Uncoupling Effect of F16 Is Responsible for Its Mitochondrial Toxicity and Anticancer Activity

Area of Science:

• Mitochondrial dysfunction
• Cancer cell biology
• Drug discovery

Background:

• F16 is a novel delocalized lipophilic cation that selectively accumulates in cancer cell mitochondria.
• F16 exhibits broad-spectrum antiproliferative activity against various cancer cell lines.
• Understanding the molecular mechanism of F16's cytotoxicity is crucial for developing new antitumor agents.

Purpose of the Study:

• To elucidate the mode of action and molecular mechanism underlying F16-induced cytotoxicity.
• To compare the effects of F16 with its precursor compound, (E)-3-(2-(pyridine-4yl)vinyl)-1 H-indole (PVI).
• To investigate the role of mitochondrial targeting and function in F16's anticancer activity.

Main Methods:

• Investigated the effects of F16 and PVI on cancer cells and isolated mitochondria.
• Assessed mitochondrial accumulation and cytotoxicity of both compounds.
• Evaluated mitochondrial structure and function following compound incubation.
• Conducted rescue experiments using adenosine 5 '-triphosphate (ATP).

Main Results:

• PVI did not accumulate in mitochondria and showed lower cytotoxicity than F16.
• Both F16 and PVI damaged mitochondrial structure and function, acting as mitochondrial uncouplers.
• Decreased intracellular ATP availability, induced by F16's uncoupling effect, was identified as a major factor in its cytotoxicity.
• The uncoupling effect was attributed to the shared chemical structure between F16 and PVI, independent of F16's positive charge.

Conclusions:

• F16-mediated cytotoxicity is primarily due to the uncoupling of mitochondria, leading to reduced intracellular ATP levels.
• The uncoupling mechanism is linked to the chemical structure common to F16 and PVI, not F16's cationic nature.
• These findings provide insights into F16's mechanism of action and guide the design of novel mitochondria-targeted anticancer drugs.