OBJECTIVEThis article aimed to review the biological characteristics of enhancer of zests homolog 2 (EZH2), and the transcriptional repression mechanism of action of EZH2 in tumors, particularly in the progression of lymphoma.

DATA SOURCESThe data cited in this review were mainly obtained from the articles listed in PubMed and HighWare that were published from March 2004 to April 2012. The search terms were "enhancer of zests homolog 2", "polycomb group", and "lymphoma".

STUDY SELECTIONArticles regarding the mechanism of EZH2 in post-transcriptional modification, functions of polycomb group proteins, and the roles of EZH2 in lymphoma were selected.

RESULTSEZH2 acts as oncogene and involved in many kinds of tumors. Moreover, it plays an important role in tumorigenesis and lymphomagenesis by promoting the proliferation and aggressiveness of neoplastic cells, facilitating malignant tumor cell diffusion, and mediating transcriptional silencing.

CONCLUSIONEZH2 mediated transcriptional repression through its methyltransferase activity at the chromatin level has certain influence on lymphoma, and there might exist a therapeutic window for the development of new agents and identification of novel diagnostic markers based on EZH2.

Disease Progression ; Enhancer of Zeste Homolog 2 Protein ; Epigenesis, Genetic ; Histones ; metabolism ; Humans ; Lymphoma ; etiology ; genetics ; Methylation ; Mutation ; Polycomb Repressive Complex 2 ; genetics ; physiology

OBJECTIVETo study the expression of β-integrin family members in children with T-cell acute lymphoblastic leukemia (T-ALL) and their significance.

METHODSQuantitative real-time PCR analyses were performed to assess the expression levels of β-integrin family members in bone marrow samples from 22 children with newly-diagnosed T-ALL and 21 controls (16 children with non-malignant hematologic disease and 5 healthy donors with bone marrow transplantation). Jurkat cells were treated with integrin inhibitor arginine-glycine-aspartate (Arg-Gly-Asp, RGD) peptide. The cell viability and apoptosis rate were determined by CCK8 assay and flow cytometry respectively.

RESULTSThe mRNA levels of integrins β, β, and βwere significantly lower in children with T-ALL than in controls (P<0.05). In T-ALL patients, high integrin βexpression was associated with lower white blood cell counts (<100×10/L), minimal residual disease (MRD) positivity, and day 33 bone marrow negative remission (P<0.05). In T-ALL patients, higher integrin βexpression was associated with relapse of T-ALL (P<0.05). Based on survival curve analysis, higher integrin βexpression was related to lower event-free survival and overall survival rates. RGD peptide treatment inhibited the proliferation of Jurkat cells and increased their apoptosis rate (P<0.05).

CONCLUSIONSβ-Integrin may play a role in the occurrence and development of T-ALL by affecting cell proliferation and apoptosis. The expression of integrin β5 is closely related to the risk of relapse of T-ALL. The expression of integrin β3 is closely related the treatment response and prognosis of T-ALL.

Child ; Child, Preschool ; Female ; Humans ; Integrin beta Chains ; genetics ; physiology ; Jurkat Cells ; Male ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; etiology ; metabolism ; mortality ; RNA, Messenger ; analysis

Met tyrosine kinase receptor, the receptor of hepatocyte growth factor/scatter factor (HGF/SF), is present in mouse tissues as two major isoforms differing by a 47-aminoacid segment in the juxtamembrane domain via alternative splicing of exon 14. We found that the smaller isoform of Met (Sm-Met) was highly transformable in both in vitro and in vivo tumorigenesis assays. In this report, close examination of the transforming activity of the Sm-Met showed that the expression of Sm-Met conferred the cells serum independence and anti- apoptotic property when treated with doxorubicin. These properties of Sm-Met seemed to be originated from its far longer maintenance of tyrosine kinase activity after the binding of HGF/SF. Interestingly, the longer maintenance of activated status was accompanied with more increase of tyrosine phosphorylation of Stat3 protein. Moreover, we have tried to find (an) animal tumorigenesis model(s) showing the increase in the expression of this transforming variant of Met. In gamma-ray-induced mouse thymic lymphoma model, the expression of the mRNAs for Sm-Met was significantly increased as well as those of wild type Met and HGF/SF, suggesting a possible role of the Sm-Met in tumorigenesis in vivo.
Animals ; *Apoptosis ; Cell Proliferation ; Cell Survival ; *Cell Transformation, Neoplastic ; DNA-Binding Proteins/metabolism ; Doxorubicin/pharmacology ; Hepatocyte Growth Factor/pharmacology ; Lymphoma/*etiology/genetics/metabolism ; Mice ; NIH 3T3 Cells ; Phosphorylation ; Protein Isoforms/genetics/metabolism ; Proto-Oncogene Protein c-met/genetics/*metabolism ; RNA, Messenger/analysis/metabolism ; Research Support, Non-U.S. Gov't ; Serum/metabolism ; Thymus Gland ; Trans-Activators/metabolism

