Immunological evaluation of virulence-deficient Listeria monocytogenes strains in C57BL/6 mice

Living therapeutics: Precision diagnosis and therapy with engineered bacteria

Bacteria-based therapy has emerged as a promising strategy for cancer treatment, offering the potential for targeted tumor delivery, immune activation, and modulation of the tumor microenvironment. However, the unpredictable behavior, safety concerns, and limited efficacy of wild-type bacteria pose significant challenges to their clinical translation. Recent advancements in synthetic biology and chemical engineering have enabled the development of precisely engineered bacterial platforms with enhanced controllability, targeted delivery, and reduced toxicity. This review summarize the current progress of engineered bacteria in cancer therapy. We first introduce the theoretical underpinnings and key advantages of bacterial therapies in cancer. Subsequently, we delve into the applications of genetic engineering and chemical modification techniques to enhance their therapeutic potential. Finally, we address critical challenges and future prospects, with a focus on improving safety and efficacy. This review aims to stimulate further research and provide valuable insights into the development of engineered bacterial therapies for precision oncology.

Systematic identification of a panel of strong promoter regions from Listeria monocytogenes for fine-tuning gene expression

BACKGROUND

Attenuated Listeria monocytogenes (Lm) has been widely used as a vaccine vector in the prevention and treatment of pathogen infection and tumor diseases. In addition, previous studies have proved that the attenuated Lm can protect zebrafish from Vibrio infections, indicating that the attenuated Lm has a good application prospect in the field of aquatic vaccines. However, the limitation mainly lies in the lack of a set of well-characterized natural promoters for the expression of target antigens in attenuated Lm.

RESULTS

In our study, candidate strong promoters were identified through RNA-seq analysis, and characterized in Lm through enhanced green fluorescent protein (EGFP). Nine native promoters that showed stronger activities than that of the known strong promoter P36 under two tested temperatures (28 and 37 °C) were selected from the set, and P29 with the highest activity was 24-fold greater than P36. Furthermore, we demonstrated that P29 could initiate EGFP expression in ZF4 cells and zebrafish embryos.

CONCLUSIONS

This well-characterized promoter library can be used to fine-tune the expression of different proteins in Lm. The availability of a well-characterized promoter toolbox of Lm is essential for the analysis of yield increase for biotechnology applications.