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Tumor-targeted Salmonella as a novel anticancer vector
J M Pawelek1, K B Low, D Bermudes
1Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA. sodi@biomed.med.yale.edu
Cancer Research
|October 23, 1997
Summary
Genetically engineered Salmonella bacteria can target and replicate within tumors, offering a novel gene delivery vector for cancer therapy. Attenuated strains show reduced pathogenicity while retaining tumor-targeting capabilities, enhancing treatment efficacy.
Area of Science:
- Microbiology
- Oncology
- Gene Therapy
Background:
- Limited investigation exists on using bacteria as gene delivery vectors.
- Genetically engineered Salmonella possess properties suitable for a delivery vector, including tumor targeting and replication.
Purpose of the Study:
- To investigate the potential of genetically engineered Salmonella as a gene delivery vector for cancer therapy.
- To evaluate the efficacy of attenuated Salmonella strains in targeting tumors and delivering therapeutic genes.
Main Methods:
- Utilized attenuated, hyperinvasive auxotrophic Salmonella mutants for tumor targeting in melanoma-bearing mice.
- Constructed a plasmid expressing herpes simplex virus thymidine kinase (HSV TK) in Salmonella.
- Administered HSV TK-expressing Salmonella and ganciclovir to evaluate tumor suppression and survival rates.
Main Results:
- Attenuated Salmonella selectively replicated within tumors, achieving high tumor:liver ratios (250:1 to 9000:1).
- Salmonella inoculation suppressed tumor growth and doubled survival time in mice.
- HSV TK-expressing Salmonella combined with ganciclovir demonstrated dose-dependent tumor suppression and prolonged survival.
Conclusions:
- Attenuated Salmonella are effective gene delivery vectors with inherent antitumor activity.
- These bacteria can be engineered to deliver therapeutic proteins, like HSV TK, for enhanced cancer treatment.
- Genetically modified Salmonella offer a promising platform for in vivo cancer therapy.