Publications by authors named "Zhi Xian Sun"

Although (Nichols, 1926) has been treated valid since it was described, its morphology remains vague, especially when comparing it with another similar species, (Yao & Yang, 1977). In this study, the types of both species were examined and also compared with several lots of specimens from a wide geographical range: there is no significant difference in morphology between them. Additionally, molecular evidence supported by mitochondrial gene sequence also showed low genetic distance in between.

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Artesunate, a remarkable antimalarial agent, also reveals profound cytotoxic activity. In the present investigation, we compared the anticancer effects of artesunate on three colorectal cancer cell lines and analyzed the relationship between drug sensitivity and malignant phenotype of the tumor cells. The findings are as follows: poorly-differentiated was colorectal cancer cell line CLY showing nuclear beta-catenin accumulation and loss of E-cadherin; moderately-differentiated were Lovo cells with cytoplasmic distribution of the two proteins; and well-differentiated were HT-29 cells with membranous localization of them.

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Aim: Investigate the molecular mechanism of regulating survivin expression and related signal transduction pathway, molecular cascade reaction and biological effects in activated PBMC.

Methods: The expression of survivin and related proteins were detected by Western blot in PBMC stimulated by PHA and rhIL-2 with or without JAK inhibitor-AG490 treatment, and FCM was performed to analyze cell cycle and cell division.

Results: Our results indicated that molecular and cellular reactions in PBMC activated by PHA and rhIL-2 were dependent on time series.

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Artesunate (ART), a remarkable antimalarial agent, also inhibited the growth of human colorectal carcinoma. As determined by MTT assay, flow cytometry analysis on apoptosis and indirect immunofluorescence analysis on the proliferation-associated marker Ki67, ART suppressed the proliferation and promoted the apoptosis of colorectal cancer cells in a dose-dependent manner. Furthermore, immunofluorescence analysis on beta-catenin and RT-PCR analysis on Wnt/beta-catenin target genes demonstrated ART translocated beta-catenin from nucleus to adherent junctions of membrane and reduced transcription mediated by beta-catenin.

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Colorectal cancer (CRC) with liver metastasis is a fatal disease with rapid progression and poor patient outcome. However, the molecular mechanism involved in liver metastasis of CRC remains essentially unknown, largely because of the presence of few available CRC cell lines with liver metastasis origin and spontaneous metastatic potentials in nude mice. In this study, we established a novel metastatic CRC cell line, CLY, derived from liver metastasis of a 64-year-old Chinese CRC patient.

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Background & Objective: Proteasome inhibitor, which can induce apoptosis in various tumor cells, is a kind of potential antitumor drug. This study was to identify the proteins involved in G(2)/M arrest of leukemia cell line HL-60 exposed to proteasome inhibitor MG132 by proteomic techniques.

Methods: Flow cytometry was used to examine cell cycle of HL-60 cells exposed to 2.

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The microRNAs (miRNAs) are an extensive class of small noncoding RNAs (18-25 nucleotides) with important roles in the regulation of gene expression. Although a large number of miRNAs have been identified in a variety of eukaryotic systems, the function of the vast majority of these molecules remains unknown. To study the functions of miRNAs, it is crucial to determine their spatial and temporal expression patterns.

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To learn the variation in the gene for UGT1A1 enzyme, the genetic mechanism in a Chinese Han nationality family suffered from Gilbert's syndrome was studied. At first, genomic DNA from peripheral blood of the sufferer in this family was used for amplifying all of the five exons of the UGT1A1 gene by PCR, and then direct sequencing of the PCR product was applied to analyze gene mutation. The results showed that there existed a G-->A homozygous transition at nucleotide 211 leading the substitution of arginine for glycine at position 71 of corresponding protein product (G71R) and a T-->G homozygous transition at nucleotide 1456 leading the substitution of aspartic acid for tyrosine at position 486 of corresponding protein product (Y486D).

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The promyelocytic leukemia (PML) can selectively and dynamically recruit a number of proteins including p53 to form a sub-nuclear multiprotein chamber named PML-NBs. In DNA damage response, p53 is recruited into PML-NBs and modified by phosphorylations and acetylations, which in turn potentiate its transcriptional and pro-apoptotic activities. In contrast, in carcinoma cells, the role of PML in the irradiation induced p53-mediated apoptosis is not precisely understood.

