Stromal alterations in patients with MGUS, smoldering myeloma and multiple myeloma

The hallmark of multiple myeloma (MM) is a clonal plasma cell infiltration in the bone marrow accompanied by myelosuppression and osteolysis. Premalignant stages like monoclonal gammopathy of undetermined significance (MGUS) and asymptomatic stages like smoldering myeloma (SMM) can progress to multiple myeloma (MM). Mesenchymal stromal cells (MSC) are an integral component of the bone marrow microenvironment and play an important role for osteoblast differentiation and hematopoietic support. While stromal alterations have been reported in MM contributing to hematopoietic insufficiency and osteolysis, it is not clear whether alterations in MSC already occur in MGUS or SMM. In this study we analyzed MSC from MGUS, SMM and MM towards their properties and functionality and performed mRNA sequencing to find underlying molecular signatures in different disease stages. A high number of senescent cells and a reduced osteogenic differentiation capacity and hematopoietic support was already present in MGUS MSC. As shown by RNA sequencing there was a broad spectrum of differentially expressed genes including genes of the BMP/TGF-signaling pathway, detected already in MGUS and that clearly increases in SMM and MM patients. Our data may help to block these signaling pathways in the future to hinder progression to multiple myeloma.

Allogeneic hematopoietic stem cell transplantation and pre-transplant strategies in patients with NPM1-mutated acute myeloid leukemia: a single center experience

Patients with acute myeloid leukemia (AML) and nucleophosmin 1 gene mutations (NPM1mut) show a favorable prognosis with chemotherapy (CT) in the absence of negative prognostic genetic abnormalities. Between 2008 and 2021 64 patients with NPM1mutAML received alloHSCT because of additional adverse prognostic factors (1st line), inadequate response to or relapse during or after CT (2nd line). To expand the evidence in alloTX in NPM1mut AML, clinical and molecular data were retrospectively analyzed with respect to pre-transplant strategies and outcome. Patients with minimal residual disease negative (MRD-) CR at transplant had better 2-y-PFS and 2-y-OS (77% and 88%) than patients with minimal residual disease positive (MRD+) CR (41% and 71%) or patients with active disease (AD) at transplant (20% and 52%). The 2nd line patients with relapse after completing CT responded well to high dose cytarabine based salvage chemotherapy (salvage CT) in contrast to patients relapsing while still on CT (90% vs 20%, P = 0.0170). 2-y-PFS and 2-y-OS was 86% in patients who achieved a 2nd MRD- CR pre alloHSCT. Outcome in NPM1mutAML depends on disease burden at alloHSCT. Time and type of relapse in relation to CT are predictive for response to salvage CT.

Acute myeloid leukemia-induced functional inhibition of healthy CD34+ hematopoietic stem and progenitor cells

Acute myeloid leukemia (AML) is characterized by an expansion of leukemic cells and a simultaneous reduction of normal hematopoietic precursors in the bone marrow (BM) resulting in hematopoietic insufficiency, but the underlying mechanisms are poorly understood in humans. Assuming that leukemic cells functionally inhibit healthy CD34+ hematopoietic stem and progenitor cells (HSPC) via humoral factors, we exposed healthy BM-derived CD34+ HSPC to cell-free supernatants derived from AML cell lines as well as from 24 newly diagnosed AML patients. Exposure to AML-derived supernatants significantly inhibited proliferation, cell cycling, colony formation, and differentiation of healthy CD34+ HSPC. RNA sequencing of healthy CD34+ HSPC after exposure to leukemic conditions revealed a specific signature of genes related to proliferation, cell-cycle regulation, and differentiation, thereby reflecting their functional inhibition on a molecular level. Experiments with paired patient samples showed that these inhibitory effects are markedly related to the immunomagnetically enriched CD34+ leukemic cell population. Using PCR, ELISA, and RNA sequencing, we detected overexpression of TGFβ1 in leukemic cells on the transcriptional and protein level and, correspondingly, a molecular signature related to TGFβ1 signaling in healthy CD34+ HSPC. This inhibitory effect of TGFβ1 on healthy hematopoiesis was functionally corrobated and could be pharmacologically reverted by SD208, an inhibitor of TGFβ receptor 1 signaling. Overall, these data indicate that leukemic cells induce functional inhibition of healthy CD34+ HSPC, at least in part, through TGFβ1, suggesting that blockage of this pathway may improve hematopoiesis in AML.

