scholarly journals BCL2 translocations in leukemias of mature B cells

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3682-3688 ◽  
Author(s):  
MJ Dyer ◽  
VJ Zani ◽  
WZ Lu ◽  
A O'Byrne ◽  
S Mould ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Prognostic Significance ◽  
Lymphocytic Leukemia ◽  
Chain Gene ◽  
Light Chain Gene ◽  
Prolymphocytic Leukemia ◽  
Hodgkin's Lymphomas ◽  
A Minor ◽  
Bcl2 Gene

Abstract Although translocations of the BCL2 gene are frequent in B-cell non- Hodgkin's lymphomas (B-NHL) the incidence, nature, and prognostic significance of similar translocations in the phenotypically related chronic leukemias of mature B cells are unknown. Therefore, we examined 170 cases of B-cell chronic lymphocytic leukemia (B-CLL), 7 cases of B- cell prolymphocytic leukemia (B-PLL), 25 cases of hairy cell leukemia (HCL) and 22 cases of splenic lymphoma with villous lymphocytes (SLVL) with defined cytogenetic abnormalities by DNA blot using both 5′ and 3′ BCL2 probes to search for rearrangement of the BCL2 locus. Translocation t(14;18) (q32.3;q21.3) was detected cytogenetically in 3 cases of B-CLL. All had breakpoints in the 3′ region of BCL2, mapping between the major breakpoint region (MBR) and the minor cluster region (mcr), the breakpoint clusters commonly detected in B-NHL. In 2 of the 3 cases, the breakpoint within BCL2 was mapped to a 1.0-kb EcoRI- HindIII fragment indicating a clustering of breakpoints. Two cases of B- CLL had cytogenetically detectable t(2;18)(p11;q21.3) or t(18;22)(q21.3;q11). Both had rearranged the 5′ region of the BCL2 gene to the corresponding lg light-chain gene. Molecular cloning of the t(18;22)(q21.3;q11) showed that the translocation disrupted the BCL2 promoter region and the first untranslated BCL2 exon. Nevertheless, high levels of BCL2 protein were seen in this case. Only 2 other cases in whom cytogenetic analysis was not successful showed rearrangement of the 5′ region of BCL2, an overall incidence of 2.3%. No cases of B-PLL, HCL, or SLVL showed either 5′ or 3′ BCL2 rearrangement. These data confirm the cytogenetic observations that translocations involving the BCL2 locus in all forms of leukemia of mature B cells are rare, and limited to a minor subset of B-CLL. BCL2 translocations in B-CLL involve hot spots of recombination of both the 5′ and 3′ regions of the BCL2 gene, which are distinct from those commonly seen in B-NHL, suggesting distinct pathogenic mechanisms.

scholarly journals BCL2 translocations in leukemias of mature B cells

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3682-3688 ◽  
Author(s):  
MJ Dyer ◽  
VJ Zani ◽  
WZ Lu ◽  
A O'Byrne ◽  
S Mould ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Prognostic Significance ◽  
Lymphocytic Leukemia ◽  
Chain Gene ◽  
Light Chain Gene ◽  
Prolymphocytic Leukemia ◽  
Hodgkin's Lymphomas ◽  
A Minor ◽  
Bcl2 Gene

