4-2 VHL-Recruiting PROTAC Inhibits the Growth and Migration of Triple Negative Breast Cancer Cells by Triggering Pyroptosis Through Fas-Mediated IL-17 Signaling.

SND1 is an oncoprotein found to be overexpressed in breast cancer, especially in triple-negative breast cancer(TNBC). In our previous study, a novel SND1-interacting peptide 4-2 was identified, exhibiting cytotoxicity to TNBC cells by inducing SND1 degradation. This study for the first time demonstrated the degradation of SND1 was proteasome-dependent. A series of peptide 4-2 derivatives were constructed using PROTAC technology. Among these, 4-2 VHL-recruiting PROTAC showed significantly increased SND1 degradation efficiency and higher anticancer activity to TNBC cells. The in vivo efficacy study suggested the D-isoform of 4-2VHL PROTAC suppressed the growth of TNBC cells in xenograft mouse model more effectively than peptide 4-2. Mechanistically, 4-2 VHL-recruiting PROTAC was demonstrated to induce pyroptosis of TNBC cells through Fas-mediated IL-17signaling. This study provides a new lead compound for the development of theSND1-targeted therapy via the proteolysis-targeting system.