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ABSTRACT: Small interfering RNAs (siRNAs) are valuable reagents for efficient gene silencing in a sequence‑specific manner via the RNA interference (RNAi) pathway. The current synthetic siRNA structure consists of symmetrical duplexes of 19‑21 base pairs (bp) with 2 nucleotide (nt) 3' overhangs. In this study, we report that an asymmetric siRNA (asiRNA) consisting of 17 bp duplex region (17 bp asiRNA) exhibited potent activity in inhibiting bcl-2 gene expression and cancer cell proliferation in vitro. Importantly, this asiRNA structure significantly reduced off‑target silencing by the sense strand. To improve the stability of the 17 bp asiRNA, we synthesized a series of chemically modified 17 bp asiRNAs. Further experiments showed that in comparison with the 17 bp asiRNA, the 17 bp asiRNA‑M2, one of the modified 17 bp asiRNAs, exhibited a comparable gene silencing activity and an improved stability in vitro. Furthermore, the 17 bp asiRNA‑M2 with a proteolipid micelle delivery system can effectively suppress the growth of H22 and BGC 803 tumors in vivo. These results suggest that the chemically modified asiRNAs may have potential as an effective therapeutic approach for cancer gene therapy in the future.
International Journal of Oncology 11/2012; · 2.40 Impact Factor
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ABSTRACT: Bifidobacterium longum (B. longum) as a delivery system for endostatin was shown to have definite antitumor effects. Moreover, it was found that the enrichment of selenium was able to enhance the immunity of mice. In order to further evaluate the safety and efficacy of B. longum carrying pBV22210-endostatin (B. longum-En) enriched with selenium (Se-B. longum-En), we determined the biochemical characteristics of Se-B. longum-En. We then investigated its effect on macrophage activity, as well as its inhibitory effect on the multiplication of pathogenic bacteria in vitro and the antitumor effects on murine hepatic (H22) tumor-bearing mice. The results showed that Se-B. longum-En exhibited similar biochemical characteristics to that of wild-type B. longum, i.e., Se-B. longum-En strongly enhanced macrophage phagocytosis in rats and inhibited the growth of pathogenic bacteria. In addition, Se-B. longum-En showed a definite inhibitory effect of tumor growth when H22 tumor-bearing mice were fed through oral or tail vein delivery. These results suggested that Se-B. longum is able to retain the advantages of wild-type B. longum and be used as a novel gene delivery system for liver cancer gene therapy.
Experimental and therapeutic medicine 01/2010; 1(1):129-135.
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Experimental and therapeutic medicine 01/2010;
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ABSTRACT: Endostatin is an endogenous inhibitor of angiogenesis and has been shown to exhibit potent inhibitory activity in certain mice tumor models. In this study, a treatment strategy of combining recombinant human endostatin (rhEndostatin) and chemotherapeutics was implemented to evaluate the therapeutic efficacy of rhEndostatin against solid tumors. The antitumor effect of rhEndostatin in combination with several chemotherapeutic drugs, e.g., 5-fluorouracil, cyclophosphamide, methotrexate, and mitomycin C, on human QGY liver tumor and mice H22 liver tumor was compared with that of rhEndostatin treatment alone. The results showed that the combination of rhEndostatin and chemotherapeutic drugs resulted in a more potent inhibition of tumor growth. The potential advantages of rhEndostatin plus tumor chemotherapy provide a basis for further clinical trials of rhEndostatin.
European journal of pharmacology 08/2009; · 2.59 Impact Factor
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ABSTRACT: Granulocyte colony-stimulating factor (GCSF) is frequently used as an adjunctive agent in tumor chemotherapy. Bifidobacterium longums (B. longum) attracted researchers' interests due to its enhancement of immunity and selective location in solid tumors. B. longum-pBV22210-endostatin (Endo) was proved to have a definite inhibitive effect on tumor growth in our previous study. In the present study, we evaluated the effects of B. longum-pBV22210-GCSF and/or B. longum-pBV22210-Endo combined with cyclophosphamide (CTX) on H22 and S180 tumor-bearing mice. Based on our previous work, the plasmid pBV22210-GCSF was constructed and transformed by electroporation into B. longum. The B. longum-pBV22210-GCSF and/or B. longum-pBV22210-Endo combined with CTX were applied to treat H22 and S180 tumor-bearing mice. A leukocyte count was carried out and the tumor inhibition rate was calculated after treatment. In our study, CTX combined with B. longum-pBV22210-GCSF significantly raised the leukocyte level of tumor-bearing mice, while combined with B. longum-pBV22210-GCSF alone or B. longum-pBV22210-Endo alone combinations with CTX inhibited tumor growth by over 65%. The results showed that B. longum-pBV22210-GCSF had an effective antagonistic effect on bone marrow inhibited by CTX and could inhibit tumor growth when it was combined with B. longum-pBV22210-Endo and CTX. Our results provide an enhanced understanding of B. longum and GCSF as well as their potential as an adjunctive approach in cancer gene therapy.