Although translocations of the BCL2 gene are frequent in B-cell non- Hodgkin's lymphomas (B-NHL) the incidence, nature, and prognostic significance of similar translocations in the phenotypically related chronic leukemias of mature B cells are unknown. Therefore, we examined 170 cases of B-cell chronic lymphocytic leukemia (B-CLL), 7 cases of B- cell prolymphocytic leukemia (B-PLL), 25 cases of hairy cell leukemia (HCL) and 22 cases of splenic lymphoma with villous lymphocytes (SLVL) with defined cytogenetic abnormalities by DNA blot using both 5′ and 3′ BCL2 probes to search for rearrangement of the BCL2 locus. Translocation t(14;18) (q32.3;q21.3) was detected cytogenetically in 3 cases of B-CLL. All had breakpoints in the 3′ region of BCL2, mapping between the major breakpoint region (MBR) and the minor cluster region (mcr), the breakpoint clusters commonly detected in B-NHL. In 2 of the 3 cases, the breakpoint within BCL2 was mapped to a 1.0-kb EcoRI- HindIII fragment indicating a clustering of breakpoints. Two cases of B- CLL had cytogenetically detectable t(2;18)(p11;q21.3) or t(18;22)(q21.3;q11). Both had rearranged the 5′ region of the BCL2 gene to the corresponding lg light-chain gene. Molecular cloning of the t(18;22)(q21.3;q11) showed that the translocation disrupted the BCL2 promoter region and the first untranslated BCL2 exon. Nevertheless, high levels of BCL2 protein were seen in this case. Only 2 other cases in whom cytogenetic analysis was not successful showed rearrangement of the 5′ region of BCL2, an overall incidence of 2.3%. No cases of B-PLL, HCL, or SLVL showed either 5′ or 3′ BCL2 rearrangement. These data confirm the cytogenetic observations that translocations involving the BCL2 locus in all forms of leukemia of mature B cells are rare, and limited to a minor subset of B-CLL. BCL2 translocations in B-CLL involve hot spots of recombination of both the 5′ and 3′ regions of the BCL2 gene, which are distinct from those commonly seen in B-NHL, suggesting distinct pathogenic mechanisms.

scholarly journals Ras Mediates Effector Pathways Responsible for Pre-B Cell Survival, Which Is Essential for the Developmental Progression to the Late Pre-B Cell Stage

2000 ◽  
Vol 192 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Hitoshi Nagaoka ◽  
Yoshimasa Takahashi ◽  
Reiko Hayashi ◽  
Tohru Nakamura ◽  
Kumiko Ishii ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Survival ◽  
Chain Gene ◽  
B Cell Differentiation ◽  
Antigen Receptors ◽  
Cell Stage ◽  
Light Chain Gene ◽  
B Cell Survival ◽  
Effector Pathways

Ras is essential for the transition from early B cell precursors to the pro-B stage, and is considered to be involved in the signal cascade mediated by pre-B cell antigen receptors. To examine the role of p21ras in the late stage of B cell differentiation, we established transgenic mice (TG) expressing a dominant-inhibitory mutant of Ha-ras (Asn-17 Ha-ras) in B lineage cells at high levels after the early B cell precursor stage. Expression of p21Asn-17 Ha-ras was associated with a prominent reduction in the number of late pre-B cells, but had little effect on proliferation of early pre-B cells. Inhibition of p21ras activity markedly reduced the life span of pre-B cells, due, at least in part, to downregulation of the expression of an antiapoptotic protein, Bcl-xL. Thus, the apparent role for p21ras activity in pre-B cell survival may explain the decreased numbers of late pre-B cells in Asn-17 Ha-ras TG. Consistent with this possibility, overexpression of Bcl-2 in Asn-17 Ha-ras TG reversed the reduction in the number of late pre-B cells undergoing immunoglobulin light chain gene (IgL) rearrangement and progressing to immature B cells. These results suggest that p21ras mediates effector pathways responsible for pre-B cell survival, which is essential for progression to the late pre-B and immature B stages.

scholarly journals The basic study on kappa-lambda imaging by delta-curve for the detection of a monoclonal B-cell population in the peripheral blood

Blood ◽  
1988 ◽  
Vol 72 (5) ◽  
pp. 1461-1466 ◽  
Author(s):  
M Nakano ◽  
S Kuge ◽  
S Kuwabara ◽  
M Yaguchi ◽  
Y Kawanishi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Basic Study ◽  
Minor Population ◽  
D Values ◽  
A Minor ◽  
D Value

