目的：探讨靶向小鼠肝细胞再生磷酸酶-3（mouse phosphatase of regenerating liver-3， mPRL-3 ）的DNA疫苗对小鼠乳腺癌D2F2细胞体内生长的抑制作用。 方法： 构建靶向 mPRL-3 的真核表达载体pVAX1-mPRL-3，并转染至鹌鹑肌成纤维细胞QM7内，Western blotting检测mPRL-3蛋白在QM7细胞中的表达；通过重组慢病毒Lv-mPRL-3或对照载体Lv-Ctrl感染小鼠乳癌D2F2细胞，分别建立高表达 mPRL-3 的mPRL-3-D2F2细胞或对照NC-D2F2细胞，Western blotting检测小鼠乳腺癌D2F2细胞中mPRL-3蛋白的表达。BALB/c小鼠左侧乳腺脂肪垫下分别接种mPRL-3-D2F2和 NC-D2F2细胞后，通过基因枪接种pVAX1-mPRL-3疫苗（mPRL-3-D2F2/pVAX1-mPRL-3），同时设立疫苗对照组（mPRL-3-D2F2/pVAX1-Ctrl）和细胞对照组（NC-D2F2/pVAX1-mPRL-3），检测小鼠的肿瘤体积及生存期。 结果： pVAX1-mPRL-3质粒经酶切鉴定及测序验证均正确，并能在QM7细胞中表达。Western blotting检测结果显示，慢病毒感染的mPRL-3-D2F2细胞中mPRL-3蛋白过表达，而NC-D2F2细胞中不表达mPRL-3蛋白。荷瘤小鼠经pVAX1-mPRL-3 DNA疫苗免疫，其肿瘤体积明显低于对照组\[（835.3±509.8） vs (1 5430±578.4) mm3，P<0.01\]，且pVAX1-mPRL-3疫苗能显著延长荷瘤小鼠的生存期（中位生存期55.5 vs 38 d，P<005）。 结论: 基因枪接种的靶向 mPRL-3 的DNA疫苗能抑制高表达mPRL-3的小鼠乳腺癌D2F2细胞移植瘤的生长，并延长荷瘤小鼠生存期，提示其对 mPRL-3 阳性肿瘤有潜在的治疗作用。

Objective:To explore the inhibitory effect of mouse phosphatase of regenerating liver-3 (mPRL-3)-targeted DNA vaccine on the growth of mouse breast cancer D2F2 cells in vivo. Methods: The eukaryotic expression vector pVAX1-mPRL-3 targeting mPRL-3 was constructed and transfected into quail fibroblasts QM7 cells. The mPRL-3 protein expression in QM7 cells was detected by Western blotting. D2F2 mouse breast cancer cells were infected with recombinant lentivirus (Lv-mPRL-3) or control vector (Lv-Ctrl) to generate cells expressing mPRL-3 (mPRL-3-D2F2) or control cells (NC-D2F2), and the expression of mPRL-3 protein in mouse breast cancer D2F2 cells was analyzed by Western blotting. The mPRL-3-D2F2 and NC-D2F2 cells were respectively inoculated into BALB/c mice’s left mammary fad pat, then the BALB/c mice were immunized with pVAX1-mPRL-3 DNA vaccine (mPRL-3-D2F2/pVAX1-mPRL-3) by gene gun, and mPRL-3-D2F2/pVAX1-Ctrl and NC-D2F2/pVAX1-mPRL-3 were set as controls. The volume of tumor and the survival time of mice were monitored. Results: The eukaryotic expression vector pVAX1-mPRL-3 was identified by enzymatic digestion and DNA sequencing and the expression of mPRL-3 protein in QM7 cells was also confirmed. Western blotting assay results showed that the over-expression of mPRL-3 protein was detected in mPRL-3-D2F2, but not in NC-D2F2 cells. The tumor volume of the tumor-bearing mice immunized with pVAX1-mPRL-3 vaccine was significantly lower than that of the control group (\[835.3±509.8\] vs \[1543.0±578.4\] mm3, P<001\]. The pVAX1-mPRL-3 vaccination could significantly prolong the survival time of the tumor bearing mice (median survival time: 55.5 vs 38 d, P<005). Conclusion: PRL-3 -targeted vaccination mediated by gene gun can inhibit the growth of mouse breast cancer D2F2 cell xenografts expressing mPRL-3, which could be a potential therapy strategy for PRL-3 positive tumor.

国家重点基础研究发展计划（973计划）资助项目（No. 2009CB521805）