Foxo3, also known as forkhead box O3, is a transcription factor belonging to the FOXO subfamily. It is widely expressed in various human organs and tissues, playing crucial roles in multiple biological processes. Its functions are mainly regulated by phosphorylation, which can influence its subcellular localization and transcriptional activity. It is involved in pathways such as inflammation, autophagy, apoptosis, oxidative stress response, and cell cycle regulation, and is of great biological importance in maintaining cellular homeostasis and organismal health [4].

In hepatocellular carcinoma, inhibition of CDK9 promotes dephosphorylation of SIRT1, leading to FOXO3 protein degradation, transcriptional repression of FOXO3-driven BNIP3, and ultimately blocking PINK1-PRKN-mediated mitophagy initiation. This finding reveals the potential of targeting mitophagy through the SIRT1-FOXO3-BNIP3 axis for HCC treatment [1].

In osteosarcoma, COPS3 upregulates the nuclear abundance of FOXO3, promoting autophagosome formation and maturation, and in turn, FOXO3 maintains a high level of COPS3. Targeting COPS3-mediated autophagy via FOXO3 may be a promising strategy to overcome cisplatin resistance [3].

In the context of blood-brain barrier damage during ischemia/reperfusion, circ-FoxO3 promotes autophagy via mTORC1 inhibition to attenuate BBB collapse, suggesting it could be a therapeutic target for related neurological disorders [2].

In summary, Foxo3 is essential in regulating various biological processes. Through model-based research, especially in disease-related contexts like cancer and ischemia/reperfusion injury, it has been shown to play key roles in processes such as autophagy and mitophagy, which are potential therapeutic targets. Understanding Foxo3's functions helps in developing strategies for treating diseases like hepatocellular carcinoma, osteosarcoma, and neurological disorders associated with blood-brain barrier damage.