The Role Of MiR-29c/b2 On The Extramedullary Infiltration Of Murine AML

BackgroundExtramedullary infiltration of AML is a common clinical manifestation.Through the autopsy on the death of leukemia patients,more than 50% of the patients with AML extramedullary infiltration of digestive system and urinary system,while respiratory,nervous,genital system also involved.Meanwhile,it is regarded that the survival and relapse of AML are related to the extramedullary infiltration of AML.When bone marrow relapse(BMR)has not yet appeared,extra-medullary relapse(EMR)is usually ignored.The EMR happens in 5%-20% of AML-CR patients,which can be founded in almost all the body systems such as nerves,skin,liver,spleen,digestive tract.EMR from the complete remission is on average 9 months,and 50-90 days after EMR the BMR is usually detected.mi RNA participates in the process of multiple solid tumors metastasis,but its role in extramedullary infiltration of AML is still unknown.And the extramedullary infiltration of leukemia is closely related to the relapse and survival period of patients,so the relationship between mi RNA and the extramedullary infiltration of leukemia and the molecular mechanism is worth exploring.ObjectiveBy observing the occurrence of AML in mi RNA-29c/b2 knockout mice,the regulation of mi RNA-29c/b2 on the extramedullary infiltration of AML was proved.Thus,the important role and significance of mi RNA in the process of AML extramedullary infiltration are further validated.Method1.Observation on the regulation of biological function of AML cells by mi RNA-29c/b2The si RNA was used to reduce the expression of mi R-29c/b2 in leukemic cell strains.The adhesion and metastasis of leukemic cells in the knockout group were observed by the adhesion experiment between leukemic cells and parenchyma cells,so as to clarify the regulation of mi RNA-29c/b2 on the migration and adhesion ability of leukemic cells.2.Observation on the regulation of mouse spontaneous-AML-extramedullary infiltration by mi R-29c/b2The mi RNA-29c/b2 knockout C57 mice is provided by Prof.Fei using of CRISPR/Cas9 system.the Friend retrovirus secreted by the FBL-3 cell line is inoculated in mice in order to transform the normal hematopoietic stem cell to AML cells.By observing the changes in peripheral blood and the proportion of leukemia cells in peripheral blood after the inoculation,the survival period and the general view of the external organs are observed.Survival curve is made,and the infiltration of mice from different groups is compared to clarify the regulation of mouse spontaneous-AML-extramedullary infiltration by mi R-29c/b2.3.Observation on the regulation of mouse AML-extramedullary infiltration by the knockout of mi RNA-29c/b2 in extramedullary organThe FBL-3 leukemia cells expressing GFP after the lentivirus transfection are inoculated in the mi RNA-29c/b2 knockout C57 mice,causing the mouse secondary AML.By comparing the survival rate and the proportion of GFP positive AML cells in peripheral blood and the extramedullary organs of mice from two groups,the effects of microenvironment changes on leukemia extramedullary infiltration during the secondary leukemia while tumor cell genome unchanged is to identify the regulation of mouse AML-extramedullary infiltration by the knockout of mi RNA-29c/b2 in extramedullary organ.Results1.The adhesion and migration abilities of AML cells are regulated by the mi R-29c/b2 which is detected by the fluorescence microscope.2.Results of the mouse spontaneous leukemia model shows that the metastasis of KO mice is less than WT group.The results also show that the deficiency of mi R-29c/b2 is related to the extramedullary infiltration of AML and significantly affects the survival of leukemia mice.3.Results of the mouse secondary leukemia model shows that the mi R-29c/b2 knockout in the extramedullary organs makes no contribute to the extramedullary infiltration of AML.Conclusion1.mi RNA-29c/b2 regulates the adhesion and migration abilities of AML cells.2.The extramedullary infiltration of AML in mi RNA-29c/b2 knockout mice is less than the WT mice which is provided by the mouse spontaneous leukemia model.3.The absence of mi RNA-29c/b2 in the extramedullary organs does not affect the extramedullary infiltration of AML which is provided by the mouse secondary leukemia model.