Xiu-Ping Liu

Fudan University, Shanghai, Shanghai Shi, China

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Publications (15)51.98 Total impact

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    ABSTRACT: The oligodendroglioma (OG) type of glial cell tumors accounts for 2-5% of primary brain neoplasms and 4-15% of gliomas diagnosed worldwide. Allelic losses on 1p, or on 1p and 19q, correlate with chemotherapy response and good prognosis in OG patients; however, the underlying mechanisms are not yet clearly defined. Therefore, we utilized a quantitative proteomics strategy that combined 8-plex isobaric tags for relative and absolute quantitation (iTRAQ) labeling and two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC/MS/MS) to identify molecular signatures, reveal mechanisms, and develop predictive markers of OG patients with 1p loss of heterozygosity (LOH). An initial screening of four OG patients with 1p LOH and four without were identified, and 449 differentially expressed proteins were quantified, 13 of which were significantly different between the two groups. Analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway suggested that 1p LOH may affect the actin network in OG. The differential expression of four of the 13 candidates (UBA1, ubiquitin-like modifier activating enzyme 1; ATP6V1E1, ATPase, H+ transporting, lysosomal 31kDa, V1 subunit E1; MAP2, microtubule-associated protein 2; and HMGB1, high-mobility group protein B1) was validated in 39 additional OG samples using immunohistochemistry. Decision tree modeling indicated that MAP2 expression is a powerful predictor of 1p LOH. Our results not only demonstrate the utility of iTRAQ-based high-throughput quantitative proteomic analysis in glioma research, but also provide novel markers that may help to reveal the mechanisms of 1p LOH-associated chemosensitivity, and to design diagnostic and prognostic assays and therapeutics for OG.
    Journal of proteomics 10/2012; · 5.07 Impact Factor
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    ABSTRACT: CCAAT enhancer binding protein-α (C/EBP-α) is a transcript factor that regulates adipocyte differentiation and induces apoptosis in hepatic stellate cells (HSCs) in vivo and in vitro. However, the effect of C/EBP-α on hepatocytes in vivo remains unknown. This study investigated whether C/EBP-α exerts different apoptotic effects on hepatocytes and HSCs in vitro and in vivo. An adenovirus vector-expressing C/EBP-α gene was constructed, and a rat hepatic stellate cell lines (HSC-T6) and hepatocytes were transfected. A CCl(4)-induced liver fibrosis model in mice was also utilized. C/EBP-α induced apoptosis in hepatocytes and HSCs, but a significant difference between these cell types was observed in vitro. The mitochondrial pathway was involved in the apoptotic process and was predominant in HSC-T6 apoptosis. In the CCl(4)-induced mice liver fibrosis model, the administration of Ad-C/EBP-α decreased extracellular matrix deposition, including collagen and hydroxyproline content, and γ-GT levels, a marker of liver damage, were reduced significantly. Immunohistochemistry and TUNEL assay results showed an increase of apoptosis in HSCs, but hepatocytes were less affected. C/EBP-α induced differential apoptotic effects in hepatocytes and HSCs in vitro and in vivo. This differential effect could be a potential target for the treatment of hepatic fibrosis with little hepatic toxicity.
    Apoptosis 02/2012; 17(5):492-502. · 4.07 Impact Factor
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    ABSTRACT: Multidrug resistance is the most predominant phenomenon leading to chemotherapy treatment failure in breast cancer patients. Despite many studies having suggested that overexpression of epidermal growth factor receptor (EGFR) is a potent predictor of malignancy in cancers, systematic research of EGFR in multidrug resistant (MDR) breast cancer cells is lacking. In order to clarify the role of EGFR in MDR breast cancer cells, MCF7/Adr expressing relatively higher EGFR, and its parental cell line MCF7 expressing relatively lower EGFR, were chosen for this study. Knockdown of EGFR by siRNA in MCF7/Adr cells showed that EGFR siRNA inhibits cell migration, invasion and proliferation in vitro; converse effects were observed in MCF7 cells transfected with pcDNA3.0-EGFR plasmid. Moreover, we found that EGFR upregulated migration and invasion via EMMPRIN, MMP2 and MMP9 in addition to promoting cell cycle passage via elevation of cyclin D1 and CDK4 in MDR breast cancer cells. Interestingly, MCF7/Adr cells not expressing EGFR showed significant decrease of P-glycoprotein (P-gp) and ABCG2 expression levels, and became more sensitive to treatment of adriamycin (ADR) and paclitaxel (Taxol); the above results indicated that MDR of cancer cells is related to S-phase arrest. In conclusion, EGFR is an important factor enhancing the malignancy of MDR breast cancer cells, partially, inducing MDR. Anti-EGFR therapy may improve outcome in chemorefractory breast cancer patients.
