Jun Gan

Fudan University, Shanghai, Shanghai Shi, China

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Publications (8)19.83 Total impact

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    ABSTRACT: Long non-coding RNAs (lncRNAs), which have evolved as important gene expression modulators, are involved in human malignancies. The down-regulation of lncRNA growth arrest specific transcript 5 (GAS5) has been reported in several cancers, however, the underlying mechanism of lncRNA GAS5 in stomach cancer is poorly understood. In this study, we found that lncRNA GAS5 had lower expression in stomach cancer tissues than the normal counterparts. lncRNA GAS5 was shown to interact with Y-box binding protein 1 (YBX1), and lncRNA GAS5 knockdown was shown to accelerate YBX1 protein turnover without affecting YBX1 transcription. lncRNA GAS5 down-regulation reduced the YBX1 protein level, which decreased YBX1-transactivated p21 expression and abolished G1 phase cell cycle arrest in stomach cancer. These results delineate a novel mechanism of lncRNA GAS5 in suppressing stomach carcinogenesis, and the lncRNA GAS5/YBX1/p21 pathway we discovered may provide useful targets for developing lncRNA-based therapies for stomach cancer.
    Preview · Article · May 2015 · Scientific Reports
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    ABSTRACT: As a transcriptional factor, Nur77 has sparked interests across different research fields in recent years. A number of studies have demonstrated the functional complexity of Nur77 in mediating survival/apoptosis in a variety of cells, including tumor cells. Conflicting observations also exist in clinical reports, in that TR3 behaves like an oncogene in tumors of the GI tract, lung, and breast, that is negatively associated with tumor stage and patient prognosis; while functions as a tumor suppressor gene in malignancies of the hematological and lymphatic system, skin, and ovary whose malfunction results in carcinogenesis. This chapter summarizes the apparent opposing effects of Nur77 on cells and explicates the mechanisms that determine the functional preference of Nur77. We conclude that in addition to cell type and agent context, other factors such as cellular localization, signaling pathway, and posttranslational modification also determine the final effects of Nur77 on cells.
    No preview · Article · Nov 2014 · International review of cell and molecular biology
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    ABSTRACT: Background: Vascular endothelial growth factor-C (VEGF-C), which contributes to lymphatic metastasis (LM) in malignant disease, is one of the most important factors involved in physical and pathological lymphangiogenesis. Some VEGF-C related factors such as sine oculis homeobox homolog (SIX) 1, contactin (CNTN) 1 and dual specificity phosphatase (DUSP) 6 have been extensively studied in malignancies, but their expression levels and associations have still to be elucidated in stomach cancer. Methods: We detected their expression levels in 30 paired stomach cancer tissues using quantitative real-time reverse transcription-PCR (qRT-PCR). The expression and clinical significance of each factor was analyzed using Wilcoxon signed rank sum test. The correlation among all the factors was performed by Spearman rank correlation analysis. Results: The results suggest that VEGF-C and CNTN1 are significantly correlated with tumor size, SIX1 with the age and CNTN1 also with the cTNM stage. There are significant correlations of expression levels among VEGF-C, SIX1, CNTN1 and DUSP6. Conclusions: There exists an important regulatory crosstalk involving SIX1, VEGF-C, CNTN1 and DUSP6 in stomach cancer.
    No preview · Article · Mar 2014 · Asian Pacific journal of cancer prevention: APJCP
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    ABSTRACT: Amine-capped γ-Fe2O3 nanoparticles were prepared by a simple one-step chemical solution method. By changing the type of iron salts, the phase composition and morphology of the samples were adjusted. The resultant products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The magnetic properties were also studied. Triethanolamine (TEA) plays an important role in the formation of magnetic structures. It can act as a precipitator, structure-directing agent, and surface-functionalizing agent. Successful attachment of amine groups to the surface of the magnetic nanoparticles was characterized.
    No preview · Article · Jun 2013 · Industrial & Engineering Chemistry Research
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    ABSTRACT: Defective immune function is an important cause of tumor development. Accumulation of myeloid-derived suppressor cell (MDSC) associated with inhibition of dendritic cell (DC) function is one of the major immunological abnormalities in cancer. However, the molecular mechanism of the phenomenon remains unclear. We evaluated T cell stimulatory activity and interleukin (IL)-12 production of DC in a mouse model of liver cancer (hepatocellular carcinoma [HCC] mice). Then we detected the frequency of MDSC in spleen, peripheral blood (PB), lymph node (LN) and tumor tissue of HCC mice and its potential mechanisms. We also evaluated IL-10 production of MDSC and mechanism by which MDSC inhibit DC function. Toll-like receptor (TLR)-ligand (LPS, CpG, poly(I:C))-induced IL-12 production of DC was decreased in HCC mice compared with control. The T cell stimulatory activity of DC was lower in HCC mice than in controls. Meanwhile, an increase in the frequency of MDSC in tumor development was detected in spleen, PB, LN and tumor, and the IL-10 levels were higher in HCC mice derived MDSC than in control. Furthermore, the MDSC inhibited TLR-ligand-induced IL-12 production of DC by IL-10 production and suppressed T cell stimulatory activity of DC. Finally, we demonstrated that the increase in the frequency of MDSC was mediated by MyD88-NF-kB pathway. Our study suggests a new role for MDSCs in HCC development by suppressing host immune responses, and these findings have important implications when designing immunotherapy protocols.
