PREreview of Engineered <em>Escherichia coli </em>Strains as Therapeutic Agents in Reactive Oxygen Species (ROS)-Mediated Glioblastoma Treatment: A Systematic Review of Mechanisms, Efficacy, and Challenges

Write a short summary of the research’s main findings and how this work has moved the field forward.

This systematic review highlights the emerging role of engineered Escherichia coli strains as therapeutic agents in glioblastoma multiforme (GBM) treatment through reactive oxygen species (ROS)-mediated mechanisms. The review synthesizes evidence that engineered bacteria can: Produce ROS directly within tumor environments, convert prodrugs into cytotoxic ROS-generating metabolites, and act as immune adjuvants by inducing immunogenic cell death.

Preclinical models demonstrate that these engineered strains can reduce tumor burden, extend survival, and synergize with immune checkpoint inhibitors. Delivery strategies, including nanogels, hydrogels, and focused ultrasound, are advancing tumor-specific targeting while minimizing systemic toxicity.

This work moves the field forward by consolidating synthetic biology, microbial engineering, and oncology into a translational framework, identifying E. coli-based therapeutics as a novel frontier for GBM treatment. It also underscores the need for biocontainment strategies, advanced delivery platforms, and regulatory clarity for clinical translation.

Major issues

• List significant concerns about the research, if there are any.

1. The review draws heavily from preclinical studies (murine and in vitro models). At the same time, promising, the lack of early-phase clinical data limits translational certainty.

2. Risks of systemic infection, septicemia, and genetic instability in kill-switch circuits are acknowledged but not thoroughly addressed with concrete solutions.

3. GBM’s diverse microenvironment may reduce the effectiveness of single-mode bacterial therapies; the review notes this but provides limited discussion on adaptive or combinatorial approaches.

4. The article briefly mentions regulatory hurdles but could expand on realistic pathways for clinical approval of live microbial therapeutics.

Minor issues

• List concerns that would improve the overall flow or clarity but are not critical to the understanding and conclusions of the research.

1. Some mechanistic explanations (e.g., ROS pathways, immune activation) are repeated across sections and could be streamlined for clarity.

2. A few key citations are heavily emphasized, while recent broader literature on bacterial cancer therapies outside GBM could enhance contextual grounding.

3. Although two tables are included, visual schematics summarizing delivery strategies or safety circuits would improve accessibility for readers.

4. Phrases like “ROS amplification” vs. “ROS production” appear interchangeably; consistent terminology would help readers follow distinctions more clearly.

Major Revision -The manuscript presents a timely and innovative synthesis on engineered E. coli for glioblastoma therapy. However, to strengthen its translational impact, the authors should address limitations in biosafety, tumor heterogeneity, and regulatory discussion. The paper is promising but requires further refinement before being considered for publication.

Competing interests

The authors declare that they have no competing interests.

Use of Artificial Intelligence (AI)

The authors declare that they used generative AI to come up with new ideas for their review.