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Published on: April 26, 2024
Photocrosslinkable, Low-Affinity Affibodies Show Improved Transport and Retention in 3D Tumor Spheroids
Bryce M Bower1, Shane D Curry1, Andrew P Goodwin1,2
1Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80303, United States.
Abstract:
The efficacy of affinity-based treatments for cancer and other diseases is often limited by poor distribution throughout the targeted tissue. Although lower-affinity antibodies will penetrate more uniformly, these often reach lower concentrations because of their rapid clearance from the tissue. To increase retention and improve distribution, we created low-affinity photocrosslinkable affibodies that can diffuse into dense tumor matrices with limited tumor barrier formation and then be photocrosslinked in place to cell receptors to increase retention. In testing with 3D tumor spheroids, the addition of a 50 nM photocrosslinkable affibody showed a similar level of accumulation at the edges of the spheroid but a higher level near the middle of the spheroid than the wild-type (non-photocrosslinkable) affibody. These results show that target affinity affects protein transport in tumor microenvironments and that covalently cross-linking the ligands to cells may improve both their transport and retention.
Insights
Researchers developed photocrosslinkable affibodies to improve cancer treatment distribution. These low-affinity proteins better penetrate tumors and can be locked in place, enhancing retention and therapeutic efficacy.
Area of Science:
- Biotechnology
- Oncology
- Protein Engineering
Background:
- Affinity-based treatments for cancer face challenges with poor drug distribution in target tissues.
- Low-affinity antibodies offer better tissue penetration but suffer from rapid clearance, limiting their concentration.
- Effective drug delivery is crucial for enhancing the efficacy of targeted therapies.
Purpose of the Study:
- To engineer low-affinity photocrosslinkable affibodies for improved retention and distribution in tumor microenvironments.
- To investigate the impact of target affinity and photocrosslinking on protein transport within dense tumor matrices.
- To enhance the therapeutic potential of affinity-based treatments by addressing distribution limitations.
Main Methods:
- Development of low-affinity photocrosslinkable affibody variants.
- Testing in 3D tumor spheroid models to assess diffusion and accumulation.
- Comparison of photocrosslinkable affibodies against wild-type (non-photocrosslinkable) affibodies.
- Evaluation of protein retention and distribution within the tumor microenvironment.
Main Results:
- Photocrosslinkable affibodies demonstrated enhanced retention within tumor spheroids compared to non-photocrosslinkable versions.
- These engineered affibodies showed improved accumulation in the central regions of the spheroids.
- The study confirmed that target affinity significantly influences protein transport in tumor microenvironments.
- Covalent cross-linking of ligands to cells improved both transport and retention.
Conclusions:
- Photocrosslinkable affibodies represent a promising strategy to overcome distribution challenges in affinity-based cancer therapies.
- Covalent cross-linking of therapeutic proteins to target cells can significantly enhance their retention and penetration in tumors.
- This approach holds potential for improving the efficacy of treatments for cancer and other diseases characterized by dense tissue barriers.
