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Genetic and epigenetic alterations increase the expression of FLT3 in AML. (A) cBioportal database was used to analyze mutations and copy number alterations of FLT3. Genetic alterations of FLT3 in different types of cancer showed the most mutations of FLT3 in leukemia. (B) Four databases (GSE10358, GSE14468, GSE34860 and TCGA) were utilized to examine the effect of FLT3 mutations on the expression of FLT3. (C) cBioportal result showed the expression of FLT3 was negatively correlated with FLT3 methylation in leukemia. (D) Gene Expression Omnibus dataset (GDS4306) showed that DNMT1 haploinsufficiency (haplo) increased expression of Flt3 in mouse leukemia cells. FLT3, FMS-like tyrosine kinase; AML, acute myeloid leukemia; DLBC, diffuse large B-cell; GBM, glioblastoma multiforme; ccRCC, clear cell renal cell carcinoma; UC, uterine carcinosarcoma; PCPG, pheochromocytoma and paraganglioma; ACC, adenoid cystic carcinoma; pRCC, papillary renal cell carcinoma; chRCC, chromophobe renal cell carcinoma; WT, wild-type; ITD, internal tandem duplication; TKD, tyrosine kinase domain. DNMT1, DNA methyltransferase 1; * P<0.05, ** P<0.01 and *** P<0.001; ns, not significant.
Source publication
Several studies have shown that internal tandem duplication (ITD) of FMS-like tyrosine kinase 3 (FLT3) can result in the failure of leukemia treatment and contribute to a poor prognosis. However, the role of the overexpression of FLT3 in leukemia remains to be fully elucidated. By mining public database, the present study first identified that the...
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... of FLT3 is regulated by genetic and epigenetic alterations. In order to determine the mechanism increasing the expression of FLT3 in leukemia, the present study evalu- ated genetic and epigenetic alterations of FLT3 in AML. By mining TCGA data, it was found that FLT3 was significantly mutated in AML, compared with other types of cancer, which was similar to the results obtained on the expression of FLT3. The results revealed ~28% of patients with AML had somatic mutations in FLT3 (Fig. 2A). Therefore, it was hypothesized that FLT3 mutations may increase the expression of FLT3 in AML. To confirm this, the expression of FLT3 was compared between wild-type and mutated groups in four independent databases, (GSE10358, GSE14468, GSE34860 and TCGA). It was found that ITD and TKD mutations significantly increased the expression of FLT3 (Fig. 2B). In addition, methylation data from TCGA was used to compare the association between the expression of FLT3 and methylation status. In AML, the expression of FLT3 was negatively correlated with its meth- ylation (Fig. 2C), indicating that the hypomethylation of FLT3 may be a potential mechanism resulting in the upregulation of FLT3. Of note, mining of the GEO dataset (GDS4306) revealed that the haploinsufficiency of DNMT1 significantly increased the expression of Flt3 in mouse leukemia cells (Fig. 2D), suggesting that DNMT1 modified the methylation of FLT3. Collectively, these data showed that genetic and epigenetic alterations may be potential mechanisms by which the expres- sion of FLT3 is increased in ...
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... of FLT3 is regulated by genetic and epigenetic alterations. In order to determine the mechanism increasing the expression of FLT3 in leukemia, the present study evalu- ated genetic and epigenetic alterations of FLT3 in AML. By mining TCGA data, it was found that FLT3 was significantly mutated in AML, compared with other types of cancer, which was similar to the results obtained on the expression of FLT3. The results revealed ~28% of patients with AML had somatic mutations in FLT3 (Fig. 2A). Therefore, it was hypothesized that FLT3 mutations may increase the expression of FLT3 in AML. To confirm this, the expression of FLT3 was compared between wild-type and mutated groups in four independent databases, (GSE10358, GSE14468, GSE34860 and TCGA). It was found that ITD and TKD mutations significantly increased the expression of FLT3 (Fig. 2B). In addition, methylation data from TCGA was used to compare the association between the expression of FLT3 and methylation status. In AML, the expression of FLT3 was negatively correlated with its meth- ylation (Fig. 2C), indicating that the hypomethylation of FLT3 may be a potential mechanism resulting in the upregulation of FLT3. Of note, mining of the GEO dataset (GDS4306) revealed that the haploinsufficiency of DNMT1 significantly increased the expression of Flt3 in mouse leukemia cells (Fig. 2D), suggesting that DNMT1 modified the methylation of FLT3. Collectively, these data showed that genetic and epigenetic alterations may be potential mechanisms by which the expres- sion of FLT3 is increased in ...
