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The Influence of Cationic LiposomeMediated Endostatin Gene on Colorectal Carcinoma Liver Metastasis

Objective To investigate the influence of cationic liposomemediated endostatin gene on colorectal cancer liver metastasis. Methods Animal model for colorectal carcinoma liver metastasis were established. The plasmid expressing endostatin genelipofectAMINE were injected in vein. Results After cationic liposomemediated endostatin gene were injected in vein, the incidence of liver metastasis and mean numbers of liver tumors were decreased, survival time of animal was significantly longer. Conclusion Intravenous injection of cationic liposomemediated endostatin gene can control the development of colorectal cancer liver metastasis effectively.

Mouse endostatin gene transfected lung cancer cells inhibit proliferation of endothelial cells in vitro

Objective To observe the expression of adenovirus vector coding for mouse endostatin gene（Ad-mES） in lung cancer cells and its antiangiogenic activity in human umbilical vein endothelial cells（ECV304） in vitro.Methods Lewis lung cancer（LLC） cells were transfected with Ad-mES at different multiplicity of infection（MOI）.The expression of mES in LLC cells and supernatant after 48 hours was detected by immunohistochemical staining and Western blot respectively.The inhibitory effect of supernatant at different MOI on ECV304 non-stamulated and stimulated by basic fibroblast growth factor（bFGF） was measured by methyl thiazolyl tetrazolium（MTT） assay.Results After transfected for 48 hours，endostatin was identified in the cell plasma of infected LLC and negative result was founded in non-infected LLC.Western blot revealed band of endostatin in 20 kDa in culture supernatant of infected LLC and negative results in non-infected LLC.The inhibitory effects on ECV304 cell proliferation were ber at higher MOI，and the difference was significant between stimulated and non-stamulated cells by bFGF（Plt;0.05）.Conclusion Ad-mES can transfect and express endostatin effectively in LLC with biological activity

Serum Levels of Endostatin and Vascular Endothelial Growth Factor in Different Therapy Stages of Mouse Lewis Lung Carcinoma

Objective To investigate the serum levels of endostatin and vascular endothelial growth factor ( VEGF) at different therapy stages of mouse Lewis lung carcinoma, and elucidate the relation to the progress and prognosis of tumor. Methods Forty-four Lewis lung carcinoma-bearing C57BL/6 mice were randomly divided into 4 groups, ie. a non-therapy group, a chemotherapy group, a gene therapy group, and a combination therapy group ( chemotherapy plus gene therapy) . Eleven healthy mice were included as normal control group. Serum was collected on the 0th, 5th, 19th day after therapy for measurement of endostatin and VEGF by ELISA. The correlations were analysed between endostatin and VEGF levels in each group. Results ( 1) The serum endostatin levels had no significant difference in all groups on the 0th day,but increased significantly on the 5th day in the gene and combination therapy groups than those in other three groups ( all P lt;0. 01) . Then the endostatin level decreased on the 19th day in the gene and combination therapy groups, but still higher than those in the chemotherapy group and the normal group. ( 2 ) On the contrary, serum VEGF levels of the gene and combination therapy groups decreased significantly on the 5th day and increased little on the 19th day, which were both significant lower than those in chemotherapy group on the 5th and 19th day( all P lt; 0. 05) . There were significant diferences between the three therapy groups and the non-therapy group( all P lt;0. 05) . ( 3) Negative correlations between VEGF and endostatin levels were revealed in the gene and combination therapy groups ( r = - 0. 77 and - 0. 761 respectively) .Correlation was not found in the non-therapy and chemotherapy groups. Conclusion The serum levels of endostatin and VEGF might be used as monitoring indices of antiangiogenesis therapy.

Microencapsulation of a genetically engineered cell line secreting human endostatin

　　Objective　To microencapsulate a genetically engineered cell line which stably secrete human endostatin (hES).Methods　Endostatin gene fragment was amplified from plasmid pcDNA3-Endo by polymerase chain reaction, and inserted into mammalian eukaryotic expression vector pEGFPN1, resulting into recombinant plasmid pEGFP-N1-ES.Hek-293 cells were transfected with pEGFP-N1-ES via cationic liposome and selected by G418, and were measured by Western blot for endostatin protein expression.The hES/293 cells were further entrapped by alginate-chitosan-alginate (ACA) microcapsules, and the expression of endostatin in the supernatant of cultured hES/293 cell microcapsules was examined by western blot at different time points.Results　Recombinant plasmid pEGFP-N1 endostatin was digested by HindIII and BamHI, and resulted into 2 DNA fragments of 7 kb and 600 bp. The sequence of the 600 bp fragment was identical to human endostatin. Western blot of the supernatant of cultured hES/293 cells or hES/293 cell microcapsules detected a positive band with the relative molecular mass of 20times;103.Conclusion　The hES protein was expressed in HeK-293 transfected with pEGFP-N1-endostatin, and secreted to the culture medium,and can freely diffused outside the micro-capsule.

Gene expression of ECV304 cells after treated with endostatin detected by microarray analysis

　　Objective　To observe the altered gene expression of ECV304 cell after treated with endostatin (ES) using cDNA microarray, and to investigate its molecular mechanism.Methods　BiostarH40S gene expression DNA microarrays were used to profile changes in gene expression of ECV304 cells after treated with ES for 36 hours. To prepare the probes, mRNA from both control and treated cells were isolated and purified, and then reversely transcribed to cDNA with the incorporation of fluorescentlabeled dUTP: Cy3 and Cy5 respectively. The probes were hybridized with expressed cDNA microarray, the fluorescent signals of Cy3 and Cy5 were scanned and analyzed by a computer system.Results　ES inhibited the proliferation of ECV304 cells. The result of electrophoresis indicated that the extracted total RNA had high quality.Approximately 5.96% of all human genes examined on 4096 gene microarrays showed altered expression, with 225 downregulated genes and 19 upregulated genes.Conclusion　The expression of some genes of ECV304 cells decrease after treated with ES, which may be related to the mechanism of inhibition of neovascularization.

