Despite the success of immune checkpoint blockade (ICB) therapies in recent years, they are limited to a minority of patients due to innate (primary) resistance. Combination therapy that uses dual ICB, anti-PD-1 and anti-CTLA4 has shown promising results in advanced melanoma as compared to either monotherapy. As the number of combination therapies is ever increasing, there is a need for an ICB assay that can accurately predict the efficacy of these therapies in the preclinical and clinical settings in a timely manner. Murine-derived/patient-derived organotypic tumor spheroids (MDOTS/PDOTS) developed by Jenkins et al in AIM 3D cell culture devices address this need (see reference (1)). MDOTS/PDOTS isolated from mouse and patient tumors retain the autologous immune cells and matrixes which are critical for the ICB response. The preserved tumor microenvironment ensures that the tumor-immune and cell-matrix interactions are not compromised in this ex vivo assay. MDOTS/PDOTS not only recapitulate the in vivo immune response (as shown below), but also yield the results within a week which can help accelerate the drug discovery process.

Key References

1. RNA sensing induced by chromosome missegregation augments anti-tumor immunity. Sasaki, N., Homme, M., Murayama, T., Osaki, T., Tenma, T., An, T., … & Kitajima, S. (2025). Molecular cell, 85(4), 770-786
2. Radiation-guided nanoparticles enhance the efficacy of PARP inhibitors in primary and metastatic BRCA1-deficient tumors via immunotherapy. Khoury, R., Longobardi, G., Barnatan, T. T., Venkert, D., Alvarado, A. G., Yona, A., … & Satchi-Fainaro, R. (2025). Journal of Controlled Release, 383, 113812
3. Immune targeting of triple-negative breast cancer through a clinically actionalbe STING agonist-CART cell platform. Zhang, Y., Li, Z., Ritter, J., Brea, E. J., Mahadevan, N. R., Dillon, D. A., … & Barbie, T. U. (2025). Cell Reports Medicine
4. Targeting TBK1 to overcome resistance to cancer immunotherapy. Sun, Y., Revach, O. Y., Anderson, S., Kessler, E. A., Wolfe, C. H., Jenney, A., … & Jenkins, R. W. (2023). Nature, 615(7950), 158-167
5. MPS1 inhibition primes immunogenicity of KRAS-LKB1 mutant lung cancer. Kitajima, S., Tani, T., Springer, B. F., Campisi, M., Osaki, T., Haratani, K., … & Barbie, D. A. (2022). 40(10), 1128-1144
6. WEE1 inhibition induces anti-tumor immunity by activating ERV and the dsRNA pathway. Guo, E., Xiao, R., Wu, Y., Lu, F., Liu, C., Yang, B., … & Chen, G. (2021). Journal of Experimental Medicine, 219(1), e20210789
7. Dynamic single-cell RNA sequencing identifies immunotherapy persister cells following PD-1 blockade. Sehgal, K., Portell, A., Ivanova, E. V., Lizotte, P. H., Mahadevan, N. R., Greene, J. R., … & Barbie, D. A. (2021). The Journal of clinical investigation, 131(2)
8. CXCR1 and CXCR2 Chemokine Receptor Agonists Produced by Tumors Induce Neutrophil Extracellular Traps that Interfere with Immune Cytotoxicity. Teijeira, Á., Garasa, S., Gato, M., Alfaro, C., Migueliz, I., Cirella, A., … & Melero, I. (2020). Immunity, 52(5), 856-871
9. PD-L1 engagement on T cells promotes self-tolerance and suppression of neighboring macrophages and effector T cells in cancer. Diskin, B., Adam, S., Cassini, M. F., Sanchez, G., Liria, M., Aykut, B., … & Miller, G. (2020). Nature immunology, 21(4), 442-454
10. Immuno-PET identifies the myeloid compartment as a key contributor to the outcome of the antitumor response under PD-1 blockade. Rashidian, M., LaFleur, M. W., Verschoor, V. L., Dongre, A., Zhang, Y., Nguyen, T. H., … & Ploegh, H. L. (2019). Proceedings of the National Academy of Sciences, 116(34), 16971-16980

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