Mitochondrial damage prior to apoptosis in furanonaphthoquinone treated lung cancer cells
Eriko Simamura1, Kei-Ichi Hirai, Hiroki Shimada
1Department of Anatomy, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan. simamura@kanazawa-med.ac.jp
Abstract:
The mechanisms of the antitumor reactions of 2-methylnaphtho[2,3-b]furan-4,9-dione (FNQ3) to human lung adenocarcinoma A549 cells were investigated. A549 cells that received 1.25 microg/ml FNQ3 (IC(50) at 0.35 microg/ml) developed intensive mitochondrial H(2)O(2) production at 1 h. Selective structural mitochondrial swelling, alteration of mitochondrial membrane potential, and cytochrome c and caspase-9 release from the mitochondria occurred 18-24 h later. alpha-Tocopherol inhibited the alteration of both mitochondrial permeability and the leakage of procaspase-9. The caspase-9 was then activated in the cytosol. The expression of Bcl-2 oncoprotein was suppressed by FNQ3, and resulted in apoptosis. The higher dose of 5 microg/ml induced necrosis via severe mitochondrial breakage. These results showed that FNQ3 targets the mitochondria of A549 cells to produce a reactive oxygen species resulting in apoptosis and necrosis.
Insights
The compound 2-methylnaphtho[2,3-b]furan-4,9-dione (FNQ3) induces antitumor effects in lung cancer cells by targeting mitochondria. It triggers reactive oxygen species production, leading to apoptosis and necrosis.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Lung adenocarcinoma is a major cause of cancer mortality.
- Understanding the mechanisms of novel antitumor agents is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the antitumor mechanisms of 2-methylnaphtho[2,3-b]furan-4,9-dione (FNQ3) against human lung adenocarcinoma A549 cells.
- To elucidate the role of mitochondria and reactive oxygen species in FNQ3-induced cell death.
Main Methods:
- A549 cells were treated with varying concentrations of FNQ3.
- Mitochondrial hydrogen peroxide (H(2)O(2)) production was measured.
- Mitochondrial structure, membrane potential, and the release of cytochrome c and caspase-9 were assessed.
- The effect of alpha-tocopherol on FNQ3-induced changes was evaluated.
- Expression of Bcl-2 oncoprotein was analyzed.
Main Results:
- FNQ3 induced significant mitochondrial H(2)O(2) production in A549 cells.
- Mitochondrial structural changes, altered membrane potential, and release of cytochrome c and caspase-9 were observed.
- Alpha-tocopherol partially inhibited these mitochondrial alterations.
- FNQ3 suppressed Bcl-2 expression, promoting apoptosis.
- Higher FNQ3 doses led to necrosis through severe mitochondrial damage.
Conclusions:
- FNQ3 triggers apoptosis and necrosis in A549 lung adenocarcinoma cells.
- The primary mechanism involves targeting mitochondria to generate reactive oxygen species.
- FNQ3 demonstrates potential as an antitumor agent for lung adenocarcinoma.
