Qiuran Xu

Shanghai Jiao Tong University, Shanghai, Shanghai Shi, China

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Publications (7)21 Total impact

  • Xin Liu · Shuda Chen · Jianfeng Tu · Wenwei Cai · Qiuran Xu
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    ABSTRACT: Heat shock protein (HSP)90 functions as a general oncogene by targeting several well-known oncoproteins for ubiquination and proteasomal degradation. However, the clinical significance of HSP90, as well as the mechanisms responsible for the tumor-promoting effects of HSP90 in hepatocellular carcinoma (HCC) remain unclear. In this study, HSP90 and hypoxia-inducible factor (HIF)-1α expression in 60 samples of HCC tissues and matched normal tumor-adjacent tissue were assessed using immunohistochemistry (IHC) or western blot analysis. Flow cytometry, BrdU cell proliferation assay, caspase-3/7 activity assay and MTT assay were used to detect the apoptosis and proliferation of the HCC cells. The regulatory effect of HSP90 on HIF-1α in the HCC cells was confirmed by immunofluorescence staining, western blot analysis and RT-qPCR. The interaction between HIF-1α and HSP90 was analyzed by co-immunoprecipitation. A subcutaneous tumor xenograft model in nude mice was established and TUNEL assay was performed to evaluate cancer cell apoptosis and growth in vivo. We found that HSP90 expression was higher in the HCC tissues than in the normal tissues and that a high HSP90 expression correlated with poor clinicopathological characteristics, including venous infiltration, an advanced TNM stage and high pathological grading. Furthermore, we confirmed that patients with a negative expression of HSP90 had an improved 3-year survival, and that HSP90 was an independent factor for predicting the prognosis of patients with HCC. We demonstrated that HSP90 promoted HCC by inhibiting apoptosis and promoting cancer cell growth. Pearson's correlation coefficient analysis indicated that HSP90 expression positively correlated with HIF-1α protein expression in the HCC tissues. Furthermore, we found that HSP90 regulated HIF-1α protein abundance by inhibiting the ubiquitination and proteasomal degradation of HIF-1α in HCC cells. Additionally, the upregulation of HIF-1α expression partially abrogated HSP90 siRNA-induced HCC cell growth arrest and apoptosis in vitro and in vivo. These results indicate that HSP90 may be used as a prognostic marker and that HIF-1α may be one of the potential therapeutic targets of HSP90 in HCC.
    No preview · Article · Feb 2016 · International Journal of Molecular Medicine
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    ABSTRACT: Human hepatocellular carcinoma (HCC) is a highly invasive tumor with frequent distant metastasis, which is the main cause for the poor prognosis. However, the mechanisms for metastasis remain poorly investigated. MicroRNAs (miRNAs) have been implicated in HCC progression. MicroRNA-122 (miR-122) is considered as a tumor suppressor in human cancer. In the present study, miR-122 expression was found to be significantly lower in HCC than the level in normal tumor-adjacent tissues. miR-122 was clearly silenced or downregulated in five HCC cell lines (HepG2, Hep3B, MHCC97H, Huh7 and SMMC-7721) compared with normal hepatocytes (LO2). HCC patients with low expression of miR-122 had a poor 3-year survival. Univariate analysis and multivariate Cox regression analysis indicated that miR-122 is an independent prognostic factor in HCC. Downregulation of miR-122 promoted proliferation and inhibited apoptosis in Hep3B cells. We found that the public miRNA database (TargetScan) predicted that PKM2 may be a target for miR-122, and the 3'-untranslated region (3'-UTR) of PKM2 contains a highly conserved binding site for miR-122. To identify this, pre-miR-122/anti-miR-122 were respectively transfected into the Hep3B cell line. We found that miR-122 overexpression significantly reduced the level of PKM2. Moreover, knockdown of PKM2 significantly increased miR-122 inhibitor-mediated Hep3B cell apoptosis and reduced miR-122 inhibitor-mediated Hep3B cell migration and invasion. Moreover, re-expression of PKM2 partially abrogated miR-122-induced HCC cell growth arrest and apoptosis in vivo. In conclusion, miR-122 serves as a prognostic biomarker and induces apoptosis and growth arrest by downregulating PKM2 in HCC.
    No preview · Article · Aug 2015 · Oncology Reports
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    Qiuran Xu · Xin Liu · Xin Zheng · Yingmin Yao · Qingguang Liu
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    ABSTRACT: Hedgehog (Hh) signaling and the pyruvate kinase isoenzyme M2 (PKM2 or M2-PK) are often involved in tumorigenesis and growth. Aberrant activation of Hh signaling is found in a variety of malignancies. In tumor cells, PKM2 determines whether glucose is used for the synthesis of cellular building blocks or the production of lactate for energy regeneration; it associated with the Warburg effect. Gli1 is a downstream molecule of the Hh signaling pathway; however, the association between Hh signaling and PKM2 is not well understood. In the present study, it was identified that PKM2 and Gli1 expression levels were significantly elevated in hepatocellular carcinoma (HCC) compared with para-carcinoma. In vitro study revealed that overexpression of PKM2 in HepG2 cells upregulated the transcription of Gli1, while the ablation of PKM2 by shRNA caused the downregulation of Gli1 gene expression. Gli1 transcription could be rescued by PKM2. Overall, these findings suggest that PKM2 is a regulator of Gli1 gene expression in HCC, and may contribute to tumorigenesis through Gli1.
    Preview · Article · Nov 2014 · Oncology letters
