Targeting Sphingosine Kinase Isoforms Effectively Reduces Growth and Survival of Neoplastic Mast Cells with D816V-KIT
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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: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: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:Sphingolipids enforce homeostatic cell growth in eukaryotes1,2. Phytosphingosine triggers an adaptive growth arrest in heat-stressed yeast while ceramide and its precursor/product sphingosine function as tumor suppressors in mammalian cells. Consistent with this, the constrained cyclic analogs of sphingosine FTY720 and SH-BC-893 limit tumor growth in multiple pre-clinical cancer models3,4. However, the protein targets that mediate the anti-neoplastic effects of sphingosine-like molecules remain poorly defined. Here we show that natural and synthetic sphingosine-like compounds engage the protein phosphatase 2A (PP2A) scaffolding subunit PPP2R1A and the structurally related karyopherins importin-β1 (KPNB1), transportin-1 (TNPO1), importin-5 (IPO5), and importin-7 (IPO7). While sphingosine-like molecules were known to activate PP2A3–6, binding to importins was unexpected. PP2A activation limits nutrient access through effects on endolysosomal trafficking3,7–9, but also triggers the proteasomal degradation of anabolic transcription factors like MYC and the androgen receptor (AR)10,11. Importins are required for oncogenic transcription factors to enter the nucleus and engage their target genes. By activating PP2A and inhibiting importins in parallel, sphingosine-like compounds robustly inhibited prostate cancer drivers YAP, JUN, MYC and the AR as well as other proteins involved in proliferation, metabolism, and protein translation. Sphingosine itself also induced conformational changes in PPP2R1A and KPNB1 and blocked IPO7- and KPNB1-dependent nuclear import. Interestingly, ceramide did not engage these protein targets suggesting that ceramide and sphingosine promote homeostatic cell growth through different mechanisms. These results provide biological insights into the anti-neoplastic actions of sphingosine and related molecules and highlight a possible path towards cancer therapeutics that engage PP2A and importins in parallel, simultaneously targeting multiple difficult-to-drug oncoproteins.
2025-05-14 | PXD036429 | Pride
Project description:The CD117 mast/stem cell growth factor receptor tyrosine kinase (KIT) is critical for haematopoiesis, melanogenesis, and stem cell maintenance. KIT is commonly activated by mutation in cancers including acute myeloid leukaemia, melanoma, and gastrointestinal stromal tumours (GISTs). The kinase and the juxtamembrane domains of KIT are mutation hotspots; with the kinase domain mutation D816V common in leukaemia, and the juxtamembrane domain mutation V560G common in GISTs. Given the importance of mutant KIT signalling in cancer, we have conducted a proteomic and phosphoproteomic analysis of D816V- and V560G-KIT mutations, using an FDCP1 isogenic cell line model.
2025-06-19 | PXD043783 | 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:Objective is to identify microRNAs regulated by KIT signaling in mast cells. miRNA profiles of murine bone marrow derived mast cells with and without SCF treatment were compared. In addition, miRNA profiles of the P815 mutant KIT cell line with and without the KIT inhibitor, imatinib, were compared. We identified miRNAs that were differentially regulated by KIT signals. Two systems were used to identify microRNAs regulated by KIT. RNA was collected from primary murine bone marrow derived mast cells (BMMC) treated and not treated with KIT ligand (SCF). In addition, RNA was harvested from the P815 (activating KIT mutation positive) cell line treated and not treated with the KIT inhibitor, imatinib. Samples were harvested after 24 hours of treatment
2011-01-25 | E-GEOD-26783 | biostudies-arrayexpress
Project description:Objective is to identify microRNAs regulated by KIT signaling in mast cells. miRNA profiles of murine bone marrow derived mast cells with and without SCF treatment were compared. In addition, miRNA profiles of the P815 mutant KIT cell line with and without the KIT inhibitor, imatinib, were compared. We identified miRNAs that were differentially regulated by KIT signals.
2011-01-25 | GSE26783 | GEO
Project description:Mast cells (MC) represent a population of hematopoietic cells with a key role in innate and adaptive immunity and are well known for their detrimental role in allergic responses. Yet, MC occur in low abundance which hampers their detailed molecular analysis. Here, we capitalized on the potential of induced pluripotent stem (iPS) cells to give rise to all cells of the body and established a robust protocol for human iPS cell differentiation towards MC. Relying on a panel of systemic mastocytosis (SM) patient-specific iPS cell lines carrying the KIT D816V mutation, we generated functional MC that recapitulate SM disease features: increased number of MC, abnormal maturation kinetics and activated phenotype, CD2 and CD30 surface expression and a transcriptional signature characterized by upregulated expression of innate and inflammatory response genes. Therefore, human iPS cell-derived MC are a reliable and close-to-human tool for disease modeling and pharmacological screening to explore novel MC therapeutics.
2023-04-05 | GSE223883 | GEO