Potential-dependent membrane permeabilization and mitochondrial aggregation caused by anticancer polyarginine-KLA...

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Anticancer peptides like KLA show potential but require enhanced delivery.
• Hepta-arginine (r7 and R7) sequences are known cell-penetrating peptides.
• Fusion of KLA with r7/R7 aims to improve its anticancer efficacy.

Purpose of the Study:

• To investigate the enhanced anticancer activity of KLA fused with r7/R7.
• To elucidate the mechanism of action of these fusion peptides on mitochondria.
• To determine if these peptides can permeabilize biological membranes.

Main Methods:

• Preparation and testing of r7-kla and R7-KLA fusion peptides.
• Mitochondrial membrane permeabilization assays using energized rat liver mitochondria.
• Assessment of mitochondrial aggregation and metabolic activity inhibition.
• Red blood cell plasma membrane permeabilization studies.

Main Results:

• r7-kla and R7-KLA (3.6μM) significantly permeabilized both inner and outer mitochondrial membranes.
• Unfused KLA did not cause significant permeabilization.
• Fusion peptides induced mitochondrial aggregation, leading to metabolic activity inhibition.
• Potential-dependent membrane permeabilization was observed for both mitochondrial and red blood cell membranes.

Conclusions:

• Polyarginine vectors enhance the direct membrane-permeabilizing ability of anticancer peptides.
• Fusion peptides introduce a novel cytotoxic mechanism involving mitochondrial aggregation.
• These findings suggest a new strategy for developing potent anticancer peptide therapeutics.