    International Journal of Oncology 07/2011; 39(6):1501-9. · 2.66 Impact Factor
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    ABSTRACT: We aimed to gain a mechanistic understanding of the role of RACK1 in breast carcinoma migration/metastasis. Migration assays were conducted in breast carcinoma cell lines. siRNA targeting RACK1 as well as the Rho kinase inhibitor were also applied. Immunoprecipitation and immunofluorescence were used to study the RACK1/RhoA interaction. GTP-Rho pull-down assays were performed to assess the activation of RhoA. We also conducted immunohistochemistry in 160 breast carcinoma samples. Experiments in vitro showed that RACK1 promotes migration via interaction with RhoA and activation of the RhoA/Rho kinase pathway. Immunohistochemistry in 160 samples revealed that RACK1 is strongly correlated with accepted tumor spread indicators and RhoA (all P < 0.05). Kaplan-Meier survival analysis indicated a correlation between higher RACK1 expression and shorter survival times (P < 0.001). RACK1 is a prognostic factor that promotes breast carcinoma migration/metastasis by interacting with RhoA and activating the RhoA/Rho kinase pathway.
    Breast Cancer Research and Treatment 05/2010; 126(3):555-63. · 4.47 Impact Factor
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    ABSTRACT: We aimed to investigate the expression of RACK1 in breast cancer, evaluate its role in predicting prognosis and compare with commonly used biomarkers: Ki67, ER, PR and HER-2 for patients with breast cancer. The RACK1 expression and its clinical significance were examined in 160 breast carcinoma patients using immunohistochemistry. Correlations of RACK1 expression with other commonly used biomarkers and survival analyses were assessed. Immunohistochemistry results showed that the number of RACK1 cases scoring 0, 1, and 2 were 66, 54, and 40, respectively. RACK1 staining was strongly related to clinical stage, histological grade, Ki67, ER, PR and HER-2 (all p < 0.05). Consistently, all of the cases exhibiting RACK1 staining score 0 were survivors, whereas the majority (55.0%) of those exhibiting RACK1 staining score 2 were deaths. Kaplan-Meier survival analysis of 160 cases revealed a correlation between higher RACK1 expression levels and shorter overall survival times (p < 0.001). Univariate and multivariate analyses revealed that RACK1, tumor size, lymph node metastasis, and HER-2 were independent prognostic factors (all p < 0.05). Interestingly, receiver operator characteristic (ROC) curves showed that the ROC areas for RACK1, Ki67, ER, PR and HER-2 were 0.833, 0.766, 0.446, 0.387, and 0.689, respectively, and the superiority of RACK1 in sensitivity and specificity as biomarker was demonstrated. To our knowledge, it is the first time to investigate the expression of RACK1, and identified that RACK1 is a superior independent biomarker for diagnosis and prognosis comparing with currently widely used diagnostic index in breast carcinoma.
    International Journal of Cancer 12/2009; 127(5):1172-9. · 6.20 Impact Factor
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    ABSTRACT: A yeast two-hybrid system was utilized to identify novel PI3K p110alpha-interacting proteins, of which receptor of activated protein kinase C1 (RACK1) was chosen for successive detailed analyses. Our aim was to investigate the function(s) of RACK1 and its involvement in mechanisms of breast carcinoma proliferation and invasion/metastasis. Experiments in breast carcinoma cell lines stably transfected with RACK1, as well as nude mouse models, showed that RACK1 promotes breast carcinoma proliferation and invasion/metastasis in vitro and in vivo. Conversely, knockdown of RACK1 by siRNA in vitro inhibited proliferation, migration, and invasion. In cell lines stably transfected with RACK1, p-AKT, cyclin D1, cyclin D3, and CD147 expression, as well as MMP2 activity, were elevated. RACK1-induced migration could be inhibited by the addition of Rho-kinase inhibitor. In 160 breast carcinoma cases, survival analyses established that RACK1 is an independent prognostic factor for poor outcome (P < 0.001). In conclusion, RACK1 is an independent prognosis-related factor and promotes breast carcinoma proliferation and invasion/metastasis in vitro and in vivo.
