AGX51

AGX51 (CAS No.: 330834-54-3) is a first-in-class small-molecule chemical probe that acts as an antagonist and degrader of the pan-ID (inhibitor of DNA binding/differentiation) family (ID1–ID4). It is used in research fields such as tumor biology and angiogenesis, and represents an example of a protein–protein interaction modulator targeting the basic helix–loop–helix (bHLH) transcriptional regulatory network; it was derived from structure-guided design and high-throughput screening of the Id1–E47 interface, and validated by biophysical and biochemical methods. Mechanistically, AGX51 disrupts the ID1–E47 interaction to release E protein-driven transcriptional activity, while also promoting the downregulation of ID proteins via the ubiquitin–proteasome pathway, thereby inhibiting ID-dependent transcriptional programs; in cellular systems, perturbation of this transcriptional network is associated with cell-cycle arrest, reduced viability, and context-dependent cell death, and has been observed in multiple tumor-derived models (including triple-negative breast cancer cell lines, etc.). In terms of in vitro activity, effects based on readouts such as cell proliferation or growth inhibition are typically in the low to mid micromolar range, with specific performance influenced by factors such as cell lineage, exposure duration, and assay method. Typical research uses include: perturbing and dissecting ID-dependent transcriptional networks, evaluating the functional dependence of tumor cells on the ID pathway, exploring the molecular mechanisms of angiogenesis and ocular neovascularization, and serving as a lead compound and tool molecule in cellular and animal models or in vitro biochemical platforms for mechanism validation and screening optimization of protein–protein interaction inhibitors; the treatment concentrations or doses used in experiments typically depend on the specific experimental design and research objectives.