Construction of Invasive Engineered Strain Targeted for Cancer Therapy Using Transposon

Transposons are a kind of genome sequence jumping freely on the genome sequence and are also valuable tools for gene transfer modification and insertional mutagenesis of microorganisms. However, there has been no report about applications of transposons in gram-negative bacteria E. coli Nissle1917. In this study, we constructed pR6K translocation vector that contains the inv gene from Yersinia pseudotuberculosis and the hly locus from Listeria monocytogenes . Introduction of the inv and hly genes into the chromosomes of E. coli Nissle1917 confers it the ability to invade mammalian cells. Through in vitro experiments, we found that engineered bacteria have good activity for a wide variety of tumor cells, such as B16 and HCT-116. Besides, we transferred Azurin protein expressing vector into the engineered bacteria acting on the B16 cells, greatly improving treatment efficacy. This work has opened up a new way for further application with E. coli Nissle1917 as a carrier of DNA vaccine or gene therapy.