[Effect of Negative Regulation of LncRNA XIST to MiR-196b on the Biological Behavior of Acute Myeloid Leukemia Cells KG1a].

OBJECTIVE: To investigate the effect and molecular mechanism of lncRNA X-inactive specific transcript (XIST) on the proliferation and apoptosis of acute myeloid leukemia cells KG1a. METHODS: Forty-one patients with acute myeloid leukemia from January 2017 to May 2019 treated in Beijing Aerospace Center Hospital were collected, as well as 20 patients who conformed to the international standard of iron deficiency anemia as control group. KG1a cells were divided into pcDNA group, pcDNA-XIST group, pcDNA-XIST+miR-NC group, and pcDNA-XIST+miR-196b group. Real-time fluorescence quantitative PCR was used to detect the expressions of XIST and miR-196b, CCK-8 was used to detect cell activity, flow cytometry was used to detect cell cycle and apoptosis, Western blot method was used to detect the protein expressions of cleaved-caspase3, pro-caspase3, Bax, and Bcl-2, and dual luciferase report experiment was used to detect the targeting relationship between XIST and miR-196b. RESULTS: The expression level of lncRNA XIST in bone marrow cells in the AML group was significantly lower than that in the iron deficiency anemia group (P<0.001). Compared with pcDNA group, the expression level of lncRNA XIST, proportion of cells in G0/G1 phase, apoptosis rate, and the expression levels of cleaved-caspase3 and Bax in the pcDNA-XIST group of KG1a cells were significantly increased (all P<0.001), while the expression level of miR-196b, cell viability, the proportion of S-phase cells, and the expression levels of pro-caspase3 and Bcl-2 were significantly decreased (all P<0.001). Compared with pcDNA-XIST group, the cell activity, proportion of S-phase cells, and the expression levels of pro-caspase3 and Bcl-2 in the pcDNA-XIST+miR-196b group were significantly increased (all P<0.001), while the proportion of cells in the G0/G1 phase, apoptosis rate, and the expression levels of cleaved-caspase3 and Bax decreased (all P<0.001). CONCLUSION: Overexpression of lncRNA XIST can inhibit the proliferation of acute myeloid leukemia cells KG1a and promote apoptosis by down-regulating the expression of miR-196b.

[Changes of T-cell clonality after induction-cultivation of peripheral T lymphocytes in adoptive immunotherapy for leukemias].

This study was purposed to analyze the changes of T-cell clonality after induction of peripheral T lymphocytes by autogenous DC and cytokines in the preparation of adoptive immunotherapy for leukemias. The bone marrow and peripheral blood from 21 leukemia patients at remission stage after treatment and subjected to adoptive immunotherapy were collected. Their DCs and T-cells were stimulated with cytokines and then were mixed to activate T-cells. T-cell receptor beta variable region (TCRBV) families were amplified by RT-PCR, and genescan method and sequencing of the PCR products were used to observe the clonality changes of T-cells before and after the induction and cultivation of T-cells. The flow cytometry was used to identify CD3(+), CD4(+), CD8(+), CD3(+)CD56(+) and CD4(+)CD25str(+)FOXP3(+) cells to disclose the ratio change of cytotoxic T lymphocytes (CTL), helper T-cells, regulatory T-cells and NK T-cells before and after induction and cultivation of T-cells. The results showed that in the 21 patients, most of the 24 TCRBV families presented as oligoclonal distribution on genescan, several families were not expressed, and only a few families remained polyclonal. TCRBV24 was found to be oligoclonal in all of the 21 patients. DNA sequence analysis of TCRBV24 revealed a common motif of VAG in CDR3 in 3 cases and a common motif of GGG in CDR3 in 2 cases. In patient 5, both TCRBV 24 and TCRBV8 contained the same motif of GGG in CDR3. The identical motif in these patients may suggest that these T-cells recognize the same antigen. The peripheral lymphocytes demonstrated recovery of clonal profile on genescan from oligoclonal profile and absence of several families before the induction and cultivation to typical polyclonal profile in all TCRBV families after the induction by DC and cytokines for 13 days. After the induction and cultivation, the number of lymphocytes increased to 3.38 +/- 1.20 times. CD3(+), CD4(+), CD8(+), CD3(+)CD56(+) and CD4(+)CD25str(+)FOX P3(+) cells were 71.1 +/- 11.8%, 26.7 +/- 11.4%, 35.7 +/- 12.9%, 3.1 +/- 1.6% and 0.12 +/- 0.1% respectively before the induction and cultivation, and changed to 95.4 +/- 3.2% (p < 0.01), 27.0 +/- 13.1% (p > 0.01), 55.5 +/- 13.8% (p < 0.01), 9.8 +/- 6.1% (p < 0.01) and 0.22 +/- 0.18% (p < 0.01) respectively after the induction and cultivation. It is concluded that the major action of this induction and cultivation method on T-lymphocytes in vitro is the promotion of CTL and NK T-cell proliferation. In leukemic patients at the remission stage, the TCRBV profile is characterized by the oligoclonal proliferation of T-lymphocytes. Several proliferated clones may have the same motif in CDR3, suggesting the recognition of the same antigen by these lymphocyte clones. Cytokine induction and co-culture with autogenous DCs can stimulate the T-lymphocytes to recover their immunocompetence as manifested by the polyclonal profile and the proliferation of CTL and NK-T cells.