An elastase nanocomplex with metal cofactors for enhancement of target protein cleavage activity and synergistic antitumor effect

Neutrophil elastase (ELANE) plays a vital role in recognizing and destroying various cancer cells by cleaving target proteins, making it a promising therapeutic option. However, in vivo therapeutic effectiveness of ELANE is limited due to its inadequate protein cleavage efficiency, lack of tumor tissue targeting, and susceptibility to serine protease inhibition. Drawing inspiration from the ways metal ions regulate protein functions and activities, a metal cofactor-based approach was employed to enhance target protein cleavage and antitumor effects, using porcine pancreatic elastase (PPE, an ELANE homolog) as a model drug in this study. In a nutshell, an elastase nanocomplex with enhanced cleavage activity (CAEN) was developed and optimized in vitro. Administered through inhalation, CAEN prevented the degradation of PPE in the biological environment and efficiently delivered it to tumor cells. By effectively cleaving the transmembrane protein CD95 with higher specificity compared to free PPE, CAEN induced significant apoptosis in lung cancer cells. Furthermore, the released metal ions could activate type I interferon in macrophages, further enhancing the local immune response within lung tumor tissues. Overall, this study presents a novel approach to substantially enhance the specificity of protein drugs in terms of drug delivery and pharmacological effects.