Abstract Recently, kappa-lambda analysis with the “D” value was developed by Ault to detect a minor population of malignant B cells in peripheral blood. This analysis is based on the Kolmogorov-Smirnov test, and the D value is calculated by a flowcytometer and a computer. We have recently devised a more sensitive parameter for the kappa-lambda analysis than the D value called the delta-curve (delta c); the delta c applies the same principle as that of the D value. Mixing experiments with kappa- type and lambda-type chronic lymphocytic leukemia cells revealed that the delta c could not only detect a minor population of malignant kappa- B cells, but also that of malignant lambda-B cells using more sensitivity than the D value. A total of 49 blood samples obtained from 27 patients with various B-cell malignancies were investigated. D values were abnormal in 37% of all samples, while abnormal patterns of the delta c were recognized in 71%. On the other hand, 59% of samples obtained from the patients with B-cell lymphoma in aleukemic phase showed abnormal delta c, whereas D values exceeded the upper limit of the normal value in only 15% of the samples. It was suggested that the delta c could detect 3% to 7% of malignant B cells that were mixed with a population of normal lymphocytes.

scholarly journals Expression and release of CD27 in human B-cell malignancies

Blood ◽  
1993 ◽  
Vol 82 (11) ◽  
pp. 3430-3436 ◽  
Author(s):  
MH van Oers ◽  
ST Pals ◽  
LM Evers ◽  
CE van der Schoot ◽  
G Koopman ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Growth Factor Receptor ◽  
Lymphocytic Leukemia ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Grade ◽  
B Cell Malignancies ◽  
Variable Intensity ◽  
Hodgkin's Lymphomas

Abstract CD27, a transmembrane disulfide-linked 55-kD homodimer, belongs to the nerve growth factor-receptor family, a group of homologous molecules involved in lymphocyte differentiation and selection. It is expressed on mature thymocytes, peripheral blood T cells, and a subpopulation of B cells. We investigated the expression of CD27 on malignant B cells representative for a broad range of stages in physiologic antigen- independent and -dependent B-cell development. In normal lymphoid tissue CD27+ B cells were only found in the peripheral blood (29.8% +/- 10.8%, n = 13) and in germinal centers. With the exception of pro-B and the majority of pre-pre-B acute lymphocytic leukemias and of myelomas, CD27 expression of variable intensity was detected on almost all immature and mature malignant B cells tested. Moreover, using a sandwich enzyme-linked immunosorbent assay we could show the presence of sometimes very high (up to 6,000 U/mL; normal values < 190 U/mL) amounts of the soluble 28- to 32-kD form of CD27 (sCD27) in the sera of patients with B-cell malignancies. The highest levels of sCD27 were observed in patients with chronic lymphocytic leukemia and low-grade non-Hodgkin's lymphomas. Most importantly, both in transversal and longitudinal studies, we found a strong correlation between sCD27 levels in the serum and tumor load, indicating that sCD27 can be used as a disease-marker in patients with acute and chronic B-cell malignancies.

Upregulation of Human Pim-2 in B-CLL, Involves Interactions between Oct-1, Oct-2, Bob-1 and NF-kB.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1916-1916
Author(s):  
Yosef Dicken ◽  
Amos M. Cohen ◽  
Hanna Bessler ◽  
Daphna Levi-Hirsh ◽  
Ariela Arad ◽  
...  
Keyword(s):  
Transcription Factor ◽  
B Cells ◽  
B Cell ◽  
Promoter Region ◽  
Lymphocytic Leukemia ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Cell Extracts ◽  
Hodgkin's Lymphomas