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    ABSTRACT: The aberrant activation of the Hedgehog (Hh) signaling pathway has been implicated in a variety of malignancies, including hepatocellular carcinoma (HCC). The mammalian 5' adenosine monophosphate-activated protein kinase (AMPK) plays a crucial role in cellular energy homeostasis. However, the interaction between the Hh and AMPK signaling pathways has not been investigated to date. In the present study, to the best of our knowlege, we report for the first time the negative regulation of glioma-associated oncogene 1 (Gli1), an important downstream effector of Hh, by the AMPK signal transduction pathway. Immunoprecipitation and GST-pull down assay showed a direct interaction between AMPK and Gli1. The overexpression of AMPK induced the downregulation of Gli1 expression, while the knockdown of AMPK upregulated Gli1 expression in a relatively short period of time (24 h or less). Our data suggest that AMPK may function as an upstream molecule that regulates Gli1 expression. Therefore, AMPK may play a role in the Hh signaling pathway, through which it regulates tumorigenesis.
    Preview · Article · Jul 2014 · International Journal of Molecular Medicine
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    ABSTRACT: Histone H2B O-GlcNAcylation is an important post-translational modification of chromatin during gene transcription. However, how this epigenetic modification is regulated remains unclear. Here we found that the energy-sensing adenosine-monophosphate-activated protein kinase (AMPK) could suppress histone H2B O-GlcNAcylation. AMPK directly phosphorylates O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT). Although this phosphorylation does not regulate the enzymatic activity of OGT, it inhibits OGT–chromatin association, histone O-GlcNAcylation and gene transcription. Conversely, OGT also O-GlcNAcylates AMPK and positively regulates AMPK activity, creating a feedback loop. Taken together, these results reveal a crosstalk between the LKB1-AMPK and the hexosamine biosynthesis (HBP)-OGT pathways, which coordinate together for the sensing of nutrient state and regulation of gene transcription.
    Full-text · Article · Apr 2014 · Nucleic Acids Research
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    ABSTRACT: The Hedgehog (Hh) pathway is an evolutionarily conserved signaling mechanism that controls many aspects of cell differentiation and the development of tissues and organs during embryogenesis. Early investigations have focused on the effects of Hh activity on the development of organs including skin, gut, the nervous system and bone. However, in addition to normal developmental processes, these investigations also found that Hh signaling is involved in aberrant proliferation and malignant transformation. Consequently, the role of Hh in cancer pathology, and its modulation by environmental factors is the subject of many investigations. Numerous environmental toxins, alcohol, and hepatitis viruses can cause hepatocellular carcinoma (HCC), which is the most common form of liver cancer. Significant hyperactivation of Hh signaling has been observed in liver injury and cirrhosis which often leads to the development of HCC lesions. Moreover, Hh activity plays an important role in the progression of HCC. Here, we review findings relevant to our understanding of the role of Hh signaling in HCC pathogenesis.
    Preview · Article · Aug 2013 · Oncology Reports
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    ABSTRACT: The aim of the present study was to analyze the mRNA and protein expression of glioma-associated oncogene 1 (Gli1) in hepatocellular carcinoma (HCC) and its correlation with sonic hedgehog (Shh), one of the ligands of hedgehog (Hh) signaling, and two epithelial-mesenchymal transition (EMT) markers, E-cadherin and S100a4. We also investigated the potential crosstalk between Hh signaling and EMT in HCC. Paired HCC and normal tumor-adjacent tissues were freshly collected from 30 primary HCC patients. Gli1 expression at both the mRNA and protein level was examined by reverse transcription-polymerase chain reaction and immunohistochemistry. The protein expression of Shh, E-cadherin and S100a4 was evaluated by immunohistochemistry to identify correlations with Gli1. The mRNA and protein expression of Gli1 was significantly up-regulated in the HCC tumor tissues compared to the normal tumor-adjacent tissues (P<0.01, respectively). Gli1 protein expression in HCC was closely correlated with liver cirrhosis (r=0.460, P=0.011<0.05), intrahepatic metastases (r=0.399, P=0.029<0.05), portal vein invasion (r=0.367, P=0.046<0.05), high Edmonson-Steiner classification (r=0.391, P=0.032<0.05) and advanced TNM stage (r=0.416, P=0.022<0.05). In HCC tissues, Gli1 protein expression was positively correlated with Shh (r=0.584, P=0.001<0.05) and S100a4 (r=0.49, P=0.006<0.05), and negatively correlated with E-cadherin (r=-0.439, P=0.015<0.05). Gli1 was found to be up-regulated in HCC tissues and closely correlated with clinicopathological characteristics, indicating the enhanced metastatic potential of HCC. Furthermore, the increased expression of Gli1 in HCC cells may be attributed to Shh produced aberrantly by the cells themselves. Finally, Gli1 may play an important role in HCC invasion and metastasis by inducing EMT.
    Full-text · Article · Nov 2010 · Molecular Medicine Reports

Publication Stats

50 Citations
21.00 Total Impact Points

Institutions

  • 2013-2014
    • Shanghai Jiao Tong University
      Shanghai, Shanghai Shi, China
  • 2010-2014
    • Xi'an Jiaotong University
      • Department of Hepatobiliary Surgery
      Ch’ang-an, Shaanxi, China