scholarly journals FMS-like Tyrosine Kinase 3/FLT3: From Basic Science to Clinical Implications

2019 ◽  
Vol 99 (3) ◽  
pp. 1433-1466 ◽  
Author(s):  
Julhash U. Kazi ◽  
Lars Rönnstrand
Keyword(s):  
Signal Transduction ◽  
Tyrosine Kinase ◽  
Myeloid Leukemia ◽  
Current Knowledge ◽  
Biological Effects ◽  
Acquired Resistance ◽  
Cell Proliferation And Differentiation ◽  
Functional Aspects ◽  
Proliferation And Differentiation ◽  
Targeted Inhibition

FMS-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase that is expressed almost exclusively in the hematopoietic compartment. Its ligand, FLT3 ligand (FL), induces dimerization and activation of its intrinsic tyrosine kinase activity. Activation of FLT3 leads to its autophosphorylation and initiation of several signal transduction cascades. Signaling is initiated by the recruitment of signal transduction molecules to activated FLT3 through binding to specific phosphorylated tyrosine residues in the intracellular region of FLT3. Activation of FLT3 mediates cell survival, cell proliferation, and differentiation of hematopoietic progenitor cells. It acts in synergy with several other cytokines to promote its biological effects. Deregulated FLT3 activity has been implicated in several diseases, most prominently in acute myeloid leukemia where around one-third of patients carry an activating mutant of FLT3 which drives the disease and is correlated with poor prognosis. Overactivity of FLT3 has also been implicated in autoimmune diseases, such as rheumatoid arthritis. The observation that gain-of-function mutations of FLT3 can promote leukemogenesis has stimulated the development of inhibitors that target this receptor. Many of these are in clinical trials, and some have been approved for clinical use. However, problems with acquired resistance to these inhibitors are common and, furthermore, only a fraction of patients respond to these selective treatments. This review provides a summary of our current knowledge regarding structural and functional aspects of FLT3 signaling, both under normal and pathological conditions, and discusses challenges for the future regarding the use of targeted inhibition of these pathways for the treatment of patients.

scholarly journals An overview on the role of FLT3-tyrosine kinase receptor in acute myeloid leukemia: biology and treatment

2012 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Tiziana Grafone ◽  
Michela Palmisano ◽  
Chiara Nicci ◽  
Sergio Storti
Keyword(s):  
Acute Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Signaling Pathways ◽  
Myeloid Leukemia ◽  
Molecular Therapy ◽  
Tyrosine Kinase Receptor ◽  
Hematopoietic Stem ◽  
Downstream Signaling ◽  
Proliferation And Differentiation ◽  
Acute Myeloid

Hematopoiesis, the process by which the hematopoietic stem cells and progenitors differentiate into blood cells of various lineages, involves complex interactions of transcription factors that modulate the expression of downstream genes and mediate proliferation and differentiation signals. Despite the many controls that regulate hematopoiesis, mutations in the regulatory genes capable of promoting leukemogenesis may occur. The <em>FLT3</em> gene encodes a tyrosine kinase receptor that plays a key role in controlling survival, proliferation and differentiation of hematopoietic cells. Mutations in this gene are critical in causing a deregulation of the delicate balance between cell proliferation and differentiation. In this review, we provide an update on the structure, synthesis and activation of the FLT3 receptor and the subsequent activation of multiple downstream signaling pathways. We also review activating FLT3 mutations that are frequently identified in acute myeloid leukemia, cause activation of more complex downstream signaling pathways and promote leukemogenesis. Finally, FLT3 has emerged as an important target for molecular therapy. We, therefore, report on some recent therapies directed against it.

scholarly journals Localization and significance of pp55, a gastric mucosal membrane protein with tyrosine kinase activity

1998 ◽  
Vol 274 (5) ◽  
pp. G863-G870 ◽  
Author(s):  
Adhip P. N. Majumdar ◽  
James R. Goldenring
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Mucosal Cell ◽  
Mucous Cells ◽  
Tyrosine Kinase Activity ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Mucosal Cell Proliferation

