scholarly journals LEF-1 is a prosurvival factor in chronic lymphocytic leukemia and is expressed in the preleukemic state of monoclonal B-cell lymphocytosis

Blood ◽  
2010 ◽  
Vol 116 (16) ◽  
pp. 2975-2983 ◽  
Author(s):  
Albert Gutierrez ◽  
Renee C. Tschumper ◽  
Xiaosheng Wu ◽  
Tait D. Shanafelt ◽  
Jeanette Eckel-Passow ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Wnt Signaling ◽  
B Cell ◽  
Signaling Pathway ◽  
Wnt Pathway ◽  
Wnt Signaling Pathway ◽  
Lymphocytic Leukemia ◽  
Luciferase Reporter ◽  
Aberrant Expression

Abstract The canonical Wnt signaling pathway is pathogenic in a variety of cancers. We previously identified aberrant expression of the Wnt pathway transcription factor and target gene lymphoid enhancer binding factor-1 (LEF1) in chronic lymphocytic leukemia (CLL). This suggested that the Wnt signaling pathway has a role in the biology of CLL. In this study, we performed a Wnt pathway analysis using gene expression profiling and identified aberrant regulation of Wnt pathway target genes, ligands, and signaling members in CLL cells. Furthermore, we identified aberrant protein expression of LEF-1 specifically in CLL but not in normal mature B-cell subsets or after B-cell activation. Using the T cell–specific transcription factor/LEF (TCF/LEF) dual luciferase reporter assay, we demonstrated constitutive Wnt pathway activation in CLL, although the pathway was inactive in normal peripheral B cells. Importantly, LEF-1 knockdown decreased CLL B-cell survival. We also identified LEF-1 expression in CD19+/CD5+ cells obtained from patients with monoclonal B-cell lymphocytosis, suggesting a role for LEF-1 early in CLL leukemogenesis. This study has identified the constitutive activation and prosurvival function of LEF-1 and the Wnt pathway in CLL and uncovered a possible role for these factors in the preleukemic state of monoclonal B-cell lymphocytosis.

scholarly journals Activation of the Wnt signaling pathway in chronic lymphocytic leukemia

2004 ◽  
Vol 101 (9) ◽  
pp. 3118-3123 ◽  
Author(s):  
D. Lu ◽  
Y. Zhao ◽  
R. Tawatao ◽  
H. B. Cottam ◽  
M. Sen ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Lymphocytic Leukemia

scholarly journals Cirmtuzumab Inhibits Non-Canonical Wnt Signaling without Enhancing Canonical Wnt/β-Catenin Signaling in Chronic Lymphocytic Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2652-2652
Author(s):  
Han Zhang ◽  
Suping Zhang ◽  
Emanuela M. Ghia ◽  
Michael Y. Choi ◽  
Jieyu Zhang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Chronic Lymphocytic Leukemia ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Lymphocytic Leukemia ◽  
Canonical Wnt Signaling ◽  
Gene Set Enrichment ◽  
Canonical Wnt ◽  
Cell Stem Cell

