Targeting Sphingosine Kinase Isoforms Effectively Reduces Growth and Survival of Neoplastic Mast Cells with D816V-KIT
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ABSTRACT:
PROVIDER: PRJNA435733 | ENA |
REPOSITORIES: ENA
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Project description:Mastocytosis is a disorder resulting from an abnormal mast cell (MC) accumulation in tissues that is often associated with the D816V mutation in KIT, the tyrosine kinase receptor for stem cell factor. Therapies available to treat aggressive presentations of mastocytosis are limited, thus exploration of novel pharmacological targets that reduce MC burden is desirable. Since increased generation of the lipid mediator sphingosine-1-phosphate (S1P) by sphingosine kinase (SPHK) has been linked to oncogenesis, we studied the involvement of the two SPHK isoforms (SPHK1 and SPHK2) in the regulation of neoplastic human MC growth. While SPHK2 inhibition prevented entry into the cell cycle in normal and neoplastic human MCs with minimal effect on cell survival, SPHK1 inhibition caused cell cycle arrest in G2/M and apoptosis, particularly in D816V-KIT MCs. This was mediated via activation of the DNA damage response cascade, including phosphorylation of the checkpoint kinase 2 (CHK2), CHK2-mediated CDC25c depletion and p53 activation. Combination treatment of SPHK inhibitors with KIT inhibitors showed greater growth inhibition of D816V-KIT MCs than either inhibitor alone. Furthermore, inhibition of SPHK reduced the number of malignant bone marrow MCs from patients with mastocytosis and the growth of D816V-KIT MCs in a xenograft mouse model. Our results reveal a role for SPHK isoforms in the regulation of growth and survival in normal and neoplastic MCs and suggest a regulatory function for SPHK1 in the DNA damage response in MCs with KIT mutations. The findings also suggest that targeting the SPHK/S1P axis may provide an alternative to tyrosine kinase inhibitors, alone or in combination, for treatment of aggressive mastocytosis and other hematological malignancies associated with the D816V-KIT mutation.
2018-03-30 | GSE111060 | GEO
Project description:Mastocytosis is a disorder resulting from an abnormal mast cell (MC) accumulation in tissues that is often associated with the D816V mutation in KIT, the tyrosine kinase receptor for stem cell factor. Therapies available to treat aggressive presentations of mastocytosis are limited, thus exploration of novel pharmacological targets that reduce MC burden is desirable. Since increased generation of the lipid mediator sphingosine-1-phosphate (S1P) by sphingosine kinase (SPHK) has been linked to oncogenesis, we studied the involvement of the two SPHK isoforms (SPHK1 and SPHK2) in the regulation of neoplastic human MC growth. While SPHK2 inhibition prevented entry into the cell cycle in normal and neoplastic human MCs with minimal effect on cell survival, SPHK1 inhibition caused cell cycle arrest in G2/M and apoptosis, particularly in D816V-KIT MCs. This was mediated via activation of the DNA damage response (DDR) cascade, including phosphorylation of the checkpoint kinase 2 (CHK2), CHK2-mediated M-phase inducer phosphatase 3 depletion, and p53 activation. Combination treatment of SPHK inhibitors with KIT inhibitors showed greater growth inhibition of D816V-KIT MCs than either inhibitor alone. Furthermore, inhibition of SPHK isoforms reduced the number of malignant bone marrow MCs from patients with mastocytosis and the growth of D816V-KIT MCs in a xenograft mouse model. Our results reveal a role for SPHK isoforms in the regulation of growth and survival in normal and neoplastic MCs and suggest a regulatory function for SPHK1 in the DDR in MCs with KIT mutations. The findings also suggest that targeting the SPHK/S1P axis may provide an alternative to tyrosine kinase inhibitors, alone or in combination, for the treatment of aggressive mastocytosis and other hematological malignancies associated with the D816V-KIT mutation.
| S-EPMC5883065 | biostudies-literature
Project description:Activating mutations in the receptor KIT promote the dysregulated proliferation of human mast cells (huMCs). The resulting neoplastic huMCs secrete extracellular vesicles (EVs) that can transfer oncogenic KIT among other cargo into recipient cells. Despite potential contributions to diseases, KIT-containing EVs have not been thoroughly investigated. Here, we isolated KIT-EV subpopulations released by neoplastic huMCs using an immunocapture approach that selectively isolates EVs containing KIT in its proper topology. Proteomic profiling was performed on KIT-containing EVs compared to KIT-depleted EV populations, and on KIT-EVs that are microvesicle- and exosome-like.