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... of FLT3 is regulated by genetic and epigenetic alterations. In order to determine the mechanism increasing the expression of FLT3 in leukemia, the present study evalu- ated genetic and epigenetic alterations of FLT3 in AML. By mining TCGA data, it was found that FLT3 was significantly mutated in AML, compared with other types of cancer, which was similar to the results obtained on the expression of FLT3. The results revealed ~28% of patients with AML had somatic mutations in FLT3 (Fig. 2A). Therefore, it was hypothesized that FLT3 mutations may increase the expression of FLT3 in AML. To confirm this, the expression of FLT3 was compared between wild-type and mutated groups in four independent databases, (GSE10358, GSE14468, GSE34860 and TCGA). It was found that ITD and TKD mutations significantly increased the expression of FLT3 (Fig. 2B). In addition, methylation data from TCGA was used to compare the association between the expression of FLT3 and methylation status. In AML, the expression of FLT3 was negatively correlated with its meth- ylation (Fig. 2C), indicating that the hypomethylation of FLT3 may be a potential mechanism resulting in the upregulation of FLT3. Of note, mining of the GEO dataset (GDS4306) revealed that the haploinsufficiency of DNMT1 significantly increased the expression of Flt3 in mouse leukemia cells (Fig. 2D), suggesting that DNMT1 modified the methylation of FLT3. Collectively, these data showed that genetic and epigenetic alterations may be potential mechanisms by which the expres- sion of FLT3 is increased in ...
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... of FLT3 is regulated by genetic and epigenetic alterations. In order to determine the mechanism increasing the expression of FLT3 in leukemia, the present study evalu- ated genetic and epigenetic alterations of FLT3 in AML. By mining TCGA data, it was found that FLT3 was significantly mutated in AML, compared with other types of cancer, which was similar to the results obtained on the expression of FLT3. The results revealed ~28% of patients with AML had somatic mutations in FLT3 (Fig. 2A). Therefore, it was hypothesized that FLT3 mutations may increase the expression of FLT3 in AML. To confirm this, the expression of FLT3 was compared between wild-type and mutated groups in four independent databases, (GSE10358, GSE14468, GSE34860 and TCGA). It was found that ITD and TKD mutations significantly increased the expression of FLT3 (Fig. 2B). In addition, methylation data from TCGA was used to compare the association between the expression of FLT3 and methylation status. In AML, the expression of FLT3 was negatively correlated with its meth- ylation (Fig. 2C), indicating that the hypomethylation of FLT3 may be a potential mechanism resulting in the upregulation of FLT3. Of note, mining of the GEO dataset (GDS4306) revealed that the haploinsufficiency of DNMT1 significantly increased the expression of Flt3 in mouse leukemia cells (Fig. 2D), suggesting that DNMT1 modified the methylation of FLT3. Collectively, these data showed that genetic and epigenetic alterations may be potential mechanisms by which the expres- sion of FLT3 is increased in ...
