Targeting the BCL2 Family: Advances and Challenges in BH3 Mimetic-Based Therapies

The BCL2 family of proteins plays a pivotal role in regulating apoptosis and cellular homeostasis, making them critical therapeutic targets in cancer and other diseases characterized by pathological cell survival. BH3 mimetics, small molecules that selectively inhibit anti-apoptotic BCL2 family members, have achieved significant clinical success, particularly in hematologic malignancies. However, several challenges remain, including resistance mechanisms, toxicity (such as MCL1 inhibitor-associated cardiotoxicity), and the intricate balance between apoptotic and non-apoptotic functions. This review provides a comprehensive overview of BCL2 family biology, the development and clinical application and outcomes of BH3 mimetics, and the emerging resistance mechanism known as double-bolt locking. We also examine strategies to overcome resistance, including combination therapies and immunomodulatory approaches. Beyond oncology, we highlight the expanding therapeutic potential of BH3 mimetics in autoimmune, fibrotic, and infectious diseases, as well as regenerative and anti-aging medicine. Finally, we discuss predictive biomarkers and tissue-specific responses that inform precision therapy. Together, these insights underscore the promise of BH3 mimetics and the need for continued multidisciplinary research to optimize their clinical impact.