应用转基因技术体外培养表达内皮抑素的Brown Norway大鼠视网膜色素上皮细胞

Study on Expressions and Significances of Endostatin, bFGF and CD34 in Gallbladder Cancer

ObjectiveTo study the effects of the expressions of endostatin, basic fibroblast growth factor (bFGF) and CD34 on oncogenesis and progression of gallbladder cancer, and to explore some valuable criterias for its biotherapy. Methods The expressions of endostatin, bFGF and CD34 were studied by means of immunohistochemistry (SP) in 61 cases of gallbladder cancer and 10 cases of normal cholecystic tissue, and microvessel density (MVD) was calculated by the expression of CD34. Their relationships with clinical pathological features were also investigated. Results The expression rates of endostatin in normal cholecystic tissue and in gallbladder cancer tissue were 40.00% (4/10) and 77.05% (47/61) respectively, which had statistical difference (P＜0.05). The expression of endostatin in 61 cases of caner was relational to clinical stage and metastasis of lymph nodes (P＜0.05), while no significant correlation was detected with sex and age of patient, location of tumor, size of tumor and histologic grade (P＞0.05). The expression rates of bFGF in normal cholecystic tissue and in gallbladder cancer tissue were 20.00%（2/10） and 67.21% （41/61） respectively, which had statistical difference (P＜0.05). The expression of bFGF in 61 cases of caner was relational to clinical stage and metastasis of lymph nodes (P＜0.05), while no significant correlation was detected with sex and age of patient, location of tumor, size of tumor and histologic grade (P＞0.05). MVD in gallbladder cancer tissue and in normal cholecystic tissue was （76.66±20.15） piece/HP and (29.53±5.03) piece/HP respectively, showing significant difference (P＜0.01). In 61 cases of cancer, MVD in clinical stage Ⅲ～Ⅴ 〔(80.53±17.98) piece/HP〕 was much higher than that in stage Ⅰ+Ⅱ 〔(46.79±5.38) piece/HP〕, P＜0.01; MVD was higher in those with lymph nodes metastasis 〔(94.60±7.28) piece/HP〕 than those without metastasis 〔(58.12±9.24) piece/HP〕, P＜0.01; and MVD was (60.59±14.71) piece/HP in histologic grade G1， (83.08±15.30) piece/HP in G2， and (96.53±6.92) piece/HP in G3, the difference was significant among them （P＜0.01）. There was no significant correlation between MVD and sex and age of patient, location of tumor and size of tumor (P＞0.05). There were statistically significant correlations between expressions of endostatin and MVD （P＜0.01）, expressions of bFGF and MVD （P＜0.01）. Conclusions The result suggests that endostatin, bFGF and CD34 play roles in oncogenesis and progression of gallbladder cancer. Detection of these proteins has positive effects on diagnosis, malignant degree determination and treatment of gallbladder cancer.

Experimental Studies of Therapeutic Effect of Human Endostatin Gene Transferred into Human Liver Carcinoma Cells in Nude Mice

【Abstract】ObjectiveTo construct a recombinant eukaryotic expression vector for human endostatin in order to study the inhibitory effect of liposome-mediated endostatin gene on the growth of human liver carcinoma in nude mice. MethodsHuman endostatin cDNA including IL-2 secreting peptide was cloned into eukaryotic expression plasmid pcDNA3.0 to construct recombinant plasmid pCD-sEndo. pCD-sEndo plasmid was transferred into hepatocarcinoma cell line SMMC-7721 mediated by liposome Dosper, the expression and secretion of endostatin gene was detected by RTPCR and Western blot analysis. The suspension of SMMC-7721 cells was injected subcutaneously at the back of 32 nude mice to establish the model of human liver carcinoma. The mice were divided into 4 groups randomly, and injected with Dosper+pCD-sEndo, Dosper+pcDNA3.0, Dosper and physiological brine separately. Tumor volume was measured by stages. The mice were executed after the drug had been given for 1 week, then the microvessel density (MVD) of the tumor tissue was detected with immunohistochemical method and apoptotic index of tumor cells was measured by TUNEL-stain. ResultsThe eukaryotic expression vector pCD-sEndo was successfully constructed and was confirmed by enzyme digestion and sequence analysis. Expression of endostatin gene was detected in transfected SMMS-7721 cells by RTPCR in vitro, and endostatin protein was also detected in the supernatant of transfected SMMS-7721 cells by Western blot. In vivo study, the growth of human liver carcinoma was inhibited in the group injected with endostatin gene: the average volume of tumor in this group was significantly smaller than that in other groups （P＜0.05）; the average MVD in this group was 6.2±2.5, significantly less than that in the group injected with physiological brine (32.8±6.4), Dosper （27.8±6.4）, or Dosper+pcDNA3.0 (25.5±5.5), P＜0.05. The average apoptotic index of tumor cells in treatment group, brine group, Dosper group and Desper+pcDNA3.0 group was 24.5±7.3, 7.6±2.5, 9.5±3.0 and 11.2±3.6 respectively, it was evidently higher in the treatment group than in the latter three groups. ConclusionHuman endostatin mediated by cation liposome could decrease the microvessel number of implanted human hepatocarcinoma in nude mice. It could also accelerate apoptosis of tumor cells and inhibit growth of tumor.