Somatically acquired JAK1 mutations in adult acute lymphoblastic leukemia. J Exp Med

Dipartimento di Biologia Cellulare e Neuroscienze, Istituto Superiore di Sanità, Rome, 00161, Italy.
Journal of Experimental Medicine (Impact Factor: 12.52). 05/2008; 205(4):751-8. DOI: 10.1084/jem.20072182
Source: PubMed


Aberrant signal transduction contributes substantially to leukemogenesis. The Janus kinase 1 (JAK1) gene encodes a cytoplasmic tyrosine kinase that noncovalently associates with a variety of cytokine receptors and plays a nonredundant role in lymphoid cell precursor proliferation, survival, and differentiation. We report that somatic mutations in JAK1 occur in individuals with acute lymphoblastic leukemia (ALL). JAK1 mutations were more prevalent among adult subjects with the T cell precursor ALL, where they accounted for 18% of cases, and were associated with advanced age at diagnosis, poor response to therapy, and overall prognosis. All mutations were missense, and some were predicted to destabilize interdomain interactions controlling the activity of the kinase. Three mutations that were studied promoted JAK1 gain of function and conferred interleukin (IL)-3-independent growth in Ba/F3 cells and/or IL-9-independent resistance to dexamethasone-induced apoptosis in T cell lymphoma BW5147 cells. Such effects were associated with variably enhanced activation of multiple downstream signaling pathways. Leukemic cells with mutated JAK1 alleles shared a gene expression signature characterized by transcriptional up-regulation of genes positively controlled by JAK signaling. Our findings implicate dysregulated JAK1 function in ALL, particularly of T cell origin, and point to this kinase as a target for the development of novel antileukemic drugs.

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Available from: Lorenzo Stella
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    • "It needs to be established, however, to what extent JAK/STAT activation is driving disease in these groups. For example, in T-cell acute lymphoblastic leukaemia activating mutations in JAK1 have been identified in a substantial proportion of patients, where they are thought to promote survival of malignant cells but JAK mutations are not thought to be the primary driver of disease (Flex et al, 2008). "
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    ABSTRACT: Aberrant activation of intracellular signalling pathways confers malignant properties on cancer cells. Targeting intracellular signalling pathways has been a productive strategy for drug development, with several drugs acting on signalling pathways already in use and more continually being developed. The JAK/STAT signalling pathway provides an example of this paradigm in haematological malignancies, with the identification of JAK2 mutations in myeloproliferative neoplasms leading to the development of specific clinically effective JAK2 inhibitors, such as ruxolitinib. It is now clear that many solid tumours also show activation of JAK/STAT signalling. In this review, we focus on the role of JAK/STAT signalling in solid tumours, examining the molecular mechanisms that cause inappropriate pathway activation and their cellular consequences. We also discuss the degree to which activated JAK/STAT signalling contributes to oncogenesis. Studies showing the effect of activation of JAK/STAT signalling upon prognosis in several tumour types are summarised. Finally, we discuss the prospects for treating solid tumours using strategies targeting JAK/STAT signalling, including what can be learned from haematological malignancies and the extent to which results in solid tumours might be expected to differ.British Journal of Cancer advance online publication 7 July 2015; doi:10.1038/bjc.2015.233
    Full-text · Article · Jul 2015 · British Journal of Cancer
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    • "These results are also in agreement with gene expression profiling, which documented a low PTPRC expression (data not shown). As PTPRC and JAK1 positive cells are reported to be sensitive to JAK1/2 inhibitors (Flex et al, 2008; Shilling et al, 2010; Porcu et al, 2012), we investigated the in vitro sensitivity of the blasts cryopreserved at diagnosis to ruxolitinib (Selleck Chemicals, Houston, TX, USA). As shown in Fig 1D, treatment with 1 lmol/l of ruxolitinib induced a marked reduction in leukaemic cell viability "

    Preview · Article · Apr 2015 · British Journal of Haematology
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    • "When wild-type 2C4 cells were injected into zebrafish, they show metastasis after 24 hours, which is sustained over a 5 day period (Figure 6b). The derivative U4C cells, which are genetically deficient for JAK1 [29,30], failed to spread throughout the fish body and showed virtually no invasion in vitro (Figure 6a). In fact, not a single cell was seen in the fish body, but sustained cell masses were seen in the perivitelline space demonstrating the persistence of viable cells in the fish over this period. "
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    ABSTRACT: In vivo metastasis assays have traditionally been performed in mice, but the process is inefficient and costly. However, since zebrafish do not develop an adaptive immune system until 14 days post-fertilization, human cancer cells can survive and metastasize when transplanted into zebrafish larvae. Despite isolated reports, there has been no systematic evaluation of the robustness of this system to date. Individual cell lines were stained with CM-Dil and injected into the perivitelline space of 2-day old zebrafish larvae. After 2-4 days fish were imaged using confocal microscopy and the number of metastatic cells was determined using Fiji software. To determine whether zebrafish can faithfully report metastatic potential in human cancer cells, we injected a series of cells with different metastatic potential into the perivitelline space of 2 day old embryos. Using cells from breast, prostate, colon and pancreas we demonstrated that the degree of cell metastasis in fish is proportional to their invasion potential in vitro. Highly metastatic cells such as MDA231, DU145, SW620 and ASPC-1 are seen in the vasculature and throughout the body of the fish after only 24--48 hours. Importantly, cells that are not invasive in vitro such as T47D, LNCaP and HT29 do not metastasize in fish. Inactivation of JAK1/2 in fibrosarcoma cells leads to loss of invasion in vitro and metastasis in vivo, and in zebrafish these cells show limited spread throughout the zebrafish body compared with the highly metastatic parental cells. Further, knockdown of WASF3 in DU145 cells which leads to loss of invasion in vitro and metastasis in vivo also results in suppression of metastasis in zebrafish. In a cancer progression model involving normal MCF10A breast epithelial cells, the degree of invasion/metastasis in vitro and in mice is mirrored in zebrafish. Using a modified version of Fiji software, it is possible to quantify individual metastatic cells in the transparent larvae to correlate with invasion potential. We also demonstrate, using lung cancers, that the zebrafish model can evaluate the metastatic ability of cancer cells isolated from primary tumors. The zebrafish model described here offers a rapid, robust, and inexpensive means of evaluating the metastatic potential of human cancer cells. Using this model it is possible to critically evaluate whether genetic manipulation of signaling pathways affects metastasis and whether primary tumors contain metastatic cells.
    Full-text · Article · Oct 2013 · BMC Cancer
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