OBJECTIVETo investigate if WAVE1 is involved in mult drug-resistance (MDR) of human leukemia cell line K562/A02.

METHODSThe level of WAVE1 in K562 and K562/A02 cells was assayed by Western blot and RT-PCR; K562 cells and K562/A02 cells were transient transfected with pEFBOS-WAVE1 reconstructed plasmid or specifically siRNA to WAVE1. 50% inhibition concentration (IC50) of doxorubicin on K562/A02 was determined by WST-8 assay. Hoechst33258 staining was used to examine cell morphological changes and to calculate percentage of apoptotic nuclei. The mRNA level of mdrl was assayed by RT-PCR. The Bcl-2 protein was assayed by Western blot.

RESULTS1. The WAVE1 expression at mRNA and protein level in K562/A02 cells was increased by about 70% and 63% respectively as compared with that in K562 cells. 2. Overexpression of WAVE1 in K562 cells by transient transfection significantly increased the resistance to doxorubicin, and increased IC50 from (0.05 +/- 0.00) microg/ml to (2.99 +/- 0.12) microg/ml, and at 1 microg/ml or 5 microg/ml of doxorubicin treatment, cell apoptotic nuclei rate was decreased by 30% or 35% respectively. 3. Suppression of WAVE1 in K562/A02 cells by siRNA resulted in a reversal of MDR to doxorubicin, and decreased IC50 from (4.29 +/- 0.15) microg/ml to (1.85 +/- 0.07) microg/ml, and at 1 microg/ml or 5 microg/ml of doxorubicin treatment, cell apoptotic nuclei rate was increased by 24% or 21% respectively. 4. Overexpression of WAVE1 in K562 cells significantly increased the mdrl mRNA and the Bcl-2 protein, and suppression of WAVE1 in K562/A02 cells by siRNA decreased the mRNA and the protein.

CONCLUSIONWAVE1 involves in the MDR mechanisms in K562/A02 leukemia cells through regulation the level of mdrl and Bcl-2.

Apoptosis ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Genetic Vectors ; Humans ; K562 Cells ; Plasmids ; genetics ; RNA Interference ; RNA, Messenger ; genetics ; Transfection ; Wiskott-Aldrich Syndrome Protein Family ; genetics ; metabolism

OBJECTIVETo investigate role of WASP family verprolin homologous protein 1 (WAVE1) in K562 leukemia cell invasion and its mechanism.

METHODSImmunofluorescence method was used to detect the distribution of WAVE1 and MMP-2 in the cells. K562 cells were transfected with pcDNA3. 1-WAVE1 reconstructed plasmid or with specific siRNA to WAVE1 gene. The invasion ability of K562 cells was examined by Transwell assay. The expression level of WAVE1 and MMP-2 in K562 cells was assayed by real-time PCR and Western blot.

RESULTS(1) WAVE1 and MMP-2 mainly expressed and co-localized in the cell membrane; (2) 24 h and 48 h after transfected with pcDNA3. 1-WAVE1, the MMP-2 mRNA level in K562 cells increased by 295% and 198% while its protein increased by 80% and 23% respectively as compared with control K562 cells. At the same time point after transfected with specific siRNA, the MMP-2 mRNA level decreased by 81% and 28%, and its protein decreased by 36% and 53% respectively as compared with control. (3) The invasion ability of K562 cells was enhanced after transfected with pcDNA3. 1-WAVE1 and depressed after transfected with the specific siRNA.

CONCLUSIONThe co-localization of WAVE1 and MMP-2 in K562 cells suggests they coordinate in functions; WAVE1 may involve in the migration and invasion of K562 cells through regulating the expression level of MMP-2.

Humans ; K562 Cells ; Leukemic Infiltration ; genetics ; metabolism ; physiopathology ; Matrix Metalloproteinase 2 ; genetics ; metabolism ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Transfection ; Wiskott-Aldrich Syndrome Protein Family ; genetics ; metabolism

OBJECTIVETo study the expression of WAVE1 and p22phox in peripheral blood mononuclear cells (PBMCs) in children with acute lymphocytic leukemia (ALL) and the relationship of WAVE1 with oxidative stress.

METHODSReal-time PCR was used for detecting WAVE1 and p22phox expression in PBMCs in 41 children with ALL and 10 normal controls. Plasma activity of superoxide dismutase (SOD) was measured by the xanthine oxidase method. Plasma activity of GSH-Px was measured by the DTNB reaction test.

RESULTSThe expression of WAVE1 and p22phox was significantly higher in the active ALL groups (newly diagnosed and relapse ALL) than that in the normal control and the complete remission (CR) ALL groups (<0.01). The CR ALL group showed increased WAVE1 and p22phox expression than those in the normal control group (<0.05). Plasma activities of SOD (22.62+/-7.39 U/mL) and GSH-Px (91.73+/-28.88 micromol/L) in the active ALL group were significantly lower than those in the normal control (166.35+/-27.93 U/mL and 490.94+/-39.38 micromol/L, respectively) and the CR ALL groups (107.11+/-28.57 U/mL and 267.56+/-82.64 micromol/L, respectively) (<0.01). WAVE1 expression was positively correlated with p22phox expression (r=0.34, <0.05) but negatively correlated with plasma activities of SOD and GSH-Px ( r=-0.336 and-0.408, respectively; <0.05).

