more chemosensitive to gemcitabine (p = 0.0440). These in vitro results suggest that mRNA expression levels of the RRM1 and ABCB1 genes may be useful indicators of chemosensitivity to gemcitabine and cisplatin, respectively. The MTHFR 1298A>C polymorphism was associated with gemcitabine chemosensitivity, which require further functional analysis with co-expressed genes and should be explored in prospective clinical studies to determine its potential clinical application as a predictive biomarker. Original submitted 11 February 2014; Revision submitted 3 November 2014.
    Article · Jan 2015 · Pharmacogenomics
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    Full-text Dataset · Dec 2014
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    [Show abstract] [Hide abstract] ABSTRACT: Gene amplification is a frequent manifestation of genomic instability that plays a role in tumour progression and development of drug resistance. It is manifested cytogenetically as extrachromosomal double minutes (DMs) or intrachromosomal homogeneously staining regions (HSRs). To better understand the molecular mechanism by which HSRs and DMs are formed and how they relate to the development of methotrexate (MTX) resistance, we used two model systems of MTX-resistant HT-29 colon cancer cell lines harbouring amplified DHFR primarily in (i) HSRs and (ii) DMs. In DM-containing cells, we found increased expression of non-homologous end joining (NHEJ) proteins. Depletion or inhibition of DNA-PKcs, a key NHEJ protein, caused decreased DHFR amplification, disappearance of DMs, increased formation of micronuclei or nuclear buds, which correlated with the elimination of DHFR, and increased sensitivity to MTX. These findings indicate for the first time that NHEJ plays a specific role in DM formation, and that increased MTX sensitivity of DM-containing cells depleted of DNA-PKcs results from DHFR elimination. Conversely, in HSR-containing cells, we found no significant change in the expression of NHEJ proteins. Depletion of DNA-PKcs had no effect on DHFR amplification and resulted in only a modest increase in sensitivity to MTX. Interestingly, both DM-containing and HSR-containing cells exhibited decreased proliferation upon DNA-PKcs depletion. We demonstrate a novel specific role for NHEJ in the formation of DMs, but not HSRs, in MTX-resistant cells, and that NHEJ may be targeted for the treatment of MTX-resistant colon cancer. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Full-text Article · Dec 2014 · Journal of Medical Genetics
  • [Show abstract] [Hide abstract] ABSTRACT: Gene transcription analysis is important in cancer research, and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) has been demonstrated to be an effective method to evaluate gene transcription in cancer. RT‑qPCR requires an internal reference gene with a consistent level of mRNA transcription across various experimental conditions. However, it has been suggested that different treatments, including anticancer therapy, may influence the transcriptional stability of internal reference genes. Paclitaxel (PTX) and 10‑hydroxycamptothecin (HCPT) are widely used to treat various types of cancer, and a suitable internal reference gene is required in order to analyze the transcription profiles of the cells following treatment. In the current study, the transcriptional stability of 30 candidate reference genes was investigated in cancer cells following treatment with PTX and HCPT. The two ovarian cancer cell lines, UACC‑1598 and SKOV3, were treated with PTX and HCPT for 24 and 48 h, and the transcriptional levels of the candidate reference genes were subsequently evaluated by RT‑qPCR analysis. The transcriptional stability of the selected genes was then analyzed using qbase+ and NormFinder software. A total of 9 genes were demonstrated to exhibit high transcriptional stability and one of these genes, ribosomal protein L13a (RPL13A), was identified to exhibit high transcriptional stability in every group. The current study identified various reference genes suitable under different circumstances, while RPL13A was indicated to be the most suitable reference gene for analyzing the transcription profile of ovarian cancer cells following treatment with PTX and HCPT.
    Article · Dec 2014 · Molecular Medicine Reports
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    Wenjing Sun · Chao Quan · Yun Huang · [...] · Songbin Fu
    [Show abstract] [Hide abstract] ABSTRACT: Figure S2. Double minute chromosomes (DM) production and copy number of DM-carried genes decrease with knock-down of ERK1 and ERK2.
    Full-text Dataset · Nov 2014
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    Wenjing Sun · Chao Quan · Yun Huang · [...] · Songbin Fu
    [Show abstract] [Hide abstract] ABSTRACT: Table S1. siRNA sequence
    Full-text Dataset · Nov 2014
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    Wenjing Sun · Chao Quan · Yun Huang · [...] · Songbin Fu
    [Show abstract] [Hide abstract] ABSTRACT: Figure S1. The numbers of double minute chromosomes (DMs) and copies of DM-carried genes decrease after inhibition of ERK1/2 phosphorylation.
    Full-text Dataset · Nov 2014
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    Wenjing Sun · Chao Quan · Yun Huang · [...] · Songbin Fu
    [Show abstract] [Hide abstract] ABSTRACT: Figure S3. The malignancy of tumour cells is decreased with ERK1 and ERK2 knock-down.
    Full-text Dataset · Nov 2014