Stereochemical Control of Splice Modulation in FD-895 Analogues.

Highly functionalized skeletons of macrolide natural products gain access to rare spatial arrangements of atoms, where changes in stereochemistry can have a profound impact on the structure and function. Spliceosome modulators present a unique consensus motif, with the majority targeting a key interface within the SF3B spliceosome complex. Our recent preparative-scale synthetic campaign of 17S-FD-895 provided unique access to stereochemical analogues of this complex macrolide. Here, we report on the preparation and systematic activity evaluation of multiple FD-895 analogues. These studies examine the effects of modifications at specific stereocenters within the molecule and highlight future directions for medicinal chemical optimization of spliceosome modulators.

Stem Cell Microarrays for Assessing Growth Factor Signaling in Engineered Glycan Microenvironments.

Extracellular glycans, such as glycosaminoglycans (GAGs), provide an essential regulatory component during the development and maintenance of tissues. GAGs, which harbor binding sites for a range of growth factors (GFs) and other morphogens, help establish gradients of these molecules in the extracellular matrix (ECM) and promote the formation of active signaling complexes when presented at the cell surface. As such, GAGs have been pursued as biologically active components for the development of biomaterials for cell-based regenerative therapies. However, their structural complexity and compositional heterogeneity make establishing structure-function relationships for this class of glycans difficult. Here, a stem cell array platform is described, in which chemically modified heparan sulfate (HS) GAG polysaccharides are conjugated to a gelatin matrix and introduced into a polyacrylamide hydrogel network. This array allowed for direct analysis of HS contributions to the signaling via the FGF2-dependent mitogen activated protein kinase (MAPK) pathway in mouse embryonic stem cells. With the recent emergence of powerful synthetic and recombinant technologies to produce well-defined GAG structures, a platform for analyzing both growth factor binding and signaling in response to the presence of these biomolecules will provide a powerful tool for integrating glycans into biomaterials to advance their biological properties and applications.

Splice Modulation Synergizes Cell Cycle Inhibition.

While recognized as a therapeutic target, the spliceosome may offer a robust vector to improve established therapeutics against other protein targets. Here, we describe how modulating the spliceosome using small molecule splice modulators (SPLMs) can prime a cell for sensitivity to a target-specific drug. Using the cell cycle regulators aurora kinase and polo-like kinase as models, this study demonstrates how the combination of SPLM treatment in conjunction with kinase inhibition offers synergy for antitumor activity using reduced, sublethal levels of SPLM and kinase inhibitors. This concept of splice-modulated drug attenuation suggests a possible approach to enhance therapeutic agents that have shown limited applicability due to high toxicity or low efficacy.