Human embryonic stem cells (hESCs) replicate by the process of self-renewal, whilst maintaining their pluripotency. Understanding the pathways involved in the regulation of this self-renewal process will assist in developing fully-defined conditions for the proliferation of hESCS required for therapeutic applications. We previously demonstrated a role for Sphingosine-1-phosphate (S1P) in the survival and proliferation of hESCs. The present study investigates further key signalling pathways and the downstream targets of S1P.
Sphingosine-1-phosphate mediates transcriptional regulation of key targets associated with survival, proliferation, and pluripotency in human embryonic stem cells.
No sample metadata fieldsView Samples
Myeloma bone disease is characterized by tremendous bone destruction with suppressed bone formation. IL-3 is a multifunctional cytokine that increases myeloma cell growth and osteoclast proliferation while inhibiting osteoblast differentiation. While IL-3 appears to be an attractive therapeutic target for myeloma, attempts at targeting IL-3 have been unsuccessful due to IL-3s effects on normal hematopoiesis. Thus identification of IL-3s downstream effects in MMBD is important for effective targeting of this cytokine in MM. Here we demonstrated that treatment of myeloma patient CD14+ bone marrow monocyte / macrophages with IL-3 induces high levels of Activin A (ActA), a pluripotent TGF- superfamily member that, like IL-3, modulates MMBD by enhancing osteoclastogenesis and inhibiting osteoblasts. We show that IL-3 induced osteoclastogenesis is mediated by ActA and is RANKL independent. Additionally, IL-3 induced ActA secretion is greatest early in osteoclastogenesis and ActA acts early in osteoclastogenesis. Therefore we suggest that therapies targeting ActA production should block IL-3s effects in myeloma bone disease.
Bone marrow monocyte-/macrophage-derived activin A mediates the osteoclastogenic effect of IL-3 in multiple myeloma.
Specimen part, Disease, Disease stage, TreatmentView Samples
GEP class prediction in association with CI-FISH (42 candidate genes) and patient MRD stratification
Linking genomic lesions with minimal residual disease improves prognostic stratification in children with T-cell acute lymphoblastic leukaemia.
Specimen part, Disease, Disease stageView Samples
A rare complication of multiple myeloma is a secondary extramedullary involvement, and the skin is one of the possible sites, due to the physiological homing of plasma cells (PCs) into the skin. The article reports a case of a relapsed refractory MM patient, who developed a cutaneous localization after 16 months from the diagnosis under Bortezomib treatment without a leukemic phase. Patient was refractory to Bortezomib. We analyzed the gene expression profiles, the immunophenotypic and immunohistochemistry profiles of MM cells across the course of the disease at the bone marrow and skin localization. Data obtained were further expanded by an immunohistochemistry analysis on selected molecules in a large cohort of MM patients with cutaneous localization. In particular we focused on the expression of chemokines and chemokine receptors involved in the PC skin homing.
Cutaneous localization in multiple myeloma in the context of bortezomib-based treatment: how do myeloma cells escape from the bone marrow to the skin?
Sex, Age, Specimen part, Subject, TimeView Samples
In multiple myeloma (MM), hypoxia-inducible transcription factor-1 (HIF-1) is overexpressed in the MM cells of the hypoxic bone marrow (BM) microenvironment. Herein, we explored in MM cells the in vitro and in vivo effects of persistent HIF-1 inhibition by expression of a lentivirus shRNA pool on proliferation, survival and transcriptional and pro-angiogenic profiles. Among the significantly modulated genes (326 and 361 genes in hypoxic and normoxic condition, respectively), we found that HIF-1 inhibition in the human myeloma cell line JJN3 downregulates the pro-angiogenic molecules VEGF, IL8, IL10, CCL2, CCL5, and MMP9. Interestingly, several pro-osteoclastogenic cytokines were also inhibited, such as IL-7 and CCL3/MIP-1. The effect of HIF-1 inhibition was assessed in vivo in NOD/SCID mice both in subcutaneous and intratibial models, indicating in either case a dramatic reduction of weight and volume of the tumor burden as a consequence of HIF-1 knockdown. Moreover, a significant reduction of the number of vessels per field and VEGF immunostaining were observed. Finally, in the intra-tibial experiments, HIF-1 inhibition significantly blocks JJN3-induced bone destruction. Overall, our data indicate that HIF-1 suppression in MM cells significantly blocks MM-induced angiogenesis and reduces both tumor burden and bone destruction in vivo, strongly indicating HIF-1 as an emerging therapeutic target in MM.
Hypoxia-inducible factor (HIF)-1α suppression in myeloma cells blocks tumoral growth in vivo inhibiting angiogenesis and bone destruction.
Specimen part, Cell lineView Samples
Bone marrow monocytes are primarily committed to osteoclast formation. It is, however, unknown whether potential primary alterations are specifically present in bone marrow monocytes from patients with multiple myeloma, smoldering myeloma or monoclonal gammopathy of undetermined significance. We analyzed the immunophenotypic and transcriptional profiles of bone marrow CD14+ monocytes in a cohort of patients with different types of monoclonal gammopathies to identify alterations involved in myeloma-enhanced osteoclastogenesis. The number of bone marrow CD14+CD16+ cells was higher in patients with active myeloma than in those with smoldering myeloma or monoclonal gammopathy of undetermined significance. Interestingly, sorted bone marrow CD14+CD16+ cells from myeloma patients were more pro-osteoclastogenic than CD14+CD16-cells in cultures ex vivo Moreover, transcriptional analysis demonstrated that bone marrow CD14+ cells from patients with multiple myeloma (but neither monoclonal gammopathy of undetermined significance nor smoldering myeloma) significantly upregulated genes involved in osteoclast formation, including IL21RIL21R mRNA over-expression by bone marrow CD14+ cells was independent of the presence of interleukin-21. Consistently, interleukin-21 production by T cells as well as levels of interleukin-21 in the bone marrow were not significantly different among monoclonal gammopathies. Thereafter, we showed that IL21R over-expression in CD14+ cells increased osteoclast formation. Consistently, interleukin-21 receptor signaling inhibition by Janex 1 suppressed osteoclast differentiation from bone marrow CD14+ cells of myeloma patients. Our results indicate that bone marrow monocytes from multiple myeloma patients show distinct features compared to those from patients with indolent monoclonal gammopathies, supporting the role of IL21R over-expression by bone marrow CD14+ cells in enhanced osteoclast formation.
