Homeobox-Pre-B-cell leukemia transcription factor protein-protein interaction (HOX-PBX PPI)

The Homeobox (HOX)-Pre-B-cell leukemia homeobox (PBX) protein-protein interaction is a critical regulatory mechanism for transcription factors involved in embryonic development and hematopoiesis (Morgan et al., 2007). HOX proteins, specifically those from paralog groups 1 through 10, utilize a highly conserved hexapeptide motif to bind to the PBX cofactor, which significantly enhances their DNA-binding affinity and specificity for target genes (Piper et al., 1999). In many adult malignancies, including acute myeloid leukemia, breast cancer, and melanoma, HOX genes are pathologically overexpressed, driving oncogenic programs that promote cell survival and inhibit apoptosis (Grier et al., 2005). Because the HOX-PBX interaction is essential for the transcriptional activity of these oncogenic HOX proteins, it has emerged as a viable therapeutic target for drug development. Therapeutic strategies, such as the peptide mimic HXR9 or small-molecule inhibitors like HTL-001, disrupt this interaction to induce programmed cell death specifically in cancer cells that are 'addicted' to HOX activity while sparing most normal adult tissues (Morgan et al., 2014; Surrey Cancer Research Institute).

Other names

HOX-PBX complexHOX-PBX interactionHomeobox-PBX1 interactionHOX-PBX dimer

Competitive inhibition of the protein-protein interaction between HOX transcription factors and their PBX cofactors by mimicking the conserved HOX hexapeptide motif, thereby preventing the formation of functional transcription complexes and inducing apoptosis in HOX-dependent malignant cells (Morgan et al., 2007; Morgan et al., 2014).