Engineering of bacteria for the visualization of targeted delivery of a cytolytic anticancer agent.
A number of recent reports have demonstrated that attenuated Salmonella typhimurium are capable of targeting both primary and metastatic tumors. The use of bacteria as a vehicle for the delivery of anticancer drugs requires a mechanism that precisely regulates and visualizes gene expression to ensure the appropriate timing and location of drug production. To integrate these functions into bacteria, we used a repressor-regulated tetracycline efflux system, in which the expression of a therapeutic gene and an imaging reporter gene were controlled by divergent promoters (tetAP and tetRP) in response to extracellular tetracycline. Attenuated S. typhimurium was transformed with the expression plasmids encoding cytolysin A, a therapeutic gene, and renilla luciferase variant 8, an imaging reporter gene, and administered intravenously to tumor-bearing mice. The engineered Salmonella successfully localized to tumor tissue and gene expression was dependent on the concentration of inducer, indicating the feasibility of peripheral control of bacterial gene expression. The bioluminescence signal permitted the localization of gene expression from the bacteria. The engineered bacteria significantly suppressed both primary and metastatic tumors and prolonged survival in mice. Therefore, engineered bacteria that carry a therapeutic and an imaging reporter gene for targeted anticancer therapy can be designed as a theranostic agent.
1] Laboratory of In Vivo Molecular Imaging, Chonnam National University Hwasun Hospital, Hwasun, Republic of Korea [2] Department of Nuclear Medicine, Haikou Hospital Affiliated to Xiangya School of Medicine, Central South University, China.
Sheng-Nan
SN
Jiang
Seung-Hwan
SH
Park
Hee Jung
HJ
Lee
Jin Hai
JH
Zheng
Hyung-Seok
HS
Kim
Hee-Seung
HS
Bom
Yeongjin
Y
Hong
Michael
M
Szardenings
Myung Geun
MG
Shin
Sun-Chang
SC
Kim
Vasilis
V
Ntziachristos
Hyon E
HE
Choy
Jung-Joon
JJ
Min
D000818:Animals; D045744:Cell Line, Tumor; D004318:Doxycycline / Q000008:administration & dosage / Q000494:pharmacology; D017930:Genes, Reporter; D005818:Genetic Engineering; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008163:Luminescent Measurements; D008175:Lung Neoplasms / Q000628:therapy*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009362:Neoplasm Metastasis / Q000628:therapy*; D054353:Perforin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*
D054353:Perforin; D004318:Doxycycline