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Mit S-303 pathogenreduzierten Erythrozytenkonzentraten können sowohl infektiöse also auch nicht-infektiöse Risiken einer Transfusionen möglicherweise weiter reduziert werden. Frühere Studien mussten abgebrochen werden, da Antikörper gegen S-303-behandelte Erythrozyten festgestellt wurden. S-303 reagiert als unerwünschten Nebeneffekt auch mit Oberflächenmolekülen der roten Blutkörperchen. Dabei wird die Acridin-Komponente von S-303 auf der Oberfläche der roten Blutkörperchen gebunden. Gegen diese Acridin-Komponente können nach Transfusion von pathogenreduzierten EK immuninduzierte AK gebildet werden. Es existieren aber auch natürlich präformierte AK gegen S-303-behandelte Erythrozytenkonzentrate. Das Verfahren wurde modifiziert, indem der Anteil von GSH erhöht wurde. Dadurch wird vermehrt S-303 im Extrazellulärraum abgefangen und weniger Acridin auf der Oberfläche der Erythrozyten gebunden.
In dieser Studie wurden 9671 potentiell transfusionsbedürftigen Patienten auf einen natürlich präformierten Antikörper gegen S-303-behandelte Erythrozytenkonzentrate untersucht. Diese Patienten hatten zuvor noch keine S-303-behandelten Erythrozytenkonzentrate erhalten. Es wurden Testzellen von Blutspendern der Blutgruppe 0 hergestellt. Aus jedem EK wurden drei unterschiedliche Testzellen hergestellt (Erstgenerationszellen, Zweitgenerationszellen, Kontrollzellen). Das Screening erfolgte mittels IAT in Gelkartentechnik mit einer Testzelle der ersten und zweiten Generation. Die Antikörper wurden weiter charakterisiert bezüglich Spezifität, Titer, Antikörperklasse und –subklasse, Affinität und Temperaturreaktivität.
Bei zwölf Patienten konnte ein AK gegen S-303 pathogenreduzierte Erythrozy-tenkonzentrate nachgewiesen werden und somit konnte gezeigt werden, dass die Prävalenz eines solchen Antikörpers gering ist. Bei elf Patienten handelt es sich um einen Anti-Acridin-AK. Alle elf Patienten hatten immer einen positiven AKS mit der Erstgenerationszelle, jedoch nicht mit der Zweitgenerationszelle. Die Sensitivität, einen AK gegen Acridin mit der Erstgenerationszelle zu finden, ist höher als mit der Zweitgenerationszelle. Die Erstgenerationszelle hat auf ihrer Oberfläche mehr Acridin gebunden als die Zweitgenerationszelle. Bei einem Patienten konnte ein AK unbekannter Spezifität nachgewiesen werden, welcher jedoch ausschließlich mit der Zweitgenerationszelle reagierte. Vor einer möglichen Transfusion von S-303 pathogenreduzierten Erythrozytenkonzentraten wird empfohlen immer eine Testung auf Antikörper gegen Testzellen der ersten und der zweiten Generation durchzuführen. Eine Transfusion sollte grundsätzlich nur erfolgen, wenn weder ein AK gegen die Erstgenerationszelle noch gegen die Zweitgenerationszelle nachgewiesen wurde. Insgesamt handelt es sich überwiegend um niedrigtitrige IgG-AK der Subklasse 2 oder 4. Es lässt sich daher vermuten, dass natürlich präformierten AK gegen S-303-behandelte Erythrozytenkonzentrate nur eine geringe klinische Relevanz haben.
Eine klinischen Studie mit 51 kardiochirurgischen Patienten zeigte, dass nach Transfusion von pathogenreduzierten Erythrozytenkonzentraten der zweiten Generation keine immuninduzierten Antikörper gebildet wurden. Somit ist davon auszugehen, dass die Zweitgenerationszelle wegen der geringen Expression von Acridin auf der Zelloberfläche weniger immunogen ist als die Erstgenerationszelle. Klinische Studien mit einer größeren Anzahl an Patienten können nun grundsätzlich geplant werden.
Generell sollten Patienten mit natürlich präformierten Antikörpern gegen S-303-behandelte Erythrozytenkonzentrate keine pathogenreduzierten Erythrozytenkonzentrate erhalten. Patienten, welche nach Transfusion von S-303-behandelten Erythrozytenkonzentraten AK gegen die pathogenreduzierten Erythrozyten gebildet haben, sollten regelmäßig nachuntersucht werden, um eine Hämolyse frühzeitig zu entdecken.
