A PI polyamide-TPP conjugate targeting a mtDNA mutation induces cell death of cancer cells with the mutation

Area of Science:

• Mitochondrial genetics
• Cancer biology
• Drug discovery

Background:

• Mitochondrial DNA (mtDNA) mutations are common in cancer and can be homoplasmic.
• Targeting mtDNA mutations offers a potential strategy for selective cancer cell killing.
• Pyrrole-imidazole polyamides (PIPs) are DNA-binding molecules that can be modified for targeted delivery.

Purpose of the Study:

• To investigate the feasibility of using PIP conjugated with triphenylphosphonium (PIP-TPP) to target mtDNA mutations.
• To assess the efficacy of PIP-TPP in selectively killing cancer cells harboring specific mtDNA mutations.
• To evaluate the potential of PIP-TPP as a novel chemotherapeutic agent.

Main Methods:

• Synthesis of hairpin-type PIP-TPP targeting the A3243G mtDNA mutation.
• Surface plasmon resonance assay to determine DNA binding affinity.
• Cell viability assays using HeLa cybrid cells with and without the A3243G mutation.
• Mitochondrial localization and effects on reactive oxygen species (ROS), mitophagy, and apoptosis were assessed.

Main Results:

• PIP-TPP exhibited a 60-fold higher binding affinity for mutant G-containing DNA compared to wild-type A-containing DNA.
• PIP-TPP localized to mitochondria in cancer cells.
• Treatment induced significant mitochondrial ROS production, mitophagy, and apoptosis in cells with the mtDNA mutation.
• Minimal effects were observed in cells without the mutation.

Conclusions:

• PIP-TPP effectively targets specific mtDNA mutations with high selectivity.
• This targeted approach induces cancer cell death through mitochondrial pathways.
• PIP-TPPs represent a promising new class of chemotherapeutic drugs for cancer treatment with potentially reduced side effects.