Targeted Cancer Therapy Using Fusion Protein of TNFα and Tumor-Associated Fibronectin-Specific Aptide

Area of Science:

• Biotechnology
• Molecular Biology
• Oncology

Background:

• Tumor necrosis factor-alpha (TNFα) exhibits potent antitumor properties but faces limitations due to severe side effects at sub-therapeutic doses, hindering systemic delivery.
• Targeted delivery strategies are crucial to overcome the toxicity and enhance the therapeutic efficacy of TNFα in cancer treatment.

Purpose of the Study:

• To develop and evaluate a novel fusion protein linking mouse TNFα (mTNFα) with an aptide targeting the extra domain B (EDB) of fibronectin for improved tumor-specific delivery and enhanced anticancer efficacy.
• To investigate the therapeutic potential of the mTNFα-APT_EDB fusion protein in preclinical tumor models and assess its synergistic effects with chemotherapy.

Main Methods:

• A fusion protein, mTNFα-APT_EDB, was constructed by genetically linking mTNFα with an aptide specific for EDB (APT_EDB) and produced via bacterial expression in Escherichia coli.
• The binding specificity and affinity of mTNFα-APT_EDB for EDB were confirmed. Therapeutic efficacy was evaluated in mice bearing EDB-overexpressing fibrosarcomas, comparing it with unconjugated mTNFα and a non-relevant aptide conjugate.
• Combination therapy with melphalan was assessed to evaluate synergistic effects on tumor growth inhibition and drug uptake.

Main Results:

• The engineered mTNFα-APT_EDB fusion protein successfully retained its target specificity and affinity for EDB.
• In vivo studies demonstrated that mTNFα-APT_EDB significantly inhibited tumor growth in mice with EDB-overexpressing fibrosarcomas, outperforming mTNFα alone or linked to a non-specific aptide, without significant weight loss.
• Combination treatment with mTNFα-APT_EDB and melphalan resulted in a further significant increase in antitumor efficacy, suggesting a synergistic effect likely due to enhanced melphalan uptake mediated by TNFα-induced vascular permeability.

Conclusions:

• Fusion of mouse TNFα with an EDB-targeting aptide creates a promising therapeutic agent for targeted cancer treatment.
• The mTNFα-APT_EDB fusion protein offers a strategy for potent systemic delivery of TNFα, enhancing antitumor efficacy while mitigating toxicity.
• This targeted fusion protein approach, especially in combination with chemotherapy, represents a viable new therapeutic option for various cancers overexpressing EDB.