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Objective: To explore the effects and mechanisms of chidamide on the osteogenic differentiation of bone marrow mesenchymal stromal cells (MSC) from myelodysplastic syndromes (MDS)., Methods: MSC were isolated and cultured from bone marrow of MDS patients and healthy donors. CCK-8 assay was used to detect the effects of chidamide on the proliferation of MSC. The effects of chidamide on the activity of histone deacetylase (HDAC) in MSC was measured by a fluorescence assay kit and Western blot. Alkaline phosphatase (ALP) activity was detected on day 3 and calcium nodule formation was observed by Alizarin Red staining on day 21 after osteogenic differentiation. The expression of early and late osteogenic genes was detected on day 7 and day 21, respectively. RT-PCR and Western blot were used to detect the effects of chidamide on mRNA and protein expression of RUNX2 which is the key transcription factor during osteogenesis., Results: As the concentration of chidamide increased, the proliferation of MSC was inhibited. However, at a low concentration (1 μmol/L), chidamide had no significant inhibitory effect on MSC proliferation but significantly inhibited HDAC activity. In MSC from both MDS patients and healthy donors, chidamide (1 μmol/L) significantly increased ALP activity, calcium nodule formation, thereby mRNA expression of osteogenic genes, and restored the reduced osteogenic differentiation ability of MDS-MSC compared to normal MSC. Mechanistic studies showed that the osteogenic-promoting effect of chidamide may be related to the upregulation of RUNX2 ., Conclusion: Chidamide can inhibit HDAC activity in MSC, upregulate the expression of the osteogenic transcription factor RUNX2 , and promote the osteogenic differentiation of MDS-MSC.

Objective: To analyze the influencing factors of iron metabolism assessment in patients with myelodysplastic syndrome. Methods: MRI and/or DECT were used to detect liver and cardiac iron content in 181 patients with MDS, among whom, 41 received regular iron chelation therapy during two examinations. The adjusted ferritin (ASF) , erythropoietin (EPO) , cardiac function, liver transaminase, hepatitis antibody, and peripheral blood T cell polarization were detected and the results of myelofibrosis, splenomegaly, and cyclosporine were collected and comparative analyzed in patients. Results: We observed a positive correlation between liver iron concentration and ASF both in the MRI group and DECT groups ( r =0.512 and 0.606, respectively, P <0.001) , only a weak correlation between the heart iron concentration and ASF in the MRI group ( r =0.303, P <0.001) , and no significant correlation between cardiac iron concentration and ASF in the DECT group ( r =0.231, P =0.053) . Moreover, transfusion dependence in liver and cardiac [MRI group was significantly associated with the concentration of iron in: LIC: (28.370±10.706) mg/g vs (7.593±3.508) mg/g, t =24.30, P <0.001; MIC: 1.81 vs 0.95, z =2.625, P <0.05; DECT group: liver VIC: (4.269±1.258) g/L vs (1.078±0.383) g/L, t =23.14, P <0.001: cardiac VIC: 1.69 vs 0.68, z =3.142, P <0.05]. The concentration of EPO in the severe iron overload group was significantly higher than that in the mild to moderate iron overload group and normal group ( P <0.001) . Compared to the low-risk MDS group, the liver iron concentration in patients with MDS with cyclic sideroblasts (MDS-RS) was significantly elevated [DECT group: 3.80 (1.97, 5.51) g/L vs 1.66 (0.67, 2.94) g/L, P =0.004; MRI group: 13.7 (8.1,29.1) mg/g vs 11.6 (7.1,21.1) mg/g, P =0.032]. Factors including age, bone marrow fibrosis, splenomegaly, T cell polarization, use of cyclosporine A, liver aminotransferase, and hepatitis antibody positive had no obvious effect on iron metabolism. Conclusion: There was a positive correlation between liver iron concentration and ASF in patients with MDS, whereas there was no significant correlation between cardiac iron concentration and ASF. Iron metabolism was affected by transfusion dependence, EPO concentration, and RS.

