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Updated: Aug 29, 2026
Analyzing Tumor and Tissue Distribution of Target Antigen Specific Therapeutic Antibody
Published on: May 16, 2020
Mapping tumor epitope space by direct selection of single-chain Fv antibody libraries on prostate cancer cells
Bin Liu1, Fraser Conrad, Matthew R Cooperberg
1Department of Anesthesia and Pharmaceutical Chemistry, University of California at San Francisco, San Francisco General Hospital, California, USA. Liub@anesthesia.ucsf.edu
Abstract:
The identification of tumor-specific cell surface antigens is a critical step toward the development of targeted therapeutics for cancer. The epitope space at the tumor cell surface is highly complex, composed of proteins, carbohydrates, and other membrane-associated determinants including post-translational modification products, which are difficult to probe by approaches based on gene expression. This epitope space can be efficiently mapped by complementary monoclonal antibodies. By selecting human antibody gene diversity libraries directly on the surface of prostate cancer cells, we have taken a functional approach to identifying fully human, tumor-specific monoclonal antibodies without prior knowledge of their target antigens. Selection conditions have been optimized to favor tumor-specific antibody binding and internalization. To date, we have discovered >90 monoclonal antibodies that specifically bind and enter prostate cancer cells, with little or no binding to control cells. These antibodies are able to efficiently deliver intracellular payloads when attached to nanoparticles such as liposomes. In addition, a subset of the antibodies displayed intrinsic antiproliferative activity. These tumor-specific internalizing antibodies are likely to be useful for targeted therapeutics either alone or in combination with effector molecules. The antigens they bind constitute a tumor-specific internalizing epitope space that is likely to play a significant role in cancer cell homeostasis. Targeting components of this epitope space may facilitate development of immunotherapeutic and small molecule-based strategies as well as the use of other therapeutic agents that rely upon delivery to the interior of the tumor cell.
Insights
Researchers identified over 90 fully human monoclonal antibodies that target prostate cancer cells. These antibodies bind and enter cancer cells, showing potential for targeted cancer therapeutics and drug delivery systems.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Identifying tumor-specific antigens is crucial for developing targeted cancer therapies.
- Tumor cell surface epitope complexity challenges traditional gene expression-based detection methods.
- Monoclonal antibodies offer a method to map complex tumor epitope spaces.
Purpose of the Study:
- To functionally identify fully human, tumor-specific monoclonal antibodies against prostate cancer.
- To discover antibodies that bind and internalize into prostate cancer cells without prior antigen knowledge.
- To evaluate the therapeutic potential of these antibodies for targeted drug delivery and direct anti-cancer effects.
Main Methods:
- Selection of human antibody gene diversity libraries directly on prostate cancer cell surfaces.
- Optimization of selection conditions to favor tumor-specific binding and internalization.
- Characterization of antibody binding to cancer cells versus control cells and assessment of payload delivery capabilities.
Main Results:
- Discovery of over 90 monoclonal antibodies with specific binding and internalization into prostate cancer cells.
- Minimal binding observed on control cells, indicating high tumor specificity.
- Demonstrated efficient intracellular payload delivery via antibody-conjugated nanoparticles (e.g., liposomes).
- A subset of antibodies exhibited intrinsic anti-proliferative activity against cancer cells.
Conclusions:
- Fully human, tumor-specific internalizing antibodies represent a promising avenue for targeted cancer therapeutics.
- These antibodies can be utilized alone or in combination with effector molecules for enhanced treatment efficacy.
- The identified antigens form a critical tumor-specific internalizing epitope space influencing cancer cell homeostasis, offering new therapeutic targets.
