Acute myeloid leukaemia (AML) is a complex haematological malignancy characterised by diverse genetic alterations leading to abnormal proliferation of myeloid precursor cells. One of the most significant genetic alterations in AML involves mutations in the FLT3 gene, which plays a critical role in haematopoiesis and haematopoietic homeostasis. This review explores the current understanding of FLT3 gene mutations and isoforms and the importance of the FLT3 protein in AML. FLT3 mutations, including internal tandem duplications (FLT3-ITD) and point mutations in the tyrosine kinase domain (FLT3-TKD), occur in 25-30% in AML and are associated with poor prognosis. FLT3-ITD mutations lead to constitutive activation of the FLT3 signalling pathway, promoting cell survival and proliferation. FLT3-TKD mutations affect the tyrosine kinase domain and affect AML prognosis in various ways. Furthermore, FLT3 isoforms, including shorter variants, contribute to the complexity of FLT3 biology. Additionally, nonpathological polymorphisms in FLT3 are being explored for their potential impact on AML prognosis and treatment response. This review also discusses the development of molecular treatments targeting FLT3, including first-generation and next-generation tyrosine kinase inhibitors, highlighting the challenges of resistance that often arise during therapy. The final chapter describes FLT3 protein domain rearrangements and their relevance to AML pathogenesis.
- MeSH
- akutní myeloidní leukemie * genetika MeSH
- lidé MeSH
- mutace genetika MeSH
- protein - isoformy genetika MeSH
- tyrosinkinasa 3 podobná fms genetika MeSH
- tyrosinkinasy MeSH
- viabilita buněk MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
While type I interferon (IFN) is best known for its key role against viral infection, accumulating preclinical and clinical data indicate that robust type I IFN production in the tumor microenvironment promotes cancer immunosurveillance and contributes to the efficacy of various antineoplastic agents, notably immunogenic cell death inducers. Here, we report that malignant blasts from patients with acute myeloid leukemia (AML) release type I IFN via a Toll-like receptor 3 (TLR3)-dependent mechanism that is not driven by treatment. While in these patients the ability of type I IFN to stimulate anticancer immune responses was abolished by immunosuppressive mechanisms elicited by malignant blasts, type I IFN turned out to exert direct cytostatic, cytotoxic and chemosensitizing activity in primary AML blasts, leukemic stem cells from AML patients and AML xenograft models. Finally, a genetic signature of type I IFN signaling was found to have independent prognostic value on relapse-free survival and overall survival in a cohort of 132 AML patients. These findings delineate a clinically relevant, therapeutically actionable and prognostically informative mechanism through which type I IFN mediates beneficial effects in patients with AML.
- MeSH
- akutní myeloidní leukemie * patologie MeSH
- interferon typ I * MeSH
- lidé MeSH
- nádorové mikroprostředí MeSH
- protinádorové látky * terapeutické užití MeSH
- signální transdukce MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
NK buňky hrají u alogenní transplantace kostní dřeně významnou roli, nejen při eradikaci zbývajících nádorových buněk, ale ovlivňují i rozvoj reakce štěpu proti hostiteli. Je tedy třeba porozumět jejich regulaci a tomu, jakým způsobem může reakce imunitního systému pacienta NK buňky dárce ovlivňovat. Inhibice a aktivace NK buněk je řízena celou řadou receptorů, které reagují na široké spektrum ligandů. Ať už inhibičních, které signalizují NK buňkám, že je cílová buňka v pořádku nebo aktivačních, které vyjadřují nějaké poškození cílové buňky. Mezi nejprozkoumanější receptory patří KIR a dále NKG2D se svými ligandy MICA a MICB. Přehledu jejich role v transplantaci kostní dřeně se věnuje tato práce.
NK cells play an important role in allogeneic stem cell transplantation; not only as effector cells in the eradication of remaining cancer cells but also as potential inducers of graft versus host disease. Hence, it is important to understand their regulation and how the patient’s immune system affects donor NK cells. NK cell inhibition or activation is directed by many receptors which interact with a broad spectrum of ligands. Inhibition ligands signal that the target cell is healthy, and activating ligands reflect that the cell is damaged. The most investigated receptors are KIR together with the NKG2D receptor with its ligands MICA and MICB. This work describes their role in stem cell transplantation.