The endosteal bone marrow niche and vascular endothelial cells provide sanctuaries to leukemic cells. In murine chronic myeloid leukemia (CML) CD44 on leukemia cells and E-selectin on bone marrow endothelium are essential mediators for the engraftment of leukemic stem cells (LSC). We hypothesized that non-adhesion of CML-initiating cells to E-selectin on the bone marrow endothelium may lead to superior eradication of LSC in CML after treatment with imatinib than imatinib alone. Indeed, here we show that treatment with the E-selectin inhibitor GMI-1271 in combination with imatinib prolongs survival of mice with CML via decreased contact time of leukemia cells with bone marrow endothelium. Non-adhesion of BCR-ABL1+ cells leads to an increase of cell cycle progression and an increase of expression of the hematopoietic transcription factor and protooncogene Scl/Tal1 in leukemia-initiating cells (LIC). We implicate SCL/TAL1 as indirect phosphorylation target of BCR-ABL1 and as a negative transcriptional regulator of CD44 expression. We show that increased SCL/TAL1 expression is associated with improved outcome in human CML. These data demonstrate the BCR-ABL1-specific, cell-intrinsic pathways leading to altered interactions with the vascular niche via the modulation of adhesion molecules - a strategy therapeutically exploitable in future.
BH3 mimetics are novel anticancer therapeutics that induce apoptosis by targeting anti‐apoptotic BCL‐2 proteins. Highly specific inhibitors of the main anti-apoptotic proteins BCL-2, BCL‐XL and MCL‐1 promise new opportunities for the treatment of AML. However, it is currently unclear which of these anti-apoptotic BCL-2 proteins represents the most promising target in AML. Therefore, we investigated the effect of BH3 mimetics targeting either BCL-2 (ABT-199, S55746), BCL-XL (A-1331852) or MCL-1 (S63845) on eleven AML cell lines. Drug sensitivity screening revealed heterogeneous sensitivity towards the different BH3 mimetics, with the best responses observed upon targeting of MCL-1. Selected cell lines that displayed sensitivity towards the specific BH3 mimetics underwent intrinsic apoptosis, which was characterized by loss of mitochondrial membrane potential, exposure of phosphatidylserine and activation of caspases. Furthermore, S63845 turned out to displace BIMS and NOXA from MCL-1 to induce apoptotic cell death. Importantly, the translational relevance of this study was demonstrated by experiments in primary AML blasts, which displayed similar sensitivity towards BH3 mimetics as the cell lines did. Additionally, experiments with nonmalignant cells could confirm the clinical relevance of the MCL-1 inhibitor. There we could show, that S63845 does not cause cytotoxicity on HPCs at efficacious doses.
In conclusion, our findings reveal that the inhibition of BCL-2 proteins, especially MCL-1, by BH3 mimetics can be a promising strategy in AML treatment.
B-cell acute lymphoblastic leukaemia (B-ALL) is characterized by the overproduction of lymphoblasts in the bone marrow (BM), and it is the most common cancer in children while being comparatively uncommon in adults. On the other hand, in chronic myeloid leukaemia (CML), 70% of cases are found in patients older than 50 years, making it uncommon in children. All CML cases and up to 3% of paediatric B- ALL (and 25% of adult B-ALL) cases are due to fusion gene BCR-ABL1, which gives rise to the cytoplasmatic, constitutively active oncoprotein, tyrosine kinase BCR-ABL1 through a reciprocal translocation between chromosomes 9 and 22. The constitutively active BCR-ABL tyrosine kinase leads to deregulation of different signal transduction pathways such as cell growth, proliferation and cell survival. The role of the bone marrow microenvironment (BMM) can mediate disease initiation (only in mice), progression, therapy resistance, and relapse, as has been increasingly recognized over the last two decades. In general, the BMM is a very complex arrangement of various cell types such as osteoblasts, osteoclasts, endothelial cells, adipocytes, mesenchymal stromal cells, macrophages and several others. In addition, the BMM is composed of multiple chemical and mechanical factors and extra cellular matrix (ECM) proteins which contribute to the BMM’s features influencing leukaemia behaviour. Considering the incidence of B-ALL and CML in children and in adults respectively, we hypothesized that the young and/or an aged BMM might also play a previously unrecognized role in the aggressiveness of B-ALL and CML. We proposed that BM, transduced with BCR-ABL1-expressing retrovirus in the murine transduction/transplantation model of B-ALL, transplanted into young versus old recipient mice would lead