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Holak, T. A.

Publications and source records attributed to Holak, T. A..

2 recordsLinked to original sources

IGF2 Peptide-Based LYTACs for Targeted Degradation of Extracellular and Transmembrane Proteins

Lysosome Targeting Chimeras (LYTACs) have recently been developed to facilitate lysosomal degradation of specific extracellular and transmembrane molecular targets. However, the LYTAC particles described to date are based on glycopeptide conjugates, which are difficult to prepare and produce on a large scale. Here we report the development of pure protein LYTACs based on the non-glycosylated IGF2 peptides, which can be readily produced in virtually any facility capable of monoclonal antibody production. These chimeras utilize the IGF2R/CI-M6PR pathway for lysosomal shuttling and, in our illustrative example, target programmed death ligand 1 (PD-L1), eliciting physiological effects analogous to immune checkpoint blockade. Results from in vitro assays significantly exceed the effects of anti-PD-L1 antibodies alone.

molecular biology↗

CA-170 a potent small-molecule PD-L1 inhibitor or not?

CA-170 is currently the only small-molecule modulator in clinical trials targeting PD-L1 and VISTA proteins - important negative checkpoint regulators of immune activation. The reported therapeutic results to some extent mimic those of FDA-approved monoclonal antibodies overcoming the limitations of the high production costs and adverse effects of the latter. However, no conclusive biophysical evidence proving the binding to hPD-L1 has ever been presented. Using well-known in vitro methods: NMR binding assay, HTRF and cell-based activation assays, we clearly show that there is no direct binding between CA-170 and PD-L1. To strengthen our reasoning, we performed control experiments on AUNP-12 - a 29-mer peptide, which is a precursor of CA-170. Positive controls consisted of the well-documented small-molecule PD-L1 inhibitors: BMS-1166 and peptide p57.

cancer biology↗