    No preview · Article · Feb 2011 · Scandinavian Journal of Gastroenterology
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    ABSTRACT: Novel silica-coated iron-carbon composite particles were prepared to be used in the targeting therapy as a drug carrier. The composite particles with diameter of 200-300 nm were obtained successfully via high-energy planetary ball milling and hydrogen reduction processes. The composite particles possess the advantages of activated carbon and magnetic Fe, exhibiting excellent drug adsorption and desorption abilities as well as powerfully magnetic targeting. In in vivo experiment, (99m)TcO(4)-adsorbed composite particles showed prominent biodistribution in the left hepatic lobe of pigs under the control of an external magnetic field. The amount of doxorubicin content of hepatic tissue was 23.8 times higher in targeted area of the left lobe than that in the nontargeted area of the right lobe when doxorubicin-adsorbed composite particles were infused intra-arterially. These results also suggest that the composite particles could penetrate through the capillary wall around tissue interstitium and hepatic cells under the driving of an external magnetic force in targeting area, indicating that the novel silica-coated iron-carbon composite particles could be a potential application in targeted treatment for some kinds of tumor as an effective drug carrier.
    No preview · Article · Sep 2008 · Journal of Biomedical Materials Research Part A
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    ABSTRACT: To observe the pharmacokinetics of adriamycin-adsorbing nanometric activated carbon in intralymphatic chemotherapy. Two ml of suspension of activated carbon with the diameter of 21 nm was mixed with adriamycin 5 mg. Eighteen dogs were randomly divided into 6 equal groups. The above mentioned mixture was injected subserosally to the anterior wall of gastric antrum of the dogs. Thirty minutes, 1 h, 2 h, 1 day, and 3 days after the injection the gastroepiploic lymph nodes of the Groups 1 - 5 were obtained. And Group 6 underwent extraction of venous blood samples 5, 15, 30, 60, 120, and 240 minutes after the injection and extraction of thoracic duct fluid 5, 15, 30, 60, 120, 240, and 360 minutes after the injection. The adriamycin concentrations at different time points were determined by mass spectrometer. The lymphatic vessels and nodes at the gastric wall were observed by the naked eyes. Black tiny lymphatic vessels and lymph nodes were visualized around the injection areas immediately after the injection. Adriamycin content could be detected 30 min after the injection and lasted for 72 h at high levels with the peak content of (84.6 +/- 2.0) microg per gram tissue at 60 min in the perilymph node of gastroepiploic artery. The adriamycin concentration in the lymph fluid of thoracic duct reached the top level of 162.5 ng/ml 30 min after the injection, and then decreased slowly. Adriamycin could be still detected in lymph fluid 6 h after injection. No trace of adriamycin was found in the blood at any time points. The content of adriamycin can keep high and last long in the drainage of lymph node and lymph fluid in the treatment of intralymphatic chemotherapy using adriamycin-adsorbing nanometric activated carbon.
    No preview · Article · Sep 2008 · Zhonghua yi xue za zhi
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    ABSTRACT: To evaluate the effect of a novel blockade technique for gastric cancer on blood-borne metastasis of gastric cancer cells to portal vein. Twenty-three cases of gastric cancer were divided into routine operation group (8 cases intraoperatively without blockade technique) and blockade group (15 cases with blockade technique). Blood samples from portal vein pre- and intraoperatively, as well as gastroepiploic vein limited within the blockade area were obtained to detect CK19 mRNA expression by using RT-PCR technique. Before the dissection of gastric lesion, the overall positive rate of CK19 mRNA expression in portal vein blood is 34.7% (9/23), including 37.5% (3/8) in routine operation group and 33.3% (5/15) in blockade group. While the course of tumor resection, those positive rates were 87.5% (7/8) in routine operation group and 6.7% (1/15) in blockade group respectively (P < 0.05). CK19 mRNA expression in the right gastroepiploic venous blood limited within the blocking area was all positive in 15 cases of blockade group. This blockade technique can be used effectively to block the intraoperative spread of gastric cancer cells, thus prevent blood-borne metastasis due to operative manipulation.
    No preview · Article · Nov 2004 · Zhonghua wai ke za zhi [Chinese journal of surgery]