to a more aggressive disease in young mice, and similarly CML would be more aggressive in old recipient mice. In close recapitulation with the human incidence, induction of CML led to a significantly shorted survival in old recipient mice. On the other hand, induction of B-ALL showed a shortened survival in young compared to old syngeneic mice, as well as in a xenotransplantation model. Among the highly heterogenous composition of the BMM, we implicate young BM macrophages as a supportive niche for B-ALL cells. The results were found to be mostly due to potential soluble factors differentially secreted from young and old macrophages. Therefore, we hypothesized that the chemokine CXCL13, which has been demonstrated to play a role in B cell migration and act as a diagnostic marker in the cerebrospinal fluid of patients with neuroborreliosis, might be responsible for the observed phenotype. CXCL13 was found to be more highly expressed in healthy and leukaemic young mice as well as in conditioned medium of young macrophages. Using a variety of in vitro experiments, CXCL13 showed to significantly increase the proliferation and the migration of leukaemia cells when exposed to young macrophages, and the phenotype was rescued while using a CXCL13 neutralizing antibody. The CXCL13 role was also confirmed in vivo, since macrophage ablation led to a prolongation of survival in young mice and a reduction of CXCL13 levels. The use of an additional mouse model, leukaemia cells with CXCR5 deficiency, led to a significant prolongation of survival of young mice, confirming the importance of the CXCL13-CXCR5 axis in B-ALL. In line with our murine results, we found that human macrophages and CXCL13 levels were higher in pediatric B-ALL patients than in adults. Consistent with our murine data, the expression level of CXCR5 may act as a prognostic marker in B-ALL, as well as a predictive marker for central nervous system relapse in human B-ALL. The overall findings show that a young BMM, and in particular macrophages, influences B-ALL progression. We specifically identified CXCL13, secreted by young macrophages, as a promoter of proliferation of B-ALL cells, influencing survival in B-ALL via CXCR5. The CXCR5-CXCL13 axis may be relevant in human B-ALL, and higher CXCR5 expression in human B-ALL may act as a predictive marker.
Der Einfluss von Chemotherapie bei malignen pädiatrischen Erkrankungen auf kindliche Impftiter
(2021)
Hintergrund: Chemotherapie hat nicht nur einen Einfluss auf die Krebszellen, sondern auch auf das Immunsystem der Behandelten. In unserer Studie untersuchten wir den Impftiterverlust impfpräventablen Erkrankungen (Masern, Mumps, Röteln und Varizella zoster) bei Kindern und Jugendlichen, welche eine chemotherapeutische Behandlung wegen einer malignen Erkrankung erhielten.
Methoden: Eingeschlossen in die retrospektive Studie wurden Kinder, Jugendliche und junge Erwachsene im Alter bis zum 21. Lebensjahr, welche zwischen 2001 und 2010 an der Kinderklinik für Hämatologie und Onkologie der Universitätsklinik Frankfurt am Main therapiert wurden. Es erfolgte die Analyse von Antikörper-Titer für Masern, Mumps, Röteln und Varizella zoster zum Diagnosezeitpunkt und erneut bis zu 12 Monate nach Therapieende.
Ergebnis: Insgesamt konnten 195 Kinder und Jugendliche in die Studie eingeschlossen werden. 122 Probanden waren männlich, 73 weiblich. Die größte Patientengruppe war an ALL erkrankt (80 Patienten). Die übrigen Patienten verteilten sich auf 15 Patienten mit AML, 18 Patienten mit NHL, 22 Patienten mit Hodgkin Lymphom. 60 Patienten waren an soliden Tumoren erkrankt. Insgesamt haben 27%, 47%, 19% und 17% der Kinder und Jugendlichen ihren Impfschutz gegen Masern, Mumps, Röteln und Varizella zoster verloren. Hierbei zeigte sich eine Altersabhängigkeit. In der Auswertung zeigte sich bei jüngeren Kindern unter 7 Jahren häufiger ein Titerverlust als bei den älteren Kindern und Jugendlichen. Auch an ALL-erkrankte und behandelte Kinder und Jugendliche verloren häufiger ihren Impfschutz als die Patienten mit anderen untersuchten Krebserkrankungen (AML, NHL, M. Hodgkin, solide Tumore).
Fazit: Die Daten unserer retrospektiven Studie zeigen, dass eine signifikante Anzahl von Kindern und Jugendlichen durch eine chemotherapeutischen Behandlung ihre vorbestehenden Impftiter gegen impfpräventable Erkrankungen wie Masern, Mumps, Röteln und Varizella zoster verlieren. Dieser Verlust zeigt sich häufiger bei jüngeren Patienten und ALL-Patienten. Unsere Daten unterstreichen daher, wie wichtig es ist, Kinder und Jugendliche nach Beendigung der Chemotherapie erneut zu impfen, um einen neuen ausreichenden Impfschutz gegen Masern, Mumps, Röteln und Varizella zoster zu erhalten.