CONCLUSIONSWAVE1 and p22phox expression in PBMCs increased and was associated with the disease course in children with ALL. Oxidative stress may be involved in the regulation of WAVE1 expression in ALL children.

Adolescent ; Child ; Child, Preschool ; Female ; Glutathione Peroxidase ; blood ; Humans ; Infant ; Leukocytes, Mononuclear ; metabolism ; Male ; NADPH Oxidases ; genetics ; Oxidative Stress ; Polymerase Chain Reaction ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; metabolism ; RNA, Messenger ; blood ; Superoxide Dismutase ; blood ; Wiskott-Aldrich Syndrome Protein Family ; genetics

OBJECTIVEMultidrug resistance (MDR) is one of the primary causes of suboptimal outcomes in chemotherapy of children with acute myeloblastic leukemia (AML). The mechanisms of drug transport resistance may chiefly contribute to MDR. Expression and/or activity of P-glycoprotein (P-gp), multiple resistance-associated protein-1 (MRP1), lung-resistance related protein (LRP) and breast cancer resistance protein (BCRP) have been considered to be associated with unfavourable outcomes in pediatric AML patients. In previous studies, we found WASP-family verprolin-homologous protein-1 (WAVE1) was involved in the MDR mechanisms in K562/A02 leukemia cells. To investigate the expression of WAVE1, P-gp, MRP1, LRP/MVP and BCRP; and if WAVE1 is involved in MDR of human leukemia cell.

METHODSWAVE1, P-gp, MRP1, LRP, BCRP mRNA and protein expression in bone marrow mononuclear cells (BMMCs) were measured by real-time fluorescence quantitative PCR (RQ-PCR) and Western blot in a cohort of 52 children with acute myeloblastic leukemia. During follow-up, of the 52 patients, 21 were documented as being relapsing or refractory, and 31 were induced into complete continuous remission. Furthermore, HL60 cells and HL60/ADR cells were transiently transfected with PCDNA3.1-WAVE1 reconstructed plasmid and specifically siRNA to WAVE1 respectively, and the expression of WAVE1, MRP1 and BCRP before and after transfection was assessed by real-time PCR and Western blot analysis.

RESULTS(1) The expression levels of WAVE1, P-gp, MRP, LRP and BCRP in refractory/relapsing group were much higher than that in complete continuous remission (CCR) group. (2) WAVE1 mRNA and protein expression in BMMCs of children were at higher levels when they were newly diagnosed or relapsed, compared with complete continuous remission. (3) The WAVE1 expression at mRNA and protein level in HL60/ADR cells was increased by about 353% and 95% respectively as compared with that in HL60 cells. (4) Overexpression of WAVE1 in HL60 cell lines upregulated the expression levels of MRP and BCRP (MRP mRNA and protein level were increased by about 16.54 times and 129% respectively, BCRP was increased by 4.93 times and 96%); whereas suppression of WAVE1 expression by RNA interference downregulated the expression levels of MRP1 and BCRP (MRP mRNA and protein level was only 11% and 43% of pre-disturbance respectively, BCRP was 14% and 71%).

CONCLUSIONSHigher levels of WAVE1 in the BM indicate an unfavorable prognosis in children with AML. WAVE1 is related to the development of AML and involved in the MDR mechanisms, and regulates the level of MRP1 and BCRP.

Adolescent ; Child ; Child, Preschool ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Female ; Humans ; Infant ; Leukemia, Myeloid, Acute ; genetics ; Male ; RNA, Small Interfering ; Wiskott-Aldrich Syndrome Protein Family ; genetics

OBJECTIVETo investigate whether WASP/Verprolin homologous protein 1 (WAVE1) plays a role in the pathogenesis of childhood acute lymphoblastic leukemia (ALL).

METHODSWAVE1 mRNA and protein expression in bone marrow mononuclear cells (BMMCs) was measured by RT-PCR and Western blotting respectively in 4 children with ALL relapse, 15 children with ALL in complete remission (CR) and 40 children with newly diagnosed ALL. Ten normal bone marrow samples were used as controls. Jurkat cells were treated with different concentrations of adriamycin (ADM). The cell proliferation was detected with MTT. The apoptosis rate was measured by flow cytometry. WAVE1 mRNA and protein expression of Jurkat cells treated with ADM was detected by RT-PCR and Western blotting respectively.

RESULTSWAVE1 was not expressed or weakly expressed in BMMCs from normal controls and patients with ALL in CR. Higher WAVE1 mRNA and protein expression was found in BMMCs from patients with newly diagnosed ALL and patients with relapse ALL when compared with the controls and the patients in CR (P<0.01). ADM significantly inhibited the proliferation of the Jurkat cells and the inhibitory effect was dose-and time-dependent (P<0.05). After ADM treatment for 24 hrs, the percentage of apoptosis cells increased significantly and WAVE1 mRNA and protein expression of Jurkat cells decreased significantly when compared with the untreated controls (P<0.05).