MDS development is a dynamic process during which the accumulation of somatic mutations leads to specific malignant evolution. To elucidate the differential roles of gene mutations in typical MDS, we used targeted sequencing to investigate clonal patterns from 563 patients and focused on cases (199/563 cases) with initial mutations (ASXL1, DNMT3A and TET2) at MDS diagnosis. The consistency of frequency and distribution in patients with or without aberrant chromosomes suggested early events of these initial mutations. Some additional driver mutations (SF3B1, U2AF1 or RUNX1) played roles to keep the basic disease features, or give rise to different phenotypes (BCOR, EZH2 or TP53) in individual patients. Notably, analysis in paired samples before and after MDS progression showed that the mutations identified as last events (involving active signaling, myeloid transcription or tumor suppressor) seemed necessary for MDS development to be AML. Last mutations can exist at MDS diagnosis, or emerge at AML transformation, and involve a small group of genes. Single-allele CEBPA mutations and diverse TP53 mutations were checked as the most common last event mutations. Considering the necessity of last event mutations and limited gene involvement in AML transformations, it is possible to validate a small group of last events involved mutations to develop some new strategies to block MDS progression.

Background: Hyaluronan (HA), a major component of the extracellular matrix, has been proven to play a crucial role in tumor progression. However, it remains unknown whether HA exerts any effects in myelodysplastic syndromes (MDS)., Methods: A total of 82 patients with MDS and 28 healthy donors were investigated in this study. We firstly examined the bone marrow (BM) serum levels of HA in MDS by radioimmunoassay. Then we determined HA production and hyaluronan synthase (HAS) gene expression in BM mesenchymal stromal cells (MSC) and mononuclear cells derived from MDS patients. Finally, we investigated the effects of HA on osteogenic differentiation of MSC., Results: The BM serum levels of HA was increased in higher-risk MDS patients compared to normal controls. Meanwhile, patients with high BM serum HA levels had significantly shorter median survival than those with low HA levels. Moreover, the HA levels secreted by MSC was elevated in MDS, especially in higher-risk MDS. In addition, HAS-2 mRNA expression was also up-regulated in higher-risk MDS-MSC. Furthermore, we found that MSC derived from MDS patients with high BM serum HA levels had better osteogenic differentiation potential. Moreover, MSC cultured in HA-coated surface presented enhanced osteogenic differentiation ability., Conclusions: Our results show that elevated levels of BM serum HA are related to adverse clinical outcome in MDS. Better osteogenic differentiation of MSC induced by HA may be implicated in the pathogenesis of MDS.

Objective: To investigate the inhibitory effect of decitabine (DAC) in various dosages on the proliferention of MDS-RAEB cell line MDS-L and its mechanism., Methods: LC-MS/MS method was used to test the blood DAC concentration of 2 groups of MDS patients being treated with DAC 20 and 15 mg/m 2 ×5 d. In according to the various blood DAC concentration levels, the MDS-L cells were treated with different DAC dosages for 24, 48, 72 and 96 h, respectively. The CCK-8 method was applied to determine the cell proliferation, the flow cytometry was used to analyze the cell cycle and cell apoptosis changes, the P15 INK4B DNA methylation status was measured by methylation specific PCR using EZ DNA Methylation-Gold Kit., Results: The blood DAC concentration of MDS patients treated with DAC 20 mg/m 2 ×5 d was 174.08±80.15(84.7-311) ng/ml, which was significantly higher than 89.87±32.94(43.2-165)ng/ml for the group treated with 15 mg/m 2 ×5 d (P=0.014). DAC could notably inhibit the proliferation of MDS-L cells, and the effect was in dose- and- time-dependent manner(r=0.786). However, when DAC concentration was ≥0.1 µg/ml, the proliferation inhibition rates were not significantly different between various dosages. After DAC treatment, MDS-L cells in G 1 phase increased notably, while cells in S phase decreased significantly. Also, the P15 INK4B DNA methylation status of MDS-L cells decreased after being treated with DAC for 96 h, but the difference was not significant between various dosages., Conclusion: DAC can significantly suppress MDS-L cell proliferation, block MDS-L cells in G 1 phase and induce the apoptosis at low concentration (0.1-0.2 µg/ml).