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... pathways were activated in AML by ITD mutations or the overexpression of FLT3. Several interacting proteins are also reported to interact with FLT3 to negatively or positively regulate FLT3 pathways. Spleen tyrosine kinase (SYK) and the mucin 1-C-terminal subunit (MUC1-C) oncoprotein are reported to directly bind to and activate FLT3-related pathways (50,51), whereas suppressor of cytokine signaling 2 (SOCS2) and src-like adaptor protein 2 (SLAP2) interact with FLT3 protein to inhibit its signaling (52,53). In addition, the transcription of FLT3 can be regulated in AML. Certain AML-related transcription factors, including CCAAT/enhancer binding protein α and the proto-oncogene MYB, can bind to the FLT3 promoter to activate the transcrip- tion of FLT3 (54). In the present study, another two mechanism were found to increase the expression of FLT3 in AML. ITD and TKD mutations, and the methylation of FLT3 increased its expression in AML (Fig. 2B and C). In addition, DNMT1 was identified as is a potential regulator of FLT3 (Fig. ...
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... pathways were activated in AML by ITD mutations or the overexpression of FLT3. Several interacting proteins are also reported to interact with FLT3 to negatively or positively regulate FLT3 pathways. Spleen tyrosine kinase (SYK) and the mucin 1-C-terminal subunit (MUC1-C) oncoprotein are reported to directly bind to and activate FLT3-related pathways (50,51), whereas suppressor of cytokine signaling 2 (SOCS2) and src-like adaptor protein 2 (SLAP2) interact with FLT3 protein to inhibit its signaling (52,53). In addition, the transcription of FLT3 can be regulated in AML. Certain AML-related transcription factors, including CCAAT/enhancer binding protein α and the proto-oncogene MYB, can bind to the FLT3 promoter to activate the transcrip- tion of FLT3 (54). In the present study, another two mechanism were found to increase the expression of FLT3 in AML. ITD and TKD mutations, and the methylation of FLT3 increased its expression in AML (Fig. 2B and C). In addition, DNMT1 was identified as is a potential regulator of FLT3 (Fig. ...
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Acute myeloid leukemia (AML) is a very heterogeneous and highly malignant blood cancer. Mutations of the DNA methyltransferase DNMT3A are among the most frequent recurrent genetic lesions in AML. The majority of DNMT3A-mutant AML patients shows fast relapse and poor survival, but also patients with long survival or long-term remission have been rep...
Citations
... FLT3-activating mutations (e.g., FLT3-ITD and TKD) have been reported in 25%-30% AML cases (Islam et al., 2023). High c-KIT and FLT3 expression were also reported in AML cases and portend a poor prognosis (Ampasavate et al., 2019;Cheng et al., 2018;Malani et al., 2020). Interleukin-3 (IL-3) and IL-6 are hematopoietic cytokines that are secreted by both hematopoietic cells and bone marrow (BM) niche cells. ...
Lymphoid-primed multipotent progenitor (LMPP)-like and granulocyte-monocyte progenitor (GMP)-like leukemia stem cells (LSCs) co-exist in the blood of most patients with acute myeloid leukemia (AML). Complete elimination of both types of LSCs is required to cure AML. Using an MLL-AF9-induced murine AML model, we studied the role of hematopoietic cytokines in the survival of LMPP- and GMP-like LSCs. We found that SCF or FLT3L promotes the survival of LMPP-like LSCs by stimulating Stat5-mediated Mcl1 expression, whereas interleukin-3 (IL-3) or IL-6 induces the survival of GMP-like LSCs by stimulating Stat3/nuclear factor κB (NF-κB)-mediated Bcl2 expression. Functional study demonstrated that, compared to AML cells cultured in IL-3 and IL-6 medium, AML cells in SCF- or Flt3L-only culture are highly clonogenic in in vitro culture and are highly leukemogenic in vivo. Our study suggests that co-inhibition of both STAT5-MCL1 and STAT3/NF-κB-BCL2 signaling might represent an improved treatment strategy against AML, specifically AML cases with a monocytic phenotype and/or FLT3 mutations.
... Patients with high FLT3 expression also have high levels of leukemic oncogenes. As a result, high FLT3 expression is a risk factor for leukaemia [40]. Cases with FLT3-ITD mutations are associated with a higher level of WBCs and high blasts percentage, with lower hemoglobin and platelets [28,41]. ...
