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Archive > Volume 20 Issue 5 > 2013,20(5):529-534. DOI:10.3872/j.issn.1007-385X.2013.05.004 Prev Next
Basic Research
Preparation of streptavidin-tagged interleukin-7 fusion protein and its therapeutic effect with intravascal instillation on mouse superficial bladder cancer
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Abstract:
Objective : To prepare streptavidin-tagged interleukin-7 (SA-IL-7) fusion protein and to value its therapeutic effect on mouse superficial bladder cancer. Methods: Recombinant pET24a-SA-IL-7 plasmid was constructed and then SA-IL-7 fusion protein was prepared. The binding of SA-IL-7 to biotinylated bladder cancer MB49 cells was examined by flow cytometry and the bioactivity of SA-IL-7 fusion protein was examined by thymocyte proliferation assay. The mouse superficial bladder cancer model was used to evaluate the therapeutic effect of intravesical instillation of SA-IL-7. Mice were monitored for survival and the tumor-infiltrated CD8+T cells were examined by immunohistochemistry assay. Results: SA-IL-7 fusion protein efficiently anchored on the biotinylated MB49 cell surface, with a binding ratio of (96.6±13)%; SA-IL-7 promoted the proliferation of thymocytes. The SA-IL-7 fusion protein anchored on biotinylated bladder mucosal surface for more than 7 d. Whereas, IL-7 was no longer detected in the first day in the unbiotinylation group. After being attacked by bladder cancer MB49 cells for 80 d, 90% mice in the IL-7 group, while 60% mice survived without tumors in the SA-IL-7 group (P<0.05). Moreover, tumor-infiltrated CD8+ T cells in the SA-IL-7 group was significantly higher than those in the control group (P<0.01). Importantly, 11 out of 15 SA-IL-7-cured mice resisted to a second intravesical MB49 cell challenge, whereas only 1 of 15 control mice survived the challenge (P<0.01). Conclusion: Intravesical instillation of SA-IL-7 fusion protein can induce anticancer immunity, which may represent a promising immunotherapy for superficial bladder cancer.
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Project Supported:
Project supported by the National 863 Plan Foundation of China (No. 2006AA02Z4C4), and the Natural Science Foundation of Zhejiang Province (No. R2080407)
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