Erythroid apoptosis increases significantly in myelodysplastic syndrome (MDS) patients with iron overload, but the underlying mechanism is not fully clear. In this study, we aim to explore the effect of HIF-1a/ROS on erythroid apoptosis in MDS patients with iron overload. We found that iron overload injured cellular functions through up-regulating ROS levels in MDS/AML cells, including inhibited cell viability, increased cell apoptosis and blocked cell cycle at G0/G1 phase. Interestingly, overexpression of hypoxia inducible factor-1a (HIF-1a), which was under-expressed in iron overload models, reduced ROS levels and attenuated cell damage caused by iron overload in MDS/AML cells. And gene knockdown of HIF-1a got the similar results as iron overload in MDS/AML cells. Furthermore, iron overload caused high erythroid apoptosis was closely related with ROS in MDS patients. Importantly, the HIF-1a protein levels of erythrocytes elevated obviously after incubation with desferrioxamine (DFO) from MDS patients with iron overload, accompanied by ROS levels inhibited and erythroid apoptosis reduced. Taken together, our findings determine that the HIF-1a/ROS signaling pathway plays a key role in promoting erythroid apoptosis in MDS patients with iron overload., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Novel sequencing designs are necessary to supplement the recognized knowledge of myelodysplastic syndrome (MDS)-related genomic alterations. In this study, we sequenced 28 target genes in 320 Chinese MDS patients but obtained 77.2% of recall factors and 82.8% of genetic abnormalities (including karyotype abnormalities). In addition to known relationships among mutations, some specific chromosomal abnormalities were found to link to specific gene mutations. Trisomy 8 tended to be linked to U2AF1 and ZRSR2 mutations, and 20q- exhibited higher SRSF2/WT1 and U2AF1 mutation frequency. Chromosome 7 involvement accounted for up to 50% of RUNX1 mutations and 37.5% of SETBP1 mutations. Patients carrying a complex karyotype were prone to present TP53 mutations (36.1%). However, individuals with normal karyotypes rarely possessed mutations in the TP53, RUNX1 and U2AF1. Moreover, DNMT3A, TP53, SRSF2, STAG2, ROBO1/2 and WT1 predicted poor survival and high AML transformation. By integrating these predictors into international prognostic scoring system (IPSS) or revised IPSS, we built a set of mutation-based prognostic risk models. These models could layer different degrees of risk in patients more satisfactorily. In summary, this sequencing design was able to detect a number of gene mutations and could be used to stratify patients with varied prognostic risk.

Objective: To identify clinical and molecular signatures for predicting response to decitabine (DAC) in patients with myelodysplastic syndrome (MDS) and related neoplasms. Methods: The clinical characteristics of 109 patients with MDS and related neoplasms who were treated with DAC were analyzed retrospectively and the next target sequencing was performed to define recurrently mutated genes in these disease samples, to examine the association of the clinical and molecular signatures with response to DAC treatment. Results: Of 109 MDS and related neoplasms patients, there were 70 males and 39 females, the median age was 61 years old (ranges: 17-85 years old) . According to the international prognostic scoring system (IPSS) , 46 cases were included in the relatively low risk group (low risk and intermediate-1 risk) , 63 in the relative high risk group (intermediate-2 and high risk) . There were 21 cases with complex karyotype, 17 chromosome 7 abnormality and 17 monosomal karyotype. The median courses of DAC treatment was 4 (2-11) . A total of 74 patients achieved response (67.9%) and 30 (27.5%) achieved complete response (CR) . Univariate analysis found that CR was higher in patients with high risk of IPSS, complex karyotypes, monosomal karyotypes, chromosome 7 abnormality, and platelet doubling after one cycle of DAC treatment. Patients with TP53 gene mutation were more likely to receive CR, 10 of 15 patients with TP53 mutations achieved CR. (66.7%) , which was significantly higher than that of the patients without TP53 gene mutation (21.3%) ( P =0.001) . Multivariate analysis showed that TP53 gene mutation, platelet doubling after one cycle of DAC treatment and the complex karyotype were independent prognostic factors for CR. Of them, TP53 gene mutation is the strongest predictor ( OR =4.39, 95% CI , 1.20-16.06, P =0.026) . Conclusion: TP53 mutation, platelet doubling after one cycle of DAC treatment and complex karyotypes could predict CR to DAC.

