IRAK degrader-1

Zomiradomide is a small molecule protein degrader of interleukin-1 receptor-associated kinase 4 (IRAK4) and the immunomodulatory imide drug (IMiD) substrates Ikaros (IKZF1) and Aiolos (IKZF3), with potential immunomodulating and antineoplastic activities. Upon administration, zomiradomide modulates the E3 (ubiquitin) ligase and targets IRAK4, Ikaros and Aiolos for ubiquitination. This induces proteasome-mediated degradation of IRAK4, Ikaros and Aiolos. The degradation of IRAK4 inhibits IRAK4-mediated signaling and prevents the activation of IRAK4-mediated nuclear factor-kappa B (NF-kB) signaling and decreases the expression of inflammatory cytokines and certain pro-survival factors. This inhibits the proliferation of IRAK4-overactivated tumor cells, which are found in cells harboring MYD88 activating mutations or those with overactivated toll-like receptor (TLR) pathways. The degradation of the transcription factors Ikaros and Aiolos leads to a downregulation of other proteins, including interferon regulatory factor 4 (IRF4), which upregulates type I interferon signaling and further inhibits NF-kB activation. This leads to apoptosis and the inhibition of tumor cell proliferation. IRAK4, a serine/threonine-protein kinase that plays a key role in both the TLR and IL-1R signaling pathways, is activated though the adaptor protein MYD88 and links the TLR and IL-1R signaling pathway to the NF-kB pathway.