Prognostic impact of peripheral blood WT1-mRNA expression in patients with MDS

Few reports suggested a prognostic impact of Wilms'Tumor-1 (WT1)-mRNA overexpression in MDS, but translation into clinical routine was hampered by limited patients numbers, differing sample sources, non-standardized methods/cut-offs. To evaluate whether WT1-mRNA expression yields additional prognostic information, we measured peripheral blood (PB) WT1-mRNA expression in 94 MDS using a standardized assay offering a validated cut-off to discriminate between normal and WT1-mRNA overexpression. Overall, 54 patients (57%) showed WT1-mRNA overexpression, while 40 patients (43%) had normal WT1-mRNA expression. This enabled discrimination between MDS and both healthy controls and non-MDS cytopenias. Furthermore, WT1-mRNA expression correlated with WHO 2016 subcategories and IPSS-R as indicated by mean WT1-mRNA expression and frequency of WT1-mRNA overexpressing patients within respective subgroups. Regarding the entire group, PB WT1-mRNA expression was associated with prognosis, as those patients showing WT1-mRNA overexpression had higher risk for disease progression and AML transformation and accordingly shorter progression-free, leukemia-free and overall survival in univariate analysis. In multivariate analysis, prognostic impact of PB WT1-mRNA expression status was independent of IPSS-R and enabled more precise prediction of PFS, but not OS, within IPSS-R very low/low and intermediate risk groups. Overall, measuring PB WT1-mRNA appears valuable to support diagnostics and refine prognostication provided by the IPSS-R.

Secretome analysis of human bone marrow derived mesenchymal stromal cells

As an essential cellular component of the bone marrow (BM) microenvironment mesenchymal stromal cells (MSC) play a pivotal role for the physiological regulation of hematopoiesis, in particular through the secretion of cytokines and chemokines. Mass spectrometry (MS) facilitates the identification and quantification of a large amount of secreted proteins (secretome), but can be hampered by the false-positive identification of contaminating proteins released from dead cells or derived from cell medium. To reduce the likelihood of contaminations we applied an approach combining secretome and proteome analysis to characterize the physiological secretome of BM derived human MSC. Our analysis revealed a secretome consisting of 315 proteins. Pathway analyses of these proteins revealed a high abundance of proteins related to cell growth and/or maintenance, signal transduction and cell communication thereby representing key biological functions of BM derived MSC on protein level. Within the MSC secretome we identified several cytokines and growth factors such as VEGFC, TGF-β1, TGF-β2 and GDF6 which are known to be involved in the physiological regulation of hematopoiesis. By comparing the peptide patterns of secretomes and cell lysates 17 proteins were identified as candidates for proteolytic processing. Taken together, our combined MS work-flow reduced the likelihood of contaminations and enabled us to carve out a specific overview about the composition of the secretome from human BM derived MSC. This methodological approach and the specific secretome signature of BM derived MSC may serve as basis for future comparative analyses of the interplay of MSC and HSPC in patients with hematological malignancies.

Transforming growth factor β1-mediated functional inhibition of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia

Mesenchymal stromal cells are involved in the pathogenesis of myelodysplastic syndromes and acute myeloid leukemia, but the underlying mechanisms are incompletely understood. To further characterize the pathological phenotype we performed RNA sequencing of mesenchymal stromal cells from patients with myelodysplastic syndromes and acute myeloid leukemia and found a specific molecular signature of genes commonly deregulated in these disorders. Pathway analysis showed a strong enrichment of genes related to osteogenesis, senescence, inflammation and inhibitory cytokines, thereby reflecting the structural and functional deficits of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia on a molecular level. Further analysis identified transforming growth factor β1 as the most probable extrinsic trigger factor for this altered gene expression. Following exposure to transforming growth factor β1, healthy mesenchymal stromal cells developed functional deficits and adopted a phenotype reminiscent of that observed in patient-derived stromal cells. These suppressive effects of transforming growth factor β1 on stromal cell functionality were abrogated by SD-208, an established inhibitor of transforming growth factor β receptor signaling. Blockade of transforming growth factor β signaling by SD-208 also restored the osteogenic differentiation capacity of patient-derived stromal cells, thus confirming the role of transforming growth factor β1 in the bone marrow microenvironment of patients with myelodysplastic syndromes and acute myeloid leukemia. Our findings establish transforming growth factor β1 as a relevant trigger causing functional inhibition of mesenchymal stromal cells in myelodysplastic syndromes and acute myeloid leukemia and identify SD-208 as a candidate to revert these effects.

Abstract 2408: Epigenomic characterization of MSC from myeloid malignancies

Ineffective hematopoiesis is a hallmark of myeloid malignancies such as Myelodysplastic Syndromes (MDS) or Acute Myeloid Leukemia (AML). Our previous research has shown that mesenchymal stromal cells (MSC), one of the main cellular regulatory components of the bone marrow niche and essential for the differentiation of new blood cells from Hematopoietic Stem Cells (HSC), are molecularly and functionally impaired in MDS and AML patients. More specifically, these cells display reduced proliferative and differentiation capacities, an increased cellular senescence, or the altered expression of key hematopoietic factors, defects that can provide an explanation for the cytopenia associated with these diseases. But most interestingly, we have also discovered that MDS- and AML-derived MSC present aberrant methylomes. Our data, based on 450k DNA methylation microarrays, show that these abnormalities are shared by the MSC from both malignancies and affect key transcription factors like TBX15, PITX2 or HOXB6, formerly linked to differentiation and development. This results can account for some of the defects observed in the disease-related MSC and represent an important paradigm for cancer-induced epigenetic changes in normal cells. Aiming to further explore the importance of this epigenetic deregulation, we performed RNAseq experiments using MSC from healthy donors as well as from MDS and AML patients. This approach not only suggests a profound impact of the epigenetic aberrancies on gene expression, but also allowed us to identify TGFβ as the soluble factor that, released by the malignant cells in the bone marrow, appears to trigger the above-mentioned defects in the MDS- and AML-derived MSC. Indeed, our results show that, when treated with TGFβ, healthy MSC undergo the deregulation of TBX15, PITX2 or HOXB6 and develop some of the observed aberrant phenotypes. Conversely, the treatment of MDS- and AML-derived MSC with a TGFβ antagonist like SD208 can abrogate these effects. Finally, our preliminary DNA methylation data reveal a very similar deregulation in the methylome of MSC from Multiple Myeloma (MM) patients, strongly suggesting that the same scenario could also be common to other hematological malignancies from the lymphoid branch.

Citation Format: Manuel Rodríguez-Paredes, Stefanie Geyh, Mahshid Gazorpak, Julian Gutekunst, Felix Bormann, Rainer Haas, Thomas Schröder, Frank Lyko. Epigenomic characterization of MSC from myeloid malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2408. doi:10.1158/1538-7445.AM2017-2408

Axl blockade in vitro and in patients with high-risk MDS by the small molecule inhibitor BGB324