- MeSH
- akutní myeloidní leukemie * imunologie terapie MeSH
- haplotypy genetika MeSH
- HLA antigeny MeSH
- homologní transplantace MeSH
- lektinové receptory NK-buněk - podrodina K analýza genetika MeSH
- lidé MeSH
- ligandy MeSH
- polymorfismus genetický MeSH
- receptory buněk NK * imunologie klasifikace MeSH
- receptory KIR analýza genetika MeSH
- transplantace kostní dřeně MeSH
- transplantační imunologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Reakce štěpu proti hostiteli (graft versus host disease – GvHD) patří mezi nejzávažnější komplikace alogenní transplantace hematopoetických kmenových buněk. Přestože se díky optimalizaci transplantačních postupů mortalita v důsledku GvHD neustále snižuje, nadále existuje početná skupina pacientů, u kterých se rozvine život ohrožující forma GvHD, případně kterým GvHD zásadně snižuje kvalitu života po transplantaci. Jedním z inovativních přístupů, které by mohly zlepšit prognózu pacientů, je adoptivní podání některých buněčných populací, které mají imunomodulační potenciál. Na našem pracovišti jsme v rámci klinické studie podávali léčivé přípravky z mezenchymálních kmenových buněk (MSC) v léčbě steroidně-refrakterní GvHD (SR-GvHD). Nyní ověřujeme možnost využití invariantních NKT lymfocytů (iNKT) v této indikaci. Tyto iNKT lymfocyty jsou schopné tlumit patologické imunitní reakce a rozvoj příznaků GvHD a současně podporovat protinádorovou imunitu – tzv. reakci štěpu proti leukemii (graft versus leukemia – GvL). V rámci preklinického testování jsme porovnali několik šarží kultivovaných a expandovaných iNKT a MSC od různých dárců z hlediska jejich imunofenotypu a imunomodulačního potenciálu. Průtokovou cytometrií jsme kvantifikovali expresi aktivačního znaku CD25 na nespecificky stimulovaných mononukleárních buňkách po kokultivaci s MSC nebo s iNKT. Studie prokázala, že je možné připravit čistou populaci iNKT buněk s dostatečnou imunomodulační kapacitou srovnatelnou s MSC. Zdá, že iNKT buňky představují slibnou léčebnou strategii v rámci terapie potransplantačních komplikací, nicméně vzhledem k výrazné heterogenitě jejich subpopulací bude nutné provést hlubší stanovení funkce iNKT a optimalizovat protokol pro jejich přípravu.
Graft versus host disease (GvHD) is one of the most serious complications of allogeneic hematopoietic stem cell transplantation. Although GvHD mortality is steadily declining due to the optimalization of transplant procedures, there remains a large group of patients who develop life-threatening forms of GvHD, or whose quality of life after transplantation is reduced due to GvHD. The adoptive administration of immunomodulatory cell populations is an innovative approach that could improve the prognosis of these patients. We had previously used mesenchymal stem cells (MSC) in steroid-refractory GvHD (SR-GvHD) in a clinical trial and we are currently verifying the possibility of using invariant NKT lymphocytes (iNKT) in SR-GvHD treatment. iNKT are a cell population that is able to suppress pathological immune responses and the development of GvHD symptoms. At the same time, iNKT are able to promote anti-tumour immunity – the graft versus leukaemia effect (GvL). In a preclinical study, we compared several batches of cultured and expanded iNKT and MSCs from different donors in terms of their immunophenotype and immunomodulatory potential. We quantified the expression of the activation marker CD25 on non-specifically stimulated mononuclear cells after co-cultivation with MSC or iNKT. The study showed that it is possible to prepare a pure population of iNKT with sufficient immunomodulatory capacity comparable to MSCs. While iNKT cells appear to be a promising treatment strategy for post-transplant complications, the significant heterogeneity of their subpopulations will require a deeper assessment of iNKT function and optimisation of their production protocols.
- Publikační typ
- abstrakt z konference MeSH
- Publikační typ
- abstrakt z konference MeSH
- Publikační typ
- abstrakt z konference MeSH
- Publikační typ
- abstrakt z konference MeSH
NKG2D and its ligands, MICA and MICB, are known as the key regulators of NK cells. NK cells are the first reconstituted cells after the allogeneic hematopoietic stem cell transplantation (HSCT); therefore, it is crucial to understand their role in HSCT outcome. In the presented study, we investigated the single amino acid changes across the exons 2-4 of MICA and MICB genes, and point mutations within the NKG2D gene, which defines the type of NKG2D haploblock (HNK/LNK) in the donors (n = 124), as well as in patients with acute myeloid leukemia (n = 78). In our cohort, we found that graft from a donor with at least one MICA allele containing glycine at position 14 (MICA-14Gly) is significantly associated with deterioration of a patient's overall survival (OS) (p < 0.05). We also observed a negative effect of MICB-58 (Lys → Glu) polymorphism on relapse-free survival (RFS), although it was not statistically significant in multivariate analysis (p = 0.069). To our knowledge, this is the first work describing the role of MICA-14 and MICB-58 polymorphisms on HSCT outcome.
- Publikační typ
- časopisecké články MeSH
Cryopreserved haematopoietic progenitor cells are used to restore autologous haematopoiesis after high dose chemotherapy. Although the cells are routinely stored for a long period, concerns remain about the maximum storage time and the possible negative effect of storage on their potency. We evaluated the effect of cryopreservation on the quality of peripheral stem cell grafts stored for a short (3 months) and a long (10 years) period and we compared it to native products.The viability of CD34+ cells remained unaffected during storage, the apoptotic cells were represented up to 10% and did not differ between groups. The clonogenic activity measured by ATP production has decreased with the length of storage (ATP/cell 1.28 nM in native vs. 0.63 in long term stored products, P < 0.05). Only borderline changes without statistical significance were detected when examining mitochondrial and aldehyde dehydrogenase metabolic activity and intracellular pH, showing their good preservation during cell storage. Our experience demonstrates that cryostorage has no major negative effect on stem cell quality and potency, and therefore autologous stem cells can be stored safely for an extended period of at least 10 years. On the other hand, long term storage for 10 years and longer may lead to mild reduction of clonogenic capacity. When a sufficient dose of stem cells is infused, these changes will not have a clinical impact. However, in products stored beyond 10 years, especially when a low number of CD34+ cells is available, the quality of stem cell graft should be verified before infusion using the appropriate potency assays.