Background
Acute myeloid leukemia (AML) is a type of blood cancer that affects the bone marrow and blood cells. AML is characterized by the rapid growth and accumulation of abnormal white blood cells, known as myeloblasts, which interfere with the production of normal blood cells.
Aims
The main aim was to determine the relationship between these genetic alterations and the clinico-haematological parameters and prognostic factors with therapy for Iraqi patients with AML.
Methods
We used Sanger Sequencing to detect the mutations in 76 AML patients. Clinical data of AML patients were retrospectively analysed to compare the prognosis of each gene mutation group.
Results
Somatic mutations were identified in 47.4% of the enrolled patients in a core set of pathogenic genes, including FLT3 (18 patients, 23.7%), DNMT3A (14, 18.4%), NPM1 (11, 14.5%) and TP53 (5, 6.8%). As multiple mutations frequently coexisted in the same patient, we classified patients into 10 further groups. Two novel mutations were detected in FLT3-ITD, with new accession numbers deposited into NCBI GenBank (OP807465 and OP807466). These two novel mutations were computationally analysed and predicted as disease-causing mutations. We found significant differences between patients with and without the detected mutations in disease progression after induction therapy (remission, failure and death; pv = < 0.001) and statistically significant differences were reported in total leukocyte count (pv = < 0.0001).
Conclusion
These genes are among the most frequently mutated genes in AML patients. Understanding the molecular and clinical significance of these mutations is important for guiding treatment decisions and predicting patient outcomes.
... FLT3 is a promising target in AML-directed immunotherapy due to its overexpression and the correlation of high expression levels with poor prognosis. 13,15,50 Normal FLT3 expression is restricted to a fraction of CD34 + HSPCs, thus limiting some potential haematological toxicities that occur with CD33-or CD123-targeted therapies. 51 Moreover, the intermittent TM application would theoretically also reduce the risk for CAR T-cell exhaustion, which has been shown to be another factor of limited activity with constructs mediating constant activation. ...
Adaptor chimeric antigen receptor (CAR) T‐cell therapy offers solutions for improved safety and antigen escape, which represent main obstacles for the clinical translation of CAR T‐cell therapy in myeloid malignancies. The adaptor CAR T‐cell platform ‘UniCAR’ is currently under early clinical investigation. Recently, the first proof of concept of a well‐tolerated, rapidly switchable, CD123‐directed UniCAR T‐cell product treating patients with acute myeloid leukaemia (AML) was reported. Relapsed and refractory AML is prone to high plasticity under therapy pressure targeting one single tumour antigen. Thus, targeting of multiple tumour antigens seems to be required to achieve durable anti‐tumour responses, underlining the need to further design alternative AML‐specific target modules (TM) for the UniCAR platform. We here present the preclinical development of a novel FMS‐like tyrosine kinase 3 (FLT3)‐directed UniCAR T‐cell therapy, which is highly effective for in vitro killing of both AML cell lines and primary AML samples. Furthermore, we show in vivo functionality in a murine xenograft model. PET analyses further demonstrate a short serum half‐life of FLT3 TMs, which will enable a rapid on/off switch of UniCAR T cells. Overall, the presented preclinical data encourage the further development and clinical translation of FLT3‐specific UniCAR T cells for the therapy of AML.
... 7 Another postulated mechanism that promotes leukemia is the increased expression of the tyrosine kinase FLT3. 8 Two of our cases were positive for KMT2A gene rearrangement. Infants with this genetic alteration, especially those younger than 6 months, have a particularly poor prognosis. ...
