Despite the considerable success of clinically approved immune-based therapies for treating advanced melanoma, a significant fraction of patients are not responsive owing to mechanisms engaged by the tumour to evade the immune system. Here we report the surprising finding that a clinically validated and tunable self-therapeutic ultrasmall silica nanoparticle prolongs survival in a highly resistant melanoma model in combination with interleukin-6 and PD-L1 inhibition through activation of the stimulator of interferon genes/interleukin-6/PD-L1 axis and reprogramming of the tumour microenvironment towards a pro-inflammatory phenotype. In a murine model, induction of significant cytotoxic and antitumour inflammatory responses leads to differential activation of immune cell populations in a CD8-dependent manner via type I/II interferon pathways after systemic particle injection. Importantly, these immunostimulatory responses accompany significant reductions in cell populations and receptors driving suppressive activities. Mechanistic insights highlight the potential clinical utility of this platform to maximize antitumour immunity and efficacy by subverting suppressive components in the tumour microenvironment.
Osteoarthritis (OA) affects a large population worldwide, causing chronic pain, functional decline, and increased personal and societal medical costs. A major challenge in developing disease-modifying OA drugs (DMOADs) is the inefficient delivery to diseased chondrocytes. Here we synthesize a viral glycoprotein-mimicking peptide (CMP) containing a type II collagen-adhesive motif and a matrix metalloproteinase-13-activated cell-penetrating peptide sequence. The CMP peptide was conjugated to small-sized micelles loaded with the model drug IOX4, enabling the micelles to adhere to cartilage and chondrocyte surfaces through collagen binding and achieve proteinase-induced selective uptake by diseased chondrocytes. In an OA mouse model, our micelles demonstrated prolonged joint retention and exhibited a higher uptake by diseased chondrocytes compared with unmodified micelles and normal chondrocytes, respectively. In both OA mice and a clinically relevant OA sheep model, our system maintained metabolic homeostasis in cartilage, attenuating OA pathological changes and improving symptoms without causing additional toxicity. These findings suggest that our nanoformulation is a promising DMOAD candidate and provides an efficient delivery strategy for other potential DMOADs targeting intracellular sites of diseased chondrocytes.