To identify the molecular signatures that predict responses to decitabine (DAC), we examined baseline gene mutations (28 target genes) in 109 myelodysplastic syndrome (MDS) patients at diagnosis. We determined that TP53 mutations predicted complete response (CR), as 10 of 15 patients (66·7%) who possessed TP53 mutations achieved a CR. Univariate and multivariate analyses showed that TP53 mutations are the only molecular signatures predictive of a CR to DAC in MDS. Among the ten patients with TP53 mutations who achieved a CR, nine presented with complex karyotypes due to abnormalities involving chromosome 5 and/or chromosome 7, and eight possessed monosomies. Although TP53 mutations were associated with a higher frequency of CRs, they were not associated with improved survival. Poor outcomes were attributed to early relapses and transformation to acute myeloid leukaemia after CR. Post-DAC therapy patient gene mutation profiles showed that most CR patients exhibited fewer gene mutations after achieving a CR. It seems that suppression of these gene mutations was facilitated by DAC, resulting in a CR. In summary, TP53 mutations might predict decitabine-induced complete responses in patients with MDS. DAC-induced responses may result from partial suppression of malignant clones containing mutated TP53 genes., (© 2016 John Wiley & Sons Ltd.)

The role of EZH2 in cancer is complex and may vary depending on cancer type or stage. We examined the effect of altered EZH2 levels on H3K27 methylation, HOX gene expression, and malignant phenotype in myelodysplastic syndrome (MDS) cell lines and an in vivo xenograft model. We also studied links between EZH2 expression and prognosis in MDS patients. Patients with high-grade MDS exhibited lower levels of EZH2 expression than those with low-grade MDS. Low EZH2 expression was associated with high percentages of blasts, shorter survival, and increased transformation of MDS into acute myeloid leukemia (AML). MDS patients frequently had reductions in EZH2 copy number. EZH2 knockdown increased tumor growth capacity and reduced H3K27me3 levels in both MDS-derived leukemia cells and in a xenograft model. H3K27me3 levels were reduced and HOX gene cluster expression was increased in MDS patients. EZH2 knockdown also increased HOX gene cluster expression by reducing H3K27me3, and H3K27 demethylating agents increased HOX gene cluster expression in MDS-derived cell lines. These findings suggest genomic loss of EZH2 contributes to overexpression of the HOX gene clusters in MDS through epigenetic modifications.

The progressive mechanism underlying myelodysplastic syndrome remains unknown. Here we identify ROBO1 and ROBO2 as novel progression-related somatic mutations using whole-exome and targeted sequencing in 6 of 16 (37.5%) paired MDS patients with disease progression. Further deep sequencing detects 20 (10.4%) patients with ROBO mutations in a cohort of 193 MDS patients. In addition, copy number loss and loss of heterogeneity (LOH) of ROBO1 and ROBO2 are frequently observed in patients with progression or carrying ROBO mutations. In in vitro experiments, overexpression of ROBO1 or ROBO2 produces anti-proliferative and pro-apoptotic effects in leukaemia cells. However, this effect was lost in ROBO mutants and ROBO-SLIT2 signalling is impaired. Multivariate analysis shows that ROBO mutations are independent factors for predicting poor survival. These findings demonstrate a novel contribution of ROBO mutations to the pathogenesis of MDS and highlight a key role for ROBO-SLIT2 signalling in MDS disease progression.

Objective: To investigate the osteogenic differentiation potential of bone marrow mesenchymal stem cells (BMMSC) in patients with myelodysplastic syndromes (MDS) and to explore the role of BMMSC osteogenic differentiation in the pathogenesis of MDS., Methods: BMMSC were isolated from bone marrow of patients with MDS and healthy donors, then expanded in vitro. The expression of transcription factor gene RUNX2, Osterix and osteogenic differentiation markers (ALP, BSP, OPN, OCN) were measured by real-time PCR, the alkaline phosphatase(ALP) activity was assessed at 3, 7, 10 days after osteogenic differentiation. Mineralization analysis was performed at day 21 of osteogenic induction., Results: The expression level of RUNX2 and Osterix were significantly decreased in BMMSC from lower-risk MDS patients compared with normal controls (P<0.05). After osteogenic induction, low-risk MDS showed lower alkaline phosphatase activity at day 3 (P<0.05), less intense alizarin red S staining at day 21 (P<0.05), and lower gene expression of osteogenic differentiation markers (P<0.05), however, these expressions in higher-risk MDS were normal., Conclution: BMMSC from low-risk MDS have abnormalities in osteogenic differentiation, it may contribute to the ineffective hamatopoiesis of MDS.