Infantile leukemia is a rare hematological malignancy that occurs in the first year of life. It is an aggressive disease with peculiar immunophenotypic, cytogenetic, and molecular characteristics. It can be myeloid or lymphoid in origin. More than 80% of cases involve KMT2A gene rearrangement in the lymphoblastic subset, versus 50% in the myeloid subset. In this study, we present three cases of this rare entity to add knowledge about its clinical presentation and diagnostic profiles. These cases of infantile B-lymphoblastic leukemia (B-ALL) were retrospectively reviewed at the Department of Hematology, Section Cytogenetics at Indus Hospital and Health Network. The clinical characteristics, complete diagnostic profile, immunophenotypic profile, fluorescence in situ hybridization (FISH) results, treatments, and outcomes of the patients were assessed. All three infants were girls who presented with hyperleukocytosis, and they were diagnosed by eight-color flow cytometry. FISH studies revealed KMT2A gene rearrangement in two of the three patients. Infantile B-ALL is a biologically distinct disease carrying a poor prognosis. Female preponderance, hyperleukocytosis, and hepatosplenomegaly are common findings in this subgroup. No standard protocol for this rare entity has proven ideal for managing these young infants.
... High levels of Flk2 expression have been associated with a high risk of relapse in pediatric AML patients 41 . The overexpression of Flk2 in AML blasts has been associated with a worsened prognosis 42 . Furthermore, Flk2 deficiency in mice significantly reduced multipotent, lymphoid, and myeloid progenitors, such as MPPs, CLPs, Pro-B, and B cells but not T cells 43 . ...
After transplantation, hematopoietic stem cells (HSCs) sustain blood cell regeneration throughout the patient’s life. Recent studies suggest that several types of mature blood cells provide feedback signals to regulate HSC fate. However, the potential feedback effect of hematopoietic progenitor cells has not been characterized to date. The present investigation demonstrated that multipotent progenitors (MPPs) promoted T cell production of HSCs when both cell types were cotransplanted in mice. Using genetic barcodes to track individual HSCs in mice, we found that the increased T cell production by HSCs was associated with the combined effects of altered lineage bias and clonal expansion during HSC differentiation. We showed that MPP and HSC co-transplantation promoted the multilineage differentiation of HSCs in the short term while preserving lymphoid-specialized HSC differentiation in the long term. Our findings indicate that MPPs derived from HSCs regulate the fate of HSCs after bone marrow transplantation. Genetic barcoding technology reveals how a specific group of progenitor cells regulates the fate of hematopoietic stem cells (HSCs), the precursors of blood cells, following bone marrow transplantation. HSCs are used in bone marrow transplantation to boost blood regeneration in leukemia patients. HSCs differentiate into different groups of mature blood cells, which then form a ‘feedback loop’, influencing the fate of HSCs. The first descendants of HSCs are multipotent progenitor cells (MPPs), which are frequently transplanted alongside HSCs. Exactly how MPPs influence HSC differentiation is unclear. Rong Lu at the University of Southern California, Los Angeles, USA, and co-workers used genetic barcoding technology to track individual HSCs when they were transplanted alongside MPPs into mice. One specific group of MPPs boosted long-term T-cell production from HSCs, and also regulated the fate of HSCs over time.
... Although over 80% of pediatric ALL patients including B-ALL reach long-term remission after the standard therapy, the 5-year overall survival of adult ALL patients remains about 20 to 40% [28], suggesting there are still unmet medical needs in this population. It has been reported that the leukemic blast cells in B-ALL patients highly express FLT3 [29,30]. As for the contribution of Bcl-2 in the B-ALL, it has been reported that venetoclax single agent suppressed the growth of a B-ALL cell line or B-ALL patient-derived cells [31], suggesting that Bcl-2 contributes to the cell survival of B-ALL leukemic cells. ...
