2020 Fiscal Year Research-status Report

Immune evasion of AML cells from FceRI+ cells through MEIS1 activity

Research Project

Project/Area Number	19K07678
Research Institution	National Cancer Center Japan
Principal Investigator	アーノクズィネ国立研究開発法人国立がん研究センター, 先端医療開発センター, 特任研究員 (70725621)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	Acute Myeloid Leukemia / Meis1 / Immune evasion
Outline of Annual Research Achievements	In our experimental setting, generation of H9M1 leukemic cells is achieved through retroviral integration of HOXA9 and MEIS1 genes into hematopoietic stem cells from bone marrow. However, this obligatory experimental condition can potentially lead to artifactual results due to random gene integration. Therefore, we undertook to reproduce our previous results with new H9M1 clones of cells, followed by MEIS1 deletion (H9/DeltaM1 cells) and transfection with SYK (H9/DeltaM1-SYK cells) as performed previously. After completion of the 3 stable cell lines (H9M1, H9/DeltaM1 and H9/DeltaM1-SYK cells), cells were injected into C57Bl/6 mice and RAG2 KO mice. Leukemia onset with these new cell lines is currently under verification. We are also currently establishing the minimum number of H9M1 cells required to induce leukemia in C57Bl/6 mice for further injection of H9/DeltaM1-SYK cells into Mcpt8-DTR+ transgenic mice treated with Diphtheria Toxin (basophil-depletion), in order to confirm the ability of these cells to induce leukemia in basophil-depleted mice but not C57Bl/6 mice. In vitro, proliferation of H9/DeltaM1-SYK cells was inhibited when co-incubated with splenic cells from C57Bl/6 mice, while H9M1 expansion was poorly affected, confirming our previous results.
Current Status of Research Progress	Current Status of Research Progress 4: Progress in research has been delayed. Reason In January 2020, I changed institute from JFCR to National Cancer Center East Hospital (Kashiwa), starting a new project on cancer immunotherapy. I am still a visiting scientist at JFCR and I pursue experiments related to the above project, but at a lower pace since these projects have to be achieved in different institutes.
Strategy for Future Research Activity	We are planning to reproduce our previous results with the new clones of cells (H9M1, H9/DeltaM1 and H9/DeltaM1-SYK cells) that we recently generated, in order to demonstrate that previous data were not artifactual as an outcome of random gene integration. This step will strengthen and validate the identification of the transcription factor MEIS1 as a master regulator for immune escape of leukemic cells, which will be necessary for publication. Reproducibility of our results includes the ability of H9/DeltaM1-SYK cells to induce leukemia in immune deficient mice such as RAG2 KO and Mcpt8-DTR+ transgenic mice, but not in immune competent mice such as C57Bl/6 mice.
Causes of Carryover	In January 2020, I changed institute from JFCR to National Cancer Center East Hospital (Kashiwa), starting a new project on cancer immunotherapy. I am still a visiting scientist at JFCR and I pursue experiments related to the above project, but at a lower pace since these projects have to be achieved in different institutes.