Multiple myeloma is largely incurable, despite development of therapies that target myeloma cell-intrinsic pathways. Disease relapse is thought to originate from dormant myeloma cells, localized in specialized niches, which resist therapy and re-populate the tumor. However, little is known about the niche, and how it exerts cell-extrinsic control over myeloma cell dormancy and re-activation. In this study we track individual myeloma cells by intravital imaging as they colonize the endosteal niche, enter a dormant state and subsequently become activated to form colonies. We demonstrate that dormancy is a reversible state which is switched on by engagement with bone lining cells or osteoblasts, and switched off by osteoclasts remodeling the endosteal niche. Dormant myeloma cells are resistant to chemotherapy targeting dividing cells. The demonstration that the endosteal niche is pivotal in controlling myeloma cell dormancy highlights the potential for targeting cell-extrinsic mechanisms to overcome cell-intrinsic drug resistance and prevent disease relapse.
Osteoclasts control reactivation of dormant myeloma cells by remodelling the endosteal niche.
Specimen part
View SamplesHT29 cells were transsfected with siRNA (siHX), which is targeting the human endogeous retrovirus HERV-HX. Cells were harvested 72 h after transfection and knock-down of HERV-HX was evaluated by quantitative RT-PCR.
No associated publication
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Enduring epigenetic landmarks define the cancer microenvironment.
Sex, Specimen part, Subject
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No associated publication
Specimen part, Treatment
View SamplesAscertain the effects of disease-causing gene mutations on the differentiation status of human nave CD4+ T cells in the setting of primary immunodeficiencies. Thus, do CD4+ T cells isolated according to a nave surface phenotype (ie CD4+CD45RA+CCR7+) from healthy donors exhibit a similar gene expression profile as phenotpyically-matched cells isolated from individuals with defined primary immunodeficiencies caused by specific monogenic mutations.
Unique and shared signaling pathways cooperate to regulate the differentiation of human CD4+ T cells into distinct effector subsets.
Specimen part
View SamplesWhile adipogenesis is controlled by a cascade of transcription factors, the global gene expression profiles in the early phase of adipogenesis are not well defined. Using microarray analysis of gene expression in 3T3-L1 cells we have identified evidence for the activity of 2568 genes during the early phase of adipocyte differentiation. One of these, ISL1, was of interest since its expression was markedly upregulated at 1 h after initiation of differentiation with a subsequent rapid decline. Overexpression of ISL1 at early times during adipocyte differentiation, but not at later times, was found to profoundly inhibit differentiation. This was accompanied by moderate down-regulation of PPARg levels, substantial down-regulation of PPARg downstream genes and down-regulation of BMP4 levels in preadipocytes. Readdition of BMP4 overcame the inhibitory effect of ISL1 on PPARg but not aP2 expression, a downstream gene of PPARg; and BMP4 also partially rescued ISL1 inhibition of adipogenesis, an effect which is additive with rosiglitazone. These results suggest that ISL1 is intimately involved in early regulation of adipogenesis, modulating PPARg expression and activity via BMP4-dependent and -independent mechanisms. Our time course gene expression survey sets the stage for further studies to explore other early and immediate regulators.
ISL1 regulates peroxisome proliferator-activated receptor γ activation and early adipogenesis via bone morphogenetic protein 4-dependent and -independent mechanisms.
Cell line, Treatment, Time
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No associated publication
Specimen part, Cell line
View SamplesThe aim of this study was to characterize expression profiles of visceral and subcutaneous adipose tissue in children. Adipose tissue samples were collected from children having elective surgery (n=71, [54 boys], 6.0 +- 4.3 years). Affymetrix microarrays (n=20) were performed to characterize the functional profile and identify genes of interest in adipose tissue. Visceral adipose tissue had an overrepresentation of Gene Ontology themes related to immune and inflammatory responses and subcutaneous adipose tissue had an overrepresentation of themes related to adipocyte growth and development. Likewise, qPCR performed in the whole cohort showed a 30-fold increase in haptoglobin (P < 0.005), 7-fold increase in IL-10 (P < 0.001), 8-fold decrease in VEGF (P < 0.01) and a 28-fold decrease in TBOX15 (P < 0.001) in visceral compared to subcutaneous adipose tissue.The inflammatory pattern in visceral adipose tissue may represent an early stage of the adverse effects of this depot, and combined with chronic obesity, may contribute to increased metabolic and cardiovascular risk.
An early inflammatory gene profile in visceral adipose tissue in children.
Sex, Specimen part
View SamplesThe NF-B pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-B signaling is well studied, there is little information on the divergent non-canonical NF-B pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-B inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-B components p100 to p52, and accumulation of RelB. Tumor necrosis factor (TNF) and receptor activator of NF-B ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-B transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity.
Nuclear factor κB-inducing kinase activation as a mechanism of pancreatic β cell failure in obesity.
Specimen part, Treatment
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ELF5 suppresses estrogen sensitivity and underpins the acquisition of antiestrogen resistance in luminal breast cancer.
Cell line, Treatment, Time
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