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Human telomeric repeat binding factor 1(TRF1) contains one Myb-type DNA-binding repeat and an amino-terminal acidic domain. It can bind to the duplex array of TTAGGG repeats at chromosome ends and is shown to be important in preserving genomic stability, maintaining cell proliferative capacity, and blocking the activation of DNA-damage cell cycle checkpoints. Interestingly, the double strand DNA breaks sensor ATM interacts with and phosphorylates Pin2/TRF1 and inhibits its function after DNA damage.

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Background & Objective: The expression of Survivin in cancer cells highly correlates with that of human telomerase reverse transcriptase (hTERT). Both of them are ideal targets for cancer gene therapy. This study aimed to clarify if they regulate each other in cancer cells.

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Aim: To prepare and characterize anti-human beta-Netrin antibodies.

Methods: B cell dominant epitopes of human beta-Netrin C-terminal 114 amino acid sequences were predicated by the GoldKey software. One of the epitopes was synthesized and coupled with bovine serum album (BSA) by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC).

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To investigate the function and molecular mechanism of p21(WAF1/Cip-1) expression in MOLT-4 cells induced by HDAC inhibitor TSA, the expression pattern of p21(WAF1/Cip-1) and the distribution of cell cycle in TSA treated cells were analyzed. The results showed that TSA could effectively induce G(2)/M arrest and apoptosis of MOLT-4 cells. Kinetic experiments demonstrated that p21(WAF1/Cip-1) were upregulated quickly before cell arrested in G(2)/M and began decreasing at the early stage of apoptosis.

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Background & Objective: Proteasome inhibitor is a kind of potential anti-tumor drug,it can induce apoptosis in various tumor cells. This study was designed to investigate the molecular mechanism of apoptosis and G(2)/M arrest in leukemia cell line HL-60 induced by proteasome inhibitor MG132 (Z-Leu-Leu-Leu-CHO).

Methods: Apoptosis in HL-60 cells was observed under fluorescent microscope, flow cytometry and immunoblot were used to analyze cell apoptosis, cell cycle arrest, and the mechanisms.

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Background & Objective: Papillary thyroid carcinoma is characterized by RET (rearranged during transfection)/PTC (papillary thyroid carcinoma) rearrangements. However, the function of RET/PTC in carcino- genesis is not well understood. This study was designed to investigate the interaction between DNA double-strand break sensor ATM (mutated in ataxia telangiectasia) kinase and PTC1, a rearranged form of proto-oncogene ret, to explore the role of ret rearrangements in carcinogenesis.

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Background & Objective: Specific gene expression plays an important role in cancer gene therapy. Construction of specific expression vector is the basis of cancer gene therapy. This study was conducted to explore the expression specificity of osm (oncostatin M) gene driven by human telomerase reverse transcriptase (hTERT) gene promoter in tumor cells with telomerase activity and to investigate the growth inhibitory capability of expression of osm gene on telomerase-positive tumor cells.

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Glycophorin A (GPA) is one of the important molecular markers in studies of somatic cell mutations. To investigate the relationship between the gamma-irradiation and the frequency of GPA variation, the frequency of variant erythrocytes at the GPA locus was determined in peripheral blood of 3 subjects with accidental whole-body gamma-irradiation. The biological dose of individuals was 2.

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Caspase-3 Gene Activity in Radiation-induced Apoptosis.

Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai)

January 1999

Previous experiments indicated that caspase-3 was a mediator of ionizing radiation(IR)-induced apoptosis in U937 cells. In present study the caspase-3 activity in IR-induced apoptosis was further measured by analyzing the Ac-DEVD-p-nitroanilide cleaving activity and results showed that caspase-3 activity increased in accordance to the development of apoptosis and reached peak at 6 h post-irradiation. However northern blot analysis showed that the expression of caspase-3 was not changed while Western blot found that the active P20 subunit concentration increased and from 3 h post-irradiation active P17 subunit also increased.

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Expression, Purification and in vitro Activity of Apoptin.

Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai)

January 2001

A novel protein named apoptin induces a p53-independent, Bcl-2 insensitive type apoptosis in various human tumor cells but not in normal cells. Apoptin is considered to be a promising candidate for safe and effective anti-tumortherapy. Moreover, apoptin may be important for fundamental studies on molecularbasis of apoptosis and cancer.

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Effects to HeLa Cells of the Inhibition of Survivin by Antisense RNA.

Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai)

January 2001

To study the function of survivin in cancer cells, survivin cDNA was amplified from HeLa cells by RT-PCR. Then the coding fragment was subcloned into an inducible eukaryotic expression plasmid pHC in reverse direction.The obtained plasmid pHSC was transfected into HeLa cells by Lipofectamine.

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