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In the study, a gene encoding Tat protein N terminal 1- 21 amino acid residues-deleted mutant (Tat22-101) was amplified by PCR from a full length Tat gene of human immunodeficiency virus type 1, and the prokaryotic expression plasmid pET32a-Tat22-101 was constructed. After identification by digestion with endonucleases and sequencing, the recombinant plasmid pET32a-Tat22-101 was transformed into E. coli BL21(DE3) and expressed with IPTG induction. The mutant fusion protein with deleted Tat N terminal was purified by an affinity chromatography column Ni(2+)-NTA and subsequently identified by SDS-PAGE and Western blotting. The results showed that the molecular weight of the mutant protein was approximately 26.9kD. Furthermore, BALB/c mice were immunized with the mutant protein and the anti-sera were collected. ELISA results showed that the mutant protein preserved its immunogenicity, particularly it could improve the production of antibodies to other epitopes in addition to the N terminal epitope of Tat protein, which might provide some valuable information for the study of Tat functions as well as for development of potential novel HIV Tat vaccine.

Background & Objective: Bmi-1, a putative oncogene, is a member of the polycomb group genes family. It is widely expressed in many kinds of tumors. This study was to investigate the expression and significance of Bmi-1 in breast cancer., Methods: The expression of Bmi-1 protein in 58 specimens of breast cancer was detected by immunohistochemistry. The correlation of Bmi-1 expression to clinicopathologic features of breast cancer was analyzed., Results: The intensive positive rate of Bmi-1 in breast cancer was 82.8%. The intensive expression of Bmi-1 was positively correlated to clinical stage and lymph node metastasis (P < 0.05), but not to tumor size, estrogen receptor (ER), progesterone receptor (PR), c-erbB-2 and vascular endothelial growth factor (VEGF) expression (P>0.05)., Conclusions: The intensive expression of Bmi-1 in breast cancer is related to tumor progression. Bmi-1 may serve as a new molecular marker of metastasis of breast cancer.

Background & Objective: Since three-dimensional culture simulates in vivo microenvironment better than planar culture, the biological character of cells in three-dimensional culture model are more similar with that of living tissues. This study was to establish three-dimensional culture models that represent different stages of nasopharyngeal caicinogenesis, and provide information to elucidate the related molecular events., Methods: Non-tumor nasopharyngeal biopsy specimens were used to culture for normal nasopharyngeal epithelial cells. Early and late passages of normal nasopharyngeal epithelial cell line NPNE2 from nasopharyngeal biopsy specimens, immortalized nasopharyngeal epithelial cell line NP69SV40T, nasopharyngeal carcinoma (NPC) cell line SUNE-1 and its high metastatic subclone 5-8F were cultured in Matrigel to establish three-dimensional models., Results: The cells grew out of non-tumor nasopharyngeal biopsy specimens displayed the morphologic characteristics as epithelia, and could proliferate in vitro for 8-10 passages before senescence. Immunocytochemical staining of cytokeratin revealed that the cells were of epithelial origin. All of the cells, except late passages of NPNE2 cells, could proliferate in the three-dimensional culture system. NPNE2 and NP69SV40T cells mainly developed reticular structures in morphology, and formed few clones with clear and smooth edges as well as tight intercellular junctions. SUNE-1 and 5-8F cells formed clones with irregular morphology, unclear edge, and loose intercellular junctions. In addition, the clones formed by 5-8F cells also developed a lot of pseudopodia, but developed no reticular structure. Late passages of NPNE2 cells formed no clone and reticular structure in the three-dimensional culture., Conclusions: Normal nasopharyngeal epithelial cells can be successfully cultured in vitro from naspharyngeal biopsy specimens. The three-dimensional culture models, established with normal nasopharyngeal epithelial cells, immortalized nasopharyngeal epithelial cells, and NPC cells, may represent the different stages of nasopharyngeal carcinogenesis.

Background & Objective: The BARF(1) (BamHI A right frame1)gene,encoded by Epstein-Barr virus(EBV),may have oncogenic properties,which leaded to immortalization of a monkey kidney epithelial cell line and malignant transformation of human B lymphocytes and murine fibroblasts. This study was designed to evaluate effect of BARF(1) on cell transformation and tumorgenesis on human epithelia and its mechanisms., Methods: BARF(1) was amplified from B95-8 cell line by polymerase chain reaction (PCR). Eukaryotic recombinant vector pcDNA(3)-BARF(1) was constructed,and transfected into human bronchial epithelial cell line HBE,and expression of BARF(1) in the transfected cells was detected by Western blot. Growth status,proliferation rate,ability of colony formation in soft agar,and tumorigenicity of HBE cells transfected with BARF(1) were studied., Results: BARF(1) gene promoted proliferation and transformation of HBE cells. After injected with 1 x 10(7) HBE cells transfected with BARF(1),tumor nodes were observed in 2 of 6 mice at the 10th day., Conclusion: BARF(1),as a virus oncogene,may play an important role in malignant transformation of HBE cells.