Antibody drug conjugates (ADC) are one of the attractive modalities for the treatment of acute myeloid leukemia (AML). Previously, we have developed ASP1235, a novel ADC targeting Fms-like tyrosine kinase 3 (FLT3) which is widely expressed on the leukemic blasts of AML patients. In this study, we sought to evaluate the therapeutic effect of ASP1235 in combination with venetoclax plus azacitidine, a novel standard-of-care treatment for elderly AML patients, in ASP1235 poor sensitive AML cells. To identify the suitable preclinical model, we first evaluated the growth inhibitory effect of ASP1235 on several leukemia cell lines expressing FLT3 and found that THP-1 cells were partially sensitive to ASP1235 in vitro. Furthermore, ASP1235 showed marginal anti-tumor activity in a THP-1 xenograft model. Compared to the leukemic blasts in most of the relapsed or refractory (R/R) AML patients tested, THP-1 cells expressed equivalent protein levels of Bcl-2, suggesting that ASP1235 in combination with venetoclax plus azacitidine is a rational treatment in the THP-1 model. In vitro, ASP1235 showed a cytotoxic effect on THP-1 cells in combination with venetoclax, and the combination effect was greater than the additive effect. Furthermore, ASP1235 also showed a combination effect with venetoclax plus azacitidine treatment. Similarly, the combination of ASP1235, venetoclax and azacitidine showed a superior anti-tumor effect in a THP-1 xenograft model without obvious body weight loss. These findings provide supportive evidence that the triple combination of ASP1235, venetoclax and azacitidine would improve the clinical outcome of ASP1235 monotherapy and venetoclax plus azacitidine regimen in AML patients.
... Gene mutations in the FLT3 receptor experienced by individuals with AML disease account for 30% of the total cases. It is known that the overexpression of the FLT3 receptor in AML cases is the most experienced compared to other types of cancer [46,48]. There are two types of FLT3 mutations that occur in the majority of survivors, namely internal tandem duplications (ITD) and activation loop mutations. ...
... This mutation occurs most frequently (15-35% of total cases). These mutations cause changes in receptor activity and lead to activation of signaling pathways such as STAT5, MAPK/ERK, and PI3K/Akt [47,48,49]. Meanwhile, activation loop mutations occur due to point mutations in the tyrosine kinase domain (TKD). ...
... Meanwhile, activation loop mutations occur due to point mutations in the tyrosine kinase domain (TKD). The cause of most TKD mutations in FLT3 is the conversion of aspartic acid to tyrosine at codon 835 [47,48]. Thus, it can be said that the inhibition of the mutated FLT3 receptor can be used as a therapeutic treatment. ...
Acute Myeloid Leukemia (AML) is the most common leukemia caused by genetic abnormalities that affect the hematological proliferation and induce incomplete differentiation of myeloid cells in the peripheral blood and bone marrow. AML involving FLT3 gene mutation results in overexpression of FLT3 receptors. This study intended to predict the interaction between the FLT3 receptor in AML with flavonoids found in Allium sp. by a molecular docking method. Several 3D molecule structures of the highest flavonoids from Allium sp., including quercetin, kaempferol, isorhamnetin, myricetin, fisetin, morin, isoquercetin, quercitrin, spiraeoside, and quercetin-3,4-O-diglucoside were obtained from the PubChem database. Meanwhile, the FLT3 receptor complex with gilteritinib 3D structure was obtained from the RCSB PDB database. All compound properties were assessed using Swiss-ADME. FLT3 receptor prepared using Discovery Studio 2019. Meanwhile, all flavonoids' energy as ligands is minimized using PyRx 0.8 software. The specific docking was performed using Autodock Vina integrated with PyRyx v 0.8 software and visualized using Discovery Studio 2019, and several parameters of the docking data were analyzed. All flavonoids show favorable drug-likeness and pharmacokinetics properties apart from four quercetin derivatives. Meanwhile, the molecular docking result shows that Quercetin, kaempferol, isoquercetin, quercitrin, spiraeoside, and quercetin-3,4-O-diglucoside have inhibitory potential against FLT3 receptors because they share several same binding sites as control. They also have a fairly high binding affinity compared to the other compounds tested. Molecular dynamic simulation result demonstrates a considerably stable complex. It is estimated that quercetin and kaempferol from Allium sp. have the potential to be used as therapeutic drugs against AML.
... FMS-like tyrosine kinase 3 are membrane bound receptors with two common mutated forms observed in various types of leukemia (Cheng et al., 2018). Internal Tandem Duplication (ITD), present within the juxtamembrane domain of FLT-3 proteins, is most frequently observed in AML (30%) (Cheng et al., 2018). ...
