PIK-75 free base is primarily used in biochemical and pharmacological research as a selective inhibitor of the PI3K (phosphoinositide 3-kinase) signaling pathway, particularly targeting the PI3Kα and DNA-PK (DNA-dependent protein kinase) isoforms. It is employed to study cellular processes such as proliferation, survival, and DNA repair, where PI3K and DNA-PK play critical roles. Due to its ability to cross the cell membrane and inhibit kinase activity at low concentrations, PIK-75 is valuable in experiments investigating cancer cell signaling and the effects of kinase suppression on tumor growth. It is also used in combination with other agents to assess synergistic effects in apoptosis induction and radiosensitization in cancer models. Its application remains limited to laboratory research and is not used in clinical or therapeutic settings.