Growth Suppression of Pre-T Acute Lymphoblastic Leukemia Cells by Inhibition of Notch Signaling

Departments of Pathology, Brigham and Women's Hospital, Harvard Medical School. Department of Adult Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Molecular and Cellular Biology (Impact Factor: 4.78). 02/2003; 23(2):655-64. DOI: 10.1128/MCB.23.2.655-664.2003
Source: PubMed


Constitutive NOTCH signaling in lymphoid progenitors promotes the development of immature T-cell lymphoblastic neoplasms (T-ALLs).
Although it is clear that Notch signaling can initiate leukemogenesis, it has not previously been established whether continued
NOTCH signaling is required to maintain T-ALL growth. We demonstrate here that the blockade of Notch signaling at two independent
steps suppresses the growth and survival of NOTCH1-transformed T-ALL cells. First, inhibitors of presenilin specifically induce
growth suppression and apoptosis of a murine T-ALL cell line that requires presenilin-dependent proteolysis of the Notch receptor
in order for its intracellular domain to translocate to the nucleus. Second, a 62-amino-acid peptide derived from a NOTCH
coactivator, Mastermind-like-1 (MAML1), forms a transcriptionally inert nuclear complex with NOTCH1 and CSL and specifically
inhibits the growth of both murine and human NOTCH1-transformed T-ALLs. These studies show that continued growth and survival
of NOTCH1-transformed lymphoid cell lines require nuclear access and transcriptional coactivator recruitment by NOTCH1 and
identify at least two steps in the Notch signaling pathway as potential targets for chemotherapeutic intervention.