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Background: The interplay with bone marrow stroma plays an important role in the pathobiology of MDS. Gas6 is secreted by mesenchymal bone marrow stroma cells and promotes survival and therapy resistance of AML cells expressing the Axl receptor. We hypothesized that inhibiting Axl by the small molecule inhibitor BGB324 might hold therapeutic potential in MDS. Methods: We investigated the inhibitory effect of BGB324 on primary bone marrow mononucleated cells (BMMNC) and mesenchymal stroma cells (MSC) from MDS patients in comparison to healthy donors. In the ongoing first-in-patient Phase 1a/b trial BGBC003 A standard 3 + 3 dose escalation study was performed to identify the maximum tolerated dose of BGB324 in patients with previously treated high risk MDS or AML. BGB324 was administered as an oral loading dose on days one and two followed by a reduced daily maintenance. Three dose levels were explored 400/100mg, 600/200mg and 900/300mg. Results: We found that BGB324 inhibited BMMNC from low- and high-risk MDS patients with an IC50 of 2.1 µM and 3.8 µM, respectively (n = 5). In comparison, BMNNC from healthy donors were resistant to BGB324 (IC50 9.4 µM, p < 0.05, n = 10). Axl expression was present in MSC isolated from the BM of MDS patients and BGB324 inhibited the proliferation of MSC from low- and high-risk MDS patients (IC50 2.5 µM and 2.7 µM, respectively; n = 7/5).To date, 3 patients with MDS were treated with 400 mg loading dose and 100 mg maintenance dose of BGB324. Therapy has been well-tolerated and the MTD has not yet been reached. The majority of adverse events reported have been Grade 1 and 2. The most common related adverse events are diarrhea and fatigue. One patient with MDS was treated for 80 weeks and experienced a PR. Evidence of target inhibition was demonstrated by almost complete inhibition of Axl phosphorylation accompanied by reduction in phosphoErk and phosphoAkt signalling at day 21 of treatment. Conclusions: BGB324 is well-tolerated and might represent a promising novel treatment approach in MDS. Safety and efficacy of BGB324 will be explored further in clinical trials. Clinical trial information: NCT02488408.

Mesenchymal stromal cells in myeloid malignancies

Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) are clonal myeloid disorders characterized by hematopoietic insufficiency. As MDS and AML are considered to originate from genetic and molecular defects of hematopoietic stem and progenitor cells (HSPC), the main focus of research in this field has focused on the characterization of these cells. Recently, the contribution of BM microenvironment to the pathogenesis of myeloid malignancies, in particular MDS and AML has gained more interest. This is based on a better understanding of its physiological role in the regulation of hematopoiesis. Additionally, it was demonstrated as a ‘proof of principle’ that genetic disruption of cells of the mesenchymal or osteoblastic lineage can induce MDS, MPS or AML in mice. In this review, we summarize the current knowledge about the contribution of the BM microenvironment, in particular mesenchymal stromal cells (MSC) to the pathogenesis of AML and MDS. Furthermore, potential models integrating the BM microenvironment into the pathophysiology of these myeloid disorders are discussed. Finally, strategies to therapeutically exploit this knowledge and to interfere with the crosstalk between clonal hematopoietic cells and altered stem cell niches are introduced.

Personal factors in systemic sclerosis and their coverage by patient-reported outcome measures. A multicentre European qualitative study and literature review

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease where thickening of the skin can lead to reduced body function and limitations in activities. Severe forms can also affect and seriously damage inner organs. Patient-centred rehabilitation emphasises considerations of patients' background, experience and behavior which highlights the need to know if patient-reported outcome measures (PROMs) include such personal factors.

AIM

To identify and describe personal factors in the experiences of functioning and health of persons with SSc and to examine if and to what extent PROMs in SSc research cover these factors.

DESIGN

Data from a qualitative study with focus group interviews were analysed. PROMs in SSc research were identified in a literature review between 2008-2013.

SETTING

Participants were recruited from outpatient clinics at rheumatology department.

POPULATION

Sixty-three patients with SSc from four European countries participated.

METHODS

Data from interviews were analysed using a structure of personal factors developed by Geyh et al. Identified PROMs were analysed and linked to main concepts, related to the personal factors, found in the interview data.

RESULTS

Nineteen main concepts were related to the area "patterns of experience and behaviour" in the personal factor structure, 16 to "thoughts and beliefs", nine to "feelings", one to "motives" and one to "personal history and biography", respectively. Among the 35 PROMs identified, 15 did not cover any of the identified concepts. Concepts within the area "feelings" were mostly covered by the PROMs. Five of the PROMs covered "patterns of experience and behaviour", while "motives" and "personal history and biography" were not covered at all. Four of the identified PROMs covered concepts within the areas "feelings", "thoughts and beliefs" and "patterns of experience and behaviour" in the same instrument. The Illness Cognition Questionnaire and Illness Behaviour Questionnaire were such PROMs.