Apoptosis ; Fas Ligand Protein ; metabolism ; Germinal Center ; pathology ; Humans ; Janus Kinases ; metabolism ; Lymphoma, Large B-Cell, Diffuse ; etiology ; genetics ; metabolism ; pathology ; NF-kappa B ; metabolism ; Positive Regulatory Domain I-Binding Factor 1 ; Proto-Oncogene Proteins c-bcl-6 ; genetics ; metabolism ; Repressor Proteins ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Translocation, Genetic ; fas Receptor ; metabolism

OBJECTIVETo study the clinicopathologic features of 66 cases of primary systemic anaplastic large cell lymphoma (ALCL), with emphasis on the differences between ALK-positive and ALK-negative cases.

METHODSThe clinical data of 66 cases of ALCL was analyzed. The histologic features were reviewed. Immunohistochemical study for CD30, ALK protein, epithelial membrane antigen, CD2, CD3, granzyme B and TIA-1 was carried out. In-situ hybridization for small mRNA of Epstein-Barr virus (EBER) was also performed. The chromosomal abnormalities were studied by fluorescence in-situ hybridization (FISH). The differences between ALK-positive and ALK-negative cases were statistically analyzed.

RESULTSThere were 48 cases of ALK-positive ALCL and 18 cases of ALK-negative ALCL. The patients with ALK-positive ALCL were younger than those with ALK-negative ALCL (P < 0.05), with the median age being 18 years and 36 years, respectively. Fever, especially hyperpyrexia, was more commonly observed in ALK-positive ALCL patients than in ALK-negative ALCL patients (33 cases versus 4 cases, P < 0.05). The overall survival rate and median duration of survival in patients with ALK-positive ALCL were higher and longer than those in patients with ALK-negative ALCL (80% versus 71%; 21 months versus 12.5 months, P > 0.05). There were however no significant differences in histology between ALK-positive ALCL and ALK-negative ALCL. Histologically, most cases showed diffuse growth pattern. Nodular pattern was demonstrated in a minority of cases. "Hallmark" cells were seen in most of the ALCL cases. Focal necrosis and myxomatous stroma were identified in a few cases. Most ALK-positive cases belonged to the common variant (35 cases). A small number represented lymphohistiocytic variant (8 cases). Small cell variant and sarcomatoid subtype were found only in few cases (3 cases and 2 cases, respectively).On the other hand, common variant (17 cases) constituted the majority of ALK-negative ALCL. Lymphohistiocytic variant was seen in only 1 case. Immunohistochemical study showed that ALK-positive ALCL always expressed CD30 and epithelial membrane antigen. ALK-positive ALCL more often expressed epithelial membrane antigen (100% versus 72%; P < 0.05) but less so for T-cell markers (including CD2, CD3, CD43 and CD45RO). Cytotoxic molecules were more commonly expressed in ALK-positive ALCL (P > 0.05). EBER was negative in all cases studied. FISH showed that in ALK-positive ALCL, 1 case had normal ALK gene, 1 had deletion and multicopy and 2 had deletion. On the other hand, 1 case of ALK-negative ALCL had normal ALK gene.

CONCLUSIONSWhile there are no significant morphologic differences between ALK-positive ALCL and ALK-negative ALCL, the clinical features, immunophenotypes and genetic features of both groups vary. These differences are helpful in guiding the differential diagnosis.

Adolescent ; Adult ; Age Factors ; Child ; Child, Preschool ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Gene Deletion ; Humans ; Ki-1 Antigen ; metabolism ; Lymphoma, Large-Cell, Anaplastic ; complications ; drug therapy ; genetics ; metabolism ; pathology ; Male ; Malignant Hyperthermia ; etiology ; Middle Aged ; Mucin-1 ; metabolism ; Neoplasm Recurrence, Local ; Protein-Tyrosine Kinases ; genetics ; metabolism ; Receptor Protein-Tyrosine Kinases ; Survival Rate ; Young Adult

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