ETO-2 inhibitors encompass a diverse group of chemicals that indirectly influence the function of ETO-2 (CBFA2T3), primarily through epigenetic modulation and transcriptional regulation. ETO-2 plays a pivotal role in hematopoietic development, functioning as a transcriptional co-repressor. This protein does not possess enzymatic activity, making direct inhibition challenging. Instead, the focus is on agents that modulate the transcriptional landscape within which ETO-2 operates. The majority of these inhibitors, such as Lenalidomide, Pomalidomide, Decitabine, Azacitidine, and various HDAC inhibitors (Vorinostat, Panobinostat, Romidepsin, Entinostat, Givinostat), function by altering the epigenetic marks or the acetylation status of histones and other proteins. These changes can significantly impact the transcriptional repression activities of ETO-2. For instance, HDAC inhibitors target histone deacetylases, enzymes that remove acetyl groups from histone proteins, leading to a more relaxed chromatin structure and increased transcriptional activity. By modulating the chromatin landscape, these inhibitors can indirectly influence the regulatory roles of ETO-2 in gene expression related to hematopoietic differentiation and proliferation.
Furthermore, compounds like JQ1, I-BET151, and OTX015, classified as BET bromodomain inhibitors, offer another mechanism for influencing ETO-2 activity. These inhibitors disrupt the interaction between BET proteins and acetylated histones, thereby altering the expression of genes under the regulatory purview of ETO-2. BET inhibitors are particularly relevant in the context of hematological malignancies, where transcriptional dysregulation plays a significant role. By perturbing the normal function of bromodomain-containing proteins, these inhibitors can modulate the transcriptional networks involving ETO-2, potentially impacting its co-repressor functions.