ARSENICTRIOXIDE REGULATES CHRONIC LYMPHOCYTIC LEUKEMIA PROLIFERATION BY TARGETING XPO1/SURVIVIN PATHWAY SIGNALLING
(Abstract release date: 05/19/16)
EHA Library. Su Y. 06/09/16; 132568; E1019
Prof. Yan Su
Contributions
Contributions
Abstract
Abstract: E1019
Type: Eposter Presentation
Background
Chronic lymphocytic leukaemia(CLL) is characterized by the progressive accumulation of clonal mature B-cells in the blood, bone marrow, and lymphoid organs and by a highly variable clinical course. Elevated expression of exportin 1 (XPO1/CRM1) has been reported in CLL and correlated with a poor prognosis and resistance to therapy. Inhibition of XPO1 can result in CLL cell death in vitro and increased survival in a CLL mouse model. The efficacy of XPO1 inhibitor for the treatment of diffuse malignant peritoneal mesothelioma may rely on interference with the function of survivin. Our previous work showed that arsenic trioxide(As2O3) induced apoptosis in a CLL cell linetogether with up-regulation of p53 and down-regulation of survivin. Taken together, these findings raise the question of whetherAs2O3 might inhibit CLL by inducing apoptosis via the suppression of XPO1/survivin pathway signalling.
Aims
We sought to investigate whether XPO1/survivin pathway signalling might be involved in the anti-CLL effect induced by As2O3.
Methods
The expression of XPO1 in the MEC1 cell line and primary peripheral blood cells from CLL patients was assessed by qPCR and compared with the expression in purified peripheral normal B-cells. XPO1 siRNA was used to knockdown XPO1 expression in MEC1 cells. XPO1 plasmid transfection was used to overexpress XPO1. Thesurvival and apoptosis rates of MEC1 cells induced by As2O3were determinedby 7-AAD,Annexin V-PI and caspase3/7 analysis. The expression of various genes associated with apoptosis, including Bax, PUMA, survivin, BCL-2, BCL-x and XIAP, were assessed by real-time PCR.XPO1 normal and XPO1 knockdown MEC1 cells were inoculated intravenously intoNOD/scid/γcnull(NSG) mice to establish a human leukaemia xenograft model. We assessed tumour characteristics, including organ infiltration, apoptosis, andexpression of survivin, ki67 and XPO1, as well as survival in our xenograft model. Next, we used this model to study the effects of As2O3 in vivo.
Results
XPO1 was expressed in the MEC1 cell line and in CLL patients. Expression data suggested that XPO1 was up-regulated inCLL patients compared with normal controls. As2O3 could inhibit the proliferation and induced apoptosis in MEC1 cells, and it down-regulated the expression of XPO1 and survivin in MEC1 cells.XPO1 suppressed by As2O3was associated with enhanced mRNA expression of the pro-apoptotic genes Bax, PUMA and survivin, and suppression of the anti-apoptotic genes BCL-2, BCL-x and XIAP.Overexpression of XPO1 in MEC1 decreased As2O3 -induced apoptosis.Inhibition of XPO1 by selinexorin MEC1 cellsresulted in increasedAs2O3 -induced apoptosis.Furthermore, siRNA knockdown of XPO1 strongly impaired in vivo engraftment of MEC1 cells following transplantation in NSG mice, conferring a survival benefit compared with mice transplanted with control cells.As2O3 could inhibit tumour growth and significantly increased the survival of mice bearing MEC1-derived xenografts by inhibiting XPO1 and survivin.
Conclusion
This is the first report to demonstrate thatAs2O3can induce apoptosis and inhibit proliferation in CLL. The mechanistic effect of As2O3 on CLLresults from the down-regulation of XPO1/survivin pathway signalling.
Session topic: E-poster
Keyword(s): Arsenic trioxide, Chronic lymphocytic leukemia, Survivin
Type: Eposter Presentation
Background
Chronic lymphocytic leukaemia(CLL) is characterized by the progressive accumulation of clonal mature B-cells in the blood, bone marrow, and lymphoid organs and by a highly variable clinical course. Elevated expression of exportin 1 (XPO1/CRM1) has been reported in CLL and correlated with a poor prognosis and resistance to therapy. Inhibition of XPO1 can result in CLL cell death in vitro and increased survival in a CLL mouse model. The efficacy of XPO1 inhibitor for the treatment of diffuse malignant peritoneal mesothelioma may rely on interference with the function of survivin. Our previous work showed that arsenic trioxide(As2O3) induced apoptosis in a CLL cell linetogether with up-regulation of p53 and down-regulation of survivin. Taken together, these findings raise the question of whetherAs2O3 might inhibit CLL by inducing apoptosis via the suppression of XPO1/survivin pathway signalling.