<i>IL21R</i> expressing CD14<sup>+</sup>CD16<sup>+</sup> monocytes expand in multiple myeloma patients leading to increased osteoclasts.
Age, Specimen partView Samples
Enhanced secondary Ab responses are a vital component of adaptive immunity, yet little is understood about the intrinsic and extrinsic regulators of nave and memory B cells that results in differences in their responses to Ag. Microarray analysis, together with surface and intracellular phenotyping, revealed that memory B cells have increased expression of members of the TNF receptor, SLAM, B7 and Bcl2 families, as well as the TLR-related molecule CD180 (RP105). Accordingly, memory B cells exhibited enhanced survival, proliferation and Ig secretion, as well as entered division more rapidly than nave B cells in response to both T-dependent and T-independent stimuli. Furthermore, both IgM and isotype switched memory B cells, but not nave B cells, co-stimulated CD4+ T cells in vitro through a mechanism dependent on their constitutive expression of CD80 and CD86. This study demonstrates that upregulation of genes involved in activation, co-stimulation and survival provides memory B cells with a unique ability to produce enhanced immune responses and contributes to the maintenance of the memory B cell pool.
Resting human memory B cells are intrinsically programmed for enhanced survival and responsiveness to diverse stimuli compared to naive B cells.
Specimen partView Samples
Galectin-1 (Gal-1) is a lectin, involved in several processes related to cancer, including immunosuppression, angiogenesis, hypoxia, and metastases. Actually, the Gal-1 expression profile in multiple myeloma (MM) and its pathophysiological role in MMinduced angiogenesis and tumoral growth is unknown. Firstly, we found that Gal-1 was expressed by malignant plasma cells in MM patients and that its expression was up-regulated upon hypoxic treatment (1% of O2). Moreover the stable knock-down of Hypoxia Inducible Factor-1 (HIF-1) in MM cells significantly downregulated Gal-1 expression. Thereafter, we performed Gal-1 inhibition by lentivirus shRNA anti-Gal-1 in human myeloma cell lines (HMCLs) showing that its suppression did not affect cell proliferation and survival but modified their transcriptional profiles either in hypoxia or hypoxia condition. Interestingly pro-angiogenic genes including MMP9 and CCL2 were downregulated and those anti-angiogenic SEMA3A and CXCL10 were up-regulated by Gal-1 inhibition in MM cells. Data were also validated by Real time PCR and at protein level. Consistently we found that Gal-1 suppression in MM cells significantly decreased their pro-angiogenic proprieties by an in vitro assay. These evidences were confirmed in mice injected either subcutaneously or intratibially with HMCLs carrying a stable infection with shRNA anti-inhibition of Gal-1 or with the control vector cell line. Gal-1 suppression in both models showed a significant reduction in the tumoral burden and microvascular density compared to the control mice. Moreover, Gal-1 suppression induced smaller lytic lesions on x-ray in the intratibially model. Overall, our data indicate that Gal-1 is a new potential therapeutic target in MM.
Galectin-1 suppression delineates a new strategy to inhibit myeloma-induced angiogenesis and tumoral growth in vivo.
Specimen part, Cell lineView Samples
Cells were isolated from healthy human donors (n=2). Unstimulated cells. Cells were stained with CD4, CD45RA, CCR7 and CXCR7. Using flow cytometry, 4 CD4+ T cell populations were sorted: (1) Nave (CD45RA+CCR7+CXCR5-), (2) Central memory (CD45RA-CCR7+CXCR5-), (3) Effector memory (CD45RA-CCR7-CXCR5-) and (4) CXCR5+ cells (CD45RA-CCR7-CXCR5+)
CXCR5 expressing human central memory CD4 T cells and their relevance for humoral immune responses.
Specimen partView Samples
The accumulation of unfolded proteins in the lumen of the endoplasmic reticulum (ER) causes stress and induces the unfolded protein response (UPR) which is characterised in part by the transcriptional induction of genes involved in assisting protein folding. Translational responses to ER stress have been less well described and here we report on a genome-wide analysis of translational regulation in the response to the ER stress-inducing agent dithiothreitol (DTT) in Saccharomyces cerevisiae. Although the observed polysome profiles were similar under control and ER stress conditions microarray analysis identified transcipt-specific translational regulation. Genes with functions in ribosomal biogenesis and assembly were translationally repressed under ER stress. In contrast mRNAs for known UPR genes, including the UPR transcription factor HAC1, the ER-oxidoreductase ERO1 and the ER-associated protein degradation (ERAD) gene DER1 were enriched in polysomal fractions under ER stress conditions. In addition, we show that splicing of HAC1 mRNA is required for efficient ribosomal loading and that Gcn2p is required for normal HAC1 splicing, so shedding light on the role of this protein kinase in the UPR pathway.
Transcript-specific translational regulation in the unfolded protein response of Saccharomyces cerevisiae.
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