2023-03-10 | PXD033889 | Pride
Project description:The HMC-1.1 and 1.2 human mast cell (huMC) lines are often employed in the study of attributes of neoplastic huMCs as found in patients with mastocytosis and their sensitivity to interventional drugs in vitro and in vivo. Both cell lines express mutated and constitutively active KIT, an essential growth factor receptor for huMC survival and function, with one KIT mutation in HMC-1.1 cells (V560G-KIT) and two in HMC-1.2 cells (D816V-KIT and V560G-KIT). D816V-KIT is commonly associated with systemic mastocytosis, while V560G-KIT appears more frequently in other human neoplasms. The functional consequences of the coexisting KIT mutations in HMC-1.2 cells are unknown. We used CRISPR/Cas9 engineering to reverse the V560G-KIT mutation in HMC-1.2 cells, resulting in a subline (HMC-1.3) with a single monoallelic D816V-KIT mutation. Transcriptome analyses of differentially expressed genes in HMC1.3 compared to HMC-1.2 predicted reduced activity in pathways involved in survival, cell-to-cell adhesion, and neoplasia, with differences in expression of molecular components and cell surface markers. Consistently, subcutaneous inoculation of HMC-1.3 into mice produced significantly smaller tumors than HMC-1.2 cells, and in colony assays, HMC-1.3 formed less numerous and smaller colonies than HMC-1.2 cells. However, in liquid culture conditions, the growth of HMC-1.2 and HMC-1.3 cells was comparable, albeit increased compared to HMC-1.1 cells. Phosphorylation levels of ERK1/2, AKT and STAT5, representing pathways associated with constitutive oncogenic KIT signaling, were also similar between HMC-1.2 and HMC-1.3 cells but increased compared to HMC-1.1 cells. Despite these similarities, survival of HMC-1.3 cells in liquid culture was diminished in response to various pharmacological inhibitors, including tyrosine kinase inhibitors used clinically for treatment of advanced systemic mastocytosis, and JAK2 and BCL2 inhibitors, making HMC-1.3 more susceptible to these drugs than HMC-1.2 cells. Our study reveals that the additional V560G-KIT variant in HMC-1.2 cells modifies transcriptional programs induced by D816V-KIT, confers a survival advantage, alters sensitivity to interventional drugs, and increases the tumorigenicity, suggesting that engineered huMCs with a single D816V-KIT variant may represent an improved preclinical model for mastocytosis.
2023-03-09 | GSE216446 | GEO
Project description:We investigated the metabolic regulation of mast cell (MC) functions to control them. MCs are sentinels of the immune system with functions involved not only in host defense but also, if not properly controlled, in MC disorders such as systemic mastocytosis (SM). We identified N-acetyl-D-glucosamine (GlcNAc or NAG) as both a circulating biomarker for SM severity and an oncometabolite that promotes uncontrolled degranulation and proliferation of MCs expressing the Kit kinase domain mutant allele, D816V, that is both an oncogene and characterizes patients with SM. Given the known role of GlcNAc-related protein glycosylation in modifying factors involved in epigenetic regulation of gene expression and the effects of GlcNAc on neoplastic MCs effector functions, we asked whether the increased susceptibility of KIT D816V MCs to GlcNAc was due to chromatin state changes.
2023-04-20 | GSE149106 | GEO
Project description:To decipher molecular targets responsible for c-Kit mutant D816V mediated hematopoietic malignancy, we employed whole genome microarray expression profiling as a discovery platform to identify important gene targets downstream of c-Kit mutant D816V expressing cells compared to wild-type c-Kit.
