| Background and PurposeLeukemia(Leukemial) is a hematopoietic stem cells from the body due to gene regulation, and thus the formation of malignant clone disease, malignant clone cells proliferated these cumulative, so that normal hematopoiesis is suppressed, extensive infiltration of the liver, spleen, lymph nodes and other organs. Enhanced self-renewing leukemic cells, uncontrolled proliferation, differentiation, and apoptosis obstacles blocked, so stuck in different stages of cell development. Clinical manifestations of anemia(usually positive cells are pigmented anemia), bleeding(thrombocytopenia), infection(neutropenia) and invasive(usually involved spleen, lymph nodes) and other signs. AL can be broadly divided into acute lymphoblastic leukemia(Acute Lymphoblastic Leukemia1) and acute myeloid leukemia(Acute myeloid Leukemia1) according to the main malignant proliferation of cell lines. According to the proliferation of leukemia cells in the immune phenotype, ALL can be divided into B-cell, T-cell and T / B hybrid. Where T-cell ALL(T-ALL) is the uncontrolled proliferation of T cells, a large number of T cell differentiation disorders malignant clonal proliferation, accumulation, and thus a large number of T cell infiltration in tissues characterized by hematologic malignancies, accounting for 15% ALL of- 25%, unlike the B-cell ALL, it has a unique clinical manifestations, cytogenetics, immunology and molecular biology, and so on. T-ALL patients withpoor prognosis compared to other types of leukemia, especially some of the children, to countless families suffering and economic losses. With the development of medicine, a variety of chemotherapy drugs combined with chemotherapy and high-dose chemotherapy in clinical applications, making the prognosis of patients with T-ALL has greatly improved, but the effects are still some poor T-ALL patients, even high-dose chemotherapy can not achieve complete remission, so that, T-ALL treatment is still the focus of the current difficulties and treatment of leukemia.Demethylating drug decitabine(Decitabine, DAC) is a specific inhibitor of DNA methylation, the current research focus more concentrated in DAC play demethylation in leukemia, so as to achieve treatment goals, the latest study found abroad, DAC can also participate in a variety of signaling pathways activated processes, such as JAK-STAT, indicating a possible role of its promotion of apoptosis in other ways, but on the DAC proapoptotic study abroad rarely.TAL1(T cell acute lymphoblastic leukemia1) gene is located on chromosome 1p32, and the faculties of the development of blood cells to form hematopoietic stem cells play a crucial role. TAL1 gene is acute T lymphoblastic leukemia(T-ALL) patients with the most common chromosomal rearrangements target, has long been considered to be generated by the initiator of T-cell leukemia. Although initially TAL1 gene in chromosome translocations occurred T-ALL patients found, but then studies have shown that it served an integral role in normal blood cell differentiation. Animal studies indicate that, TAL1 development starting in mouse embryos 8.5 days, followed by expression in epithelial tissue and nerve tissue in the erythroid lineage cells and macrophages also expressed; the researchers knocked out after TAL1 gene, the mice were 9.5 days in the death of the late experiments further show that TAL1 gene deletion mice, embryonic stem cells, blood cells and primitive hematopoietic permanent organization can develop.. Than 60% of T-ALL patients, TAL1 expression level is elevated, suggesting the occurrence of cancer and it plays an important role in the progress. However, what causes the high expression of TAL1 has yet to be understood. This study, the role of different concentrations of DAC in Jurkat leukemia cell lines, Jurkat cells were observed on the proliferation, apoptosis and influence on gene expression of TAL1. For the treatment of T-ALL DAC provideslaboratory evidence.Materials and Methods1.WST-1 cell growth rate measured: using a final concentration of 0.5,1,5,10μmol / L of DAC effect Jurkat cells 24 h, 48,72 h, to determine the role of decitabine in a suitable concentration of cells with time in. 2. morphological changes: the 0μmol / L and 5μmol / L DAC role in Jurkat cells 48 h, inverted fluorescence microscope. Jurkat cells were detected in the experimental group to detect and control group 3. TAL1 m RNA expression analysis by Real-time PCR test methods. 4. Flow cytometry apoptosis: 5μmol / L DAC role in Jurkat cells after 48 h, with Annexin V-FITC / PI double staining by flow cytometry apoptosis.Results1.WST-1 showed that: different concentrations of DAC on the proliferation of Jurkat cells were significantly inhibited. DAC final concentration 0.5,1,5,10μmol / L, acting on Jurkat cells 24 h, on Jurkat cell proliferation was inhibited, the inhibition rate was(13.8 ± 1.15)%, respectively,(25.8 ± 0.93)%,(41.6 ± 2.01)%,(49.5 ± 0.48)%; each concentration group and the control group(1.70 ± 0.25)% compared with the differences were statistically significant(P <0.05); different concentrations of two groups, the difference was statistical significance(P <0.05). DAC5μmol / L effect on Jurkat cells 24,48,72 h, on Jurkat cells significantly inhibited the growth inhibition rate was(41.6 ± 2.01)%,(55.8 ± 1.22)% and(59.6 ± 2.13)%, between the two groups two compare, 24 h and 48 h group difference was statistically significant(P <0.05); 48 h and 72 h group, the difference was not statistically significant(P>0.05). Thus calculated decitabine treatment of Jurkat cells half inhibitory concentration(IC50 values) close 5μmol / L and therefore choose their subsequent trial for the experimental group.2. morphological changes: WST-1 test results according to DAC Best action time and IC50 values to 0μmol / L and 5μmol / L DAC effect on Jurkat cells 48 h, fluorescence was observed under an inverted microscope, 5μmol / L in the experimental group compared 0μmol / L in the control group was significantly deformed nuclei, concentrated, kidney-shaped nucleus and petal-like changes, indicating DAC induced apoptosis in Jurkat cells.3.Detected in the experimental group Jurkat cell line expression levels were significantly lower TAL1 m RNA(0.375 ± 0.0156) analyzed by Real-time RT-PCR test method compared with the control group(1.038 ± 0.049), the difference was statistically significant(P = 0.002; t = 12.92).4.Flow cytometry apoptosis: Annexin V and PI double staining flow cytometry results showed that apoptosis, 5μmol / L DAC, acting on Jurkat cells after 48 h, its apoptotic rate was(63.5 ± respectively 1.6)%, higher than the control(7.4 ± 0.8)%(P <0.05), the difference was statistically significant.ConclusionDecitabine can inhibit proliferation and induce apoptosis in Jurkat cells, significantly down TAL1 m RNA expression. |
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