    Breast Cancer Research and Treatment 11/2009; 123(2):375-86. · 4.47 Impact Factor
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    ABSTRACT: Special AT-rich sequence binding protein (SATB) 1 has been proposed to act as a determinant for the acquisition of metastatic activity by controlling expression of a specific set of genes that promote metastatic activity. Here we found that SATB1 expression is upregulated in multidrug-resistant breast cancer cells that exhibit higher invasive potential than the parental cells. Apart from accelerating metastasis and inducing epithelial-mesenchymal transition, SATB1 was demonstrated to confer resistance to both P-glycoprotein-related and P-glycoprotein-non-related drugs on MCF7 cells, which was accompanied by decreasing accumulation of adriamycin in SATB1-overexpressing transfectants. SATB1 depletion could partially reverse the multidrug resistance (MDR) phenotype of MCF7/ADR in vitro and in vivo. The SATB1-induced P-glycoprotein-mediated MDR could be reversed by treatment with anti-P-glycoprotein mAb. Moreover, SATB1 plays an important role in anti-apoptotic activity in MCF7/ADR cells in response to adriamycin treatment, which suggests another mechanism contributing to SATB1-related MDR of breast cancers. These data provide new insights into the mode by which breast tumors acquire the MDR phenotype and also imply a role for SATB1 in this process.
    Cancer Science 09/2009; 101(1):80-6. · 3.48 Impact Factor
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    ABSTRACT: Besides its therapeutic effects, chemotherapeutic agents also enhance the malignancy of treated cancers in clinical situations. Recently, epithelial-mesenchymal transition (EMT) has attracted attention in studies of tumor progression. We aimed to test whether transient Adriamycin treatment induces EMT and apoptosis simultaneously in cancer cells, clarify why the same type of cells responds differentially (i.e., apoptosis, EMT) to Adriamycin treatment, and elucidate the role of Twist1, the master regulator of EMT, in this process. In unsynchronized MCF7 cells or cells synchronized at different phases, apoptosis, EMT, and concurrent events [multidrug resistance (MDR) and tumor invasion] after Adriamycin or/and Twist1 small interfering RNA treatment were examined in vitro and in vivo. The Adriamycin-induced Twist1 expression and the interaction of Twist1 with p53-Mdm2 were examined by immunoblotting and immunoprecipitation, respectively. We showed in vitro that Adriamycin induced EMT and apoptosis simultaneously in a cell cycle-dependent manner. Only the cells undergoing EMT displayed enhanced invasion and MDR. Twist1 depletion completely blocked the mesenchymal transformation, partially reversed MDR, and greatly abolished invasion induced by Adriamycin. Also, we confirmed in vivo that Twist1 RNA interference improved the efficacy of Adriamycin for breast cancers. Further, Twist1 reduction in Adriamycin-treated cells promoted p53-dependent p21 induction and disrupted the association of p53 with Mdm2. Our studies show the diverse responses to Adriamycin treatment in cells at different phases, suggest an unrecognized role of EMT in regulating MDR and invasion, and show the efficacy of Twist1 RNA interference in Adriamycin-based chemotherapies for breast cancer.
    Clinical Cancer Research 04/2009; 15(8):2657-65. · 7.84 Impact Factor
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    ABSTRACT: Lymph-node metastasis is a main factor causing poor prognosis of patients with gastric cancer (GC). In order to determine the genes involved in lymph-node metastasis, we compared primary tumors with their synchronous lymph-node metastases for DNA sequence copy number aberrations (DSCNAs) in 20 patients diagnosed as having intestinal-type GC using comparative genomic hybridization (CGH). The results showed that some DSCNAs (gains at 8q, 13q, 5p, 7 and X, and losses at 1p, 17p, 19, 21q and 22q) were frequently found in both primary tumors and their metastases. However, metastases often contained DSCNAs that were not found in corresponding primary tumors, and gain at 20q12-13 and losses at 21qcen-21, 4q and 14q22-ter were significantly more frequently observed in metastatic lesions than in their primary tumors (10:2, 9:0, 6:0, and 7:0 between metastases and corresponding primary tumors, respectively). Our data indicate that gain at 20q12-13 and losses at 21qcen-21, 4q, and 14q22-ter are involved in lymph-node metastases, and that these chromosomal regions may contain the genes related to lymph-node metastases in intestinal-type GC.
