Targeting tumour-associated macrophages in hodgkin lymphoma using engineered extracellular matrix-mimicking cryogels

Tumour-associated macrophages are linked with poor prognosis and resistance to therapy in Hodgkin lymphoma; however, there are no suitable preclinical models to identify macrophage-targeting therapeutics. We used primary human tumours to guide the development of a mimetic cryogel, wherein Hodgkin (but not Non-Hodgkin) lymphoma cells promoted primary human macrophage invasion. In an invasion inhibitor screen, we identified five drug hits that significantly reduced tumour-associated macrophage invasion: marimastat, batimastat, AS1517499, ruxolitinib, and PD-169316. Importantly, ruxolitinib has demonstrated recent success in Hodgkin lymphoma clinical trials. Both ruxolitinib and PD-169316 (a p38 mitogen-activated protein kinase (p38 MAPK) inhibitor) decreased the percent of M2-like macrophages; however, only PD-169316 enhanced the percentage of M1-like macrophages. We validated p38 MAPK as an anti-invasion drug target with five additional drugs using a high-content imaging platform. With our biomimetic cryogel, we modeled macrophage invasion in Hodgkin lymphoma and then used it for target discovery and drug screening, ultimately identifying potential future therapeutics.

Identification of RSV Fusion Protein Interaction Domains on the Virus Receptor, Nucleolin

Nucleolin is an essential cellular receptor to human respiratory syncytial virus (RSV). Pharmacological targeting of the nucleolin RNA binding domain RBD1,2 can inhibit RSV infections in vitro and in vivo; however, the site(s) on RBD1,2 which interact with RSV are not known. We undertook a series of experiments designed to: document RSV-nucleolin co-localization on the surface of polarized MDCK cells using immunogold electron microscopy, to identify domains on nucleolin that physically interact with RSV using biochemical methods and determine their biological effects on RSV infection in vitro, and to carry out structural analysis toward informing future RSV drug development. Results of immunogold transmission and scanning electron microscopy showed RSV-nucleolin co-localization on the cell surface, as would be expected for a viral receptor. RSV, through its fusion protein (RSV-F), physically interacts with RBD1,2 and these interactions can be competitively inhibited by treatment with Palivizumab or recombinant RBD1,2. Treatment with synthetic peptides derived from two 12-mer domains of RBD1,2 inhibited RSV infection in vitro, with structural analysis suggesting these domains are potentially feasible for targeting in drug development. In conclusion, the identification and characterization of domains of nucleolin that interact with RSV provide the essential groundwork toward informing design of novel nucleolin-targeting compounds in RSV drug development.