Reprogramming a Doxycycline-Inducible Gene Switch System for Bacteria-Mediated Cancer Therapy

• Published in: Molecular imaging and biology Vol. 26; no. 1; pp. 148 - 161
• Main Authors: Ngo, Hien Thi-Thu, Nguyen, Dinh-Huy, You, Sung-Hwan, Van Nguyen, Khuynh, Kim, So-Young, Hong, Yeongjin, Min, Jung-Joon
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.02.2024; Springer Nature B.V
• Subjects: Animal models; Animals; Anticancer properties; Antitumor agents; Attenuation; Bacteria; Bacteria - genetics; Bioluminescence; Cancer therapies; Cargo; ClyA protein; Doxycycline; Doxycycline - pharmacology; Doxycycline - therapeutic use; Gene expression; Genes; Imaging; Medicine; Medicine & Public Health; Mice; Mice, Inbred C57BL; Neoplasms - drug therapy; Neoplasms - therapy; Payloads; Plasmids; Plasmids - genetics; Radiology; Research Article; Salmonella; Tumors; mediated cancer therapy; Synthetic biology; promoter; DNA recombinase; Doxycycline-inducible gene switch; Salmonella-mediated cancer therapy; Tet promoter
• ISSN: 1536-1632; 1860-2002
• DOI: 10.1007/s11307-023-01879-6

Purpose Attenuated Salmonella typhimurium is a potential biotherapeutic antitumor agent because it can colonize tumors and inhibit their growth. The present study aimed to develop a doxycycline (Doxy)-inducible gene switch system in attenuated S. typhimurium and assess its therapeutic efficacy in various tumor-bearing mice models. Procedures A Doxy-inducible gene switch system comprising two plasmids was engineered to trigger the expression of cargo genes ( Rluc8 and clyA ). Attenuated S. typhimurium carrying Rluc8 were injected intravenously into BALB/c mice bearing CT26 tumors, and bioluminescence images were captured at specified intervals post-administration of doxycycline. The tumor-suppressive effects of bacteria carrying clyA were evaluated in BALB/c mice bearing CT26 tumors and in C57BL/6 mice bearing MC38 tumors. Results Expression of the fimE gene, induced only in the presence of Doxy, triggered a unidirectional switch of the P OXB20 promoter to induce expression of the cargo genes. The switch event was maintained over a long period of bacterial culture. After intravenous injection of transformed Salmonella into mice bearing CT26 tumors, the bacteria transformed with the Doxy-inducible gene switch system for Rluc8 targeted only tumor tissues and expressed the payloads 2 days after Doxy treatment. Notably, bacteria carrying the Doxy-inducible gene switch system for clyA effectively suppressed tumor growth and prolonged survival, even after just one Doxy induction. Conclusions These results suggest that attenuated S. typhimurium carrying this novel gene switch system elicited significant therapeutic effects through a single induction triggering and were a potential biotherapeutic agent for tumor therapy.