Leukemia is a cancer of the blood and bone marrow characterized by an uncontrolled proliferation and accumulation of abnormal white blood cells. Leukemia can be classified based on the course of the disease (acute or chronic) and the blood cell type involved (myeloid or lymphocytic), leading to four main subtypes: acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML). Leukemia represents 2.5% of all new cancer cases per year, and survival rates in some leukemias remain low at 40%.
The bone marrow microenvironment (BMM) is a system within the bone marrow comprising cellular and acellular components, all of which play a major role in hematopoiesis, providing the physical space where hematopoietic stem cells (HSCs) reside. The BMM interacts with HSCs, offering a “niche” for those cells and in case of leukemia, the BMM has a supportive role in disease maintenance and progression by supporting Leukemia stem cells (LSCs). One of the components of the BMM are calcium ions. Calcium is the most abundant mineral in the body, a key component of bones and is released by parathyroid hormone (PTH) induced bone remodeling. Calcium ions play a role in the localization, engraftment and adhesion of normal HSC to extracellular matrix (ECM) proteins in the BMM via the calcium sensing receptor (CaSR), thereby maintaining normal hematopoiesis. In addition of a major regulator of calcium homeostasis, CaSR contribute to the development of different cancers, functioning as either tumor suppressor or oncogene, depending on the involved tissue. However, the role of CaSR and its associated pathways in the local BMM for the development of leukemia is poorly understood. We hypothesized that calcium ions released from bone, subject to a fine balance between osteoblasts and osteoclasts, and/or CaSR, contribute to development, progression and response to therapy.
We have shown that the local calcium concentration forms a gradient in the bone marrow niche and in mice with CML is similarly low as in control mice, but significantly higher in mice suffering from BCR ABL1 driven B ALL or MLL AF9 driven AML. Similarly, the calcium concentration in the human BMM was found to be higher in AML than in other leukemias. Regarding the function of calcium in leukemia cells, we found that AML and CML cells respond differently to calcium exposure, with AML cells exhibiting regulation of cellular processes such as adhesion to the ECM protein fibronectin and migration toward CXCL 12, whereas CML cells remained mostly unaltered. Using genetic deletion or overexpression of CaSR in murine models of leukemia, we observed that CaSR acts as tumor suppressor in BCR-ABL1 driven CML and B ALL and as oncogene in AML.
Focusing on AML, our data shows that deficiency of CaSR on LICs leads, on one hand to increased apoptosis, and on the other hand to reduced cell cycle, reactive oxygen species (ROS) production and DNA damage in vivo, which may explain the observed prolongation of survival of mice. Complementary, in vitro experiments demonstrated that cells overexpressing CaSR have a distinct, cancer promoting phenotype compared to wildtype cells. Overexpression of CaSR led to an increase in proliferation, cell cycle, ROS production, DNA damage and reduced apoptosis. We have identified CaSR mediated pathways in AML and shown that CaSR enhances leukemia progression by activating MAPK/ERK and Wnt β catenin signaling. In addition, the CaSR interacting protein filamin A (FLNA) was shown to contribute to aggressive disease in vitro and in vivo. Furthermore, the mechanism underlying the role of CaSR in AML pathogenesis and possible regulation of LSCs was studied. Our findings demonstrated that CaSR ablation reduces myeloid progenitor function and proved that CaSR is required for maintenance of LSC pool by regulating its frequency and function. Further supporting the role of CaSR in LSC maintenance, genes associated with AML stemness and self renewal capacity were upregulated when CaSR was overexpressed and downregulated when CaSR was depleted. Given the role of CaSR in AML, the CaSR antagonist NPS 2143 was tested in vivo. The combination treatment of NPS 2143 with the standard of care, ara C, significantly reduced the tumor burden and prolonged the survival of mice with AML in syngeneic and xenotransplantation experiments. Based on the finding that CaSR functions as a tumor suppressor in CML, treatment of mice with the CaSR agonist cinacalcet in combination with imatinib prolonged survival of mice with CML compared to treatment with the mice given vehicle.
Our results suggest that calcium ions stemming from the calcium-rich BMM via CaSR strongly and differentially influence leukemia progression. As an adjunct to existing treatment therapies, targeting of CaSR with specific pharmacologic antagonists may prolong survival of patients with AML.