In Fischer 344 rats, induction of gastric mucosal proliferative activity, whether the result of aging or injury or occurring after administration of epidermal growth factor, gastrin, or bombesin, is associated with a rise in tyrosine kinase activity and tyrosine phosphorylation of several mucosal proteins, including a protein with a molecular mass of 53–55 kDa. We hypothesized that this phosphotyrosine membrane protein (referred to as pp55) may play a role in regulating gastric mucosal cell proliferation and differentiation. Purification and subsequent immunoprecipitation studies now show that pp55 is a tyrosine kinase. In addition, the enzyme activity in the gastric mucosa is found to be fourfold higher in aged rats than in young rats. Incubation of gastric mucosal membranes with transforming growth factor-α (2 × 10−8 M) stimulates tyrosine kinase activity of pp55. Immuolocalization studies reveal that pp55 immunoreactivity is predominantly present in mucous cells that are located just above the proliferative zone and spasmolytic peptide-immunoreactive mucous neck cells. Tyrosine kinase activity as well as expression of pp55 are also greatly increased in the gastric mucosa after hypertonic saline-induced injury, a condition that results in stimulation of surface mucosal cell proliferation and differentiation. Our current data suggest that pp55 is a tyrosine kinase, likely localized to pre-surface cells. The presence of pp55 in pre-surface mucous cells and the expression and tyrosine kinase activity of this protein, which can be stimulated during mucosal cell proliferation and differentiation, strongly suggest a role for pp55 in differentiation of gastric surface mucous cells.

scholarly journals MicroRNAs in brain development and cerebrovascular pathophysiology

2019 ◽  
Vol 317 (1) ◽  
pp. C3-C19 ◽  
Author(s):  
Qingyi Ma ◽  
Lubo Zhang ◽  
William J. Pearce
Keyword(s):  
Brain Development ◽  
Synapse Formation ◽  
Current Knowledge ◽  
Great Promise ◽  
Ischemic Brain ◽  
Neural Lineage ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
And Function

MicroRNAs (miRNAs) are a class of highly conserved non-coding RNAs with 21–25 nucleotides in length and play an important role in regulating gene expression at the posttranscriptional level via base-paring with complementary sequences of the 3′-untranslated region of the target gene mRNA, leading to either transcript degradation or translation inhibition. Brain-enriched miRNAs act as versatile regulators of brain development and function, including neural lineage and subtype determination, neurogenesis, synapse formation and plasticity, neural stem cell proliferation and differentiation, and responses to insults. Herein, we summarize the current knowledge regarding the role of miRNAs in brain development and cerebrovascular pathophysiology. We review recent progress of the miRNA-based mechanisms in neuronal and cerebrovascular development as well as their role in hypoxic-ischemic brain injury. These findings hold great promise, not just for deeper understanding of basic brain biology but also for building new therapeutic strategies for prevention and treatment of pathologies such as cerebral ischemia.

scholarly journals Effects of RAC1 on Proliferation of Hen Ovarian Prehierarchical Follicle Granulosa Cells

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1589
Author(s):  
Thobela Louis Tyasi ◽  
Xue Sun ◽  
Xuesong Shan ◽  
Simushi Liswaniso ◽  
Ignatius Musenge Chimbaka ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Biological Effects ◽  
Expression Levels ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Mrna And Protein Expression ◽  
Chicken Ovary ◽  
New Evidence ◽  
Follicle Selection

RAC1 belongs to the small G protein Rho subfamily and is implicated in regulating gene expression, cell proliferation and differentiation in mammals and humans; nevertheless, the function of RAC1 in growth and development of hen ovarian follicles is still unclear. This study sought to understand the biological effects of RAC1 on granulosa cell (GC) proliferation and differentiation of hen ovarian prehierarchical follicles. Firstly, our results showed expression levels of RAC1 mRNA in the follicles with diameters of 7.0–8.0 mm, 6.0–6.9 mm and 1.0–3.9 mm were greater than other follicles (p < 0.05). The RAC1 protein was mainly expressed in oocyte and its around GCs and stromal tissues of the prehierarchical follicles by immunohistochemistry. Further investigation revealed the RAC1 gene remarkably enhanced the mRNA and protein expression levels of FSHR (a marker of follicle selection), CCND2 (a marker of cell-cycle progression and GC differentiation), PCNA (a marker of GC proliferation), StAR and CYP11A1 (markers of GC differentiation and steroidogenesis) (p < 0.05). Furthermore, our data demonstrated siRNA interference of RAC1 significantly reduced GC proliferation (p < 0.05), while RAC1 gene overexpression enhanced GC proliferation in vitro (p < 0.05). Collectively, this study provided new evidence that the biological effects of RAC1 on GC proliferation, differentiation and steroidogenesis of chicken ovary follicles.

scholarly journals Physiological and pathological implications of retinoid action in the endometrium

