JEWJITSU PEPTIDES Research Roundup: Kv1.5 blocker, CAR‑T hydrogel, and personalized pancreatic vaccines

This report describes a de novo designer peptide called chimera toxin (CmTx) that the authors isolated by cell‑based phage‑display panning of engineered peptides on a SAK1 scaffold. The Kv1.5 channel normally repels basic pore‑blocking toxins via four arginines (R487), and the abstract states CmTx preferentially binds the slow‑inactivated Kv1.5 conformation (Ki = 127 nM) that can be promoted by rapid firing and acidosis. CmTx showed minimal inhibition of seven other Kv subtypes and scanning mutagenesis identified peptide and channel residues important for binding. AlphaFold modeling presented in the paper suggests acidic residues in CmTx can neutralize the channel arginines and permit a single peptide to plug the pore. The authors frame CmTx as both a mechanistic probe of Kv1.5 physiology and a potential lead; the mechanistic picture relies on mutagenesis and modeling and therefore will benefit from further structural and functional validation.

The second paper reports a supramolecular immunomodulatory hydrogelator developed to deliver CAR‑T cells locally together with two immunomodulatory agents, NLG919 (an IDO‑1 inhibitor) and DPPA‑1 (a PD‑L1 antagonistic peptide). According to the abstract, the material forms an in situ scaffold that functions as a sustained‑release reservoir enabling continuous co‑delivery of cells and small‑molecule/peptide agents. In murine models of aggressive melanoma, metastatic breast cancer, and postoperative glioma, a single local administration reportedly enhanced CAR‑T infiltration and persistence, stimulated endogenous tumor‑specific immune responses and durable immunological memory, and produced significant suppression of tumor growth, rechallenge, metastasis and recurrence. The authors describe the system as a versatile, potentially clinically translatable platform; as reported, these results are preclinical and model‑dependent, and additional work will be needed to assess translatability and safety beyond the presented models.

The third abstract summarizes two phase‑1 clinical trials testing personalized cancer vaccines (synthetic long peptide and DNA formats) in pancreatic ductal adenocarcinoma (NCT03956056 and NCT03122106). Vaccines were administered after resection and adjuvant chemotherapy, and tumor/normal whole‑exome sequencing, RNA sequencing and pVACtools were used to prioritize candidate neoantigens. The trials are reported as well tolerated without any grade ≥3 adverse events, and neoantigen‑specific responses were demonstrated by interferon‑γ ELISpot and intracellular cytokine staining. Expanded T cell receptor clonotypes were sequenced and transduced into autologous peripheral blood mononuclear cells to confirm neoantigen specificity. When compared with a contemporaneous propensity‑matched institutional cohort the authors report a trend toward longer median overall survival (4.4 versus 3.5 years, log‑rank P = 0.23). The abstract concludes that personalized vaccines are feasible and immunogenic in this setting; as phase‑1 studies, they are primarily focused on safety and immunogenicity and further studies are needed to establish clinical benefit.