The Expression Of FOXO3a In Acute Myeloid Leukemia And A Preliminary Study Of Azacytidine Treatment Of AML

Objective:We evaluated the expression of FOX03a in untreated acute myeloid leukemia (AML) patients, and analyzed the correlation with the patients’prognosis. We tested the expression of FOX03a in several cell lines of leukemia and lymphoma, and figured out one cell line with the highest FOX03a gene expression; then we incubated the cell with azacytidine, observed the changes of mRNA levels, subcellular localization of FOX03a protein, cell apoptosis and cell cycle.Methods:1. Total RNA was isolated from the untreated AML patients. After it was reversed transcribed to cDNA, SYBR green-based one-step RT-qPCR was carried out to evaluate the mRNA levels of FOX03a. We got the blood routine, bone marrow cytology, chromosome, gene detection, treatment effect, and relapse data through inspecting patients’ laboratory test results and clinical data, aiming to figure out whether the mRNA levels of FOX03a have a relationship with them. Then we probed that if high FOX03a mRNA level could be considered as an adverse prognostic factor or not.2. We collected several cell lines of leukemia and lymphoma, isolated the total RNA, reversed transcribed to cDNA, evaluated the mRNA levels of FOX03a through RT-qPCR, then we figured out which kind of cell has the highest FOX03a mRNA.3. We incubated the cell with azacytidine, observed the changes of mRNA levels, subcellular localization of FOX03a protein, cell apoptosis and cell cycle. Results:1. We analyzed47primary AML patients’samples and found out that the expression of FOXO3a mRNA differs from one patient to another. Assuming the FOXO3a mRNA level of one patient with iron deficiency anemia as a value of1, the median expression of FOXO3a was0.879(range0.118-690.064); and taking the median value as a dividing line, we divided47patients into high FOXO3a mRNA group and low FOXO3a mRNA group; however, there were no significant difference between the level of FOXO3a mRNA and patients’ laboratory test results, such as peripheral white blood cells, bone marrow blast cells percentage, genetics prognosis level and FLT3and NPM1mutation after statistical analysis. In contrast, it was statistically significant that patients with high FOXO3a gene expression seemed to have a lower complete remission rate but higher recurrence rate.2. THP1was found to have a higher FOXO3a mRNA level than other cell lines through evaluating the mRNA levels of FOXO3a by RT-qPCR.3. After incubated THP1with azacytidine, the mRNA level was up-regulated, and FOXO3a protein translocated to the nucleus from the cytoplasm, and the apoptotic ratio was increased, but no evidence of cell cycle arrest was observed.Conclusions:FOXO3a gene was widely expressing in acute myeloid leukemia, while patients with higher FOXO3a mRNA usually have a lower complete remission rate but higher recurrence rate. Azacytidine could increased the apoptotic ratio of leukemia cells through up-regulating FOXO3a mRNA and promoting the translocation of FOXO3a from cytoplasm to nucleus so as to reactivate FOXO3a, making this medicine a new option for AML patients with a higher FOXO3a mRNA level.