Abstract 5621: NCG-X mouse: A novel animal model to evaluate preclinical studies of humanized erythroid reconstitution without irradiation

Abstract

Abstract Hematopoietic stem cell (HSC) transplantation is an adoptive immunotherapy for treating malignant hematopoietic cancers and autoimmune disorders. Preclinical studies of such novel therapies require animal models that enable and sustain human erythrocyte reconstitution. Existing mouse models typically require irradiation to remove mouse HSCs from the bone marrow prior to human immune system reconstitution. Irradiation adversely affects the health of the animal by promoting necrosis and apoptosis of gastrointestinal, neural and muscle tissues, which can lead to wasting, infection, and even death. An irradiation-free mouse model for human erythroid reconstitution is in urgent need. KIT proto-oncogene receptor tyrosine kinase, also known as c-KIT, is an important cell surface marker expressed in both mouse and human HSCs, multipotent progenitors (MPP), and common myeloid progenitors (CMP). KIT signaling plays a key role in cell survival, proliferation, and differentiation. Alterned forms of this protein have been shown to be associated with some types of cancer. Point mutation of Val831Met is known to cause macrocytic anemia. We speculate that mice with this mutation experience spontaneous anemia and inhibited HSC function, which would support human erythroid reconstitution without irradiation. NCG-X mouse was generated based on this hypothesis, building upon the severe immunodeficient NCG generated by GemPharmatech years ago. This new strain of mice are deficient of T/B/NK cells with functional inhibition of HSCs. Here, we report that NCG-X supports human HSC transplantation without radiation, enabling complete avoidance of adverse effects on animal health. When compared with irradiated NCG mice, NCG-X mice are able to not only rebuild the human immune system, but also enable human erythroid cells to reconstruct the bone marrow for a prolonged period of time after engraftment: 16 and 30 weeks post-engraftment have been assayed. Though reduced red blood cells and hemoglobin have been observed, 30 weeks post-engraftment enables consistent support from the start to the finish of the preclinical phase. In conclusion, NCG-X provides an improved and preclinical relevant mouse model for therapeutic development of leukemia, thalassemia, other types of blood diseases and autoimmune diseases. Citation Format: Tingting Gu, Cunxiang Ju, Hongyan Sun, Xiang Gao, MingKun Zhang, Weiwei Yu, Mengting Wang, Shuai Li, Shuai Li, Huiyi Wang, Jing Zhao. NCG-X mouse: A novel animal model to evaluate preclinical studies of humanized erythroid reconstitution without irradiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5621.