Despite recent advances in the treatment of multiple myeloma (MM), it remains an incurable disease potentially due to the presence of resistant myeloma cancer stem cells (MM-CSC). Although the presence of clonogenic cells in MM was described more than 30 years ago, the phenotype of MM-CSC is still a matter of debate, especially with respect to the expression of syndecan- 1 (CD138). Here, we demonstrate the presence of two subpopulations - CD138++ (95-99%) and CD138low (1-5%) - in eight MM cell lines. To find out possible stem-cell-like features, we have phenotypically, genomic and functionally characterized the two subpopulations. Our results show that the minor CD138low subpopulation is morphologically identical to the CD138++ fraction and does not represent a more immature B-cell compartment (with lack of CD19, CD20 and CD27 surface expression). Moreover, both subpopulations have similar gene expression and genomic profiles. Importantly, both CD138++ and CD138low subpopulations have similar sensitivity to bortezomib, melphalan and doxorubicin. Finally, serial engraftment in SCID mice shows that CD138++ as well as CD138low cells have self-renewal potential and they are also phenotypically interconvertible. Overall, our results differ from previously published data which attribute a B-cell phenotype to MM-CSC and urge the need to explore more reliable markers to discriminate true clonogenic myeloma cells.
Phenotypic, genomic and functional characterization reveals no differences between CD138++ and CD138low subpopulations in multiple myeloma cell lines.
Disease, Cell line
View SamplesAlthough new therapies have doubled the survival of multiple myeloma (MM) patients, this remains an incurable disease. It has been postulated that the so-called MM Cancer Stem Cells (MM-CSC) would be responsible for tumor initiation and relapse but their unequivocal identification remains unclear. Here, we investigated in a panel of MM cell lines the presence of CD20+ cells harboring a MM-CSC phenotype. Among the multiple cell lines investigated, only a small population of CD20dim+ cells (0.3%) in the RPMI-8226 cell line was found. CD20dim+ RPMI-8226 cells expressed the plasma cell markers CD38 and CD138 and were CD19-CD27-. Additionally, CD20dim+ RPMI-8226 cells did not exhibit stem-cell markers as shown by gene expression profiling and the aldehyde dehydrogenase (ALDH) assay. Moreover, we demonstrated that CD20dim+ RPMI-8226 cells are not essential for CB17-SCID mice engraftment and show lower self-renewal potential than the CD20- RPMI-8226 cells. These results do not support CD20+ expression for the identification of MM-CSC.
CD20 positive cells are undetectable in the majority of multiple myeloma cell lines and are not associated with a cancer stem cell phenotype.
No sample metadata fields
View SamplesMultiple Myeloma (MM) remains incurable, and new drugs with novel mechanisms of action are still needed. In this report, we have analyzed the action of Zalypsis, an alkaloid analogous to certain natural marine compounds, in MM. Zalypsis turned out to be the most potent antimyeloma agent we have tested so far, with IC50s from picomolar to low nanomolar ranges. It also showed remarkable ex vivo potency in plasma cells from patients and in MM cells in vivo xenografted in mice. Besides the induction of apoptosis and cell cycle arrest, Zalypsis provoked DNA double-strand-breaks (DSB), evidenced by an increase in phospho-Histone-H2AX and phospho-CHK2, followed by a striking overexpression of p53 in p53-wild type cell lines. In addition, in those cell lines in which p53 was mutated, Zalypsis also provoked DSB and induced cell death, although higher concentrations were required. Immunohistochemical studies in tumours also demonstrated Histone-H2AX phosphorylation and p53 overexpression. Gene expression profile studies were concordant with these results, revealing an important deregulation of genes involved in DNA-damage response. The potent in vitro and in vivo antimyeloma activity of Zalypsis uncovers the high sensitivity of tumour plasma cells to DSB, and strongly supports the use of this compound in MM patients.
Zalypsis: a novel marine-derived compound with potent antimyeloma activity that reveals high sensitivity of malignant plasma cells to DNA double-strand breaks.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The kinesin spindle protein inhibitor filanesib enhances the activity of pomalidomide and dexamethasone in multiple myeloma.
Specimen part, Cell line, Treatment
View SamplesKinesin spindle protein (KSP) inhibition is known to be an effective therapeutic approach in several malignancies. Filanesib (Arry-520), a KSP inhibitor, has demonstrated activity in heavily pretreated multiple myeloma (MM) patients. The aim of this work was to investigate the activity of filanesib in combination with an IMiDs plus dexamethasone backbone, and the mechanisms underlying the potential synergistic effect. Results: Filanesib showed in vitro and in vivo synergy with all IMiDs plus dexamethasone treatment, particularly with the pomalidomide combination (PDF). Importantly, the in vivo synergy observed in this combination was more evident in large, highly proliferative tumors, and it was shown to be mediated by impairment of mitosis transcriptional control, an increase in monopolar spindles, cell cycle arrest and the induction of apoptosis in cells in proliferative phases. In addition, PDF increased the activation of the proapoptotic protein Bax, which has been previously associated with sensitivity to filanesib, and could potentially be used as a predictive biomarker of response to this combination. Conclusions: Our results provide preclinical evidence for the potential benefit of the combination of filanesib with pomalidomide and dexamethasone and es-tablished the basis for a recently activated trial being conducted by the Spanish MM group investigating this combination in relapsed MM patients.
The kinesin spindle protein inhibitor filanesib enhances the activity of pomalidomide and dexamethasone in multiple myeloma.
