Immunotherapy: TARGETING EWING SARCOMA (ES), OSTEOSARCOMA (OS) AND NEUROBLASTOMA (NB) WITH ANTI-MCAM CHIMERIC ANTIGEN RECEPTOR (CAR) MODIFIED NATURAL KILLER (NK) CELLS
Author Type(s)
Faculty
Document Type
Abstract
Publication Date
2022
Journal Title
Cytotherapy
Department
Pediatrics
Abstract
Background & Aim: Background Pediatric patients with metastatic ES, OS and NB have a dismal average 5-year survival (<25%). Novel therapeutic approaches are desperately needed (Nayyar 2019). The melanoma cell adhesion molecule (MCAM) is highly expressed in pediatric solid tumors and constitutes a novel target for immunotherapy (Orentas, 2012). We previously demonstrated the anti-tumor efficacy of anti-CD20 CAR NK cells against Burkitt lymphoma in a humanized xenograft mouse model (Chu 2015). NKTR-255 is an investigational IL-15Rα-dependent, polymer-conjugated, recombinant human IL-15 agonist that retains the full spectrum of IL-15 biology, including expansion of NK cells (Miyazaki 2021, Robinson 2021). Aims Here we developed an anti-MCAM CAR NK cell and investigated its in vitro and in vivo efficacy alone or in combination with NKTR- 255 (provided by Nektar Therapeutics) in promoting NK cell cytotoxicity against ES, OS and NB. Methods, Results & Conclusion: Method Peripheral blood mononuclear cells (PBMCs) were expanded into NK cells ex vivo using K562- mbIL21-41BBL feeder cells in the presence of IL-2. Anti-MCAM CAR NK cells were generated by non-viral electroporation of anti-MCAM CAR mRNA into expanded NK cells. Results We found a significantly increased cytotoxicity of anti-MCAM CAR NK cells compared to mock NK cells against ES, OS and NB cells (Fig 1A). The enhanced cytotoxicity of the anti-MCAM CAR NK cell is due to specific targeting of MCAM, because CRISPR/Cas9 mediated MCAM knockout diminished the sensitivity of tumor cells to anti-MCAM CAR NK compared to mock NK cells. Furthermore, the combination of NKTR-255 significantly increased the cytotoxic activity of anti-MCAM CAR NK cells (Fig 1B). In in vivo studies, we found that anti-MCAM CAR NK cells significantly decreased tumor growth (Fig 1C) and prolonged animal survival compared to vehicle and mock NK cells in a NB xenograft mouse model, but not in an ES patient derived xenograft (PDX) model. Furthermore, using an orthotopic xenograft mouse model of ES, we found that anti- MCAM CAR NK therapy significantly reduced lung metastasis (42% vs 14%, p<0.05) and prolonged animal survival (0% vs 50%, p<0.05), and NKTR-255 further enhanced these anti-tumor effects of anti- (Figure Presented) MCAM CAR NK cells (0% lung metastasis and 71% survival) (Fig 1D). Conclusion Our findings demonstrated efficacy of anti-MCAM CAR NK cells alone and/or in combination with NKTR-255 against malignant pediatric solid tumors in vitro and in vivo. Supported in part by U54 CA232561.
Recommended Citation
Luo, W., Gardenswartz, A., Chu, Y., Rosenblum, J., Ayello, J., Overwijk, W., Cripe, T., Cassady, K., Lee, D. A., & Cairo, M. S. (2022). Immunotherapy: TARGETING EWING SARCOMA (ES), OSTEOSARCOMA (OS) AND NEUROBLASTOMA (NB) WITH ANTI-MCAM CHIMERIC ANTIGEN RECEPTOR (CAR) MODIFIED NATURAL KILLER (NK) CELLS. Cytotherapy, 24 (5), S109. https://doi.org/10.1016/S1465-3249(22)00301-2