... FMS-like tyrosine kinase 3 are membrane bound receptors with two common mutated forms observed in various types of leukemia (Cheng et al., 2018). Internal Tandem Duplication (ITD), present within the juxtamembrane domain of FLT-3 proteins, is most frequently observed in AML (30%) (Cheng et al., 2018). On the other hand, Missense point mutations, found in the tyrosine kinase domain, are more common in ALL (Cheng et al., 2018). ...
... Internal Tandem Duplication (ITD), present within the juxtamembrane domain of FLT-3 proteins, is most frequently observed in AML (30%) (Cheng et al., 2018). On the other hand, Missense point mutations, found in the tyrosine kinase domain, are more common in ALL (Cheng et al., 2018). Mutated FLT-3 proteins are involved in activating several signaling pathways, for example MAPK/ERK and STAT5, and thus indicate a higher risk of developing leukemia as well as a worse prognosis (Cheng et al., 2018). ...
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... Mutations in the genes CD274 (coding for PD-L1) and Lyn are of interest, as the importance of these genes in CLL development was shown both in patients and in the Eµ-TCL1 mouse model [36][37][38][39]. Other genes of interest are Flt3 and Atr, which were shown to be upregulated and to have a pathological role in CLL and other leukemias [40][41][42][43]. Future follow-up work will be necessary to explore the relevance and underlying mechanism of these or other mutated genes for leukemia development in the Eµ-TCL1 mouse model, and to estimate the usefulness of TCL1 tumors harboring these mutations as preclinical models for CLL. ...
Chronic lymphocytic leukemia (CLL) is a B-cell malignancy mainly occurring at an advanced age with no single major genetic driver. Transgenic expression of TCL1 in B cells leads after a long latency to a CLL-like disease in aged Eµ- TCL1 mice suggesting that TCL1 overexpression is not sufficient for full leukemic transformation. In search for secondary genetic events and to elucidate the clonal evolution of CLL, we performed whole exome and B-cell receptor sequencing of longitudinal leukemia samples of Eµ- TCL1 mice. We observed a B-cell receptor stereotypy, as described in patients, confirming that CLL is an antigen-driven disease. Deep sequencing showed that leukemia in Eµ- TCL1 mice is mostly monoclonal. Rare oligoclonality was associated with inability of tumors to develop disease upon adoptive transfer in mice. In addition, we identified clonal changes and a sequential acquisition of mutations with known relevance in CLL, which highlights the genetic similarities and therefore, suitability of the Eµ- TCL1 mouse model for progressive CLL. Among them, a recurrent gain of chromosome 15, where Myc is located, was identified in almost all tumors in Eµ- TCL1 mice. Interestingly, amplification of 8q24, the chromosomal region containing MYC in humans, was associated with worse outcome of patients with CLL.
... It has been demonstrated that FLT3-p.Asp835Tyr is associated with FLT3 increased expression in AML samples 14 . Consistently, we observed an increase in FLT3 expressing cells during disease progression and a higher frequency of cells with activated FLT3 gene module in T3. ...
Disease progression of myeloproliferative neoplasms is the result of increased genomic complexity. Since the ability to predict disease evolution is crucial for clinical decisions, we studied single-cell genomics and transcriptomics of CD34-positive cells from a primary myelofibrosis (PMF) patient who progressed to acute myeloid leukemia (AML) while receiving Ruxolitinib. Single-cell genomics allowed the reconstruction of clonal hierarchy and demonstrated that TET2 was the first mutated gene while FLT3 was the last one. Disease evolution was accompanied by increased clonal heterogeneity and mutational rate, but clones carrying TP53 and FLT3 mutations were already present in the chronic phase. Single-cell transcriptomics unraveled repression of interferon signaling suggesting an immunosuppressive effect exerted by Ruxolitinib. Moreover, AML transformation was associated with a differentiative block and immune escape. These results suggest that single-cell analysis can unmask tumor heterogeneity and provide meaningful insights about PMF progression that might guide personalized therapy.