CONCLUSION

Patterns of experience and behaviour had the highest number of concepts related to personal factors, but few of the PROMs in SSc research covered these factors. Only a few PROMs covered several personal factors areas in the same instrument.

CLINICAL REHABILITATION IMPACT

The results would be of value when developing core sets for outcome measurements in SSc.

Insufficient stromal support in MDS results from molecular and functional deficits of mesenchymal stromal cells

Ineffective hematopoiesis is a major characteristic of myelodysplastic syndromes (MDS) causing relevant morbidity and mortality. Mesenchymal stromal cells (MSC) have been shown to physiologically support hematopoiesis, but their contribution to the pathogenesis of MDS remains elusive. We show that MSC from patients across all MDS subtypes (n=106) exhibit significantly reduced growth and proliferative capacities accompanied by premature replicative senescence. Osteogenic differentiation was significantly reduced in MDS-derived MSC, indicated by cytochemical stainings and reduced expressions of Osterix and Osteocalcin. This was associated with specific methylation patterns that clearly separated MDS-MSC from healthy controls and showed a strong enrichment for biological processes associated with cellular phenotypes and transcriptional regulation. Furthermore, in MDS-MSC, we detected altered expression of key molecules involved in the interaction with hematopoietic stem and progenitor cells (HSPC), in particular Osteopontin, Jagged1, Kit-ligand and Angiopoietin as well as several chemokines. Functionally, this translated into a significantly diminished ability of MDS-derived MSC to support CD34+ HSPC in long-term culture-initiating cell assays associated with a reduced cell cycle activity. Taken together, our comprehensive analysis shows that MSC from all MDS subtypes are structurally, epigenetically and functionally altered, which leads to impaired stromal support and seems to contribute to deficient hematopoiesis in MDS.

DLK-1 as a marker to distinguish unrestricted somatic stem cells and mesenchymal stromal cells in cord blood

In addition to hematopoietic stem cells, cord blood (CB) also contains different nonhematopoietic CD45-, CD34- adherent cell populations: cord blood mesenchymal stromal cells (CB MSC) that behave almost like MSC from bone marrow (BM MSC) and unrestricted somatic stem cells (USSC) that differentiate into cells of all 3 germ layers. Distinguishing between these populations is difficult due to overlapping features such as the immunophenotype or the osteogenic and chondrogenic differentiation pathway. Functional differences in the differentiation potential suggest different developmental stages or different cell populations. Here we demonstrate that the expression of genes and the differentiation toward the adipogenic lineage can discriminate between these 2 populations. USSC, including clonal-derived cells lacking adipogenic differentiation, strongly expressed &#x03B4;-like 1/preadipocyte factor 1 (DLK-1/PREF1) correlating with high proliferative potential, while CB MSC were characterized by a strong differentiation toward adipocytes correlating with a weak or negative DLK-1/PREF1 expression. Constitutive overexpression of DLK-1/PREF1 in CB MSC resulted in a reduced adipogenic differentiation, whereas silencing of DLK-1 in USSC resulted in adipogenic differentiation.

Validation of the Brief ICF core set for low back pain from the Norwegian perspective

AIM

The aim of this study was to identify candidate categories from the International Classification of Functioning, Disability and Health (ICF) to be included in the Brief ICF Core Set for low back pain (LBP) by examining their relation to general health and functionality.

METHODS

This was part of an international multicentre study with 118 participating Norwegian patients with LBP. The Comprehensive ICF Core Set for LBP was filled in by health professionals. The patients reported their health-related quality of life in the Medical Outcome Study Short Form 36 (SF-36) and function in the Oswestry Disability Index. Two questions regarding the patient's general health and functioning were completed by the health professionals and the patients themselves. Regression models were developed in order to identify ICF categories explaining most of the variance of the criterion measures.

RESULTS

Twelve ICF categories remained as significant explanatory factors according to the eight regression models, four of which were not included in a previously proposed Brief ICF Core Set for LBP.

CONCLUSIONS

The present study complements the development of the Brief ICF Core Set for LBP, and indicates a minimum number of categories needed to explain LBP patients' functioning and health. Further elaboration of the Brief ICF Core Set for LBP with multinational data is needed.

