Objective To summarize the recent findings of dysregulation of signaling pathways and miRNAs in chronic lymphocytic leukemia （CLL）. Data sources We searched PubMed database with the keywords ＂chronic lymphocytic le...Objective To summarize the recent findings of dysregulation of signaling pathways and miRNAs in chronic lymphocytic leukemia （CLL）. Data sources We searched PubMed database with the keywords ＂chronic lymphocytic leukemia＂, ＂signal pathway＂, or ＂miRNA＂ for relevant articles in recent years.展开更多
Background:TOSO,also named Fas inhibitory molecule 3(FAIM3),has recently been identified as an immunoglobulin M(IgM)Fc receptor(FcμR).Previous studies have shown that TOSO is specifically over-expressed in chronic ly...Background:TOSO,also named Fas inhibitory molecule 3(FAIM3),has recently been identified as an immunoglobulin M(IgM)Fc receptor(FcμR).Previous studies have shown that TOSO is specifically over-expressed in chronic lymphocytic leukemia(CLL).However,the functions of TOSO in CLL remain unknown.The B-cell receptor(BCR)signaling pathway has been reported to be constitutively activated in CLL.Here,we aimed to investigate the functions of TOSO in the BCR signaling pathway and the pathogenesis of CLL.Methods:We over-expressed TOSO in B-cell lymphoma cell lines(Granta-519 and Z138)by lentiviral transduction and knocked down TOSO by siRNA in primary CLL cells.The over-expression and knockdown of TOSO were confirmed at the RNA level by polymerase chain reaction and protein level by Western blotting.Co-immunoprecipitation with TOSO antibody followed by liquid chromatography coupled with tandem mass spectrometry(IP/LCMS)was used to identify TOSO interacting proteins.Western blotting was performed to detect the activation status of BCR signaling pathways as well as B-cell lymphoma 2(BCL-2).Flow cytometry was used to examine the apoptosis of TOSO-over-expressing B lymphoma cell lines and TOSO-down-regulated CLL cells via the staining of Annexin V and 7-AAD.One-way analyses of variance were used for intergroup comparisons,while independent samples t tests were used for two-sample comparisons.Results:From IP/LCMS,we identified spleen tyrosine kinase(SYK)as a crucial candidate of TOSO-interacting protein and confirmed it by co-immunoprecipitation.After stimulation with anti-IgM,TOSO over-expression increased the phosphorylation of SYK,and subsequently activated the BCR signaling pathway,which could be reversed by a SYK inhibitor.TOSO knockdown in primary CLL cells resulted in reduced SYK phosphorylation as well as attenuated BCR signaling pathway.The apoptosis rates of the Granta-519 and Z138 cells expressing TOSO were(8.46±2.90)%and(4.20±1.21)%,respectively,significantly lower than the rates of the control groups,which were(25.20±4.60)%and(19.72±1.10)%,respectively(P<0.05 for both).The apoptosis rate was reduced after knocking down TOSO in the primary CLL cells.In addition,we also found that TOSO down-regulation in primary cells from CLL patients led to decreased expression of BCL-2 as well as lower apoptosis,and vice versa in the cell line.Conclusions:TOSO might be involved in the pathogenesis of CLL by interacting with SYK,enhancing the BCR signaling pathway,and inducing apoptosis resistance.展开更多
Objective： Chronic lymphocytic leukemia （CLL） and mantle cell lymphoma （MCL） cells over-express a guanine exchange factor （GEF）, Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from R...Objective： Chronic lymphocytic leukemia （CLL） and mantle cell lymphoma （MCL） cells over-express a guanine exchange factor （GEF）, Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods： N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor （BCR） and chemokine signaling pathways were compared in the Rasgrf-I over-expressing and a control transfected cell line. Results： Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions： This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells.展开更多
The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Phila?delphia chromosome(Ph) and is a hallmark of chronic myeloid leukemia(CML).In leukemia cells,Ph not only...The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Phila?delphia chromosome(Ph) and is a hallmark of chronic myeloid leukemia(CML).In leukemia cells,Ph not only impairs the physiological signaling pathways but also disrupts genomic stability.This aberrant fusion gene encodes the breakpoint cluster region?proto?oncogene tyrosine?protein kinase(BCR?ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity.The kinase activity is responsible for maintaining proliferation,inhibiting differentia?tion,and conferring resistance to cell death.During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase,the expression patterns of different BCR?ABL1 transcripts vary.Each BCR?ABL1 transcript is present in a distinct leukemia phenotype,which predicts both response to therapy and clinical outcome.Besides CML,the Ph is found in acute lymphoblastic leukemia,acute myeloid leukemia,and mixed?phenotype acute leukemia.Here,we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph?positive leukemia and highlight key findings regarding leukemogenesis.展开更多
基金This study was supported by the grants from the National Natural Science Foundation （No. 81270598）, Natural Science Foundation of Shandong Province, China （No. Y2007C053, No. ZR2009CM059）, and the Scientific ＆Technological Project of Shandong Province, China （No. 2007GG 10002008）.
