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Updated: Apr 25, 2026
Examining BCL-2 Family Function with Large Unilamellar Vesicles
Published on: October 5, 2012
Improving the therapeutic potential of endostatin by fusing it with the BAX BH3 death domain
R M Chura-Chambi1, M H Bellini1, J F Jacysyn2
1Centro de Biotecnologia, Instituto de Pesquisas Energéticas e Nucleares - IPEN - CNEN/SP, São Paulo, Brazil.
Abstract:
Endostatin (ES) inhibits angiogenesis, reducing tumor growth in animal models. However, it has low therapeutic effect in human clinical trials. BAX is a member of the BCL-2 family of proteins; its proapoptotic (BH3) domain interacts with other members of the family in the cytoplasm, to induce apoptosis. Here, we fused the BAX BH3 domain with murine ES, to enhance ES potency. Endothelial cells specifically internalize the fusion protein ES-BAX. The presence of the BAX domain enhances endothelial cell death by apoptosis by 1.8-fold and diminishes microvessel outgrowth in the rat aortic ring assay by 6.5-fold. Daily injections of 15 μg of ES-BAX/g in tumor-bearing mice reduce tumor weight by 86.9% as compared with ES-treated animals. Co-immunoprecipitation assays confirmed that ES-BAX interacts with members of the BCL-2 family. Also, ES interacts with BCL-2, BCL-XL, and BAK in endothelial cell lysates, suggesting a potential new mechanism for the apoptosis induction by ES. The superiority of the ES-BAX antiangiogenic effect indicates that this fusion protein could be a promising therapeutic alternative to treat cancer.
Insights
A novel fusion protein, endostatin-BAX (ES-BAX), enhances anti-angiogenic therapy by promoting cancer cell apoptosis. This improved therapeutic agent significantly reduces tumor growth in preclinical models.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Endostatin (ES) is an angiogenesis inhibitor with limited clinical efficacy.
- The BAX protein's BH3 domain induces apoptosis by interacting with the BCL-2 family.
- Enhancing ES potency is crucial for effective anti-cancer therapy.
Purpose of the Study:
- To create a fusion protein, ES-BAX, by combining endostatin with the BAX BH3 domain.
- To evaluate the enhanced anti-angiogenic and anti-tumor effects of ES-BAX.
- To investigate the mechanism of apoptosis induction by ES-BAX.
Main Methods:
- Fusion protein construction (ES-BAX).
- In vitro assays: endothelial cell apoptosis and rat aortic ring assay.
- In vivo studies: tumor growth inhibition in tumor-bearing mice.
- Co-immunoprecipitation to analyze protein interactions.
Main Results:
- ES-BAX significantly increased endothelial cell apoptosis (1.8-fold) and reduced microvessel outgrowth (6.5-fold).
- Daily ES-BAX injections reduced tumor weight by 86.9% compared to ES alone.
- Co-immunoprecipitation confirmed ES-BAX interaction with BCL-2 family members, suggesting a novel apoptosis pathway.
Conclusions:
- The fusion protein ES-BAX demonstrates superior anti-angiogenic and anti-tumor activity compared to endostatin alone.
- ES-BAX induces apoptosis in endothelial cells, potentially through interactions with the BCL-2 family.
- ES-BAX represents a promising therapeutic candidate for cancer treatment.
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