Does the International Classification of Functioning, Disability and Health (ICF) core set for low back pain cover the patients' problems? A cross-sectional content-validity study with a Norwegian population

AIM

The aim of this work was to evaluate the Norwegian form of the International Classification of Functioning, Disability and Health (ICF) Core Set for low back pain patients and investigate the feasibility of the Core Set in clinical practice.

METHODS

This was part of an international multicenter study with 118 participating Norwegian patients referred to Departments of Physical Medicine and rehabilitation with low back pain (LBP). The ICF Core Set for LBP was filled in by the health professionals. The patients reported their problems using the Medical Outcome Study Short Form 36 (SF-36) and the Oswestry Low Back Pain Disability Questionnaire (ODI).

RESULTS

The ICF Core Set categories capture the problems of the LBP patients, and few categories were reported to be missing. Many problems were reported within body function, and problems within work and employment were captured by the activity and participation component. The environmental factors in ICF were most frequently scored as facilitators, but the same factor could also represent a barrier in other individuals. Health professionals, family and friends were important factors within this domain. Few problems were scored as severe or complete indicating the need of collapsing the qualifier levels. Scoring of the ICF Core Set was feasibly, but rather time-consuming.

CONCLUSION

The ICF Core Set for LBP captures the problems of LBP, and adds important aspects to clinical practice in the field of LBP. However, the ICF Core Set for LBP needs further elaboration in order to improve the clinical feasibility.

Content comparison of health-related quality of life measures used in stroke based on the international classification of functioning, disability and health (ICF): a systematic review

OBJECTIVE

To examine and compare the contents of health-related quality of life (HRQoL) measures used in stroke, based on the ICF as the frame of reference.

DESIGN

We conducted a systematic literature review to select current generic and condition-specific HRQoL measures applied in stroke. We examined the contents of the selected measures by linking the concepts within the instruments' items to the ICF.

RESULTS

The systematic literature review resulted in the selection of six generic and seven stroke-specific HRQoL measures. Within the selected instruments we identified 979 concepts. To map these concepts, we used 200 different ICF categories. None of the ICF categories is contained in all of the instruments. The most frequently used category is 'b152 Emotional functions' contained in 53 items from 10 instruments. Stroke-specific measures more often address 'Mental functions', while the selected generic instruments more often include Environmental Factors.

DISCUSSION

The present study provides an overview on current HRQoL measures in stroke with respect to their covered contents and provides valuable information to facilitate the selection of appropriate instruments for specific purposes in clinical as well as research settings.

Linking osteoarthritis-specific health-status measures to the International Classification of Functioning, Disability, and Health (ICF)

OBJECTIVES

The objective of this study was to link the Western Ontario and McMaster Universities (WOMAC) and Lequesne-Algofunctional indices to the ICF on the basis of linking rules developed specifically to accomplish this aim. The linking process enables the understanding of the relationship between health-status measures and the ICF.

METHODS

Since the fifth World Health Organisation/International Liege Against Rheumatism (WHO/ILAR) Task Force and the Outcome Measures in Rheumatology Clinical Trials (OMERACT) group recommend the use of WOMAC and the Lequesne-Algofunctional indices in patients with osteoarthritis of the hip and knee in clinical trials, these two health-status measures have been used in this study. Both health-status measures were linked to the ICF separately by two trained health professionals. Consensus between health professionals was used to decide which ICF category should be linked to each item/concept of the two questionnaires. To resolve disagreements between the two health professionals, a third person trained in the linking rules was consulted.

RESULTS

Except for the concept of 'morning stiffness', both health professionals agreed on the ICF category chosen to link all the items/concepts of both questionnaires. Altogether, 29 different ICF categories have been linked. Five ICF categories belong to the ICF component 'body functions', 23 categories to the component 'activities and participation', and one category to 'environmental factors'. Both questionnaires have 10 ICF categories in common.

CONCLUSIONS

The results of the linking process reflect both the structure of the two questionnaires studied and the relationship between them, showing that the ICF classification can become the cardinal reference for existing health-status measures.