Effect of realgar on telomerase activity and hTERT-mRNA expression in NB4 cells

Objective: To evaluate whether realgar could down-regulate human telomerase reverse transcriptase (hTERT) gene expression and telomerase activity in acute promyelocytic leukemia cell line-NB4 cells. Methods: The expression of hTERT-mRNA was analyzed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). Flow cytometry using PI staining was applied to analyze the cell cycle and apoptosis. Results: Treatment of NB4 cells with 155, 300, 600 μg/L realgar reduced telomerase activity significantly accompanying with decrease of hTERT-mRNA and increasing cell apoptosis. G2/M phase arrest appeared when treated with realgar in 300, 600 μg/L. Conclusion: It is suggested that telomerase activity of NB4 cells can be specifically inhibited by realgar through the down-regulation of hTERT gene expression. G2/M phase arrest and apoptosis by realgar in NB4 cells might be related to the reduction of telomerase activity and hTERT-mRNA expression.

Analyses of therapeutic effects using rludarabine and cytarabine on acute myeloid leukemia at different stages during treatment

Objective: To evaluate the therapeutic effect of the fludarabine and cytarabine (FA) regimen on acute myeloid leukemia (AML) at different phases during treatment. Methods: A total of 185 patients with AML were divided into 4 groups based on the outcome of previous treatments. Patients in Group 1 had no remission after the first course of induction chemotherapy (n = 55). Patients in Group 2 had no remission after no less than two courses of induction chemotherapy (n = 41). Patients in Group 3 had early relapse (n = 40). Patients in Group 4 had late relapse (n = 49). Patients in groups 2, 3 and 4 had refractory AML or AML with relapse. We assessed the efficacy and toxicity of FA combination chemotherapy in each of these 4 groups. Results: The complete remission (CR) rates of Groups 1, 2, 3 and 4 were 74.5% (41/55), 45.9% (19/41), 17.5% (7/40) and 38.8% (19/49), respectively. The CR rate was higher in Group 1 than in the other 3 groups (34.6%, 45/130) (P = 0.000). A significant correlation was found between CR rate and the number of chemotherapeutic courses (P = 0.023). The main adverse reactions included bone marrow suppression and secondary infection. Conclusion: FA regimen is a good choice for patients with AML, especially those who have failed to achieve CR after the first course of induction chemotherapy.

Detection of human herpesvirus 8 DNA in acute leukemia patients

Objective To determine the prevalence of human herpesvirus 8 (HHV-8) DNA in acute leukemia (AL) patients. Methods The presence of HHV-8 DNA sequences in peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) from 50 AL patients was examined using polymerase chain reaction (PCR). Nine human hematopoietic cell lines and PBMC from 30 normal donors were also included. Results HHV-8 DNA sequences were detected in one case of acute myelogenous leukemia (AML). The specimens from the bone marrow aspirate, peripheral blood and serum of this patient were all positive. None of the normal donors and human hematopoietic cell lines showed evidence of HHV-8 DNA. Conclusion The results suggest that the prevalence of HHV-8 is low in AL in China.