Search

Isochromosome 20q- (i(20q-)), as a rare reproducible chromosomal anomaly formed on the basis of 20q-, has not been commonly reported. Due to the rarity of this karyotypic anomaly, the bone marrow morphological characteristics of the patients with i(20q-) have not been clarified until now. In this study, the bone marrow cell morphology from MDS patients with isolated i(20q-), isolated 20q-, and normal karyotype was retrospectively compared and statistically analyzed. The results indicated that the isolated i(20q-) was mostly detected in MDS-MLD patients. The frequency and proportion dysplasia of cytoplasmic vacuolization in erythoid cells and small or unusually large size in myeloid cells of isolated i(20q-) MDS patients were significantly higher than those of normal karyotype MDS patients respectively (P < 0.05); the frequency and proportion dysplasia of decreased granules/agranularity in myeloid cells of isolated i(20q-) MDS patients were higher than those of isolated 20q- MDS patients (P < 0.05). The incidence of some specific morphological manifestations, such as deeply lobulated and hyperlobulated megakaryocytes and hypogranular and vacuolized eosinophils, may be an important morphological implication for the anomaly of isolated i(20q-). These morphological features of dysplasia may be helpful in distinguishing MDS with isolated i(20q-) from those with isolated 20q- and normal karyotype.

The polycomb group BMI1 is proved to be crucial in malignant myeloid progression. However, the underlying mechanism of the action of BMI1 in myeloid malignant progression was not well characterized. In this study, we found that the patients of both myelodysplastic syndromes and chronic myeloid leukaemia with BMI1 overexpression had a higher risk in malignant myeloid progression. In vitro gene transfection studies showed that BMI1 inhibited cell myeloid and erythroid differentiation induced by 12-O-tetradecanoyl phorbol-13-acetate (TPA) and histone deacetylase inhibitor sodium butyrate respectively. BMI1 also resisted apoptosis induced by arsenic trioxide. Moreover, the transcript levels of Runx1 and Pten were down-regulated in Bmi1-transfected cells in company with histone deacetylation modification. By using chromatin immunoprecipitation (ChIP) collaborated with secondary generation sequencing and verified by ChIP-PCR, we found that BMI1 directly bound to the promoter region of Zmym3, which encodes a component of histone deacetylase-containing complexes. In addition, as one of the downstream target genes of this complex, c-fos was activated with increasing histone acetylation when ZMYM3 was suppressed in the Bmi1-transfected cells. These results suggested that BMI1 may reprogramme the histone acetylation profile in multiple genes through either indirect or direct binding effects which probably contributes to the malignant progression of myeloid progenitor cells., (© 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Besides cytopenia, dysplasia is crucial characteristic of MDS-RA. To summarize the morphological features that contribute to the diagnosis of MDS-RA, 48 RA patients with abnormal karyotype were analyzed for the features of morphological and cytogenetical abnormalities and the relationships between them. 46 MDS-RA patients with normal karyotype and 207 patients with non-MDS anemia were enrolled into control groups. More conspicuous and diverse dysplasia can be found in abnormal karyotype MDS-RA than those in control groups (P<0.05). Apparent dysplasia in granulocyte and megakaryocytoid lineages may provide valuable evidence for the diagnosis. Dysplasia occurred more frequently in patients with severe chromosome abnormalities.

Delta-like-1 (Dlk1, also Pref-1), a transmembrane and secreted protein, is a member of the epidermal growth factor-like family, homologous to Notch/Delta/Serrate. We found that the expression of Dlk1 was up-regulated in CD34+ cells from patients with myelodysplastic syndrome (MDS) by analyzing the gene expression profiles determined by microarray. The expression levels of Dlk1 mRNA frequently observed higher in the bone marrow mononuclear cells of MDS patients was confirmed by real-time RT-PCR. Forced expression of Dlk1 in transfected K562 cells enhanced proliferation, affected apoptosis induced by As2O3, and also influenced cell cycle induced by 12-O-tetra decanoylphorbol-acetate (TPA). By using the same experimental system we found that forced expression of Dlk1 increased the mRNA levels of HES1. It also inhibited p38 phosphorylation in transfected K562 cells treated with TPA. These results warrant further investigation of the role of Dlk1 in abnormal hematopoiesis in MDS.

CCAAT/enhancer binding proteins (C/EBPs) are a family of transcription factors that have been implicated in diverse cellular functions such as cellular differentiation and proliferation, and inflammatory processes. C/EBPzeta, also known as GADD153, CHOP10, and DDIT3 has been found associated with the development of myxoid liposarcoma and the progression of melanoma. To investigate the correlation of C/EBPzeta transcript levels with the development of leukemia, samples from 187 patients with myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML) were examined for C/EBPzeta mRNA using real-time quantitative PCR (RQ-PCR). RQ-PCR analysis demonstrated the median levels of C/EBPzeta were significantly decreased in MDS, AML, and CML patients compared with normal controls (1.40, 0.96, 2.60 versus 14.69, P<0.0001). Significant differences were also observed between patients with CML and with AML or MDS. These results suggest that the insufficient dosage of C/EBPzeta might be involved in the development of leukemia.

