Abstract 3770: CAR-T cell harboring a camelid single domain antibody as a targeting agent to kill tumors expressing VEGFR2
Bibliographic record
Abstract
Abstract Modulation of the immune system is showing tremendous promise in the treatment of malignancies. In addition to checkpoint inhibitors that re-activate T cells present in the tumor microenvironment, exogenously transduced chimeric antigen receptor (CAR) T cells are providing excellent responses in clinical trials for the treatment of leukemias. In this study, we describe CAR-T cells that target VEGFR2-expressing tumors. Angiogenesis is the process of new blood vessel formation and is essential for a tumor to grow beyond a certain size. Tumors secrete the pro-angiogenic factor vascular endothelial growth factor (VEGF), which acts upon local endothelial cells by binding to vascular endothelial growth factor receptors (VEGFR). As VEGFR2 is also expressed by a variety of tumors, we investigated the utility of anti-VEGFR2 CAR-T cells as a method to treat VEGFR2-expressing tumors. Camelid antibodies are small (14 kD) single chain antibodies. To generate a camelid antibody targeting the extracellular domain of VEGFR2, a llama was immunized with recombinant VEGFR2/Fc. A phage display library was generated and screened to identify an antibody with high binding affinity to VEGFR2. The selected antibody was expressed in the E. coli. BL21 (DE3) pT7 system. The purified antibody was characterized by SEC, LC-MS peptide mapping and ELISA. CAR-T cells were engineered to express the camelid anti-VEGFR2 antibody in combination with the CD28 and 4-1BB costimulatory molecules and the CD3 zeta chain. Tumor cells were screened for expression of VEGFR2, and the HL-60 acute promyelocytic leukemia, ZR-75-30 breast ductal carcinoma and NCI-H23 non-small cell lung adenocarcinoma were identified. Co-incubation of anti-VEGFR2 CAR-T cells with the VEGFR-2-expressing cell lines resulted in dose-dependent target cell toxicity as measured by LDH release. In addition, T cell activity was confirmed, as high levels of IL-2 and IFN-γ were detected in the cell culture media. These results suggest that anti-VEGFR2 CAR-T may be useful in directly targeting VEGFR2-expressing tumors. We previously showed the utility of camelid antibodies in CAR-T constructs as anti-CEACAM6 CAR-T cells show both in vitro and in vitro efficacy against the pancreatic tumor Bx-PC3. The use of the a camelid V21 antibody to target VEGFR2-expressing tumors provides hope that camelid single domain antibodies can be developed for CAR-T therapies. Citation Format: Heman Chao, Baomin Tian, Marni Uger, Wah Wong. CAR-T cell harboring a camelid single domain antibody as a targeting agent to kill tumors expressing VEGFR2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3770. doi:10.1158/1538-7445.AM2017-3770
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".