Engineering of Bacteria for the Visualization of Targeted Delivery of a Cytolytic Anticancer Agent

Abstract

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.

Salmonella-Mediated Cancer Therapy: Roles and Potential

“…Jiang et al inserted Renilla luciferase and ClyA genes on both sides of this promoter to simultaneously visualize the bacteria and deliver the toxin gene [30].…”

“…The most common way to image bacteria in small animal models is labeling them with luminenescence gene operon derived from a luminescent bacterial strain [6,7,30]. The bacterial luciferase (lux) operon encodes five gene clusters, lux C, D, A, B, and E. Lux A and B express bacterial luciferase enzyme, while lux C, D, and E control fatty aldehyde enzyme complex production, which synthesizes the substrates.…”

“…Overcoming these obstacles is important to move BMCT closer to clinical application in the future. [7,10,71,72] pTet Tetracylin [30] RecA Radiation [12] Quorum sensing Bacterial density [72,73] Hypoxia-inducing promoters Low oxygen condition [11,20,72,74,75] …”

Optimizing the restored chemotactic behavior of anticancer agent Salmonella enterica serovar Typhimurium VNP20009

“…Several strains of S. Typhimurium have been constructed for the purpose of tumor targeting and chemotherapy delivery, most mentionable being: A1 (Zhao et al, 2005)/A1-R Hiroshima et al, 2013;Hoffman, 2016;Hiroshima et al, 2014;Yano et al, 2014;Murakami et al, 2016;Kawaguchi et al, 2016), BRD509/BRD509E (Yoon et al, 2014;al-Ramadi et al, 2009), χ4550 (Saltzman et al, 1996), CRC2631 (Eisenstark et al, 2007), ΔppGpp (Jiang et al, 2013;Kim et al, 2015;Nguyen et al, 2010), LH340 (Zhang et al, 2007;VanCott et al, 1998;Jia et al, 2012), LVR01 (Grille et al, 2014), MvP728 (Manuel et al, 2011;Xu et al, 2014;Xiong et al, 2010), RE88 (Xiang et al, 2005;Lee et al, 2006;Qian et al, 2011), SA186 (Chirullo et al, 2015), SB824 (Roider et al, 2011), SL3261 (Lin et al, 2012;Ye et al, 2013), SL7207 (Jarosz et al, 2013;Li et al, 2013;Shi et al, 2016;Berger et al, 2013), YB1 (Li et al, 2017;Yu et al, 2015), and VNP20009 . VNP20009 was created by Low et al ) from strain 14028s through selection for hyperinvasion by chemical/UV mutagenesis.…”

Pseudomonas aeruginosa mannose-sensitive hemagglutinin inhibits proliferation and invasion via the PTEN/AKT pathway in HeLa cells

“…Three methods are commonly used to treat cervical cancer: surgery, chemotherapy and radiation therapy. However, recent research has demonstrated that engineered bacteria can be used to treat cancer [4], and the development of a new treatment method for cervical cancer is feasible.…”