The gene expression pattern of bone marrow mononuclear cells (BMNCs) from 10 patients with myelodysplastic syndrome (MDS) was studied by two-color cDNA microarray techniques. To confirm the microarray results, a semiquantitative RT-PCR was performed to analyze gene expression in fifty additional MDS patients. Ninety-five genes were shown to be abnormally expressed in at least five MDS patients compared to normal controls, involving cell growth and differentiation regulation, cell cycle control, signaling and redox; such as thrombospondin 1, phosphatase and tensin homolog, MAD, DNA-damage-inducible transcript 3 (DDIT3), ets variant gene 1 (ETV1), and G1 to S phase transition 1. CD36 was also revealed up-regulated in 4 cases. MDS patients in early and advanced stages could be clustered into two distinct groups by hierarchical clustering, wherein a case with isolated thrombocytopenia and other RA patients were clustered into two subgroups. Consistent expression patterns of 3/5 (60%) genes were confirmed by semiquantitative RT-PCR. Further analysis showed the different transcript levels of RNAHP, DDIT3 in patients with MDS in different stages, AML, and normal controls. Meanwhile, the different significance of RNAHP and ETV1 expression was revealed between RA and untypical anaplastic anemia, iron deficiency anemia, and megaloblastic anemia patients. We propose that the technology of microarray may reveal the intrinsic molecular features and the expression levels of RNAHP, DDIT3, and ETV1 may provide useful markers for the diagnosis of MDS.

Refractory thrombocytopenia (RTC) is an unusual subtype of myelodysplastic syndrome (MDS) that initially presents as chronic pure thrombocytopenia. Because of the lack of distinguishable dysplasia, RTC has often been misdiagnosed as idiopathic thrombocytopenic purpura. We describe the case of a patient with RTC and trisomy 8 for whom a bone marrow mononuclear cell (BMNC) gene expression profile was obtained by means of a complementary DNA microarray analysis. Compared with the healthy control subject, the RTC patient differentially expressed 105 genes, of which 88 were down-regulated and 17 were up-regulated. The expression pattern of 16 genes, including those for RNA helicase-related protein (RNAHP), heat shock 105kD (HSP105B), interferon-related developmental regulator 1 (IFRD1), cyclin C (CCNC), and DNA-damage-inducible transcript 3 (DDIT3), which are usually seen in BMNCs from typical MDS patients, was observed in this case. However, this RTC patient exhibited an expression pattern distinct from that of other MDS patients. We suggest that RTC be classified as a subtype of MDS on the basis of its characteristic clinical-hematologic features and specific molecular basis.

Objective: To study telomerase activity (TA) and its variation in bone marrow mononuclear cells from patients with myelodysplastic syndrome (MDS) at different stages in comparison with normal bone marrow cells and leukemic cells., Methods: The TA was semi-quantitatively determined in mononuclear cells from 20 normal bone marrow samples, 21 patients with MDS at different stages and 32 cases of acute leukemia by using a polymerase chain reaction-enzyme linked immuno-sorben assay (PCR-ELISA) kit., Results: The TA in normal bone marrow cells was in the range of 0 to 0.3 units (U) with a mean of 0.11 +/- 0.08 U. Among them, 3 samples were considered positive in accordance with the standard recommended by the kit's pamphlet. In bone marrow cells from patients with acute leukemia, the TA was ranging from 0 to 0.96 U with a mean value of 0.42 +/- 0.26 U. The positive rate was 78.1% which was significantly different from that in normal bone marrow (BM) (P < 0.01). In case of myelodysplastic syndrome, the average level of TA was 0.27 +/- 0.19 U (ranging from 0 to 0.97 U) with a positive rate of 66.7%. In comparison with normal BM cells, the difference was significant (P < 0.05). Particularly, the MDS high-risk subgroup exhibited a significantly higher activity of telomerase (P < 0.05). In comparison with INT-1 and INT-2 subgroups in MDS patients based on international prognostic scoring system (IPPS), the difference in TA was also significant (P < 0.05). The abnormality in cell karyotype was not correlated with TA., Conclusion: The normal bone marrow cells demonstrate TA at a marginal level while a remarkably increasing level may be seen in acute leukemia patients. The BM cells from MDS patients display a moderate TA among which the high risk MDS subgroup with a poor prognostic IPPS score exhibited markedly higher TA.

The myelodysplastic syndromes (MDS) comprise a heterogeneous group of malignant neoplasms with distinctive clinicopathological features. Currently, there is no specific approach for the treatment of MDS. Here, we report that bortezomib (BTZ), a proteasome inhibitor that has been used to treat plasma cell myeloma, induced G2/M phase cycle arrest in the MDS cell line SKM-1 through upregulation of Wee1, a negative regulator of G2/M phase transition. Treatment by BTZ led to reduced SKM-1 cell viability as well as increased apoptosis and autophagy. The BTZ-induced cell death was associated with reduced expression of p-ERK. To elucidate the implications of downregulation of p-ERK, we established the BTZ resistant cell line SKM-1R. Our data show that resistance to BTZ-induced apoptosis could be reversed by the MEK inhibitors U0126 or PD98059. Our results suggest that MAPK pathway may play an important role in mediating BTZ resistance. [ABSTRACT FROM AUTHOR]