文摘Objective To summarize the recent findings of dysregulation of signaling pathways and miRNAs in chronic lymphocytic leukemia （CLL）. Data sources We searched PubMed database with the keywords ＂chronic lymphocytic leukemia＂, ＂signal pathway＂, or ＂miRNA＂ for relevant articles in recent years.
基金This work was supported by grants from the National Nature Science Foundation of China(Nos.81200395 and 81970187)Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences grants(No.2017-I2M-3-018)Fundamental Application and Advanced and Technology Research Program of Tianjin(No.15JCYBJC25100)。
文摘Background:TOSO,also named Fas inhibitory molecule 3(FAIM3),has recently been identified as an immunoglobulin M(IgM)Fc receptor(FcμR).Previous studies have shown that TOSO is specifically over-expressed in chronic lymphocytic leukemia(CLL).However,the functions of TOSO in CLL remain unknown.The B-cell receptor(BCR)signaling pathway has been reported to be constitutively activated in CLL.Here,we aimed to investigate the functions of TOSO in the BCR signaling pathway and the pathogenesis of CLL.Methods:We over-expressed TOSO in B-cell lymphoma cell lines(Granta-519 and Z138)by lentiviral transduction and knocked down TOSO by siRNA in primary CLL cells.The over-expression and knockdown of TOSO were confirmed at the RNA level by polymerase chain reaction and protein level by Western blotting.Co-immunoprecipitation with TOSO antibody followed by liquid chromatography coupled with tandem mass spectrometry(IP/LCMS)was used to identify TOSO interacting proteins.Western blotting was performed to detect the activation status of BCR signaling pathways as well as B-cell lymphoma 2(BCL-2).Flow cytometry was used to examine the apoptosis of TOSO-over-expressing B lymphoma cell lines and TOSO-down-regulated CLL cells via the staining of Annexin V and 7-AAD.One-way analyses of variance were used for intergroup comparisons,while independent samples t tests were used for two-sample comparisons.Results:From IP/LCMS,we identified spleen tyrosine kinase(SYK)as a crucial candidate of TOSO-interacting protein and confirmed it by co-immunoprecipitation.After stimulation with anti-IgM,TOSO over-expression increased the phosphorylation of SYK,and subsequently activated the BCR signaling pathway,which could be reversed by a SYK inhibitor.TOSO knockdown in primary CLL cells resulted in reduced SYK phosphorylation as well as attenuated BCR signaling pathway.The apoptosis rates of the Granta-519 and Z138 cells expressing TOSO were(8.46±2.90)%and(4.20±1.21)%,respectively,significantly lower than the rates of the control groups,which were(25.20±4.60)%and(19.72±1.10)%,respectively(P<0.05 for both).The apoptosis rate was reduced after knocking down TOSO in the primary CLL cells.In addition,we also found that TOSO down-regulation in primary cells from CLL patients led to decreased expression of BCL-2 as well as lower apoptosis,and vice versa in the cell line.Conclusions:TOSO might be involved in the pathogenesis of CLL by interacting with SYK,enhancing the BCR signaling pathway,and inducing apoptosis resistance.
文摘Objective： Chronic lymphocytic leukemia （CLL） and mantle cell lymphoma （MCL） cells over-express a guanine exchange factor （GEF）, Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods： N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor （BCR） and chemokine signaling pathways were compared in the Rasgrf-I over-expressing and a control transfected cell line. Results： Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions： This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells.
基金supported by the China Central Budget Recruitment Program of High?Level Overseas Talent (GDW 201221022066 to Q.Liu)the National Basic Research Program of China (973 Program:No.2012CB967000 to Q.Liu)+2 种基金the National Natural Science Foundation of China (NNSF No.81130040 to Q.Liu and No.81201686 to J.Xu)the Program for Changjiang Scholars and Innovative Research Team in Universities (ITR 13049 to Q.Liu)the Liaoning (NSF 2014029102 to Q.Liu)
文摘The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Phila?delphia chromosome(Ph) and is a hallmark of chronic myeloid leukemia(CML).In leukemia cells,Ph not only impairs the physiological signaling pathways but also disrupts genomic stability.This aberrant fusion gene encodes the breakpoint cluster region?proto?oncogene tyrosine?protein kinase(BCR?ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity.The kinase activity is responsible for maintaining proliferation,inhibiting differentia?tion,and conferring resistance to cell death.During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase,the expression patterns of different BCR?ABL1 transcripts vary.Each BCR?ABL1 transcript is present in a distinct leukemia phenotype,which predicts both response to therapy and clinical outcome.Besides CML,the Ph is found in acute lymphoblastic leukemia,acute myeloid leukemia,and mixed?phenotype acute leukemia.Here,we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph?positive leukemia and highlight key findings regarding leukemogenesis.