Abstract hPim-2 is a proto-oncogene that encodes a serine/threonine kinase and inhibits apoptosis by phosphorylation of BAD. We have shown that hPim is upregulated in human non-Hodgkin’s lymphomas (NHL) and in chronic lymphocytic leukemia (B-CLL) and its cellular transcript levels in B-CLL correlates with lymphocyte doubling time. We found no mutations in the promoter region of hPim-2 in B-cells of 30 patients with CLL (~2000 bp upstream). The proximal promoter region of hPim-2 (600 bp) contains two adjacent NF-kB-binding elements, two adjacent Oct-binding elements and an SP1 element by bioinformatic analysis. Studies have recently shown that the transcription factor Oct-2 and the B-cell specific Oct cofactor Bob-1 are overexpressed in certain large B-cell lymphomas, whereas increased expression of Bob-1 has also been observed in T-cell neoplasms. Shift assays (EMSA) analysis, using nuclear extracts from B-CLL cells and various fragments of hPim-2 promoter region used as probes, revealed that complexes containing an Oct elements were consistently heavier in B-CLL extracts compared with control B-cells. Accordingly, Oct-1, Oct-2 and Bob-1 protein levels were significantly higher in B-CLL compared to healthy extracts. Moreover, chromatin immunoprecipitation (Chip) assays confirmed that in-vivo Oct-1+2 and Bob-1 are indeed physically attached to the hPim-2 promoter, and that this interaction is significantly more intensive in B-CLL cells than in control B-cells. Furthermore, we have found in addition that the p52 isoform subunit of NF-kB predominates the interaction with the kB element in the hPim-2 promoter in B-CLL cells, as compared to the p50 isoform observed in control B-cells. To determine whether these interactions are transcriptionaly significant, we fused the luciferase reporter gene to various promoter fragments, and monitored luciferase expression in-vitro after incubation with either B-CLL or normal B-cell extracts. Luciferase expression was consistently higher when Oct element-containing fragment was incubated with B-CLL cell extracts. Together, these results suggest that the upregulation of hPim-2 in B-CLL is due to enhanced expression and transcriptional activity of the Oct-1+2 and Bob-1 complex and that it might synergistically act with the p52 containing NF-kB transcription factor.

miRNA Expression Profile of B-SLL Consistent with Normal Memory B Cells:BIC/miR–155 Specific Location in Proliferation Center.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2081-2081
Author(s):  
Miao Wang ◽  
Jan-Lukas Robertus ◽  
Lu-ping Tan ◽  
Geert Harms ◽  
Tjasso Blokzijl ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Expression Profile ◽  
Mirna Expression ◽  
Direct Sequencing ◽  
Memory B Cells ◽  
Lymphocytic Leukemia ◽  
Chain Gene ◽  
Mutation Status ◽  
Igh Genes