CONCLUSIONSThe WAVE1 expression increased in children with ALL. WAVE1 may be related to the development of ALL and may be severed as a marker for the evaluation of the severity of ALL in children.

Adolescent ; Antibiotics, Antineoplastic ; pharmacology ; Apoptosis ; drug effects ; Blotting, Western ; Cell Proliferation ; drug effects ; Child ; Child, Preschool ; Doxorubicin ; pharmacology ; Female ; Humans ; Infant ; Jurkat Cells ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; etiology ; metabolism ; RNA, Messenger ; analysis ; Wiskott-Aldrich Syndrome Protein Family ; analysis ; genetics ; physiology

Humans ; Infant, Newborn ; Male ; Wiskott-Aldrich Syndrome ; diagnosis ; genetics ; therapy ; Wiskott-Aldrich Syndrome Protein ; genetics

Humans ; Mutation ; Wiskott-Aldrich Syndrome ; genetics ; Wiskott-Aldrich Syndrome Protein ; genetics

OBJECTIVE: To study the clinical features of Wiskott-Aldrich syndrome (WAS) in children. METHODS: A retrospective analysis was performed for the clinical data of 13 children with WAS. RESULTS: All 13 children were boys, with a median age of onset of 3 months (range 1-48 months) and a median age of 24 months (range 1-60 months) at the time of diagnosis. Of the 13 children, only 3 had typical WAS and the remaining 10 children had X-linked thrombocytopenia (XLT). The mean WAS score was 2 (range 1-3), the mean platelet count was 20.5×10/L [range (13-46)×10/L], and the mean platelet volume was 8.1 fl (range 6.7-12.1 fl). Lymphocyte subsets and immunoglobulins were measured for 4 children, among whom 1 (25%) had a reduction in both the percentage of CD3T cells per lymphocyte and lymphocyte per nuclear cells, 1(25%) had a reduction in CD3CD56 NK cells. Among these 4 children, 1 (25%) had an increase in IgG, 2 (50%) had a reduction in IgM, 1 (25%) had a reduction in IgA, and 4 (100%) had an increase in IgE. A total of 14 gene mutations belonging to 13 types were found in 13 children, among which there were 9 missense mutations (65%), 2 splicing mutations (14%), 2 nonsense mutation (14%), and 1 frameshift mutation (7%). The median follow-up time was 39 months (range 3-62 months), and all 13 children survived. CONCLUSIONS Children with WAS often have a young age of onset, and most of them are boys. Major clinical features include thrombocytopenia with a reduction in platelet volume. Missense mutation is the main type of gene mutation.
Child, Preschool ; Humans ; Infant ; Male ; Mutation ; Retrospective Studies ; Thrombocytopenia ; Wiskott-Aldrich Syndrome ; Wiskott-Aldrich Syndrome Protein

OBJECTIVEThis study investigated the history and gene mutations of a family with X-linked thrombocytopenia, in order to understand the clinical characteristic and molecular pathogenesis of the disease.

METHODSA three-generation X-linked thrombocytopenia family with 13 family members was investigated using PCR-DNA direct sequencing method to screen the exons of WASP gene for mutation analysis.

RESULTSThe WASP gene sequencing of the proband revealed a missense mutation in exon 2 (G291A), resulting in a change of amino acid 86 from arginine to histidine. The patient's mother was the carrier of the heterozygosis mutation in X-chromosome.

CONCLUSIONSWASP mutations may be attributed to the molecular mechanism of X-linked thrombocytopenia. G291A is one of the mutations of WASP.

Genetic Diseases, X-Linked ; genetics ; Humans ; Infant ; Male ; Mutation ; Thrombocytopenia ; genetics ; Wiskott-Aldrich Syndrome ; genetics ; Wiskott-Aldrich Syndrome Protein ; genetics

OBJECTIVETo detect potential mutation of the WAS gene in a Chinese family affected with Wiskott-Aldrich syndrome.

METHODSPeripheral blood samples were collected from the proband and his family members. All exons and flanking regions of the WAS gene were subjected to PCR amplification - Sanger sequencing as well as restriction endonuclease analysis. Plasma level of B-cell activating factor (BAFF) was also determined for all family members.

RESULTSA hemizygous mutation (c.257G>A) of the WAS gene was identified in all patients from the family, for which the patient's mother was heterozygous. The same mutation was not found among healthy members of the family. Compared with unaffected members, all patients had a higher level of BAFF.

CONCLUSIONThe c.257G>A mutation of the WAS gene probably underlies the Wiskott-Aldrich syndrome in this family.

B-Cell Activating Factor ; blood ; Child, Preschool ; Heterozygote ; Humans ; Male ; Mutation ; Wiskott-Aldrich Syndrome ; genetics ; Wiskott-Aldrich Syndrome Protein ; genetics