Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in the receptor tyrosine kinase (RTK/RAS) signalling pathway frequently provide a proliferative signal in myeloid malignancies. However, the role of RASSF1A, SHP-1 and SOCS-1, negative regulators of RTK/RAS signalling, has not been extensively investigated in the myelodysplastic syndromes (MDS) or acute myeloid leukaemia (AML). This study employed methylation-specific polymerase chain reaction (MS-PCR) to determine if aberrant promotor methylation of RASSF1A, SHP-1 and SOCS-1 is involved in the pathogenesis of myeloid malignancies. Patients with MDS (n = 107), AML (n = 154) and juvenile myelomonocytic leukaemia (JMML, n = 5) were investigated, together with 15 normal controls. Primers were located in the promotor region of each gene as well as within exon 2 of SOCS-1. Methylation of RASSF1A was found in five of 55 (9%) MDS cases, but not in any of 57 AML cases studied. RASSF1A methylation was present in one case (20%) of JMML. SHP-1 methylation was present in 13 of 121 (11%) AML cases but was not found in MDS or JMML. SOCS-1 promoter methylation was present in eight of 74 (11%) MDS patients but was not seen in JMML or AML. Importantly, RAS mutations and RASSF1A and SOCS-1 methylation were mutually exclusive indicating that approximately 30% of MDS cases had a defect of the RTK/RAS pathway and its negative regulation. Finally, SOCS-1 exon 2 methylation may not be pathogenetically relevant, since it was detected in samples from normal individuals and did not correlate with promotor methylation.
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PMID:Aberrant methylation of the negative regulators RASSFIA, SHP-1 and SOCS-1 in myelodysplastic syndromes and acute myeloid leukaemia. 1580 56

To study the role of SHP-1 methylation in the pathogenesis of myelodysplastic syndromes (MDS), we detect the methylation status of SHP-1 promoter and STAT3 phosphorylation of MDS patients by the methylation-specific PCR and Western blotting, respectively. It is found that the methylation rate of SHP-1 promoter of high-risk MDS patients (69.2%) was higher than that of the low-risk MDS patients (21.4%) (P=0.001). The expression rate of STAT3 phosphorylated protein of high-risk group was higher (66.7%), when compared with that of the low-risk group (18.2%) (P=0.0001). Correlation analysis showed that the methylation status of SHP-1 promoter is positive correlated with the expression of phosphorylated STAT3 in MDS patient (P<0.001, r=0.55). Interestingly, in high-risk group, the Kaplan-Meier analysis showed that the 3-year overall survival rate of high-risk MDS patients with SHP-1 methylation was lower than that of patient without SHP-1 methylation (25% vs. 61%) (P=0.033). In summary, it is indicated that the SHP-1 methylation plays important role in the pathogenesis of MDS via activating the JAK/STAT pathway probably and the methylation of SHP-1 promoter is a useful prognostic factor for high-risk MDS patient, with the characteristic of higher methylation lower survival rate.
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PMID:Hypermethylation of SHP-1 promoter in patient with high-risk myelodysplastic syndrome and it predicts poor prognosis. 2225 37

Myelodysplastic syndromes (MDSs) are clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis. Anemia is the defining cytopenia of MDS patients, yet the molecular mechanisms for dyserythropoiesis in MDSs remain to be fully defined. Recent studies have revealed that heterozygous loss-of-function mutation of DNA dioxygenase TET2 is 1 of the most common mutations in MDSs and that TET2 deficiency disturbs erythroid differentiation. However, mechanistic insights into the role of TET2 on disordered erythropoiesis are not fully defined. Here, we show that TET2 deficiency leads initially to stem cell factor (SCF)-dependent hyperproliferation and impaired differentiation of human colony-forming unit-erythroid (CFU-E) cells, which were reversed by a c-Kit inhibitor. We further show that this was due to increased phosphorylation of c-Kit accompanied by decreased expression of phosphatase SHP-1, a negative regulator of c-Kit. At later stages, TET2 deficiency led to an accumulation of a progenitor population, which expressed surface markers characteristic of normal CFU-E cells but were functionally different. In contrast to normal CFU-E cells that require only erythropoietin (EPO) for proliferation, these abnormal progenitors required SCF and EPO and exhibited impaired differentiation. We termed this population of progenitors "marker CFU-E" cells. We further show that AXL expression was increased in marker CFU-E cells and that the increased AXL expression led to increased activation of AKT and ERK. Moreover, the altered proliferation and differentiation of marker CFU-E cells were partially rescued by an AXL inhibitor. Our findings document an important role for TET2 in erythropoiesis and have uncovered previously unknown mechanisms by which deficiency of TET2 contributes to ineffective erythropoiesis.
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PMID:TET2 deficiency leads to stem cell factor-dependent clonal expansion of dysfunctional erythroid progenitors. 3049 69