    Pathology - Research and Practice 12/2008; 205(2):105-11. · 1.21 Impact Factor
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    ABSTRACT: Ubiquitin carboxy terminal hydrolase-L1 (UCH-L1) belongs to the UCH proteases family that deubiquitinates ubiquitin-protein conjugates in the ubiquitin-proteasome system. Previous research showed that UCH-L1 was expressed in mouse retinal cells and testicular germ cells, and its function was associated with apoptosis. But it is still unclear whether UCH-L1 is concerned with apoptosis in tumor cells. In order to clarify the role of UCH-L1 in tumor cells, multi-drug resistance (MDR) human breast carcinoma cell line MCF7/Adr, that expresses relatively high UCH-L1, and its parental cell line MCF7, that expresses relatively low UCH-L1, were chosen for this study. We transfected pcDNA3.1-UCH-L1 plasmid and UCH-L1 siRNA into MCF7 and MCF7/Adr cells, respectively. Using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, western blot, Hoechst 33258 staining assay and flow cytometry, we found that over-expression of UCH-L1 in MCF7 cells induced apoptosis. On the other hand, silencing of UCH-L1 in MCF7/Adr cells led to the opposite effect. Moreover, to explore the mechanism underling these observations, we further investigated the expression of phospho-Akt and its downstream signal phospho-IkB-alpha and other signal molecules including Fas, Fas-L, Trail, DR4, DR5, Bax, cytochrome C, active caspase-3, phospho-p53, phospho-Mdm-2, Bcl-2, Bcl-xL, p21 and p27. The results indicated that the process of apoptosis triggered by UCH-L1 is, at least in part, probably through Phosphoinositide 3-kinase (PI3K)/Akt signal pathway. Our findings suggest that modulating the ubiquitination and deubiquitination pathway could be a novel method for tumor therapy.
    International Journal of Oncology 12/2008; 33(5):1037-45. · 2.66 Impact Factor
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    ABSTRACT: Multidrug-resistant cancer cells overexpressing P-glycoprotein (P-gp) display variations in invasive and metastatic ability through the upregulation of the extracellular matrix metalloproteinase (MMP) inducer (CD147). However, the direct linkage between these two proteins is still unclear. We used immunoprecipitation, immunofluorescence analysis, migration and invasion assays, drug sensitivity assay and Western blot to measure the physical and functional interaction between P-gp and CD147. Then we transfected vectors carrying ubiquitin C-terminal hydrolase L1 (UCH-L1) or UCH-L1 siRNA into MCF7 and MCF7/Adr cells, respectively, and investigated the role of UCH-L1 in the regulation of the expression and degradation of P-gp, CD147 and MMP-1, MMP-2, and MMP-9 by quantitative real-time polymerase chain reaction, Western blot and immunoprecipitation. In this paper, we showed that P-gp and CD147 interacted with each other, and that the ubiquitin-proteasome pathway played an important role in the turnover of them. In addition, we found that inhibition of N-glycosylation increased the ubiquitination and degradation of P-gp and CD147, and affected their function. UCH-L1 not only regulated the expression of P-gp, CD147 and MMP-1, MMP-2, and MMP-9, but also the ubiquitination and degradation of P-gp and CD147 in breast cancer cells. Our results demonstrate a mechanism underlying the linkage between multidrug resistance and tumor metastasis, and suggest for the first time that modulating the ubiquitination of P-gp and CD147 might be a novel method for tumor therapy.
    Chemotherapy 02/2008; 54(4):291-301. · 2.07 Impact Factor
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    ABSTRACT: To analyze the correlation of DNA sequence copy number aberrations (DSCNAs)with clinicopathologic parameters in patients with colorectal cancer(CRC). Comparative genomic hybridization (CGH) method was used in analysis of 73 cases with CRC. Statistical analysis was performed using Stat View statistical software package(5.0). Loss of 8pl2-pter and gain of 8q23-qter were linked to nodal metastasis, while loss of 18q12-qter and gain of 8q23-qter were associated with distant organ metastasis at diagnosis and (or) recurrence after surgery. Moreover, losses of 8pl2-pter and 18q12-qter and gain of 8q23-qter were associated significantly with unfavorable prognosis. Multivariate analysis revealed that loss of 18q12-qter was an independent prognostic marker. Our findings indicate that genetic aberrations detected by CGH may predict outcome in patients with CRC, and may provide useful information for clinical treatment. Comparative genomic hybridization;
    Zhonghua zhong liu za zhi [Chinese journal of oncology] 06/2007; 29(5):355-9.