Abstract ROR1 is a receptor tyrosine kinase-like orphan receptor for Wnt5a that is expressed by cells during embryogenesis and by the neoplastic cells of a variety of cancers, including chronic lymphocytic leukemia (CLL). ROR1 can induce activation of β-catenin-independent non-canonical Wnt-signaling. Studies reveal a cross-talk between the non-canonical Wnt-signaling pathway and the β-catenin-dependent canonical Wnt-signaling pathway, which we previously found was also activated in CLL (Lu D, et al, PNAS 101:31118-3123, 2004). Prior studies indicated that silencing a related Wnt5a receptor, ROR2, could augment canonical Wnt-signaling induced by Wnt3a. In this study, we examined whether genetic silencing of ROR1 or inhibition of ROR1-signaling also could influence canonical Wnt signaling. To inhibit ROR1 signaling we used the humanized anti-ROR1 mAb cirmtuzumab, which is being evaluated in patients with CLL (Choi MY, et al, Cell Stem Cell, 22:951, 2018). Surprisingly, we found that CRISPR/Cas9 deletion of ROR1 in 293T cells also could enhance the capacity of Wnt3a to activate canonical Wnt-signaling, albeit to a lesser extent than CRISPR/Cas9 deletion of ROR2; conversely, re-introduction of ROR1 into ROR1-deleted 293T cells suppressed Wnt3a-induced activation of canonical Wnt-signaling. In contrast, treatment of wildtype 293T cells with cirmtuzumab did not enhance Wnt3a-induced activation of canonical Wnt-signaling, but nonetheless suppressed ROR1-dependent non-canonical signaling induced by Wnt5a. We examined the influence of ROR1 on canonical Wnt-signaling in CLL. First, we examined whether the relative expression of ROR1 influenced the relative levels of genes induced by activation of the canonical Wnt-signaling pathway. Gene set enrichment analysis (GSEA) of gene-expression data on CLL cells of different patients (n=448, GSE13204) revealed that CLL cells with low-level expression of ROR1 (ROR1Low) did not have increased levels of genes induced by activation of canonical Wnt-signaling relative to those noted in CLL cells with high-level expression of ROR1 (ROR1Hi). Nonetheless, ROR1Hi CLL cells did have increased levels of genes induced by activation of non-canonical Wnt signaling compared to ROR1Low CLL cells. As in 293T cells, siRNA-mediated knockdown of ROR1 in ROR1Hi CLL cells could enhance the capacity of Wnt3a to increase the levels of genes induced by canonical Wnt-signaling (e.g. MYC, CCND1). However, treatment of the same CLL cells with cirmtuzumab did not enhance the levels of such genes in response to Wnt3a, even at concentrations that exceeded those required to inhibit Wnt5a-induced ROR1-dependent non-canonical Wnt-signaling. We examined whether these findings also applied to CLL cells treated with cirmtuzumab in vivo. For this, we performed gene-set enrichment analyses on the transcriptomes of CLL cells collected from patients before and after treatment with cirmtuzumab in a recently completed phase I clinical trial (Choi MY, et al, Cell Stem Cell, 22:951, 2018). Although treatment with cirmtuzumab repressed expression of genes induced by activation of non-canonical Wnt signaling, we did not observe changes in the levels of genes induced by activation of the canonical Wnt signaling pathway. Collectively, this study demonstrates that cirmtuzumab can inhibit non-canonical Wnt signaling without enhancing canonical Wnt signaling in CLL, in contrast to what we observed in CLL cells silenced for ROR1. As such, treatment with cirmtuzumab may represent a more selective approach to suppressing non-canonical Wnt5a signaling than strategies aimed at genetic down-modulation or silencing of ROR1. Disclosures Choi: Rigel: Consultancy; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Gilead: Speakers Bureau; AbbVie, Inc: Consultancy, Speakers Bureau; Genentech: Speakers Bureau.

Aberrant expression of B-lymphocyte stimulator by B chronic lymphocytic leukemia cells: a mechanism for survival

Blood ◽  
2002 ◽  
Vol 100 (8) ◽  
pp. 2973-2979 ◽  
Author(s):  
Anne J. Novak ◽  
Richard J. Bram ◽  
Neil E. Kay ◽  
Diane F. Jelinek
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
B Lymphocyte ◽  
Leukemic Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Aberrant Expression ◽  
B Lymphocyte Stimulator

