Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cell...Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cells) and ATRA-resistant APL cell line (MR2 subclone) were used as models in vitro. At various times after incubated with various concentrations of realgar, NB4 and MR2 cells were observed by cell viability , cell proliferation and cell morphology; cell cycle and the expression of Annexin V were assayed by flow cytometry. Results: Cell viability and proliferation of NB4 and MR2 cells were inhibited after the treatment, to some extent, in a dose and time dependent manner. 177 - 711g/L of realgar treated NB4 and MR2 cell presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation, apoptosis body could be found by electron microscopy as well. Sub-Gl cells and cell cycle arrest were observed by flow cytometry. The展开更多
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 expre...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.展开更多
Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia(...Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia(APL) cell lines (NB4 and MR2) and the basic mechanism of their role. Methods: NB4 and MR2 cells were respectively treated with As4S4, As2S3, As4S4 and Cyclohexamide(CHX). PCA of the cells was detected using one-stage clotting assay. TF antigen was detected by ELISA. TF and PML/RARα fusion gene mRNA by semi-quantitive RT-PCR. The PCA and TF antigen of HL-60 and K562 cells were also examined. Results: The PCA and TF antigen level in NB4 and MR2 cells were significantly higher than that in HL-60 and K562 cells. Both As4S4 and As2S3 can down-regulate the TF antigen, TF mRNA transcription and membrane PCA of NB4 and MR2 cells in vitro in a time-dependent manner. The role of As4S4 was stronger than that of As2S3. Both As4S4 and As2S3 had no effect on PML/RARαfusion gene transcription. CHX treatment completely suppressed the down-regulate effect of As4S4 on the TF mRNA expression. Conclusion: As4S4 and As2S3 may down regulate tissue factor expression and PCA of NB4 and MR2 cells. By down-regulating TF expression, As4S4 and As2S3 might be used to improve the DIC-related hemorrhage in APL patients. Elevated TF antigen level of NB4 and MR2 cells may be related to the fusion gene PML/RARα. The modulation of the TF mRNA expression in NB4 and MR2 cells by As4S4 and As2S3 might be indirect and might not involve PML/RARα fusion gene.展开更多
基金Supported by the Foundation of Chinese Medicine Administration of Shaanxi Province (1999-02, 2001-008).
文摘Objective: To further understand the possible mechanisms of arsenic sulfide (realgar) in the treatment of acute promyelocytic leukemia (APL). Methods: All-trans retinoic acid (ATRA)-susceptible APL cell line (NB4 cells) and ATRA-resistant APL cell line (MR2 subclone) were used as models in vitro. At various times after incubated with various concentrations of realgar, NB4 and MR2 cells were observed by cell viability , cell proliferation and cell morphology; cell cycle and the expression of Annexin V were assayed by flow cytometry. Results: Cell viability and proliferation of NB4 and MR2 cells were inhibited after the treatment, to some extent, in a dose and time dependent manner. 177 - 711g/L of realgar treated NB4 and MR2 cell presented morphologically some features of apoptotic cells such as intact cell membrane, chromatin condensation and nuclear fragmentation, apoptosis body could be found by electron microscopy as well. Sub-Gl cells and cell cycle arrest were observed by flow cytometry. The
基金Supported by Xi'an Foundation of Science and Technology Program(200016)
文摘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.
基金Supported by Chinese Medicine Foundation of Shaanxi Province(No.1999002)
文摘Objective: To investigate the effect of arsenic sulfide (tetra-arsenic tetra-sulfide As4S4; diarsenic trisulfide As2S3) on tissue factor (TF) expression and procoagulant activity (PCA) of acute promyelocytic leukemia(APL) cell lines (NB4 and MR2) and the basic mechanism of their role. Methods: NB4 and MR2 cells were respectively treated with As4S4, As2S3, As4S4 and Cyclohexamide(CHX). PCA of the cells was detected using one-stage clotting assay. TF antigen was detected by ELISA. TF and PML/RARα fusion gene mRNA by semi-quantitive RT-PCR. The PCA and TF antigen of HL-60 and K562 cells were also examined. Results: The PCA and TF antigen level in NB4 and MR2 cells were significantly higher than that in HL-60 and K562 cells. Both As4S4 and As2S3 can down-regulate the TF antigen, TF mRNA transcription and membrane PCA of NB4 and MR2 cells in vitro in a time-dependent manner. The role of As4S4 was stronger than that of As2S3. Both As4S4 and As2S3 had no effect on PML/RARαfusion gene transcription. CHX treatment completely suppressed the down-regulate effect of As4S4 on the TF mRNA expression. Conclusion: As4S4 and As2S3 may down regulate tissue factor expression and PCA of NB4 and MR2 cells. By down-regulating TF expression, As4S4 and As2S3 might be used to improve the DIC-related hemorrhage in APL patients. Elevated TF antigen level of NB4 and MR2 cells may be related to the fusion gene PML/RARα. The modulation of the TF mRNA expression in NB4 and MR2 cells by As4S4 and As2S3 might be indirect and might not involve PML/RARα fusion gene.
