Researchers led by Wenshe Ray Liu at Texas A&M University described in Nature Communications on Saturday, October 3, 2026 a method called PReP-Bicyc that closes phage-displayed peptides into two rings with a designed linker, which reacts first with a cysteine at the peptide's start and then with two internal cysteines, under mild conditions that keep the phages viable. Screening a library made this way against the immune checkpoint protein PD-1 produced bicyclic peptides with binding affinities below 1 micromolar (best about 400 nM) that selectively labeled PD-1-expressing cells and blocked the PD-1/PD-L1 interaction. The reported results come from laboratory experiments.
Nature published in late August 2026 a research paper (Membranolytic peptide programs immunogenic cell death for cancer therapy, DOI 10.1038/s41586-026-10899-5) characterizing aMPC16-CA50, a pH-responsive membranolytic peptide that induces immunogenic membranolytic cell death (ICD) in tumor cells and, when combined with immune checkpoint blockade therapy (PD-1/PD-L1 inhibitors), strongly potentiates antitumor immune response in preclinical tumor models. The peptide is engineered for selective activity in the acidic microenvironment of solid tumors, sparing normal tissue at physiological pH, and its cell-death mechanism releases damage-associated molecular patterns (DAMPs) that prime dendritic cell antigen presentation and cross-priming of tumor-antigen-specific CD8+ T cells. The work adds a new mechanism to the growing membranolytic peptide anti-cancer literature that includes host-defense-peptide-derived candidates (LL-37, defensins), venom-derived amphipathic peptides (melittin analogs), and synthetic amphiphile designs. Clinical translation remains preclinical.