B-cell chronic lymphocytic leukemia (B-CLL) is defined by the accumulation of CD5+ B cells in the periphery and bone marrow. This disease is not characterized by highly proliferative cells but rather by the presence of leukemic cells with significant resistance to apoptosis and, therefore, prolonged survival. B-lymphocyte stimulator (BLyS) is a newly identified tumor necrosis factor (TNF) family member shown to be critical for maintenance of normal B-cell development and homeostasis and it shares significant homology with another TNF superfamily member, APRIL. The striking effects of BLyS on normal B-cell maintenance and survival raises the possibility that it may be involved in pathogenesis and maintenance of hematologic malignancies, including B-CLL. In this study, we investigated the status of APRIL and BLyS expression, as well as their receptors, in this disease. All B-CLL patient cells studied expressed one or more of 3 known receptors for BLyS; however, the pattern of expression was variable. In addition, we demonstrate for the first time that B-CLL cells from a subset of patients aberrantly express BLyS and APRIL mRNA, whereas these molecules were not detectable in normal B cells. Furthermore, we provide in vitro evidence that BLyS protects B-CLL cells from apoptosis and enhances cell survival. Because these molecules are key regulators of B-cell homeostasis and tumor progression, leukemic cell autocrine expression of BLyS and APRIL may be playing an important role in the pathogenesis of this disease.

scholarly journals GPX8 is transcriptionally regulated by FOXC1 and promotes the growth of gastric cancer cells through activating the Wnt signaling pathway

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Hong Chen ◽  
Lu Xu ◽  
Zhi-li Shan ◽  
Shu Chen ◽  
Hao Hu
Keyword(s):  
Gastric Cancer ◽  
Transcription Factor ◽  
Western Blot ◽  
Wnt Signaling ◽  
Cancer Cells ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Migration And Invasion ◽  
Gastric Cancer Cells ◽  
Cancer Tissues

Abstract Background Glutathione Peroxidase 8 (GPX8) as a member of the glutathione peroxidase (GPx) family plays an important role in anti-oxidation. Besides, dysregulation of GPX8 has been found in gastric cancer, but its detailed molecular mechanism in gastric cancer has not been reported. Methods Our study detected the expression of GPX8 in gastric cancer tissues and cell lines using immunohistochemistry (IHC), western blot and qRT-PCR, and determined the effect of GPX8 on gastric cancer cells using CCK-8, colony formation, transwell migration and invasion assays. Besides, the effect of GPX8 on the Wnt signaling pathway was determined by western blot. Furthermore, the transcription factor of GPX8 was identified by bioinformatics methods, dual luciferase reporter and chromatin immunoprecipitation (CHIP) assays. In addition, the effect of GPX8 on tumor formation was measured by IHC and western blot. Results The over-expression of GPX8 was observed in gastric cancer tissues and cells, which facilitated the proliferation, migration and invasion of gastric cancer cells as well as the tumor growth. GPX8 knockdown effectively inhibited the growth of gastric cancer cells and tumors. Moreover, GPX8 could activate the Wnt signaling pathway to promote the cellular proliferation, migration and invasion through. Furthermore, FOXC1 was identified as a transcription factor of GPX8 and mediated GPX8 expression to affect cell development processes. Conclusions These findings contribute to understanding the molecular mechanism of GPX8 in gastric cancer. Additionally, GPX8 can be a potential biomarker for gastric cancer therapy.

scholarly journals LncRNA HCG11 promotes proliferation and migration in gastric cancer via targeting miR-1276/CTNNB1 and activating Wnt signaling pathway

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Hua Zhang ◽  
Haitao Huang ◽  
Xiaomei Xu ◽  
Haiying Wang ◽  
Jianxiang Wang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Function Analysis ◽  
Wnt Signaling Pathway ◽  
Tumor Formation ◽  
Tumor Promoter ◽  
Luciferase Reporter ◽  
And Migration ◽  
Proliferation And Migration