While B-cell acute lymphoblastic leukaemia (B-ALL) can be described as the leukaemia of childhood, chronic myeloid leukaemia (CML) mostly develops in elderly individuals. Understanding and utilising mechanisms involved in the development and persistence of these leukaemias as possible targets for treatment strategies has received particular interest. Processes that happen in the vicinity of the cancerous cells themselves could influence cancer growth and behaviour and hence can serve as novel targets, leading to the development of two-pronged therapies that act both on leukaemic cells directly as well as their niche. The niche in the case of leukaemia is the bone marrow microenvironment (BMM) where these cells are not only generated but also instructed and protected. As the BMM is situated inside bones that undergo drastic changes and growth processes during the ageing process, the BMM itself is also being altered throughout life. These alterations and the very process of expansion itself may therefore also provide distinct regulatory influences on the cells (healthy or malignant) that are generated inside this niche, leading to the question: Does the age of the bone marrow microenvironment differentially influence the development of (“childhood”) B-ALL versus (“adult”) CML by the release of cytokines?
In previous studies by the host-laboratory the age distribution of B-ALL versus CML in a murine transduction/ transplantation model could be recapitulated; young mice which received the same number of leukaemia-initiating cells as their old counterparts died significantly earlier of B-ALL while showing a significantly delayed clinical course, when they were suffering from CML. The tumour load and other leukaemia-associated parameters also showed a clear disposition towards preferential induction of CML in elderly and B-ALL in younger mice.
In this project we could support the hypothesis that the age of the BMM differentially influences the proliferation of leukaemic cells and thereby the development and persistence of different types of leukaemias by utilising different in vitro culture experiments. Specifically, we could show that young (compared to old) bone marrow
11 stroma cells (BMSC) support the growth of (BCR-ABL1+) B-ALL cells both in a direct, cell on cell co-culture setting, as well as in young BMSC-derived conditioned medium. This supports the hypothesis that varying factors are differentially released from a young versus an old BMM and influence the growth of the leukaemia cells. The opposite might be true for CML cells (BCR-ABL1+ 32D cells); BMSC obtained from old animals showed a tendency to support their growth more profoundly than cells acquired from young animals.
Possible proteins responsible for the distinct regulation of myeloid versus lymphatic leukaemic cells by young versus old BMM have also been studied. We investigated C-X-C motif chemokine 13 (CXCL13) and growth differentiation factor 11 (GDF11) in their effect on leukaemia cells, as both proteins having previously been described to have tumour-modelling properties and age-dependent levels (see below).
We identified an increased secretion of CXCL13, a B-cell chemotactic factor, into conditioned medium from young versus old BMSC. In accordance with this we found migration of B-ALL cells towards BMSC from young compared to old mice to be improved, while adhesion of both B-ALL and CML cells to young versus old BMSC did not show any differences. By blocking CXCL13 the proliferation-supporting effect of young BMSC on B-ALL cells could be diminished. Similar effects could be demonstrated by blocking GDF11.
In the case of CML cells we could observe the opposite effect; blocking CXCL13 and GDF11 increased their proliferation in a co-culture with BMSC. This supported our hypothesis that both cytokines differentially regulate B-ALL and CML behaviour. After the completion of this thesis, another member of the host-laboratory convincingly demonstrated the role of BMM age in the regulation of B-ALL via CXCL13 signalling (see discussion).
The Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) as well as the T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) are rare types of malignant lymphomas. Both NLPHL and THRLBCL are frequently observed in middle-aged men with THRLBCL presenting frequently with an advanced Ann-Arbor stage with B-symptoms and associated with more aggressive courses.3 However, due to the limited number of tumor cells in the tissue of both NLPHL and THRLBCL, limited numbers of studies have been conducted on these lymphomas and current results are mainly based on general molecular genetic studies.
In order to obtain a better understanding for these disease forms as well as possible changes in their nuclear and cytoplasmatic sizes, the following study relied on the comparison of the different NLPHL forms and THRLBCL in terms of nuclear size and nuclear volume. This was carried out using both 2D and 3D analysis. During the 2D analysis of nuclear size and nuclear volume no significant differences could be presented between those groups. However, the 3D analysis of NLPHL and THRLBCL pointed out a slightly enlarged nuclear volume in THRLBCL. Furthermore, the analysis indicated a significantly increased cytoplasmatic size of THRLBCL compared to NLPHL forms. Nevertheless, differences occurred not only between the tumor cells of both disease forms, but also the T cells presented a larger nuclear volume in THRLBCL. B cells, which were considered as the control group, did not demonstrate any significant differences between the different groups. The presented results suggest an increased activity of T cells in THRLBCL, which is most likely to be interpreted as a response against the surrounding tumor cells and probably limits the proliferation of the tumor cells. Based on these results, the importance of 3D analysis is also evident due to the fact that it is clearly superior to 2D analysis. For a better understanding of both disease forms, it is therefore recommended to use the 3D technique in combination with molecular genetic analysis in future research.