Expression And Clinical Significance Of Exosome Derived MiR-181b-5p In Childhood Acute Lymphoblastic Leukemia

Objective: As a medium of intercellular communication,exosomes play an important role in the development and progression of hematological cancer.Micro-RNAs(miRNAs),as the contents of exosomes,play important role in the biological function of exosomes.The expression characteristics of exosome derived miR-181 family in different diseases are various,and there are currently no in-depth studies on the expression characteristics of exosome derived miR-181b-5p in acute lymphoblastic leukemia(ALL).This study aimed to investigate the differences in the expression levels of exosome derived miR-181b-5p in different disease stages of children with ALL and its relationship with clinical characteristics.Methods: The enrolled children were divided into primary diagnosis group,relapse group,remission group,rehabilitation control group by inductive collation of clinical data.Bone marrow plasma samples were collected from 86 children with ALL enrolled in the study,exosomes were extracted from bone marrow plasma using an exosome extraction kit,and the extracted exosomes were identified by the following three methods: morphology by transmission electron microscopy,internal diameter by nanoparticle tracking analysis(NTA),and identification of exosome marker proteins by Western blot(WB),RNA was extracted from exosomes by the Trizol method,and the levels of miR-181b-5p in the plasma exosomes of each affected child were determined by real-time fluorescence quantitative PCR(RT-q PCR).Statistical analysis was performed using Graphpad Prism8 software,and counting data were expressed as percentages and processed using the chi square test and Fisher’s exact probability.The measurement data were expressed as median(range),and analyzed by rank sum test,differences were statistically significant at p< 0.05.Results: Of the 86 enrolled children,42 were newly diagnosed children with ALL,12 were children with relapse,14 were regularly followed up in remission,and 18 were rehabilitation controls.Exosomes were successfully extracted from bone marrow plasma using an exosome extraction kit,and exosome particles were observed under a transmission electron microscope to have a double layered membrane structure and to be saucer like,WB showed that exosomal marker proteins TSG101 and CD81 were stably expressed in exosomes derived from the plasma of children in different groups,NTA showed that the size distribution diameter of exosomes was in the range of30-150 nm.By statistical analysis,we found that exosomal miR-181b-5p expression levels in children with ALL were significantly lower in the initial diagnosis group and the relapse group than in the remission and control groups(p < 0.05),the plasma exosomal miR-181b-5p expression levels in children with T-ALL in the newly diagnosed group were higher than those in children with B-ALL(p < 0.05),the plasma exosomal miR-181b-5p expression in male children was higher than that in female children in the newly diagnosed group(p < 0.01).Conclusions: Exosome derived miR-181b-5p showed dynamic changes in expression levels at different disease stages in children with ALL and could be used as a marker miRNA for monitoring disease states,exosomes can deliver information in the tumor microenvironment as a potential carrier for biomolecule targeted therapy.