Antizyme inhibitor 1 (AZIN1)

Antizyme inhibitor 1 (AZIN1) is a key regulatory protein responsible for maintaining polyamine homeostasis through competitive binding of antizyme proteins, thereby permitting ornithine decarboxylase (ODC) activity and polyamine synthesis. Unlike ODC, AZIN1 lacks decarboxylase activity, but its high structural similarity allows it to tightly bind to antizymes, freeing ODC from inhibition. This regulation supports cell growth, proliferation, and oncogenic potential, as AZIN1 levels rise in diverse cancers, directly contributing to malignant transformation and poor prognosis. AZIN1 function is also modulated by RNA editing (adenosine-to-inosine), which yields functionally altered protein forms that drive tumor progression by altering cellular localization and promoting pro-oncogenic effects (e.g., upregulation of angiogenic factors such as interleukin-8). Gene knockout studies in mice demonstrate that AZIN1 is indispensable for viability, highlighting its systemic importance in both normal and pathological settings. There are no known marketed drugs with direct action on AZIN1, but it remains a potential drug target and biomarker in oncology due to its essential and pro-tumorigenic functions.

Other names

OAZINAZIA1OAZIODC1L

Drugs targeting this molecule would, in theory, modulate polyamine levels by interfering with its ability to sequester antizyme, thus reducing ornithine decarboxylase activity and polyamine synthesis