Mitochondria-Targeted Honokiol Confers a Striking Inhibitory Effect on Lung Cancer via Inhibiting Complex I Activity

Area of Science:

• Oncology
• Pharmacology
• Mitochondrial Biology

Background:

• Lung cancer, particularly metastatic forms, presents significant treatment challenges.
• Honokiol (HNK) exhibits anti-cancer properties but requires enhanced delivery for greater efficacy.
• Targeting mitochondria offers a promising strategy to increase anti-cancer drug potency.

Purpose of the Study:

• To synthesize and evaluate a mitochondria-targeted honokiol (Mito-HNK).
• To assess the in vitro and in vivo efficacy of Mito-HNK against lung cancer, including brain metastases.
• To investigate the mechanisms underlying Mito-HNK's anti-cancer effects and its impact on non-malignant cells.

Main Methods:

• Synthesis of mitochondria-targeted honokiol (Mito-HNK).
• In vitro assays measuring cell proliferation, mitochondrial function (complex I inhibition, ROS generation, Prx3 oxidation), and STAT3 phosphorylation.
• In vivo studies using orthotopic lung tumor xenografts and brain metastasis models in mice.

Main Results:

• Mito-HNK demonstrated over 100-fold greater potency than honokiol in inhibiting lung cancer cell proliferation.
• Mito-HNK effectively inhibited mitochondrial complex I, increased reactive oxygen species, oxidized peroxiredoxin-3, and suppressed mitoSTAT3 phosphorylation.
• In vivo, Mito-HNK induced cell death mediators and reduced invasion/proliferation pathways in brain metastases, while suppressing pro-metastatic pathways in the stroma without toxicity.

Conclusions:

• Mitochondria-targeted honokiol (Mito-HNK) is a highly potent and effective agent against primary and metastatic lung cancers.
• Mito-HNK exhibits significant anti-invasive and anti-metastatic effects, particularly in brain metastases, addressing a critical unmet need.
• Mito-HNK targets cancer cell metabolic vulnerabilities and shows potential as a standalone or combination therapy with reduced toxicity.