Rigosertib has demonstrated therapeutic activity for patients with high-risk myelodysplastic syndrome (MDS) in clinical trials. However, the role of rigosertib in MDS has not been thoroughly characterized. In this study, we found out that rigosertib induced apoptosis, blocked the cell cycle at the G2/M phase and subsequently inhibited the proliferation of CD34+ cells from MDS, while it minimally affected the normal CD34+ cells. Further studies showed that rigosertib acted via the activation of the P53 signaling pathway. Bioinformatics analysis based on gene expression profile and flow cytometry analysis revealed the abnormal activation of the Akt-PI3K, Jak-STAT and Wnt pathways in high-grade MDS, while the p38 MAPK, SAPK/JNK and P53 pathways were abnormally activated in low-grade MDS. Rigosertib could markedly inhibit the activation of the Akt-PI3K and Wnt pathways, whereas it activated the SAPK/JNK and P53 pathways in high-grade MDS. A receptor tyrosine kinase phosphorylation array demonstrated that rigosertib could increase the activation of RET and PDGFR-β while reducing the activation of Tie2 and VEGFR2 in MDS cells. Taken together, these data indicate that rigosertib is a selective and promising anti-tumor agent that could ameliorate multiple dysregulated signaling transduction pathways in high-grade MDS.

This study was aimed to investigated the mRNA expression levels of Notch ligands- Delta-like-1 and Jagged-1 in bone marrow mesenchymal stem cells of patients with myelodysplastic syndrome (MDS), and to explore their relation with onset of MDS. Bone marrow mesenchymal stem cells of 38 patients with MDS and 16 normal subjects as control were collected to detect mRNA expression of Delta-like-1 and Jagged-1 by using real-time quantitative polymerase chain reaction. The results showed that the expression levels of Delta-like-1 and Jagged-1 in mesenchymal stem cells of MDS patients were significantly higher than that in normal controls (P < 0.05). According to WHO criteria, the mRNA expression of Delta-like-1 in RA/RAS, RCMD and RAEB groups were significantly higher than that in normal controls (P < 0.05), the mRNA expression of Jagged-1 in RAEB group was also significantly higher than that in normal controls (P < 0.05). The mRNA expression of Delta-like-1 was significantly correlated with the proportion of blasts in the bone marrow of MDS patients (r = 0.502, P < 0.05). The expression levels of Delta-like-1 and Jagged-1 in MDS patients with abnormal karyotypes were significantly higher than those in MDS patients with normal karyotypes (P < 0.05). The mRNA expression of Delta-like-1 in higher risk group according to International Prognostic Scoring System was significantly higher than that in lower risk group (P < 0.05), there was no significant difference in Jagged-1 expression levels between higher risk group and lower risk group (P > 0.05). It is concluded that the changes of Delta-like-1 and Jagged-1 expression level in MSC may play a role in the pathogenesis of myelodysplastic syndrome.

Objective: To study the methylation status of p73 gene promoter in patients with myelodysplastic syndrome (MDS) and explore its significance with clinical prognosis., Methods: Methylation of p73 promoter was detected in bone marrow cells from 135 MDS patients and 13 healthy controls by methylation-specific PCR (MSP). The results of MSP were confirmed by bisulfite sequencing. The expression of p73 mRNA was detected by real-time quantitative PCR. Primary bone marrow cells from MDS patients were treated with decitabine, the changes of p73 methylation status and p73 mRNA expression were measured. The role of p73 methylation in the prognosis of MDS and the correlated clinical data were explored., Results: p73 hypermethylation was present in 37.04% of MDS cases and patients with high risk MDS (RAEB-1 and RAEB-2) exhibited a significantly higher frequency of p73 methylation than that of low risk MDS (58.8% vs 29.7%, P = 0.002). The expression of p73 mRNA in the methylated group was decreased compared to that of the unmethylated group (P = 0.032). Decitabine treatment decreased the level of p73 methylation and increased the level of p73 transcripts. Patients with p73 methylation progressed rapidly to AML (P < 0.001) and had shorter survival (P = 0.002) than those who did not have p73 methylation. In the multivariate Cox regression model, BM blast and p73 methylation status emerged as independent prognostic factor for overall survival and leukemia free survival., Conclusion: p73 gene methylation is common in patients with MDS and may indicate poor prognosis. p73 may be a therapeutic target in MDS.

