Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019214 (hepatosplenomegaly)
 4,408 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mer (MerTK) is a receptor tyrosine kinase important in platelet aggregation, as well as macrophage cytokine secretion and clearance of apoptotic cells. Mer is not normally expressed in thymocytes or lymphocytes; however, ectopic Mer RNA transcript and protein expression is found in a subset of acute lymphoblastic leukemia cell lines and patient samples, suggesting a role in leukemogenesis. To investigate the oncogenic potential of Mer in vivo, we created a transgenic mouse line (Mer(Tg)) that expresses Mer in the hematopoietic lineage under control of the Vav promoter. Ectopic expression and activation of the transgenic Mer protein was demonstrated in lymphocytes and thymocytes of the Mer(Tg) mice. At 12-24 months of age, greater than 55% of the Mer(Tg) mice, compared to 12% of the wild type, developed adenopathy, hepatosplenomegaly, and circulating lymphoblasts. Histopathological analysis and flow cytometry were consistent with T-cell lymphoblastic leukemia/lymphoma. Mer may contribute to leukemogenesis by activation of Akt and ERK1/2 anti-apoptotic signals, which were upregulated in Mer(Tg) mice. Additionally, a significant survival advantage was noted in Mer(Tg) lymphocytes compared to wild-type lymphocytes after dexamethasone treatment. These data suggest that Mer plays a cooperative role in leukemogenesis and may be an effective target for biologically based leukemia/lymphoma therapy.
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PMID:Lymphoblastic leukemia/lymphoma in mice overexpressing the Mer (MerTK) receptor tyrosine kinase. 1665 42

Aggressive natural killer-cell leukaemia (ANKL) is a rare type of disease with fulminant course and poor outcome. The disease is more prevalent among Asians than in other ethnic groups and shows strong association with Epstein-Barr virus (EBV) and P-glycoprotein (P-gp) expression associated with multidrug resistance. Here we present a case of a 47 year old Caucasian female with a prior medical history of azathioprine treated ulcerative colitis who developed EBV-negative form of ANKL. The patient presented with hepatosplenomegaly, fever and nausea with peripheral blood and bone marrow infiltration with up to 70% of atypical lymphoid cells positive for cCD3, CD2, CD7, CD56, CD38, CD45, TIA1 and granzyme B, and negative for sCD3, CD4, CD5, CD8, CD34 and CD123 indicative of ANKL. Neoplastic CD56(+) NK-cells showed high level of P-glycoprotein expression and activity, but also strong expression of phosphorylated extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) MAP kinase. The patient was treated with an intensive polychemotherapy regimen designed for treatment of acute lymphoblastic leukaemia, but one month after admission developed sepsis, coma and died of cardiorespiratory arrest. We present additional evidence that, except for the immunophenotype, leukaemic NK-cells resemble normal NK-cells in terms of P-gp functional capacity and expression of phosphorylated ERK1/2 signalling molecule. In that sense drugs that block P-glycoprotein activity and activated signalling pathways might represent new means for targeted therapy.
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PMID:Epstein-Barr virus-negative aggressive natural killer-cell leukaemia with high P-glycoprotein activity and phosphorylated extracellular signal-regulated protein kinases 1 and 2. 2308 5