Attenuated salmonella typhimurium mediated tumour targeting imaging based on peptides
Attenuated bacterial mediated tumor targeting diagnosis will provide a novel strategy for further cancer treatments owing to the intrinsic facultative anaerobic of bacterial and rapid proliferation in the tumor sites. In this work, we firstly investigate the in vivo behaver of the attenuated salmonella typhimurium (S. typhimurium ΔppGpp/lux) after intravenous injection. S. typhimurium exhibits rapid proliferation in the tumor site after three days of injection through the bioluminescent imaging, Luria-Bertani plate and gram-staining assay. Oppositely, S. typhimurium does not proliferate in the normal tissues and could be excreted from the body of mice. Afterwards, targeting peptides Ubiquicidine (UBI) labeled with fluorescent dyes Cy5.5 or radionuclides 125I were intravenously injected into mice with or without S. typhimurium treatments for in vivo fluorescence imaging and single photon emission computed tomography (SPECT/CT) imaging, respectively. The results show that the peptides UBI could specifically target the bacterial infected two-independent tumor models including 4T1 murrain murine breast cancer and CT26 mouse colon cancer, realizing the sensitive multimodal imaging of tumor. Such strategy (bacteria-mediated tumor targeting) may further improve the sensitivity to early diagnosis of tumors. We hope that our developed strategy could further be extended to the cancer theranostics in the future, bringing good news for cancer patients.