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    ABSTRACT: To obtain comprehensive information regarding the correlation between genomic changes and clinicopathological parameters such as disease stage, metastases, and survival, we investigated genomic changes by comparative genomic hybridization (CGH) in 73 patients with colorectal cancer (CRC), and assessed the associations of such charges with clinicopathological parameters. Gains of 8q21-22, 13q21-31 and 20q12-qter and loss of 17p12-pter were detected in >50% of stage I tumors. Gain of 8q23-qter and losses of 8p12-pter and 18q12-qter were observed more frequently in stage III/IV tumors than in stage I tumors (all P<0.05). Loss of 8p12-pter and gain of 8q23-qter were linked to nodal metastasis (all P<0.05). Loss of 18q12-qter and gain of 8q23-qter were associated with distant organ metastasis at diagnosis and/or recurrence after surgery (all P<0.05). Moreover, losses of 8p12-pter and 18q12-qter and gains of 8q23 and 8q24-qter were associated significantly with unfavorable prognosis (all P<0.05). Furthermore, combined examination of the above four changes can provide a more accurate assessment for patient's prognosis. Specifically, 11 of 19 patients with these four changes died, but only 1 of 21 cases without these four changes died during the follow-up period (P<0.0001). Multivariate analysis revealed that loss of 18q12-qter is an independent prognostic marker (P=0.031). Our findings indicate that genetic aberrations detected by CGH may predict outcome in patients with CRC.
    Oncology Reports 02/2007; 17(1):261-7. · 2.30 Impact Factor
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    ABSTRACT: To data, there have been no comprehensive cytogenetic studies of mucinous colorectal carcinomas (MUCs). We used comparative genomic hybridization (CGH) and laser scanning cytometry (LSC), to analyze cytogenetic changes in 21 MUCs and to compare the results with those of our previous study of 60 non-MUCs. Six of 21 MUCs were aneuploid and 15 were diploid. Gains of 13q, 8q, 2q, 12p and 18p were more frequent aberrations. Recurrent decreases in DNA copy number were found frequently at 17p, 22q, 1p, 16p and 8p. Amplifications of 8q, 5p, 12, 18p, 13q and 20p were observed in aneuploid tumors. The average number of DNA sequence copy number aberrations (DSCNAs) was significantly higher in aneuploid MUCs than in diploid ones. Aneuploid MUCs were clinicopathologically more aggressive, with greater lymph node involvement, distant organ metastasis, recurrence after surgery, higher stage and poorer prognoses. Gain or amplification of 18p was detected in 5 of 6 aneuploid MUCs but not in diploid MUCs or non-MUCs. When the average number of DSCNAs was compared among MUCs and well, moderately, and poorly differentiated adenocarcinomas, the average number of DSCNAs was significantly lower in diploid MUCs; however, with aneuploid tumors, the average number of DSCNAs in MUCs was similar to that in poorly differentiated adenocarcinomas but higher than that in well and moderately differentiated cancers. Moreover, tumor cells were well differentiated in diploid MUCs but poorly differentiated in aneuploid MUCs. These data suggest that MUCs have two types with different genetic pathways, histologic characteristics, and behavior.
    International Journal of Oncology 10/2004; 25(3):615-21. · 2.66 Impact Factor
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    ABSTRACT: Matrilysin is known to play an important role in tumor invasion, but it is not known yet whether there is a direct relationship between matrilysin expression and cell proliferation. Therefore, we compared expression of matrilysin with expression of Ki-67, a marker of cell proliferation, at different tumor areas in 130 advanced gastric carcinomas. Both matrilysin and Ki-67 were distributed heterogeneously in tumor tissue. Matrilysin frequently was expressed at the invasive front, whereas Ki-67-positive cells frequently were located both at the tumor surface and in central tumor cell nests. The patterns of gastric cancer cell invasion into the surrounding tissues are described as alpha-infiltration, beta-infiltration, and gamma-infiltration, respectively, according to the guidelines of the Japanese Research Society for Gastric Cancer Study. The mean matrilysin labeling index (LI) of gamma-infiltration tumors at the invasive front was significantly greater than that of alpha- and beta-infiltration tumors (P =.01). In contrast to the matrilysin LI, the mean Ki-67 LI of gamma-infiltration tumors was significantly lower than that of alpha- and beta-infiltration tumors (P =.02). Moreover, Ki-67 antigen was absent in matrilysin-positive tumor cells and vice versa. We concluded that matrilysin expression was related inversely with proliferative activity of tumor cells and that matrilysin expression could possibly serve as a useful marker of tumor invasion.
    Human Pathlogy 08/2002; 33(7):741-7. · 2.84 Impact Factor