2016-04-30 | GSE76355 | GEO
Project description:Kit is a receptor-type tyrosine kinase found on the plasma membrane. It can transform mast cells through activating mutations. Here, we show that a mutant Kit from neoplastic mast cells from mice, Kit(D814Y), is permanently active and allows cells to proliferate autonomously. It does so by activating two signalling pathways from different intracellular compartments. Mutant Kit from the cell surface accumulates on endolysosomes through clathrin-mediated endocytosis, which requires Kit's kinase activity. Kit(D814Y) is constitutively associated with phosphatidylinositol 3-kinase, but the complex activates Akt only on the cytoplasmic surface of endolysosomes. It resists destruction because it is under-ubiquitinated. Kit(D814Y) also appears in the endoplasmic reticulum soon after biosynthesis, and there, can activate STAT5 aberrantly. These mechanisms of oncogenic signalling are also seen in rat and human mast cell leukemia cells. Thus, oncogenic Kit signalling occurs from different intracellular compartments, and the mutation acts by altering Kit trafficking as well as activation.
| S-EPMC4284665 | biostudies-literature
Project description:Mutations in the c-kit gene occur in the vast majority of mastocytosis. In adult patients as well as in the cell line derived from mast cell neoplasms, the mutations occur almost exclusively at amino acid 816 within the kinase domain of KIT. Among the downstream effectors of KIT signaling, STAT3 and STAT5 have been shown to be critical for cell proliferation elicited by the KIT-Asp(816) mutant protein. However, little is known about the mechanisms of activation of STAT proteins. In this study, we identify and clarify the contribution of various STAT kinases in two widely used neoplastic mast cell lines, P815 and HMC-1. We show that STAT1, -3, and -5 proteins are activated downstream of the KIT-Asp(816) mutant. All three STAT proteins are located in the nucleus and are phosphorylated on serine residues. KIT-Asp(816) mutant can directly phosphorylate STATs on the activation-specific tyrosine residues in vitro. However, within cells, SRC family kinases and JAKs diversely contribute to tyrosine phosphorylation of STAT proteins downstream of the KIT mutant. Using a panel of inhibitors, we provide evidence for the implication or exclusion of serine/threonine kinases as responsible for serine phosphorylation of STAT1, -3, and -5 in the two cell lines. Finally, we show that only STAT5 is transcriptionally active in these cells. This suggests that the contribution of STAT1 and STAT3 downstream of KIT mutant is independent of their transcription factor function.
| S-EPMC3057865 | biostudies-other
Project description:Transcriptional profiling of 28 hpf zebrafish transgenic expressing human KIT-D816V mutant gene versus wild-type embryos was performed. The aim of this experiment was to determine the expression changes caused by expression of KIT-D816V oncogene. This transgenic zebrafish represents a model of systemic mastocytosis with many features of this disease present in adults, but no very clear phenotypes in embryos. Thus, we attempted to determine if there are certain expression changes, which can be used as molecular features of active KIT expressed in these embryos. Two-condition experiment, Tg(actb2:KIT-D816V) versus wild-type(AB), 4 replicate experiments with a dye-swap each time
2014-02-03 | E-GEOD-54613 | biostudies-arrayexpress
Project description:The D816V-mutated variant of Kit triggers multiple signaling pathways and is considered essential for malignant transformation in mast cell (MC) neoplasms. We here describe that constitutive activation of the Stat5-PI3K-Akt-cascade controls neoplastic MC development. Retrovirally transduced active Stat5 (cS5(F)) was found to trigger PI3K and Akt activation, and to transform murine bone marrow progenitors into tissue-infiltrating MCs. Primary neoplastic Kit D816V(+) MCs in patients with mastocytosis also displayed activated Stat5, which was found to localize to the cytoplasm and to form a signaling complex with PI3K, with consecutive Akt activation. Finally, the knock-down of either Stat5 or Akt activity resulted in growth inhibition of neoplastic Kit D816V(+) MCs. These data suggest that a downstream Stat5-PI3K-Akt signaling cascade is essential for Kit D816V-mediated growth and survival of neoplastic MCs.
| S-EPMC2532813 | biostudies-other