Targeting BCL-xL in Myeloid Malignancies: From Inhibitors to PROTAC.

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Cancer cells evade apoptosis by overexpressing anti-apoptotic BCL-2 family proteins (BCL-2, BCL-xL, MCL1).
• These proteins are crucial for cancer cell survival and are attractive therapeutic targets.
• Inhibiting these proteins aims to restore apoptosis in malignant cells.

Purpose of the Study:

• To review the development of small-molecule inhibitors targeting BCL-2 family proteins.
• To discuss the challenges in designing effective inhibitors due to protein structural characteristics.
• To explore novel therapeutic strategies like PROTACs for cancer treatment.

Main Methods:

• Review of scientific literature on BCL-2 family inhibitors.
• Analysis of small-molecule inhibitor development, including ABT-263 and venetoclax.
• Discussion of structural challenges and emerging therapeutic modalities.

Main Results:

• Development of dual BCL-2/BCL-xL inhibitor ABT-263 and selective BCL-2 inhibitor venetoclax.
• Venetoclax demonstrated clinical efficacy in certain leukemia subtypes.
• Challenges persist in inhibitor design due to the shallow, hydrophobic BH3-binding groove.

Conclusions:

• Small-molecule inhibitors have advanced cancer therapy by targeting BCL-2 family proteins.
• Structural complexities of the BH3-binding groove limit inhibitor design.
• PROTACs targeting BCL-xL offer a potential future strategy to overcome current limitations.