Abstract Introduction: B cell Chronic Lymphocytic Leukemia (B-CLL) is characterized by the accumulation of nonproliferating mature-appearing lymphocytes in the blood, marrow, lymph nodes, and spleen. B-CLL behaves like leukemia and is found mostly in the blood. The expression of ZAP-70 and mutation status of the immunoglobulin heavy-chain gene (IgH) can serve as prognostic markers in B-CLL. ZAP-70 positive cases usually present with unmutated IgH genes and have a bad prognosis, whereas ZAP-70 negative cases mostly present with mutated IgH genes and have good prognosis. Gene expression studies of B-CLL indicated that the profile of IgH mutated and unmutated cases are similar to normal memory B cells. Several studies showed that miRNAs play important roles in pathogenesis of B-CLL and some miRNAs correlate with the prognosis in B-CLL. B-SLL is considered to be the same disease entity as CLL, but this variant is found mostly in bone marrow and the lymphatic system. The most aggressive type of B-SLL is characterized by neoplastic cells that are more responsive to B-cell receptor signaling and are characterized by proliferation centers (PCs), a potentially important site of neoplastic cell stimulation. Until now, only a few reports have been published about the ZAP-70 expression and IgH mutation status and no data are available about the microRNA expression profile. Methods: 33 B-SLL cases were retrieved from the pathology files. ZAP-70 expression was analyzed by using immunohistochemistry. IgH mutation status was determined using PCR followed by direct sequencing. Cases with homology of ≥98% with germline sequences were considered as unmutated and cases with homologies &lt;98% as mutated. Levels of 15 miRNAs were determined by qRT-PCR using U6 as a housekeeping gene in 28 B-SLL cases with good quality RNA. As a control we also analyzed miRNA levels in normal naïve, GC and memory B cell subsets. RNA in-situ hybridization (ISH) was used to localize the most abundantly expressed miRNAs in B-SLL tissues. Results: 16 B-CLL cases were ZAP70+ with the vast majority of tumor cells staining positive and 17 were negative. Of the ZAP70+ cases 10 carried unmutated and 3 mutated IgH genes and 3 cases failed due to bad quality DNA. 14/17 ZAP-70- cases carried mutated IgH genes and 3 cases failed. miR-150, miR-21, miR-16, miR-92 and miR-155 were expressed at high levels in all B-SLL cases independent of the ZAP70 and IgH mutation status. The miRNA expression pattern in B-SLL was very similar to normal memory B cells. RNA-ISH for BIC, the primary transcript of miR-155, demonstrated the most abundant expression in the proliferation centers of B-SLL cases. Conclusion: In B-SLL there is significant correlation between ZAP-70 expression and IgH mutation status similar to B-CLL cases. miRNA expression levels in B-SLL did not correlate with ZAP-70 or IgH status. The overall expression profile is very similar to normal memory B cells. BIC/miR-155 expression is observed specifically in the proliferation center of B-SLL tissues.

scholarly journals Lipopolysaccharide-unresponsive mutant pre-B-cell lines blocked in NF-kappa B activation.

1990 ◽  
Vol 10 (1) ◽  
pp. 422-425 ◽  
Author(s):  
M Briskin ◽  
M Damore ◽  
R Law ◽  
G Lee ◽  
P W Kincade ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Chain Gene ◽  
Nf Kappa B ◽  
Light Chain Gene ◽  
Immunoglobulin Kappa ◽  
Variant Cell ◽  
Late Step ◽  
Mutant Lines

NF-kappa B activation is a crucial late step in the induction of immunoglobulin kappa light-chain gene expression in pre-B cells by lipopolysaccharide (LPS). We have analyzed NF-kappa B activation in three independent mutant lines of 70Z/3 pre-B cells which are unresponsive to LPS. All three variant cell lines failed to activate NF-kappa B when induced with LPS or the phorbol ester 12-O-tetradecanoylphorbol 13-acetate. However, all three cell lines contained functional NF-kappa B, as revealed by detergent treatment of cytoplasmic extracts. Moreover, cycloheximide induced limited activation of NF-kappa B comparable to that in wild-type 70Z/3 pre-B cells in two of the three variant lines. These results indicate that the mutations blocking kappa gene induction in these variant 70Z/3 pre-B-cell lines affect NF-kappa B activation.

scholarly journals Phospholipase Cγ2 Contributes to Light-Chain Gene Activation and Receptor Editing

2007 ◽  
Vol 27 (17) ◽  
pp. 5957-5967 ◽  
Author(s):  
Li Bai ◽  
Yuhong Chen ◽  
Yinghong He ◽  
Xuezhi Dai ◽  
Xueyan Lin ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Light Chain ◽  
Gene Activation ◽  
Chain Gene ◽  
Receptor Editing ◽  
Light Chain Gene ◽  
Transitional Type