Specimen part, Treatment
View SamplesKinesin spindle protein (KSP) inhibition is known to be an effective therapeutic approach in several malignancies. Filanesib (Arry-520), a KSP inhibitor, has demonstrated activity in heavily pretreated multiple myeloma (MM) patients. The aim of this work was to investigate the activity of filanesib in combination with an IMiDs plus dexamethasone backbone, and the mechanisms underlying the potential synergistic effect. Results: Filanesib showed in vitro and in vivo synergy with all IMiDs plus dexamethasone treatment, particularly with the pomalidomide combination (PDF). Importantly, the in vivo synergy observed in this combination was more evident in large, highly proliferative tumors, and it was shown to be mediated by impairment of mitosis transcriptional control, an increase in monopolar spindles, cell cycle arrest and the induction of apoptosis in cells in proliferative phases. In addition, PDF increased the activation of the proapoptotic protein Bax, which has been previously associated with sensitivity to filanesib, and could potentially be used as a predictive biomarker of response to this combination. Conclusions: Our results provide preclinical evidence for the potential benefit of the combination of filanesib with pomalidomide and dexamethasone and es-tablished the basis for a recently activated trial being conducted by the Spanish MM group investigating this combination in relapsed MM patients.
The kinesin spindle protein inhibitor filanesib enhances the activity of pomalidomide and dexamethasone in multiple myeloma.
Cell line, Treatment
View SamplesVestibular Schwannomas are benign neoplasms that arise from the vestibular nerve. The hallmark of these tumors is the biallelic inactivation of NF2. Transcriptomic alterations, such as the Nrg1/ErbB2 pathway, have been described in Schwannomas. Here, we have performed a whole transcriptomic analysis in 31 vestibular Schwannomas and 9 control nerves in the Affymetrix Gene 1.0ST platform, validated by quantitative Real-Time PCR using TaqMan Low Density Arrays. We performed a mutational analysis of NF2 by PCR/dHPLC and MLPA as well as a microsatellite marker analysis of the loss of heterozygosity of chromosome 22q. The microarray analysis showed that 1516 genes were deregulated, and 48 of the genes were validated by qRT-PCR. At least two genetic hits (allelic loss and/or gene mutation) in NF2 were found in 16 tumors, seven cases showed one hit and eight tumors showed no NF2 alteration. As conclusion, MET and associated genes such as ITGA4/B6, PLEXNB3/SEMA5 and CAV1 showed a clear deregulation in vestibular Schwannomas. In addition, androgen receptor (AR) downregulation may denote a hormonal effect or cause in this tumor. Furthermore, the osteopontin gene (SPP1), which is involved in Merlin protein degradation, was upregulated, which suggests that this mechanism may also exert a pivotal role in Schwannoma Merlin depletion. Finally, no major differences were found between tumors of different sizes, histological types or NF2 status, which suggests that at the mRNA level all Schwannomas, regardless of molecular and clinical characteristics, may share common features that can be used in the fight against them.
Microarray analysis of gene expression in vestibular schwannomas reveals SPP1/MET signaling pathway and androgen receptor deregulation.
No sample metadata fields
View SamplesThe transcriptomes of model organisms have been defined under specific laboratory growth conditions. The standard protocol for Caenorhabditis elegans growth and maintenance is 20ºC on an Escherichia coli diet. Temperatures ranging from 15ºC to 25ºC or feeding with other species of bacteria are considered physiological lab conditions, but the effect of these conditions on the worm transcriptome have not been well characterized. Here, we compare the global patterns of gene expression for the reference Caenorhabditis elegans strain (N2) grown at 15oC, 20oC, and 25oC on two different diets, Escherichia coli and Bacillus subtilis. When C. elegans were fed E. coli and the growth temperature was increased, we observed an enhancement of defense response pathways and down-regulation of genes associated with metabolic functions. However, when C. elegans were fed B. subtilis and the growth temperature was increased, the nematodes exhibited a decrease in defense response pathways and an enhancement of expression of genes associated with metabolic functions. Our results show that C. elegans undergo significant metabolic and defense response changes when the maintenance temperature fluctuates within the physiologically accepted experimental range and that the degree of pathogenicity of the bacterial diet can further alter the worm transcriptome. Overall design: C. elegans mRNA profiles at different temperatures and feeding in six samples, three replicates per sample. Deep sequencing in Illumina HiSeq2500.
Effect of the diet type and temperature on the <i>C. elegans</i> transcriptome.
Subject
View SamplesThe gastrointestinal (GI) tract can have significant impact on the regulation of the whole body metabolism and may contribute to the development of obesity and diabetes. To systemically elucidate the role of the GI tract in obesity, we performed a transcriptomic analyses in different parts of the GI tract of two obese mouse models: ob/ob and high-fat diet (HFD) fed mice. Compared to their lean controls, both obese mouse groups had significant amount of gene expression changes in the stomach (ob/ob: 959; HFD: 542), much more than the number of changes in the intestine. Despite the difference in genetic background, the two mouse models shared 296 similar gene expression changes in the stomach. Among those genes, some had known associations to obesity, diabetes and insulin resistance. In addition, the gene expression profile strongly suggested an increased gastric acid secretion in both obese mouse models, probably through an activation of the gastrin pathway. In conclusion, our data reveal a previously unknown dominant connection between the stomach and obesity.
Significant obesity-associated gene expression changes occur in the stomach but not intestines in obese mice.
Specimen part
View SamplesBACKGROUND: p53 is an important tumor suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated.
A limited role for p53 in modulating the immediate phenotype of Apc loss in the intestine.
Specimen part
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