Inhibition of Eph/ephrin interaction with the small molecule UniPR500 improves glucose tolerance in healthy and insulin-resistant mice.

Eph/ephrin interactions and their bidirectional signaling are integral part of the complex communication system between ß-cells, essential for glucose homeostasis. Indeed, Eph/ephrin system was shown to be directly involved in the glucose-stimulated insulin secretion (GSIS) process occurring in the pancreatic islets. Here we tested the Eph antagonist UniPR500 as GSIS enhancer. UniPR500 was validated as EphA5-ephrin-A5 inhibitor in vitro and its efficacy as GSIS enhancer was assessed on EndoC-ßH1 cells. The selectivity of UniPR500 was evaluated by testing this compound on a panel of well-known molecular targets responsible for the regulation of glucose homeostasis. Plasmatic levels of UniPR500 were measured by HPLC/MS approach after oral administration. Finally, UniPR500 was tested as hypoglycemic agent in healthy mice, in a non-genetic mouse model of insulin resistance (IR) and in a non-genetic mouse model of type 1 diabetes (T1D). The compound is an orally bioavailable and selective Eph antagonist, able to increase GSIS from EndoC-ßH1 cells. When tested in vivo UniPR500 showed to improve glucose tolerance in healthy and IR mice. As expected by a GSIS enhancer acting on healthy ß-cells, UniPR500 was ineffective when tested on a non-genetic mouse model of type 1 diabetes, where pancreatic function was severely compromised. In conclusion our findings suggest that Eph targeting is a new and valuable pharmacological strategy in the search of new hypoglycemic agents.

Patient similarity by joint matrix trifactorization to identify subgroups in acute myeloid leukemia.

OBJECTIVE: Computing patients' similarity is of great interest in precision oncology since it supports clustering and subgroup identification, eventually leading to tailored therapies. The availability of large amounts of biomedical data, characterized by large feature sets and sparse content, motivates the development of new methods to compute patient similarities able to fuse heterogeneous data sources with the available knowledge. MATERIALS AND METHODS: In this work, we developed a data integration approach based on matrix trifactorization to compute patient similarities by integrating several sources of data and knowledge. We assess the accuracy of the proposed method: (1) on several synthetic data sets which similarity structures are affected by increasing levels of noise and data sparsity, and (2) on a real data set coming from an acute myeloid leukemia (AML) study. The results obtained are finally compared with the ones of traditional similarity calculation methods. RESULTS: In the analysis of the synthetic data set, where the ground truth is known, we measured the capability of reconstructing the correct clusters, while in the AML study we evaluated the Kaplan-Meier curves obtained with the different clusters and measured their statistical difference by means of the log-rank test. In presence of noise and sparse data, our data integration method outperform other techniques, both in the synthetic and in the AML data. DISCUSSION: In case of multiple heterogeneous data sources, a matrix trifactorization technique can successfully fuse all the information in a joint model. We demonstrated how this approach can be efficiently applied to discover meaningful patient similarities and therefore may be considered a reliable data driven strategy for the definition of new research hypothesis for precision oncology. CONCLUSION: The better performance of the proposed approach presents an advantage over previous methods to provide accurate patient similarities supporting precision medicine.

UniPR129 is a competitive small molecule Eph-ephrin antagonist blocking in vitro angiogenesis at low micromolar concentrations.

BACKGROUND AND PURPOSE: The Eph receptor tyrosine kinases and their ephrin ligands are key players in tumorigenesis and many reports have correlated changes in their expression with a poor clinical prognosis in many solid tumours. Agents targeting the Eph-ephrin system might emerge as new tools useful for the inhibition of different components of cancer progression. Even if different classes of small molecules targeting Eph-ephrin interactions have been reported, their use is hampered by poor chemical stability and low potency. Stable and potent ligands are crucial to achieve robust pharmacological performance. EXPERIMENTAL APPROACH: UniPR129 (the L-homo-Trp conjugate of lithocholic acid) was designed by means of computational methods, synthetized and tested for its ability to inhibit the interaction between the EphA2 receptor and the ephrin-A1 ligand in an elisa binding study. The ability of UniPR129 to disrupt EphA2-ephrin-A1 interaction was functionally evaluated in a prostate adenocarcinoma cell line and its anti-angiogenic effect was tested in vitro using cultures of HUVECs. KEY RESULTS: UniPR129 disrupted EphA2-ephrin-A1 interaction with Ki = 370 nM in an elisa binding assay and with low micromolar potency in cellular functional assays, including inhibition of EphA2 activation, inhibition of PC3 cell rounding and disruption of in vitro angiogenesis, without cytotoxic effects. CONCLUSIONS AND IMPLICATIONS: The discovery of UniPR129 represents not only a major advance in potency compared with the existing Eph-ephrin antagonists but also an improvement in terms of cytotoxicity, making this molecule a useful pharmacological tool and a promising lead compound.

Rac1 signaling regulates CTGF/CCN2 gene expression via TGFbeta/Smad signaling in chondrocytes.

OBJECTIVE: Connective tissue growth factor (CTGF) has been implicated in regulation of chondrocyte differentiation at multiple steps and has been implicated in the progression of diseases such as scleroderma and osteoarthritis. However, the pathways mediating the expression of CTGF/CCN2 and related factors in cartilage are not fully understood. We have previously shown that the Rho family of proteins and the actin cytoskeleton regulate both early and late chondrocyte differentiation. RESULTS: Here we demonstrate that several CTGF/Cyr61/Nov (CCN) family members are differentially affected by either inhibition of actin polymerization (cytochalasin D treatment), promotion of actin polymerization (jasplakinolide treatment), inhibition of RhoA/rho kinase (ROCK) signaling (Y27632 treatment) and Rac1 signaling. We also show that the Smad site in the CTGF/CCN2 promoter is responsive to both Rac1 inhibition and cytochalasin D treatment, suggesting a role of TGFbeta/Smad signaling in mediating the effects of actin dynamics and Rac1. CONCLUSION: Collectively, these data show that Rac1 and actin pathways control CTGF/CCN2 expression in chondrocytes which might be relevant to both skeletal development and associated diseases such as osteoarthritis.