2018 ◽  
Vol 236 (3) ◽  
pp. R169-R188 ◽  
Author(s):  
Yanwen Jiang ◽  
Lu Chen ◽  
Robert N Taylor ◽  
Chunjin Li ◽  
Xu Zhou
Keyword(s):  
Current Knowledge ◽  
Critical Factor ◽  
Reproductive Age ◽  
Pelvic Cavity ◽  
Retinoid Signaling ◽  
Retinoid Metabolism ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Blastocyst Implantation ◽  
Gynecological Disease

Retinol (vitamin A) and its derivatives, collectively known as retinoids, are required for maintaining vision, immunity, barrier function, reproduction, embryogenesis and cell proliferation and differentiation. Despite the fact that most events in the endometrium are predominantly regulated by steroid hormones (estrogens and progesterone), accumulating evidence shows that retinoid signaling is also involved in the development and maintenance of the endometrium, stromal decidualization and blastocyst implantation. Moreover, aberrant retinoid metabolism seems to be a critical factor in the development of endometriosis, a common gynecological disease, which affects up to 10% of reproductive age women and is characterized by the ectopic localization of endometrial-like tissue in the pelvic cavity. This review summarizes recent advances in research on the mechanisms and molecular actions of retinoids in normal endometrial development and physiological function. The potential roles of abnormal retinoid signaling in endometriosis are also discussed. The objectives are to identify limitations in current knowledge regarding the molecular actions of retinoids in endometrial biology and to stimulate new investigations toward the development potential therapeutics to ameliorate or prevent endometriosis symptoms.

Growth factor receptor-bound protein 14: a potential new gene associated with oocyte competence

Zygote ◽  
2013 ◽  
Vol 22 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Paulo Roberto Antunes Rosa ◽  
Rodrigo Camponogara Bohrer ◽  
Matheus Pedrotti De Cesaro ◽  
Karina Gutierrez ◽  
Rogério Ferreira ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Mrna Expression ◽  
Growth Factor Receptor ◽  
Follicular Development ◽  
Antral Follicle ◽  
Protein Family ◽  
Oocyte Competence ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
New Gene

SummaryThe Grb14 protein is a member of the Grb7 protein family. This protein family acts by binding to tyrosine kinase receptors, promoting cell proliferation and differentiation. There is evidence of the involvement of tyrosine kinase factors in the bovine oocyte maturation process. However, Grb14 has not been studied for bovine cumulus–oocyte complexes (COCs). The aim of the present study was to characterize Grb14 mRNA expression in bovine COCs during follicular development. Furthermore, we demonstrated that the expression of Grb14 mRNA is not regulated by estradiol. mRNA expression of Grb14 was assessed in 480 COCs from follicles of different sizes (1–3, 4–6, 6–8 or >8 mm) by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Grb14 mRNA expression decreased in COCs throughout follicular growth (P < 0.05). The role of estradiol in the expression of Grb14 mRNA in COCs was studied. Grb14 mRNA abundance did not differ in COCs cultured in the presence or absence of 17β-estradiol or fulvestrant. In conclusion, we showed that Grb14 mRNA is downregulated in COCs during antral follicle development, a finding that suggests a role for Grb14 in oocyte competence.

scholarly journals FLT3 Tyrosine Kinase Inhibitors for the Treatment of Fit and Unfit Patients with FLT3-Mutated AML: A Systematic Review

2021 ◽  
Vol 22 (11) ◽  
pp. 5873
Author(s):  
Michael Loschi ◽  
Rinzine Sammut ◽  
Edmond Chiche ◽  
Thomas Cluzeau
Keyword(s):  
Acute Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Tyrosine Kinase Inhibitors ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Current Knowledge ◽  
Complete Response ◽  
Resistance Mechanisms ◽  
Current Lines ◽  
Acute Myeloid

FLT3-mutated acute myeloid leukemia accounts for around 30% of acute myeloid leukemia (AML). The mutation carried a poor prognosis until the rise of tyrosine kinase inhibitors (TKIs). New potent and specific inhibitors have successfully altered the course of the disease, increasing the complete response rate and the survival of patients with FLT3-mutated AML. The aim of this article is to review all the current knowledge on these game-changing drugs as well as the unsolved issues raised by their use for fit and unfit FLT3-mutated AML patients. To this end, we analyzed the results of phase I, II, III clinical trials evaluating FLT3-TKI both in the first-line, relapse monotherapy or in combination referenced in the PubMed, the American Society of Hematology, the European Hematology Association, and the Clinicaltrials.gov databases, as well as basic science reports on TKI resistance from the same databases. The review follows a chronological presentation of the different trials that allowed the development of first- and second-generation TKI and ends with a review of the current lines of evidence on leukemic blasts resistance mechanisms that allow them to escape TKI.

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