Aims
We sought to investigate whether XPO1/survivin pathway signalling might be involved in the anti-CLL effect induced by As2O3.
Methods
The expression of XPO1 in the MEC1 cell line and primary peripheral blood cells from CLL patients was assessed by qPCR and compared with the expression in purified peripheral normal B-cells. XPO1 siRNA was used to knockdown XPO1 expression in MEC1 cells. XPO1 plasmid transfection was used to overexpress XPO1. Thesurvival and apoptosis rates of MEC1 cells induced by As2O3were determinedby 7-AAD,Annexin V-PI and caspase3/7 analysis. The expression of various genes associated with apoptosis, including Bax, PUMA, survivin, BCL-2, BCL-x and XIAP, were assessed by real-time PCR.XPO1 normal and XPO1 knockdown MEC1 cells were inoculated intravenously intoNOD/scid/γcnull(NSG) mice to establish a human leukaemia xenograft model. We assessed tumour characteristics, including organ infiltration, apoptosis, andexpression of survivin, ki67 and XPO1, as well as survival in our xenograft model. Next, we used this model to study the effects of As2O3 in vivo.
Results
XPO1 was expressed in the MEC1 cell line and in CLL patients. Expression data suggested that XPO1 was up-regulated inCLL patients compared with normal controls. As2O3 could inhibit the proliferation and induced apoptosis in MEC1 cells, and it down-regulated the expression of XPO1 and survivin in MEC1 cells.XPO1 suppressed by As2O3was associated with enhanced mRNA expression of the pro-apoptotic genes Bax, PUMA and survivin, and suppression of the anti-apoptotic genes BCL-2, BCL-x and XIAP.Overexpression of XPO1 in MEC1 decreased As2O3 -induced apoptosis.Inhibition of XPO1 by selinexorin MEC1 cellsresulted in increasedAs2O3 -induced apoptosis.Furthermore, siRNA knockdown of XPO1 strongly impaired in vivo engraftment of MEC1 cells following transplantation in NSG mice, conferring a survival benefit compared with mice transplanted with control cells.As2O3 could inhibit tumour growth and significantly increased the survival of mice bearing MEC1-derived xenografts by inhibiting XPO1 and survivin.
Conclusion
This is the first report to demonstrate thatAs2O3can induce apoptosis and inhibit proliferation in CLL. The mechanistic effect of As2O3 on CLLresults from the down-regulation of XPO1/survivin pathway signalling.
Session topic: E-poster
Keyword(s): Arsenic trioxide, Chronic lymphocytic leukemia, Survivin
Abstract: E1019
Type: Eposter Presentation
Background
Chronic lymphocytic leukaemia(CLL) is characterized by the progressive accumulation of clonal mature B-cells in the blood, bone marrow, and lymphoid organs and by a highly variable clinical course. Elevated expression of exportin 1 (XPO1/CRM1) has been reported in CLL and correlated with a poor prognosis and resistance to therapy. Inhibition of XPO1 can result in CLL cell death in vitro and increased survival in a CLL mouse model. The efficacy of XPO1 inhibitor for the treatment of diffuse malignant peritoneal mesothelioma may rely on interference with the function of survivin. Our previous work showed that arsenic trioxide(As2O3) induced apoptosis in a CLL cell linetogether with up-regulation of p53 and down-regulation of survivin. Taken together, these findings raise the question of whetherAs2O3 might inhibit CLL by inducing apoptosis via the suppression of XPO1/survivin pathway signalling.
Aims
We sought to investigate whether XPO1/survivin pathway signalling might be involved in the anti-CLL effect induced by As2O3.
Methods
The expression of XPO1 in the MEC1 cell line and primary peripheral blood cells from CLL patients was assessed by qPCR and compared with the expression in purified peripheral normal B-cells. XPO1 siRNA was used to knockdown XPO1 expression in MEC1 cells. XPO1 plasmid transfection was used to overexpress XPO1. Thesurvival and apoptosis rates of MEC1 cells induced by As2O3were determinedby 7-AAD,Annexin V-PI and caspase3/7 analysis. The expression of various genes associated with apoptosis, including Bax, PUMA, survivin, BCL-2, BCL-x and XIAP, were assessed by real-time PCR.XPO1 normal and XPO1 knockdown MEC1 cells were inoculated intravenously intoNOD/scid/γcnull(NSG) mice to establish a human leukaemia xenograft model. We assessed tumour characteristics, including organ infiltration, apoptosis, andexpression of survivin, ki67 and XPO1, as well as survival in our xenograft model. Next, we used this model to study the effects of As2O3 in vivo.
