| Objective: Acute myelogenous leukemia is a common highly heterogeneous hematological maligant tumor, Which is characterized by abnormal clonal proliferation of myeloid hematopoietic progenitor cell, differentiation disorder, apoptosis blocked. Micro RNAs(mi RNAs) were a class of small noncoding RNAs playing their critical roles in regulating multiple biological processes such as proliferation, metastasis, apoptosis, differentiation, et al. Recent studies had demonstrated that the deregulation of mi RNAs was associated with AML initiation, progression, and had provided a new basis for mi RNAs applying to diagnosis and treatment of leukemia. This research studied the expression of mi R-125a-3p in peripheral blood samples of AML patients in different courses of disease and different subtypes, and the effect and mechanism of mi R-125a-3p.Methods:(1)Real-time fluorescent quantitative PCR was performed to detect the expression of mi R-125a-3p in peripheral blood specimens of 143 AML patients, including 64 newly diagnosed, 15 relapsed and 64 treated patients. In addition, 16 healthy persons were slected as normal controls. Moreover, 7 persons were slected randomly from newly diagnosed patients for dynamic monitoring of mi R-125a-3p levels in peripheral blood.(2) AML cell lines THP-1, HL-60, NB4, were incubated with 0.1μM retinoic acid, 10μM decitabine, 1μM arsenic trioxide, 10μM cytosine arabinoside for 24 hours, then the expression of mi R-125a-3p was detected by q RTPCR.(3)THP-1 cells were transfected with lentivirus vector of mi R-125a-3p over-expression and empty-carrier and cultivated for 48-72 hours, studiers performed the following assaies: cell surface antigens CD11 b, CD14 and the rates of cells apoptosis were measured by Flow cytometry; caspase-3, caspase-8, caspase-9 enzyme activityies were measured by spectrophotometric method, migration ability was detected by Transwell; genes of apoptosis and differentiation signal pathways were analyzed by q RT-PCR.Results:(1)Compared with normal controls, the expression levels of mi R-125a-3pwere decreased significantly in newly diagnosed and relapsed patients(P<0.05); the expression of mi R-125a-3p of patients in the treatment group were increased significantly compared with newly diagnosed patients(P<0.05), and close to the normal controls. Among different subtypes of AML(except for M3), the expression of mi R-125a-3p in newly diagnosed patients were decreased significantly compared with that in normal controls, and M0 is the lowest, M5 is next to the lowest; the expression of mi R-125a-3p of patients in the treatment group were upregulated significantly compared with that in newly diagnosed patients, even higher than that in normal controls, Furthermore, among all subtypes of AML in the treatment group, the expression of mi R-125a-3p of M2 and M4 increased more obviously. Dynamic monitoring of mi R-125a-3p levels of 7 patients showed that the expression of mi R-125a-3p maintained at a higher level in the process of the treatment; In addition, the expression of mi R-125a-3p of one patient reduced again when he relapsed after 4~5 courses of treatment.(2)The expression of mi R-125a-3p was both upregulated after decitabine and arsenic trioxide treated THP-1, HL-60, NB4, and it increased more obviously after treated with arsenic trioxide.(3)Compared with the empty vector group, the expression of cells surface CD11 b, CD14 and the cell apoptosis rate in mi R-125a-3p overexpressed cells were both increased snificantly deteced by FCM(p<0.05). The activities of caspase-3, caspase-8, caspase-9 enzyme in mi R-125a-3p overexpressed group were increased significantly compared with the empty vector group(p<0.05) detected by spectrophotometric method. Migration ability was measured by Transwell and the migration ability in mi R-125a-3p overexpressed cells were decreased significantly compared with the empty vector group(p<0.05). Furthermore, the m RNA level of differentiation related gene transcription factor ATF-2 in mi R-125a-3p overexpressed group were increased significantly compared with the empty vector group(p<0.05); the m RNA level of proapoptosis genes Bax, caspase-3, caspase-8, caspase-9 in mi R-125a-3p overexpressed group were increased significantly compared with the empty vector group(p<0.05), and the m RNA level of antiapoptotic genes Bcl-2, c-myc, NF-KB,Bcl-xl in mi R-125a-3p overexpressed group were reduced significantly compared with the empty vector group(p<0.05).Conclusions:(1)The expression of mi R-125a-3p was significantly downregulated of patients with newly diagnosed group, and rised after inductiable chemotherapy. However, the expression of mi R-125a-3p was reduced again when AML patients relapsed. To sum up, we suggested that mi R-125a-3p was expected to become a biological marker of AML for diagnosing, evaluating therapy efficacy and monitoring recurrence.(2)AML chemotherapy drugs arsenic trioxide,decitabine especially arsenic trioxide could up-regulated the expression of mi R-125a-3p.(3)In THP-1 cells, over-expression mi R-125a-3p could induce apoptosis, differentiation and inhibit cell migrating. The mechanism of inducing cell differentiation might be related to upregulation the expression of cell differentiation related transcription factors, however cell apoptosis was inducing through mitochondrial pathway; NF-KB pathways, c-myc gene might be invove in mi R-125a-3p inducing cell apoptosis. |
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