Neural ganglioside GD2(+) cells define a subpopulation of mesenchymal stem cells in adult murine bone marrow.

BACKGROUND/AIMS: Due to the lack of specific markers, the isolation of pure mesenchymal stem cells (MSCs) from murine bone marrow remains an unsolved problem. The present study explored whether the neural ganglioside GD2 could serve as a single surface marker to uniquely distinguish murine bone marrow MSCs (mBM-MSCs) from other marrow elements. METHODS: Immunocytochemistry and flow cytometry, in combination with quantitative RT-PCR, were used to identify the expression of GD2 on culture-expanded mBM-MSCs. GD2(+) and GD2(-) fractions from mBM-MSCs cultures were sorted by immunosorting. Flow cytometry was performed to further analyze the biomarkers of GD2-sorted and unsorted cells. Employing CFU-F assay and CCK-8 assay, we examined the clonogenic and proliferative capabilities of GD2-sorted and unsorted cells. Using oil red O and von Kossa staining assay, we also assessed the multi-lineage potential of GD2-sortedand unsorted cells. RESULTS: We found that mBM-MSCs expressed a novel surface marker the neural ganglioside GD2. Importantly, mBM-MSCs were the only cells within bone marrow that expressed this marker. Further studies demonstrated that a homogenous population of MSCs could be obtained from bone marrow cultures in early passages by GD2 immunosorting. Compared to parental cells, GD2(+)-sorted cells not only possessed much higher clonogenic and proliferative capabilities but also had significantly stronger differentiation potential to adipocytes and osteoblasts. Furthermore, GD2(+)-sorted cells displayed enhanced expression of ES markers SSEA-1 and Nanog. CONCLUSION: Our observations provide the first demonstration that GD2 may serve as a maker for identification and purification of mBM-MSCs. Meanwhile, our study indicates that the cells selected by GD2 are a subpopulation of MSCs with features of primitive precursor cells.

Prediction of competing endogenous RNA coexpression network as prognostic markers in AML.

Recently, competing endogenous RNAs (ceRNAs) hypothesis has gained a great interest in the study of molecular biological mechanisms of cancer occurrence and progression. However, studies on leukemia are limited, and there is still a lack of comprehensive analysis of lncRNA-miRNA-mRNA ceRNA regulatory network of AML based on high-throughput sequencing and large-scale sample size. We obtained RNA-Seq data and compared the expression profiles between 407 normal whole blood (GTEx) and 151 bone marrows of AML (TCGA). The similarity between two sets of genes with trait in the network was analyzed by weighted correlation network analysis (WGCNA). MiRcode, starBase, miRTarBase, miRDB and TargetScan was used to predict interactions between lncRNAs, miRNAs and target mRNAs. At last, we identified 108 lncRNAs, 10 miRNAs and 8 mRNAs to construct a lncRNA-miRNA-mRNA ceRNA network, which might act as prognostic biomarkers of AML. Among the network, a survival model with 8 target mRNAs (HOXA9+INSR+KRIT1+MYB+SPRY2+UBE2V1+WEE1+ZNF711) was set up by univariate and multivariate cox proportional hazard regression analysis, of which the AUC was 0.831, indicating its sensitivity and specificity in AML prognostic prediction. CeRNA networks could provide further insight into the study on gene regulation and AML prognosis.

Aurora A Kinase Inhibitor AKI603 Induces Cellular Senescence in Chronic Myeloid Leukemia Cells Harboring T315I Mutation.

The emergence of resistance to imatinib mediated by mutations in the BCR-ABL has become a major challenge in the treatment of chronic myeloid leukemia (CML). Alternative therapeutic strategies to override imatinib-resistant CML are urgently needed. In this study, we investigated the effect of AKI603, a novel small molecule inhibitor of Aurora kinase A (AurA) to overcome resistance mediated by BCR-ABL-T315I mutation. Our results showed that AKI603 exhibited strong anti-proliferative activity in leukemic cells. AKI603 inhibited cell proliferation and colony formation capacities in imatinib-resistant CML cells by inducing cell cycle arrest with polyploidy accumulation. Surprisingly, inhibition of AurA by AKI603 induced leukemia cell senescence in both BCR-ABL wild type and T315I mutation cells. Furthermore, the induction of senescence was associated with enhancing reactive oxygen species (ROS) level. Moreover, the anti-tumor effect of AKI603 was proved in the BALB/c nude mice KBM5-T315I xenograft model. Taken together, our data demonstrate that the small molecule AurA inhibitor AKI603 may be used to overcome drug resistance induced by BCR-ABL-T315I mutation in CML.

A novel compound against oncogenic Aurora kinase A overcomes imatinib resistance in chronic myeloid leukemia cells.

Drug resistance still represents a major obstacle to successful chronic myeloid leukemia (CML) treatment and novel compounds or strategies to override this challenging problem are urgently required. Here, we evaluated a novel compound AKI603 against oncogenic Aurora kinase A (Aur-A) in imatinib-resistant CML cells. We found that Aur-A was highly activated in imatinib-resistant KBM5-T315I cells. AKI603 significantly inhibited the phosphorylation of Aur-A kinase at Thr288, while had little inhibitory effect on BCR-ABL kinase in both KBM5 and KBM5-T315I cells. AKI603 inhibited cell viability, and induced cell cycle arrest with polyploidy accumulation in KBM5 and KBM5-T315I cells. Moreover, inhibition of Aur-A kinase by AKI603 suppressed colony formation capacity without promoting obvious apoptosis. Importantly, AKI603 promoted cell differentiation in both CML cell types. Thus, our study suggested the potential clinical use of small molecule Aurora kinase inhibitor AKI603 to overcome imatinib resistance in CML treatment.