Abstract Background Gastric cancer (GC) is one common cancer which occurs in the stomach leading to high mortality around the world. Long non-coding RNAs (lncRNAs) were found overexpressed or silenced in the occurrence and progression of multiple cancers including GC. Method The gene expression level in GC tissues and cells were analyzed by RT-qPCR. CCK-8, colony formation, flow cytometry and transwell assays were performed for the function analysis of HLA complex group 11 (HCG11). The mechanism study for HCG11 was conducted using RIP, RNA pull down and luciferase reporter assays. Results HCG11 was discovered highly expressed in GC tissues and cells. Depletion experiments were used to evaluate HCG11 silence on cell proliferation, migration and apoptosis. Moreover, Wnt signaling pathway was found as a tumor promoter in GC. RIP assay, RNA pull down assay and luciferase reporter assay were performed to illustrate the relationship of HCG11, miR-1276 and CTNNB1. Rescue assays revealed that HCG11/miR-1276/CTNNB1 axis regulated the incidence and development of GC. Tumor formation in mice proved that HCG11 was negatively correlated with miR-1276 and had positively correlation with CTNNB1. Conclusion Overall, HCG11 accelerated proliferation and migration in GC through miR-1276/CTNNB1 and Wnt signaling pathway, revealing that HCG11 could be a brand new target for GC.

scholarly journals The Microphthalmia-Associated Transcription Factor Mitf Interacts with β-Catenin To Determine Target Gene Expression

2006 ◽  
Vol 26 (23) ◽  
pp. 8914-8927 ◽  
Author(s):  
Alexander Schepsky ◽  
Katja Bruser ◽  
Gunnar J. Gunnarsson ◽  
Jane Goodall ◽  
Jón H. Hallsson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Critical Role ◽  
Wnt Signaling Pathway ◽  
Feedback Mechanism ◽  
Canonical Wnt Signaling ◽  
Melanocyte Stem Cells ◽  
Canonical Wnt

ABSTRACT Commitment to the melanocyte lineage is characterized by the onset of expression of the microphthalmia-associated transcription factor (Mitf). This transcription factor plays a fundamental role in melanocyte development and maintenance and seems to be crucial for the survival of malignant melanocytes. Furthermore, Mitf has been shown to be involved in cell cycle regulation and to play important functions in self-renewal and maintenance of melanocyte stem cells. Although little is known about how Mitf regulates these various processes, one possibility is that Mitf interacts with other regulators. Here we show that Mitf can interact directly with β-catenin, the key mediator of the canonical Wnt signaling pathway. The Wnt signaling pathway plays a critical role in melanocyte development and is intimately involved in triggering melanocyte stem cell proliferation. Significantly, constitutive activation of this pathway is a feature of a number of cancers including malignant melanoma. Here we show that Mitf can redirect β-catenin transcriptional activity away from canonical Wnt signaling-regulated genes toward Mitf-specific target promoters to activate transcription. Thus, by a feedback mechanism, Mitf can diversify the output of canonical Wnt signaling to enhance the repertoire of genes regulated by β-catenin. Our results reveal a novel mechanism by which Wnt signaling and β-catenin activate gene expression, with significant implications for our understanding of both melanocyte development and melanoma.

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.

Different Activation of WNT Signaling Pathway in B-Cell and T-Cell Acute Leukemias.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4317-4317
Author(s):  
Muge Sayitoglu ◽  
Ozden Hatirnaz ◽  
Yucel Erbilgin ◽  
Fatmahan Atalar ◽  
Ugur Ozbek
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Wnt Signaling ◽  
B Cell ◽  
Signaling Pathway ◽  
Peripheral Blood ◽  
Lymphoblastic Leukemia ◽  
Wnt Signaling Pathway ◽  
Hematopoietic Cells ◽  
Expression Levels