Results
XPO1 was expressed in the MEC1 cell line and in CLL patients. Expression data suggested that XPO1 was up-regulated inCLL patients compared with normal controls. As2O3 could inhibit the proliferation and induced apoptosis in MEC1 cells, and it down-regulated the expression of XPO1 and survivin in MEC1 cells.XPO1 suppressed by As2O3was associated with enhanced mRNA expression of the pro-apoptotic genes Bax, PUMA and survivin, and suppression of the anti-apoptotic genes BCL-2, BCL-x and XIAP.Overexpression of XPO1 in MEC1 decreased As2O3 -induced apoptosis.Inhibition of XPO1 by selinexorin MEC1 cellsresulted in increasedAs2O3 -induced apoptosis.Furthermore, siRNA knockdown of XPO1 strongly impaired in vivo engraftment of MEC1 cells following transplantation in NSG mice, conferring a survival benefit compared with mice transplanted with control cells.As2O3 could inhibit tumour growth and significantly increased the survival of mice bearing MEC1-derived xenografts by inhibiting XPO1 and survivin.
Conclusion
This is the first report to demonstrate thatAs2O3can induce apoptosis and inhibit proliferation in CLL. The mechanistic effect of As2O3 on CLLresults from the down-regulation of XPO1/survivin pathway signalling.
Session topic: E-poster
Keyword(s): Arsenic trioxide, Chronic lymphocytic leukemia, Survivin
Type: Eposter Presentation
Background
Chronic lymphocytic leukaemia(CLL) is characterized by the progressive accumulation of clonal mature B-cells in the blood, bone marrow, and lymphoid organs and by a highly variable clinical course. Elevated expression of exportin 1 (XPO1/CRM1) has been reported in CLL and correlated with a poor prognosis and resistance to therapy. Inhibition of XPO1 can result in CLL cell death in vitro and increased survival in a CLL mouse model. The efficacy of XPO1 inhibitor for the treatment of diffuse malignant peritoneal mesothelioma may rely on interference with the function of survivin. Our previous work showed that arsenic trioxide(As2O3) induced apoptosis in a CLL cell linetogether with up-regulation of p53 and down-regulation of survivin. Taken together, these findings raise the question of whetherAs2O3 might inhibit CLL by inducing apoptosis via the suppression of XPO1/survivin pathway signalling.
Aims
We sought to investigate whether XPO1/survivin pathway signalling might be involved in the anti-CLL effect induced by As2O3.
Methods
The expression of XPO1 in the MEC1 cell line and primary peripheral blood cells from CLL patients was assessed by qPCR and compared with the expression in purified peripheral normal B-cells. XPO1 siRNA was used to knockdown XPO1 expression in MEC1 cells. XPO1 plasmid transfection was used to overexpress XPO1. Thesurvival and apoptosis rates of MEC1 cells induced by As2O3were determinedby 7-AAD,Annexin V-PI and caspase3/7 analysis. The expression of various genes associated with apoptosis, including Bax, PUMA, survivin, BCL-2, BCL-x and XIAP, were assessed by real-time PCR.XPO1 normal and XPO1 knockdown MEC1 cells were inoculated intravenously intoNOD/scid/γcnull(NSG) mice to establish a human leukaemia xenograft model. We assessed tumour characteristics, including organ infiltration, apoptosis, andexpression of survivin, ki67 and XPO1, as well as survival in our xenograft model. Next, we used this model to study the effects of As2O3 in vivo.
Results
XPO1 was expressed in the MEC1 cell line and in CLL patients. Expression data suggested that XPO1 was up-regulated inCLL patients compared with normal controls. As2O3 could inhibit the proliferation and induced apoptosis in MEC1 cells, and it down-regulated the expression of XPO1 and survivin in MEC1 cells.XPO1 suppressed by As2O3was associated with enhanced mRNA expression of the pro-apoptotic genes Bax, PUMA and survivin, and suppression of the anti-apoptotic genes BCL-2, BCL-x and XIAP.Overexpression of XPO1 in MEC1 decreased As2O3 -induced apoptosis.Inhibition of XPO1 by selinexorin MEC1 cellsresulted in increasedAs2O3 -induced apoptosis.Furthermore, siRNA knockdown of XPO1 strongly impaired in vivo engraftment of MEC1 cells following transplantation in NSG mice, conferring a survival benefit compared with mice transplanted with control cells.As2O3 could inhibit tumour growth and significantly increased the survival of mice bearing MEC1-derived xenografts by inhibiting XPO1 and survivin.
Conclusion
This is the first report to demonstrate thatAs2O3can induce apoptosis and inhibit proliferation in CLL. The mechanistic effect of As2O3 on CLLresults from the down-regulation of XPO1/survivin pathway signalling.
Session topic: E-poster
Keyword(s): Arsenic trioxide, Chronic lymphocytic leukemia, Survivin
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