The Expression Of Livin In Acute Leukemia Cells And Its Clinical Significance

PartⅠThe expression of livin in acute leukemia cells and its clinical significance【Objective】To investigate the expression of livin in acute leukemia (AL) bone marrow cells, and analyze the relationship between the expression of livin and the clinical significance.【Methods】RT-PCR was applied to monitor livin gene expression in 50 patiens with newly diagnosed AL. It was analysised by clinical samples that the expression of livin variants correlated with complete remission of newly diagnosed AL.【Results】The expression of livin mRNA in AL bone marrow cells was significantly higher than that in the normal bone marrow cells (P<0.01). The levels of livin gene expression positively correlated with increased poor CR for newly diagnosed AL patients, especially for acute lymphocytic leukemia (ALL).【Conclusion】Livin may serve as a novel tumor marker verdict poor clinical prognosis for ALL patients. Livin can be a new gene target for anti-leukemia therapy.PartⅡthe study of siRNA-induced down-regulation of livin expression in K562 cell lines【Objective】To observe the targeted inhibition effects of livin gene expression in K562 cells by siRNA interference.【Methods】Livin siRNA duplexes were purchased from the Ambion Company. K562 cells were electroporated by Nucleofector, and incubated. Livin mRNA was detected by RT-PCR, and protein was detected by western blot. Control was Non-electroporated cells. The enhanced green fluorescent protein (EGFP) plasmid was used as positive control and the transfection efficiency was detected by flow cytometry. Cell apoptosis was measured by AnnexinⅤ-FITC assay. The sensitiveness toward etoposide, which is agents that induce the mitochondrial pathway was detected by MTT. Caspase-3 activation was detected by Caspase kit. 【Results】The transfection efficiency was about 50%. The synthesized siRNAs inhibited livin gene expression at both mRNA and protein levels. Transient inhibition of Livin alone led only to a limited increase in apoptosis, whereas it strongly sensitized the cells toward the action of proapoptotic agents, such as etoposide. K562 cell apoptosis was from 9.63±0.08% in control group to 12.03±0.13% and 27.41±0.31% at 24 h and 48 h after transfection respectively. Caspase-3 activation was raised from 100% to 145%.The IC50 was decreased from 10μmol/L to 5μmol/L.【Conclusion】Inhibition of livin gene expression by siRNAs can inhibit anti-apoptosis of livin gene, which provides the new method for anti-leukemia study.