Xu Y-F, Zhu L-P, Hu B, Fu G-F, Zhang H-Y, Wang J-J, Xu G-X
Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, 22 Hankou Road, Nanjing University, Nanjing 210093, China.
Cancer Gene Ther. 2007 Feb;14(2):151-7. doi: 10.1038/sj.cgt.7701003. Epub 2006 Oct 27.
To utilize Bifidobacterium longum (B. longum) as a safe and stable delivery system for endostatin in cancer gene therapy, we constructed pBV22210 vector combining a chloramphenicol-resistance gene (Cm(r)) from pBCSK(+) plasmid, a cryptic plasmid pMB1 from B. longum strain with pBV222. Endostatin was cloned directly downstream of an N terminal His6-tag sequence in the pBV22210, so that the endostatin protein expressed in B. longum could be purified with Ni-binding resin. The results indicated that the plasmid electroporated into B. longum was maintained stably in the absence of selective antibiotics and did not significantly affect biological characteristics of B. longum. In addition, the plasmid in B. longum showed a strong inhibitory effect on the growth of mouse solid liver tumor in vivo. These results suggested that this new plasmid may be a stable vector in B. longum for transporting anti-cancer genes in cancer gene therapy.
为了将长双歧杆菌（B. longum）用作癌症基因治疗中内皮抑素的安全稳定递送系统，我们构建了pBV22210载体，该载体将来自pBCSK(+)质粒的氯霉素抗性基因（Cm(r)）与来自长双歧杆菌菌株的隐蔽质粒pMB1和pBV222结合在一起。内皮抑素被直接克隆到pBV22210中N端His6标签序列的下游，这样在长双歧杆菌中表达的内皮抑素蛋白就可以用镍结合树脂进行纯化。结果表明，导入长双歧杆菌的质粒在没有选择性抗生素的情况下能稳定维持，并且对长双歧杆菌的生物学特性没有显著影响。此外，长双歧杆菌中的质粒在体内对小鼠实体肝肿瘤的生长显示出强烈的抑制作用。这些结果表明，这种新质粒可能是长双歧杆菌中用于癌症基因治疗中转运抗癌基因的稳定载体。