This study was purposed to explore the expression of p57kip2 in the bone marrow of patients with de novo myelodysplastic syndrome (MDS) and its role in MDS pathogenesis, as well as the relationship between the expression of p57kip2 and SDF-1/CXCR4 signal. The expression of p57kip2 and CXCR4 in 67 de novo MDS patients was measured by real-time quantitative PCR. The percentage of CD34(+) cells in the bone marrow from MDS patients was measured by flow cytometry. 18 healthy volunteers were recruited for control. The effect of SDF-1 on p57kip2 expression in bone marrow mononuclear cell (BMMNC) from MDS or normal controls was investigated in vitro, and difference between them was compared. The results showed that low-risk MDS and high-risk MDS displayed a significant reduction of p57kip2 mRNA expression in BMMNC compared with that in control group (P < 0.001) and there was a negative correlation between p57kip2 expression and percentage of CD34(+) (r = -0.458, P < 0.001); the patients with abnormal karyotype showed lower expression of p57kip2 gene, compared to patients with normal karyotype (P = 0.045). Although the expression of CXCR4 had no difference between MDS patients and normal controls, a positive correlation between p57kip2 and CXCR4 in MDS patients was still found (r = 0.609, P < 0.001). Moreover, SDF-1 increased p57kip2 expression in normal BMMNC in dose-dependent manner, but BMMNC from MDS patients showed no response to SDF-1. SDF-1-induced p57 expression was blocked by AMD3100. It is concluded that the low expression of p57 gene in MDS may play a role in the pathogenesis of MDS. Furthermore, SDF-1-induced p57kip2 expression in BMMNC, and the decreasing response of BMMNC to SDF-1 may contribute to the low expression of p57kip2 in MDS patients.

The purpose of this study was to evaluate the biological behavior of stromal cell-derived factor-1 (SDF-1) in migration, adhesion and apoptosis as well as the related signaling transduction pathways in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). 37 patients with MDS, 10 patients with de novo AML and 14 patients with non-clonal cytopenia diseases were chosen for this study. The expression level of CXCR4 on CD34(+) cells and apoptosis of CD34(+) cells in bone marrow were detected by flow cytometry; the chemotaxis of SDF-1 on bone marrow mononuclear cells in 4 patients with low risk MDS (IPSS score ≤ 1.0) and 5 patients with high risk MDS (IPSS score ≥ 1.5) was assayed by transwell migration test of cells. The effect of SDF-1 on cell adhesion capability was measured by using CCK-8 method. The results indicated that the apoptosis rate of CD34(+) cells was significantly higher in MDS patients with low risk (IPPS score < 1.0) than that in MDS patients with high risk (IPSS score ≥ 1.5) (21.55% vs 7.52%, p < 0.001); as well, the apoptosis rate of CD34(+) cells was significantly higher in MDS patients with low risk than that in de novo AML patients (21.55% vs 7.33%, p < 0.001), no relation of CD34(+) cell apoptosis with age and sex of patients was found. SDF-1 could promote the cells of patients with CXCR4 high expression to adhere to the stroma cells, and induce migration of these cells, as well as, SDF-1 could trigger the polarization of the cells which highly expressed CXCR4. After addition of pertussis toxin, wortmannin and AMD3100, the ability of adhersion and migration of the cells with highly expressed CXCR4 decreased, but there was no above-mentioned phenomenon in patients who lowly expressed CXCR4. It is concluded that the SDF-1/CXCR4 axis enhances the ability of cell adhesion and migration through PI3K signaling pathway, thereby plays antiapoptosis role, moreover the above-mentioned effects can be blocked by PI3K pathway inhibitor and G protein inhibitor.