Development and characterization of a potent immunoconjugate targeting the Fn14 receptor on solid tumor cells
Hong Zhou1, John W Marks, Walter N Hittelman
1Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Unit 44, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Abstract:
TNF-like weak inducer of apoptosis (TWEAK) and fibroblast growth factor (FGF)-inducible 14 (Fn14) are a TNF superfamily ligand-receptor pair involved in many cellular processes including proliferation, migration, differentiation, inflammation, and angiogenesis. The Fn14 receptor is expressed at relatively low levels in normal tissues, but it is known to be dramatically elevated in a number of tumor types, including brain and breast tumors. Thus, it seems to be an excellent candidate for therapeutic intervention. We first analyzed Fn14 expression in human tumor cell lines. Fn14 was expressed in a variety of lines including breast, brain, bladder, skin, lung, ovarian, pancreatic, colon, prostate, and cervical cancer cell lines. We then developed an immunoconjugate containing a high-affinity anti-Fn14 monoclonal antibody (ITEM-4) conjugated to recombinant gelonin (rGel), a highly cytotoxic ribosome-inactivating N-glycosidase. Both ITEM-4 and the conjugate were found to bind to cells to an equivalent extent. Confocal microscopic analysis showed that ITEM4-rGel specifically and rapidly (within 2 hours) internalized into Fn14-positive T-24 bladder cancer cells but not into Fn14-deficient mouse embryonic fibroblasts. Cytotoxicity studies against 22 different tumor cell lines showed that ITEM4-rGel was highly cytotoxic to Fn14-expressing cells and was 8- to 8 × 10(4)-fold more potent than free rGel. ITEM4-rGel was found to kill cells by inducing apoptosis with high-mobility group box 1 protein release. Finally, ITEM4-rGel immunoconjugate administration promoted long-term tumor growth suppression in nude mice bearing T-24 human bladder cancer cell xenografts. Our data support the use of an antibody-drug conjugate approach to selectively target and inhibit the growth of Fn14-expressing tumors.
Insights
This study developed an antibody-drug conjugate targeting the Fn14 receptor, showing potent and selective killing of Fn14-expressing cancer cells and suppressing tumor growth in preclinical models.
Area of Science:
- Oncology
- Molecular Biology
- Immunology
Background:
- TNF-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor (FGF)-inducible 14 (Fn14) are implicated in cellular processes.
- Fn14 is upregulated in various human tumors, presenting a therapeutic target.
Purpose of the Study:
- To develop and evaluate an antibody-drug conjugate targeting Fn14 for cancer therapy.
- To assess the efficacy and specificity of the Fn14-targeting conjugate in vitro and in vivo.
Main Methods:
- Analyzed Fn14 expression in human cancer cell lines.
- Developed an immunoconjugate (ITEM-4-rGel) of an anti-Fn14 antibody and recombinant gelonin.
- Assessed conjugate binding, internalization, cytotoxicity, and in vivo tumor growth suppression.
Main Results:
- Fn14 was expressed across diverse cancer cell lines (breast, brain, bladder, etc.).
- ITEM-4-rGel demonstrated specific internalization into Fn14-positive cells and potent cytotoxicity (8- to 8 × 10(4)-fold more than free gelonin).
- The conjugate induced apoptosis and suppressed tumor growth in a bladder cancer xenograft model.
Conclusions:
- Antibody-drug conjugates targeting Fn14 offer a promising strategy for selective cancer therapy.
- ITEM-4-rGel effectively inhibits Fn14-expressing tumor growth through targeted apoptosis induction.
