Laminin, as a key component of the basement membrane extracellular matrix (ECM), regulates tissue morphogenesis. Here, we show that multiple laminin isoforms promiscuously bind to growth factors (GFs) with high affinity, through their heparin-binding domains (HBDs) located in the α chain laminin-type G (LG) domains. These domains also bind to syndecan cell-surface receptors, promoting attachment of fibroblasts and endothelial cells. We explore the application of these multifunctional laminin HBDs in wound healing in the type-2 diabetic mouse. We demonstrate that covalent incorporation of laminin HBDs into fibrin matrices improves retention of GFs and significantly enhances the efficacy of vascular endothelial cell growth factor (VEGF-A165) and platelet-derived growth factor (PDGF-BB) in promoting wound healing in vivo, under conditions where the GFs alone in fibrin are inefficacious. This laminin HBD peptide may be clinically useful by improving biomaterial matrices as both GF reservoirs and cell scaffolds, leading to effective tissue regeneration.

Checkpoint inhibitor (CPI) immunotherapy has achieved remarkable clinical success, yet its efficacy in 'immunologically cold' tumours has been modest. Interleukin (IL)-12 is a powerful cytokine that activates the innate and adaptive arms of the immune system, yet its administration has been associated with immune-related adverse events. Here, we show that the intravenous administration of a collagen-binding domain fused to IL-12 (CBD-IL-12) in mice bearing aggressive murine tumours accumulates in the tumour stroma, owing to exposed collagen in the disordered tumour vasculature. In comparison with the administration of unmodified IL-12, CBD-IL-12 induced sustained intratumoral levels of interferon-, markedly reduced its systemic levels as well as organ damage, and led to superior anticancer efficacy, eliciting complete regression of CPI-unresponsive breast tumours. Furthermore, CBD-IL-12 potently synergized with CPI to eradicate large established melanoma, induced antigen-specific immunological memory, and controlled tumour growth in a genetically engineered mouse model of melanoma. CBD-IL-12 may potentiate CPI immunotherapy for immunologically cold tumours.

Immune checkpoint blockade exhibits considerable antitumor activity, but previous studies have reported instances of severe treatment-related adverse events. We sought to explore local immune checkpoint blockade, with an antibody (Ab) form that would be retained intra- or peritumorally, limiting systemic exposure. To accomplish this, we conjugated the checkpoint blockade Abs to an extracellular matrix (ECM)-super-affinity peptide derived from placenta growth factor-2 (PlGF-2). We show enhanced tissue retention and lower Ab concentrations in blood plasma after PlGF-2 conjugation, reducing systemic side effects such as the risk of autoimmune diabetes. Peritumoral injections of PlGF-2-anti-CTLA4 (cytotoxic T lymphocyte antigen 4) and PlGF-2-anti-PD-L1 (programmed death ligand 1) Abs delayed tumor growth and prolonged survival compared to the unmodified Abs in genetically engineered murine tumor models of melanoma and breast cancer. The PlGF-2-Abs increased tumor-infiltrating activated CD8 and CD4 T cells, resulting in a delay of distant tumor growth as well. This simple and translatable approach of engineered ECM-binding Abs may present a viable and safer approach in checkpoint blockade.