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Published on: June 9, 2020
A novel shiga based immunotoxin against Fn-14 receptor on colorectal and lung cancer
Maryam Keshtvarz1, Ehsan Rezaei2, Jafar Amani3
1Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Department of Microbiology and Parasitology, Faculty of Medicine, The Persian Gulf Tropical and Infectious Diseases Research Center, Bushehr University of Medical Sciences, Bushehr (Iran).
Abstract:
Immunotoxins are regarded as a type of targeted therapy for killing cells by highly potent bacterial, fungal or plant toxins. Shiga like toxins (SLTs) are a group of bacterial AB5 protein toxins that inhibit host cell protein synthesis through the removal of a single adenine residue from the 28S rRNA and lead to apoptosis. Here, we described the design and usage of a Stx-based immunotoxin that can induce the selective cytotoxicity and apoptosis in Fn-14-positive cells related to the colon and lung cancer. In the present study, the Stx2a-PE15-P4A8 fusion protein was expressed efficiently in E. coli (DE3) system when driven from inclusion bodies by 8 M urea. The Stx2a-PE15-P4A8 fusion protein was expressed efficiently in E. coli (DE3) system and then purified. The purified fusion protein could specifically target Fn-14 receptor existed on colon and lung cancer cell lines and suppress these cells in a dose-dependent manner. In addition, the protein was able to nearly 50 % of apoptotic cell death and maintains about 54 % of its stability after 24 h of incubation in mouse serum at 37 °C. Compared to PE38-P4A8 construct in our previous study, these results showed that the Stx2a-PE15-P4A8 construct can be an efficient therapeutic candidate for cancer immunotherapy.
Insights
A novel Shiga-like toxin (SLT)-based immunotoxin, Stx2a-PE15-P4A8, effectively targets and induces apoptosis in colon and lung cancer cells expressing the Fn-14 receptor. This engineered toxin shows promise as a cancer immunotherapy candidate.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Immunotoxins utilize potent toxins for targeted cell killing.
- Shiga-like toxins (SLTs) are bacterial AB5 toxins that inhibit protein synthesis and induce apoptosis.
- Targeted therapies are crucial for cancer treatment.
Purpose of the Study:
- To design and evaluate a novel Stiga-like toxin (SLT)-based immunotoxin for cancer therapy.
- To assess the selective cytotoxicity and apoptosis-inducing capabilities of the Stx2a-PE15-P4A8 fusion protein against Fn-14-positive cancer cells.
- To compare the efficacy of the new construct with previous designs.
Main Methods:
- Expression and purification of the Stx2a-PE15-P4A8 fusion protein in E. coli.
- In vitro assessment of the fusion protein's cytotoxicity and apoptosis induction in colon and lung cancer cell lines.
- Evaluation of the fusion protein's stability in mouse serum.
Main Results:
- Efficient expression and purification of the Stx2a-PE15-P4A8 fusion protein.
- Specific targeting and dose-dependent suppression of Fn-14-positive colon and lung cancer cells.
- Induction of approximately 50% apoptotic cell death and 54% stability in mouse serum for 24 hours.
Conclusions:
- The Stx2a-PE15-P4A8 fusion protein demonstrates selective cytotoxicity and apoptosis induction in relevant cancer cell lines.
- The construct exhibits favorable stability in physiological conditions.
- Stx2a-PE15-P4A8 represents a promising therapeutic candidate for cancer immunotherapy.
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