Kidney-Type Glutaminase Inhibitor Hexylselen Selectively Kills Cancer Cells via a Three-Pronged Mechanism

Area of Science:

• Biochemistry
• Oncology
• Pharmacology

Background:

• Tumor metabolism is a key target for cancer therapeutics.
• Glutamine deficiency alone is insufficient for complete cancer cell growth inhibition.
• Existing kidney-type glutaminase (KGA) inhibitors often lack satisfactory in vivo efficacy.

Purpose of the Study:

• To evaluate the efficacy of a novel KGA/glutamate dehydrogenase (GDH) inhibitor, Hexylselen (CPD-3B).
• To investigate the molecular targets and signaling pathways affected by CPD-3B.
• To assess the in vivo therapeutic potential of CPD-3B in aggressive cancer models.

Main Methods:

• In vitro cell growth inhibition assays.
• Enzyme inhibition assays for KGA, GDH, thioredoxin reductase (TrxR), and amidotransferase (GatCAB).
• Western blot analysis of Akt/Erk/caspase-9 signaling pathways.
• In vivo liver cancer xenograft model studies.

Main Results:

• CPD-3B completely inhibited the growth of aggressive cancer cell lines with no toxicity to normal cells at tested concentrations.
• CPD-3B targets KGA, GDH, TrxR, and GatCAB, modulating Akt/Erk/caspase-9 signaling.
• CPD-3B significantly reduced tumor size, induced tissue damage, and improved survival in a liver cancer xenograft model.

Conclusions:

• CPD-3B demonstrates superior efficacy compared to other KGA inhibitors, including CB-839.
• CPD-3B's multi-target inhibition provides a promising therapeutic strategy for aggressive cancers.
• These findings offer valuable insights for designing novel anticancer KGA allosteric inhibitors.