Dynamic Gene Expression Mitigates Mutational Escape in Lysis-Driven Bacteria Cancer Therapy

Area of Science:

• Synthetic biology
• Microbiology
• Biotechnology

Background:

• Engineered bacteria offer precise tumor-targeted drug delivery.
• Optimizing bacterial colonization and sustained payload release remains challenging.

Purpose of the Study:

• Characterize engineered *Escherichia coli* expressing Perfringolysin O (PFO) for cancer therapy.
• Investigate dynamic strategies to overcome mutational escape and enhance therapeutic efficacy.

Main Methods:

• Experimental characterization of PFO expression and bacterial lysis.
• Genomic sequencing to identify mutations conferring resistance.
• Mathematical modeling to analyze population dynamics.
• Molecular dynamics simulations to confirm mutation effects.

Main Results:

• PFO expression induces bacterial lysis for payload release but also drives mutant selection.
• Mutations were identified that inhibit PFO-mediated lysis, leading to reduced therapeutic efficacy.
• Mathematical models revealed trade-offs between therapeutic load and mutant fraction.
• Dynamic gene expression strategies mitigate mutational escape, preserving therapeutic bacteria.

Conclusions:

• Dynamic modulation of gene expression is crucial for overcoming limitations in engineered bacteria for therapeutics.
• Repeated, short inductions of therapeutic genes can enhance durability and efficacy.
• This approach addresses mutant takeovers, improving the potential of bacteria in cancer treatment.