Cancer Science 08/2009; 100(10):1986-90. · 3.33 Impact Factor
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ABSTRACT: To determine the in vitro and in vivo bioactivity of recombinant human endostatin (rhEndostatin) and to analyze its pharmacokinetics and immunogenicity in rhesus monkeys and patients.
The physical chemical characteristics of rhEndostatin were detected according to Pharmacopoeia of the People's Republic of China (2005 edition, part III). Its in vitro and in vivo bioactivities were assayed via proliferation-inhibition on human umbilical vein endothelial cells and their inhibitory effect on tumor-bearing mice models. Serum concentrations of rhEndostatin in monkeys and patients were determined by an enzyme immunoassay method.
The corresponding specific in vitro activities of rhEndostatin obtained from the cell counting method, 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and lactate dehydrogenase assay, respectively, were 6.4 x 10(7), 6.7 x 10(7), and 3.8 x 10(8) U/mg, and the in vivo antitumoral potency was 4.04 x 10(7) U/mg. In rhesus monkeys, there were no gender differences in all pharmacokinetic parameters. Serum anti-rhEndostatin immunoglobulin (Ig)G antibodies were generated quickly after intravenous (iv) administration and decreased rapidly when therapy was stopped. In phase I clinical trials, linearity in the pharmacokinetics of rhEndostatin was indicated by dose-proportionate increases in the area under the curve and the maximum serum concentration. Serum rhEndostatin reached a steady-state level after 7 d of successive administration with the average concentration at a steady state of 272.44+/-91.98 ng/mL. Neither IgG nor IgM antibodies against rhEndostatin were observed in patients.
RhEndostatin exhibited a definite proliferation- inhibition effect on HUVEC, and significant antitumoral activity in mice. The immunoreactivity of rhesus monkeys to rhEndostatin is common, and rhEndostatin showed no immunogenicity in patients in this trial. The results provide a basis for further clinical trials.
Acta Pharmacologica Sinica 12/2008; 29(11):1357-69. · 1.95 Impact Factor
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ABSTRACT: Aim: To determine the in vitro and in vivo bioactivity of recombinant human endostatin (rhEndostatin) and to analyze its pharmacokinetics and immunogenicity in rhesus monkeys and patients. Methods: The physical chemical characteristics of rhEndostatin were detected according to Pharmacopoeia of the People's Republic of China (2005 edition, part III). Its in vitro and in vivo bioactivities were assayed via proliferation-inhibition on human umbilical vein endothelial cells and their inhibitory effect on tumor-bearing mice models. Serum concentrations of rhEndostatin in monkeys and patients were determined by an enzyme immunoassay method. Results: The corresponding specific in vitro activities of rhEndostatin obtained from the cell counting method, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and lactate dehydrogenase assay, respectively, were 6.4×107, 6.7×107, and 3.8×108 U/mg, and the in vivo antitumoral potency was 4.04×107 U/mg. In rhesus monkeys, there were no gender differences in all pharmacokinetic parameters. Serum anti-rhEndostatin immunoglobulin (Ig)G antibodies were generated quickly after intravenous (iv) administration and decreased rapidly when therapy was stopped. In phase I clinical trials, linearity in the pharmacokinetics of rhEndostatin was indicated by dose-proportionate increases in the area under the curve and the maximum serum concentration. Serum rhEndostatin reached a steady-state level after 7 d of successive administration with the average concentration at a steady state of 272.44±91.98 ng/mL. Neither IgG nor IgM antibodies against rhEndostatin were observed in patients. Conclusion: RhEndostatin exhibited a definite proliferation-inhibition effect on HUVEC, and significant antitumoral activity in mice. The immunoreactivity of rhesus monkeys to rhEndostatin is common, and rhEndostatin showed no immunogenicity in patients in this trial. The results provide a basis for further clinical trials.
Acta Pharmacologica Sinica 10/2008; 29(11):1357 - 1369. · 1.95 Impact Factor
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ABSTRACT: Recombinant human endostatin (rhEndostatin) has been shown to inhibit tumor growth, but the variable antitumor activity of different rhEndostatin preparations has necessitated the development of an accurate, reproducible in vivo bioassay for evaluating the rhEndostatin activity. To assess the in vivo antitumor efficacy of rhEndostatin, H22 tumor-bearing mice received three doses of rhEndostatin and the potency of rhEndostatin preparations in inhibiting tumor growth was determined by ED(50)-potency assay and validated by dose-response parallel-line assay. There was a consistent and highly reproducible linear regression relationship between rhEndostatin dosage and tumor growth inhibition rate. The ED(50) values were determined from dose-response regression lines for seven rhEndostatin preparations with high reproducibility. On the basis of the current study, the potency of rhEndostatin preparations was assigned a value of 6.09 x 10(5) U/ampoule and a 95% confidence limit of 5.96 x 10(5)-6.22 x 10(5). We consider that this procedure can be served as a potential candidate pharmacopoeial method for potency measurement of different rhEndostatin preparations.
European Journal of Pharmacology 07/2007; 564(1-3):1-6. · 2.52 Impact Factor