ABSTRACT Phospholipase Cγ2 (PLCγ2) is critical for pre-B-cell receptor (pre-BCR) and BCR signaling. Current studies discovered that PLCγ2-deficient mice had reduced immunoglobulin λ (Igλ) light-chain usage throughout B-cell maturation stages, including transitional type 1 (T1), transitional type 2 (T2), and mature follicular B cells. The reduction of Igλ rearrangement by PLCγ2 deficiency was not due to specifically increased apoptosis or decreased proliferation of mutant Igλ+ B cells, as lack of PLCγ2 exerted a similar effect on apoptosis and proliferation of both Igλ+ and Igκ+ B cells. Moreover, PLCγ2-deficient IgHEL transgenic B cells exhibited an impairment of antigen-induced receptor editing among both the endogenous λ and κ loci in vitro and in vivo. Importantly, PLCγ2 deficiency impaired BCR-induced expression of IRF-4 and IRF-8, the two transcription factors critical for λ and κ light-chain rearrangements. Taken together, these data demonstrate that the PLCγ2 signaling pathway plays a role in activation of light-chain loci and contributes to receptor editing.

Lipopolysaccharide-unresponsive mutant pre-B-cell lines blocked in NF-kappa B activation

1990 ◽  
Vol 10 (1) ◽  
pp. 422-425
Author(s):  
M Briskin ◽  
M Damore ◽  
R Law ◽  
G Lee ◽  
P W Kincade ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Chain Gene ◽  
Nf Kappa B ◽  
Light Chain Gene ◽  
Immunoglobulin Kappa ◽  
Variant Cell ◽  
Late Step ◽  
Mutant Lines

NF-kappa B activation is a crucial late step in the induction of immunoglobulin kappa light-chain gene expression in pre-B cells by lipopolysaccharide (LPS). We have analyzed NF-kappa B activation in three independent mutant lines of 70Z/3 pre-B cells which are unresponsive to LPS. All three variant cell lines failed to activate NF-kappa B when induced with LPS or the phorbol ester 12-O-tetradecanoylphorbol 13-acetate. However, all three cell lines contained functional NF-kappa B, as revealed by detergent treatment of cytoplasmic extracts. Moreover, cycloheximide induced limited activation of NF-kappa B comparable to that in wild-type 70Z/3 pre-B cells in two of the three variant lines. These results indicate that the mutations blocking kappa gene induction in these variant 70Z/3 pre-B-cell lines affect NF-kappa B activation.

scholarly journals Early generated B1 B cells with restricted BCRs become chronic lymphocytic leukemia with continued c-Myc and low Bmf expression

2016 ◽  
Vol 213 (13) ◽  
pp. 3007-3024 ◽  
Author(s):  
Kyoko Hayakawa ◽  
Anthony M. Formica ◽  
Joni Brill-Dashoff ◽  
Susan A. Shinton ◽  
Daiju Ichikawa ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Subset ◽  
Lymphocytic Leukemia ◽  
Transgenic Expression ◽  
Bcr Signaling ◽  
B Cell Subsets ◽  
A Minor ◽  
B1 B Cells

In mice, generation of autoreactive CD5+ B cells occurs as a consequence of BCR signaling induced by (self)-ligand exposure from fetal/neonatal B-1 B cell development. A fraction of these cells self-renew and persist as a minor B1 B cell subset throughout life. Here, we show that transfer of early generated B1 B cells from Eμ-TCL1 transgenic mice resulted in chronic lymphocytic leukemia (CLL) with a biased repertoire, including stereotyped BCRs. Thus, B1 B cells bearing restricted BCRs can become CLL during aging. Increased anti-thymocyte/Thy-1 autoreactive (ATA) BCR cells in the B1 B cell subset by transgenic expression yielded spontaneous ATA B-CLL/lymphoma incidence, enhanced by TCL1 transgenesis. In contrast, ATA B-CLL did not develop from other B cell subsets, even when the identical ATA BCR was expressed on a Thy-1 low/null background. Thus, both a specific BCR and B1 B cell context were important for CLL progression. Neonatal B1 B cells and their CLL progeny in aged mice continued to express moderately up-regulated c-Myc and down-regulated proapoptotic Bmf, unlike most mature B cells in the adult. Thus, there is a genetic predisposition inherent in B-1 development generating restricted BCRs and self-renewal capacity, with both features contributing to potential for progression to CLL.

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