Arenobufagin suppresses lung cancer cell growth by disrupting mitochondrial function and inducing relocalization of ATP synthase.

Lung cancer has the highest incidence and mortality rates among all cancers worldwide. Arenobufagin, a steroidal lactone of the bufadienolide class, has been reported to possess anti-tumor activity and to inhibit Na/K-ATPase. In this study, we investigated the effects of arenobufagin on lung cancer cell growth and its underlying mechanisms. We found that arenobufagin inhibits lung cancer cell proliferation and colony formation, and induces apoptosis at nanomolar concentrations. Mechanistically, arenobufagin disrupts mitochondrial membrane potential and function, thereby triggering apoptosis. Mass spectrometry analysis further identified ATP synthase as a cellular target of arenobufagin. Notably, arenobufagin treatment promotes the translocation of ATP synthase from mitochondria to the plasma membrane, a process associated with reduced intracellular ATP production and increased extracellular ATP release. Collectively, our findings establish arenobufagin as a regulator of cancer cell energy metabolism by modulating ATP synthase localization and mitochondrial function.