Related Experiment Video
Updated: Mar 20, 2026
Measuring Growth and Gene Expression Dynamics of Tumor-Targeted S. Typhimurium Bacteria
Published on: July 6, 2013
EGFR-targeted Chimeras of Pseudomonas ToxA released into the extracellular milieu by attenuated Salmonella
David Quintero1,2, Jamie Carrafa1, Lena Vincent1
1Department of Biology, California State University Northridge, Northridge, California, 91330-8303.
Abstract:
Tumor-targeted Salmonella VNP20009 preferentially replicate within tumor tissue and partially suppress tumor growth in murine tumor models. These Salmonella have the ability to locally induce apoptosis when they are in direct contact with cancer cells but they lack significant bystander killing, which may correlate with their overall lack of antitumor activity in human clinical studies. In order to compensate for this deficiency without enhancing overall toxicity, we engineered the bacteria to express epidermal growth factor receptor (EGFR)-targeted cytotoxic proteins that are released into the extracellular milieu. In this study, we demonstrate the ability of the Salmonella strain VNP20009 to produce three different forms of the Pseudomonas exotoxin A (ToxA) chimeric with a tumor growth factor alpha (TGFα) which results in its producing culture supernatants that are cytotoxic and induce apoptosis in EGFR positive cancer cells as measured by the tetrazolium dye reduction, and Rhodamine 123 and JC-10 mitochondrial depolarization assays. In addition, exchange of the ToxA REDLK endoplasmic reticulum retention signal for KDEL and co-expression of the ColE3 lysis protein resulted in an overall increased cytotoxicity compared to the wild type toxin. This approach has the potential to significantly enhance the antitumor activity of VNP20009 while maintaining its previously established safety profile. Biotechnol. Bioeng. 2016;113: 2698-2711. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.
Insights
Engineered Salmonella bacteria now deliver targeted cancer-killing proteins. This approach enhances antitumor activity by inducing apoptosis in EGFR-positive cancer cells while maintaining safety.
Area of Science:
- * Biomedical Engineering
- * Cancer Biology
- * Microbiology
Background:
- * Salmonella VNP20009 targets tumors but has limited bystander killing, impacting clinical efficacy.
- * Current limitations in Salmonella-based cancer therapy necessitate strategies to enhance tumor cell killing.
- * Engineering bacteria to express targeted cytotoxic proteins offers a potential solution to improve efficacy without increasing toxicity.
Purpose of the Study:
- * To engineer Salmonella VNP20009 to express epidermal growth factor receptor (EGFR)-targeted cytotoxic proteins.
- * To evaluate the cytotoxicity and apoptosis-inducing capacity of engineered Salmonella in EGFR-positive cancer cells.
- * To assess the impact of toxin modifications and co-expression of lysis proteins on overall cytotoxicity.
Main Methods:
- * Construction of Salmonella VNP20009 expressing chimeric Pseudomonas exotoxin A (ToxA) with tumor growth factor alpha (TGFα).
- * Cytotoxicity assays using tetrazolium dye reduction, Rhodamine 123, and JC-10 mitochondrial depolarization.
- * Modification of ToxA endoplasmic reticulum retention signal and co-expression of ColE3 lysis protein.
Main Results:
- * Engineered Salmonella supernatants exhibited cytotoxicity and induced apoptosis in EGFR-positive cancer cells.
- * Chimeric ToxA-TGFα proteins demonstrated dose-dependent cytotoxic effects.
- * Modifications to the ToxA toxin and co-expression of lysis protein enhanced overall bacterial cytotoxicity.
Conclusions:
- * Engineered Salmonella expressing EGFR-targeted cytotoxic proteins can effectively kill cancer cells.
- * This strategy enhances the antitumor potential of Salmonella VNP20009.
- * The approach shows promise for improving cancer therapy with a favorable safety profile.
More Related Videos
08:46A Real-time Potency Assay for Chimeric Antigen Receptor T Cells Targeting Solid and Hematological Cancer Cells
Published on: November 12, 2019
08:35Therapeutic Gene Delivery and Transfection in Human Pancreatic Cancer Cells using Epidermal Growth Factor Receptor-targeted Gelatin Nanoparticles
Published on: January 4, 2012
Related Concept Videos
02:57Targeted Cancer Therapies
There are several types of targeted therapies against...
01:28Gene Regulation in Microbial Communities: Quorum Sensing