Abstract WNT signaling pathway proteins function as hematopoietic growth factors and regulate proliferation in normal T-cell and B-cell development. Recent experimental evidence demonstrated that oncogenic transformation in leukemias of both lymphoid and myeloid lineages is dependent on WNT signaling. Not much is known about activation of WNT signaling pathway, its ligands and receptors in hematopoiesis and leukemia pathogenesis. To define its role in leukemia, we aimed to determine mRNA levels of the critical members of WNT pathway (WNT5A, WNT10B, FZ5, β catenin, APC, TCF-1 and LEF-1) by using quantitative real time PCR in acute lymphoblastic leukemia (ALL) patients (T-cell n=42, B-cell n=46 and pre B-cell n=30) and normal hematopoietic cells (bone marrow n=6, peripheral blood n=10, and CD19+ cells from peripheral blood). These genes expressed varying levels in B-cells, preB-cells and T-cells. In the B-cell leukemia patients, WNT5A was expressed notably (OR=58.05 CI 95% 1.63–1219.55, p>0,001). WNT5A directs Ca++ dependent signaling by PKC and a G protein dependent manner which is an alternative pathway for beta-catenin mediated signaling. Also LEF-1 levels were higher in B-ALL patients and APC expression was down regulated when compared to normal tissue (OR=18.81 CI 95% 0.34–5703, p>0.001 and OR=0.212 CI 95% 0.006–8.816, p=0.001, respectively). It is known that LEF-1 blocks APC mediated β catenin nuclear export and activates transcription of various transforming genes, including cyclin, D1, c-myc, MMP7, and LEF-1 itself. WNT5A or WNT10B proteins were not found to be up regulated in preB-ALL whereas APC and LEF-1 gene expressions were increased compared to normal hematopoietic cells (OR=32.97 CI 95% 0.27–1281, 38 p>0.001 and OR=5.57 CI 95% 0.28–89.51, p=0.01, respectively). We found increased TCF-1 expression (7.4 fold) without any β catenin accumulation in T-ALL patients. It is known that TCF-1 in absence of β catenin functions as a tumor suppressor gene. WNT5A, APC and LEF-1 gene expression levels were also different between T-cell, B-cell and preB cell ALL cases. WNT5A expression had the highest levels in B-ALL compared to T-ALL cases, whereas the highest APC expression levels were observed in preB and T-ALL patients. Also LEF-1 expression levels were significantly different between preB and T-cell ALL patients. Taken together these results indicate that WNT signaling genes have abnormal expression and are active in acute lymphoblastic leukemia. This data suggests different WNT activation mechanisms exist in the leukemic transformation in different hematopoietic cells.

scholarly journals Wnt/β-Catenin/Tcf Signaling Induces the Transcription of Axin2, a Negative Regulator of the Signaling Pathway

2002 ◽  
Vol 22 (4) ◽  
pp. 1172-1183 ◽  
Author(s):  
Eek-hoon Jho ◽  
Tong Zhang ◽  
Claire Domon ◽  
Choun-Ki Joo ◽  
Jean-Noel Freund ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Pathway ◽  
Genomic Sequence ◽  
Wnt Signaling Pathway ◽  
Genomic Region ◽  
Negative Regulator ◽  
Mobility Shift ◽  
Specific Expression

ABSTRACT Axin2/Conductin/Axil and its ortholog Axin are negative regulators of the Wnt signaling pathway, which promote the phosphorylation and degradation of β-catenin. While Axin is expressed ubiquitously, Axin2 mRNA was seen in a restricted pattern during mouse embryogenesis and organogenesis. Because many sites of Axin2 expression overlapped with those of several Wnt genes, we tested whether Axin2 was induced by Wnt signaling. Endogenous Axin2 mRNA and protein expression could be rapidly induced by activation of the Wnt pathway, and Axin2 reporter constructs, containing a 5.6-kb DNA fragment including the promoter and first intron, were also induced. This genomic region contains eight Tcf/LEF consensus binding sites, five of which are located within longer, highly conserved noncoding sequences. The mutation or deletion of these Tcf/LEF sites greatly diminished induction by β-catenin, and mutation of the Tcf/LEF site T2 abolished protein binding in an electrophoretic mobility shift assay. These results strongly suggest that Axin2 is a direct target of the Wnt pathway, mediated through Tcf/LEF factors. The 5.6-kb genomic sequence was sufficient to direct the tissue-specific expression of d2EGFP in transgenic embryos, consistent with a role for the Tcf/LEF sites and surrounding conserved sequences in the in vivo expression pattern of Axin2. Our results suggest that Axin2 participates in a negative feedback loop, which could serve to limit the duration or intensity of a Wnt-initiated signal.

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