Related Experiment Video
Updated: Jun 6, 2025
Scalable Isolation and Purification of Extracellular Vesicles from Escherichia coli and Other Bacteria
Published on: October 13, 2021
Study on the biosafety and targeting efficiency of Escherichia coli outer membrane vesicles in breast tumor
Guanrong Ma1, Zhiqi Chen1, Lanxi Wang1
1State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, 400016, China.
Abstract:
To seek out the targeting of Escherichia coli outer membrane vesicles (E. coli OMVs) in breast tumor-bearing mice and their biosafety in healthy mice. Ultrafiltration in conjunction with ultracentrifugation was utilized to concentrate E. coli OMVs, and characterize them. Subcutaneous breast tumors were induced in BALB/c mice to serve as an experimental model, and the biodistribution of E. coli OMVs in both tumor-bearing and healthy mice was monitored using an in vivo fluorescence imaging system. Utilizing frozen sections, the infiltration of E. coli OMVs in tumor tissues was appraised at the 24-hour post-injection. Healthy BALB/c mice were randomly divided into control group and vesicles group. Following the intravenous injection of E. coli OMVs, monitoring encompassed variations in body weight, blood routine indices, serum levels of AST, ALT, and BUN, organ indices (heart, liver, spleen, lung, and kidney), along with tissue histopathology over a 14-day period. The spherical E. coli OMVs had a diameter of (155.8 ± 3.1) nm and exhibited the expression of outer membrane proteins OmpA and OmpC. Upon assessment, it was evident that the E. coli OMVs persisted in the tumor tissues even 24 h post-injection. An evident decrease in the body weight of the vesicles group, distinct from the control group, was observed on the second day after injection (P < 0.001); in contrast, no considerable differences were noted at subsequent time points (P > 0.05). Following the injection, the vesicles group displayed notable reductions in WBC and PLT as relative to the control group (P < 0.0001) on the initial day, however, there were no noteworthy distinctions as opposed to the control group for other hematological indices; No notable variances in hematological indices between the two groups were observed on the seventh and fourteenth day (P > 0.05). Over the 14 days, no substantial differences were observed in the serum levels of BUN, AST, ALT, and organ indices within the vesicles group as opposed to the control group (P > 0.05). Furthermore, there were no obvious abnormal changes in tissue morphology. 0.5 mg/kg of E. coli OMVs can safely and effectively target 4T1 breast tumor in mice.
Insights
Escherichia coli outer membrane vesicles (E. coli OMVs) effectively target breast tumors in mice. These OMVs demonstrated biosafety in healthy mice, with no significant adverse effects observed over 14 days.
Area of Science:
- Biotechnology and Nanomedicine
- Oncology and Cancer Research
- Microbiology and Immunology
Background:
- Outer membrane vesicles (OMVs) from Escherichia coli are being explored for targeted drug delivery.
- Understanding the biodistribution and safety of OMVs is crucial for their potential therapeutic applications in cancer.
Purpose of the Study:
- To evaluate the targeting efficiency of E. coli OMVs in a murine model of breast cancer.
- To assess the biosafety profile of E. coli OMVs in healthy mice.
Main Methods:
- E. coli OMVs were concentrated and characterized using ultrafiltration and ultracentrifugation.
- Biodistribution was monitored in tumor-bearing and healthy mice using in vivo fluorescence imaging.
- Biosafety was assessed through body weight, hematological indices, serum biochemistry, organ indices, and histopathology over 14 days.
Main Results:
- E. coli OMVs demonstrated significant accumulation in breast tumor tissues 24 hours post-injection.
- A transient decrease in body weight and white blood cell/platelet counts was observed in the OMV group, with no lasting effects.
- No substantial differences in serum markers, organ indices, or tissue morphology were noted between OMV-treated and control groups.
Conclusions:
- E. coli OMVs exhibit effective targeting of 4T1 breast tumors in mice.
- A dosage of 0.5 mg/kg E. coli OMVs is considered safe for administration in mice, with no significant long-term toxicity observed.
