Cotargeting the JAK/STAT signaling pathway and histone deacetylase by ruxolitinib and vorinostat elicits synergistic effects against myeloproliferative neoplasms.

The majority of patients with Philadelphia-negative myeloproliferative neoplasms (MPNs) harbor a gain of function mutation V617F in Janus kinase (JAK) 2. Although JAK2 inhibitors such as ruxolitinib have been shown to be clinically efficacious, the hematological toxicity and eventual drug resistance limit its use as monotherapy. Other gene mutations or dysregulation correlated with the disease phenotype and prognosis have been found to contribute to the complexity and heterogeneity of MPNs, giving rise to an increasing demand for combination therapies. Here, we combine ruxolitinib and the histone deacetylase inhibitor vorinostat as a rational combination strategy for MPNs. We tested the combination of ruxolitinib and vorinostat in cells with the JAK2V617F mutation, such as HEL cells, c-Kit+ cells from JAK2V617F transgenic mice and bone marrow mononuclear cells (BMMNCs) from patients with MPN. Our results showed significant synergistic effects of this combination strategy. Cotreatment with ruxolitinib and vorinostat synergistically induced apoptosis, cell cycle arrest and inhibition of the colony-forming capacity of HEL cells by attenuating the JAK/signal transducer and activator of transcription (STAT) and protein kinase-B (AKT) signaling pathways. In particular, cotreatment with ruxolitinib and vorinostat prevented the formation of large colonies of colony-forming unit-granulocyte/erythroid/macrophage/megakaryocytes (CFU-GEMMs) and colony-forming unit-granulocyte/macrophages (CFU-GMs) derived from the BMMNCs of patients with MPN. Taken together, these data provided preclinical evidence that the combination of ruxolitinib and vorinostat is a potential dual-target therapy for patients with MPN.

[Bioinformatics Analysis of Core Genes and Key Pathways in Myelodysplastic Syndrome].

OBJECTIVE: To screen differentially expressed gene (DEG) related to myelodysplastic syndrome (MDS) based on Gene Expression Omnibus (GEO) database, and explore the core genes and pathogenesis of MDS by analyzing the biological functions and related signaling pathways of DEG. METHODS: The expression profiles of GSE4619, GSE19429, GSE58831 including MDS patients and normal controls were downloaded from GEO database. The gene expression analysis tool (GEO2R) of GEO database was used to screen DEG according to | log FC (fold change) |≥1 and P<0.01. David online database was used to annotate gene ontology function (GO). Metascape online database was used to enrich and analyze differential genes in Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein-protein interaction network (PPI) was constructed by using STRING database. CytoHubba and Mcode plug-ins of Cytoscape were used to analyze the key gene clusters and hub genes. R language was used to diagnose hub genes and draw the ROC curve. GSEA enrichment analysis was performed on GSE19429 according to the expression of LEF1. RESULTS: A total of 74 co-DEG were identified, including 14 up-regulated genes and 60 down regulated genes. GO enrichment analysis indicated that BP of down regulated genes was mainly enriched in the transcription and regulation of RNA polymerase II promoter, negative regulation of cell proliferation, and immune response. CC of down regulated genes was mainly enriched in the nucleus, transcription factor complexes, and adhesion spots. MF was mainly enriched in protein binding, DNA binding, and ß-catenin binding. KEGG pathway was enriched in primary immunodeficiency, Hippo signaling pathway, cAMP signaling pathway, transcriptional mis-regulation in cancer and hematopoietic cell lineage. BP of up-regulated genes was mainly enriched in type I interferon signaling pathway and viral response. CC was mainly enriched in cytoplasm. MF was mainly enriched in RNA binding. Ten hub genes and three important gene clusters were screened by STRING database and Cytoscape software. The functions of the three key gene clusters were closely related to immune regulation. ROC analysis showed that the hub genes had a good diagnostic significance for MDS. GSEA analysis indicated that LEF1 may affect the normal function of hematopoietic stem cells by regulating inflammatory reaction, which further revealed the pathogenesis of MDS. CONCLUSION: Bioinformatics can effectively screen the core genes and key signaling pathways of MDS, which provides a new strategy for the diagnosis and treatment of MDS.

Thrombosis among 1537 patients with JAK2V617F -mutated myeloproliferative neoplasms: Risk factors and development of a predictive model.

To explore the risk factors of thrombosis in patients with JAK2V617F -mutated myeloproliferative neoplasms (MPNs), a cohort of 1537 Chinese patients with JAK2V617F -mutated MPN was retrospectively analyzed. The Kaplan-Meier method and multivariate Cox analysis were used to study the risk factors of thrombosis in patients with JAK2V617F -mutated MPN. Among the 1537 MPN patients, 931, 468, and 138 had polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), respectively. The median follow-up time was 7 years (range 1-47), and 12.8% of patients (197/1537) died during this period. A total of 16.8% (259/1399) of PV and ET patients had secondary myelofibrosis, and 2.5% (38/1537) of patients developed acute myeloid leukemia (AML). Thrombotic events occurred in 43.9% (675/1537) of patients, among which 91.4% (617/675) were arterial thrombosis and 16.6% (112/675) were venous thrombosis. The number of thrombotic events in PV, ET, and PMF patients was 439 (47.2%), 197 (42.1%) and 39 (28.2%), respectively. The multivariate analysis indicated that age ≥60 years old, HCT ≥48%, at least one cardiovascular risk factor, a history of thrombosis, and JAK2V617F allele burden (V617F%) ≥50% are risk factors for thrombosis in JAK2V617F -mutated MPN. According to the results of the multivariate analysis, a risk model of thrombosis was established and comprised low-risk (0 points), intermediate-risk (1 points) and high-risk (≥2 points) groups, among which the incidence of thrombosis was 9.1%, 33.7% and 72.9%. For elderly patients with JAK2V617F -mutated MPN and a history of thrombosis, reducing the V617F%, controlling HCT and preventing cardiovascular risk factors are necessary measures to prevent thrombosis.

Alteration in the Cytokine Secretion of Bone Marrow Stromal Cells from Patients with Chronic Myelomonocytic Leukemia Contribute to Impaired Hematopoietic Supportive Activity.

Bone marrow stromal cells (BMSCs) represent an important cellular component of the bone marrow microenvironment, which play an important role in supporting and regulating the proliferation and differentiation of hematopoietic stem/progenitor cells (HSPCs). We have previously reported that the ability of BMSCs derived from CMML patients (CMML-BMSCs) in supporting the expansion of cord blood (CB) CD34+ cells was significantly reduced compared to BMSCs derived from healthy donors (HD-BMSCs). In addition, CMML-BMSCs led to a skewed differentiation of CB CD34+ cells favoring myeloid lineage compared with HD-BMSCs. To assess whether the altered cytokine secretion was one of the mechanisms to mediate the impaired hematopoietic supportive activity of CMML-BMSCs, a transwell coculture followed by cytokine array was performed. We showed that noncontacted coculture with CMML-BMSCs preferentially promoted the differentiation of CB CD34+ cells toward myeloid lineage. The expression levels of multiple cytokines (IL-6, IL-8, and GRO-ß) were markedly reduced in CMML-BMSCs compared with HD-BMSCs. By supplementing IL-6, IL-8, or GRO-ß, the hematopoietic supportive activity of CMML-BMSCs was partially restored. These results suggested that BMSCs may contribute to the pathogenesis of CMML by altering their cytokine secretion, which will shed light on the further investigation to develop novel therapeutic strategies for CMML patients.