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    • "Similarly, mutations in FBXW7, a gene that encodes an ubiquitin ligase, mimic the effect of NOTCH1 PEST deletions thus increasing the stability of ICN1. Several studies strongly support the development of NOTCH1 inhibitors for targeted cancer therapy, particularly for T-ALL, where recurrent NOTCH1 mutations are common and cancer dependency has been well established (16–21). For example, several reports have shown that transgenic expression of ICN1 leads to the rapid development of aggressive T-cell leukemia/lymphomas (7, 20). "
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    ABSTRACT: Acute lymphoblastic leukemia is the most common malignancy in children. Although it is now curable in 80-90% of cases, patients with T-cell acute lymphoblastic leukemia (T-ALL) experience a higher frequency of induction failure and early relapse. Despite aggressive treatment approaches, including transplantation and new salvage regimens, most children with relapsed T-ALL will not be cured. As such, we are in need of new targeted therapies for the disease. Recent advances in the molecular characterization of T-ALL have uncovered a number of new therapeutic targets. This review will summarize recent advancements in the study of inhibiting the NOTCH1, PI3K-AKT, and Cyclin D3:CDK4/6 pathways as therapeutic strategies for T-ALL. We will focus on pre-clinical studies supporting the testing of small-molecule inhibitors targeting these proteins and the rationale of combination therapies. Moreover, epigenetic approaches to modulate T-ALL are rapidly emerging. Here, we will discuss the data supporting the role of bromodomain and extra-terminal bromodomain inhibitors in human T-ALL.
    Frontiers in Oncology 07/2014; 4:170. DOI:10.3389/fonc.2014.00170
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    • "Rbpj, or together with DNMAML, a dominant-negative form of MAML which blocks the Notch-dependent Rbpj funciton40 was transfected into Ishikawa cells. Rbpj-transfected cells showed significantly suppressed estrogenic responses, as evidenced by the downregulation of ERα target genes (IGF1 and cMyc)41 following E2 treatment (Figure 4F); these cells also showed decreased cell proliferation during in vitro culture after Rbpj transfection (Figure 4G). "
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    ABSTRACT: Coordinated uterine-embryonic axis formation and decidual remodeling are hallmarks of mammalian post-implantation embryo development. Embryonic-uterine orientation is determined at initial implantation and synchronized with decidual development. However, the molecular mechanisms controlling these events remain elusive despite its discovery a long time ago. In the present study, we found that uterine-specific deletion of Rbpj, the nuclear transducer of Notch signaling, resulted in abnormal embryonic-uterine orientation and decidual patterning at post-implantation stages, leading to substantial embryo loss. We further revealed that prior to embryo attachment, Rbpj confers on-time uterine lumen shape transformation via physically interacting with uterine estrogen receptor (ERα) in a Notch pathway-independent manner, which is essential for the initial establishment of embryo orientation in alignment with uterine axis. While at post-implantation stages, Rbpj directly regulates the expression of uterine matrix metalloproteinase in a Notch pathway-dependent manner, which is required for normal post-implantation decidual remodeling. These results demonstrate that uterine Rbpj is essential for normal embryo development via instructing the initial embryonic-uterine orientation and ensuring normal decidual patterning in a stage-specific manner. Our data also substantiate the concept that normal mammalian embryonic-uterine orientation requires proper guidance from developmentally controlled uterine signaling.Cell Research advance online publication 27 June 2014; doi:10.1038/cr.2014.82.
    Cell Research 06/2014; DOI:10.1038/cr.2014.82 · 12.41 Impact Factor
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    • "Another target for blocking Notch signaling in malignant T cell leukemia is RBP-J that mediates the effects of Notch1 mutants on downstream gene expression. Expression of a dominant-negative MAML1 (DN-MAML1) in T-ALL cell lines has been shown to antagonize Notch1 activation [14,15]. Subsequently, Moellering et al. designed a stable α-helical peptide derived from MAML1 (SAHM1) based on the structure of DN-MAML1. "
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    ABSTRACT: Background Aberrantly activated Notch signaling has been found in more than 50% of patients with T-cell acute lymphoblastic leukemia (T-ALL). Current strategies that employ γ-secretase inhibitors (GSIs) to target Notch activation have not been successful. Many limitations, such as non-Notch specificity, dose-limiting gastrointestinal toxicity and GSI resistance, have prompted an urgent need for more effective Notch signaling inhibitors for T-ALL treatment. Human four-and-a-half LIM domain protein 1C (FHL1C) (KyoT2 in mice) has been demonstrated to suppress Notch activation in vitro, suggesting that FHL1C may be new candidate target in T-ALL therapy. However, the role of FHL1C in T-ALL cells remained unclear. Methods Using RT-PCR, we amplified full-length human FHL1C, and constructed full-length and various truncated forms of FHL1C. Using cell transfection, flow cytometry, transmission electron microscope, real-time RT-PCR, and Western blotting, we found that overexpression of FHL1C induced apoptosis of Jurkat cells. By using a reporter assay and Annexin-V staining, the minimal functional sequence of FHL1C inhibiting RBP-J-mediated Notch transactivation and inducing cell apoptosis was identified. Using real-time PCR and Western blotting, we explored the possible molecular mechanism of FHL1C-induced apoptosis. All data were statistically analyzed with the SPSS version 12.0 software. Results In Jurkat cells derived from a Notch1-associated T-ALL cell line insensitive to GSI treatment, we observed that overexpression of FHL1C, which is down-regulated in T-ALL patients, strongly induced apoptosis. Furthermore, we verified that FHL1C-induced apoptosis depended on the RBP-J-binding motif at the C-terminus of FHL1C. Using various truncated forms of FHL1C, we found that the RBP-J-binding motif of FHL1C had almost the same effect as full-length FHL1C on the induction of apoptosis, suggesting that the minimal functional sequence in the RBP-J-binding motif of FHL1C might be a new drug candidate for T-ALL treatment. We also explored the molecular mechanism of FHL1C overexpression-induced apoptosis, which suppressed downstream target genes such as Hes1 and c-Myc and key signaling pathways such as PI3K/AKT and NF-κB of Notch signaling involved in T-ALL progression. Conclusions Our study has revealed that FHL1C overexpression induces Jurkat cell apoptosis. This finding may provide new insights in designing new Notch inhibitors based on FHL1C to treat T-ALL.
    BMC Cancer 06/2014; 14(1):463. DOI:10.1186/1471-2407-14-463 · 3.36 Impact Factor
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